| 摘要 |
<p>1524857 Non-flammable fibre blends; fabrics E I DU PONT DE NEMOURS & CO 29 Oct 1975 [30 Oct 1974] 44720/75 Headings D1K and D1W [Also in Division B5] A non-flammable blend of textile fibres suitable for the production of non-flammable fabrics, comprises (a) from 20 to 40% by weight of a normally flammable textile fibre (defined as one which fails a specified vertical flame test), e.g. polyethylene terephthalate, cotton or acrylic fibres, and (b) from 60 to 80% by weight of poly(metaphenylene isophthalamide) fibre containing, distributed throughout its whole interior, a cross-linked reaction product of a tetrakis hydroxymethyl phosphonium compound, e.g. tetrakis hydroxymethyl phosphonium chloride (THPC), or tetrakis hydroxymethyl phosphonium oxide or a derivative thereof, with a resin selected from melamine formaldehyde and phenol formaldehyde or from hexamethylol melamine, the phosphonium compound being present in an amount of 5 to 20% of the poly (metaphenylene isophthalamide) fibre. The reaction product may additionally contain guanidine phosphate and a curing catalyst. The component (b) may be prepared by impregnating a tow of crimped, never-dried filaments of poly(mpi) with a solution containing THPC, melamine-formaldehyde resin and an ammonium chloride catalyst, drying and curing at 135‹C for 1.5 hours, or by steaming in an autoclave at 20 psig for 45 minutes. The scoured, rinsed, dried and cut to staple tow is then blended with the appropriate normally flammable textile fibre and the blend spun into a yarn e.g. of 13.5 Z twist and the yarn converted to a double or Jersey knit fabric or a batiste woven fabric which is non-flammable. Preferred blends include those containing 20- 30% by weight cotton, 20-25% by weight acrylic or 20-40% polyethylene terephthalate. A comparative treatment in which poly (paraphenylene terephthalamide) containing the cross-linked phosphorus reaction product is used as the non-flammable component (b) and is blended with polyethylene terephthalate staple fibres, is given. The poly(metaphenylene isophthalamide) tow is prepared by dry-spinning a solution of poly(metaphenylene isophthalamide) in N, N-dimethyl acetamide containing calcium chloride through multi-hole spinnerets, converging the extruded filaments at a guide where they are flooded with an aqueous solution containing dimethyl acetamide and calcium chloride, and combining several bundles of filament to form a wet tow which is fed through a 10-tank apparatus wherein it is extracted in aqueous baths and drawn in stages to a total of about 4.2 x draw, finished and crimped in a steamed stuffer-box crimper prior to being stored wet in a sealed container.</p> |
