Abstract: The present invention provides a method which makes it possible to manufacture substantially spherical resin granules with a narrow grain size distribution by a simple operation. According to the present invention, there is provided a method of manufacturing resin granules with a grain diameter of 1.about.100 .mu.m and narrow grain size distribution by controlling the cloud point of polyvinyl alcohol and other water soluble polymers.

Abstract: A stable aqueous emulsion comprising:(1) between about 20 and about 50% weight percent synthetic polymer solids, said solids comprising a copolymer or a terpolymer derived from:(a) between about 60 and about 90 mole percent of a vinyl ester, optionally including vinyl alcohol derived from said vinyl ester;(b) between about 10 and about 40 mole percent of one or more water soluble monomers; and(c) between about 0 and about 10 mole percent of an alkyl acrylate or alkyl methacrylate wherein alkyl represents an alkyl group containing between 1 and 20 carbon atoms;(2) between about 0.5 and about 5.0 weight percent of one or more surfactants or protective colloids; and(3) the balance water;wherein said aqueous emulsion has a viscosity of less than 1000 cps at 25.degree. C. and wherein said emulsion can provide adhesive properties and a process for producing the emulsion is provided. The emulsion is particularly suited for use as a wallpaper prepaste adhesive.

Abstract: Polyvinyl chloride-acrylate copolymers are plasticized with plasticizers to produce a composition having low hardness values. For example, Shore A values of 55 or less can be readily achieved. Such low values are often achieved by utilizing low amounts, for example less than 100 parts by weight, of the plasticizer for every 100 parts by weight of the PVC-acrylate copolymer. Low Shore A hardness values are also aided by the use of high amounts of acrylate units in the copolymer, that is amounts of at least 45 percent by weight based upon the total weight of the copolymer. The copolymer is made from a vinyl constituent which is a vinyl chloride monomer with an optional vinyl component comonomer and one or more acrylate monomers having the formula ##STR1## wherein R.sup.1 is an aliphatic, an aromatic, or combinations thereof, having from 1 to 18 carbon atoms, or a halogen derivative thereof, or hydrogen, and R.sup.

Abstract: Polyacetals useful as reduced-phosphate or phosphate-free detergent and cleaner additives are obtainable by cationically initiated polyaddition of(a) divinyl ethers and(b) dihydroxy compounds and also, optionally,(c) monohydroxy compoundsand have K values of from 8 to 100.

Abstract: Multifunctional viscosity index improvers for lubricating oils containing an EPM or EPDM polymer with pendant thiazoline units.

Abstract: Graft copolymers comprising a poly-alpha-olefin base polymer selected from the group consisting of polyethylene, polypropylene, polystyrene, and compatible mixtures thereof, having grafted thereto an olefinic monomer. The grafted monomer is present in an amount effective to increase the amount of protein that will bind to the graft copolymer as compared with the base polymer.Also disclosed are polymer/protein compositions comprising a graft copolymer having a protein immobilized on the surface thereof, processes for the preparation of the above-described graft copolymers and compositions, methods of immobilizing proteins, and methods of immunoassay based on such immobilization.

Abstract: Resin compositions of improved dispersibility and mechanical properties are obtained by polymerizing a polymerizable compound (A), insitu in a melted thermoplastic resin (B), in the presence of a dispersant (C) reactive or compatible with at least one of the resin (B) and polymerizate of (A).Suitable dispersants include those represented by the general formula (1) or (2)R.sub.1 --L(X--M--X--L).sub.n X--M--R.sub.2 (1)R.sub.1 --L(X--M--X--L).sub.n --R.sub.2 (2)wherein R.sub.1 and R.sub.2 are groups, such as hydrocarbyl acyl, alkoxy, hydroxyl, mercapto, amino, epoxy, isocyanate, carboxylic, carboxylic anhydride, carboxylic halide and aldehyde groups; L and M are residues of a polymer having a number average molecular weight of about 500-about 3,000,000, the difference in solubility parameter between the residue L or M and the resin (B) or polymerizate of (A) being not more than 0.

Abstract: A tire treadstock elastomer having reduced hysteresis is prepared by (1) preparing a living polymer by anionic polymerization of a conjugated diene or copolymerization of a conjugated diene with a monovinyl aromatic hydrocarbon, (2) endcapping the living polymer with at least one equivalent, preferably 3 to 15 equivalents, of a 1-vinylimidazole or 1-vinylbenzimidazole, preferably 1-vinylimidazole; (3) quenching and recovering the endcapped polymer and (4) curing the endcapped polymer using a conventional rubber curing recipe to form an elastomer having reduced hysteresis. This elastomer either alone or blended with a conventional treadstock rubber may form a tire treadstock.

Abstract: A method for preparing a graft copolymer is here disclosed which is characterized by comprising the step of carrying out a living polymerization of at least one (meth)acrylic ester by the use of a polymeric compound as an initiator having one or more units represented by the following formula (I) in a molecular chain substantially in the absence of water in the presence of a Lewis acid or a donor compound of an anion selected from the group consisting of HF.sub.2.sup.-, (CH.sub.3).sub.3 SiF.sub.2.sup.- and F.sup.- : ##STR1## wherein R is hydrogen or an alkyl group having 1 to 6 carbon atoms, and R' is an alkyl group having 1 to 12 carbon atoms.

Abstract: There are disclosed a process for producing a vinyl ester polymer having a high degree of polymerization at a high efficiency, which process comprises subjecting a vinyl ester monomer to seed polymerization by the use of a vinyl ester polymer emulsion as a seed emulsion under the conditions in which the charge of a water-soluble initiator per unit volume (1 liter) of reactant liquid charge is 1.times.10.sup.-8 to 2.times.10.sup.-4 mol, and the charge of the water-soluble initiator per one particle of the vinyl ester polymer particles in the seed emulsion is 1.times.10.sup.-28 to 1.times.10.sup.-20 mol, and a process for producing a vinyl alcohol polymer at a high efficiency from the vinyl ester polymer thus obtained.According to these processes of the present invention, both a vinyl ester polymer and vinyl alcohol polymer each having a higher degree of polymerization can be produced with ease on an industrial scale.

Abstract: A toner for developing electrostatic images contains a binder resin and a colorant or a magnetic material. The binder is prepared by polymerizing ethylenically unsaturated monomer(s) in the presence of less than 0.1% by weight of the monomer(s) of a radical polymerization initiator. The resulting polymer or copolymer is dissolved in a polymerizable monomer and solution or suspension polymerized with a radical polymerization initiator. The resulting binder resin is substantially free of fragments of radical polymerization initiator which tend to bond to molecular chain terminals.

Abstract: An improved process for the preparation of segmented copolymers of polyolefins and poly(methacrylates) is disclosed.

Abstract: Disclosed are substantially non-crosslinked anhydride-modified, saturated ethylene polymers and a process for making them which comprises mixing together in the absence of solvent:(a) maleic anhydride;(b) a free radical initiator;(c) a saturated ethylene polymer; and(d) a polyamideat a temperature at which the saturated ethylene polymer and polyamide undergo deformation and are converted to a molten or fluid state.

Abstract: Free radical-curable halogenated polyethylene polymer compositions, which are crosslinked with the aid of a crosslinking monomer selected from the group consisting of calcium diacrylate and calcium dimethacylate coagents and, optionally an alkyl aminoalkyl phenol vulcanization inhibitor, are provided. The compositions of the invention yield cured rubber articles with markedly improved tensile strength and scorch resistance. Processes for producing a cured rubber article from the disclosed free radical-curable elastomeric compositions and cured compositions prepared from such curable compositions are also provided.

Abstract: The invention concerns a process for the preparation of monodispersed polymer beads, wherein in a first stage a seed polymer is prepared in an organic solvent and in the presence of an R--X compound, separated and in a second stage an emulsion polymerization is carried out in an aqueous medium in the presence of the seed polymer. The polymer beads obtained in this manner have diameters in the range of 0.5 to 50 .mu.m, and may be used in the immobilization of proteins and cells, as carriers of catalysts and in peptide synthesis and in chromatography.

Abstract: An isobutylene polymer having an unsaturated group and comprising more than one unit per molecule on the average of the formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and each a hydrogen atom or a C.sub.1 -C.sub.8 alkyl group, R' and R" are the same or different and each a hydrogen atom, a methyl group or an ethyl group, and Q is a C.sub.1 -C.sub.30 divalent organic group, which provides a cured material having improved weather resistance.

Abstract: An elastomeric polymer composition that exhibits improved processability and green strength comprises: from about 95 to about 70 parts by weight of one rubbery polymer selected from the group consisting of butyl rubber, chlorinated butyl rubber and brominated butyl rubber and from about 5 to about 30 parts by weight of a block copolymer having an elastomeric polyisobutylene midblock and two plastomeric endblocks of polymerized monovinylidene aromatic monomers and star-shaped block copolymers having from three to six arms wherein the inner elastomeric blocks are polyisobutylene and the outer plastomeric blocs are polymerized monovinylidene aromatic monmers for a total of 100 parts by weight of the rubbery polymer and the block copolymer. Vulcanizates of the composition that exhibit reduced permeability to gases and improved tear strength are provided together with a process for their production.

Abstract: Compositions including polymers, copolymers and blends of stabilized stereoregular polymers of branched higher alpha-olefins, grafting compounds, free radical generators, glass and amino-functional silanes are provided as well as methods for making these compounds and articles thereof. These may also contain polyurethane film formers.

Abstract: Butadiene is polymerized alone or with a monomer such as styrene in a dispersion in propane, butane or its mixtures with minor amounts of other C.sub.4 -C.sub.6 alkanes, e.g., n-pentane and a dispersant which is preferably a hydrogenated styrene/ conjugated diene block copolymer to achieve stable dispersions at higher solids and butadiene levels possible with similar alkane dispersants.

Abstract: An improved process for the preparation of .alpha.-methylstyrene polymers by aqueous emulsion polymerization in which a styrene monomer mixture is first polymerized in a quantity of from 0.5 to 8% by weight of the total quantity of monomers and thereafter an .alpha.-methylstyrene monomer mixture is polymerized batchwise or semi-continuously.

Abstract: A process for grafting halogenated butyl rubbers with polymers based on conjugated diolefin monomers is provided which comprises mixing a first solution of halogenated butyl rubber with a second solution of a living alkali metal terminated polymer based on conjugated diolefin monomers and having a number average molecular weight of at least 40,000 at a temperature of from about -10.degree. C. to about 80.degree. C. for a period of time of from about 30 minutes to about 24 hours whereby the graft copolymer is formed. Rubber compositions comprising the halogenated butyl rubber graft copolymers upon vulcanization exhibit improved abrasion resistance and wet skid resistance while a desirable balance of other physical properties is maintained.

Abstract: Polypropylene impact copolymer compositions demonstrate not only good low temperature properties, including impact strength, but also resistance to stress whitening when the numerical ratio of the intrinsic viscosity of the copolymer phase to the intrinsic viscosity of the homopolymer phase is near unity and ethylene contents of the copolymer phase are in the range of 38% to 60% by weight. The impact copolymer compositions are useful in the production of molded and extruded articles, shaped containers, and films having good clarity.

Abstract: An improved process for the preparation of segmented copolymers of polyolefins and poly(methacrylates) is disclosed.

Abstract: Disclosed is a process for preparing an isobutylene-type allyl-terminated polymer, the process comprising mixing:(A) a cationically polymerizable isobutylene-containing monomer;(B) an organic compound serving as an initiator and concurrently as a chain transfer agent, the organic compound being represented by the formula (I) ##STR1## (C) at least one Lewis acid selected from the group consisting of (C.sub.2 H.sub.5).sub.2 AlCl, (C.sub.2 H.sub.5)AlCl.sub.2, SnCl.sub.4 and TiCl.sub.4 ; and(D) a compound serving as an end capping agent, the compound being represented by the formula (II) ##STR2## whereby the cationically polymerizable monomer is polymerized.

Abstract: Oil-absorbent compositions are disclosed. The compositions are crosslinked interpolymers of an alkylated styrene and a rubber. The compositions of the invention have high absorption capacities and absorption rates compared with prior-art compositions.

Abstract: A fluorine-containing elastomer composition comprising a specific fluorine-containing elastomer having iodine bonded thereto and having a multimodel molecular weight distribution, a specific vulcanizing agent, an organic peroxide, and a polyfunctional unsaturated compound. The fluorine-containing elastomer composition has not only excellent processability, mold release properties and burr-removal performance in molding but also capability of providing a vulcanization product which is not only improved with respect to mechanical properties, but also has extremely excellent resistance to chemicals and solvents, particularly methanol, and good metal-adhesion properties.

Abstract: Novel styrene derivatives are disclosed of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each represents a saturated aliphatic hydrocarbon group or an aromatic hydrocarbon group, and R.sub.3 is --OH, Cl, or a group of the formula --OR.sub.4 or ##STR2## wherein R.sub.4 represents a saturated aliphatic hydrocarbon group or an aromatic hydrocarbon groups. The functionalized styrene monomers I as well as polymers and copolymers incorporating such monomer units are useful as initiators, or precursors thereof, for the polymerization of isobutylene under cationic conditions to give graft copolymers containing both styrenic and isobutylenic units. These copolymers have commercial applications such as rubbers, coatings, and luricants.

Abstract: A crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is produced by curing the corresponding uncrosslinked polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen (e.g., zinc oxide) in combination with a bifunctional dienophile (e.g., a bismaleimide). The uncrosslinked elastomeric polymer is particularly suitable for use in the pharmaceutical industry, for example, for container closures. Shaped rubbery products comprising the crosslinked copolymer are also provided.

Abstract: Disclosed is an improved process of the post-emulsion method capable of forming crosslinked resin particles which do not have fusion bonds between particles and which have good storage stability and good redispersibility in an aqueous medium. The process comprises (a) dispersing in an aqueous medium a resinous component comprising (I) a base resin having a glass transition temperature (Tg) of 0.degree. C. or less and a polymerizable double bond, (II) a monomer which, when polymerized, provides a resin of which Tg is 20.degree. C. higher than that of said base resin, or a resin of which Tg is 20.degree. C. higher than that of the base resin, and (III) a polyvinyl compound; (b) crosslinking inside the dispersed resin particles and; (c) removing the aqueous medium therefrom.

Abstract: A poly(vinyl chloride) product is provided containing as a permanent plasticizer, a copolymer of vinyl acetate and ethylene which is copolymerized in the presence of porous particles of the PVC. The copolymerization is carried out in either suspension or emulsion and under conditions which provide a copolymer containing 60 to 85 wt % vinyl acetate in amounts from about 20 to 60 wt % of the vinyl acetate/ethylene copolymer in the final composition. A free flowing powder is formed which can be used for PVC compounding operations. If over 60 up to 80 wt % of the composition contains the copolymer, the product is a reinforced VAE dispersion.

Abstract: Polymer particles prepared by polymerizing polymerizable monomers by seed polymerization, with far more excellent polymerization stability than conventional seed polymerization processes, in the presence of a polymer emulsion comprising low molecular weight polymer particles, radically polymerizable in an aqueous system. The polymer particles are present in an amount of 0.5-30 parts by weight (on solid basis) per 100 parts by weight of polymerizable monomers, have a weight average molecular weight of 500-10,000 and are prepared by emulsion polymerization or soap-free polymerization. The seed polymerization is carried out by initially charging less than 30% by weight of said polymerizable monomers to the polymerization mixture, and after the polymerization conditions are established, by continuously or intermittently adding the remaining portion of said polymerizable monomers to the reaction system.

Abstract: A concentrate comprising a carrier polymer and at least 30%, by weight of the carrier polymer, of at least one modifying agent for a thermoplastic polymer is disclosed. The carrier polymer is a polymer of alpha-olefins having a heat of crystallization of less than 70 J/g and, if the copolymer is an ethylene/vinyl acetate copolymer, containing at least 18% by weight of vinyl acetate comonomer. The modifying agent is absorbed into the carrier polymer. In embodiments, the modifying agent is a polymerizable monomer. The concentrates provide a versatile method of addition of modifying agents into thermoplastic polymers.

Abstract: A rubber composition comprising a polymer obtained by adding maleic anhydride or a derivative thereof to a nitrile-group-containing highly saturated polymer rubber having an iodine value of 80 or less, which can be widely utilized in belts, hoses such as for hydraulic ones.

Abstract: A comb copolymer consisting of a methacrylic macromonomer as a branch ingredient and acrylic ester as a backbone ingredient and being suitable for an acrylic elastomer material which is excellent in transparency, weatherability and mechanical strength; an impact resistant acrylic resin composition obtained by blending the above comb copolymer with a PMMA (co)polymer; and a comb copolymer similarly consisting of a methacrylic macromonomer as a branch component and acrylic ester as a backbone component and being an acrylic resin which is excellent in transparency, weatherability, gloss and light resistance, are disclosed in this invention.Preparation methods of the high molecular weight comb copolymers useful for molding materials comprising the above mentioned comb copolymers are disclosed.

Abstract: A process for producing a polymer crosslinkable by exposure to moisture in the presence of a hydrolysis/condensation catalyst comprising blending (i) a thermoplastic base polymer, (ii) a solid carrier polymer containing a silane, and (iii) a free radical generator; heating and mixing (i), (ii) and (iii) together at a temperature above the crystalline melting point of said base polymer; optionally, a free-radical generator, hydrolysis/condensation catalyst, and other additives are contained in the solid carrier polymer.

Abstract: A thermosetting resin composition comprising(A) 60 to 95% by weight of a prepolymer or precopolymer selected from the group consisting of (A-1), (A-2) and (A-3) below,(A-1) a prepolymer of diallyl phthalate,(A-2) a precopolymer of diallyl terephthalate derived from diallyl terephthalate of the following formula (1) ##STR1## and an aromatic benzyl hydrocarbon having at least one hydrogen atom at the benzyl position and represented by the following formula (2) ##STR2## wherein each of R.sup.1 and R.sup.2 represents a member selected from the class consisting of a hydrogen atom and lower alkyl groups, and n is an integer of 1 to 3, and(A-3) a mixture of (A-1) and (A-2), and(B) 40 to 5% by weight of a polyacrylate or polymethacrylate of dipentaerythritol having at least 4 acryloyl or methacryloyl groups in the molecule and represented by the following formula ##STR3## wherein each R.sup.3 represents a hydrogen atom, --COCH.dbd.CH.sub.2 or ##STR4## and at least four R.sup.3 groups represents --COCH.dbd.CH.sub.

Abstract: Stable spray-coatable, water base composition having about 2 percent solids, that dries into speckled films having a plurality of different colored surfaces resistant to flaking, comprising: a blend of a surfactant free first solution comprising, butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, glacial methacrylic acid and styrene; a blend of a self-crosslinking second solution comprising, 2-ethylhexyl acrylate, butyl methacrylate, glacial methacrylic acid, styrene and at least one cross-linking polymer; a thickener gel; different colored dried latex paint chips, and ammonia.

Abstract: Stable spray-coatable, water base composition having about 2 percent solids, that dries into glittering film having plurality of reflective surfaces resistant to flaking, comprising: a blend of a surfactant free first solution comprising, butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, glacial methacrylic acid and styrene; a blend of a self-crosslinking second solution comprising, 2-ethylhexyl acrylate, butyl methacrylate, glacial methacrylic acid, styrene and at least one cross-linking polymer; a thickener gel; transparent polyethylene terephthalate chips on which reflective material has been vacuum deposited and cured fast by an epoxy resin, and ammonia.

Abstract: An improved process for forming hydroperoxide derivatives of rubbery polymers. The hydroperoxide derivatives being particularly well suited for use as intermediates in forming graft rubbery polymers. The process involves dissolving a rubbery polymer in a monomer mixture and adding to the rubbery polymer/monomer mixture a photosensitizing agent. The rubbery polymer-monomer mixture is then oxygenated and exposed to light under conditions wherein triplet oxygen is converted to singlet oxygen. The improvement comprises adding to the rubbery polymer/monomer mixture a solvent capable of solubilizing the photosensitizing agent in the rubbery polymer/monomer mixutre. The solubilizer increases the yield of hydroperoxide derivatives of rubbery polymers formed by a factor of 3.

Abstract: A process is provided according to the present invention comprising the steps of: functionalizing a base polymer by grafting alpha-beta unsaturated carboxylic acid, anhydride or ester to a base polymer, the base polymer being selected from the group of hydrogenated polymer of a conjugated diolefin and a copolymer of conjugated diolefins and monoalkenyl arenes, the grafting being performed in a blending device capable of imparting high mechanical energy and in the presence of 3 to 15 percent by weight, based on base polymer, of a suitable diluent oil; reacting the functionalized polymer with an amine; and recovering an animated polymer. This process results in a lower level of scission, crosslinking and coupling than processes which are essentially oil free. The product of this process is an excellent lubricating oil viscosity index improver and additionally has dispersant characteristics.

Abstract: A process for the polymerization of selected acrylic and maleimide monomers by contacting the monomers with a diazotate, cyanate or hyponitrite, and N-chlorosuccinimide, N-bromosuccinimide or a diazonium salt. The polymers produced can themselves initiate further polymerization. Block copolymers can be produced.

Abstract: A comb copolymer consisting of a methacrylic macromonomer as a branch ingredient and acrylic ester as a backbone ingredient and being suitable for an acrylic elastomer material which is excellent in transparency, weatherability and mechanical strength; an impact resistant acrylic resin composition obtained by blending the above comb copolymer with a PMMA (co)polymer; and a comb copolymer similarly consisting of a methacrylic macromonomer as a branch component and acrylic ester as a backbone component and being an acrylic resin which is excellent in transparency, weatherability, gloss and light resistance, are disclosed in this invention.Preparation methods of the high molecular weight comb compolymers useful for molding materials comprising the above mentioned comb copolymers are disclosed.

Abstract: Vinyl ether copolymers and a method of preparing the same. The vinyl ether is copolymerized with styrene, alkyl-substituted styrenes, alkoxy-substituted styrenes and mixtures thereof. In the process, a cadmium halide is used with hydrogen iodide or a suitable iodine containing electrophile, as the coinitiator.

Abstract: Novel heat-curable elastomeric polymers are produced which comprise an elastomeric base polymer modified by the presence on the elastomeric base polymer molecule of at least one pendant carboxylic acid ester group wherein the ester moiety contains certain types of reactive unsaturation. In a preferred embodiment, the base polymer is a selectively hydrogenated block copolymer of the poly(vinylaromatic compound)/polyalkadiene type, and the ester moiety is propargyl.

Abstract: Novel heat-curable elastomeric polymers are produced which comprise an elastomeric base polymer modified by the presence on the elastomeric base polymer molecule of at least one pendant carboxylic acid ester group wherein the ester moiety is alkyl arylcyclobutene. In a preferred embodiment, the base polymer is a selectively hydrogenated block copolymer of the poly(vinylaromatic compound)/polyalkadiene type, and the ester moiety is methylbenzocyclobutene.

Abstract: Butadiene is polymerized alone or with a monomer such as styrene in a dispersion in propane, butane or its mixtures with minor amounts of other C.sub.4 -C.sub.6 alkanes, e.g., n-pentane and a dispersant which is preferably a styrene/hydrogenated isoprene block copolymer to achieve stable dispersions at higher solids and butadiene levels possible with similar alkane dispersants.

Abstract: An adhesive composition comprising:a polymer latex containing a copolymer which comprises(a) 40 to 80% by weight of a conjugated diene monomer and(b) 0.5 to 30% by weight of a cyanated vinyl monomer,(c) 5 to 35% by weight of vinylpyridine and(d) not more than 53% by weight of an aromatic vinyl monomer; anda resorcin-formalin resin, which composition can adhere various fibers to rubbers.

Abstract: Block copolymers compose a polyisobutylene rubbery soft segment of M.sub.n of about 5,000 to above 500,000 and glassy hard segments of M.sub.n of about 5,000 or higher and usually about 10,000 to 35,000 or more, are made by preparing a living polymer block of the polyisobutylene and then polymerizing on said living polyisobutylene block the glassy hard segments by adding thereto an electron donor having a donor number of 15 to 50 and then adding and polymerizing the monomers for the glassy hard segments. The monomers for the glassy hard segments are styrene and its derivatives and indene and its derivatives and mixtures thereof.

Abstract: Polyvinyl chloride resins are treated with a low inherent viscosity-high glass transition temperature enhancing agent to impart improved processing properties thereto, especially melt flow, which are desirable in various melt type fabrication processes such as custom injection molding. The high glass transition temperature-inherent viscosity enhancing agent is made by polymerizing one or more high glass transition temperature agent forming monomers in the presence of a chain transfer agent. The agent has a high glass transition temperature as well as a low inherent viscosity. The high glass transition temperature-inherent viscosity enhancing agent is produced as an overpolymer in a mass polymerization reaction.

Abstract: Block copolymers compose a polyisobutylene rubbery soft segment of M.sub.n of about 5,000 to above 500,000 and glassy hard segments of M.sub.n of about 5,000 or higher and usually about 10,000 to 35,000 or more, are made by preparing a living polymer block of the polyisobutylene and then polymerizing on said living polyisobutylene block the glassy hard segments by adding thereto an electron donor having a donor number of 15 to 50 and then adding and polymerizing the monomers for the glassy hard segments. The monomers for the glassy hard segments are styrene and its derivatives and indene and its derivatives and mixtures thereof.