Abstract: A method of producing a waterproof, gas-permeable composite sheet comprising the steps of: (a) preparing a film from a composition comprising 40-70 weight % of an ethylene-propylene-diene copolymer and 30-60 weight % of an ethylene-vinyl acetate copolymer; and (b) adhering the film to a woven or nonwoven fabric by hot pressing while causing the heat shrinkage of the film simultaneously, thereby making the film microporous. The composition may further contain linear low-density polyethylene to improve film-forming properties. By subjecting the hot-pressed composite sheet to a plurality of heating-cooling steps, it is provided with high heat resistance. In addition, by foaming the film and hot-pressing it to a stretchable woven or nonwoven fabric and then stretching, the composite sheet is further provided with high stretchability.

Abstract: A polyolefin composition incorporating in 100 parts by weight of a polyolefin, (A) 0.05 to 1 part by weight of a hindered amine type compound, (B) 0.02 to 1 part by weight of an organic phosphorus type compound, and (C) 0.02 to 0.5 part by weight of hydrotalcite.

Abstract: A polyolefin composition comprising (a) polyolefin, (b) vegetable fibers mainly composed of cellulose fibers, and (c) a deodorizer selected from the group consisting of a combination of a metallic soap and an amine antioxidant, activated carbon, zeolite and a phosphorus compound. Because of the deodorizer, the polyolefin composition has substantially no odor without sacrificing mechanical properties thereof. Accordingly, it may be used suitably for car parts required to have high mechanical strength with substantially no odor, such as unit cases of air conditioners.

Abstract: A method of manufacturing a plastic pipe having a spiral ridge on an outer surface and a flat inner surface, comprising the steps of: (a) supplying a plastic ribbon in a softened state onto a plurality of rotating forming rolls arranged circularly, so that the plastic ribbon is spirally wound around the forming rolls while partially overlapping to be fused with each other; (b) spirally winding an endless forming core belt around the forming rolls in such a manner that the endless forming core belt is sandwiched between the plastic ribbon already wound around the forming rolls and the plastic ribbon newly supplied, thereby providing the resulting plastic pipe with a spiral ridge; (c) cutting the spiral ridge after the plastic ribbon is fused with each other and sufficiently cooled, thereby providing the spiral ridge with a slit extending along it to remove the endless forming core belt from it; and (d) winding a second plastic ribbon in a softened state around the spiral ridge to fuse the second plastic ribbon

Abstract: Disclosed is a method for the production of a gas-pervious composite film comprising the steps of unaxially or biaxially drawing a film composed of a crystalline polyolefin resin, a rubbery polymer, and a filler thereby forming a drawn film, joining said drawn film to a meshed sheet by hot pressing at a temperature exceeding the temperature at which said drawn film begins to undergo thermal shrinkage thereby fastening said drawn film to said meshed sheet and, simultaneously, causing thermal shrinkage of said drawn film and consequently imparting a microporous texture to said film.

Abstract: (A) polypropylene (10-90 weight part), (B) halogenated butyl rubber (90-10 weight part, (A)+(B)=100 weight part), (C) olefinic rubber (10-120 weight part) and (D) mineral oil softening agent (5-120 weight part) are heated in the presence of (E) metal oxide and/or metal chloride. To 100 weight part of the resulting composition are added, (F) polyolefin (100-600 weight part) and (G) vulcanizable olefinic rubber (50-500 weight part) and the components are mixed and heated in the presence of (H) organic peroxide. The resulting thermoplastic elastomer composition has good paintability, moldability, compatibility, low temperature impact strength, and especially high stiffness at elevated temperature.

Abstract: The invention relates to the process of the invention provides a radiation-crosslinked polypropylene foam by extrusion at a low temperature (about 170.degree. C.) below the decomposition point of the blowing agent. The resulting foamed item has by far better heat resistance than conventional ones.The raw resin can be prepared by mixing a resin in the pellet form and a blowing agent in the powder form on account of the low-temperature flowability. Heretofore, such mixing was impossible because the blowing agent does not disperse completely.This outstanding effect of the invention was not expected at all from the known prior arts.