Abstract: Blends of amorphous and semicrystalline polymers having shape memory properties were prepared by blending a crystalline polymer such as poly(vinylidene fluoride), polylactide, poly(hydroxxybutyrate), poly(ethylene glycol) polyethylene, polyethylene-co-vinyl acetate, poly(vinyl chloride), poly(vinylidene chloride) and copolymers of poly(vinylidene chloride) and poly(vinyle chloride) and an amorphous polymer such as poly(vinyl acetate), poly methyl acrylate, poly ethyl acrylate, atactic poly methyl methacrylate, isotactic poly methyl methacrylate, syndiotactic poly methyl methacrylate and other poly alkyl methacrylates. The method for preparing the polymeric materials and applications thereof, for example, as smart medical devices, are also disclosed.

Abstract: Radical polymerization process for the preparation of halogenated polymers employing one or more ethylenically unsaturated monomers, at least one of which is chosen from halogenated monomers, molecular iodine and one or more radical-generating agents chosen from diazo compounds, peroxides and dialkyl diphenylalkanes Radical polymerization process for the preparation, starting from the halogenated polymers prepared by the process as described above, of block copolymers, at least one block of which is a halogenated polymer block. Halogenated polymers which have a number-average molecular mass Mn of greater than 1.0×104 and an Mz/Mw ratio of less than 1.65. Block copolymers, at least one block of which is a block of halogenated polymer identical to the halogenated polymers described above. Block copolymers comprising at least one halogenated polymer block which have a number-average molecular mass Mn of greater than 1.5×104 and a polydispersity index Mw/Mn of less than 1.60.

Abstract: Physical blends of solid particulates of chlorinated polyolefins and elastomeric ethylene copolymers yield a blended product with anti-blocking characteristics superior to that defined by the weight proportion-based linear interpolation of either blend component. The blend compositions are useful as impact modifiers for polyvinyl chloride compositions.

Abstract: A thermoplastic elastomer composition characterized in that the composition comprises a resin component and at least two kinds of rubber components, wherein at least one kind of the rubber components makes a continuous phase and/or a network-like phase, and the remaining at least one kind of the rubber components makes an isolated phase; and a process for producing the same.

Abstract: A plastic composition including polymeric nanoparticles having a diameter of 1 to 100 nanometers, and a polymeric component. Also provided is a method for providing such a plastic composition.

Abstract: The use of polytetrafluoroethylene micropowders having a particle size of generally less than about 20 microns as an additive for polyvinyl chloride or polyolefin unexpectedly produces compositions which are melt processable. Other unexpected properties include that the micropowder is deformable under shear and acts as a flame retardant.

Abstract: Disclosed are techniques and related material blends for improving adhesion between a polyolefin film and a pressure sensitive adhesive, and also significantly decreasing the coefficient of thermal expansion of a polyolefin film by modifying the chemical properties of the film. Specifically, particular amounts of a modifying polymer and/or copolymer such as ethylene vinyl acetate are incorporated into the polyolefin film. The polyolefin film may for instance be either a polyethylene or polypropylene film.

Abstract: Multilayer blow molded containers, which comprise a layer of an ethylene-vinyl alcohol copolymer (A) having an ethylene content of 5 to 60% by mol and a degree of saponification of 85% or more and a layer of a resin composition (B), characterized in that the resin composition (B) comprises 1 to 40% by weight of a thermoplastic resin (b1) having at least one functional group selected from the group consisting of boron-containing groups that are convertible to a boronic acid group in the presence of water and a boronic acid group (hereinafter, referred to as a boron-containing functional group), and 60 to 99% by weight of polypropylene (b2), exhibit excellent gas-barrier properties, have good interlayer adhesion, have excellent thermal stability, and are low in production cost.

Abstract: Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a fluoropolymer process aid by means whereby the weight average particle size of the fluoropolymer is greater than 2 microns as it reaches the extruder die entrance.

Abstract: A polyvinyl chloride fiber which comprises a composition having 100 parts by weight of a vinyl chloride resin, from 3 to 20 parts by weight of a chlorinated vinyl chloride resin having a chlorine content of from 57.0 to 62.0% and an average polymerization degree of from 550 to 750, and from 5 to 50 parts by weight of a chlorinated vinyl chloride resin having a chlorine content of from 65.0 to 67.0% and an average polymerization degree of from 550 to 750.

Abstract: An adhesive composition, including a mixture of about 1 percent to about 35 percent by weight of chlorinated polymer, about 1 percent to about 35 percent by weight of a nitrile elastomer, a rubber-modified acrylonitrile copolymer, or mixtures thereof, about 25 percent to about 90 percent by weight of an alkyl acrylate or methacrylate monomer and about 0.01 to about 30 weight percent of a core shell impact modifier.

Abstract: The present invention is specifically directed to improved polyvinyl chloride compositions having excellent impact strength. In particular, the impact resistant composition comprises a vinyl chloride polymer and 2-8 parts of an impact modifier composition comprising at least one ethylene/alpha-olefin copolymer and at least one chlorinated olefin polymer per 100 parts of the vinyl chloride polymer. Preferably the impact modifier composition comprises less than 1 part of the ethylene/alpha-olefin copolymer and the ratio of said copolymer to the total modifier composition is less than 25%.

Abstract: A process for making a textured coating on a substrate and compositions for such coatings are disclosed wherein coating mixtures comprising un-expanded micro-capsules and a plastisol or other suitable resins are applied to the substrate and subsequently heat treated to expand the micro-capsules within the coating. The expanded micro-capsules create an aesthetically pleasing surface texture in the coating while retaining the desired wear-resistant properties of the coating.

Abstract: The present invention is specifically directed to improved polyvinyl chloride compositions having excellent impact strength. In particular, the impact resistant composition comprises a) a vinyl chloride polymer, b) at least one ethylene/alpha-olefin copolymer, said copolymer having a density of 0.858 to 0.91 g/cc and having a melt index from an I10 value of 0.1 to an I2 value of 10, and c) at least one randomly chlorinated olefin polymer having a chlorine content of from 20-40 percent by weight, the feedstock for said chlorinated olefin polymer having a melt index from an I10 value of 0.1 to an I2 value of 10. Optionally, these impact resistant polyvinyl chloride compositions may have inorganic filler levels from 5 to 50 parts per hundred relative to the polyvinyl chloride polymer.

Abstract: The present invention provides a moulding composition, which includes: a plurality of bead polymers dispersed in at least one matrix polymer; wherein the bead polymers: have an average particle size of 5 to 40 &mgr;m, and have a refractive index nD at 20° C. which is different from a refractive index nD at 20° C. of said matrix polymer; and wherein the bead polymers are prepared by a process, which includes: contacting: at least one polymerizable mix which includes at least 50% by weight of at least one (meth)acrylate monomer, at least one aluminum compound, and an aqueous phase, to prepare a mixture; dispersing the mixture at a shear rate ≧103 s−1 to form a dispersion, wherein the dispersion is stabilized by the aluminum compound; and polymerizing to produce the bead polymers having an average particle size of 5 to 40 &mgr;m.

Abstract: A melt-mixed blend of plasticized PVC, fluoropolymers, and a compatibilizer having acrylate functionality exhibits good mechanical and dielectric properties and is useful for wiring and cable applications.

Abstract: Polymeric materials that differ from each other in solubility parameters and other properties are covulcanized by reaction with a hydrogenated carboxylated nitrile rubber, a multivalent salt of an organic acid and a curing agent.

Abstract: The invention relates to antimicrobial polymers and polymer blends which are prepared by polymerizing a monomer of the formula I: where R1=—H or —CH3 R2=branched or unbranched aliphatic hydrocarbon radical having from 1 to 5 carbon atoms, R3=H, or branched or unbranched aliphatic hydrocarbon radical having from 1 to 7 carbon atoms, R4=H, or branched or unbranched aliphatic hydrocarbon radical having from 1 to 7 carbon atoms, R5=H, or branched or unbranched aliphatic hydrocarbon radical having from 1 to 7 carbon atoms, and X=O, NH, NR5 and, where appropriate, then mixing with at least one other polymer. The antimicrobial polymers or blends may be used for producing hygiene items or items for medical technology, e.g. as a coating, or else in surface coatings or protective paints. They may also be used in a process for eliminating/reducing biofouling in water systems.

Abstract: Blends of amorphous and semicrystalline polymers having shape memory properties were prepared by blending a crystalline polymer such as poly(vinylidene fluoride), polylactide, poly(hydroxxybutyrate), poly(ethylene glycol) polyethylene, polyethylene-co-vinyl acetate, poly(vinyl chloride), poly(vinylidene chloride) and copolymers of poly(vinylidene chloride) and poly(vinyle chloride) and an amorphous polymer such as poly(vinyl acetate), poly methyl acrylate, poly ethyl acrylate, atactic poly methyl methacrylate, isotactic poly methyl methacrylate, syndiotactic poly methyl methacrylate and other poly alkyl methacrylates. The method for preparing the polymeric materials and applications thereof, for example, as smart medical devices, are also disclosed.

Abstract: The present invention is specifically directed to improved polyvinyl chloride compositions having excellent impact strength. In particular, the impact resistant composition comprises a) a vinyl chloride polymer, b) at least one ethylene/alpha-olefin copolymer, said copolymer having a density of 0.858 to 0.91 g/cc and having a melt index from an I10 value of 0.1 to an I2 value of 10, and c) at least one randomly chlorinated olefin polymer having a chlorine content of from 20-40 percent by weight, the feedstock for said chlorinated olefin polymer having a melt index from an I10 value of 0.1 to an I2 value of 10. Optionally, these impact resistant polyvinyl chloride compositions may have inorganic filler levels from 5 to 50 parts per hundred relative to the polyvinyl chloride polymer.

Abstract: The present invention provides a vinyl chloride resin composition having excellent mechanical properties. The vinyl chloride resin composition comprises a chlorinated polyolefin and a resin composition containing a vinyl chloride resin and a polyolefin resin, in which 1 to 30 parts by weight of the chlorinated polyolefin is included relative to 100 parts by weight of the resin composition including 50 to 99 parts by weight of the vinyl chloride resin containing 0 to 50% by weight of a plasticizer and 1 to 50 parts by weight of the polyolefin resin, and in which the chlorinated polyolefin has a heat of fusion of 10 to 100 J/g, which is measured in accordance with a DSC method, and includes 35 to 60% by weight of chlorine in amorphous portions thereof.

Abstract: In the present invention, the polymer composition is produced by polymerizing an anionically or cationically polymerizable monomer in the presence of a highly syndiotactic styrenic polymer and optionally a rubber-like polymer. The polymer composition thus obtained is improved in its solvent resistance without using any particular compatibilizer and has a good moldability.

Abstract: It is disclosed a wateborne composition comprising styrene-acrylic latex having a glass transition temperature (Tg) of from about 0° C. to about 30° C., vinylidene chloride-containing polymer latex and at least one filler. The composition exhibits sound damping property at both low and high frequencies as well as chip resistance and abrasion resistance. The composition is effective for use in the transportation industry, the building industry, the aerospace industry and the appliance industry.

Abstract: Sheets of thermoplastic material for lining structural containers and conduits, and having portions of their surfaces at the edges to be joined to each other treated with urethane, are joined and sealed by a strip of polyvinyl chloride, the interacting surface of which is prepared by hydroxyl modification for sealing with the thermoplastic sheets. The joinder is accomplished by a method that dispenses with any necessity of specially treating the surfaces at any prescribed time prior to accomplishing the joinder, and dispenses with any requirement for heat elevation during joinder. A method of joinder with the thermoplastic sheets alone is also shown.

Abstract: A multilayer injection blow molded container of this invention, containing a layer of a specific ethylene-vinyl alcohol copolymer (A) and a layer of a resin composition (B) comprising a thermoplastic resin (b1) having a specific functional group and polypropylene (b2), is disclosed, having characteristics that it has excellent gas-barrier properties, has good interlayer adhesion, has excellent thermal stability and can be produced with a low cost.

Abstract: The present invention provides a coating composition for automotive upholstery, with which a 1-coat finish of not yet surface-treated (pretreated) plastic materials such as polyolefin materials can be performed, and which is aqueous, and excellent also in chemical resistance. The aqueous coating composition for automotive upholstery comprises a resin emulsion as an essential component, wherein the resin emulsion includes poly(olefin chloride) resin emulsion A and pure acrylic resin emulsion B in a weight ratio (A/B) of 25/75˜30/70 in terms of solid content, wherein poly(olefin chloride) resin emulsion A is an emulsion of a poly(olefin chloride) resin having a chlorine content of 22˜25 wt % in terms of solid content and a weight-average molecular weight of 60,000˜80,000, and wherein pure acrylic resin emulsion B is an emulsion of a pure acrylic resin having a glass transition temperature of not lower than 40° C.

Abstract: A process for making MD (machine direction) oriented polyethylene film is disclosed. The process comprises blending a high-molecular weight, medium-density polyethylene (HMW MDPE) and a linear low-density polyethylene (LLDPE), converting the blend into a thick film, and orienting the thick film into a thinner film in the machine direction. The resulting film has high modulus, high gloss, low haze, and relatively high MD tear and dart impact.

Abstract: Compositions of a polyvinyl chloride resin, a polyolefin which is the metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer, and a component selected from the group consisting of chlorinated polyethylene, polycaprolactone, and combinations thereof are disclosed. The compositions are essentially free of liquid plasticizers, and prossess good mechanical properties of tensile strength, elongation, and a low brittle point, even after being subjected to high heat for an extended period of time.

Abstract: There is provided an excellent impact modifier for a vinyl chloride resin. There is used, as an excellent impact modifier, a copolymer which is prepared by polymerizing 10 to 70% by weight of a monomer or monomers containing 60 to 100% by weight of at least one vinyl monomer selected from the group consisting of a (meth)acrylate compound, an aromatic vinyl compound, a vinyl cyanide compound and vinyl chloride, and 0 to 40% by weight of the other monomer copolymerizable therewith, in the presence of 30 to 90% by weight of a hollow rubber particle of which glass transition temperature Tg is at most 0° C. and a void ratio is 3 to 90% by volume in a latex state, and which contains a cross linking agent in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total rubber component monomer.

Abstract: Adhesive composition, including a mixture of about 1 percent to about 35 percent by weight of chlorinated polymer, about 1 percent to about 35 percent by weight of a nitrile elastomer, a rubber-modified acrylonitrile copolymer, or mixtures thereof, and about 25 percent to about 90 percent by weight of an alkyl acrylate or methacrylate monomer.

Abstract: The present invention is specifically directed to improved polyvinyl chloride compositions having excellent impact strength. In particular, the impact resistant composition comprises a) a vinyl chloride polymer, b) at least one ethylene/alpha-olefin copolymer, said copolymer having a density of 0.858 to 0.91 g/cc and having a melt index from an I10 value of 0.1 to an I2 value of 50, preferably from an I10 value of 0.1 to an I2 value of 30, and most preferably from an I10 value of 0.1 to an I2 value of 20, and c) at least one randomly chlorinated olefin polymer having a chlorine content of from 20-40 percent by weight, the feedstock for said chlorinated olefin polymer having a melt index from an I10 value of 0.1 to an I2 value of 10. Optionally, these impact resistant polyvinyl.chloride compositions may have inorganic filler levels from 5 to 50 parts per hundred relative to the polyvinyl chloride polymer.

Abstract: Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a process aid package comprising at least two unimodal fluoroelastomers having different Mooney viscosities.

Abstract: A method of making polymeric particulates wherein polymeric scrap material such as in the form of film waste is supplied to intermeshing pulverizer screws which are rotated to transport the polymeric material along their length and subject the polymeric material to solid state shear pulverization and in-situ polymer compatibilization. Uniform pulverized particulates are produced without addition of a pre-synthesized compatibilizing agent. The pulverized particulates are directly melt processable (as powder feedstock) and surprisingly yield a substantially homogeneous light color product. The polymeric film waste containing high proportions of LDPE yield molded articles of superior notched izod impact strength and elongation. Compatibilized polymeric particles can be formed even if the polymeric scrap material includes cellulose materials such as paper, cardboard and wood.

Abstract: A process for producing a succinimide resin composition is provided which comprises reacting a maleic anhydride-olefin type copolymer constituted of 40-60 mol % of maleic anhydride units, 60-40 mol % of olefin units, and 0-20 mol % of a copolymerizable monomer units with one or more amine compounds for imide formation in the presence of a second polymer other than the succinimide resin. This process improves the productivity by lowering the torque in the extrusion reaction, giving a succinimide copolymer resin composition having low yellowness and high transparency with high production efficiency.

Abstract: A novel composition is disclosed which comprises polyvinyl chloride, an ethylene-based copolymer as a compatibilizer, inorganic fillers and from about 5 to 95 percent by weight of either virgin or recycled/recovered polyvinyl butyral. A process for preparing this novel composition is also provided.

Abstract: A molded or formed product obtained by molding or forming a resin composition comprising (A) at least one vinyl cyclic hydrocarbon polymer selected from the group consisting of hydrogenated products of aromatic vinyl polymers, vinylcyclohexene polymers or hydrogenated products thereof, and vinylcyclohexane polymers, and (B) at least one substance selected from the group consisting of compounding additives incompatible with the polymer, organic compounds having at least one alcoholic hydroxyl group and at least one ether linkage, and organic compounds having at least one alcoholic hydroxyl group and at least one ester linkage, wherein the initial light transmittance (a) of the molded or formed product at an optional wavelength within a range of 400 to 800 nm and the light transmittance (b) of the molded or formed product after the molded or formed product is held for 1,000 hours in an atmosphere of 65° C.

Abstract: A molded or formed product obtained by molding or forming a resin composition comprising (A) at least one vinyl cyclic hydrocarbon polymer selected from the group consisting of hydrogenated products of aromatic vinyl polymers, vinylcyclohexene polymers or hydrogenated products thereof, and vinylcyclohexane polymers, and (B) at least one substance selected from the group consisting of compounding additives incompatible with the polymer, organic compounds having at least one alcoholic hydroxyl group and at least one ether linkage, and organic compounds having at least one alcoholic hydroxyl group and at least one ester linkage, wherein the initial light transmittance (a) of the molded or formed product at an optional wavelength within a range of 400 to 800 nm and the light transmittance (b) of the molded or formed product after the molded or formed product is held for 1,000 hours in an atmosphere of 65° C.

Abstract: The present invention provides a vinyl chloride resin composition having excellent mechanical properties. The vinyl chloride resin composition comprises a chlorinated polyolefin and a resin composition containing a vinyl chloride resin and a polyolefin resin, in which 1 to 30 parts by weight of the chlorinated polyolefin is included relative to 100 parts by weight of the resin composition including 50 to 99 parts by weight of the vinyl chloride resin containing 0 to 50% by weight of a plasticizer and 1 to 50 parts by weight of the polyolefin resin, and in which the chlorinated polyolefin has a heat of fusion of 10 to 100 J/g, which is measured in accordance with a DSC method, and includes 35 to 60% by weight of chlorine in amorphous portions thereof.

Abstract: An olefinic thermoplastic elastomer composition which does not exhibit problems due to a softening agent such as an oil is superior in molding processability. The thermoplastic elastomer composition is produced by a heat crosslinking process of a resin-rubber composition that contains an olefinic and/or diene rubber, an olefinic resin, and a vinyl copolymer. The vinyl copolymer is obtained by copolymerizing 20 wt % or more of a vinyl monomer represented by CH2═CHOCOR1 or CH2═CHOR2 wherein R1 and R2 are alkyl groups having 1-6 carbon atoms. The thermoplastic elastomer composition can include a vinyl copolymer that has not undergone a heat crosslinking process.

Abstract: An emulsion or suspension polymer comprising a vinyl chloride polymeric core and an acrylic ester-acrylonitrile polymeric shell is disclosed. The emulsion polymer is preferably prepared using a two-stage process. In the first stage, a vinyl chloride monomer is polymerized or copolymerized to form a first phase of a polymeric hard core having a relatively high chlorine content. In a second stage, the soft acrylic ester—acrylonitrile copolymer is made in situ in a reaction mixture comprising the first phase. The product provides both flame retardancy and low MFFT, and is useful in a variety of coating and binding applications.

Abstract: A composition includes greater than 50% by weight such as between 51% and 99% by weight, of a first PVdC copolymer having a weight average molecular weight of between 80,000 and 125,000, and less than 50% by weight, such as between 1% and 49%, by weight of a second PVdC copolymer having a weight average molecular weight of between 126,000 and 180,000, the weight percent of each of the first and second polymers based on the combined weight of the first and second polymers. A film includes at least one layer having the above composition. A film can have at least one layer including a blend of a first vinylidene chloride polymer and a second vinylidene chloride polymer, the film having a free shrink ratio of between 0.6 and 2.2 at a shrink temperature of 180° F., or a free shrink ratio of between 0.8 and 1.4 at a shrink temperature of 200° F. Methods of making the film of the invention are also disclosed.

Abstract: The present invention relates generally to compositions prepared by polymerizing vinyl neo C9-C13 carboxylic acid esters. Such compositions include latex compositions that are formed by polymerizing vinyl neo C9-C13 carboxylic acid esters with ethylenically unsaturated comonomers such as acrylic acid esters and vinyl acetate. The polymer compositions of the present invention are particularly suitable for use in applications such as architectural (both interior and exterior), direct-to-metal and marine coatings and transportation maintenance applications.

Abstract: A method of making a dry, solid, powdered flame retardant composition is disclosed. Polyvinyl chloride is mixed with about 20 to about 150 phr of a liquid flame retardant having the general formula at a temperature of about 50 to about 100° C., where R1 and R2 are independently selected from aliphatic from C2 to C20. Also disclosed are a dry, solid, powdered flame retardant composition made by this method, a method of making a flame retardant polymer by compounding that dry, solid, powdered flame retardant composition with a polymer, and a flame retardant polymer made by that method.

Abstract: A clear and printable polypropylene film is disclosed. The film is prepared from a blend of a polypropylene and an ethylene/alkyl acrylate copolymer. It has an excellent adhesion with commonly used inks without surface treatment.

Abstract: The invention concerns a dispersion powder composition which is redispersible in water and is made from water-insoluble organic polymers, the composition being characterized in that it contains 0.1 to 30% by wt., relative to the weight of the organic polymers, of one or more silicon compounds which are dispersible in water and which have a boiling point at normal pressure of 160 degrees C., selected from the group comprising the silanes, polysilanes, oligosiloxanes, carbosilanes, polycarbosilanes, carbosiloxanes, polycarbosiloxanes and polysilylenedisiloxanes. The invention also concerns methods for manufacturing such compounds and their use.

Abstract: The present invention provides a coating composition which is excellent in a curing property (particularly a low temperature curing property) of a coating film and which forms a coating film having excellent chipping resistance and adhesive property, and it comprises a hydroxyl group-containing resin (A), a cross-linking agent (B) and a phosphoric acid group-containing vinyl resin (C).

Abstract: A method of making an article from polyvinyl chloride compound that has a predetermined amount of gloss is disclosed. Samples of the resin are prepared that have different molecular weight distributions. Articles are made from the samples and the gloss of the articles is measured. The relationship between the molecular weight distributions of the samples and the gloss of the articles made therefrom is determined. From that relationship, an article is made from a resin selected such that its molecular weight distribution corresponds to the predetermined amount of gloss.

Abstract: A synthetic resin powder having improved powder characteristics such as granulation property and blocking resistance, which is obtained by coagulating a latex of an MBS resin satisfying the following relational equations (1) and (2): −1.5x+140≦y≦−1.65x+180  (1) 55≦x≦70  (2) wherein x is a butadiene content (% by weight) in the MBS resin, and y is a Vicat softening point (°C.) of the MBS resin, adding 0.1 to 10 parts by weight of a hard polymer per 100 parts by weight of the MBS resin in the state of latex or coagulated slurry to the resulting slurry of MBS resin, and recovering a powder from the resulting mixture. The resin powder is useful as an impact modifier for vinyl chloride resins and can impart an excellent impact resistance without impairing the transparency of vinyl chloride resins.

Abstract: A thermoplastic rubber composition prepared by crosslinking 1-99 parts by weight of a crosslinkable rubbery polymer (A) and 1-99 parts by weight of a polypropylene resin (B) (total amount of (A) and (B) being 100 parts by weight), wherein said (B) comprises a polypropylene resin (B-1) characterized by generation of a torque higher than Mo after melting and a polypropylene resin (B-2) characterized by generation of a torque not higher than Mo after melting, in a melting test of said (B) in the presence of an organic peroxide (temperature condition being at 200° C.), and Mo being a torque right after complete melting.

Abstract: A processing aid (B) for foam molding use which comprises a powdered copolymer composed of 50 to 80% by weight of methyl methacrylate, 20 to 50% by weight of an alkyl methacrylate having an alkyl group of 3 to 5 carbon atoms, and 0 to 20% by weight of other copolymerizable monomers, the copolymer having a reduced viscosity (&eegr;sp/c) of 4 to 8. Use of this processing aid permits vinyl chloride resins to be kneaded efficiently and imparts an increased melt strength thereto, so that fine and uniform foamed cells can be formed and, moreover, a high foaming ratio and an attractive molding appearance can be achieved.