| 摘要 |
A bonded non-woven web, to be used in making laminates (see Division B5) has a density between 15 and 45 lbs/cu. ft., and is of molecularly oriented synthetic organic polymeric fibres. The fibres are bonded by heat or solvent fusing or by up to 120% of a binder such as emulsified P.V.C., polyurethane or polyesters. The web may comprise several layers united by needle punching and/or bonding or fusing. Suitable drawn fibres, which may be continuous or staple and at least one inch in length, include poly (polymethylene terephthalate), e.g. polyethylene terephthalate, or polyhydrocarbons, e.g. polypropylene. The fibres should be of a size between 1 and 20 d.p.f., have a tensile modulus of at least 10 g.p.d., have a break extensibility of from 5 to 400%, have a moisture regain of less than 5% at 65% RH and 21 DEG C, have a creep of less than 1% per hour under a tensile load of 20% of their breaking point, and have a dimensional stability of less than /sB2% variation in length between 0 DEG and 100 DEG C. In examples,: (I) describes the making of an 18 oz. per sq. yd. web comprising six needled and heat-fused baths of polypropylene fibres. (V) a web as in (I) is produced except that bonding is by means of a 25% aqueous P.V.C. emulsion. The web is then cured. (VI) describes the making of baths of polyethylene terephthalate fibres which are plied together by needling and impregnation as in (V). |
