| 摘要 |
Waterproof sheet material comprises an ethylene copolymer film base, which copolymer has rubber-like properties and a modulus of elasticity lower than that of polyethylene, and on at least one face of the film, fibres or particles in which a portion only of the individual fibres or particles is embedded into the surface of the film so that the film has a pile surface. The copolymer may be an ethylene-vinyl acetate, ethylene-propylene copolymer such as ethylene-propylene rubber. Organic or inorganic fibres and particles may be adhered to the film e.g. polyolefin, polyamide, polyester, polyvinyl alcohol fibres, asbestos, punice, vermiculite, slag, glass. The pile material is deposited on the film base whilst the film is heat softened, and the film hardened by cooling. Mechanical and electrostatic methods of deposition may be used e.g. the pile material may be scattered on the film immediately after the film has been formed by melt extrusion, or the extruded film passed through an electrostatic field and the pile material deposited electrostatically. The pile material may be deposited as a number of spaced areas. The waterproof sheet material may be superposed upon a concrete or mortar base using a cement paste whereby the fibres or particles on the film become embedded in the paste, and covering mortar applied to the waterproof sheet, or the waterproof sheet may be applied to the cement or mortar base before it has solidified. Asphalt or other adhesive may be used instead of cement paste. The sheet may be applied to parapets, vertical walls. Tests for measuring the adhesive strength of the "piled" films on concrete are described. In Example (1) ethylene-vinyl acetate copolymer is extruded on an endless belt and asbestos applied by scattering, after which the film is passed through squeezing rolls then cooled and excess material brushed off and removed by vacuum. Both sides of the film may be covered by scattering pile material on the belt beforehand. In Example (2) ethylene-vinyl acetate copolymer is extruded on to an endless belt, is heated by an infra red lamp, and nylon fibres are applied, electrostatically insecure fibres being eliminated by suction. Apparatus for carrying out the process is illustrated. |
