CA2112003C - Process for the preparation of in situ dispersion of copolymers - Google Patents
Process for the preparation of in situ dispersion of copolymers Download PDFInfo
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- CA2112003C CA2112003C CA002112003A CA2112003A CA2112003C CA 2112003 C CA2112003 C CA 2112003C CA 002112003 A CA002112003 A CA 002112003A CA 2112003 A CA2112003 A CA 2112003A CA 2112003 C CA2112003 C CA 2112003C
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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
- C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
- C08F297/02—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type
- C08F297/04—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type polymerising vinyl aromatic monomers and conjugated dienes
Abstract
The present invention relates to a process for the dispersion copolymerization of 35 to 70% by weight of vinyl substituted aromatic monomer and 30 to 65% by weight of conjugated dime monomer comprising carrying out the copolymerization in a reaction mixture containing a liquid aliphatic hydrocarbon dispersing medium, an anionic catalyst system, and an "A" block of a copolymer dispersing agent, the dispersing agent having at least two polymer blocks wherein at least one of the polymer blocks is soluble in the dispersing medium and at least another of the polymer blocks is insoluble in the dispersing medium and is formed in situ.
Description
-'. . 2~1~0~~
FIELD OF THE INVENTION
1 . The present invention relates to an anionic styrene-butadiene 2 type rubber polymerization process conducted in a nonaqueous 3 dispersion utilizing butadiene-type and styrene-type monomers and 4 a dispersing agent formed in situ during polymerization.
BACKGROUND OF THE INVENTION
6 In many prior art nonaqueous dispersion polymerization 7 systems, organic dispersing medium have been utilized having poor '8 solvent properties for the polymer being produced. A dispersing 9 agent was therefore utilized in the organic medium in order to' disperse the polymer being formed throughout the medium. These 11 dispersing agents or dispersants were generally polymeric materials 12 such as block copolymers, random copolymers, or homopolymers as 13 described in U.S. Patent Nos. 4,098,980 and 4,452,960. .
14 Styrene-butadiene rubbers (SBR) have generally been prepared in solvents in which~SBR is soluble. However; only SBR's having a 16 styrene content of less than 35% are soluble in hexane or other 17 non-cyclic aliphatic solvents. These higher styrene content SBR
18 .polymers are not completely insoluble in the aliphatic solvents, 19 and, in fact, are highly swollen in these solvents. However, SBR's._.
having a styrene content greater than 35% necessarily'have been 21 polymerized in aromatic or cycloaliphatic solvents via solution 22 polymerization.
23 The applicant first determined that certain pre-made 24 dispersing -agents can be utilized to conduct the nonaqueous 2~~.~fjsJ~
1 dispersion polymerization production of SBR having a styrene 2 content greater than 35% by weight in aliphatic dispersing medium 3 such ~as.hexane. Although the dispersion process using a pre-made 4 dispersant works well, it has one~shortcoming from a practical or commercial scale up point of view. The dispersant must be prepared 6 separately and stored for subsequent use in the polymerization 7 process. Storage tank and transfer lines require a large capital 8 expenditure and the synthesis of the dispersant and transfer time 9 into the polymerization reactor results in higher production costs.
In these first dispersion SBR studies, a single d~iblock 11 polymer consisting of a short block (5%-10% of total polymer) of 12 hexane soluble polybutadiene and a long block (90%-95% of total) of 13 high styrene content SBR was prepared in the absence of a 14 dispersing agent. Synthesis of this polymer structure in hexane resulted in either extremely viscous cements,y or' the very 16 undesirable phase separation. ~ .
17 It is therefore desirable to provide a dispersion 18 polymerization process in which there is no need to store the 19 dispersing agent prior to the commencement of the dispersion polymerization process.
21 It is an object of the present invention..to provide a 22 polymerization process employing an anionic ini.tiatiori system to 23 promote the random polymerization of styrene and butadiene monomers 24 in a nonaqueous dispersion into SBR having 35 to 70% by weight of styrene in the presence of a dispersing agent that is prepared in 26 situ, that is, during the polymerization reaction.
.. ~ 211~~~~
1 Such a nonaqueous dispersion polymerization process offers 2 many advantages including improved stable dispersions, improved 3. heat transfer, energy savings, high polymer concentrations in the 4 reaction medium, increased production capacity, and the production of very high molecular weight polymers; and no need to store the 6 dispersing agent prior-to its use.
8 In accordance with the present invention, a process is 9 provided for the preparation of a random, copolymer by the nonaqueous~dispersion random polymerization of a mixture of 30 to 11 65% by weight of a conjugated diolefin monomer, preferably 12 butadiene,-and 35 to 70% by weight of a vinyl substituted aromatic 13 monomer, preferably styrene, in a liquid aliphatic hydrocarbon 14 dispersion medium with an anionic initiator catalyst system in the presence of a block copolymeric dispersing~~agent which is prepared 16 in situ. At least one block of the dispersing agent is prepared 17 prior to the dispersion polymerization reaction and at least one 18 block of the dispersing agent is prepared in situ during the 19 dispersion copolymerization. The bloclc,that is prepared in situ has the polymer structure of the random copolymer.
22 The copolymer rubbers. prepared by the process of the instant 23 invention are random copolymers formed by the copolymerization of 24 a conjugated diene monomer and a vinyl substituted aromatic ~1~.~'~~3 1 monomer. A random copolymer is defined as a copolymer of a diene 2 monomer and a vinyl aromatic monomer (VAM) in which no more than 5%
3 by weight of the copolymer is composed of VAM blocks of 10 or more 4 VAM units. Preferably, no more than 5% by weight of the VAM is contained in blocks of 10 or more VAM units. Most preferably, 100%
6 of VAM units are in blocks of less than 10 VAM units and 80% of VAM
7 units are in blocks of less than 5 VAM units. This definition 8 applies to polymers having .less than 50% by weight of styrene 9 content. Somewhat higher levels of VAM blocks can be tolerated at 50-70% styrene levels in SBR. ~ ~ ~.
11 . The conjugated diene monomers utilized in the synthesis of 12 such copolymer rubbers generally contain from 4 to 12 carbon atoms.
13 Diene monomers containing from 4 to 8 carbon atoms are generally 14 preferred for commercial purposes. For similar reasons, 1,3-butadiene and isoprene are tl~e most commonly utilized conjugated 16 diolefin monomers. Some additibnal conjugated diolefin monomers 17 that can be utilized include 2,3-dimethyl-1,3-butadiene, 18 piperylene, 3-butyl-1,3-octadiene, 2-phenyl-1,3-butadiene, and the 19 like, alone or in admixture.
Vinyl substituted aromatic, monomers, also referred to as vinyl 21 aromatic monomers suitable for use in preparing the random 22 copolymers of this invention include any vinyl or alphamethyl vinyl 23 aromatic compounds capable of being polymerized by an anionic 24 initiator. Particularly useful monomers for this purpose are vinyl aryl and alphamethyl-vinyl aryl compounds such as styrene, 26 alphamethyl styrene, vinyl toluene, vinyl naphthalene, z~~H~~
1 alphamethylvinyl toluene, vinyl diphenyl, and corresponding 2 compounds in which the aromatic nucleus may have other alkyl 3 derivatives up to a total of 8 carbon atoms. Certain vinyl 4 substituted aromatic monomers are not suitable for use in this dispersion polymerization process because homopolymers of these 6 -. monomers are soluble in linear alkane solvents such as hexane and 7 their copolymers with dime are also soluble. A specific example 8 of an unsuitable monomer type is t-butyl styrene.
FIELD OF THE INVENTION
1 . The present invention relates to an anionic styrene-butadiene 2 type rubber polymerization process conducted in a nonaqueous 3 dispersion utilizing butadiene-type and styrene-type monomers and 4 a dispersing agent formed in situ during polymerization.
BACKGROUND OF THE INVENTION
6 In many prior art nonaqueous dispersion polymerization 7 systems, organic dispersing medium have been utilized having poor '8 solvent properties for the polymer being produced. A dispersing 9 agent was therefore utilized in the organic medium in order to' disperse the polymer being formed throughout the medium. These 11 dispersing agents or dispersants were generally polymeric materials 12 such as block copolymers, random copolymers, or homopolymers as 13 described in U.S. Patent Nos. 4,098,980 and 4,452,960. .
14 Styrene-butadiene rubbers (SBR) have generally been prepared in solvents in which~SBR is soluble. However; only SBR's having a 16 styrene content of less than 35% are soluble in hexane or other 17 non-cyclic aliphatic solvents. These higher styrene content SBR
18 .polymers are not completely insoluble in the aliphatic solvents, 19 and, in fact, are highly swollen in these solvents. However, SBR's._.
having a styrene content greater than 35% necessarily'have been 21 polymerized in aromatic or cycloaliphatic solvents via solution 22 polymerization.
23 The applicant first determined that certain pre-made 24 dispersing -agents can be utilized to conduct the nonaqueous 2~~.~fjsJ~
1 dispersion polymerization production of SBR having a styrene 2 content greater than 35% by weight in aliphatic dispersing medium 3 such ~as.hexane. Although the dispersion process using a pre-made 4 dispersant works well, it has one~shortcoming from a practical or commercial scale up point of view. The dispersant must be prepared 6 separately and stored for subsequent use in the polymerization 7 process. Storage tank and transfer lines require a large capital 8 expenditure and the synthesis of the dispersant and transfer time 9 into the polymerization reactor results in higher production costs.
In these first dispersion SBR studies, a single d~iblock 11 polymer consisting of a short block (5%-10% of total polymer) of 12 hexane soluble polybutadiene and a long block (90%-95% of total) of 13 high styrene content SBR was prepared in the absence of a 14 dispersing agent. Synthesis of this polymer structure in hexane resulted in either extremely viscous cements,y or' the very 16 undesirable phase separation. ~ .
17 It is therefore desirable to provide a dispersion 18 polymerization process in which there is no need to store the 19 dispersing agent prior to the commencement of the dispersion polymerization process.
21 It is an object of the present invention..to provide a 22 polymerization process employing an anionic ini.tiatiori system to 23 promote the random polymerization of styrene and butadiene monomers 24 in a nonaqueous dispersion into SBR having 35 to 70% by weight of styrene in the presence of a dispersing agent that is prepared in 26 situ, that is, during the polymerization reaction.
.. ~ 211~~~~
1 Such a nonaqueous dispersion polymerization process offers 2 many advantages including improved stable dispersions, improved 3. heat transfer, energy savings, high polymer concentrations in the 4 reaction medium, increased production capacity, and the production of very high molecular weight polymers; and no need to store the 6 dispersing agent prior-to its use.
8 In accordance with the present invention, a process is 9 provided for the preparation of a random, copolymer by the nonaqueous~dispersion random polymerization of a mixture of 30 to 11 65% by weight of a conjugated diolefin monomer, preferably 12 butadiene,-and 35 to 70% by weight of a vinyl substituted aromatic 13 monomer, preferably styrene, in a liquid aliphatic hydrocarbon 14 dispersion medium with an anionic initiator catalyst system in the presence of a block copolymeric dispersing~~agent which is prepared 16 in situ. At least one block of the dispersing agent is prepared 17 prior to the dispersion polymerization reaction and at least one 18 block of the dispersing agent is prepared in situ during the 19 dispersion copolymerization. The bloclc,that is prepared in situ has the polymer structure of the random copolymer.
22 The copolymer rubbers. prepared by the process of the instant 23 invention are random copolymers formed by the copolymerization of 24 a conjugated diene monomer and a vinyl substituted aromatic ~1~.~'~~3 1 monomer. A random copolymer is defined as a copolymer of a diene 2 monomer and a vinyl aromatic monomer (VAM) in which no more than 5%
3 by weight of the copolymer is composed of VAM blocks of 10 or more 4 VAM units. Preferably, no more than 5% by weight of the VAM is contained in blocks of 10 or more VAM units. Most preferably, 100%
6 of VAM units are in blocks of less than 10 VAM units and 80% of VAM
7 units are in blocks of less than 5 VAM units. This definition 8 applies to polymers having .less than 50% by weight of styrene 9 content. Somewhat higher levels of VAM blocks can be tolerated at 50-70% styrene levels in SBR. ~ ~ ~.
11 . The conjugated diene monomers utilized in the synthesis of 12 such copolymer rubbers generally contain from 4 to 12 carbon atoms.
13 Diene monomers containing from 4 to 8 carbon atoms are generally 14 preferred for commercial purposes. For similar reasons, 1,3-butadiene and isoprene are tl~e most commonly utilized conjugated 16 diolefin monomers. Some additibnal conjugated diolefin monomers 17 that can be utilized include 2,3-dimethyl-1,3-butadiene, 18 piperylene, 3-butyl-1,3-octadiene, 2-phenyl-1,3-butadiene, and the 19 like, alone or in admixture.
Vinyl substituted aromatic, monomers, also referred to as vinyl 21 aromatic monomers suitable for use in preparing the random 22 copolymers of this invention include any vinyl or alphamethyl vinyl 23 aromatic compounds capable of being polymerized by an anionic 24 initiator. Particularly useful monomers for this purpose are vinyl aryl and alphamethyl-vinyl aryl compounds such as styrene, 26 alphamethyl styrene, vinyl toluene, vinyl naphthalene, z~~H~~
1 alphamethylvinyl toluene, vinyl diphenyl, and corresponding 2 compounds in which the aromatic nucleus may have other alkyl 3 derivatives up to a total of 8 carbon atoms. Certain vinyl 4 substituted aromatic monomers are not suitable for use in this dispersion polymerization process because homopolymers of these 6 -. monomers are soluble in linear alkane solvents such as hexane and 7 their copolymers with dime are also soluble. A specific example 8 of an unsuitable monomer type is t-butyl styrene.
9 The preferred comonomers for use in the process,. of the present invention are styrene and butadiene for production of a SBR
11 product. In the production of the random copolymers of the present 12 invention, the vinyl 'substituted aromatic monomer contributed 13 content ranges from 35 to 70% by weight, preferably 40 to 60% by 14 weight, and the d'iene monomer contributed content ranges from 30 to 65% by weight, preferably 40 to 60% by weight.
16 The copolymers 'produced by the process of the present 17 invention can be prepared from any combination of each of the 18 aforementioned conjugated diene and vinyl aromatic monomers. While 19 the following discussion relates to the production of randomized styrene-butadiene ,rubbers (SBR) from styrene and butadiene 21 monomers, it is apparent,that this discussion encompasses the use 22 of any combinat-ion of~ the above-identified vinyl-substituted 23 aromatic hydrocarbons and conjugated dienes. The SBR-type 24 copolymers prepared by the process of the present invention have a number average molecular weight of 20,000-2,500,000 preferably 26 75,000-500,000 as determined by 6e1 Permeation Chromatography 1 (GPC). In addition to the ability to make high molecular weight 2 polymers possessing good hot tensile strength, these copolymers 3 have good oil acceptance or extendibility, modulus, tensile 4 strength and stability against heat and aging. These copolymers are especially useful in the production of high performance tires.
6 The solvents, also known as the dispersing medium, used in the 7 present polymerization process may consist of up to 100% of non-8 cyclic or linear aliphatic hydrocarbons, preferably up to 70% of 9 non-cyclic or linear aliphatic hydrocarbons, up to 30% by weight of the total solvent can be provided by at least one alicyclic 11 hydrocarbon such as cyclopentane, methylcyclopentane, cyclohexane, 12 methylcyclohexane and aromatic hydrocarbons such as benzene and 13 toluene. Examples of solvents that may be used in the present 14 polymerization process are aliphatic hydrocarbons, preferably linear aliphatic hydrocarbons, including butane, pentane, hexane, 16 heptane, isopentane, octane, isooctane, nonane, and the like and 17 mixtures thereof. Solvents are employed within such a range as 18 being necessary to maintain a dispersion state in said solvent and 19 for properly controlling stability of a polymer dispersion. The insolubility of SBR in a solvent is a function of molecular weight 21 of the polymer, temperature, and the solubility parameter, which is 22 the square root of the cohesive energy density, that is;
23 solubility parameter (s.p.) - l~DEjV
24 wherein E is internal energy and V is the molar volume. For polymers, it is often best to calculate s.p. as displayed in the 26 article "A Method for Estimating the Solubility Parameters and 27 Molar Volumes of Liquids" in Polymer Engineering & Science, vol.
28 14, no. 2, pp 147-154 (1974). The calculated s.p. is 8.6 for 29 polybutadiene, 9.2 for SBR having a 35% styrene content, and 10.5 1 for polystyrene. The s.p, of n-hexane is 7.3 and a 35% styrene SBR
2 has only partial solubility in n-hexane. The solubility parameter 3 (s. p.) of SBR or other random copolymers produced by the present 4 invention must be at least 1.9 greater than the s.p. of the solvent or dispersing medium, so that the SBR is not completely soluble in 6 the dispersing medium and can thus form an acceptable dispersion.
7 The aliphatic hydrocarbon is used as the liquid medium to disperse 8 the mixture of copolymers into fine particles.
9 The preferred solvent for use as a dispersing medium in the present process n-hexane. While the solvent may consist of up to 11 100% of non-cyclic or linear aliphatic hydrocarbons, preferably up 12 to 70~ of non-cyclic or linear.aliphatic hydrocarbons, up to 30% by 13 weight -of the total solvent can be provided by at least one 14 alicyclic hydrocarbon such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane and aromatic hydrocarbons such as 16 benzene and toluene. A higher percentage of VAM units in the SBR
17 allows for a higher percentage of non-aliphatic linear hydrocarbons 18 to be present in a solvent mixture. However, for a SBR with 19 approximately 38 to 42% styrene content, no more than 15% of the solvent should consist of an alicyclic hydrocarbon or admixture 21 such as cyclohexane or methyl cyclopentane, for example. The random 22 copolymer product contains l0 to 50 weight percent solids relative 23 to the liquid hydrocarbon dispersing medium to yield a fluid 24 polymer dispersion which can be easily handled.
The copolymerization process of the present invention is 26 performed in a non-aqueous dispersing medium in the presence of an 27 anionic initiator catalyst system and a block copolymer dispersing 28 agent that is prepared in situ during the copolymerization process.
29 The block copolymer dispersing agents useful in the present 2~.~.~~~~
1 invention are polyblock copolymers, in that they are selected from 2 a variety of polymers containing at least two blocks linked by 3 chemical valences wherein at least one of said blocks ("A" block) 4 is soluble in the dispersion medium and at least another of said blocks ("B" block) is insoluble in the dispersion medium. The 6 dispersing agent acts to disperse copolymers hereinafter identified:
7 as ' C' copolymers, formed from conjugated dienes and vinyl aromatic 8 monomers which are formed in the presence of the dispersing agent.
9 The insoluble "B" block provides an anchor segment for attachment ~ to the 'C' copolymer, i.e.,the SBR polymer. The soluble "A" block 11 of the dispersing agent provides a sheath around the otherwise 12 insoluble copolymer and maintains the copolymeric product as 13 numerous small discrete particles rather.than an agglomerated or 14 highly coalesced mass.
The soluble "A" block of the dispersing agent comprises about 16 1 to about 15 percent by weight of the total dispersion copolymer I'~; 17 including the dispersing agent and the 'C' copolymer, i.e., the 18 SBR-type random copolymer. The insoluble "B" block of the 19 dispersing agent is prepared in situ during the polymerization of the SBR-type random copolymer, therefore the "B" block has the same 21 composition as the 'C' copolymers, namely the SBR-type random 22 copolymer formed during the dispersion copolymerization process.
23 The total dispersion copolymer composition preferably contains 24 about 2 to about 10 percent by weight of the soluble "A" block and i about 90 to about 98 percent by weight of the insoluble "B" block .
26 and 'C' copolymers most preferably from 4 to 8 weight percent of 1 "A" and 92 to about 96 percent by weight of "B" block and ' C' 2 copolymers being most preferred. The number average molecular 3 weight M" of each '!A" block is preferably at least 500 and a 4 maximum of 200,000, most preferably 1,000 to 100,000.
The number average molecular weights of each "B" block is the 6 same as the 'C' copolymers or SBR-type random polymer, namely at 7 least 20,000 and a maximum of 2,500,000, preferably 75,000 to 8, 500,000.
9,- While it is believed that the soluble "A" can be prepared from 10~~' any monomer providing a soluble block in the dispersing medium 11 subject to known anionic polymerization constraints, it is 12 preferred that the soluble "A" block be selected from a polymer 13 formed by polymerization of conjugated diene monomers or be 14 selected from a copolymer formed by copolymerization of conjugated diene monomers and vinyl substituted aromatic monomers. The 16 soluble "A" block is most preferably selected from a polymer or' a 17 copolymer formed from 75 to 100 parts by weight, preferably .75 to 18 98 parts, of conjugated diene monomer contributed units and 0 to 25 19 parts by weight, preferably 2 to 25 parts, of vinyl substituted aromatic monomer contributed units with the polymer or copolymer 21 blocks being soluble in the hydrocarbon dispersion medium.
22 The insoluble "B" block is produced in the dispersion .
23 polymerization process during the formation of the random copolymer 24 having the same composition as the random copolymer. The insoluble "B" block is anchored to the surface of or the outer layer of the 26 copolymer particle by physical adsorption processes, as for 211~~J3 1 example, by van der Waals forces. Therefore, its main criteria for 2 success as an anchor is to be relatively immiscible in the 3 dispersing -medium. The "B" block can be prepared by the 4 copolymerization of 30 to 65 parts by weight of conjugated diene monomer contributed units and 35 to 70 parts by weight of vinyl 6 substituted aromatic monomer contributed units.
7 The preferred dispersing agents, prepared in situ for use in 8 the present process can be represented by the following structural 9 formula:
( B ~ ~s-ioox~so: asx ) - ( B ~ 30-6sx/ S35-70X ) 11 wherein B' represents butadiene monomer units and S represents 12- styrene monomer units, all blocks of (B'/S) are randomized 13 copolymers of butadiene and styrene monomers. The subscripts 14 display the possible percentage by weight of each monomer in the blocks. Most preferred. diene/vinyl aromatic block .copolymers 16 having (1) a,~first block "A" formed from polybutadiene or~ by the 17 random copolymerization of styrene/butadiene to form an SBR block 18 having less than 25% by weight of styrene contributed content, and 19 (2) a second block "B" formed from a randomized copolymer of styrene/butadiene having a styrene contributed content comparable 21 with the SBR copolymer to be made by the process of. the present 22 invention, namely in the range from 35% to 70% by weight of styrene 23 and 30% to 65% by. weight of butadiene.
24 Diblock A-B dispersing agents are typically prepared utilizing monolithium anionic initiators. The use of dilithium anionic 26 initiators promotes the production of. triblock B-A-B dispersing 1 agents. The dispersing agents prepared in situ and used in the 2 preparation of the SBR copolymers are recovered as a blend with the 3 '.C' copolymers, i.e. SBR copolymers. The dispersing agents are 4 prepared and present in aw amount ranging from about 2 to 50%, preferably 5-35%, and most preferably 10-25% by weight of the total 6 weight of the dispersion copolymer which includes the dispersing 7 agent and the subsequently formed 'C' copolymer, i.e. SBR
8 copolymer.
9 The catalyst systems are anionic initiators for use in preparing the SBR copolymers and the dispersing agent, preferably y 11 any organolith'ium catalyst which is known in the art as being 12 useful in the polymerization of vinyl aromatic hydrocarbons and 13 conjugated dienes. Suitable catalysts which initiate 14 polymerization of the monomer system and dispersing agent include organolithium catalysts which have the formula R(Li)x wherein R
16 represents a hydrocarbyl radical of 1 to 20, preferably 2-8, carbon 17 atoms per R group, and x is an integer of 1-4, preferably 1 or 2.
18 Typical R groups include aliphatic radicals and cycloaliphatic 19 radicals, such as alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, aryl and alkylaryl radicals...
21 Specific examples of R groups for subst.~tution in the above 22 formula include primary, secondary and tertiazy~ groups such as 23 methyl., ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-24 amyl, isoamyl, n-hexyl n-octyl, n-decyl, cyclopentyl-methyl, eyclohexyl-ethyl, cyclopentylethyl, methyl-cyclopentylethyl, 26 cyclopentyl, cyclohexyl, 2,2,1-bicycloheptyl, methylcyclopentyl, ~i~?(~~J
1 dimethylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, 2 dimethylcyclohexyl, ethylcyclohexyl, iso-propylcyclohexyl, and the 3 like.
4 Specific examples of other suitable lithium catalysts include:
phenyllithium, naphthyllithium, 4-butylphenyllithium, p-6 tolyllithium, 4-phenylbutyllithium: 4-butyl-cyclohexyllithium, 4-7 cyclohexylbutyllithium, 1,4-dilithiobutane, 1,10-dilithio-decane, 8 1,20-dilithioeicosane, 1,4-dilithiobenzene, 1,4-, 9 dilithionaphthalene, 1,10-dilithioanthracene, 1,2-dilithio-1y2~-.
diphenylethane, 1,3,5-trilithiopentane,.1,5,15-trilithioeicoxane~;;~1 11 1,3,5-trilithiocyclohexane, 1,3,5,8-tetralithiodecane, 1,5,10,20-12 tetralithioeicosane, 1,2,4,6-tetralithiocyclohexane, 4,4'-13 dilithiobiphenyl, and the like.
14 Mixtures of different lithium catalysts can also be employed, preferably containing one or more;lithium compounds such as R(Li)x.
16 The preferred lithium catalyst for use in the present invention is ~17 n-butyllithium.
18 Other lithium catalysts which can be employed are lithium 19 dialkyl amines, lithium dialkyl pho~sphines, lithium alkyl aryl phosphines, lithium diaryl phosphines and trialkyl tin lithium such 21 as tributyl-tin-lithium:
22 Anionic initiators are typically. employed in amounts ranging 23 from 0.2 millimoles to 100 millimoles of anionic initiator per 24 hundred grams of monomer in the reaction vessel.
I 25 All amounts of anionic initiator are indicated by hundred L
26 grams of monomer or by ratio of components in the instant invention ~1~~'~~3 1 and are considered to be catalytically effective amounts, that is, 2 effective amounts for initiating and conducting polymerization of 3 the dispersing agent and the disclosed monomer systems to produce 4 copolymers of the present invention.
It is preferred to utilize 10 to 50~ by weight of the anionic 6 initiator to prepare the initial "A" block of the dispersing agent.
7 The remaining portion of the initiator is then added during the 8 charging of the monomers to simultaneously produce the "B" block of 9 the dispersing agent and the copolymer from vinyl aromatic monomers ~',10 and conjugated diene monomers..
i11 A SBR copolymer randomizing agent such as an ether or an amine I12 is preferably added to the SBR dispersion polymerization system. as ~13 part of the catalyst system in an amount effective to promote f 14 random copolymerization of the styrene and butadiene monomers.
Other suitable randomizing agents are well known in the art such as 16 sodium or potassium alkoxides~. Randomizing agents are employed in ' 17 the polymerization system in amounts generally ranging from a molar 18 ratio of 1:100 to 1:1 of randomizing agent to anionic initiator.
19 Modifying agents such as ethers, tertiary amines, chelating ethers or amines, and sodium or potassium alkoxides or alkyls, may 21 be added to increase~the.l,2-addition reaction of the diene monomer 22 in the SBR. Such modifying~-agents are well known in the art, such 23 as tetrahydrofuran, tetramethylethylene diamine, d~ethylether and 24 the like, and these modifying agents may be employed in amounts generally ranging from 1:10 to 100:1 molar ratio of the modifier to 26 anionic initiator. The 1,2-addition product can be increased from ~~~~.3~~J .
1 the 5-15% range to as high as 90-100% of the diene monomer units 2 being incorporated into the "A" or "B" block of the dispersing 3 agent and the 'C' copolymer.
4 The preferred 1,2-vinyl content of the "B" block and the 'C' copolymer, i.e. SBR produced in accordance with the process of the 6 instant invention, ranges between 10 to 65% of the diene monomer 7 contributed units. The 1,2-vinyl content in the diene contributed 8 units of the "B" block of the dispersing agent is thus identical to 9 the desired final 1,2-vinyl content of~the.'C' copolymer being produced herein.
11 The reaction mixture utilized in the nonaqueous dispersion 12 polymerization of butadiene and styrene to produce a random 13 copolymer having a styrene content between 35 and 70 percent is 14 comprised.of a liquid nonaqueous dispersion medium, the living "A"
block of a dispersing agent, 30 to 65 parts by weight of butadiene 16 monomer ands 35~ to 70 parts by weight of styrene monomer, and 17 catalyst system. Such a polymerization can be run over a 18 temperature range from 0° up to 150°C. Most generally, it is 19 preferred to utilize a reaction temperature from 40°C. to 110°C.
The reaction, time required in such a polymerization will vary with 21 the reaction.temperature, monomer concentration, catalyst system, 22 and cathlyst level. Generally, this reaction time will vary from 23 about 20 minutes up to about 30 hours. Commonly, it will be 24 preferred to utilize a reaction time from about 1 up to about 6 hours.
21~.~0~~
1 The amount of butadiene and styrene monomers that can be 2 utilized in such a nonaqiieous dispersion polymerization reaction 3 mixture can be varied from about 10 to about 50 weight percent by 4 weight based upon the total reactionmixture. It preferred is to have a final polymer concentration 35 percent ranging from 20 to by 6 weight based upon the total reactionmixture.
7 It is desirable to conduct this polymerizationin an oxygen 8 and moisture free environment. For example, it desirable is to 9 sparge the reaction vessel with dxy nitrogen (or other inert gas) and to run the polymerization under a dry nitrogen atmosphere. The 11 pressure in the reaction system during the polymerization generally 12 will be a function of the inert gas, concentration, polymerization 13 temperature, the monomer concentration; and the vapor pressure of 14 .nonaqueous dispersion medium. The polymerization pressure will usually be maintained within the range between 1.0 and 15 16 atmospheres.
17 The nonaqueous dispersion polymerization can be run in a batch 18 process by simply adding the initiator components to a nonaqueous 19 dispersion medium containing butadiene and styrene monomers and the "A" block of a polymeric dispersing agent to form the reaction 21 .mixture. In a semi-batch process, the monomers are metered into 22 '~ the reactor containing the dispersion medium and an anionic 23 initiator. The "A" block of the dispersing agent can either.be 24 metered into the reactor with the monomers or added to the reactor before the monomers are added or is preferably premade in the 26 reactor as in the following examples. During the course of the ~1~~~~
1 polymerization it will generally be desirable to provide some form 2 of agitation to the reaction mixture, such as stirring, shaking, or 3 tumbling. A short stopping agent such as .an alcohol may be 4 employed to terminate the polymerization after the desired reaction time or at the desired percent conversion of monomers to copolymer.
6 In general, the conversion of monomers inta polymers is allowed to 7 proceed to about completion. An appropriate antioxidant can be 8 added at this stage of the process.
9 The nonaqueous dispersions formed in this polymerization process have a solids concentration ranging between about l0 to 50 11 weight percent and are quite fluid. This fluidity permits greatly 12 improved heat transfer as compared to the fluidity of.solutions of 13 SBR copolymers prepared using solution polymerization techniques.
14 Due to the relative fluidity of these nonaqueous dispersions, both a higher molecular weight polymer can be produced and the r16 concentration of dispersed SBR copolymers in the medium can be 17 increased by 25 to 100% or more over the maximum allowable 18 concentrations in solution polymerization techniques.
19 The elastomeric SBR copolymer can be recovered from the hydrocarbon solvent by steam desolventization or by drum drying 21, techniques thus providing energy savings due to higher solids 22 levels. By proper control of particle size, the polymers can be .23 recovered by filtration or centrifugation techniques.
24 The recovered copolymer products, depending on their molecular weights and compositions, can be used for a variety of goods such 26 as tires and various rubber molded products.
1 It is believed that one skilled in the art can, using the 2 preceding description, utilize the present invention to its fullest 3 extent. The following preferred. specific embodiments are, 4 therefore, to be construed as merely illustrative of the catalyst system and the polymerization process of the present invention.
6 All percentages identified in the examples are by weight: unless-? otherwise indicated.
8 EXAMPLES 1 and 2 i 9 ~ Preparation of "A" Block of Dispersing Agent A one gallon reactor was charged with 30 g. of 10 % styrene/90%
11 butadiene in 500 ml of hexane, 0.8 mmole of n-butyllithium and 3.2 12 mmoles of tetrahydrofuran (THF). The reactor was heated to and f 13 maintained at 95~C. for ten minutes, after which time 5.mmoles of 14 isopropanol were added to terminate the.reaction to provide the "A"
block of a dispersing agent. This procedure was repeated a second 16 time and the properties of the first and second recovered "A"
17 blocks are as follows as~shown in Examples 1 and 2.
3 EXAMPLE NO. 1 2 4 Yield % 68.7 80.0 Mn (GPC) 80,400 57,000 6 MW~Mn 1.38 1.45 7 Vinyl % 18.9 18.9 8 Styrene % 7.2 7.7 9 Tg (DSC) C. -84 -82 12In si tu dispersion polymerization reactions were conducted 13utilizing reactants and in accordance ith conditions identified w 14in Tables II and III in Examples 3 to 12. The "A" blocks of 15dispersing agents used in each example were prepared in hexane 16following the same procedure of Example 1 utilizing the reactants 17and conditions in Tables II and III, displayed under Step 18however th e blocks were not terminated. Examples 3 to 7 employed 19n-butyllithium examples 8 to 12 employed as the RLi initiator and 20tributyl-SnLi as the RLi initiator in the amounts indicated.
The 21modifiers utilized in these examples included tetrahydrofuran 22(THF), bis oxolanyl propane (OOPS) and tetramethylethylene diamine 23(TMEDA) in amounts identified as modifiermillimoles (MOD mmol).
1 After formation of the first living "A" block copolymer in 2 each example, the living "A" block copolymer in solution as 3 prepared in Step 1 and a subsequent charge identified under Step 2 4 in Tables II and III of 1,3-butadiene (1,3-BD) in 24.90 hexane solution and styrene in 33% hexane solution were blended along 6 with additional anionic initiator (RLi) in the reactor either in a 7 batch or semibatch (SEMI) reaction (RXN TYPE). Each reaction 8 proceeded at the indicated time and temperature. Polymerizations 9 were terminated in Examples 3 to 7 by the addition of isopropanol and were terminated in Examples 8 to 12 by the addition of 11 dibutyl-SnCl2. These polymerization processes yielded an A-B
12 diblock copolymer dispersing agent which was formed in situ with a 13 random copolymer (identified in Tables II and III as 'C' polymer).
14 The composition of the 'C' polymer and the "B" block were equivalent. Good dispersions were formed in all examples at both 16 the reaction temperature (hot) and at room temperature (cold).
17 Product properties of the recovered blends of A-B diblock 18 dispersing agent and random copolymer are displayed under product 19 properties on Tables II and III. The solids levels of the resultant dispersions produced in Examples 3 to 12 ranged between 21 21 to 25 percent.
N ~ ~ tJ~
TABLE II
IN SITU DISPERSION SBR USING n-BuLi 1 Example No. 3 4 5 6 7 4 'A' BLOCK PREPARATION
1,3-BD (g) 24 27 13.5 13.5 27 6 STYRENE (g) 3 3 1.5 1.5 3 7 RLi (mmol) 0.7 1:-0 1.0 1.0 1.0 9 MOD. (mmol) 8.0 4.0 0.5 0.3 0.4 TEMP. (F.) 150 200 200 200 200 11 TIME (min.) 60 10 10 10 10 'B' BLOCK & POLY, ~PARATION
' C' E~
16 1,3-BD (g) 266 250 155 155 226' 17 STYRENE (g) 199 204 303 303 228 18 RLi (mmol) 3.0 3.0 4.2 2.2 3.0 19 MOD. (mmol) ___ ___ ___ ___ ___ RXN TYPE SEMI BATCH SEMI SEMI SEMI
21 TIME (min.) 80 150 70 80 95 22 TEMP. (F.) 200 277 200 200 200 ~
23 max '~ PRODUCT PROPERTIES
27 Ts ~('C. ) -47 -18 +5 -4 -34 %VINYL 17.2 47.2 39.5 35.0 20.5 31 (BD=100) 32 %STYRENE 36.8 45.6 67.7 67.3 51.1 33 %BLOCK ~ 4.4 26.1 45.9 42.4 27.3 34 (STY=100) 37 M"/10-3 205 158 127.2 177.3 165.1 38 M"/M" 1.32 1.25 1.6 1.59 1.44 PHYSICAL STATE OF DISPERSION
41 .
43 VISC. VISC. VISC. VISC. VISC.
COLD LOW LOW LOW LOW LOW
46 VISC. VISC. VISC. VISC. VISC.
~1~2~;~s TABLE III
IN SITU DISPERSION SBR USING BU3SnLi . Example No. 8 9 10 11 12 4 'A' BLOCK PREPARATION
1,3-BD (g) 24 36 27 27 27 6 STYRENE (g) 3 4 3 3 3 7 RLi (mmol) 0:7 0.8 0.8 0.8 0.8 9 MOD. (mmol) 3.5 1.6 3.2 3.2 3.2 TEMP. (F.) 150 195 200 200 200 11 TIME (min.) 45 10 10 10 10 'B' BLOCK & POLYMER PREPARATION
' C' ~
~
16 1,3-BD (g 266 . 276 267. 271 280 ) 17 STYRENE (g) 199 184 193 189 180 18 RLi (mmol) 4.1 4.2 4.2 4.2 4.2, 19 MOD. (mmol) 20.5 8.4 8.4 8.4 8.4~
RXN TYPE SEMI SEMI SEMI SEMI SEMI
21 TIME (min.) 75 67 90 90 85 22 TEMP. 'F. 190 ~ 200 200 200 200 26 Tg ('C.) -34 -47 -39 -39 -43 ~
29 %VINYL 23.2 17.6 18.7 18.9 19.2 (BD=100) 31 %STYRENE 40.0 36.4 39.5 38.6 37.3 32 %BLOCK 3.8 6.4 8.9 9.6 9.1 33 (STY=100) GPC
36 M"/10-3 196.2 180.4 ~ 65.7 160. 8 154.1 ', M"/M" 1.49 1.52 ~ 1..54 1.51 1.55 139 PHYSICAL STATEOF DISPERSION .
- ~
~~~
!41 ~ HOT MEDIUM MEDIUM LOW LOW MEDIUM
'~,42 VISC. VISC. VISC. VISC. VISC.
~~
',44COLD IAW MEDIUM LOW LOW LOW
145 VISC. VISC. VISC. VISC. VISC.
~~l~~~J
1 While certain representative embodiments and details have been 2 shown for the purpose of illustrating the invention, it will be 3 apparent to those skilled in the art that various changes and 4 modifications may be made therein without departing from the scope of the invention.
11 product. In the production of the random copolymers of the present 12 invention, the vinyl 'substituted aromatic monomer contributed 13 content ranges from 35 to 70% by weight, preferably 40 to 60% by 14 weight, and the d'iene monomer contributed content ranges from 30 to 65% by weight, preferably 40 to 60% by weight.
16 The copolymers 'produced by the process of the present 17 invention can be prepared from any combination of each of the 18 aforementioned conjugated diene and vinyl aromatic monomers. While 19 the following discussion relates to the production of randomized styrene-butadiene ,rubbers (SBR) from styrene and butadiene 21 monomers, it is apparent,that this discussion encompasses the use 22 of any combinat-ion of~ the above-identified vinyl-substituted 23 aromatic hydrocarbons and conjugated dienes. The SBR-type 24 copolymers prepared by the process of the present invention have a number average molecular weight of 20,000-2,500,000 preferably 26 75,000-500,000 as determined by 6e1 Permeation Chromatography 1 (GPC). In addition to the ability to make high molecular weight 2 polymers possessing good hot tensile strength, these copolymers 3 have good oil acceptance or extendibility, modulus, tensile 4 strength and stability against heat and aging. These copolymers are especially useful in the production of high performance tires.
6 The solvents, also known as the dispersing medium, used in the 7 present polymerization process may consist of up to 100% of non-8 cyclic or linear aliphatic hydrocarbons, preferably up to 70% of 9 non-cyclic or linear aliphatic hydrocarbons, up to 30% by weight of the total solvent can be provided by at least one alicyclic 11 hydrocarbon such as cyclopentane, methylcyclopentane, cyclohexane, 12 methylcyclohexane and aromatic hydrocarbons such as benzene and 13 toluene. Examples of solvents that may be used in the present 14 polymerization process are aliphatic hydrocarbons, preferably linear aliphatic hydrocarbons, including butane, pentane, hexane, 16 heptane, isopentane, octane, isooctane, nonane, and the like and 17 mixtures thereof. Solvents are employed within such a range as 18 being necessary to maintain a dispersion state in said solvent and 19 for properly controlling stability of a polymer dispersion. The insolubility of SBR in a solvent is a function of molecular weight 21 of the polymer, temperature, and the solubility parameter, which is 22 the square root of the cohesive energy density, that is;
23 solubility parameter (s.p.) - l~DEjV
24 wherein E is internal energy and V is the molar volume. For polymers, it is often best to calculate s.p. as displayed in the 26 article "A Method for Estimating the Solubility Parameters and 27 Molar Volumes of Liquids" in Polymer Engineering & Science, vol.
28 14, no. 2, pp 147-154 (1974). The calculated s.p. is 8.6 for 29 polybutadiene, 9.2 for SBR having a 35% styrene content, and 10.5 1 for polystyrene. The s.p, of n-hexane is 7.3 and a 35% styrene SBR
2 has only partial solubility in n-hexane. The solubility parameter 3 (s. p.) of SBR or other random copolymers produced by the present 4 invention must be at least 1.9 greater than the s.p. of the solvent or dispersing medium, so that the SBR is not completely soluble in 6 the dispersing medium and can thus form an acceptable dispersion.
7 The aliphatic hydrocarbon is used as the liquid medium to disperse 8 the mixture of copolymers into fine particles.
9 The preferred solvent for use as a dispersing medium in the present process n-hexane. While the solvent may consist of up to 11 100% of non-cyclic or linear aliphatic hydrocarbons, preferably up 12 to 70~ of non-cyclic or linear.aliphatic hydrocarbons, up to 30% by 13 weight -of the total solvent can be provided by at least one 14 alicyclic hydrocarbon such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane and aromatic hydrocarbons such as 16 benzene and toluene. A higher percentage of VAM units in the SBR
17 allows for a higher percentage of non-aliphatic linear hydrocarbons 18 to be present in a solvent mixture. However, for a SBR with 19 approximately 38 to 42% styrene content, no more than 15% of the solvent should consist of an alicyclic hydrocarbon or admixture 21 such as cyclohexane or methyl cyclopentane, for example. The random 22 copolymer product contains l0 to 50 weight percent solids relative 23 to the liquid hydrocarbon dispersing medium to yield a fluid 24 polymer dispersion which can be easily handled.
The copolymerization process of the present invention is 26 performed in a non-aqueous dispersing medium in the presence of an 27 anionic initiator catalyst system and a block copolymer dispersing 28 agent that is prepared in situ during the copolymerization process.
29 The block copolymer dispersing agents useful in the present 2~.~.~~~~
1 invention are polyblock copolymers, in that they are selected from 2 a variety of polymers containing at least two blocks linked by 3 chemical valences wherein at least one of said blocks ("A" block) 4 is soluble in the dispersion medium and at least another of said blocks ("B" block) is insoluble in the dispersion medium. The 6 dispersing agent acts to disperse copolymers hereinafter identified:
7 as ' C' copolymers, formed from conjugated dienes and vinyl aromatic 8 monomers which are formed in the presence of the dispersing agent.
9 The insoluble "B" block provides an anchor segment for attachment ~ to the 'C' copolymer, i.e.,the SBR polymer. The soluble "A" block 11 of the dispersing agent provides a sheath around the otherwise 12 insoluble copolymer and maintains the copolymeric product as 13 numerous small discrete particles rather.than an agglomerated or 14 highly coalesced mass.
The soluble "A" block of the dispersing agent comprises about 16 1 to about 15 percent by weight of the total dispersion copolymer I'~; 17 including the dispersing agent and the 'C' copolymer, i.e., the 18 SBR-type random copolymer. The insoluble "B" block of the 19 dispersing agent is prepared in situ during the polymerization of the SBR-type random copolymer, therefore the "B" block has the same 21 composition as the 'C' copolymers, namely the SBR-type random 22 copolymer formed during the dispersion copolymerization process.
23 The total dispersion copolymer composition preferably contains 24 about 2 to about 10 percent by weight of the soluble "A" block and i about 90 to about 98 percent by weight of the insoluble "B" block .
26 and 'C' copolymers most preferably from 4 to 8 weight percent of 1 "A" and 92 to about 96 percent by weight of "B" block and ' C' 2 copolymers being most preferred. The number average molecular 3 weight M" of each '!A" block is preferably at least 500 and a 4 maximum of 200,000, most preferably 1,000 to 100,000.
The number average molecular weights of each "B" block is the 6 same as the 'C' copolymers or SBR-type random polymer, namely at 7 least 20,000 and a maximum of 2,500,000, preferably 75,000 to 8, 500,000.
9,- While it is believed that the soluble "A" can be prepared from 10~~' any monomer providing a soluble block in the dispersing medium 11 subject to known anionic polymerization constraints, it is 12 preferred that the soluble "A" block be selected from a polymer 13 formed by polymerization of conjugated diene monomers or be 14 selected from a copolymer formed by copolymerization of conjugated diene monomers and vinyl substituted aromatic monomers. The 16 soluble "A" block is most preferably selected from a polymer or' a 17 copolymer formed from 75 to 100 parts by weight, preferably .75 to 18 98 parts, of conjugated diene monomer contributed units and 0 to 25 19 parts by weight, preferably 2 to 25 parts, of vinyl substituted aromatic monomer contributed units with the polymer or copolymer 21 blocks being soluble in the hydrocarbon dispersion medium.
22 The insoluble "B" block is produced in the dispersion .
23 polymerization process during the formation of the random copolymer 24 having the same composition as the random copolymer. The insoluble "B" block is anchored to the surface of or the outer layer of the 26 copolymer particle by physical adsorption processes, as for 211~~J3 1 example, by van der Waals forces. Therefore, its main criteria for 2 success as an anchor is to be relatively immiscible in the 3 dispersing -medium. The "B" block can be prepared by the 4 copolymerization of 30 to 65 parts by weight of conjugated diene monomer contributed units and 35 to 70 parts by weight of vinyl 6 substituted aromatic monomer contributed units.
7 The preferred dispersing agents, prepared in situ for use in 8 the present process can be represented by the following structural 9 formula:
( B ~ ~s-ioox~so: asx ) - ( B ~ 30-6sx/ S35-70X ) 11 wherein B' represents butadiene monomer units and S represents 12- styrene monomer units, all blocks of (B'/S) are randomized 13 copolymers of butadiene and styrene monomers. The subscripts 14 display the possible percentage by weight of each monomer in the blocks. Most preferred. diene/vinyl aromatic block .copolymers 16 having (1) a,~first block "A" formed from polybutadiene or~ by the 17 random copolymerization of styrene/butadiene to form an SBR block 18 having less than 25% by weight of styrene contributed content, and 19 (2) a second block "B" formed from a randomized copolymer of styrene/butadiene having a styrene contributed content comparable 21 with the SBR copolymer to be made by the process of. the present 22 invention, namely in the range from 35% to 70% by weight of styrene 23 and 30% to 65% by. weight of butadiene.
24 Diblock A-B dispersing agents are typically prepared utilizing monolithium anionic initiators. The use of dilithium anionic 26 initiators promotes the production of. triblock B-A-B dispersing 1 agents. The dispersing agents prepared in situ and used in the 2 preparation of the SBR copolymers are recovered as a blend with the 3 '.C' copolymers, i.e. SBR copolymers. The dispersing agents are 4 prepared and present in aw amount ranging from about 2 to 50%, preferably 5-35%, and most preferably 10-25% by weight of the total 6 weight of the dispersion copolymer which includes the dispersing 7 agent and the subsequently formed 'C' copolymer, i.e. SBR
8 copolymer.
9 The catalyst systems are anionic initiators for use in preparing the SBR copolymers and the dispersing agent, preferably y 11 any organolith'ium catalyst which is known in the art as being 12 useful in the polymerization of vinyl aromatic hydrocarbons and 13 conjugated dienes. Suitable catalysts which initiate 14 polymerization of the monomer system and dispersing agent include organolithium catalysts which have the formula R(Li)x wherein R
16 represents a hydrocarbyl radical of 1 to 20, preferably 2-8, carbon 17 atoms per R group, and x is an integer of 1-4, preferably 1 or 2.
18 Typical R groups include aliphatic radicals and cycloaliphatic 19 radicals, such as alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, aryl and alkylaryl radicals...
21 Specific examples of R groups for subst.~tution in the above 22 formula include primary, secondary and tertiazy~ groups such as 23 methyl., ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-24 amyl, isoamyl, n-hexyl n-octyl, n-decyl, cyclopentyl-methyl, eyclohexyl-ethyl, cyclopentylethyl, methyl-cyclopentylethyl, 26 cyclopentyl, cyclohexyl, 2,2,1-bicycloheptyl, methylcyclopentyl, ~i~?(~~J
1 dimethylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, 2 dimethylcyclohexyl, ethylcyclohexyl, iso-propylcyclohexyl, and the 3 like.
4 Specific examples of other suitable lithium catalysts include:
phenyllithium, naphthyllithium, 4-butylphenyllithium, p-6 tolyllithium, 4-phenylbutyllithium: 4-butyl-cyclohexyllithium, 4-7 cyclohexylbutyllithium, 1,4-dilithiobutane, 1,10-dilithio-decane, 8 1,20-dilithioeicosane, 1,4-dilithiobenzene, 1,4-, 9 dilithionaphthalene, 1,10-dilithioanthracene, 1,2-dilithio-1y2~-.
diphenylethane, 1,3,5-trilithiopentane,.1,5,15-trilithioeicoxane~;;~1 11 1,3,5-trilithiocyclohexane, 1,3,5,8-tetralithiodecane, 1,5,10,20-12 tetralithioeicosane, 1,2,4,6-tetralithiocyclohexane, 4,4'-13 dilithiobiphenyl, and the like.
14 Mixtures of different lithium catalysts can also be employed, preferably containing one or more;lithium compounds such as R(Li)x.
16 The preferred lithium catalyst for use in the present invention is ~17 n-butyllithium.
18 Other lithium catalysts which can be employed are lithium 19 dialkyl amines, lithium dialkyl pho~sphines, lithium alkyl aryl phosphines, lithium diaryl phosphines and trialkyl tin lithium such 21 as tributyl-tin-lithium:
22 Anionic initiators are typically. employed in amounts ranging 23 from 0.2 millimoles to 100 millimoles of anionic initiator per 24 hundred grams of monomer in the reaction vessel.
I 25 All amounts of anionic initiator are indicated by hundred L
26 grams of monomer or by ratio of components in the instant invention ~1~~'~~3 1 and are considered to be catalytically effective amounts, that is, 2 effective amounts for initiating and conducting polymerization of 3 the dispersing agent and the disclosed monomer systems to produce 4 copolymers of the present invention.
It is preferred to utilize 10 to 50~ by weight of the anionic 6 initiator to prepare the initial "A" block of the dispersing agent.
7 The remaining portion of the initiator is then added during the 8 charging of the monomers to simultaneously produce the "B" block of 9 the dispersing agent and the copolymer from vinyl aromatic monomers ~',10 and conjugated diene monomers..
i11 A SBR copolymer randomizing agent such as an ether or an amine I12 is preferably added to the SBR dispersion polymerization system. as ~13 part of the catalyst system in an amount effective to promote f 14 random copolymerization of the styrene and butadiene monomers.
Other suitable randomizing agents are well known in the art such as 16 sodium or potassium alkoxides~. Randomizing agents are employed in ' 17 the polymerization system in amounts generally ranging from a molar 18 ratio of 1:100 to 1:1 of randomizing agent to anionic initiator.
19 Modifying agents such as ethers, tertiary amines, chelating ethers or amines, and sodium or potassium alkoxides or alkyls, may 21 be added to increase~the.l,2-addition reaction of the diene monomer 22 in the SBR. Such modifying~-agents are well known in the art, such 23 as tetrahydrofuran, tetramethylethylene diamine, d~ethylether and 24 the like, and these modifying agents may be employed in amounts generally ranging from 1:10 to 100:1 molar ratio of the modifier to 26 anionic initiator. The 1,2-addition product can be increased from ~~~~.3~~J .
1 the 5-15% range to as high as 90-100% of the diene monomer units 2 being incorporated into the "A" or "B" block of the dispersing 3 agent and the 'C' copolymer.
4 The preferred 1,2-vinyl content of the "B" block and the 'C' copolymer, i.e. SBR produced in accordance with the process of the 6 instant invention, ranges between 10 to 65% of the diene monomer 7 contributed units. The 1,2-vinyl content in the diene contributed 8 units of the "B" block of the dispersing agent is thus identical to 9 the desired final 1,2-vinyl content of~the.'C' copolymer being produced herein.
11 The reaction mixture utilized in the nonaqueous dispersion 12 polymerization of butadiene and styrene to produce a random 13 copolymer having a styrene content between 35 and 70 percent is 14 comprised.of a liquid nonaqueous dispersion medium, the living "A"
block of a dispersing agent, 30 to 65 parts by weight of butadiene 16 monomer ands 35~ to 70 parts by weight of styrene monomer, and 17 catalyst system. Such a polymerization can be run over a 18 temperature range from 0° up to 150°C. Most generally, it is 19 preferred to utilize a reaction temperature from 40°C. to 110°C.
The reaction, time required in such a polymerization will vary with 21 the reaction.temperature, monomer concentration, catalyst system, 22 and cathlyst level. Generally, this reaction time will vary from 23 about 20 minutes up to about 30 hours. Commonly, it will be 24 preferred to utilize a reaction time from about 1 up to about 6 hours.
21~.~0~~
1 The amount of butadiene and styrene monomers that can be 2 utilized in such a nonaqiieous dispersion polymerization reaction 3 mixture can be varied from about 10 to about 50 weight percent by 4 weight based upon the total reactionmixture. It preferred is to have a final polymer concentration 35 percent ranging from 20 to by 6 weight based upon the total reactionmixture.
7 It is desirable to conduct this polymerizationin an oxygen 8 and moisture free environment. For example, it desirable is to 9 sparge the reaction vessel with dxy nitrogen (or other inert gas) and to run the polymerization under a dry nitrogen atmosphere. The 11 pressure in the reaction system during the polymerization generally 12 will be a function of the inert gas, concentration, polymerization 13 temperature, the monomer concentration; and the vapor pressure of 14 .nonaqueous dispersion medium. The polymerization pressure will usually be maintained within the range between 1.0 and 15 16 atmospheres.
17 The nonaqueous dispersion polymerization can be run in a batch 18 process by simply adding the initiator components to a nonaqueous 19 dispersion medium containing butadiene and styrene monomers and the "A" block of a polymeric dispersing agent to form the reaction 21 .mixture. In a semi-batch process, the monomers are metered into 22 '~ the reactor containing the dispersion medium and an anionic 23 initiator. The "A" block of the dispersing agent can either.be 24 metered into the reactor with the monomers or added to the reactor before the monomers are added or is preferably premade in the 26 reactor as in the following examples. During the course of the ~1~~~~
1 polymerization it will generally be desirable to provide some form 2 of agitation to the reaction mixture, such as stirring, shaking, or 3 tumbling. A short stopping agent such as .an alcohol may be 4 employed to terminate the polymerization after the desired reaction time or at the desired percent conversion of monomers to copolymer.
6 In general, the conversion of monomers inta polymers is allowed to 7 proceed to about completion. An appropriate antioxidant can be 8 added at this stage of the process.
9 The nonaqueous dispersions formed in this polymerization process have a solids concentration ranging between about l0 to 50 11 weight percent and are quite fluid. This fluidity permits greatly 12 improved heat transfer as compared to the fluidity of.solutions of 13 SBR copolymers prepared using solution polymerization techniques.
14 Due to the relative fluidity of these nonaqueous dispersions, both a higher molecular weight polymer can be produced and the r16 concentration of dispersed SBR copolymers in the medium can be 17 increased by 25 to 100% or more over the maximum allowable 18 concentrations in solution polymerization techniques.
19 The elastomeric SBR copolymer can be recovered from the hydrocarbon solvent by steam desolventization or by drum drying 21, techniques thus providing energy savings due to higher solids 22 levels. By proper control of particle size, the polymers can be .23 recovered by filtration or centrifugation techniques.
24 The recovered copolymer products, depending on their molecular weights and compositions, can be used for a variety of goods such 26 as tires and various rubber molded products.
1 It is believed that one skilled in the art can, using the 2 preceding description, utilize the present invention to its fullest 3 extent. The following preferred. specific embodiments are, 4 therefore, to be construed as merely illustrative of the catalyst system and the polymerization process of the present invention.
6 All percentages identified in the examples are by weight: unless-? otherwise indicated.
8 EXAMPLES 1 and 2 i 9 ~ Preparation of "A" Block of Dispersing Agent A one gallon reactor was charged with 30 g. of 10 % styrene/90%
11 butadiene in 500 ml of hexane, 0.8 mmole of n-butyllithium and 3.2 12 mmoles of tetrahydrofuran (THF). The reactor was heated to and f 13 maintained at 95~C. for ten minutes, after which time 5.mmoles of 14 isopropanol were added to terminate the.reaction to provide the "A"
block of a dispersing agent. This procedure was repeated a second 16 time and the properties of the first and second recovered "A"
17 blocks are as follows as~shown in Examples 1 and 2.
3 EXAMPLE NO. 1 2 4 Yield % 68.7 80.0 Mn (GPC) 80,400 57,000 6 MW~Mn 1.38 1.45 7 Vinyl % 18.9 18.9 8 Styrene % 7.2 7.7 9 Tg (DSC) C. -84 -82 12In si tu dispersion polymerization reactions were conducted 13utilizing reactants and in accordance ith conditions identified w 14in Tables II and III in Examples 3 to 12. The "A" blocks of 15dispersing agents used in each example were prepared in hexane 16following the same procedure of Example 1 utilizing the reactants 17and conditions in Tables II and III, displayed under Step 18however th e blocks were not terminated. Examples 3 to 7 employed 19n-butyllithium examples 8 to 12 employed as the RLi initiator and 20tributyl-SnLi as the RLi initiator in the amounts indicated.
The 21modifiers utilized in these examples included tetrahydrofuran 22(THF), bis oxolanyl propane (OOPS) and tetramethylethylene diamine 23(TMEDA) in amounts identified as modifiermillimoles (MOD mmol).
1 After formation of the first living "A" block copolymer in 2 each example, the living "A" block copolymer in solution as 3 prepared in Step 1 and a subsequent charge identified under Step 2 4 in Tables II and III of 1,3-butadiene (1,3-BD) in 24.90 hexane solution and styrene in 33% hexane solution were blended along 6 with additional anionic initiator (RLi) in the reactor either in a 7 batch or semibatch (SEMI) reaction (RXN TYPE). Each reaction 8 proceeded at the indicated time and temperature. Polymerizations 9 were terminated in Examples 3 to 7 by the addition of isopropanol and were terminated in Examples 8 to 12 by the addition of 11 dibutyl-SnCl2. These polymerization processes yielded an A-B
12 diblock copolymer dispersing agent which was formed in situ with a 13 random copolymer (identified in Tables II and III as 'C' polymer).
14 The composition of the 'C' polymer and the "B" block were equivalent. Good dispersions were formed in all examples at both 16 the reaction temperature (hot) and at room temperature (cold).
17 Product properties of the recovered blends of A-B diblock 18 dispersing agent and random copolymer are displayed under product 19 properties on Tables II and III. The solids levels of the resultant dispersions produced in Examples 3 to 12 ranged between 21 21 to 25 percent.
N ~ ~ tJ~
TABLE II
IN SITU DISPERSION SBR USING n-BuLi 1 Example No. 3 4 5 6 7 4 'A' BLOCK PREPARATION
1,3-BD (g) 24 27 13.5 13.5 27 6 STYRENE (g) 3 3 1.5 1.5 3 7 RLi (mmol) 0.7 1:-0 1.0 1.0 1.0 9 MOD. (mmol) 8.0 4.0 0.5 0.3 0.4 TEMP. (F.) 150 200 200 200 200 11 TIME (min.) 60 10 10 10 10 'B' BLOCK & POLY, ~PARATION
' C' E~
16 1,3-BD (g) 266 250 155 155 226' 17 STYRENE (g) 199 204 303 303 228 18 RLi (mmol) 3.0 3.0 4.2 2.2 3.0 19 MOD. (mmol) ___ ___ ___ ___ ___ RXN TYPE SEMI BATCH SEMI SEMI SEMI
21 TIME (min.) 80 150 70 80 95 22 TEMP. (F.) 200 277 200 200 200 ~
23 max '~ PRODUCT PROPERTIES
27 Ts ~('C. ) -47 -18 +5 -4 -34 %VINYL 17.2 47.2 39.5 35.0 20.5 31 (BD=100) 32 %STYRENE 36.8 45.6 67.7 67.3 51.1 33 %BLOCK ~ 4.4 26.1 45.9 42.4 27.3 34 (STY=100) 37 M"/10-3 205 158 127.2 177.3 165.1 38 M"/M" 1.32 1.25 1.6 1.59 1.44 PHYSICAL STATE OF DISPERSION
41 .
43 VISC. VISC. VISC. VISC. VISC.
COLD LOW LOW LOW LOW LOW
46 VISC. VISC. VISC. VISC. VISC.
~1~2~;~s TABLE III
IN SITU DISPERSION SBR USING BU3SnLi . Example No. 8 9 10 11 12 4 'A' BLOCK PREPARATION
1,3-BD (g) 24 36 27 27 27 6 STYRENE (g) 3 4 3 3 3 7 RLi (mmol) 0:7 0.8 0.8 0.8 0.8 9 MOD. (mmol) 3.5 1.6 3.2 3.2 3.2 TEMP. (F.) 150 195 200 200 200 11 TIME (min.) 45 10 10 10 10 'B' BLOCK & POLYMER PREPARATION
' C' ~
~
16 1,3-BD (g 266 . 276 267. 271 280 ) 17 STYRENE (g) 199 184 193 189 180 18 RLi (mmol) 4.1 4.2 4.2 4.2 4.2, 19 MOD. (mmol) 20.5 8.4 8.4 8.4 8.4~
RXN TYPE SEMI SEMI SEMI SEMI SEMI
21 TIME (min.) 75 67 90 90 85 22 TEMP. 'F. 190 ~ 200 200 200 200 26 Tg ('C.) -34 -47 -39 -39 -43 ~
29 %VINYL 23.2 17.6 18.7 18.9 19.2 (BD=100) 31 %STYRENE 40.0 36.4 39.5 38.6 37.3 32 %BLOCK 3.8 6.4 8.9 9.6 9.1 33 (STY=100) GPC
36 M"/10-3 196.2 180.4 ~ 65.7 160. 8 154.1 ', M"/M" 1.49 1.52 ~ 1..54 1.51 1.55 139 PHYSICAL STATEOF DISPERSION .
- ~
~~~
!41 ~ HOT MEDIUM MEDIUM LOW LOW MEDIUM
'~,42 VISC. VISC. VISC. VISC. VISC.
~~
',44COLD IAW MEDIUM LOW LOW LOW
145 VISC. VISC. VISC. VISC. VISC.
~~l~~~J
1 While certain representative embodiments and details have been 2 shown for the purpose of illustrating the invention, it will be 3 apparent to those skilled in the art that various changes and 4 modifications may be made therein without departing from the scope of the invention.
Claims (10)
1. A process for the preparation of a random copolymer by the dispersion random copolymerization of a mixture consisting of 35 to 70% by weight of at least one vinyl aromatic monomer, excluding vinyl substituted aromatic monomers wherein the homopolymer of the monomer is soluble in linear alkane solvents and the copolymer of the monomer with dime is soluble, and 30 to 65% by weight of at least one conjugated diene monomer comprising carrying out the copolymerization in a hydrocarbon dispersing medium, the dispersing medium comprising at least 70% by weight of non-cyclic aliphatic hydrocarbons in the presence of a block copolymer dispersing agent being present in an amount ranging from 2 to 50% by weight of the total weight of the dispersion copolymer and said block copolymer dispersing agent having a preformed block and at least one block formed in situ during the copolymerization of the dispersion copolymer and a catalytically effective amount of an anionic initiator, the preformed block being soluble in the dispersing medium and comprising 1 to 15% by weight of the total weight of the dispersion copolymer including the dispersing agent and the random copolymer and the block formed in situ being insoluble in the dispersing medium and having the structure and the number average molecular weight ranging from 20,000 to
2,500,000 of the random copolymer, the solubility parameter of the random copolymer being at least 1.9 greater than the solubility parameter of the dispersing medium.
2. The process as defined in claim 1 wherein the non-cyclic aliphatic hydrocarbon is n-hexane.
2. The process as defined in claim 1 wherein the non-cyclic aliphatic hydrocarbon is n-hexane.
3. The process as defined in claim 1 wherein the dispersion copolymer is formed by the copolymerization of 40 to 60% by weight of the at least one vinyl aromatic monomer and 40 to 60% by weight of the at least one conjugated dime monomer.
4. The process as defined in claim 1 wherein the block copolymer dispersing agent is formed in situ during the copolymerization process by adding the preformed block formed prior to the dispersion copolymerization by the copolymerization of 0 to 25% by weight of the at least one vinyl aromatic monomer and 75 to 100% by weight of the at least one conjugated dime monomer in the presence of an anionic initiator, the preformed block being soluble in the dispersing hydrocarbon medium.
5. The process as deffined in claim 4 wherein the block copolymer dispersing agent is an A-B diblock copolymer having a dispersing medium soluble preformed block A and a dispersing medium insoluble block B formed in situ by the polymerization of 35 to 70% by weight of the at least one vinyl aromatic monomer and 30 to 65% by weight of the at least one conjugated dime monomer.
6. The process as deffined in claim 5 wherein the block copolymer dispersing agent is an A-B diblock copolymer obtained by using a monolithium anionic initiator.
7. The process as defined in claim 4 wherein the block copolymer dispersing agent formed in situ is a triblock copolymer resin obtained by using a dilithium anionic initiator.
8. The process as defined in claim 1 wherein the vinyl aromatic monomer is styrene.
9. The process as defined in claim 1 wherein the conjugated dime is 1,3-butadiene.
10. The process of claim 1 wherein the dispersion copolymer formed in situ by the dispersion copolymerization process is present in concentrations ranging between 10 to 50 weight percent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/995,118 US5331035A (en) | 1992-12-22 | 1992-12-22 | Process for the preparation of in situ dispersion of copolymers |
| US995,118 | 1992-12-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2112003A1 CA2112003A1 (en) | 1994-06-23 |
| CA2112003C true CA2112003C (en) | 2005-06-14 |
Family
ID=25541423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002112003A Expired - Fee Related CA2112003C (en) | 1992-12-22 | 1993-12-21 | Process for the preparation of in situ dispersion of copolymers |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5331035A (en) |
| EP (1) | EP0603668B1 (en) |
| JP (1) | JP3470979B2 (en) |
| CA (1) | CA2112003C (en) |
| DE (1) | DE69321086T2 (en) |
| ES (1) | ES2120470T3 (en) |
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|---|---|---|---|---|
| US5891947A (en) * | 1992-12-22 | 1999-04-06 | Bridgestone Corporation | In-situ anionic continuous dispersion polymerization process |
| US5614579A (en) * | 1992-12-22 | 1997-03-25 | Bridgestone Corporation | Process for the preparation of tapered copolymers via in situ dispersion |
| DE19528717A1 (en) * | 1995-08-04 | 1997-02-06 | Basf Ag | Polymer particles and process for their manufacture |
| US6008295A (en) * | 1997-07-11 | 1999-12-28 | Bridgestone Corporation | Diene polymers and copolymers incorporating partial coupling and terminals formed from hydrocarboxysilane compounds |
| US6184287B1 (en) | 1999-01-26 | 2001-02-06 | Omnova Solutions Inc. | Polymeric latexes prepared in the presence of 2-acrylamido-2-methylpropanesulfonate |
| US6956084B2 (en) * | 2001-10-04 | 2005-10-18 | Bridgestone Corporation | Nano-particle preparation and applications |
| US6437050B1 (en) | 2001-10-04 | 2002-08-20 | Bridgestone Corporation | Nano-particle preparation and applications |
| US6706823B2 (en) | 2001-12-31 | 2004-03-16 | Bridgestone Corporation | Conductive gels |
| US7576155B2 (en) | 2002-12-18 | 2009-08-18 | Bridgestone Corporation | Method for clay exfoliation, compositions therefore, and modified rubber containing same |
| US6875818B2 (en) | 2003-01-16 | 2005-04-05 | Bridgestone Corporation | Polymer nano-strings |
| US7205370B2 (en) | 2004-01-12 | 2007-04-17 | Bridgestone Corporation | Polymeric nano-particles of flower-like structure and applications |
| US7112369B2 (en) * | 2004-03-02 | 2006-09-26 | Bridgestone Corporation | Nano-sized polymer-metal composites |
| US7718737B2 (en) | 2004-03-02 | 2010-05-18 | Bridgestone Corporation | Rubber composition containing functionalized polymer nanoparticles |
| US8063142B2 (en) | 2004-03-02 | 2011-11-22 | Bridgestone Corporation | Method of making nano-particles of selected size distribution |
| US20050282956A1 (en) * | 2004-06-21 | 2005-12-22 | Xiaorong Wang | Reversible polymer/metal nano-composites and method for manufacturing same |
| US7998554B2 (en) | 2004-07-06 | 2011-08-16 | Bridgestone Corporation | Hydrophobic surfaces with nanoparticles |
| US7572855B2 (en) | 2005-01-28 | 2009-08-11 | Bridgestone Corporation | Nano-composite and compositions manufactured thereof |
| US7579398B2 (en) | 2005-02-02 | 2009-08-25 | Bridgestone Corporation | Nano-composite and compositions therefrom |
| US7659342B2 (en) | 2005-02-03 | 2010-02-09 | Bridgestone Corporation | Polymer nano-particle with polar core and method for manufacturing same |
| US7538159B2 (en) | 2005-12-16 | 2009-05-26 | Bridgestone Corporation | Nanoparticles with controlled architecture and method thereof |
| US9061900B2 (en) | 2005-12-16 | 2015-06-23 | Bridgestone Corporation | Combined use of liquid polymer and polymeric nanoparticles for rubber applications |
| US7884160B2 (en) | 2005-12-19 | 2011-02-08 | Bridgestone Corporation | Non-spherical nanoparticles made from living triblock polymer chains |
| US8288473B2 (en) | 2005-12-19 | 2012-10-16 | Bridgestone Corporation | Disk-like nanoparticles |
| US7601772B2 (en) * | 2005-12-20 | 2009-10-13 | Bridgestone Corporation | Nano-composite and method thereof |
| US7560510B2 (en) | 2005-12-20 | 2009-07-14 | Bridgestone Corporation | Nano-sized inorganic metal particles, preparation thereof, and application thereof in improving rubber properties |
| US8697775B2 (en) | 2005-12-20 | 2014-04-15 | Bridgestone Corporation | Vulcanizable nanoparticles having a core with a high glass transition temperature |
| US8877250B2 (en) | 2005-12-20 | 2014-11-04 | Bridgestone Corporation | Hollow nano-particles and method thereof |
| US7935184B2 (en) | 2006-06-19 | 2011-05-03 | Bridgestone Corporation | Method of preparing imidazolium surfactants |
| WO2008014464A2 (en) | 2006-07-28 | 2008-01-31 | Bridgestone Corporation | Polymeric core-shell nanoparticles with interphase region |
| US7597959B2 (en) | 2006-12-19 | 2009-10-06 | Bridgestone Corporation | Core-shell fluorescent nanoparticles |
| US7649049B2 (en) | 2006-12-20 | 2010-01-19 | Bridgestone Corporation | Rubber composition containing a polymer nanoparticle |
| US7829624B2 (en) | 2007-06-29 | 2010-11-09 | Bridgestone Corporation | One-pot synthesis of nanoparticles and liquid polymer for rubber applications |
| US9732178B1 (en) | 2008-07-24 | 2017-08-15 | Bridgestone Corporation | Block copolymers including high vinyl segments |
| US8846819B2 (en) | 2008-12-31 | 2014-09-30 | Bridgestone Corporation | Core-first nanoparticle formation process, nanoparticle, and composition |
| US9062144B2 (en) | 2009-04-03 | 2015-06-23 | Bridgestone Corporation | Hairy polymeric nanoparticles with first and second shell block polymer arms |
| US9115222B2 (en) | 2009-12-29 | 2015-08-25 | Bridgestone Corporation | Well defined, highly crosslinked nanoparticles and method for making same |
| US9428604B1 (en) | 2011-12-30 | 2016-08-30 | Bridgestone Corporation | Nanoparticle fillers and methods of mixing into elastomers |
| WO2021076640A1 (en) * | 2019-10-14 | 2021-04-22 | Bridgestone Americas Tire Operations, Llc | Anionic dispersion polymerization process to make random copolymer rubber |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL112597C (en) * | 1958-11-05 | 1900-01-01 | ||
| FR2245686A1 (en) * | 1973-06-29 | 1975-04-25 | Voron V | Polystyrene-polybutadiene block copolymers prodn - by block copolymsg. butadiene and styrene onto living poly-alpha-methyl styrene block, with good thermal stability |
| US4098980A (en) * | 1976-06-24 | 1978-07-04 | The Goodyear Tire & Rubber Company | Non-aqueous dispersion polymerization of conjugated diolefins |
| DE3481426D1 (en) * | 1983-08-22 | 1990-04-05 | Dow Chemical Co | METHOD FOR PRODUCING COPOLYMERISATES FROM ISOPROPENYLAROMATIC AND VINYLAROMATIC MONOMERS. |
| US4871814A (en) * | 1986-08-28 | 1989-10-03 | Mobil Oil Corporation | High impact, highly transparent linear styrene-diene block copolymers with five or more blocks and their preparations by anionic dispersion polymerization |
| US4829135A (en) * | 1987-12-29 | 1989-05-09 | Mobil Oil Corporation | Multi-stage anionic dispersion homopolymerization to form microparticles with narrow size distribution |
-
1992
- 1992-12-22 US US07/995,118 patent/US5331035A/en not_active Expired - Lifetime
-
1993
- 1993-12-09 DE DE69321086T patent/DE69321086T2/en not_active Expired - Lifetime
- 1993-12-09 EP EP93119889A patent/EP0603668B1/en not_active Expired - Lifetime
- 1993-12-09 ES ES93119889T patent/ES2120470T3/en not_active Expired - Lifetime
- 1993-12-20 JP JP34455093A patent/JP3470979B2/en not_active Expired - Fee Related
- 1993-12-21 CA CA002112003A patent/CA2112003C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2112003A1 (en) | 1994-06-23 |
| DE69321086D1 (en) | 1998-10-22 |
| JP3470979B2 (en) | 2003-11-25 |
| US5331035A (en) | 1994-07-19 |
| JPH06206918A (en) | 1994-07-26 |
| EP0603668A1 (en) | 1994-06-29 |
| EP0603668B1 (en) | 1998-09-16 |
| ES2120470T3 (en) | 1998-11-01 |
| DE69321086T2 (en) | 1999-02-25 |
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