Abstract: An oil control ring comprises: an oil ring having a pair of land parts arranged in a sliding direction and connected to each other by a web part; and a coil expander that biases the oil ring toward the outer circumferential side in the radial direction. The web part of the oil ring is provided with a plurality of window holes. In the axial cross-sectional view of the largest opening portion of the window hole in the axial direction of the oil ring, a width H1 in the sliding direction of the oil ring and a length L1 of a combustion chamber-side non-window hole part, which excludes the window hole, in the outer circumferential surface of the web part, satisfy the condition of 0.15>L1/H1?0.

Abstract: A resin composition comprising a graft copolymer of a rubbery polymer having a vinyl cyanide compound and an aromatic vinyl compound grafted thereon, and a copolymer comprising a vinyl cyanide compound and an aromatic vinyl compound. A molded article of the resin composition is characterized with improved coating performances.

Abstract: Rubber particles comprising a hydrogenated block copolymer of a conjugated diene and a vinyl aromatic compound, said particles having a glass transition temperature of -30.degree. C. or less, a gel content of at least 10%, an average particle size of 0.01 to 5.0 .mu.m, and a micro-phase separating structure having hard segments and soft segments, wherein hard segments and soft segments are alternately laminated together in the form of concentric multilayers, are useful in reinforcing resin compositions. A particular reinforced resin composition is comprised of a matrix resin having a glass transition temperature of at least 0.degree. C. and 1 to 60% by weight of the above defined rubber particles dispersed in the matrix resin. The rubber particles have a great reinforcing effect on the matrix resin and resin compositions reinforced with these rubber particles are characterized with superior weather resistance, heat stability and impact resistance properties.

Abstract: A process for producing a copolymer by continuously copolymerizing in a solution monomers comprising 40 to 95% by weight of an aromatic vinyl compound and 5 to 60% by weight of a vinyl cyanide compound, and further 0 to 30% by weight of a vinyl compound copolymerizable with the aromatic vinyl compound and vinyl cyanide compound, wherein 10 to 100 parts by weight of a solvent containing not less than 40% by weight of an alcohol is used as the polymerization solvent based on 100 parts by weight of the total amount of the monomers. According to the process, attachment of a gel-like polymer onto the polymerization vessel or device can be prevented. The copolymer is useful as a thermoplastic resin for various molded articles including electrical parts for domestic uses, automobile parts and commodity goods.

Abstract: A polymeric material which is superior in mechanical strength, dimensional stability, moldability and resistances to chemicals, heat and abrasion comprises a copolymer composed of polymer chain moieties of a copolymer containing an imide compound of an .alpha.,.beta.-unsaturated dicarboxylic acid and polymer chain moieties of a polyamide, both chain moieties being bonded to each other. The material may be blended with thermoplastic resins. Furthermore, the material may be reinforced with glass fiber, etc.

Abstract: Improved mold release is obtained in a styrene polymer by incorporating a mixture of fatty acid and metal fatty acid salt.