CA1102473A - Tough polyblends with improved heat distortion resistance - Google Patents

Abstract

APPLICATION FOR
LETTERS PATENT
FOR
TOUGH POLYBLENDS WITH IMPROVED HEAT
DISTORTION RESISTANCE

ABSTRACT OF THE DISCLOSURE
Polyblends are disclosed which comprise an ABS polymer blended with a rubber modified polymer of a monoalkenyl aromatic monomer and an unsaturated dicarboxylic acid anhydride.

Description

~2~7;~
, Td~GH POLYBLENDS WITH IMPROV~D HEAT DISTOR~ION RESISTANCE
BACKGROUND OF THE INVENTION
This invention relates to polyblends and speci~ically to polyblends of ABS polymers with styrenetmaleic anhydride copolymers 5 having a rubber modifier incorporated therein.
ABS polymers are formed by the polymerizatlon of styrene and acrylonitrile in the presence of a diene rubber such as poly-butadiene. They may be made by mass, suspensio~ or emulsion poly-merization techniques. The diene rubber is present as a substrate 10 grafted with a styrene/acrylonitrile superstrate. A styrene~
acrylonitrile matrix is usually formed simultaneously with the gra~ting reaction. Further matrix may be added subsequently in a blendlng operation to obtaln the desired formulation.
Besides the compositions described above, the term "ABS
15 polymer" is ~ften used~to cover variations in this formulation through substitution of other copolymeri~able monomers, in whole or in part, for one or more Or the components o~ standard ABS. Thus, the acrylonitrile can be wholly or partially substituted for example~
by methacrylonitrile; `~
20 polybutadiene can be replaced~with a wide range of other rubbers having a Tg (glass transitlon temperature) below 0C. and preferably below ~30C,; and styrene can be replaced by substituted styrene such as halostyrenes, ~ -methyl styrene and the like. All such variations are embraced by the term ABS polymer as lt is used herein.
The term '!ABSI' is conventiona}ly used to describe com-posltions comprising the "styrene" and '~acrylonitrile" monomer com-ponents in a weight ratio of from 80:20 to 60:40.
ABS polymers are very well kno~rn in the field of molding materials as being suitable for the production of tough, moldable 30 materials with good surface properties. ABS is adapted for use in ~Z~73 08~ 0373A

such diverse ~ields as automotive parts, housings ror ma~or appliances such as refrlgerators and washing machines, television cabinets, body ~ork for small appliances such as blends, mixers, pocket calculators, radlos, telephones and containers ~or ~ood~
stuf~s. The polymers however, have a disadvantage in that they generally have too low a heat distortion tempe~ature ~or certain uses where the item made from the polymer is expected to operate at a relatively high temperature, without becoming distorted. This disadvantage somewhat limlts the range o~ potential end-u~es ~or whlch ABS is adapted. The present invention provides a composition based on A~S which has a signlficantly higher heat d1stortion tem-perature than ABS and is therefore capable of performing adequately under higher temperature conditions while retaining much o~ the toughness that characterizes ABS polymers.

The production of ABS is very well known in the art and is described in such patents as U.S. Patents 3,509,237; 3,509,238;
3,851,014; and 3,903,200. A very comprehensive treatment of the sub~ect is folmd in "ABS Plastics" by C. H. Basdekis (Rheinhold-20 1964). It has been ~lended with a very wide range of other polymersranging from polyvinyl chloride (U.S.P. 2,802,809) to polycarbonates (U.S.P. 3,130,177). In U.S.P. 3,642,949 an ABS polymer is blended with a copolymer of a vinylaromatic monomer (95~65 parts by welght) and an unsaturated dicarboxylic anhydride, or an lmide or N-alkyl-25 imide derivative of such an anhydride (5-35 parts by wei~ht). Such polymers provide moldlng cornpositions with improved heat dlstortlon characteristics but the improvement ls obtalned at the expense of a signi~icant decrease ln the impact stren~th o~ the ABS polymer.
I~ is further known that styrene may be copolymerized with malelc anhydride using special techniques such as are described in U.s.P. 2,971,939; 2,989,517; 3,336,267 and British Patent 1,234,395.

~2~73 It is also ~enerally known that the incorporation of rubber in polystyrene results in an improvement in impact strength especially when the styrene is polymerized in the presence of the rubber. Such a product is conventionally called high impact poly-styrene and comprises a rubber substrate grafted wlth the poly-merizing monomer, dlspersed as particles in a matrix o~ the styrene polymer. Rubber-modifled styrene~maleic anhydride polymers having this conventional structure are described ln U.S.P. 3,919,354.
A polyblend has now been dlscovered which exhlbits tough-ness and high heat distortion temperature and is therefore, parti-cularly use~ul for producing molded ob~ects.
S~ATEMENT OF THE INVENTION
The present invention provides a polyblend comprising:
A. from 10 to gO% by weight of an ABS polymer having a rubber con-tent in the range of 5 to 70% by-weightj and B. from 90 to 10% by weight of a polymeric composition comprising 1) a rubber substrate polymer having a glass transition tempera-ture below 0C.; and

2) a superstrate polymer grafted onto the rubber substrate which comprises from 40 to 85% by weight of a monoalkenyl aromatic monomer and frorn 15 to 35% by weight of an un-saturated dicarboxylic acid anhydride.
the amount of the rubber substrate being ~rom 2 to 30% by weight o~ the poly~eric composition, wherein the total amount of rubber in the polyblend is ln the range of rrom 5 to 40g of the total weight of the polyblend, with the proviso that each of components A and B, contribute at least 5% of the total amount of rubber in the polyblend, The superstrate polymer of component B can optionally con-tain O to 30% by weight of an additional termonomer that is co-1~ 73 08-12~0373A
polymerizable with the other monomers in the presence o~ the rubber substrate.
Dur~ng graft polymerization of the superstrate onto the substrate polymer it,is ~ound that some portions o~ the monomers polymerize together to form a matrix polymer without becoming grafted on t~ the substrate. The present invention also contem-plat&s the presence of such matrix polymers in both the polymeric composition ~component B) and the hBS polymer (component A).
It is surprisingly found that tbe combination of' heat distortion temperature and high impact strength Or the above poly-blends ls not obtained with the compositions of the prior art. As an example, it is found that a blend of ABS and a polybutadiene rubber reinforoed styrene/maleic anhydride copolymer has better impact strength than does either a blend of ABS with a styrene/
maleic anhydride copolymer or a styrene~acrylonitrile copolymer blended with a polybutadiene rubber modified styrene/maleic anhydride copolymer, even when each composition is formulated to give the same overall proportions of rubber in the polyblend and the same relative proportions of styrene and maleic anhydride. Moreover, this improved impact strength is obtained with only a minor reduc-tlon in the heat dlstortion temperature consequent on the overall reduction of the maleic anhydride content. Since it is believed that the rubber i9 the toughness pr~ducing component and ~he malelc anhydride is the comp'onent improving the heat distortion temperature, this result ls indeed surprising and lndicative of synergism within the polyblend. The evidence for this conclusion is set forth in some detail in the Examples presented hereinbelow.
In addition to the above polyblends, certain Or the rubber-modlfied terpo,lymers which may be blended with the ABS to produce the polyblends, are themselves use~ul per se and possess unexpectedly advantageous properties.

_ 5 _ 08-12-0373A
ABS POLYMER
.
As ~ndicated above the term "ABS polymer" is intended to embrace the variations of the components of such compositions that are known in the art.
One such variation which is particularly useful in de-signing the polyblend for a speclfic end-use is the production of ABS by controlling the amount of matrix polymer formed durlng the gra~t polymerization of the styrene and acrylonikrlle components on to the rubber substrate polymer. Additional separa~ely prepared matrlx polymer of the same or different composition can be added to the ABS in order to achieve some degr~ee of variation of the pro-perties of the final product. ~his approach permits some flexi-bility in the final composition of the ABS polymer. Thus, the grafted substrate may be for exampla; polybutadiene grafted with styrene and acrylonltrile while the separately prepared matrix polymer is a copolymer of alpha-methyl-styrene with acrylonitrile.
The grafted rubber may be in the form of particles with a narrow or broad size-range or it may contain particles in two different size ranges ln accordance with the teachings in V.S.P.

3,50g,237 (incorporated herein by reference), so as to obtain a good balance of strength and good surface qualities.
It is therefore sometimas preferred that from 5 to 50Z
and preferably from 10 to 30% by weight of the rubber in the ABS
polymer ls in the form of grafted rubber particles with a weight a~erage partlcle size of about 0.8 to 4.0 microns, the balance of the rubber being in the form of grafted partlcles with a weight average'partlcle size of about 0.1 to 0.25 micron.
Other preferred compositions have all the rubber present as grafted particles with narrow particle size distribution and'a weight average size in the range of from 0.3 to 0.8 micron and 2~3 preferably 0.4 to 0;7 while still others have grafted rubber parti-cles with a broad particle ~ize distribution about a weight average size of from 0.3 to o.6 micron. Each variation has specific bene-fits to confer in terms of phys~cal properties and surface characteristics.
The amount of rubber (ungrafted basls) in the ABS com-ponent is in the range of from 5 to 70% and preferably ~rom 5 to 50%
based on the total weight of ABS (grafted rubber plus matrix polymer).
The ABS component provides at least 5% and pre~erably at least loZ
of the total weight of rubber tun~rafted basls) in the polyblend.
As indicated above the term "ABSn as used herein is under-stood to indicate a polymer in which the styrene and acrylonitrile components (or their conventional partial or complete replacements) are present in weight ratios of from 80:20 to 60:40 such as from 15 75:25 to 65:35. These ratios are preferably also applicable to the super~trate and matrix polymers separately.
The preferred weight ratio of the rubber substrate to . . .
graft superstrate is from 80:20 to 40:80 and more preferably 60:40 to 40:60.
POLYME~IC COMPOSITION
The polymeric composition blended with the ABS to form the polyblend of the~invention comprises a rubber substrate polymer having a glass transikion temperature (Tg) below 0C. and a super-strate polymer grafted thereon which comprises from llO to 85% such as from 70-80% by weight of a monoalkenyl aromatic monomer and from 15 to 35~0 and preferably 20-30% by weight of an unsaturated di-carboxylic acid anhydride;
During the graft polymerization of the superstrate on the substrate rubber, it i8 frequently found that some portions of the monomers polymerize together to form a matrix polymer without be-08-12-0~73A
coming gra~ted to the substrate. The presence of such matrix polymer is also contemplated in this invention. It is of course, not necessary that all the matrix polymer be formed during the grafting process. It is within the purview of this invention to 5 produce the polymer compositlon by adding separately prepared matrlx polymer to the grafted rubber substrate to glve any desired rubber level. Any matrix polymer so added is o~ course subject to the same composition~l range restrictions as apply to the superstrate polymer though they need not be identical compositions.
The rubber substrate component of the polymeric composl-tlon can be selected from a wide range of alternatlves including butadiene polymers and copolymers, polyisoprene, polychloroprene, polyacrylate rubbers, and ethylene/propylene~diene rubber ~EPDM), polypentenamer and ethylene/vinyl acetate rubbers. Copolymers of cyclopentene with a minor proportion of a non-cyclic ~-olefin such as for example a copolymer of 55 to 95% bf cyclopentene with from 5 to 45% of ethylene are particularly useful. Other rubbers which have a Tg below 0C. and which may be gra~ted with the monomers used to produce the polymeric composition can readily be supplied by the skilled reader. The preferred rubbers have a Tg below about -30C.
and the most pre~erred are polybutadiene and copolymers of butadiene with up to 40~ by weight of a styrene or acrylonitrile comonomer.
The ~onoalkenyl aromatic monomer used in component B is preferably styrene but styrene derivatives such as chlorostyrene, vinyl toluene, alpha-methyl styrene, alpha-metbyl vinyl toluene, 2,4-dichlorostyrene and 2-chloro-4-methylstyrene may be substituted for styrene in whole or in part if desired.
The unsaturated dicarboxylic acid anhydride is most pre~
ferably maleic anhydride though any of the homologues of maleic anhydride such as ltaconic, citraconic and aconitic anhydrides can also be used.

2~173 0~-12-0373A -- B -The polymeric composltion can rurther comprlse up to 30%
by weight (based on the polymerizable monomer) Or a Copolymerlzable monomer. The selection Or this copolymerizable monomer may be inrluenced by ractors such as the ease with which the copolymeriza-tion takes place, the compatibil1ty of the monom~rs, phase di~rerencesand the like. Copolymerizable monomers can be identiried among monomers such as ole~ins, allphatlc or aromatic esters o~ un-saturated acids, unsaturated ethers3 unsaturated nitriles9 vinyl halides, vinyl esters and the like.
In practice a pre~erred group Or copolymeri~able monomers lncludes C4 to C6 ~-olefins, Cl to C3 al~yl esters Or tmeth)acrylic acid, methacrylonitrile and acrylonltrile.
Where the copolymerizabIe monomer is an olerin it can ~or e~ample, be cyclohexene, n-hexene, isopentene, n-pentene, n-butene or isobutylene. The acrylate ester can be methyl acrylate, ethyl acrylate, propyl acrylate; the methacrylate esters, which are generally preferred over the acrylate esters~ methyl methacrylate, ethyl methacrylate or propyl methacrylate. The prererred copoly-merizable monomers are acrylonitrilej methyl methacrylate and iso-~20 butylene, ;
The poIymeric composition ls conveniently prepared by dissolvlng the rubber in a solution.o~ the monoalkyl aromatic com-ponent and, if present, the copolymerizable monomer in a suitable solvent, and then polymerizing the solution with the anhydrlde com-ponent in the manner described in, for example, V.S.P. 2~971~93U.S.P. 3,336,267 and U.S.P. 3,919,354.

Where a termonomer is present a polymerization schedule may be devised on the basis Or the relative~reactivlties Or the monomers, Typical schedules involve preparing an initial reac~ion _ 9 _ mixture comprising a solvent, the bulk of the alk2nDl aromatic monomers, a very small amount (or none) of the Qnhydride monomer and the major proportion of the termonomer. The rubber ls dissolved in ~his mixture and the balance of the monomers is added slowly durin~ the polymerizatlon.
The amount o~ rubber substrate (ungra~ted basls) in the polymerlc composition, ~htCh includes the grafted substrate and any ma~rix polymer present, is in the ra~ge from 2 to ~0% by weight based on the weight of the polymeric composltion. Preferably, how-ever, the rubber sub9trate represents from 5 to 25% o~ the weight o~the polymeric comp~sition.
The ratio of proportions by weight of monoalkenyl aromatic mOnQmer to unsaturated dicarboxylic acid anhydride poly-merized together in the presence of the rubber and in the absence of the copolymeri~able termonomer to rorm the polymeric composition can be from 85:15 to 65:35, but a ratio of from 80:20 to 70:30 is particularly pre~erred. The maleic anhydride compositlonal range is in part determined by the need to provide substantial compatibi-lity with the ABS component. It is found that the ABS ~which has 20 40% by weight of AN) is increasingly incompatlble with styrene/
maleic anhydride polymers as the maleic anhydride content is reduced belo~ 15% and processabillty conslderations place an upper llmit on the amount of the anhydrlde that can practicably be used~
Where a termonomer ~s present, the preferred proportions depend on the actual termonomer. Thus, where the te~monomer is a C4 to C6 ~-olefin such as i~obutylene it i~ preferred that it be present in an amount from 2 to 10~ by weight based on the copoly-merized monomers. Where the termonomer is an alkyl ester of (me~h) acryllc acld such as methylmethacrylate or an unsaturated nitrile such as acrylonitrile, the corresponding amount is preferably ~rom Z~73 2 to 20% by weight. Rubber-modi~ied terpolymers ~aving these pre~
ferred proportions of the specified termonomers, i.e., 2 to lOg for the ~-olefin, and 2-20% ~or the (meth)acrylate esters and nitriles, are themselves useful per se as molding compositions havlng unexpectedly advantageous properties such as, in the case of the methyl methacrylate terpolymerl improved tensile stren~th and gloss over conventional RM-SMA.
The polyblend of the invention comprises from 90 to 10%
by weight of an ABS polymer (A) and from 10 to 90% by weight of the polymerlc compositlon (B) but the preferred welght proportiOns are from 75 to 25 to and from 25 to 75 of B. Withln these ranges component A and component B may be chosen to emphasize the heat dis-tortion temperature (by increasing component B and~or the aMount of anhydride therein) or impact properties (by increasing component A and/or the amount of rubber substrate in~both A and ~).
The rubber (ungrafted basis) provided by A and B together comprlses from 5 to 40% and preferably10 to 30% by welght of the polyblend and is distributed between the first and second composi-tlons such that each contributes at least 5% and preferably at least 10% of the total rubber content measured as ungrafted substrate.
Usually, the ma~or proportion of the rubber~present measured as ungrafted substrate, is contributed by the flrst polymeric composit1on The polyblend can contain other additives such as for example, additional ungrafted rubber components, flame retardants, smoke suppressants, antioxidants, stabilizers, lubrioants, anti-static additives, colorants and fillers.
The blending of components A and B i~ most conveniently achieved by extrusion or by compounding in~a Banbury, Brabender or similar mixing device, Care, however, must be taken that the tem-perature at which the components are blended does not exceed thetemperature at which e~ther component decomposes.

DRSCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is further described by re~erence to the followlng Examples which are for the purposes of illustra-tion only and are not intended to imply any llmitation o~ the scope of the invention.
The Examples illustrate the result5 of varying the com-position o~ the polyblend and the surprisin~ advantages obtained by provlding that both components Or the polyblend are rubber-modi~ied, even when the total amount of rubber in the polyblend is Icept con-stant. They also show that this phenomenon i5 apparent even whenthe relative amounts o~ tXe first and second compositions are varied In each Example the components were blended in an extruder and the resulting polyblend was formed into samples which were then tested to determine the Izod impact strength, (ASTM D-256)~ (in some cases) the Falling Dart Impact Strength tFDI), (ASTM D-2444), and heat distortion temperature ~DTUL) under a load of 18.6 kg./sq.cm.
(ASTM-D 648), The components used in the examples were as follows:
~ ~-MS/AN - a copoIymer of ~-methylstyrene and acrylonitrile con-taining approximatel~ 28% AN and up to 10% of styrene, which is present as a separately prepared matrix polymer.
S/AN - a copolymer o~ styrene and acrylonitrile ln a 72:28 weight ratio, present as a separately prepared matrix polymer, 25 A~S-I - prepared by the graft suspension polymerization o~
acrylonitrile and styrene in a weight ratlo of 28:72 in the presence of polybutadiene, ABS-I contains 14% by weight of polybutadiene.
ABS-2 - prepared by the graft emulsion polymerization o~ acrylo-3o nitrile and styrene in a weight ratio of 30:70 in the 2~7;3 presence of polybutadiene. ABS-2 contains 40% by ~elght of polybutadiene.
S/MA-l - a copolymer o~ styrene and maleic anhydrlde in a weight ratio of about 75:25.
S/MA-2 - a copolymer of styrene and maleic anhydride in a Neight ratlo Or about 83:17.
RM-S~MA - a polymer formed by polymerizing styrene and maleic anhydrlde in a weight ratio of 76:24 in the presence Or 14.5~ by weight of a butadiene/styrene block copolymer rubber to give an SMA polymer grafted on to the rubber substrate and free SMA matrix polymer.
The results of testing blends of certain Or the above components are set out in Table 1 below. All parts are by weight unless otherwise specified. Examples marked (c) are for the sake of comparlson.
The Izod impact strengths were measured uslng 3.2 X 12.7 X 63.5 mm compression molded samples, notched 2.54 mm.
The DTUL figures glven are for 3.2 X 12.7 X 124 mm com-pression molded samples tested under a 18.6 kg./sq.cm. stress.
Examples 17 to 33 and 40-43 inolude 0.2% and 0.3% by weight respectively, of 2,6-ditertiarybutyl-4-methyl phenol (an antioxidant) and mangesium stearate (a lubricant).

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~ * * * * ~ ~ ~ . . ~ ~ O w )i * ~ C tl I_ 1~2~73 From a comparison of the groups of Examples 2 and 3,

4 and 5; 6~ 7 and 8; 9, lO, ll and 12, and l7, 18 and l9, it can clearly be seen that for a given amount of rubber in the polyblend the best impact propertles (Izod and F.D.I.) are obtained when the rubber is distributed betwean the ABS and the polymerlc aomposltions~
It can be seen from ~xamples 6, 7 and ~ that whlle the DTUL may vary substantially wlth the S/MA polymer used, the lmpact strength is very low unless the S/MA is rubber modified.
From 8 comparlson of Examples 17, 18 and l9 it can be seen that where there is no rubber contrlbutian ~rom the SMA there i8 a dramatic drop ln lmpaot strength.
I Fro~ Examples 9, lO and 11, it can be seen that replace-ment of the separately prepared ~~MS/AN matrix polymer associated wlth the ABS with S/AN or even S/MA has only a marginal ef~ect on the impact properties, Finally, it can be seen that an increase in the S/MA con-tent, whether rubber modified or not improves the DTUL and that this property is also lmproved by substitution of ~-MS/AN for S/AN
as the matrix polymer of the ABS component.
In addltion to the above polyblends it is found that blends o~ A3S with a rubber modi~ied polymeric composltion that com-prises the optional termonomer have advantageous physlcal properties.
~hese polyblends are now further descrlbed ln the follo~ing Examples.
, . , . ;

These F.xamples describe the production of rubber-modified polymers o~ styrene, maleic anhydride and methyl methacrylate and the properties of polyblends of such copolymers with ABS.
The process described bslow is that used in Example 20 but essentiallY the same process was used in all the other Examples with the difference that the initial monomer charge and the late added charge were changed in accordance with a computer model based on monomer reactivities to obtain polymPrs of ~irferent compositions. Typical late addition schedules of sp~clpied polymers predicted on the basis of the model ar~ shown in ~able II.
An agltated resin kettle was charged with 316 g. Or styrene, 22.6 g. of methylmethacrYlate, 0.5 ~. o~ brisnonylphe phosphate ~a stabilizer) and a solvent mixture consisting or 50 g. o~ methyl ethyl ketone (MEK) and 75 g- of toluene. In this mixture were dlssolved 44.2 g- o~ polybutadiene rubber.
A solution o~ o.6 g. o~ azoblsi90butyronitrile ~AIBN) in 30 mjl of MEK was prepared . 5 M1 o~ this solutlon was added to the solution in the resin kettle and the res~ was added at a rate o~ 3 mlfhour therea~ter.
The reaction mlxture was raised to 85C. and maintained at that le~el while late addition of a solution of 97 g. Or maleic anhydride and 25 g. o~ methyl methacrylate in 97 g. Or MEK
was begun. The late addition was continued over a 6-1/2 hour perlod, After additlon was oomplete the reactlon was held at the reaction temperature for a ~urther hour before 0.5 g. o~ hydro-quinone was added to short-st.op the reaction.
~ he polymer was then separated ~rom the solvent and residual monomer blended with any other desired polymeric com-ponents in an extruder and molded into samples for evaluation.

-` 3L~I~3 2~7 3 ~ABLE II
LATE MONOMER ADDITION SCHEDULE
T~rget Polymer Composition Initial Charge Late Addition (S/MA/MMA) _ (S/MAtMMA) 56.8/26,8il6,4 34,4/2.5/16.4 22.4/22,2/o 61.3~24 ~14,7 49.2/2.l~ .7 12.1/21.9fO
72 ~22 ~ 6 72 /1.5~ 5.1 o /20.5~0.9 30 ~35 ~35 o /35 /18.7 30 ~ o /16.3 65 ~25 /lo 60 /2.1/lo 5 ~22.9/o 70 /? /1o 70 /1.4/8.8 o /18.6/1.2 o 65 /15 /20 65 /1.3/19.2 o ~13.7~0.8 /30 /lo 40.6/2.5/lo lg.~/27.4/~
In each case the amounts glven are percentages by weight based on the total fir~al polymer weight.
The results obtained in Examples 20-29 are set rorth ln Table III below. Polymer a~ was obtalned usin~ a- 65~25~10 target polymer additlon schedule; polymers b) and c~ used the 56.8/26.8/16.4 ~chedule.

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~Z~73 08-12-037}A

The above results show that rubber-modified polymers o~
styrene, maleic anhydride and methyl methacrylate have very advanta-geous properties particularly when blended with ABS.

The following Examples demonstrate the production of rubber-modified polymers or styrene, maleic anhydride and acrylo-nitrile and their blends with ABS.
The processes used are essentially those described in Examples 20-29 except that a dirrerent late addition schedule is required. The appropriate schedules, derived as above, from a computer model and based on the monomer reactivities, are set forth in Table IVbelow.
TABLE IV
LATE MONOMER ADDITION SCHEDULE
In each case the amounts given ar0 percentages by weight based on the total final polymer weight.
Target Polymer Composition Initial Monomer Charge Late Monomer Charge S~MA/AN S~MA/AN ~ S~MA~AN
2063~25/12 63/3.3~10 0~21.7~2 60j30~10 (Used in Table ~I ) 60~4.7~18.7 0/25.3~1.3 65~20/15 65~2.6~13 1 0~1~.4~1.9 67/17~16 67/2.0/13.~6 9/15.D~2.4 In Table V below the components and proportions Or rubber-modified styrene~maleic anhydride~acrylonitrile polymer, (RM-S~MA/AN~, alone and in blends with ABS, are described. The properties of the resultant polyblends are also set forth in the same TabIe.
The results indicate clearly the utility Or RM-S~MA/AN
polymers in blends with ABS.

TABLE V
Examples Polymer Components 30 31 32 33 34 35 tParts by Weight) RM-S~MA/AN (68/26f6) 100 50 60 100 5060 (polybutadiene substrate) ABS-l 9.2 10 9.2 10 ABS-2 28.7 3 28.7 30

5 ~ -MSfAM . 12,1 . 12.1 Total Rubber (% by w-t.~ 14,3 19.95 21.9 14.3 19.95 21.9 Rubber from RM-S/MA/AN . 14 . 3 7 .15 8 . 5 14 . 3 7 .15 8 . 5 Irganox 1076 ~antloxidant) 0.5 0.5 0.5 0.5 0.5 0.5 Ma~nesium Stearate 0.3 0.3 0.3 0.3 0.3 0.3 ~lubricant~
10 ~erpinoline tChain 0.1 - - 0.1 - -transfer agent) . . .
Properties Izod impact stren~th J/m notch X 102 0.811.57 1.57 1.121.87 1.97 DTUL (C.) 136. 109 112 136 lOg 111 Note: Examples 30-32 were prepared using an RM-S/MA/AN polymer 15 that had been devolatilized in an oven.
ln Examples 33- 36the polymer was precipitated from n-hexane to separate it from unreacted monomer.

-Th~s series of Examples illustrate tha use o~ a different catalyst known to favor grafting in the production of rubber-modi~ied copolymers of styrene, maleic anhydrlde and methyl meth-acrylate.
The process described in Example 20 was following except that the catalyst was changed ~rom azobislsobutyronitrlle to a mixture o~ tertiary butyl peroctoate and tertiary butyl peracetate.
The results obtalned are set forth ln Table VI below. Example 43 is for the sake o~ comparison and shows the results obtained in the absence o~ the methyl methacrylate component. In this case the polymer used is RM-SMA.
~ABLE VI
Polymer Components Example_ (parts by weight~ 36 37 ~
15 RM-SJMA~MMA 67/26/7100 50 60 polymerlzed in presence of polybutadiene RM-SMA (76~24) - - - 100 ABS-I - 9.2 10 ABS-2 32.6 30 ~-MS/A~ - 8.2 .. . .
20 ~ Rubber from RM~S/MA/MMA 11.35 5 6.8 14.5*
from A~S - 14 5 13-4 Properties' Izod ImpaFt St~engtho.78 1~841.81 1.01 DTUL - C. 131 108 112119 25 *% rubber from RM-SMA.

31 ~C~ 73 Comparison Or ~xamples 20 to 22 with 36 to ~8, shows that uslng the peracid catalyst it is possible to ~et comparable impact strengths while using a smaller amount of total rubber.
Comparison of the RM-SMA with ~M-S/MA~MMA shows the advanta~e o~ having the MMA present.
- ~XAMPLE 40 This Example shows the advanta~es o~ RM-S~MA!~IA ter-polymers and their polyblends wlth ABS over the correspondlng RM-SMA
polymers and polyblends with ABS.
The compositlons compared were as follows:
RM-SMA - 76/24 - S/MA polymerized in the presence of 14.5% of a butadiene/styrene block copolymer.
RM~S/MA~MMA - 65/27/8 S/MA/MMA polymerized in the presence of 14.1% polybutadiene rubber.
RM-S~MA/MMA-ABS- 50/50 welght percent blend o~ ~I-S/MA/MMA with ABS total rubber content - 20% by wPight.
Tensile strength is measured by the method of ASTM D-638.
Compression molded samples were 3.2 X 12.7 X 127 mm thicknesssamples.
In~ection molded samples were 12.7 X 127 X 127.
Gloss was assessed by visual inspection and by rerlectance (photo-volts). The results are glven in Table VII ~below.
.

RM-S~MA~
~ RM S~MA~MMA RM-SMA~ABS MMA/ABS

--25 (ComP. molded) 117-121 130 106 109 (In;. molded) 125-127128-133 109 I12 Tensile 5trength at fail tInJ. 288.2 337.4 302~3 351.5 Molded) kg/sq.Gm.
G~oss dull rair - * good +Reflextance~ 10 * * ~ 7o * not evaluated.
from a sur~ace illuminated at a 60% angle using a photov~lt meter.

2~73 0û-12-0373A
. - 2~ -From ~he~e re0ult~ it oan be Be~n that distlnot ad~ ntA~
ln terms OI phy~ical prop~rties ar~ obtained by inoïuding me'chyl methacrylste ~ a term~nomer ~n torms of heat di~tort~on tempera-ture~ t~n8il~ 3bran~th and ~1083 Or the ~inal pro~uo~

q~heæe ~xample~ 111UBb~at~ bhe us~ of 8 polypentenamer"
tPP)~ a homopolymar o~ oyol~pen~Géne an~ ~ oopolymer oi` oyolop~n~asle, tCoPP~ ~ to r~plaoet the polybubadien~ u~d in bh~ pre~riou~ ~xample~ .
me oompc~itlon~ ~lesorlbe~ ln T~ble VI~ b~l~w were m~d2 up usin~.the rollowing po~ymer3.
PPM~ ~MA - A 7~/24 SMA polym~r polymerl~d in bhe pre~nae o~ ~ po~ypentenamQr u~ing a mlxtur~ oS ter'aiary butyl p~raoat~be an~ bertlarg bubgl peroa~oal;e a~ tha oatalyst/ln~tiator.
PPM-S/MA/MMA - A 66/2~/9 giMA/MMA polymeri~ed in the pre~r.oe o~ a polypentenan1er usln~ a mix~ure o~ ter~iarS
buby:l p~raaet~te and terbiary butyl perec~Goa~e ~ ~hQ o~b~lgsb/lnibi~bor.
5OPPM-S~MA -~ A 7~/24 ~MA eopolym~r polgmeri~ in bhQ pra~
~en~e o~ a eopol~mQr a~ ay~lopentQne with ~Ghylene ~abou:b 25%) u~ln~ a~ob~ bub~Yoni~rlia ~0 O~e~ Oe/~n~e~eO

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~ 2~73 _ 24 -As can be seen rrOm the above, the substitution o~ a cyclopentene homopolymer or copolymer for polybutadiene produces very comparable results indicating that the ef~ects shown do not depend on the use o~ polybutadiene.
~he above Ex~mPles are ~or the purposes Or iliustration only and are not lntended to represent any limitation in the scope of the lnvention. It is anticipated that many minor varia-tlons and modl~lcations in the lnvention dlsclosed hereln could be made wlthout departlng ~rbm the e~sence thereof and all such varlatlons and modificatlons are lncluded wlthin the purvlew Or thls lnvention.

Claims (18)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A polyblend comprising:
A. from 10 to 90% by weight of an ABS polymer having a rubber con-tent in the range of 5 to 70% by weight; and B. from 90 to 10% by weight of a polymeric composition comprising 1) a rubber substrate polymer having a glass transition tempera-ture below 0°C.; and 2) a superstrate polymer grafted onto the rubber substrate which comprises from 40 to 85% by weight of a monoalkenyl aromatic monomer and from 15 to 35% by weight of an un-saturated dicarboxylic acid anhydride, wherein the amount of the rubber substrate is in the range from 2 to 30% by weight of the polymeric composition, wherein the total amount of rubber in the polyblend is in the range of from 5 to 40% of the total weight of the polyblend, with the proviso that each of components A and B, contribute at least 5% of the total amount of rubber in the polyblend.

2. The polyblend of Claim 1 in which the superstrate polymer of component B further contains up to 30% by weight of a copolymerizable monomer.

3. The polyblend of Claim 2 in which the copolymerizable monomer is selected from the group consisting of C4 to C6 .alpha.-olefins, C1 to C3 alkyl esters of acrylic and methacrylic acids, acrylo-nitrile and methacrylonitrile.

4. The polyblend of Claim 1 wherein the ABS polymer com-ponent comprises from 75 to 25% and the polymeric composition correspondingly provides from 25 to 75% of the total polyblend weight.

5. The polyblend of Claim 1 in which the ABS polymer and the polymeric composition each provides at least 10% by weight of the total rubber content of the polyblend measured as ungrafted rubber.

6. The polyblend of Claim 1 in which the total rubber content of the polyblend, measured as ungrafted rubber, is from 10 to 30% by weight of the polyblend.

7. The polyblend of Claim 1 in which the ABS polymer comprises a matrix component that is a copolymer of .alpha.-methyl styrene and acrylonitrile.

8. The polyblend of Claim 1 in which the rubber com-prises from 5 to 25% of the weight of the polymeric composition (component B).

9. The polyblend of Claim 1 in which the unsaturated dicarboxylic acid anhydride is maleic anhydride.

10. The polyblend of Claim 1 in which the rubber sub-strate of component B is a copolymer of cyclopentene with a minor proportion of a non-cyclic .alpha.-olefin.

11. The polyblend of Claim 1 in which the polymeric composition consists of styrene and maleic anhydride grafted on to a butadiene rubber substrate in a weight ratio of 85:15 to 65:35.

12. A polyblend comprising:
A. from 10 to 90% by weight of an ABS polymer having a rubber con-tent in the range of 5 to 50% by weight; and B. from 90 to 10% by weight of a polymeric composition comprising 1) a rubber substrate polymer having a glass transition temperature below 0°C.; and 2) a superstrate polymer grafted onto the rubber substrate which comprises from 40 to 85% by weight of styrene and from 15 to 35% by weight of maleic anhydride, wherein the amount of the rubber substrate is in the range of from 2 to 30% by weight of the polymeric composition, wherein the total amount of rubber in the polyblend is in the range of from 5 to 40% of the total weight of the polyblend, with the proviso that each of components A and B, contribute at least 5% of the total amount of rubber in the polyblend.

13. The polyblend of Claim 12 in which the ABS polymer additionally contains a matrix polymer selected from copolymers of styrene or .alpha.-methylstyrene with acrylonitrile.

14. A polyblend comprising:
A. from 75 to 25% by weight of an ABS polymer comprising a rubber having a glass transition temperature below -30°C. grafted with acrylonitrile and styrene and/or .alpha.-methylstyrene, the grafted rubber being dispersed in a matrix polymer formed by copoly-merization of acrylonitrile and styrene and/or .alpha.-methylstyrene in which the rubber is present in an amount that is from 5 to 70% of the weight of the ABS polymer and in which the ratio of the weight of styrene and/or .alpha.-methylstyrene to the weight of acrylonitrile in the ABS polymer is from 60:40 to 80:20; and B. from 25 to 75% by weight of a polymeric composition comprising a diene rubber having a glass transition temperature below -30°C., grafted with a superstrate polymer and dispersed in a matrix polymer wherein the matrix copolymer and the superstrate copolymer taken together comprise from 40 to 85 parts by weight of styrene, from 15 to 35 parts by weight of maleic anhydride and from 0 to 30 parts by weight of a copolymerizable termonomer selected from the group consisting of isobutylene, methylmeth-acrylate and acrylonitrile and wherein the amount of rubber is from 5 to 25% by weight of the second composition;
the proportions and compositions of A and B being selected such that the total amount of rubber in the polyblend measured as un-grafted substrate is from 10 to 30% of the weight of the polyblend and such that each of A and B supplies at least 10% of the total weight of the rubber, measured as ungrafted substrate, in the poly-blend.

15. The polyblend of Claim 14 in which the ABS polymer provides from 60% to 90% of the total amount of rubber, measured as ungrafted substrate, in the polyblend.

16. The polyblend of Claim 14 in which the polymeric composition comprises from 2 to 10% by weight of isobutylene based on the combined weights of the matrix and superstrate polymers in the polymeric composition.

17. The polyblend of Claim 14 in which the polymeric composition comprises from 2 to 20% by weight of methyl meth-acrylate based on the combined weights of the matrix and super-strate polymers in the polymeric composition.

18. The polyblend of Claim 14 in which the polymeric composition comprises from 2 to 20% by weight of acrylonitrile based on the combined weights of the matrix and superstrate polymers in the polymeric composition.