CA2242797A1 - Composition of cyclic amine-initiated elastomers and silica and process for the production thereof - Google Patents
Composition of cyclic amine-initiated elastomers and silica and process for the production thereof Download PDFInfo
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- CA2242797A1 CA2242797A1 CA002242797A CA2242797A CA2242797A1 CA 2242797 A1 CA2242797 A1 CA 2242797A1 CA 002242797 A CA002242797 A CA 002242797A CA 2242797 A CA2242797 A CA 2242797A CA 2242797 A1 CA2242797 A1 CA 2242797A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F36/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
- C08F36/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
- C08F36/04—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08C19/00—Chemical modification of rubber
- C08C19/30—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule
- C08C19/42—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups
- C08C19/44—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with metals or metal-containing groups of polymers containing metal atoms exclusively at one or both ends of the skeleton
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/34—Silicon-containing compounds
- C08K3/36—Silica
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S152/00—Resilient tires and wheels
- Y10S152/905—Tread composition
Abstract
The reduction of hysteresis in a silica-filled, vulcanized elastomeric compound is produced by mixing diene monomer and optionally monovinyl aromatic monomer with a lithium amine initiator and, optionally, a modifier; effecting polymerization conditions;
terminating polymerization with an amino group producing terminator to form an amine functionalized diene elastomer; compounding the amine functionalized diene elastomer will an amorphous silica filler and a vulcanization agent; and, effecting vulcanization. A
pneumatic tire tread stock incorporating the vulcanized elastomer compound exhibits improved reduced hysteresis, or highly balanced wet traction, rolling resistance, snow/ice traction, and mechanical strength when compounded with silica filler and vulcanized, in the tire.
terminating polymerization with an amino group producing terminator to form an amine functionalized diene elastomer; compounding the amine functionalized diene elastomer will an amorphous silica filler and a vulcanization agent; and, effecting vulcanization. A
pneumatic tire tread stock incorporating the vulcanized elastomer compound exhibits improved reduced hysteresis, or highly balanced wet traction, rolling resistance, snow/ice traction, and mechanical strength when compounded with silica filler and vulcanized, in the tire.
Description
Composi~ion of Cyclic Amille-IIliti~te(l l~lastomers and Silica and Process for the Production T~lereof TECIINIC~L FIEI,D
The subject invention relates to the composilioll of silica and aniollically polymerized diene polymer and copolymer elastomers. More specifically, tlle p resent invention relates to anionic polymerizalion employing lilhium amille inilia~ors an(l various terminator compounds providing improved dispersion of silica in elastomeric compounds.
Silica filled compounds which include these functional diene polymers and copolymers prepared according to tl1e present invention, llave reduced llysleresis characteristics and improved balance of hysteresis properties with wet traction or snow and ice traction. Articles such as tires, power belts and the like, are typical applications with tires being particularly preferred.
I~ACKGROUND OF T~IE INVI~NTION
In the art it is desirable to produce elastomeric compounds exhibiting reduced hysteresis when properly compounded with other ingredients such as reinforcil1g agcnts, followed by vulcanization. SUCII elaslomers, w!len compounded, fabricalcd and vulcanized into components for constructing articles such as tires, power belts, and the like, will manifest properties of increased rebound, decreased rolling resistance and less hcat-build up when subjected to mechanical stress during normal use.
The llystcresis of an elaslomeric compound rerers to the differel1ce bctwccll the energy applied to deform an article made from the elastomeric compound and the energy released as the elastomeric compound returns to its initial, ullderormc(l sla~e.
In pneumatic tires, lowered hysteresis properties are associated with rcdllced rolling resistance and heat build-up during operation of the tire. These properties, in tum, result in such desirable characteristics as lowered fuel consumption of vehicles using sucll tires.
In such contexts, the property of lowered hysteresis of compoul1ded, vulcanizable elastomer coml~ositions is particularly signirlcant. Examplcs of sllcll compounded elastomer systems are kno~vn to the art and are comprised of at least one elastomer (that is, a natural or syntlletic polymer exhibiting elastomeric properties, such 9702011 1s5 - 2 -as a rubber), a reinforcing filler agent (such as finely divided carbon black, lherl1lal black, or mineral fillers such as clay and the like) an~ a vulcanizing sys~eltl ~uch as sulfur-containing vulcanizing (that is, curing) system.
Previous atteml~ts at l-rel-aring reduced hysteresis r~roducls have foc1lsc(1 ul~oll increased interaction between tlle elastomer and tlle COlllpOU11(3illg materials SUCIl as carbon black, including high temperature mixing of the filler-rubber mixtures in the -resence of selectively-reactive l-romoters to promote coml~ounding material rcinforcement, surface oxidatioll of the coint~oundillg materials, chemical mo(lirlcatiolls to tlle terminal end of l~olymers USillg 4,4'-bis(dimetllylamino)benzopllellolle (Miclller's ketone), tin coupling agents and tllc like and, surface graf~ g.
Various organolithium polymerization ini~iators are also known in tlle art.
U.S. Pat. No. 3,439,049, owned by tlle Assignee of record, discloses an organolithiu initiator prepared from a halophenol in a llydrocarbon mediuln.
U.S. Pat. No. 4,015,061 is directed toward amino-functional initiators wllich polymerize diene monomers to fontl mono- or di-l~rimary aryl amille-lerlllillatcd dielle polymers ur~on acid hydrolysis. U.S. Pat. No. 4,914,147 discloses terminal modifyillg agents including dialkylamino-substituted aromatic vinyl com~ounds such as N,N'-dimethylamino benzo~henone and p-dimetllylamino styrene, in rubber coml~ositionshaving reduced hysteresis characteristics. In U.S. ~'at. No. 4,894,409, an amino groull-containing monomer, such as 2-N,N-dimethylaminostyrene is ~olymerized to form anamino group-containing diene based l-olymer.
Other r~atents owned by the assignee of record, directed to aminc-contaillillg r)olymerization initiators and terminators include U. S. Patellt Nos. S,238,893;5,274,106; 5,329,005; 5,332,810; 5,393,721; 5,496,940; 5,508,333; 5,519,086;
5,521,309; 5,523,371; and 5,552,473. Lawson, et al., in A~1ioniC Pol~mer-iz-7~iort ~f Dienes Usirlg l~orrloger1eol~s lit~ rrl Arrli~e (N-Li) Ini~ )r.s ACS l'rc~-rillt, I'olynlcr Division, 37 (2) 1996, at l-age 728, disclosed that, for call~ lack-fillcd COltll~OInl(lS, cyclic amino lithium initiators of a certain size l-rovided elastomeric comlnolmds exhibiting reduced hysteresis.
Precipitatcd silica has been increasillgly use(l as a reinforcing l-articula~c filler in rubber comllonents of tires and mechanical goods. The reason silica is used in tires is that silica allows one to iml~rove tlle l-erformance halance between wet tractio n and rolling resistance, snow/ice traction and, mechanical properties such as wear 9702011 155 _ 3 - performance. Silica-loaded rubber stocks, however, have heretofore exhibited relatively poor resilience and high compound viscosity when used witllout any silane-coupling agent wllicll is somewllat expensive to be widely used in the industry. Even witll a certain amount of silane-coupling agent, total balance of the foregoing performances was 5 often not sufficient.
The present invention provides initiators for anionic polymerization whicll become incorporated into t}le elastomer chain, as well as various tenninators for the polymerization, and produce functional groups wllicll greatly improve the dispersability Or silica filler lhrougllout the elaslomeric composilion during compoullding. As will l)c 10 described hereinbelow, these initiators contain amine groups.
This invention utilizes a combination of silica and polymer with amille prodllcing initiators to increase dispersion of silica rlller in diene polymer and copolymer elastomeric compounds, and to thereby reduce tlle hysteresis of the cured compounds or improve mechanical properties through the interaction (reinforcement) between silica 15 and amine functionalities of the polymer. By this one could even reduce the amount of expensive silane-coupling agent.
SUMMARY OFINVENTION
It is therefore an object of the present invention to provi(le anionic 20 polymerization initiators and terminators WlliCIl improve the dispersion or reinforcement of silica filler in diene polymer elastomers.
It is another object of the present invention to provide a method for reducing thc hysleresis of siliGa-fillc(l elastonleric vulcanizal-le coml-ollnds.
It is anotiler objecl of the presellt invention to provide vulcanizable silica-25 filled elastomeric compounds, which upon vulcanization, exllibit reduced hysteresis.
It is still another object of the present invention to provide an imllrovedpneumatic tire having decreased rolling resistance.
- It is yet another object of the present invention to provide an improved pneumatic tire having improved balance of wet traction, snow and ice traction, 30 hysteresis properties and mechanical strength.
At least one or more of the foregoing objects, together with the advantages thereof over the existing art, whicll shall become apparent from the specirlcation whicl follows, are accomplished by the invention as hereinafter described and claimed.
- ~702011 155 , _ 4 The present invention provides a process for ~he production of diene-based elastomeric compositions having improved reduced llysteresis, or lligllly balanced wet traction, rolling resistance, snow/ice traction, and mechanical strengtll wllen compounded with silica fller and vulcanized, tlle process coml-rising mixing a diene S monomer and optionally a monovinyl aromatic monomer or a triene with a litllhllll amine initiator compound optionally in the presence of a modirler, wherein tlle li~llium amine initiator compound is selected from the group consisting of compounds of the formulas R'-N-Li and R'-N-R"-Li wherein R' is a cyclic anlille group havillg 3 to 18 ring carbon atoms and, togetller wilh the nitrogen, a ring or 4 to 19 atollls, and whereill 10 R" is a divalent llydrocarbyl group of 2 to 20 carbons, wherein tlle litllium a~om is not bonded to a carbon whicll is directly bomled to tl~e anlille nitrogell; crrectil~g polymerization conditions; terlllinatillg polymerization wi~ll a ter~ la~ing agellt to ron a functionalized diene elastomer; compounding the functionalized diene elastomer witll an amorphous silica filler, and a vulcanization agent; and, efrec~ing vulcaniza~ion or tlle 15 silica filled, functionalized diene filled elastomeric compound.
l lle present invention further provides a vulcanizable silica-filled COml~OUIl(l comprising a diene elastomer containillg a lithiulll amille ini~iator-(lerived func~iol1ali~y and a functionality derived from a terminator, a silica filler, and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of a litllium amine 20 initiator derived from a reaction of a secondary amine with a hydrocarbyl li~hium and of the formula R'N-Li, wherein R' is a cyclic anline group having 3 to l8 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 alollls.
The present invention still fur~her llrovides a vulcanizable silica-filled coml~ound comprisillg a diene elastomer contaillillg a lithiulll amille ini~ia~or-(lerive(l 25 functionality and a functionality derived from a terminator, a silica filler, and a vulcanization agent, whereill tlle lithium amine initiator-derived fullc~ionali~y is a residue of a lithium-hydrocarbon substituted tertiary amine of the formula initiator derived from a reaction of a secondary amille wi~h a hydrocarbyl lithiulll an~l of ~he rolmula R'N-R"-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, tnge~her 30 wi~ll the nitrogen, a ring of 4 to 19 atoms, and whereill R" is a divalen~ hy(lrocarhyl group of 2 to 20 carbons and the lithium atom is not bonded to a carbon wllicll is directly bonded to the amine nitrogen.
97n2011155 - 5 -The present invention fur~her provides a vulcanizable silica-filled compound comprising a diene elastomer containing a li(hium amine ini~ia~or-derived functionali~y and a functionality derived rrom a terminator, the termillator heing devoid or an alkoxysilane group; a silica filler; and a vulcanizatioll agent, whereill ~he lithilllll anlillc 5 initiator-derived functionality is a residue of an initiator derived or the rnrmula R'-N-R"-r-Lit wllerein R' is a cyclic amille group having 3 to 18 ring carbon atnms an(l, logcthcr with the ni~rogen, a ring of 4 to 19 a(oms, wherein R" is a divalent llydrocarbyl groul-of 2 to about 20 carbons and whereill 1~ is a diene-type oligomer having from I to abou~
100 diene monomer units; wherein tlle dicne monc)mer is isoprelle or 1,3-bula(3iclle.
DETAILED DESCRIrTION OF TIIE rREFERREI) ~ OI)I~ENTS
In general, the present invention provides the obtainment Or cllllallcccl polymer filler interactions Witll silica, thereby providillg vulcanizable elastomers ror tlle manufacture of articles SUCll a pneumatic tires having iml-roved reduced hysteresis, or 15 highly balanced wet trac~ion, rolling resistance, snow/ice traction, and mecllallical strength. This is accomplished by the use of cyclic amillo con~aining ini~iators (i.e., li~hium amine ini~iators) and, prererably, amino group producitlg terminators. 13y "amino group producing terminator" is meant a nitrogen containing precursor compound which acts as a terminator for a "living" diene polymer, and wllicll arter terll-illation, 20 contains or provides an amino group to form an amine runctionalized diene elastomer.
Such a combination of both cyclic amino contailling initiators and amillo groul-producing termina~ors has the advanlage lhal tllc iniliatioll will put a reactive gro~ On almost all of ~he polymer chains and ~hen any addi~ional end capring during tenllinalion will give polymers having an increased level of reactivity towards silica rlller when 25 compared to conventionally inilialed polymers modiried only by termination.
The li~hium amine initia~ors used in ~he presell~ inven~ion include li~hiuln imides wherein a lithiulll atom is direclly bonded to the nitrogell Or a sccondary amille or (lithium-llydrocarbyl) substitu~ed amine wherein the lithiullt alom is directly bollded to a carbon wllicll is part of a hydrocarbyl group wllicll, in turn, is bonded to a nitrogell.
30 Representative of the rormer (i.e., li~hium bondcd ~o ni~rogen) are coml-ollllds Or ~lle structural rormula R'N-Li, and or the la~ter (i.e., lilhi~ bollde(l to a carlon~, compounds of the structural formula R'N-R"-Li, whereill each R' in ei~her forlllula is a part oF a cyclic amine group, bonded toge~her witll the nilrogen and the olher R', and 97~2011155 - 6 -R" is a divalent hydrocarbyl group, preferably havillg 2 to 20 carbons. More particularly, the two R' groups may be bonded together to rorm, with the nitrogen, a cyclic amine group preferably having 3 to 18 ring carbon atoms and, together with tlle nitrogen, prererably a ring of 4 to 19 atoms. An example of this cyclic amine group is a cyclic methylene ring of 4 to 18 methylene groups. It will be appreciated the R" may furtl1er include additional non-hydrocarbyl components within the structural rormula.
~or example, R" may include morpholine or alkyl piperazine. In the la~ter romlula, it will be appreciated that the lithium atom is preferably not honded to a carbon whicll is directly bonded to the amine nitrogen, but ratller, is separated by at Ieast one, and more 10 preferably, at least 3 carbon atoms.
The lithiuln anline initiators according lo lhe presellt invell~ion, are enlploye(l to prepare any anionically-polymerized elastomer, e.g., polyhutadiene, polyisoprelle an~
the like, and copolymers thereof with monovinyl aromatics sucll as styrene, alplla metllyl styrene and the like, or trienes such as myrcene. Thus, tlle elastomers include diene 15 homopolymers, A, and copolymers thereof with monovil1yl aromatic p01ylllers, B.
Exemplary diene homopolymers are those prepared from diolerln monomers havillg fronl 4 to about 12 carbon atoms. Exemplary vinyl aromatic polyl1lers are lhosc prel-ared from monomers having from 8 to about 20 carbon atorns. Examples of conjugated diene monomers and the like userul in tlle present invention include 1,3-butadiene, isoprelle, 20 1,3-pentadiene, 2,3-dimetllyl-1,3-butadiene and 1,3-hexadiene, and aromatic vinyl monomers include styrene, ~x-metllylstyrene, p-llletllylstyrene, vinyltoluelles all(l vinylnaphtalenes. The conjugated diene monomer and aromatic vinyl monomer are normally used at tlle weigllt ratios of ahout 90/10 lo about 55/45, prererahly abollt 80/20 to about 65/35.
rreferred elastomers include diene homopolymers such as polybutadiene and polyisoprene and copolymers such as styrene butadiene rubber (SBR). Copolymers can comprise from about 99 to 55 percent by weight of diene ullits and from al-out I to about 45 percent by weight of monovinyl aromatic or triene units, totaling tO0 percent.
The polyl1lers and copolymers Of the presellt inventioll may have the (liene pO~ ll witll 30 a 1,2-microstructure contents ranging from about 10 to about 80 percent, with the preferred polymers or copolymers having 1,2-microstructure contents of frolll al~out 12 to about 65 percent. The molecular weight of the polymer lhat is produced according to the present invention, is preferably such that a proton-quenched sample will exhibit - 970201 1 ~55 _ 7 a gum Mooney viseosity (ML4/212~F) of from about 10 to about 150. The copolymersare preferably random eopolymers whieh result from simullaneous copolymerizalion Or lle monomers, as is known in the art.
The initiators eontaining eyelie amines, aeeording to the present inventioll, 5 preferably include N-lithiollexamethyleneimide, hexametllyletleiminoprol~yllillliurn, and lithiated adduets of eyelie amines, such as adducts of hexamelllyleneill1ine wi~h 1,3-butadiene, isoprene, 1-3-diisopropenylbenzene and ortho-xylene.
Still other lithium amine initiators include those compounds of the structural formula R'N-R"-P-Li, wherein R' is again a cyclic amine group having 3 to 18 ring 10 earbon atoms and, ~oge~her wi~h tllC nilrogen, a ring Or 4 ~o 19 alom.s, 1~" is agaill a divalent hydrocarbyl group of 2 to 20 earbons, and P is a diene - type oligomer having I to 100 diene monomer units. Preferably, the diene mollomer is selec~ed from ~lle group eonsisting of isoprene or 1,3-butadiene. It will be ar~preciated llla~, wllile oligomers typieally do not include more than about 50 monomer units, ~he word 15 "oligomer" has been used in tllis instance to denoted the p otential strueture as having up to about 100 monomer units.
Polymerization is usually conducted in a convenlional solvent for anionic polymerizations such as tlle various eyelie and acyclic hexanes, llelltalles, octalles, pentanes, their allcylated derivatives, and mixtures thereoF, as well as aromalic solvellls 20 such as benzene, t-butylbenzene, toluene, and the like. O~her lechlliques forpolymerization, such as semi-batch and continuous polymerization may be employed.
In order to promote ran(lomization in copolymerization an(l to increase vinyl content, a modifer may optiollally be added to tlle polymerization ingredients. I~mollllts range between 0 to 90 or more equivalent.s per equivalellt of litlliuln. l'he anl(Illllt depell(l~s 25 upon the amount of vinyl desired, the level of styrene employed and the temperature of the polymerizations, as well as the nature of the specific polar coordinator (modifier) employed.
- Compounds useful as modifiers are organic an(l include those havillg all oxygen or ni~rogen he~ero-a~om and a non-bonded pair of electrons. Examples include 30 dialkyl e~hers of mono and oligo alkylene glyeoLs; "crown" e~hers; tertiary amille~s SllCh as tetramethylethylene diamine (TMED~); TIJ~; Tll~ oligomers; linear and eyelic oligomeric oxolanyl alkanes, such as 2-2'-di(tetrahydrofuryl) propane, di-piperidyl ethane,hexamethylphosphoramide, N-N'-dimethylpiperazine,diazabicyclooctalle,dietllyl etller, tributylamine and the like. Details of linear and cyclic oligomeric oxolanyl modirlers can be found in U.S. rat. No. 4,429,091, owne~ by tlle ~ssignee of record, the subject matter of whicll is incorporated herein by reference.
Polymerization is usually begun by cllarging a blend of the mollolller(s) and S solvent to a suitable reaction vessel, followed by the addition of the modifier an(l the initiator. ~Iternatively, the monomer and modifier can be added to the initiator. The procedure is carried out under anllydrous, anaerobic conditiolls. The teaclall~s are lleated to a temperature of from about 10~ to about 150~C all(l are agilated ror al-ollt 0.1 to 24 hours. After polymerizatioll is complete, the product is removed from the heat 10 and terminated in one or more ways.
To terminate the polymerization, a terminating agent, couplillg agent or linking agent may be employed, all of these agents being collectively referred to herein as "terminating agents". Certain of these agents may provi(le the resulting polylller wi~h a multifunctionality. That is, the polymers initiated accordillg to the present invelltioll, 15 carry at least one amine functional group as discussed hereillabove, and may also carry a second functional group selected and derived from the groul7 consisting of terminating agents, coupling agents and linking agents.
According to the present invention, useful terminating, coupling or linking agents include an amino producing group, exemplirled by but not limiled to llle 20 following: 4,4'-bis(dialkylamino)benzopllenolle (such as 4,4'(dimetllylalllinn)-benzophenone or the like); N,N-dialkylamino-benzaldehyde (such as dime~hylalllillo-benzaldellyde or tlle like); 1,3-dialkyl-2-imidazolidillolles (sucll as 1,3-(linlelllyl-2-imidazolidinone or the like); I-alkyl subsliluled pyrrolidinones; I-aryl suhslilu~e(l pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about S to about 20 25 carbon atoms;
R2--N~N - R2 9702011155 _9 _ N~CH=O
~\N--R2 / N~\O~N=CH--R3 ~5 and, / N~ CH=N--~5 ;
wherein each R2 is the same or different and is an alkyl, cycloalkyl or aryl, having from I to abou( 12 carbon atoms. ~or examl-le, R2 tnay include mc~hyl, clh nonyl, t-butyl, phenyl or the like.
R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophellyl, having frolll I
to about 20 carbon atoms. ~or example, R3 may include ~-b-l~yl, 2-mctllyl-4-1-ell~ene-2-yl, phenyl, p-tolyl, p-butylphenyl, p-dodecylphenyl, p-dietllyl-alllino~llenyl, p-(pyrrolidino)phenyl, and the like.
Each R4 is tlle same or differen~, and is an alkyl or cycloalkyl havill~ fr 1 lo about 12 carbon aloms. Two of ~hc R4 groups may ~ogetller ~orm a cyclic ~ro~
For example, R4 may include methyl, ethyl, octyl, tetramethylene, pentametllylene, cyclohexyl or the like.
9702011 155 _ 1O _ - Rs may include alkyl, phenyl, alkylphenyl or dialkylaminop11enyl, llaving from I to about 20 carbon atoms. ~:or example, Rs may include me~hyl, butyl, phenyl, p- butylphenyl, p-nonylphenyl, p-dimethylaminol~hellyl, p-diethylaminol~lleIlyl, p-(piperidino)phellyl, or the like.
Olller useful terminating agents may include lhose of the slructural fonllula (Rl)a ZXb, wherein Z is tin or silicon. It is preferred that Z is tin, and when it is, Rl is an alkyl having from I to about 20 carhon atoms; a cycloalkyl havillg frolll al-out 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20 carbon aloms. ~or example, Rl may include me~hyl, e~hyl, n-butyl, neophyl, pllenyl, cyclollexyl or the like. When Z is tin, X is a halogen such as chlorille or hrnmille, or an alkoxy, "a" is froln 0 lo 3, an(l "b"
is from about I to 4; where a + b = 4. Examples of such terminatillg a~en~s inclll(le tin tetracllloride, (Rl)3SnCI, (Rl)2SnC12, RISnCl3, RISn(ORl)3 and (Rl)2Sn(OR)2.When Z is silicoll, tllen Rl is again an alkyl having from I to 20 carbo a~oms, a cycloalkyl having from abou~ 3 to about 20 carbon atoms; an aryl havillg fronl about 6 to about 20 carbon atoms; or, an aralkyl havillg from about 7 to about 20 carbon a~oms. Tha~ is, Rl, may again be methyl, ethyl, n-bu~yl, nenl hyl, r~hellyl, cyclohexyl or tlle like. X in tlle formula provided hereinabove is only a halogen, SIICIl as chlorine or bromine when Z is silicon. Tha~ is, alkoxysilanes, Si(OR)x wllerein R
is an alkyl, cycloalkyl, aryl, or aralkyl, are particularly exclude(l. In fact, it is preferre(l tha~ the terminating agent be devoid of any alkoxysilane groups. Examples of desirahle terminating agents include RISiC13, (Rl)2SiC12, (Rl)3SiCI and silicon tetrachlori(le.
Examples of additional terlnilla~ing agellts include water, s~ealll, an alcohol such as isopropanol, carbodiimides, N-methylpyrrolidine, cyclic amides, cyclic ureas, isocyanates, Schiff bases, 4,4'-bis(diethylalllino) benzol-llenone, and the like.
The tenllinating agent is added to the reac~ion vessel, an(l ~he vessel is agitated for about I to about 1000 minutes. /'~s a reslllt, an elastomer is pro(lllced llaving an even greater affinity for silica compounding materials, and hellce, even further reduced hystercsis. ~dditional examllles of temlinalillg agellts inclllde ~llose found in U.S. ~atent No. 4,616,069 whicll is hereill incorl-orate(l hy rercrence. 1~ is lo be understood tllat practice of tlle l~resent inventioll is not limited solely to tllese terminators inasmucll as other compounds that are reac~ive witll the r~olymer holllld litllium moiety can be selected to provide a desired functional group.
970~ 55 ~ Quenchillg is usually conducted by stirring the polymer and quenching agent for about 0.05 to about 2 llours at temperatures of from about 30~ to 120~ C to ensure complete reaction. Polymers terminated with a fimctional group as discIlssed hereinabove, are subsequently quenched with alcohol or other quenclling agent as5 described hereillabove.
Lastly, the solvent is removed rrom the polylller b y conventiollal techlliques such as drum drying, extruder drying, vacuum drying or the like, whicll may be combined wi~h coagulation with water, alcohol or steam, thermal desolventization, or any other suitable melhod. If coagulation with water or steam is used, oven drying may I0 be desirable.
The functional group or groups contained in the elastomer of this inveIltioll have an affinity for silica. Such compounding results in products exhibitirlg reduced hysteresis, which means a product having increased rebound, decreased rolling resistance and having lessened heat build-up when subjected to mechanical stress or I5 higllly balanced wet traction, rolling resistance, snow/ice traction and mecllaIlical strength. Products including tires, power belts and the like are envisioned. Decreased rolling resistance is, of course, a useful property for pneumatic tires, both radial as well as bias ply types and thus, the vulcanizable elastomeric compositions of the l7resent invention can be utilized to form treadstocks for such tires.
The polymers of the present invention can be utilized as 100 parts or the rubber in the treadstock compoIlnd or, tlley can l e blellded with any cnnvelltiollally employed treadstock rubber whicll inclu(les natural rubber, sylltlletic mhber and l-lellds tl1CreOf. SUCII rubbers are well known to tllose skilled in the art and include syntlletic polyisor~rene rubber, styrene/butadielle nlbber (S13R), I-olyblltadielle, hlltyl tul-l-cr, neoprene, ethylene/propylene rubber, ethylene/propylelle/dieIle rubber (ErDM), acrylonitrile/butadiene rubber (NBR), silicone rubber, the fluoroelastomers, ethylelle acrylic rubber, ethylene vinyl acetate copolymer (EVA), epichlorollydrin rubbers, chlorinated polyethyleIle rubbers, chlorosulrollated l~olyelhylene rubhers, hs~drogen~ed nitrile rubber, tetratluoroethylene/propyleIle rubber and the like. Whell the polylllers or the present invention are blended with convelltional nlhbers, the al~ s Call vary widely in a range comprising about 10 to about 99 percent hy weight Or the ~o~al rubber.
It is to be appreciated that the minimum amount will depend primarily ul-on the degree of reduced hysteresis or performance balance that is desired.
97mO11 155 - 12 -- Aecording to the present invention, amorphous siliea (silicon dioxide) is utilized as a rlller for tlle elastomer. Silicas are generally classed as wet-l~rocess, hydrated silicas because they are l~roduee(l by a ehemieal reaetinn in water, frotll wllicll tlley are preeipitated as ultrafine, spherical partieles. Silica filler llas foulld limited use 5 in the past, however, because it is acidic in nature and interferes witll the cure process.
Compensation for this phenomenon has been required.
These ~rimary l~articles strongly associate into aggregates, whicll in turn combine less strongly into agglomerates. The surface area, as measured by the BEI
mclllo(l giVCS lhe besl measure of llle reinrorcillg characler Or ~lirrerellt silic.ls. I or 10 silicas of interest for tlle present invention, tlle surface area ~lloul(l be about 32 to about 400 m2/g, with tlle range of ahoul lO0 lo about 250 nl2/g heing ~referre(l, an(l lhe range of about 150 to about 220 m2/g being most pre~erre(l. The ~ of tlle silica filler is generally about 5.5 to about 7 or slightly over, prererably ahout 5.5 to ahollt 6.8.
Silica can be employed in the amount of aboul I part to about lO0 par~s per 100 parts of polymer (pllr), preferably in an amoullt rrom ahout 5 to ahove 80 r~llr. Tlle userul upper range is limited by the high viscosity imr~arted by rlllers of this type. Some of the eommercially available silieas WhiCIl may he used inelude~ Sil~ 190, lli-Sil~
215, and l~i-Sil~ 233, produeed by P~'G Industries. Also, a number of useful eommereial grades of different silieas are available from De Gussa CorporatioIl, Rllolle 20 Poulene, an(l J.M. Iiuber Corpora~ion.
The polymers may also be eompounded witll all forms of carbon black in amounts ranging fron1 about 0 to about 50 parts by weight, per 100 parts of rubber (pllr), witll ICSS tllan aboul S pllr being prererred. l he carhon blacks may inclll(le any of lhe eommollly available, comlllereially-prodllee(l carh(lll blacks bu~ ~hose llaving a surfaee area (EMSA) of at least 20 m2/gram ancl more preferably at least 35 m2/gram up to 200 m2/gram or higller are preferre(J. Surfaee area values use(l in ~llis ar~l-licalinn are lhose (letermine~l by ASTM test D-1765 using llle celyltrime~llyl-amlllonilllll hromi(le (CTAB) technique. Among the useful carbon blacks are furnace black, cllannel blacks and lamp blacks. More specifically, examples of the carbon blacks include super abrasion furllace (SAF) blacks, higll al-rasion furllace (llAI~) blacks, fast e~msioll furnace (~EF) blacks, rlne furnace (FF) blacks, intermediate super abrasion filrnace (ISAI;) blacks, semi-reinrorcillg furllace (SRl~) hlacks, IllC(Iilllll l~rOCCSSillg ChallnCI
blacks, hard processing channel blacks and conducting cllannel blacks. Other carbon blacks which may be utilized include acetylene blacks. Mix~ures of two or more of tlle above blacks can be used in preparing the carbon black products of the invention.
Typical values for surface areas of usable carbon blacks are summarized in the TABLE
I hereinbelow.
- TA~LE I
Carbon Blacks ~STM DesignationSurface Area (m2/g~
(D-1765-82a) (D-37G5) N-l 10 126 N-339 . 9S
: N-550 42 The carbon blacks utilized in the preparation of the rubber compounds of the 15 inven~ion may be in pelletized form or an unpelletized tlocculent mass.
The reinforced rubber compounds can be cured in a convenlional manller with known vulcanizing agents at about 0.2 to about 5 pllr For example, sulfur or peroxide-based curing systems may be employed. ~or a general disclosure of suitable vulcanizing agents one can refer to Kirk-Othmer, Encyclopedia of Chemical 20 Technolo~y, 3rd ed., Wiley Interscience, N.Y. 1982, Vol. 20, pp. 365-468, particularly "Vulcanization Agen~s and l~uxiliary Materials" pp. 390-402. Vulcanizing agents can be used alone or in combination.
Vulcanizable elastomeric compositions of lhe invention can be prepared by compounding or mixing ~he func~ionalized polymers herein Wi~ll carbon black, silica, 25 and other conventional rubber additives including for example, fillers, plasticizers, antioxidants, curing agents and the like using standard rubber mixing equipment and procedures. Such elastomeric compositions when vulcanized using convelltiollal ruhl-cr vulcanization conditions have reduced hysteresis p rollerties and are ~articularly adaptccl for use as tread rubbers for ~ires having reduced rolling resistance, or improved balance 30 of snow and ice traction and wet traction. In other words, these l-olymers used in the presence of silica filler provide for obtaining coml osi~ions for pneumatic ~ires and the like which compositions have improved reduced hysteresis, or highly balanced wettraction, rolling resistance, snow/ice trac~ion, and mechanical s~reng~h when compounded witl1 silica filler and vulcanized, in llle lire.
Gr,NrR~I, E~rr~ll\l~NT~I, In order to demonstrate lhe ~repa~ alion and properties of elastomeric compositions prepared according to tlle present invention, several diene elastomers were prepared according to llle above disclosure. Cyclic amine initiators were used ~n rornl 5 styrene butadiene rubber (SBR) formulations used in the preparation of silica rllled samples, and these samples were compared against control samples described hereinbelow. As noted above, various techniques known in the art for carrying out polymerizations may be used wilh the invelltive cyclic amille initialor-terltlina~or-silica filler combination, witllout departing from the scol~e of the l-resent invention.
The polymerizalions were carricd out as is well known in the art. At least one formulation was prepared according to the following procedure. The polymerizalioll was conducl in a jacketed stainless steel pressure reactor under a hlanket of dry nitrogen. The pressure in the reaclor was main~ained be~ween ~0 and 70 psi during ~he course of the polymeriza~ion. The reactor was first cllarged with a 24-26 wt% solutioll of butadiene in hexane. Following the addition of butadiene, a 33 wt% solulion of styrene in hexane was added. The monomer blend was agi~ated while the modirler and initiator components were added. The polymerization was initiated at or near room temperature. The temperature of the polylnerization was regulated such that the higllest temperature recorded during ~he polymeriza~ion was below 135~F.
The copolymers were stabilized with an antioxidant. The copolymers were isolated by adding the cemenls ~o an cxcess of isopropanol followed hy dmlll drying.
These copolymers were compounded in~o one of six formula~ions. The maitl rcinrorcillg filler in all of these formulations was silica, al~hougll carbon black was includcd in some samples. The formulations of the present invention are described in Table 11.
TA~L~ Il Cure Formulations for Experimental Compositions Sample No. A 13 C
Copolymer 75 75 75 Natural Rubber 25 25 25 Silica 50 30 60 Wax Carbon Black (I~AI~) - 35 6 Antioxidant 0.95 0.95 0.95 Aromatic Oil 15 6 4 Naphthenic Oil - 15 15 Silane Coupling ~gent - I 2 Stearic Acid 1.5 1.5 1.5 Sulfur cure package 4.3 4.85 5.25 Zinc Oxide 3 3 3 For the polymerization of Sample No. A, tlle modifier was added first, 20 butyllithium (BuLi) was added second and the secondary amines such as hexamethyleneimine was last. The butyllithium and secondary amine reacted in sitrl to form the lithium imide initiator, namely N-lithiollexallletllylelleimille. The exact amounts of monomer, iniliator and modifier used in these polymerization or reported in Table IIIA, and are compare(l with Example C-l through C-lll wherein only butyllithiuln 25 and a modifiler were used to prepare the polymer.
g702011 155 - 17 -~ ~ ~ ~ ~ O
3 ~ ~ ~
o~
n ~ ~ ~ ~
o o ~ ~ ~ ~ 2 00 m ~
~ ._ E ~ E
O E E .~ ~ ~ o v, ~ ~, ~ O
c ~
~3 m ~ ~! m ~ ~ m 3 ~ ~ ~ ~ ~ o ~ oo ~ ~ ~ q 'O O 00 ~n ~ g,~
o~~
~ o ~ ~ Z ~
~~ e e e O ~ b~
Z ~ ~ ~.. , "., ~o ~+~x~~ ~
o 'o :
~ o o TABLE IIIC
E~nple No. . C-1 1 C-2 2 C-3 3 ML(I +4) 90 88 86 85 92 102 tan ô at 7% strain (65~C) 0.053 0.055 0.046 0.053 0.066 0.051 % Rebound (65~C) 62 68 62 69 63 69 ~G' (65~C, MPa) 9.45 7.89 9.40 7.35 8.31 7.37 300% Modulus (psi) 753 824 814 894 736 893 - 'ax 536 526 497 517 580 523 Table IIIB further eharacteri%es tlle polymer as llrel-are(l all(l sho~ in l'ahle IIIA. Table IIIC shows various ~3hysieal l~roperties for eo l l~al ison purposes. Thus it will be appreciated that Examples 1 2 and 3 demonslrate embodimen~s of ~he ~re~ent invention wllile Examples C-l C-2 and C-3 provide eontrols for comr~arison of tlle 5 prior art. It can readily be recognized tllat tlle l~resen~ invention involving ~he preparation of a siliea-filled particularly amorpllous silica-filled elastomericcomposition utilized a cyclic amine initiator resull in a marked reductioll of hysteresis in the eured compounds. This is demonstraled in all of ~he inven~ive examples by ~he ~ G values.
Not all lilhium amine used as inilialors produee an elaslolller wi~ll redueed hysteresis for carbon blaek rllled rubber slocks it ean be eoneluded that tlle interactioll between the polymer amine functionality and the siliea fillers are some what different from the interactions between tlle polymer amine functionality and tlle carbon black fillers.
l~or ~he polymerizations for cure formulations B and C these polylllers where initiated with N-lithiohexametllyleneimine and tllen termillated or ended wi~h a tin coupler namely tin tetracllloride. I~t Ieast sample B was compoullded and eompared to a silica-rllled rubber stoek whiell ineluded a polymer lllat had only l een end-lillke(l by tin tetraehloride and whiell ineluded full levels of a silane couplillg agenl (3 r~llr) as 20 compared to the presen~ inven~ion whicll included a reduced level of silane eollplillg agen~ (1 phr) ~he weigh~ ratio of lhe functional polymer ~o silica in ~he formula~ion was main~ained at about 2:1 al~hollgh ranges about 0.25/1 ~o 5/1 maybe sui~able. Table IV
provide the physical properlies of tlle compositions of the llresent inven~ioll (Examl-le 4-6) as compared to a con~rol composition having a full level of silane eoupling agen~
25 (C-4). The resulls aehieved in the composition of the l-resent inven~ion can be summarized in the hysteresis properties Ieplesen~e(l in Tal-le IV hy tan ~ at 50~C an(l in the tire da~a by rolling loss tlle wear resis~ance ShOWIl ill ~he Tahle IV by ~he Lambourn abrasion indiees and in llle tire data and the wet and dry trae~ioll Of lhe compounds. These results are listed in Table IV hereinbelow.
T,~nl,E IV
Example No. C-4 4 5 6 I~unctionality BuLi/Sn I-lMI/Sn IlMI/Sn I~MI/Sn Formulation (Table Il) B B B C
Additive (phr) silane/3 silane/l silane/l silane/2 ML4/130~C 57 59 53 59 Stress Strain 25~C
50% Modulus (psi) 210 190 180 211 300% Modulus (psi) 1910 .1450 1770 1710 Tensile (psi) 2320 2080 2290 2350 Lambourn Abrasion 25% index 100 123 114 89 65% index 100 114 117 94 Dynastat M', 50~C (MPa) 6.6 7.4 5.7 18.8 tan ~ 0.109 0.119 0.09 0.086 M', 0~C (MPa) 9.1 10.9 7.8 26 tan ~ 0.183 0.211 0.173 0.143 Tire Data Rolling Loss Z9G (N)31.86 31.77 30.72 --Dry Traction 100 100 101 --Wet Traction 100 100 98 --Thus it should be evident tllat tl1e cyclic amine iniliators and process of the present invention are higllly effective in providing enhanced interactions between the polymer and silica fillers. Tl1e invention is particularly suited for the prepata~ion of vulcanizable elastomets for tires, but is nccessarily limited thereto.
Based upon the foregoing disclosure, il shollld now be al~l-alellt that thc usc of the cyclic amine initiators and process describcd herein will carry out ~he ohjects sct forth hereinabove. It is, tllcrerore, to be understood that any variations evidellt fall witllin the scope of the claimed invention and thus, the selection of specific component elements can be determined without departing from the spirit of the invention herein i 910~011155 - 22 -disclosed and described. Thus, the scope of tlle invention sl1all inclu~le all modirica~iolls - and variations that may fall witllin the scol~e of the at~ached claims.
The subject invention relates to the composilioll of silica and aniollically polymerized diene polymer and copolymer elastomers. More specifically, tlle p resent invention relates to anionic polymerizalion employing lilhium amille inilia~ors an(l various terminator compounds providing improved dispersion of silica in elastomeric compounds.
Silica filled compounds which include these functional diene polymers and copolymers prepared according to tl1e present invention, llave reduced llysleresis characteristics and improved balance of hysteresis properties with wet traction or snow and ice traction. Articles such as tires, power belts and the like, are typical applications with tires being particularly preferred.
I~ACKGROUND OF T~IE INVI~NTION
In the art it is desirable to produce elastomeric compounds exhibiting reduced hysteresis when properly compounded with other ingredients such as reinforcil1g agcnts, followed by vulcanization. SUCII elaslomers, w!len compounded, fabricalcd and vulcanized into components for constructing articles such as tires, power belts, and the like, will manifest properties of increased rebound, decreased rolling resistance and less hcat-build up when subjected to mechanical stress during normal use.
The llystcresis of an elaslomeric compound rerers to the differel1ce bctwccll the energy applied to deform an article made from the elastomeric compound and the energy released as the elastomeric compound returns to its initial, ullderormc(l sla~e.
In pneumatic tires, lowered hysteresis properties are associated with rcdllced rolling resistance and heat build-up during operation of the tire. These properties, in tum, result in such desirable characteristics as lowered fuel consumption of vehicles using sucll tires.
In such contexts, the property of lowered hysteresis of compoul1ded, vulcanizable elastomer coml~ositions is particularly signirlcant. Examplcs of sllcll compounded elastomer systems are kno~vn to the art and are comprised of at least one elastomer (that is, a natural or syntlletic polymer exhibiting elastomeric properties, such 9702011 1s5 - 2 -as a rubber), a reinforcing filler agent (such as finely divided carbon black, lherl1lal black, or mineral fillers such as clay and the like) an~ a vulcanizing sys~eltl ~uch as sulfur-containing vulcanizing (that is, curing) system.
Previous atteml~ts at l-rel-aring reduced hysteresis r~roducls have foc1lsc(1 ul~oll increased interaction between tlle elastomer and tlle COlllpOU11(3illg materials SUCIl as carbon black, including high temperature mixing of the filler-rubber mixtures in the -resence of selectively-reactive l-romoters to promote coml~ounding material rcinforcement, surface oxidatioll of the coint~oundillg materials, chemical mo(lirlcatiolls to tlle terminal end of l~olymers USillg 4,4'-bis(dimetllylamino)benzopllellolle (Miclller's ketone), tin coupling agents and tllc like and, surface graf~ g.
Various organolithium polymerization ini~iators are also known in tlle art.
U.S. Pat. No. 3,439,049, owned by tlle Assignee of record, discloses an organolithiu initiator prepared from a halophenol in a llydrocarbon mediuln.
U.S. Pat. No. 4,015,061 is directed toward amino-functional initiators wllich polymerize diene monomers to fontl mono- or di-l~rimary aryl amille-lerlllillatcd dielle polymers ur~on acid hydrolysis. U.S. Pat. No. 4,914,147 discloses terminal modifyillg agents including dialkylamino-substituted aromatic vinyl com~ounds such as N,N'-dimethylamino benzo~henone and p-dimetllylamino styrene, in rubber coml~ositionshaving reduced hysteresis characteristics. In U.S. ~'at. No. 4,894,409, an amino groull-containing monomer, such as 2-N,N-dimethylaminostyrene is ~olymerized to form anamino group-containing diene based l-olymer.
Other r~atents owned by the assignee of record, directed to aminc-contaillillg r)olymerization initiators and terminators include U. S. Patellt Nos. S,238,893;5,274,106; 5,329,005; 5,332,810; 5,393,721; 5,496,940; 5,508,333; 5,519,086;
5,521,309; 5,523,371; and 5,552,473. Lawson, et al., in A~1ioniC Pol~mer-iz-7~iort ~f Dienes Usirlg l~orrloger1eol~s lit~ rrl Arrli~e (N-Li) Ini~ )r.s ACS l'rc~-rillt, I'olynlcr Division, 37 (2) 1996, at l-age 728, disclosed that, for call~ lack-fillcd COltll~OInl(lS, cyclic amino lithium initiators of a certain size l-rovided elastomeric comlnolmds exhibiting reduced hysteresis.
Precipitatcd silica has been increasillgly use(l as a reinforcing l-articula~c filler in rubber comllonents of tires and mechanical goods. The reason silica is used in tires is that silica allows one to iml~rove tlle l-erformance halance between wet tractio n and rolling resistance, snow/ice traction and, mechanical properties such as wear 9702011 155 _ 3 - performance. Silica-loaded rubber stocks, however, have heretofore exhibited relatively poor resilience and high compound viscosity when used witllout any silane-coupling agent wllicll is somewllat expensive to be widely used in the industry. Even witll a certain amount of silane-coupling agent, total balance of the foregoing performances was 5 often not sufficient.
The present invention provides initiators for anionic polymerization whicll become incorporated into t}le elastomer chain, as well as various tenninators for the polymerization, and produce functional groups wllicll greatly improve the dispersability Or silica filler lhrougllout the elaslomeric composilion during compoullding. As will l)c 10 described hereinbelow, these initiators contain amine groups.
This invention utilizes a combination of silica and polymer with amille prodllcing initiators to increase dispersion of silica rlller in diene polymer and copolymer elastomeric compounds, and to thereby reduce tlle hysteresis of the cured compounds or improve mechanical properties through the interaction (reinforcement) between silica 15 and amine functionalities of the polymer. By this one could even reduce the amount of expensive silane-coupling agent.
SUMMARY OFINVENTION
It is therefore an object of the present invention to provi(le anionic 20 polymerization initiators and terminators WlliCIl improve the dispersion or reinforcement of silica filler in diene polymer elastomers.
It is another object of the present invention to provide a method for reducing thc hysleresis of siliGa-fillc(l elastonleric vulcanizal-le coml-ollnds.
It is anotiler objecl of the presellt invention to provide vulcanizable silica-25 filled elastomeric compounds, which upon vulcanization, exllibit reduced hysteresis.
It is still another object of the present invention to provide an imllrovedpneumatic tire having decreased rolling resistance.
- It is yet another object of the present invention to provide an improved pneumatic tire having improved balance of wet traction, snow and ice traction, 30 hysteresis properties and mechanical strength.
At least one or more of the foregoing objects, together with the advantages thereof over the existing art, whicll shall become apparent from the specirlcation whicl follows, are accomplished by the invention as hereinafter described and claimed.
- ~702011 155 , _ 4 The present invention provides a process for ~he production of diene-based elastomeric compositions having improved reduced llysteresis, or lligllly balanced wet traction, rolling resistance, snow/ice traction, and mechanical strengtll wllen compounded with silica fller and vulcanized, tlle process coml-rising mixing a diene S monomer and optionally a monovinyl aromatic monomer or a triene with a litllhllll amine initiator compound optionally in the presence of a modirler, wherein tlle li~llium amine initiator compound is selected from the group consisting of compounds of the formulas R'-N-Li and R'-N-R"-Li wherein R' is a cyclic anlille group havillg 3 to 18 ring carbon atoms and, togetller wilh the nitrogen, a ring or 4 to 19 atollls, and whereill 10 R" is a divalent llydrocarbyl group of 2 to 20 carbons, wherein tlle litllium a~om is not bonded to a carbon whicll is directly bomled to tl~e anlille nitrogell; crrectil~g polymerization conditions; terlllinatillg polymerization wi~ll a ter~ la~ing agellt to ron a functionalized diene elastomer; compounding the functionalized diene elastomer witll an amorphous silica filler, and a vulcanization agent; and, efrec~ing vulcaniza~ion or tlle 15 silica filled, functionalized diene filled elastomeric compound.
l lle present invention further provides a vulcanizable silica-filled COml~OUIl(l comprising a diene elastomer containillg a lithiulll amille ini~iator-(lerived func~iol1ali~y and a functionality derived from a terminator, a silica filler, and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of a litllium amine 20 initiator derived from a reaction of a secondary amine with a hydrocarbyl li~hium and of the formula R'N-Li, wherein R' is a cyclic anline group having 3 to l8 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 alollls.
The present invention still fur~her llrovides a vulcanizable silica-filled coml~ound comprisillg a diene elastomer contaillillg a lithiulll amille ini~ia~or-(lerive(l 25 functionality and a functionality derived from a terminator, a silica filler, and a vulcanization agent, whereill tlle lithium amine initiator-derived fullc~ionali~y is a residue of a lithium-hydrocarbon substituted tertiary amine of the formula initiator derived from a reaction of a secondary amille wi~h a hydrocarbyl lithiulll an~l of ~he rolmula R'N-R"-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, tnge~her 30 wi~ll the nitrogen, a ring of 4 to 19 atoms, and whereill R" is a divalen~ hy(lrocarhyl group of 2 to 20 carbons and the lithium atom is not bonded to a carbon wllicll is directly bonded to the amine nitrogen.
97n2011155 - 5 -The present invention fur~her provides a vulcanizable silica-filled compound comprising a diene elastomer containing a li(hium amine ini~ia~or-derived functionali~y and a functionality derived rrom a terminator, the termillator heing devoid or an alkoxysilane group; a silica filler; and a vulcanizatioll agent, whereill ~he lithilllll anlillc 5 initiator-derived functionality is a residue of an initiator derived or the rnrmula R'-N-R"-r-Lit wllerein R' is a cyclic amille group having 3 to 18 ring carbon atnms an(l, logcthcr with the ni~rogen, a ring of 4 to 19 a(oms, wherein R" is a divalent llydrocarbyl groul-of 2 to about 20 carbons and whereill 1~ is a diene-type oligomer having from I to abou~
100 diene monomer units; wherein tlle dicne monc)mer is isoprelle or 1,3-bula(3iclle.
DETAILED DESCRIrTION OF TIIE rREFERREI) ~ OI)I~ENTS
In general, the present invention provides the obtainment Or cllllallcccl polymer filler interactions Witll silica, thereby providillg vulcanizable elastomers ror tlle manufacture of articles SUCll a pneumatic tires having iml-roved reduced hysteresis, or 15 highly balanced wet trac~ion, rolling resistance, snow/ice traction, and mecllallical strength. This is accomplished by the use of cyclic amillo con~aining ini~iators (i.e., li~hium amine ini~iators) and, prererably, amino group producitlg terminators. 13y "amino group producing terminator" is meant a nitrogen containing precursor compound which acts as a terminator for a "living" diene polymer, and wllicll arter terll-illation, 20 contains or provides an amino group to form an amine runctionalized diene elastomer.
Such a combination of both cyclic amino contailling initiators and amillo groul-producing termina~ors has the advanlage lhal tllc iniliatioll will put a reactive gro~ On almost all of ~he polymer chains and ~hen any addi~ional end capring during tenllinalion will give polymers having an increased level of reactivity towards silica rlller when 25 compared to conventionally inilialed polymers modiried only by termination.
The li~hium amine initia~ors used in ~he presell~ inven~ion include li~hiuln imides wherein a lithiulll atom is direclly bonded to the nitrogell Or a sccondary amille or (lithium-llydrocarbyl) substitu~ed amine wherein the lithiullt alom is directly bollded to a carbon wllicll is part of a hydrocarbyl group wllicll, in turn, is bonded to a nitrogell.
30 Representative of the rormer (i.e., li~hium bondcd ~o ni~rogen) are coml-ollllds Or ~lle structural rormula R'N-Li, and or the la~ter (i.e., lilhi~ bollde(l to a carlon~, compounds of the structural formula R'N-R"-Li, whereill each R' in ei~her forlllula is a part oF a cyclic amine group, bonded toge~her witll the nilrogen and the olher R', and 97~2011155 - 6 -R" is a divalent hydrocarbyl group, preferably havillg 2 to 20 carbons. More particularly, the two R' groups may be bonded together to rorm, with the nitrogen, a cyclic amine group preferably having 3 to 18 ring carbon atoms and, together with tlle nitrogen, prererably a ring of 4 to 19 atoms. An example of this cyclic amine group is a cyclic methylene ring of 4 to 18 methylene groups. It will be appreciated the R" may furtl1er include additional non-hydrocarbyl components within the structural rormula.
~or example, R" may include morpholine or alkyl piperazine. In the la~ter romlula, it will be appreciated that the lithium atom is preferably not honded to a carbon whicll is directly bonded to the amine nitrogen, but ratller, is separated by at Ieast one, and more 10 preferably, at least 3 carbon atoms.
The lithiuln anline initiators according lo lhe presellt invell~ion, are enlploye(l to prepare any anionically-polymerized elastomer, e.g., polyhutadiene, polyisoprelle an~
the like, and copolymers thereof with monovinyl aromatics sucll as styrene, alplla metllyl styrene and the like, or trienes such as myrcene. Thus, tlle elastomers include diene 15 homopolymers, A, and copolymers thereof with monovil1yl aromatic p01ylllers, B.
Exemplary diene homopolymers are those prepared from diolerln monomers havillg fronl 4 to about 12 carbon atoms. Exemplary vinyl aromatic polyl1lers are lhosc prel-ared from monomers having from 8 to about 20 carbon atorns. Examples of conjugated diene monomers and the like userul in tlle present invention include 1,3-butadiene, isoprelle, 20 1,3-pentadiene, 2,3-dimetllyl-1,3-butadiene and 1,3-hexadiene, and aromatic vinyl monomers include styrene, ~x-metllylstyrene, p-llletllylstyrene, vinyltoluelles all(l vinylnaphtalenes. The conjugated diene monomer and aromatic vinyl monomer are normally used at tlle weigllt ratios of ahout 90/10 lo about 55/45, prererahly abollt 80/20 to about 65/35.
rreferred elastomers include diene homopolymers such as polybutadiene and polyisoprene and copolymers such as styrene butadiene rubber (SBR). Copolymers can comprise from about 99 to 55 percent by weight of diene ullits and from al-out I to about 45 percent by weight of monovinyl aromatic or triene units, totaling tO0 percent.
The polyl1lers and copolymers Of the presellt inventioll may have the (liene pO~ ll witll 30 a 1,2-microstructure contents ranging from about 10 to about 80 percent, with the preferred polymers or copolymers having 1,2-microstructure contents of frolll al~out 12 to about 65 percent. The molecular weight of the polymer lhat is produced according to the present invention, is preferably such that a proton-quenched sample will exhibit - 970201 1 ~55 _ 7 a gum Mooney viseosity (ML4/212~F) of from about 10 to about 150. The copolymersare preferably random eopolymers whieh result from simullaneous copolymerizalion Or lle monomers, as is known in the art.
The initiators eontaining eyelie amines, aeeording to the present inventioll, 5 preferably include N-lithiollexamethyleneimide, hexametllyletleiminoprol~yllillliurn, and lithiated adduets of eyelie amines, such as adducts of hexamelllyleneill1ine wi~h 1,3-butadiene, isoprene, 1-3-diisopropenylbenzene and ortho-xylene.
Still other lithium amine initiators include those compounds of the structural formula R'N-R"-P-Li, wherein R' is again a cyclic amine group having 3 to 18 ring 10 earbon atoms and, ~oge~her wi~h tllC nilrogen, a ring Or 4 ~o 19 alom.s, 1~" is agaill a divalent hydrocarbyl group of 2 to 20 earbons, and P is a diene - type oligomer having I to 100 diene monomer units. Preferably, the diene mollomer is selec~ed from ~lle group eonsisting of isoprene or 1,3-butadiene. It will be ar~preciated llla~, wllile oligomers typieally do not include more than about 50 monomer units, ~he word 15 "oligomer" has been used in tllis instance to denoted the p otential strueture as having up to about 100 monomer units.
Polymerization is usually conducted in a convenlional solvent for anionic polymerizations such as tlle various eyelie and acyclic hexanes, llelltalles, octalles, pentanes, their allcylated derivatives, and mixtures thereoF, as well as aromalic solvellls 20 such as benzene, t-butylbenzene, toluene, and the like. O~her lechlliques forpolymerization, such as semi-batch and continuous polymerization may be employed.
In order to promote ran(lomization in copolymerization an(l to increase vinyl content, a modifer may optiollally be added to tlle polymerization ingredients. I~mollllts range between 0 to 90 or more equivalent.s per equivalellt of litlliuln. l'he anl(Illllt depell(l~s 25 upon the amount of vinyl desired, the level of styrene employed and the temperature of the polymerizations, as well as the nature of the specific polar coordinator (modifier) employed.
- Compounds useful as modifiers are organic an(l include those havillg all oxygen or ni~rogen he~ero-a~om and a non-bonded pair of electrons. Examples include 30 dialkyl e~hers of mono and oligo alkylene glyeoLs; "crown" e~hers; tertiary amille~s SllCh as tetramethylethylene diamine (TMED~); TIJ~; Tll~ oligomers; linear and eyelic oligomeric oxolanyl alkanes, such as 2-2'-di(tetrahydrofuryl) propane, di-piperidyl ethane,hexamethylphosphoramide, N-N'-dimethylpiperazine,diazabicyclooctalle,dietllyl etller, tributylamine and the like. Details of linear and cyclic oligomeric oxolanyl modirlers can be found in U.S. rat. No. 4,429,091, owne~ by tlle ~ssignee of record, the subject matter of whicll is incorporated herein by reference.
Polymerization is usually begun by cllarging a blend of the mollolller(s) and S solvent to a suitable reaction vessel, followed by the addition of the modifier an(l the initiator. ~Iternatively, the monomer and modifier can be added to the initiator. The procedure is carried out under anllydrous, anaerobic conditiolls. The teaclall~s are lleated to a temperature of from about 10~ to about 150~C all(l are agilated ror al-ollt 0.1 to 24 hours. After polymerizatioll is complete, the product is removed from the heat 10 and terminated in one or more ways.
To terminate the polymerization, a terminating agent, couplillg agent or linking agent may be employed, all of these agents being collectively referred to herein as "terminating agents". Certain of these agents may provi(le the resulting polylller wi~h a multifunctionality. That is, the polymers initiated accordillg to the present invelltioll, 15 carry at least one amine functional group as discussed hereillabove, and may also carry a second functional group selected and derived from the groul7 consisting of terminating agents, coupling agents and linking agents.
According to the present invention, useful terminating, coupling or linking agents include an amino producing group, exemplirled by but not limiled to llle 20 following: 4,4'-bis(dialkylamino)benzopllenolle (such as 4,4'(dimetllylalllinn)-benzophenone or the like); N,N-dialkylamino-benzaldehyde (such as dime~hylalllillo-benzaldellyde or tlle like); 1,3-dialkyl-2-imidazolidillolles (sucll as 1,3-(linlelllyl-2-imidazolidinone or the like); I-alkyl subsliluled pyrrolidinones; I-aryl suhslilu~e(l pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about S to about 20 25 carbon atoms;
R2--N~N - R2 9702011155 _9 _ N~CH=O
~\N--R2 / N~\O~N=CH--R3 ~5 and, / N~ CH=N--~5 ;
wherein each R2 is the same or different and is an alkyl, cycloalkyl or aryl, having from I to abou( 12 carbon atoms. ~or examl-le, R2 tnay include mc~hyl, clh nonyl, t-butyl, phenyl or the like.
R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophellyl, having frolll I
to about 20 carbon atoms. ~or example, R3 may include ~-b-l~yl, 2-mctllyl-4-1-ell~ene-2-yl, phenyl, p-tolyl, p-butylphenyl, p-dodecylphenyl, p-dietllyl-alllino~llenyl, p-(pyrrolidino)phenyl, and the like.
Each R4 is tlle same or differen~, and is an alkyl or cycloalkyl havill~ fr 1 lo about 12 carbon aloms. Two of ~hc R4 groups may ~ogetller ~orm a cyclic ~ro~
For example, R4 may include methyl, ethyl, octyl, tetramethylene, pentametllylene, cyclohexyl or the like.
9702011 155 _ 1O _ - Rs may include alkyl, phenyl, alkylphenyl or dialkylaminop11enyl, llaving from I to about 20 carbon atoms. ~:or example, Rs may include me~hyl, butyl, phenyl, p- butylphenyl, p-nonylphenyl, p-dimethylaminol~hellyl, p-diethylaminol~lleIlyl, p-(piperidino)phellyl, or the like.
Olller useful terminating agents may include lhose of the slructural fonllula (Rl)a ZXb, wherein Z is tin or silicon. It is preferred that Z is tin, and when it is, Rl is an alkyl having from I to about 20 carhon atoms; a cycloalkyl havillg frolll al-out 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20 carbon aloms. ~or example, Rl may include me~hyl, e~hyl, n-butyl, neophyl, pllenyl, cyclollexyl or the like. When Z is tin, X is a halogen such as chlorille or hrnmille, or an alkoxy, "a" is froln 0 lo 3, an(l "b"
is from about I to 4; where a + b = 4. Examples of such terminatillg a~en~s inclll(le tin tetracllloride, (Rl)3SnCI, (Rl)2SnC12, RISnCl3, RISn(ORl)3 and (Rl)2Sn(OR)2.When Z is silicoll, tllen Rl is again an alkyl having from I to 20 carbo a~oms, a cycloalkyl having from abou~ 3 to about 20 carbon atoms; an aryl havillg fronl about 6 to about 20 carbon atoms; or, an aralkyl havillg from about 7 to about 20 carbon a~oms. Tha~ is, Rl, may again be methyl, ethyl, n-bu~yl, nenl hyl, r~hellyl, cyclohexyl or tlle like. X in tlle formula provided hereinabove is only a halogen, SIICIl as chlorine or bromine when Z is silicon. Tha~ is, alkoxysilanes, Si(OR)x wllerein R
is an alkyl, cycloalkyl, aryl, or aralkyl, are particularly exclude(l. In fact, it is preferre(l tha~ the terminating agent be devoid of any alkoxysilane groups. Examples of desirahle terminating agents include RISiC13, (Rl)2SiC12, (Rl)3SiCI and silicon tetrachlori(le.
Examples of additional terlnilla~ing agellts include water, s~ealll, an alcohol such as isopropanol, carbodiimides, N-methylpyrrolidine, cyclic amides, cyclic ureas, isocyanates, Schiff bases, 4,4'-bis(diethylalllino) benzol-llenone, and the like.
The tenllinating agent is added to the reac~ion vessel, an(l ~he vessel is agitated for about I to about 1000 minutes. /'~s a reslllt, an elastomer is pro(lllced llaving an even greater affinity for silica compounding materials, and hellce, even further reduced hystercsis. ~dditional examllles of temlinalillg agellts inclllde ~llose found in U.S. ~atent No. 4,616,069 whicll is hereill incorl-orate(l hy rercrence. 1~ is lo be understood tllat practice of tlle l~resent inventioll is not limited solely to tllese terminators inasmucll as other compounds that are reac~ive witll the r~olymer holllld litllium moiety can be selected to provide a desired functional group.
970~ 55 ~ Quenchillg is usually conducted by stirring the polymer and quenching agent for about 0.05 to about 2 llours at temperatures of from about 30~ to 120~ C to ensure complete reaction. Polymers terminated with a fimctional group as discIlssed hereinabove, are subsequently quenched with alcohol or other quenclling agent as5 described hereillabove.
Lastly, the solvent is removed rrom the polylller b y conventiollal techlliques such as drum drying, extruder drying, vacuum drying or the like, whicll may be combined wi~h coagulation with water, alcohol or steam, thermal desolventization, or any other suitable melhod. If coagulation with water or steam is used, oven drying may I0 be desirable.
The functional group or groups contained in the elastomer of this inveIltioll have an affinity for silica. Such compounding results in products exhibitirlg reduced hysteresis, which means a product having increased rebound, decreased rolling resistance and having lessened heat build-up when subjected to mechanical stress or I5 higllly balanced wet traction, rolling resistance, snow/ice traction and mecllaIlical strength. Products including tires, power belts and the like are envisioned. Decreased rolling resistance is, of course, a useful property for pneumatic tires, both radial as well as bias ply types and thus, the vulcanizable elastomeric compositions of the l7resent invention can be utilized to form treadstocks for such tires.
The polymers of the present invention can be utilized as 100 parts or the rubber in the treadstock compoIlnd or, tlley can l e blellded with any cnnvelltiollally employed treadstock rubber whicll inclu(les natural rubber, sylltlletic mhber and l-lellds tl1CreOf. SUCII rubbers are well known to tllose skilled in the art and include syntlletic polyisor~rene rubber, styrene/butadielle nlbber (S13R), I-olyblltadielle, hlltyl tul-l-cr, neoprene, ethylene/propylene rubber, ethylene/propylelle/dieIle rubber (ErDM), acrylonitrile/butadiene rubber (NBR), silicone rubber, the fluoroelastomers, ethylelle acrylic rubber, ethylene vinyl acetate copolymer (EVA), epichlorollydrin rubbers, chlorinated polyethyleIle rubbers, chlorosulrollated l~olyelhylene rubhers, hs~drogen~ed nitrile rubber, tetratluoroethylene/propyleIle rubber and the like. Whell the polylllers or the present invention are blended with convelltional nlhbers, the al~ s Call vary widely in a range comprising about 10 to about 99 percent hy weight Or the ~o~al rubber.
It is to be appreciated that the minimum amount will depend primarily ul-on the degree of reduced hysteresis or performance balance that is desired.
97mO11 155 - 12 -- Aecording to the present invention, amorphous siliea (silicon dioxide) is utilized as a rlller for tlle elastomer. Silicas are generally classed as wet-l~rocess, hydrated silicas because they are l~roduee(l by a ehemieal reaetinn in water, frotll wllicll tlley are preeipitated as ultrafine, spherical partieles. Silica filler llas foulld limited use 5 in the past, however, because it is acidic in nature and interferes witll the cure process.
Compensation for this phenomenon has been required.
These ~rimary l~articles strongly associate into aggregates, whicll in turn combine less strongly into agglomerates. The surface area, as measured by the BEI
mclllo(l giVCS lhe besl measure of llle reinrorcillg characler Or ~lirrerellt silic.ls. I or 10 silicas of interest for tlle present invention, tlle surface area ~lloul(l be about 32 to about 400 m2/g, with tlle range of ahoul lO0 lo about 250 nl2/g heing ~referre(l, an(l lhe range of about 150 to about 220 m2/g being most pre~erre(l. The ~ of tlle silica filler is generally about 5.5 to about 7 or slightly over, prererably ahout 5.5 to ahollt 6.8.
Silica can be employed in the amount of aboul I part to about lO0 par~s per 100 parts of polymer (pllr), preferably in an amoullt rrom ahout 5 to ahove 80 r~llr. Tlle userul upper range is limited by the high viscosity imr~arted by rlllers of this type. Some of the eommercially available silieas WhiCIl may he used inelude~ Sil~ 190, lli-Sil~
215, and l~i-Sil~ 233, produeed by P~'G Industries. Also, a number of useful eommereial grades of different silieas are available from De Gussa CorporatioIl, Rllolle 20 Poulene, an(l J.M. Iiuber Corpora~ion.
The polymers may also be eompounded witll all forms of carbon black in amounts ranging fron1 about 0 to about 50 parts by weight, per 100 parts of rubber (pllr), witll ICSS tllan aboul S pllr being prererred. l he carhon blacks may inclll(le any of lhe eommollly available, comlllereially-prodllee(l carh(lll blacks bu~ ~hose llaving a surfaee area (EMSA) of at least 20 m2/gram ancl more preferably at least 35 m2/gram up to 200 m2/gram or higller are preferre(J. Surfaee area values use(l in ~llis ar~l-licalinn are lhose (letermine~l by ASTM test D-1765 using llle celyltrime~llyl-amlllonilllll hromi(le (CTAB) technique. Among the useful carbon blacks are furnace black, cllannel blacks and lamp blacks. More specifically, examples of the carbon blacks include super abrasion furllace (SAF) blacks, higll al-rasion furllace (llAI~) blacks, fast e~msioll furnace (~EF) blacks, rlne furnace (FF) blacks, intermediate super abrasion filrnace (ISAI;) blacks, semi-reinrorcillg furllace (SRl~) hlacks, IllC(Iilllll l~rOCCSSillg ChallnCI
blacks, hard processing channel blacks and conducting cllannel blacks. Other carbon blacks which may be utilized include acetylene blacks. Mix~ures of two or more of tlle above blacks can be used in preparing the carbon black products of the invention.
Typical values for surface areas of usable carbon blacks are summarized in the TABLE
I hereinbelow.
- TA~LE I
Carbon Blacks ~STM DesignationSurface Area (m2/g~
(D-1765-82a) (D-37G5) N-l 10 126 N-339 . 9S
: N-550 42 The carbon blacks utilized in the preparation of the rubber compounds of the 15 inven~ion may be in pelletized form or an unpelletized tlocculent mass.
The reinforced rubber compounds can be cured in a convenlional manller with known vulcanizing agents at about 0.2 to about 5 pllr For example, sulfur or peroxide-based curing systems may be employed. ~or a general disclosure of suitable vulcanizing agents one can refer to Kirk-Othmer, Encyclopedia of Chemical 20 Technolo~y, 3rd ed., Wiley Interscience, N.Y. 1982, Vol. 20, pp. 365-468, particularly "Vulcanization Agen~s and l~uxiliary Materials" pp. 390-402. Vulcanizing agents can be used alone or in combination.
Vulcanizable elastomeric compositions of lhe invention can be prepared by compounding or mixing ~he func~ionalized polymers herein Wi~ll carbon black, silica, 25 and other conventional rubber additives including for example, fillers, plasticizers, antioxidants, curing agents and the like using standard rubber mixing equipment and procedures. Such elastomeric compositions when vulcanized using convelltiollal ruhl-cr vulcanization conditions have reduced hysteresis p rollerties and are ~articularly adaptccl for use as tread rubbers for ~ires having reduced rolling resistance, or improved balance 30 of snow and ice traction and wet traction. In other words, these l-olymers used in the presence of silica filler provide for obtaining coml osi~ions for pneumatic ~ires and the like which compositions have improved reduced hysteresis, or highly balanced wettraction, rolling resistance, snow/ice trac~ion, and mechanical s~reng~h when compounded witl1 silica filler and vulcanized, in llle lire.
Gr,NrR~I, E~rr~ll\l~NT~I, In order to demonstrate lhe ~repa~ alion and properties of elastomeric compositions prepared according to tlle present invention, several diene elastomers were prepared according to llle above disclosure. Cyclic amine initiators were used ~n rornl 5 styrene butadiene rubber (SBR) formulations used in the preparation of silica rllled samples, and these samples were compared against control samples described hereinbelow. As noted above, various techniques known in the art for carrying out polymerizations may be used wilh the invelltive cyclic amille initialor-terltlina~or-silica filler combination, witllout departing from the scol~e of the l-resent invention.
The polymerizalions were carricd out as is well known in the art. At least one formulation was prepared according to the following procedure. The polymerizalioll was conducl in a jacketed stainless steel pressure reactor under a hlanket of dry nitrogen. The pressure in the reaclor was main~ained be~ween ~0 and 70 psi during ~he course of the polymeriza~ion. The reactor was first cllarged with a 24-26 wt% solutioll of butadiene in hexane. Following the addition of butadiene, a 33 wt% solulion of styrene in hexane was added. The monomer blend was agi~ated while the modirler and initiator components were added. The polymerization was initiated at or near room temperature. The temperature of the polylnerization was regulated such that the higllest temperature recorded during ~he polymeriza~ion was below 135~F.
The copolymers were stabilized with an antioxidant. The copolymers were isolated by adding the cemenls ~o an cxcess of isopropanol followed hy dmlll drying.
These copolymers were compounded in~o one of six formula~ions. The maitl rcinrorcillg filler in all of these formulations was silica, al~hougll carbon black was includcd in some samples. The formulations of the present invention are described in Table 11.
TA~L~ Il Cure Formulations for Experimental Compositions Sample No. A 13 C
Copolymer 75 75 75 Natural Rubber 25 25 25 Silica 50 30 60 Wax Carbon Black (I~AI~) - 35 6 Antioxidant 0.95 0.95 0.95 Aromatic Oil 15 6 4 Naphthenic Oil - 15 15 Silane Coupling ~gent - I 2 Stearic Acid 1.5 1.5 1.5 Sulfur cure package 4.3 4.85 5.25 Zinc Oxide 3 3 3 For the polymerization of Sample No. A, tlle modifier was added first, 20 butyllithium (BuLi) was added second and the secondary amines such as hexamethyleneimine was last. The butyllithium and secondary amine reacted in sitrl to form the lithium imide initiator, namely N-lithiollexallletllylelleimille. The exact amounts of monomer, iniliator and modifier used in these polymerization or reported in Table IIIA, and are compare(l with Example C-l through C-lll wherein only butyllithiuln 25 and a modifiler were used to prepare the polymer.
g702011 155 - 17 -~ ~ ~ ~ ~ O
3 ~ ~ ~
o~
n ~ ~ ~ ~
o o ~ ~ ~ ~ 2 00 m ~
~ ._ E ~ E
O E E .~ ~ ~ o v, ~ ~, ~ O
c ~
~3 m ~ ~! m ~ ~ m 3 ~ ~ ~ ~ ~ o ~ oo ~ ~ ~ q 'O O 00 ~n ~ g,~
o~~
~ o ~ ~ Z ~
~~ e e e O ~ b~
Z ~ ~ ~.. , "., ~o ~+~x~~ ~
o 'o :
~ o o TABLE IIIC
E~nple No. . C-1 1 C-2 2 C-3 3 ML(I +4) 90 88 86 85 92 102 tan ô at 7% strain (65~C) 0.053 0.055 0.046 0.053 0.066 0.051 % Rebound (65~C) 62 68 62 69 63 69 ~G' (65~C, MPa) 9.45 7.89 9.40 7.35 8.31 7.37 300% Modulus (psi) 753 824 814 894 736 893 - 'ax 536 526 497 517 580 523 Table IIIB further eharacteri%es tlle polymer as llrel-are(l all(l sho~ in l'ahle IIIA. Table IIIC shows various ~3hysieal l~roperties for eo l l~al ison purposes. Thus it will be appreciated that Examples 1 2 and 3 demonslrate embodimen~s of ~he ~re~ent invention wllile Examples C-l C-2 and C-3 provide eontrols for comr~arison of tlle 5 prior art. It can readily be recognized tllat tlle l~resen~ invention involving ~he preparation of a siliea-filled particularly amorpllous silica-filled elastomericcomposition utilized a cyclic amine initiator resull in a marked reductioll of hysteresis in the eured compounds. This is demonstraled in all of ~he inven~ive examples by ~he ~ G values.
Not all lilhium amine used as inilialors produee an elaslolller wi~ll redueed hysteresis for carbon blaek rllled rubber slocks it ean be eoneluded that tlle interactioll between the polymer amine functionality and the siliea fillers are some what different from the interactions between tlle polymer amine functionality and tlle carbon black fillers.
l~or ~he polymerizations for cure formulations B and C these polylllers where initiated with N-lithiohexametllyleneimine and tllen termillated or ended wi~h a tin coupler namely tin tetracllloride. I~t Ieast sample B was compoullded and eompared to a silica-rllled rubber stoek whiell ineluded a polymer lllat had only l een end-lillke(l by tin tetraehloride and whiell ineluded full levels of a silane couplillg agenl (3 r~llr) as 20 compared to the presen~ inven~ion whicll included a reduced level of silane eollplillg agen~ (1 phr) ~he weigh~ ratio of lhe functional polymer ~o silica in ~he formula~ion was main~ained at about 2:1 al~hollgh ranges about 0.25/1 ~o 5/1 maybe sui~able. Table IV
provide the physical properlies of tlle compositions of the llresent inven~ioll (Examl-le 4-6) as compared to a con~rol composition having a full level of silane eoupling agen~
25 (C-4). The resulls aehieved in the composition of the l-resent inven~ion can be summarized in the hysteresis properties Ieplesen~e(l in Tal-le IV hy tan ~ at 50~C an(l in the tire da~a by rolling loss tlle wear resis~ance ShOWIl ill ~he Tahle IV by ~he Lambourn abrasion indiees and in llle tire data and the wet and dry trae~ioll Of lhe compounds. These results are listed in Table IV hereinbelow.
T,~nl,E IV
Example No. C-4 4 5 6 I~unctionality BuLi/Sn I-lMI/Sn IlMI/Sn I~MI/Sn Formulation (Table Il) B B B C
Additive (phr) silane/3 silane/l silane/l silane/2 ML4/130~C 57 59 53 59 Stress Strain 25~C
50% Modulus (psi) 210 190 180 211 300% Modulus (psi) 1910 .1450 1770 1710 Tensile (psi) 2320 2080 2290 2350 Lambourn Abrasion 25% index 100 123 114 89 65% index 100 114 117 94 Dynastat M', 50~C (MPa) 6.6 7.4 5.7 18.8 tan ~ 0.109 0.119 0.09 0.086 M', 0~C (MPa) 9.1 10.9 7.8 26 tan ~ 0.183 0.211 0.173 0.143 Tire Data Rolling Loss Z9G (N)31.86 31.77 30.72 --Dry Traction 100 100 101 --Wet Traction 100 100 98 --Thus it should be evident tllat tl1e cyclic amine iniliators and process of the present invention are higllly effective in providing enhanced interactions between the polymer and silica fillers. Tl1e invention is particularly suited for the prepata~ion of vulcanizable elastomets for tires, but is nccessarily limited thereto.
Based upon the foregoing disclosure, il shollld now be al~l-alellt that thc usc of the cyclic amine initiators and process describcd herein will carry out ~he ohjects sct forth hereinabove. It is, tllcrerore, to be understood that any variations evidellt fall witllin the scope of the claimed invention and thus, the selection of specific component elements can be determined without departing from the spirit of the invention herein i 910~011155 - 22 -disclosed and described. Thus, the scope of tlle invention sl1all inclu~le all modirica~iolls - and variations that may fall witllin the scol~e of the at~ached claims.
Claims (45)
1. A process for the production of diene-based elastomeric compositions having improved reduced hysteresis, or highly balanced wet traction, rolling resistance, snow/ice traction, and mechanical strength when compounded with silica filler and vulcanized, when compounded with silica filler and vulcanized, the process comprising:
Mixing a diene monomer and optionally a monovinyl aromatic monomer or a triene with a lithium amine initiator compound optionally in the presence of amodifier, wherein the lithium amine initiator compound is selected from the group consisting of compounds of the formulas R'-N-Li and R'-N-R"-Li wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 atoms, and wherein R" is a divalent hydrocarbyl group of 2 to 20 carbons, wherein the lithium atom is not bonded to a carbon which is directly bonded to the amine nitrogen;
effecting polymerization conditions;
terminating polymerization with a terminating agent to form a functionalized diene elastomer;
compounding the functionalized diene elastomer with an amorphous silica filler, and a vulcanization agent; and, effecting vulcanization of the silica filled, functionalized diene filled elastomeric compound.
Mixing a diene monomer and optionally a monovinyl aromatic monomer or a triene with a lithium amine initiator compound optionally in the presence of amodifier, wherein the lithium amine initiator compound is selected from the group consisting of compounds of the formulas R'-N-Li and R'-N-R"-Li wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 atoms, and wherein R" is a divalent hydrocarbyl group of 2 to 20 carbons, wherein the lithium atom is not bonded to a carbon which is directly bonded to the amine nitrogen;
effecting polymerization conditions;
terminating polymerization with a terminating agent to form a functionalized diene elastomer;
compounding the functionalized diene elastomer with an amorphous silica filler, and a vulcanization agent; and, effecting vulcanization of the silica filled, functionalized diene filled elastomeric compound.
2. A process as in claim 1, wherein R' is a cyclic methylene ring of 4 to 18 methylene groups.
3. A process as in claim 1, wherein R" is a C3-8 divalent alkylene wherein the nitrogen and lithium atoms are separated by at least 3 carbon atoms.
4. A process as in claim 1, wherein the lithium amine initiator is selected from the group consisting of compounds of the formulas R'N-(CH2)n-Li, (CH2)m N-Li and (CH2)m N-(CH2)n-Li, wherein R' is selected from the group consisting of a C6-12 aryl, or a C6-12 alkyl aryl group, wherein m is an integer from 4 to 18 and wherein n is an integer from 2 to 20.
5. A process as in claim 1, wherein the lithium amine initiator compound is selected from the group consisting of compounds of the formula R'N-R"-P-Li, wherein P
is a diene-lype oligomer having 1 to 100 diene monomer units, and wherein the diene monomer is isoprene or 1,3-butadiene.
is a diene-lype oligomer having 1 to 100 diene monomer units, and wherein the diene monomer is isoprene or 1,3-butadiene.
6. A process as in claim 1, wherein the lithium amine initiator is selected from the group consisting of N-lithiohexamethyleneimide, hexamethyleneiminopropyllithium, and lithiated adducts of cyclic amines.
7. A process as in claim 6, wherein the lithiated adducts of cyclic amines include adducls of hexamethyleneimine with 1,3-butadiene, isoprene, 1,3-diisopropenylbenzene or ortho-xylene
8. A process as in claim 1, wherein the terminating agent is devoid of any alkoxysilane groups.
9. A process as in claim 1, wherein the step of terminating employs an amino group producing terminator to form an amine functionalized diene elastomer.
10. A process as in claim 9, wherein the amino group producing terminator is selected from the group consisting of 4,4'-bis(dialkylamino)benzophenone;
N,N-dialkylamino-benzaldehyde; 1,3-dialkyl-2-imidazolidinones; 1-alkyl substituted pyrrolidinones; 1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms;
and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about20 carbon atoms.
N,N-dialkylamino-benzaldehyde; 1,3-dialkyl-2-imidazolidinones; 1-alkyl substituted pyrrolidinones; 1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms;
and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about20 carbon atoms.
11. A process as in claim 1, wherein the step of terminating employs a terminator having the structural formula, (R1)aZXb; wherein Z is tin; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20 carbon atoms; X is a halogen or alkoxy, a is an integer from 0 to 3, and b is an integer from 1 to 4, where a + b = 4.
12. A process as in claim 1, wherein the step of terminating employs a terminator having the structural formula, (R1)aZXb; wherein Z is silicon; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or,an aralkyl having from about 7 to about 20 carbon atoms; X is a halogen, a is aninteger from 0 to 3; and b is an integer from 1 to 4; where a + b = 4.
13. A process as in claim 10, including terminating polymerization with an additional terminator selected from the group consisting of water, steam, an alcohol, carbodiimides, N-methylpyrrolidine, cyclic amides, cyclic ureas, isocyanates, Schiff bases, 4,4'-bis(diethylamino) benzophenone, and mixtures thereof, whereineach R1 may be the same or different and is an alkyl, having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an arylhaving from about 6 to about 20 carbon atoms; or an aralkyl having from about 7 to about 20 carbon atoms.
14. A process as in claim 11, wherein each R1 may be the same or different and is methyl, ethyl, butyl, octyl, cyclohexyl, 3-phenyl-1-propyl, isobutyl, and mixtures thereof.
15. A process as in claim 1, wherein the silica filler has a surface area of about 32 to about 400 m2/g.
16. A process as in claim 1, wherein the silica filler has a pH in the range of about 5.5 to about 7.
17. A process as in claim 1, including compounding the amine functionalized diene elastomer with carbon black.
18. A vulcanizable silica-filled compound comprising a diene elastomer containing a lithium amine initiator-derived functionality and a functionality derived from aterminator, a silica filler, and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of a lithium amine initiator derived from a reaction of a secondary amine with a hydrocarbyl lithium and of the formula R'N-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and,together with the nitrogen, a ring of 4 to 19 atoms.
19. The vulcanizable silica-filled compound of claim 18, wherein the elastomer is selected from the group consisting of conjugated diene polymers and copolymers thereof prepared from monomers selected from the group consisting of monovinyl aromatic monomers and trienes.
20. The vulcanizable silica-filled compound of claim 18, wherein R' a cyclic methylene ring of 4 to 18 methylene groups.
21. The vulcanizable silica-filled compound of claim 18, wherein the lithium amine initiator is selected from the group consisting of N-lithiohexamethyleneimide, hexamethyleneiminopropyllithium, and lithiated adducts of cyclic amines.
22. The vulcanizable silica-filled compound of claim 21, wherein the lithiated adducts of cyclic amines include adducts of hexamethyleneimine with 1,3-butadiene, isoprene, 1,3-diisopropenylbenzene or ortho-xylene.
23. The vulcanizable silica-filled compound of claim 18, wherein the terminator is devoid of an alkoxysilane group.
24. The vulcanizable silica-filled compound of claim 18, wherein the terminator functionality is an amino containing functionality and the amino containing functionality is a residue of an amino group producing terminator is selected from the group consisting of 4,4'-bis(dialkylamino)benzophenone; N,N-dialkylamino-benzaldehyde; 1,3-dialkyl-2-imidazolidinones; 1-alkyl substituted pyrrolidinones;
1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms;
and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about20 carbon atoms.
1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms;
and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about20 carbon atoms.
25. The vulcanizable silica-filled compound of claim 18, wherein the terminator functionality is a residue of a terminator having the structural formula, (R1)aZX b;
wherein Z is silicon; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X is a halogen, a is an integer from 0 to 3, and b is an integer from about 1 to 4; where a + b = 4.
wherein Z is silicon; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X is a halogen, a is an integer from 0 to 3, and b is an integer from about 1 to 4; where a + b = 4.
26. The vulcanizable silica-filled compound of claim 18, wherein the terminator functionality is a residue of a terminator having the structural formula, (R1)aZX b;
wherein Z is tin; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X is a halogen or alkoxy, a is an integer from 0 to 3, and b is aninteger from 1 to 4, where a + b = 4.
wherein Z is tin; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X is a halogen or alkoxy, a is an integer from 0 to 3, and b is aninteger from 1 to 4, where a + b = 4.
27. The vulcanizable silica-filled compound of claim 18, wherein the silica filler has a surface area of about 32 to about 400 m2/g.
28. The vulcanizable silica-filled compound of claim 18, wherein the silica filler has a pH in the range of about 5.5 to about 7.
29. The vulcanizable silica-filled compound of claim 18, including compounding the amine functionalized diene elastomer with carbon black.
30. A pneumatic tire having decreased rolling resistance comprising tread stock vulcanized from the vulcanizable silica-filled compound of claim 18.
31. A vulcanizable silica-filled compound comprising a diene elastomer containing a lithium amine initiator-derived functionality and a functionality derived from aterminator, a silica filler, and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of a lithium-hydrocarbon substituted tertiary amine of the formula R'N-R"-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, together with the nitrogen, a ring of 4 to19 atoms, and wherein R" is a divalent hydrocarbyl group of 2 to 20 carbons and the lithium atom is not bonded to a carbon which is directly bonded to the aminenitrogen.
32. The vulcanizable silica-filled compound of claim 31, wherein the elastomer is selected from the group consisting of conjugated diene polymers and copolymers thereof prepared from monomers selected from the group consisting of monovinyl aromatic monomers and trienes.
33. The vulcanizable silica-filled compound of claim 31, wherein R' a cyclic methylene ring of 4 to 18 methylene groups.
34. The vulcanizable silica-filled compound of claim 31, wherein R" is a C3-8 divalent alkylene wherein the nitrogen and lithium atoms are separated by at least 3 carbon atoms.
35. The vulcanizable silica-filled compound of claim 31, wherein the lithium amine initiator is selected from the group consisting of N-lithiohexamethyleneimide, hexamethyleneiminopropyllithium, and lithiated adducts of cyclic amines.
36. The vulcanizable silica-filled compound of claim 35, wherein the lithiated adducts of cyclic amines include adducts of hexamethyleneimine with 1,3-butadiene, isoprene, 1,3-diisopropenylbenzene or ortho-xylene.
37. The vulcanizable silica-filled compound of claim 31, wherein the terminator is devoid of an alkoxysilane group.
38. The vulcanizable silica-filled compound of claim 31, wherein the terminator functionality is an amino containing functionality and the amino containing functionality is a residue of an amino group producing terminator is selected from the group consisting of 4,4'-bis(dialkylamino)benzophenone; N,N-dialkylamino-benzaldehyde; 1,3-dialkyl-2-imidazolidinones; 1-alkyl substituted pyrrolidinones;
1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms; and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms.
1-aryl substituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms;
and, wherein each R2 is the same or different and is an alkyl, cycloalkyl ar aryl, having from 1 to about 12 carbon atoms; R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; each R4 is the same or different, and is an alkyl or cycloalkyl having from 1 to about 12 carbon atoms; and wherein two of the R4 groups may together form a cyclic group; R5 may include alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms.
39. The vulcanizable silica-filled compound of claim 31, wherein the terminator functionality is a residue of a terminator having the structural formula, (R1)aZXb;
wherein Z is silicon; R1 is an alkyl having from about 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl havingfrom about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20 carbon atoms; X is a halogen, a is an integer from 0 to 3, and b is an integer from about 1 to 4; where a + b = 4.
wherein Z is silicon; R1 is an alkyl having from about 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl havingfrom about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20 carbon atoms; X is a halogen, a is an integer from 0 to 3, and b is an integer from about 1 to 4; where a + b = 4.
40. The vulcanizable silica-filled compound of claim 31, wherein the terminator functionality is a residue of a terminator having the structural formula, (R1)aZXb;
wherein Z is tin; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X ia a halogen or alkoxy, a is an integer from 0 to 3, and b is aninteger from 1 to 4, where a + b = 4.
wherein Z is tin; R1 is an alkyl having from 1 to about 20 carbon atoms; a cycloalkyl having from about 3 to about 20 carbon atoms; an aryl having from about 6 to about 20 carbon atoms; or, an aralkyl having from about 7 to about 20carbon atoms; X ia a halogen or alkoxy, a is an integer from 0 to 3, and b is aninteger from 1 to 4, where a + b = 4.
41. The vulcanizable silica-filled compound of claim 29, wherein the silica filler has a surface area of about 32 to about 400 m2/g.
42. The vulcanizable silica-filled compound of claim 31, wherein the silica filler has a pH in the range of about 5.5 to about 7.
43. The vulcanizable silica-filled compound of claim 31, including compounding the amine functionalized diene elastomer with carbon black.
44. A pneumatic tire having decreased rolling resistance comprising tread stock vulcanized from the vulcanizable silica-filled compound of claim 31.
45. A vulcanizable silica-filled compound comprising a diene elastomer containing a lithium amine initiator-derived functionality and a functionality derived from aterminator, the terminator being devoid of an alkoxysilane group; a silica filler;
and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of an initiator derived of the formula R'-N-R"-P-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 atoms, wherein R" is a divalent hydrocarbyl group of2 to about 20 carbons and wherein P is a diene-type oligomer having from 1 to about 100 diene monomer units, wherein the diene monomer is isoprene or 1,3-butadiene.
and a vulcanization agent, wherein the lithium amine initiator-derived functionality is a residue of an initiator derived of the formula R'-N-R"-P-Li, wherein R' is a cyclic amine group having 3 to 18 ring carbon atoms and, together with the nitrogen, a ring of 4 to 19 atoms, wherein R" is a divalent hydrocarbyl group of2 to about 20 carbons and wherein P is a diene-type oligomer having from 1 to about 100 diene monomer units, wherein the diene monomer is isoprene or 1,3-butadiene.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/893,868 US5866650A (en) | 1997-07-11 | 1997-07-11 | Composition of cyclic amine-initiated elastomers and amorphous silica and process for the production thereof |
| US08/893,868 | 1997-07-11 |
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|---|---|
| CA2242797A1 true CA2242797A1 (en) | 1999-01-11 |
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|---|---|---|---|
| CA002242797A Abandoned CA2242797A1 (en) | 1997-07-11 | 1998-07-10 | Composition of cyclic amine-initiated elastomers and silica and process for the production thereof |
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| Country | Link |
|---|---|
| US (1) | US5866650A (en) |
| EP (1) | EP0890586B1 (en) |
| JP (2) | JPH11124475A (en) |
| CA (1) | CA2242797A1 (en) |
| DE (1) | DE69826188T2 (en) |
| ES (1) | ES2229420T3 (en) |
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| US5393721A (en) * | 1992-10-16 | 1995-02-28 | Bridgestone Corporation | Anionic polymerization initiators and reduced hysteresis products therefom |
| US5674798A (en) * | 1992-10-16 | 1997-10-07 | Bridgestone Corporation | Hydrocarbon soluble anionic polymerization initiators |
| ES2110557T3 (en) * | 1992-10-30 | 1998-02-16 | Bridgestone Corp | SOLUBLE ANIONIC POLYMERIZATION INITIATORS AND PRODUCTS OF THOSE. |
| JPH06279620A (en) * | 1993-03-26 | 1994-10-04 | Bridgestone Corp | Conjugated diene-based rubber composition |
| JP3441201B2 (en) * | 1993-12-29 | 2003-08-25 | 株式会社ブリヂストン | Polymer and polymer composition thereof |
| JP3514824B2 (en) * | 1993-12-29 | 2004-03-31 | 株式会社ブリヂストン | Polymer and polymer composition thereof |
| ES2245339T3 (en) * | 1993-12-29 | 2006-01-01 | Bridgestone Corporation | POLYMERS AND COPOLYMERS OF DIES WITH AN ALCOXISILAN GROUP. |
| JPH07233285A (en) * | 1993-12-29 | 1995-09-05 | Bridgestone Corp | Rubber composition |
| US5491230A (en) * | 1993-12-29 | 1996-02-13 | Bridgestone Corporation | Anionic polymerization initiators containing adducts of cyclic secondary amines and conjugated dienes, and products therefrom |
| US5521309A (en) * | 1994-12-23 | 1996-05-28 | Bridgestone Corporation | Tertiary-amino allyl-or xylyl-lithium initiators and method of preparing same |
| US5496940A (en) * | 1995-02-01 | 1996-03-05 | Bridgestone Corporation | Alkyllithium compounds containing cyclic amines and their use in polymerization |
| US5574109A (en) * | 1995-02-01 | 1996-11-12 | Bridgestone Corporation | Aminoalkyllithium compounds containing cyclic amines and polymers therefrom |
| AT405285B (en) * | 1995-09-07 | 1999-06-25 | Semperit Ag | RUBBER BLEND |
| JPH0987426A (en) * | 1995-09-20 | 1997-03-31 | Bridgestone Corp | Production of rubber composition |
| US5866650A (en) * | 1997-07-11 | 1999-02-02 | Bridgestone Corporation | Composition of cyclic amine-initiated elastomers and amorphous silica and process for the production thereof |
-
1997
- 1997-07-11 US US08/893,868 patent/US5866650A/en not_active Expired - Lifetime
-
1998
- 1998-07-06 EP EP98112474A patent/EP0890586B1/en not_active Expired - Lifetime
- 1998-07-06 DE DE69826188T patent/DE69826188T2/en not_active Expired - Lifetime
- 1998-07-06 ES ES98112474T patent/ES2229420T3/en not_active Expired - Lifetime
- 1998-07-08 JP JP10207102A patent/JPH11124475A/en active Pending
- 1998-07-10 CA CA002242797A patent/CA2242797A1/en not_active Abandoned
-
2008
- 2008-07-07 JP JP2008177113A patent/JP5390799B2/en not_active Expired - Lifetime
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6180710B1 (en) | 1997-07-11 | 2001-01-30 | Bridgestone Corporation | Addition of salts to improve the interaction of silica with rubber |
| US6221943B1 (en) | 1997-07-11 | 2001-04-24 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
| US6228908B1 (en) | 1997-07-11 | 2001-05-08 | Bridgestone Corporation | Diene polymers and copolymers incorporating partial coupling and terminals formed from hydrocarboxysilane compounds |
| US6342552B1 (en) | 1997-07-11 | 2002-01-29 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
| US6348531B1 (en) | 1997-07-11 | 2002-02-19 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
| US6384117B1 (en) | 1997-07-11 | 2002-05-07 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
| US6384118B1 (en) | 1997-07-11 | 2002-05-07 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
| US6423781B1 (en) | 1997-07-11 | 2002-07-23 | Bridgestone Corporation | Elastomers having a reduced hysteresis via interaction of polymer with silica surfaces |
| US6525118B2 (en) | 1997-07-11 | 2003-02-25 | Bridgestone Corporation | Processability of silica-filled rubber stocks with reduced hysteresis |
| US6790889B2 (en) | 1997-07-11 | 2004-09-14 | Bridgestone Corporation | Processability of silica-filled rubber stocks |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5390799B2 (en) | 2014-01-15 |
| ES2229420T3 (en) | 2005-04-16 |
| JP2008260952A (en) | 2008-10-30 |
| DE69826188D1 (en) | 2004-10-21 |
| JPH11124475A (en) | 1999-05-11 |
| EP0890586A1 (en) | 1999-01-13 |
| DE69826188T2 (en) | 2005-10-20 |
| US5866650A (en) | 1999-02-02 |
| EP0890586B1 (en) | 2004-09-15 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |