Gels derived from extending grafted centipede polymers and polypropylene

The present invention teaches a method for enabling the formation of a high damping, soft polymer gel. The method includes: reacting a poly(alkenyl benzene-co-maleimide) polymer with a maleated polyalkylene and an alkyl diamine under substantially dry conditions sufficient to form a polyalkylene grafted poly(alkenyl benzene-co-maleimide) polymer product; and, dispersing the polyalkylene grafted poly(alkenyl benzene-co-maleimide) polymer product with an extender oil sufficient to form the gel. The present invention also contemplates a polymer gel composition, a polymer composition and an article manufactured from the polymer gel composition.

FIELD OF THE INVENTION
 This invention relates to the production of polyalkylene grafted
 poly(alkenyl benzene-co-maleimide) polymers and to the use of such
 polymers when oil extended in producing high damping, soft materials.
 BACKGROUND OF THE INVENTION
 The polymerization of styrene and maleic anhydride by free radical
 initiation is well known in the prior art. Similarly,
 poly(styrene-co-maleic anhydride) polymer is well known. Further,
 imidization between a maleic anhydride and a primary amine group is a
 commonly known chemical reaction. Patent publications which have
 recognized these reactions include: German Patent DE 4241538, assigned to
 Leuna-Werke A.-G; Japanese Patent JP 94248017, assigned to Monsanto Kasel
 Kk.; and, Italian Patent EP 322905 A2, assigned to Montedipe S.p.A.
 Various other non-patent publications have also recognized these
 reactions. Included among them are: L. E. Colleman, Jr., J. F. Bork, and
 H. Donn, Jr., J. Org. Chem., 24, 185(1959); A. Matsumoto, Y. Oki, and T.
 Otsu, Polymer J., 23 (3), 201(1991); L. Haeussler, U. Wienhold, V.
 Albricht, and S. Zschoche, Themochim. Acta, 277, 14(1966); W. Kim, and K.
 Seo, Macromol. Rapid Commun., 17, 835(1996); W. Lee, and G. Hwong, J.
 Appl. Polym. Sci., 59, 599(1996); and, I. Vermeesch and G. Groeninckx, J.
 Appl. Polym. Sci., 53, 1356(1994).
 The synthesis of monofunctional N-alkyl and N-aryl maleimides are also well
 known in the prior art. They have been extensively used to improve the
 heat stability of homo- and especially copolymers prepared from vinyl
 monomers. Typically, the bulk resins comprise ABS
 (poly(acrylonitrile-co-butadiene-co-styrene)) or a polyblend of
 poly(acrylonitrile-co-butadiene) and poly(styrene-co-acrylonitrile); PVC
 (poly(vinyl chloride)); SAN (poly(styrene-co-acrylonitrile)); PMMA
 (poly-(methyl methacrylate)); and the like. The maleimides can be
 copolymerized with other monomers such as acrylonitrile, butadiene,
 styrene, methyl methacrylate, vinyl chloride, vinyl acetate and many other
 comonomers. A more preferred practice in the industry is to produce
 copolymers of maleimides with other monomers such as styrene and
 optionally acrylonitrile and to blend these with ABS and SAN resins. In
 any event, the polymer compositions are adjusted so that the copolymers
 are fully compatible with the bulk resins (e.g., ABS and/or SAN) as shown
 by the presence of a single glass transition point (T(g)) as determined by
 differential scanning calorimetry (DSC).
 It has long been recognized that two or more polymers may be blended
 together to form a wide variety of random or structured morphologies to
 obtain products that potentially offer desirable combinations of
 characteristics. However, it may be difficult or even impossible in
 practice to achieve many potential combinations through simple blending
 because of some inherent and fundamental problem. Frequently, the two
 polymers are thermodynamically immiscible, which precludes generating a
 truly homogeneous product. This immiscibility may not be a problem since
 often it is desirable to have a two-phase structure. However, the
 situation at the interface between these two phases very often does lead
 to problems. The typical case is one of high interfacial tension and poor
 adhesion between the two phases. This interfacial tension contributes,
 along with high viscosities, to the inherent difficulty of imparting the
 desired degree of dispersion to random mixtures and to their subsequent
 lack of stability, giving rise to gross separation or stratification
 during later processing or use. Poor adhesion leads, in part, to the very
 weak and brittle mechanical behavior often observed in dispersed blends
 and may render some highly structured morphologies impossible.
 It is particularly desirable to prepare a grafted copolymer having the
 impact strength of polypropylene and the elastomeric properties of a block
 copolymer. It is also desireable to add an extender or plasticizer to the
 resultant grafted copolymer in order to obtain a copolymer having a low
 Shore A hardness.
 OBJECTS OF THE INVENTION
 Accordingly, it is an object of this invention to provide an oil or low
 molecular weight component extended grafted "centipede" polymer of a
 maleated polypropylene and a poly(alkenyl benzene-co-maleimide) that is
 useful in producing high damping and soft materials.
 More specifically, it is an object of this invention to provide a grafted
 centipede polymer formed by reacting maleated polypropylene and a
 poly(alkenyl benzene-co-maleimide) with a diamine.
 Another object of the invention is to provide oil or low molecular weight
 component extended grafted centipede polymers that exhibit improved
 properties, including low Shore A hardness less than 35, high damping
 properties and a service temperature of about 100.degree. C.
 SUMMARY OF THE INVENTION
 The present invention is directed to an oil or low molecular weight
 component extended grafted poly(alkenyl
 benzene-co-maleimide)-polypropylene polymer soft gel composition having
 damping properties useful in producing molded products having heat
 resistance and a high elasticity and damping property.
 The present invention is broadly directed to grafted polymer compositions
 of a maleated polypropylene and a poly(alkenyl benzene-co-maleimide)
 reacted with a diamine. It is further directed to a process for preparing
 an oil extended grafted polymer compositions broadly comprising a maleated
 polypropylene grafted to a functionalized thermoplastic material, namely a
 poly(alkenyl benzene-co-maleimide), under conditions sufficient to permit
 grafting of the functionalized polypropylene with the functionalized
 thermoplastic material. The grafted polymer is a glass-like material that
 becomes a soft and rubber-like elastomer after being oil-extended.
 DETAILED DESCRIPTION OF THE INVENTION
 The extended grafted polymer gels of the present invention contain: 100
 parts by weight of a grafted polymer of a poly(alkenyl
 benzene-co-maleimide) having at least one maleated polypropylene segments
 grafted thereto through the at least one functional linkage formed by a
 crosslinking reaction with a diamine grafting agent; and at least 30,
 preferably 30 to 1000, parts by weight of an extender such as an oil or a
 low molecular weight component.
 The poly(alkenyl benzene-co-maleimide) is a "centipede" polymer formed by
 imidizing a poly(alkenyl benzene-co-maleic anhydride) with a primary
 amine. The "centipede" polymer has a high molecular weight spine connected
 with many relatively short side chains formed from the addition of the
 primary amines. The length of the main chain usually equals or is longer
 than the entanglement length, which is herein defined theoretically as an
 order of magnitude of 100 repeating units, while the length of the side
 chains is much smaller than the entanglement length.
 The preferred alkenyl benzenes contributed monomer units of the
 poly(alkenyl benzene-co-maleimide) "centipede" polymer are either styrene
 or alpha-methylstyrene. The terms "alkenyl benzene" and "vinyl aromatic"
 are understood to be interchangeable as used herein.
 The poly(alkenyl benzene-co-maleimide) described herein are subsequently
 graft-reacted through a difunctional linking or grafting agent to a
 maleated polypropylene to yield a grafted polymer having at least one
 polypropylene segment grafted thereto through the at least one functional
 linkages thus formed.
 The maleated polypropylene may be any of the conventionally known
 polypropylene compounds that are subsequently maleated by methods known in
 the art. The polypropylene grafted segment or segments have molecular
 weights "M.sub.w " of about 10,000 up to about 10,000,000, or higher,
 preferably about 20,000 to about 300,000.
 The crystallinity, or tacticity, of the polypropylene may vary from being
 substantially amorphous to being completely crystalline, that is from
 about 10-100% crystallinity. Most typically, because of the extensive
 commercial use of isotactic polypropylene, the grafted polypropylene will
 be substantially crystalline, e.g., greater than about 90%. Generally, the
 polypropylene is substantially free of ethylene. However, under certain
 circumstances small amounts of ethylene, on the order of less than about
 10% by weight, may be incorporated. Furthermore, in certain instances the
 polypropylene contain small amounts of ethylene in copolymers known as
 "reactor copolymers". Thus, it is within the scope of the invention that
 the grafted polypropylene contain minor amounts of ethylene, both as part
 of ethylene-propylene segments and as polyethylene segments.
 Polymerization conditions for the preparation of polypropylene are well
 known in the art. Propylene can be polymerized into isotactic
 polypropylene in the presence of stereo-specific Ziegler-Natta catalyst
 systems comprising compounds of the transition metals of Groups 4 to 6 and
 8 of the Periodic Table of elements, preferably titanium compounds, most
 preferably titanium halides, and organometallic compounds of elements of
 groups 1 to 3 of the Periodic Table, especially aluminum alkyls or
 aluminum alkyl halides. Illustrative examples include titanium
 trichloride, titanium tetrachloride as catalysts and triethylaluminum and
 diethyl aluminum chloride as cocatalysts. These transition metal catalyst
 systems can be non-supported or supported, for example, silica gel, or
 metal oxides and dihalides, such as MgO, MgCl.sub.2, ZnCl.sub.2, etc. Such
 systems can be reacted together and can be complexed with a variety of
 Lewis-base electron donors.
 Molecular weight control is typically achieved by the incorporation of
 hydrogen via a feed stream into the polymerization reactor. The hydrogen
 is added at about 0 to 30 mole % based on the total monomer. The
 polymerization reaction is preferably conducted according to the slurry
 method employing an inert hydrocarbon diluent or liquid propylene as the
 vehicle. The polymerization temperature can be in the range of about
 50.degree. C. to about 100.degree. C. and is preferably at a range or
 about 60.degree. C. to about 80.degree. C. Polymerization pressure can
 also vary over a wide range and is not particularly limited. The
 polymerization pressure can for example be in the range from between
 atmospheric pressure to 37,000 KPa. Such procedures and components are
 only illustrative of the knowledge in the art with respect to
 polypropylene polymerization, any are contemplated as useful within the
 scope of the invention. For general review of literature and patents in
 the art see "Olefin Polymers (Polypropylene)" in the Kirk-Othmer
 Encyclopedia of Chemical Technology, 3rd Edition v. 16, 453-469 (J. Wiley
 & Sons, 1981).
 The maleinization of the polypropylene compound to maleated polypropylene
 is conveniently accomplished by heating a blend of polypropylene and
 ethylenically unsaturated carboxyl group-containing compounds, e.g.,
 maleic anhydride, within a range of about 150.degree. to 400.degree. C.,
 often in the presence of free-radical initiators such as organic peroxides
 that are well-known in the art. Free-radical grafting of the carboxyl
 group-containing compounds onto the polypropylene readily results. Methods
 of preparing these grafted polymers are well-known in the art as
 illustrated, inter alia, in U.S. Pat. Nos. 3,480,580, 3,481,910,
 3,577,365, 3,862,265, 4,506,056, and 3,414,551 the disclosures of which
 are incorporated herein by reference. Such processes are well-known in the
 art, for example, an independent source of the description of the process
 is found in Y. Minoura, M. Ueda, S. Mizinuma and M. Oba, J. Applied
 Polymer Sci. 1625 (1969). The use of heat and/or physical shearing
 optionally with the free-radical initiators, in such equipment as
 extruders, masticators, and the like, to simultaneously accomplish
 controlled degradation in molecular weight of the polypropylene along with
 the free-radical grafting of the maleic anhydride, as is known in the art,
 will be useful in accordance with this invention.
 In particular, it is preferable to conduct the maleinization with such
 amounts of maleic anhydride and free-radical initiators, and under
 conditions of temperature and shearing such that free-radical sites on the
 polypropylene are formed substantially at the time of scission of the
 polypropylene chains and are formed at the point of such scission. The
 maleic anhydride is then grafted onto the scissioned end of one side of
 such broken chains. In this manner the anhydride groups are located
 principally at the ends of the maleated polypropylene chains, and the
 substantial majority of such maleated polypropylene chains contain one
 site of maleinization. This procedure permits grafting of the maleated
 polypropylene at its maleated end to the maleated block copolymer though
 the use of a difunctional linking or grafting agents having two functional
 groups each functional group being reactive with a maleate group on the
 polypropylene and block copolymer. Multiple sites of maleinization can
 lead to grafting of the maleated polypropylene to more than one maleated
 block copolymer polymer chain or at more than one site of one or more
 maleated block copolymer. The same substantial chemistry applies to the
 centipede polymers of the present invention.
 In accordance with the above, the free-radical initiator is preferably used
 and will typically be utilized in an amount of from about 0.01 to 1.0 wt.
 %, preferably from about 0.02 to 0.5 wt. %, and most preferably from about
 0.04 to 0.3 wt. % of the total polypropylene, and solvent if used, and
 will be added first. The mixture is then heated to a temperature at or
 about the known decomposition temperature of the selected free-radical
 initiator, concurrently with any optional mechanical shearing. The maleic
 anhydride is subsequently added in an amount typically from about 0.01 to
 10.0 wt. %, preferably from about 0.1 to 5 wt. %, and most preferably
 about 0.75 to 2 wt. % of the total polypropylene.
 The maleated polypropylene of this invention contain from about 0.01 wt. %
 incorporated maleic anhydride, based upon the weight of the maleated
 polypropylene, up to about 5 wt. %. Preferably the maleic anhydride
 content will be from about 0.01 to about 2 wt. %, most preferably about
 0.03 to about 0.2 wt. %. As will be apparent, unreacted polypropylene will
 also be present in the reaction mix as will minor amounts of reaction
 by-products, such as decomposed free-radical initiator compounds and low
 molecular weight free-radical products. These by-products are
 substantially removed, by methods known in the art, e.g., sparging with
 nitrogen or washing with water. Maleic anhydride may not be left in
 substantial amounts in the polymer without detrimental affects on the
 subsequent reaction of the poly(maleimide-co-alkenyl benzene) with the
 maleated polypropylene.
 The poly(alkenyl benzene-co-maleimide) of the present invention is formed
 by reacting a poly[alkenylbenzene-(co)-(maleic anhydride)] at from about
 100.degree. C. to about 250.degree. C. and from about slightly above
 vacuum to about 20 atmospheres, under substantially dry conditions in the
 presence of a primary amine. The present invention is preferably directed
 to a polymer compositions of a poly(styrene-co-maleimide) formed by
 reacting a poly(styrene-co-maleic anhydride) with a primary amine.
 For the purposes of this invention, poly(alkenyl benzene-co-maleimide) and
 poly(alkyl benzene-co-maleic anhydride) are defined to encompass random
 and stereo-specific copolymers, including copolymers having alternating
 alkenyl benzene and maleimide or maleic anhydride contributed monomer
 units along the polymer backbone. Such alternating structure are typically
 described as poly(alkenyl benzene-alt-maleimide) and poly(alkyl
 benzene-alt-maleic anhydride); however, these polymers are encompassed
 herein within the descriptions poly(alkenyl benzene-co-maleimide) and
 poly(alkyl benzene-co-maleic anhydride).
 Processes for forming poly(alkyl benzene-co-maleic anhydride) polymers are
 well known to those skilled in the art. The preparation of the copolymers
 from electron donor monomers, such as styrene, and electron acceptor
 monomers, such as maleic anhydride, as a result of complexation of the
 electron acceptor monomers may be carried out in the absence as well as in
 the presence of an organic free radical initiator in bulk, or in an inert
 hydrocarbon or halogenated hydrocarbon solvent such as benzene, toluene,
 hexane, carbon tetrachloride, chloroform, etc. (N. G. Gaylord and H.
 Antropiusova, Journal of Polymer Science, Part B, 7, 145 (1969) and
 Macromolecules, 2, 442 (1969); A. Takahashi and N. G. Gaylord, Journal of
 Macromolecular Science (Chemistry), A4, 127 (1970).
 Poly(alkyl benzene-co-maleic anhydride) polymers are prepared by reacting
 monomers of alkenylbenzene with maleic anhydride. The preferred alkenyl
 benzene monomers used for forming the poly(alkyl benzene-co-maleic
 anhydride) polymer are styrene or .alpha.-methylstyrene. Suitable, but
 less preferred substitutes are: p-methylstyrene, 4-phenylstyrene,
 m-methylstyrene, o-methylstyrene, p-tert-butylstyrene, dimethylstyrene,
 and combinations thereof.
 The poly(alkyl benzene-co-maleic anhydride) for use in the present
 invention is a polymer containing from about 5 to 99 mole percent of
 maleic anhydride monomer with the remainder being alkyl benzene monomer.
 The preferred poly(alkyl benzene-co-maleic anhydride) contains from 20 to
 50 mole percent of maleic anhydride monomer. The most preferred poly(alkyl
 benzene-co-maleic anhydride) for use in the present invention is
 poly(styrene-co-maleic anhydride) containing 50 mole percent of maleic
 anhydride monomer and 50 mole percent of styrene monomer. The comonomers,
 maleic anhydride and alkenyl benzene, can be randomly or alternatingly
 distributed in the chain, however, it is preferred to have these
 comonomers alternating along the polymer backbone chain.
 The poly(alkenyl benzene-co-maleic anhydride) has a molecular weight range
 between about 1,000 and up to about 500,000 or higher, more typically
 between about 10,000 and 500,000, and even more typically between about
 150,000 and 450,000, where the molecular weight is weight-average
 ("M.sub.w ").
 The poly(alkenyl benzene-co-maleimide) of the present invention is formed
 by reacting a poly(alkyl benzene-co-maleic anhydride) in the presence of a
 mono-primary amine at a temperature from about 100.degree. C. to about
 300.degree. C. and at a pressure from about slightly above vacuum to about
 20 atmospheres, under substantially dry conditions. The reactants are
 preferably dry mixed in the absence of solvents in a suitable mixing
 apparatus such as a Brabender mixer. It is preferable to purge the mixer
 with nitrogen prior to the charging of the reactants. The primary amine
 may be added in a singular charge or in sequential partial charges into
 the mixer containing a charge of poly(alkyl benzene-co-maleic anhydride).
 Preferably the primary amine is charged in ratio between 0.8 to 1.0 of
 moles of amine per monomer contributed units of maleic anhydride in the
 poly(alkyl benzene-co-maleic anhydride).
 Suitable primary amine include but are not limited to: alkyl amines; alkyl
 benzyl amines; alkyl phenyl amines; alkoxybenzyl amines; alkyl
 aminobenzoates; alkoxy aniline; and other linear primary amines containing
 from 1 to 50 carbon atoms, preferably 6 to 30 carbon atoms, in the alkyl
 and alkoxy substituents in these primary amines. It is understood that the
 alkyl and alkoxy substituents on the above discussed primary amines can be
 linear or branched, preferably linear, and saturated or unsaturated,
 preferably saturated. Exemplary, but not exclusive of such amines are:
 hexylamine, octylamine, dodecylamine and the like.
 The poly(alkenyl benzene-co-maleimide), prior to grafting with maleated
 polypropylene, preferably has a molecular weight range between about 1,000
 and up to about 500,000 or higher, more typically between about 10,000 and
 500,000, and even more typically between about 150,000 and 450,000, where
 the molecular weight is weight-average ("M.sub.w ").
 The centipede polymer of the present invention may be prepared by any means
 well known in the art for combining such ingredients, such as blending,
 milling or internal batch mixing. A rapid and convenient method of
 preparation comprises heating a mixture of the components to a temperature
 of about 50.degree. C. to about 290.degree. C.
 The centipede polymers of this invention are preferably manufactured by
 mixing and dynamically heat-treating the components described above,
 namely, by melt-mixing. As for the mixing equipment, any conventional,
 generally known equipment such as an open-type mixing roll, closed-type
 Banbury mixer, closed type Brabender mixer, extruding machine, kneader,
 continuous mixer, etc., is acceptable. The closed-type Brabender mixer is
 preferable, and mixing in an inactive gas environment, such as nitrogen or
 carbon dioxide, is also preferable.
 Grafting of maleated polypropylene and poly(alkenyl benzene-co-maleimide)
 is performed by addition of a grafting agent such as a polyamine,
 preferably an organic diamine, to a blend of maleated polypropylene and
 poly(alkenyl benzene-co-maleimide) to partially cross-link the
 polypropylene to the poly(alkenyl benzene-co-maleimide) through the
 maleate functional groups.
 Suitable organic diamines or diamine mixtures containing two aliphatically
 or cycloaliphatically bound primary amino groups are used as grafting
 agents for the process according to the present invention. Such diamines
 include, for example, aliphatic or cycloaliphatic diamines corresponding
 to the following general formula: R.sub.1 (NH.sub.2).sub.2 wherein R.sub.1
 represents an aliphatic hydrocarbon group having from 2 to 20 carbon
 atoms, a cycloaliphatic hydrocarbon group having from 4 to 20 carbon
 atoms, or an aromatic hydrocarbon group having from 6 to 20 carbon atoms
 or R.sub.1 represents an N-heterocyclic ring having from 4 to 20 carbon
 atoms, e.g., ethylene diamine; 1,2- and 1,3- propylene diamine;
 1,4-diaminobutane; 2,2-dimethyl-1,3-diaminopropane; 1,6-diaminohexane;
 2,5-dimethyl-2,5-diaminohexane; 1,6-diamino-2,2,4-trimethyldiaminohexane;
 1,8-diaminooctane; 1,10-diaminodecane; 1,11-diaminoundecane;
 1,12-diaminododecane, 1-methyl-4-(aminoisopropyl)-cyclohexylamine;
 3-aminomethyl-3,5,5-trimethyl-cyclohexylamine;
 1,2-bis-(aminomethyl)-cyclobutane; 1,2-diamino-3,6-dimethylbenzene; 1,2-
 and 1,4-diaminocyclohexane; 1,2-; 1,4-; 1,5- and 1,8-diaminodecalin;
 1-methyl-4-aminoisopropyl-cyclohexylamine; 4,4'-diamino-dicyclohexyl;
 4,4'-diamino-dicyclohexyl methane; 2,2'-(bis-4-amino-cyclohexyl)-propane;
 3,3'-dimethyl-4,4'-diamino-dicyclohexyl methane;
 1,2-bis-(4-aminocyclohexyl)-ethane;
 3,3',5,5'-tetramethyl-bis-(4-aminocyclohexyl)-methane and -propane;
 1,4-bis-(2-aminoethyl)-benzene; benzidine; 4,4'-thiodianiline,
 3,3'-dimethoxybenzidine; 2,4-diaminotoluene, diaminoditolylsulfone;
 2,6-diaminopyridine; 4-methoxy-6-methyl-m-phenylenediamine;
 diaminodiphenyl ether; 4,4'-bis(o-toluidine); o-phenylenediamine;
 o-phenylenediamine, methylenebis(o-chloroaniline);
 bis(3,4-diaminophenyl)sulfone; diaminodiphenylsulfone;
 4-chloro-o-phenylenediamine; m-amino-benzylamine; m-phenylenediamine;
 4,4'-C.sub.1 -C.sub.6 -dianiline such as 4,4'-methylenedianiline;
 aniline-formaldehyde resin; and trimethylene glycol di-p-aminobenzoate.
 Mixtures of these diamines may also be used.
 Other suitable polyamines for use as grafting agents in the process
 according to the present invention include bis-(aminoalkyl)-amines,
 preferably those having a total of from 4 to 12 carbon atoms, e.g.,
 bis-(2-aminoethyl)-amine, bis-(3-aminopropyl)-amine,
 bis-(4-aminobutyl)-amine and bis-(6-aminohexyl)-amine, and isomeric
 mixtures of dipropylene triamine and dibutylene triamine. Hexamethylene
 diamine, tetramethylene diamine, and especially 1,12-diaminododecane are
 preferably used.
 Thus in the preferred embodiment the process for preparing the grafted
 polymer of this invention comprises the steps of:
 (A) combining a commercially available poly[alkenylbenzene-(co)-(maleic
 anhydride)] and a primary amine under substantially dry conditions
 sufficient to react substantially most of the acid anhydride moieties to
 form the poly(alkenyl benzene-co-maleimide); and,
 (B) mixing a commercially available maleated polypropylene with the mass of
 step (A) under substantially dry conditions of elevated temperature;
 (C) adding a diamine to the reaction mass of step (B), under a condition of
 agitation sufficient to form the grafted polymer of the present invention
 and cooling; and,
 (D) adding an extender oil to the final polymer of step (C) under
 conditions of agitation.
 In broadest terms the process for preparing the grafted polymer of this
 invention comprises combining the poly(alkenyl benzene-co-maleimide) with
 the maleated polypropylene and the grafting agent under conditions
 sufficient to permit grafting of at least a minor portion of the
 poly(alkenyl benzene-co-maleimide) onto the polypropylene. Thus the
 grafted centipede polymer composition of this invention will comprise the
 reaction product of the above described the poly(alkenyl
 benzene-co-maleimide) grafting agent and the maleated polypropylene. The
 grafting reaction is accomplished by contacting the grafting agent and the
 poly(alkenyl benzene-co-maleimide) with the maleated polypropylene
 whereupon interaction and cross linking take place. Apparently the primary
 amino groups of the grafting agent react to form covalent chemical bonds
 (imide bonds) with the maleic moieties of the maleated polypropylene and
 the poly(alkenyl benzene-co-maleimide). The polypropylene is thus grafted
 to the poly(alkenyl benzene-co-maleimide) through covalent chemical
 functional linkages.
 For best results, a proportion of approximately one-half molar equivalent
 of grafting agent per molar equivalent of maleic moiety can be employed
 due to the difunctionality of the grafting agent. The contacting can be
 accomplished by combining solutions of the polymeric reactants in suitable
 solvents, such as benzene, toluene, and other inert organic and inorganic
 solvents, in a suitable reaction vessel under substantially anhydrous
 conditions. Heating will accelerate the reaction and is generally
 preferred. More preferably commercially, the contacting can be
 accomplished by premixing pre-formed pellets of the neat functionalized
 polymers and adding the grafting agent and melt processing in a physical
 blender or mixer, such as a Brabender mixer or an extruder, at
 temperatures of from about ambient to about 350.degree. C., preferably
 about 75.degree. to about 300.degree. C., and most preferably 120.degree.
 C. to about 250.degree. C. It is important that essentially all moisture
 or water be removed by drying prior to contacting the polymer reactants in
 order to avoid hydrolysis reactions which will compete with the sought
 cross linking and reduce the yield of the grafted copolymer composition of
 this invention.
 The amounts of poly(alkenyl benzene-co-maleimide) and maleated
 polypropylene reacted into the grafted compositions of the invention may
 vary somewhat depending upon the properties desired in the finished
 composition. In general, the amounts of maleated polypropylene included in
 the grafted composition may range from about 1 to about 50 percent by
 weight based on total weight of composition. Preferred amounts of maleated
 polypropylene are from 1 to 30 percent by weight with a particularly
 preferred amount being from 10 to 25 percent by weight. The amounts of
 poly(alkenyl benzene-co-maleimide) centipede polymer included in the
 grafted composition may range from about 99 to about 50 percent by weight
 based on total weight of composition. Preferred amounts of the centipede
 polymer are from 99 to 70 percent by weight with a particularly preferred
 amount being from 90 to 75 percent by weight.
 The centipede polymer gels of the present invention have an extender added
 to the prepared grafted copolymers during final processing. Suitable
 extenders include extender oils and low molecular weight compounds or
 components. Suitable extender oils include those well known in the art
 such as naphthenic, aromatic and paraffinic petroleum oils and silicone
 oils.
 Examples of low molecular weight organic compounds or components useful as
 extenders in the compositions of the present invention are low molecular
 weight organic materials having a number-average molecular weight of less
 than 20,000, preferable less than 10,000, and most preferably less than
 5,000. Although there is no particular limitation to the material which
 may be employed, the following is a list of examples of appropriate
 materials:
 (1) Softening agents, namely aromatic naphthenic and paraffinic softening
 agents for rubbers or resins;
 (2) Plasticizers, namely plasticizers composed of esters including
 phthalic, mixed phthalic, aliphatic dibasic acid, glycol, fatty acid,
 phosphoric and stearic esters, epoxy plasticizers, other plasticizers for
 plastics, and phthalate, adipate, sebacate, phosphate, polyether and
 polyester plasticizers for NBR;
 (3) Tackifiers, namely coumarone resins, coumarone-indene resins, terpene
 phenol resins, petroleum hydrocarbons and rosin derivative;
 (4) Oligomers, namely crown ether, flourine-containing oligomers,
 polybutenes, xylene resins, chlorinated rubber, polyethylene wax,
 petroleum resins, rosin ester rubber, polyalkylene glycol diacrylate,
 liquid rubber (polybutadiene, styrene/butadiene rubber,
 butadiene-acrylonitrile rubber, polychloroprene, etc.), silicone
 oligomers, and poly-.alpha.-olefins;
 (5) Lubricants, namely hydrocarbon lubricants such as paraffin and wax,
 fatty acid lubricants such as higher fatty acid and hydroxy-fatty acid,
 fatty acid amide lubricants such as fatty acid amide and
 alkylene-bis-fatty acid amide, ester lubricants such as fatty acid-lower
 alcohol ester, fatty acid-polyhydric alcohol ester and fatty
 acid-polyglycol ester, alcoholic lubricants such as fatty alcohol,
 polyhydric alcohol, polyglycol and polyglycerol, metallic soaps, and mixed
 lubricants; and,
 (6) Petroleum hydrocarbons, namely synthetic terpene resins, aromatic
 hydrocarbon resins, aliphatic hydrocarbon resins, aliphatic cyclic
 hydrocarbon resins, aliphatic or alicyclic petroleum resins, aliphatic or
 aromatic petroleum resins, polymers of unsaturated hydrocarbons, and
 hydrogenated hydrocarbon resins.
 Other appropriate low-molecular weight organic materials include latexes,
 emulsions, liquid crystals, bituminous compositions, and phosphazenes. One
 or more of these materials may be used as extenders.
 In accordance with the present invention, the grafted polymer containing
 gel composition of the present invention may have added thereto at least
 about 1, preferably 30 to 1,000, parts by weight of extender per 100 parts
 by weight of the grafted copolymers. Most preferred amounts of added
 extender include from about 50 to about 500 parts of oil per 100 parts of
 grafted copolymer and ideally about 80 to about 300 parts of extender per
 100 parts of grafted copolymer. The weight percent ratio of the
 polyalkylene grafted poly(alkenyl benzene-co-maleimide) to the extender is
 from about 100:1 to about 1:100, preferably 5:1 to about 1:5 .
 The polymer gels produced according to the present invention generally have
 high damping properties having a tan .delta. in the range of about 0.1 to
 about 1.0, preferably higher than 0.3 over the temperature range of
 30.degree. C. to 100.degree. C., and a Shore A hardness ranging from 0 to
 about 50, preferably about 0 to about 30, most preferably about 5 to 20 at
 about 20.degree. C. to 25.degree. C. or at room temperature. The service
 temperature of the gels of the present invention is less than or equal to
 100.degree. C. for most of the polymers of the present invention, e.g.,
 100.degree. C. compression set of the gel is about 50. Some of the
 extended polymers of the present invention have a potential use up to
 140.degree. C.
 It is frequently desirable to include other additives well known in the
 rubber art to the compositions of the present application. Stabilizers,
 antioxidants, conventional fillers, reinforcing agents, reinforcing
 resins, pigments, fragrances and the like are examples of some such
 additives. Specific examples of useful antioxidants and stabilizers
 include 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, nickel
 dibutyldithiocarbamate, zinc dibutyl dithiocarbamate, tris(nonylphenyl)
 phosphite, 2,6-di-t-butyl-4-methylphenol and the like. Exemplary
 conventional fillers and pigments include silica, carbon black, titanium
 dioxide, iron oxide and the like. These compounding ingredients are
 incorporated in suitable amounts depending upon the contemplated use of
 the product, preferably in the range of 1 to 350 parts of additives or
 compounding ingredients per 100 parts of grafted copolymer.
 A reinforcement may be defined as the material that is added to a resinous
 matrix to improve the strength of the polymer. Most of these reinforcing
 materials are inorganic or organic products of high molecular weight.
 Various examples include glass fibers, asbestos, boron fibers, carbon and
 graphite fibers, whiskers, quartz and silica fibers, ceramic fibers, metal
 fibers, natural organic fibers, and synthetic organic fibers. Other
 elastomers and resins are also useful to enhance specific properties like
 damping properties, adhesion and processability. Examples of other
 elastomers and resins include adhesive-like products including Reostomer
 (produced by Riken-Vinyl Inc.), hydrogenated polystyrene-(medium or high
 3,4) polyisoprene-polystyrene block copolymers such as Hybler (produced by
 Kurare Inc.), polynorbornenes such as Norsorex (produced by Nippon Zeon
 Inc.) and the like. In this case the foregoing materials are equally
 applicable to the present centipede polymer compositions.
 The gels containing oil or low molecular weight component extended and
 polypropylene compositions of the present invention may be prepared by any
 means well known in the art for combining such ingredients, such as
 solution blending, milling, internal batch mixing, or continuous extrusion
 of a solid form of the centipede polymer and polypropylene compositions
 and the other ingredients. A rapid and convenient method of preparation
 comprises heating a mixture of the components to a temperature of about
 50.degree. C. to about 290.degree. C.
 The gels containing oil extended grafted poly(alkenyl
 benzene-co-maleimide)-polypropylene compositions of the present invention
 can be manufactured by mixing and dynamically heat-treating the components
 described above, namely, by melt-mixing. As for the mixing equipment, any
 conventional, generally known equipment such as an open-type mixing roll,
 closed-type Banbury mixer, extruding machine, kneader, continuous mixer,
 etc., is acceptable. The closed-type is preferable, and mixing in an
 inactive gas environment, such as nitrogen or argon, is also preferable.
 The composition obtained using the manufacturing method of this invention
 can be molded with equipment conventionally used for molding
 thermoplastics. It is suitable for extrusion molding, calendar molding,
 and particularly injection molding.
 The composition of the present invention can be mixed in any conventional
 mixer such as a Banbury mixer or roll mill or extruder normally conducted
 within the temperature range of about 120.degree. C. to about 300.degree.
 C., preferably maintaining the composition above its melting point for a
 few minutes up to several hours, preferably 10 to 40 minutes. A
 particularly useful technique is to add any fillers in the beginning of
 the mixing cycle in order to take maximum advantage of heating time and to
 prevent surface bleeding and overheating when forming the molded articles.
 The resultant gel composition may be molded in appropriate press ovens and
 the like to form products in the form of extruded pellets, cut dices,
 preferably as small as possible since smaller pellets provide short
 heating times and better flow when utilized in flow molding. Ground
 pellets may also be utilized.
 The extended grafted centipede polymers of the present invention can be
 used in high temperature applications including uses in injection molding
 or in any other compositions typically used for elastomeric properties.
 In summary, the molded polymers produced from the gels containing extended
 grafted poly(alkenyl benzene-co-maleimide) and polypropylene compositions
 of the present invention retain elastomeric characteristics and are useful
 in high temperature applications and/or high damping applications.
 Damping is the absorption of mechanical energy by a material in contact
 with the source of that energy. It is desirable to damp or mitigate the
 transmission of mechanical energy from, e.g., a motor, engine, or power
 source, to its surroundings. Elastomeric materials are often used for this
 purpose. It is desirable that such materials be highly effective in
 converting this mechanical energy into heat rather than transmitting it to
 the surroundings. It is further desirable that this damping or conversion
 is effective over a wide range of temperatures and frequencies commonly
 found near motors, automobiles, trucks, trains, planes, and the like.
 A convenient measurement of damping is the determination of a parameter
 called tan .delta.. A forced oscillation is applied to a material at
 frequency f and the transmitted force and phase shift are measured. The
 phase shift angle delta is recorded. The value of tan .delta. is
 proportional to the ratio of (energy dissipated)/(energy stored). The
 measurement can be made by any of several commercial testing devices, and
 may be made by a sweep of frequencies at a fixed temperature, then
 repeating that sweep at several other temperatures, followed by the
 development of a master curve of tan .delta. vs. frequency by curve
 alignment. An alternate method is to measure tan .delta. at constant
 frequency (such as at 10 hz) over a temperature range. We have defined a
 thermoplastic unfilled material as useful for damping when tan
 .delta.&gt;.about.0.3 over at least a 4 decade range, preferably a 6 decade
 range of frequency.
 It is further important that this high degree of absorption of energy be
 accompanied by good mechanical and thermal stability, as the part prepared
 from the subject polymers will be cycled through various environments and
 repeatedly such to various forces of compression, tension, bending, and
 the like.
 The compositions of the present invention are favorably used in the
 manufacturing of any product in which the following properties are
 advantageous: a high degree of softness, heat resistance, decent
 mechanical properties, elasticity and/or high damping. The compositions of
 the present invention can be used in all industry fields, in particular,
 in the fabrication of automotive parts, tire tread rubbers, household
 electrical appliances, industrial machinery, precision instruments,
 transport machinery, constructions, engineering, and medical instruments.
 Representative examples of the use of the extended graft polymers of the
 present invention are in the fabrication of damping materials and
 vibration restraining materials. These uses involve connecting materials
 such as sealing materials, packing, gaskets and grommets, supporting
 materials such as mounts, holders and insulators, and cushion materials
 such as stoppers, cushions, and bumpers. These materials are also used in
 equipment producing vibration or noise and household electrical
 appliances, such as in air-conditioners, laundry machines, refrigerators,
 electric fans, vacuums, driers, printers and ventilator fans. Further,
 these materials are also suitable for impact absorbing materials in audio
 equipment and electronic or electrical equipment, sporting goods and
 shoes. Further, as super low hardness rubbers, these materials are
 applicable for use in appliances, damping rubbers, and as low hardness
 plastics, and it is preferable for molding materials. Further, because the
 present compositions can be used to control the release of internal low
 molecular weight materials out from the compositions, it is useful as a
 release support to emit materials such as fragrance materials, medical
 materials and other functional materials. The compositions of the present
 invention also possess utility in applications of use in liquid crystals,
 adhesive materials and coating materials.
 Specific examples of uses of the compositions of the present invention as
 damping materials are as follows:
 in audio equipment, such as in insulators for a portable CD or a CD mounted
 on a vehicle, mike holders for home video cassette recorder, radio
 cassette recorder, karaoke or handy mike, etc., an edge cone of a speaker,
 a tape holder of a radio cassette, a holder of a portable mini-disk
 player, an optical disk holder of a digital video disk, etc.;
 in information relating equipment, such as in insulators for a hard disk,
 insulators for motors such as a spindle motor for HHD and stepping motor,
 insulators for floppy disk drive, insulators for CD-ROM of personal
 computer, and a holder for optical disk;
 in communication equipment, such as in a holder for compact high
 performance mike or speaker of a portable telephone, a pocket bell or PHS,
 a mike holder for a wireless equipment, and a disk holder for portable
 note type electronic equipment;
 in home electronics equipment, such as in insulators for CD-ROM of home TV
 game, insulators for cassette holder or CD-ROM of cassette holder or game
 machine, a holder of high performance mike, and cone edge of speaker; and
 in other applications, such as in damping materials for printer head of a
 wordprocessor, printer of personal computer, small or middle handy type
 printer, or name printers, and insulators for CD-ROM used for measure
 equipment.

In the following, the present invention will be described in more detail
 with reference to non-limitative examples. The following examples and
 tables are presented for purposes of illustration only and are not to be
 construed in a limiting sense.
 EXAMPLE 1
 Preparation of the Centipede Polymer
 A nitrogen purged Brabender mixer (.about.310 gram capacity) equipped with
 a Banbury blade was initially set to 30 rpm and the temperature was set to
 80.degree. C. The mixer was then charged with 150 g of
 poly(styrene-alt-maleic anhydride) (obtained from Aldrich Chemical Company
 of 1001 West Saint Paul Avenue, Milwaukee, Wis. Catalog Number: 18,293-1,
 CAS Number: 9011-13-6)(M.sub.n =350,000) and 96 g of octylamine (obtained
 from Aldrich, 99% purity). After 15 minutes of continuous mixing, the
 mixture was allowed to heat up at a rate of .about.4.degree. C./min. Once
 the temperature reached 150.degree. C., agitation was discontinued. When
 the temperature reached 210.degree. C., the heating element was set at
 isothermal conditions and agitation was again resumed at a speed of 70 rpm
 and mixing was continued for an additional 60 minutes. The heating element
 of the mixer was turned off, and the polymer mass within the mixer was
 permitted to cool down to 160.degree. C. at a rate of .about.4.degree.
 C./min. The agitation was then stopped and the centipede polymer product
 mass was then removed from the mixer.
 IR absorption peaks characteristic of the polymer mass were noted at 705
 cm.sup.-1, 1701 cm.sup.-1, 1770 cm.sup.-1, 2855 cm.sup.-1 and 2926
 cm.sup.-1. The ratio of the intensities was observed at I.sub.2926 to
 I.sub.1701.congruent.0.55. T.sub.g was estimated to be at 50.degree. C.
 The acid value of the polymer was 0.180 meq./gram using the NaOH titration
 method in a tetrahydrofuran solution.
 EXAMPLE 2
 Grafting of the Centipede Polymer and Maleated Polypropylene
 A nitrogen purged Brabender mixer (.about.310 g capacity) equipped with a
 Banbury blade was initially set to 60 rpm and 195.degree. C. The mixer was
 then charged with 36.6 g of commercial maleated polypropylene (from the
 Exxon Chemical Company, trade name Exxelor PO 1015). After 6 minutes, a
 charge of 145 g of the centipede polymer product of Example 1 was added to
 the mixer. The polymers were agitated for an additional 10 minutes. A
 charge of 1.6 g of dodecane diamine (from Aldrich, purity=98%) was then
 added, and at the same time the agitation speed was readjusted to 120 rpm.
 After 6 minutes the torque of the mixer increased and the agitation speed
 was again readjusted to 60 rpm. After an addition mixing at 60 rpm for 8
 minutes, the heating element of the mixer was turned off and the agitation
 speed was again readjusted to 40 rpm. The mixture was permitted to cool to
 about 160.degree. C. at a rate of .about.4.degree. C./min. Finally,
 agitation was discontinued and the grafted polymer product was removed
 from the mixer.
 EXAMPLE 3
 A charge of 15 g of the grafted polymer product of Example 2 was added to a
 Brabender mixer (50 g capacity) equipped with a roller blade. The mixer
 was initially set to 50.degree. C. and 20 rpm. A charge of 17.7 g of
 di(tridecyl)phthalate (DTDP) oil was slowly added to the contents of the
 mixer. After 5 minutes, the temperature of the mixer was reset to
 160.degree. C. and the agitation speed was reset to 70 rpm. After 105
 minutes of continuous mixing, another charge of 17.8 g of DTDP oil was
 added to the contents of the mixer. The material was then further mixed
 for 35 minutes at 90 rpm. The agitation was then discontinued and the
 product was removed from the mixer.
 EXAMPLE 4
 A charge of 15 g of the grafted polymer product of Example 2 was added to a
 Brabender mixer (50 g capacity) equipped with a roller blade. The mixer
 was initially set to 80.degree. C. and 20 rpm. A charge of 17.7 g of DTDP
 oil was slowly added to the contents of the mixer. After 8 minutes, the
 temperature of the mixer was reset to 160.degree. C. amd the agitation
 speed was reset to 90 rpm. After 12 minutes an additional two grams of the
 grafted polymer product of Example 2 was added to the contents of the
 mixer. After 108 minutes of continuous mixing, a charge of 17.8 g of
 trioctyl phosphate (TOP) oil was added to the contents of the mixer. The
 material was then further mixed for 195 minutes at 90 rpm. The agitation
 was then discontinued and the product was removed from the mixer.
 The products were thereafter molded into sheets and cylinder buttons at
 .about.155.degree. C. Ring samples were cut from these sheet for tensile
 measurements. The details of their physical properties are listed in the
 following Table 1:
 TABLE 1
 PP/
 Shore A
 Example Polymer Oil Type Centipede-C.sub.8 C.S..sup.1 Tb/Eb
 Tan .delta. hardness
 No. used (weight %) (wt. ratio) (100.degree. C.) (psi/%)
 (-10, 20, 45.degree. C.) (25.degree. C.)
 3 Example 2 DTDP 20/80 87.8 -- 0.78, 0.60,
 0.58 0-2
 (70%)
 4 Example 2 DTDP-TOP 20/80 65.4 21/193 0.54, 0.51,
 0.45 0-2
 (67%)
 .sup.1 The Compression Set (C.S.) was measured based on conditions of ASTM
 D395-89, except that the sample size and displacement were changed as
 follows: Sample height - 0.5 inches; Sample diameter - 0.55 inches;
 Displacement - Sample is compressed to 0.375 inches and stored in an oven
 at 100.degree. C. (or at 150.degree. C. in subsequent examples) for 22
 hours. The sample is removed from the oven, the stress on the sample is
 relieved, the sample is stored at room temperature for
 # 30 minutes and the recovery of the sample is measured as the final sample
 height as X in:
 Compression Set = ((0.5 - X)/(0.5 - 0.375)) .times. 100%.