| 摘要 |
1391793 Non-woven fabric HOECHST AG 6 March 1972 [5 March 1971] 10367/72 Headings D1R and D2B [Also in Division B2] A fleece comprising inorganic fibres is stabilised by a binding agent containing polyvinyl alcohol, a thermosetting resin and an acid, and dried by heating at 100‹C to 250‹C. It may be coated with bitumen, asphalt, polyamide, polyester, polyvinyl chloride, polyvinyl acetate or a copolymer thereof, polyvinyl butyral, polyacrylate, polyethylene or polypropylene, and used in a laminate. The bitumen may be applied at 180 to 200‹C. The inorganic fibres are glass, asbestos, slag, rock or basalt. They may be mixed with up to 90% polyethylene, polypropylene, polyacrylonitrile, polyurethane, polyvinyl chloride, polycarbonate polyester or polyvinyl alcohol fibres. The binder comprises 5 to 50% of the total weight of the product. It is applied to the fleece in an aqueous solution by spraying, roll-coating or impregnating. Alternatively the fleece is formed from a suspension of fibres in the binding agent mixture. The polyvinyl alcohol has a molecular weight of 1000 to 4500, an ester number of 8 to 140 mg KOH/g and comprises 5% to 95% of the binder. The thermosetting portion comprises a condensate of formaldehyde, trioxan, glyoxal, acetaldehyde or benzaldehyde with urea, benzoguanamine, dicyaniamide, an aminotriazine e.g. melamine or ammeline, phenol, an alkyl, halo or polynuclear phenol or diphenylalpropane. The preferred acid is maleic anhydride. Many other acids are listed. The acid comprises 1% to 40% by weight of the binder, preferably 2%. |
