| 摘要 |
1324781 Film fibrillation UNION CARBIDE CORP 8 June 1970 [9 June 1969] 27693/70 Heading B5B [Also in Divisions C3 and D1] Non-woven ultra-fine fibrous webs composed of a synthetic polymer blend are produced, using the means shown in Fig. 1, by passing a tape, formed from the polymer blend by melt-extrusion and oriented mono-axially, into a trough 5 which is sprayed from nozzles 7 with caustic soda solution and then, if desired, pulled gently to increase its width, after which the tape (or sheet) is washed and passed on to an endless belt to effect drying. Fig. 2 illustrates an alternative means for treating the tape with caustic soda. The caustic soda removes component (a) of the polymer blend and thereby yields a web of ultrafine fibres, said polymer blend being composed of (a) 30-60% by weight of a copolymer of ethylene and acrylic and/or methacrylic acid (or a water-soluble or water-dispersible salt of such acid), which copolymer contains at least 14% by weight of the acid component, (b) a meltextrudable fibre-forming polymer which is not extractable by water and which is incompatible with the copolymer (a) in the molten state, and (c) up to 20% by weight of an organic compound which has a hygroscopicity at least equal to that of the copolymer (a), is melt-immiscible and non- reactive with the polymer (b), and has a boiling point greater than the temperature obtained during melt extrusion of the blend. Component (b) may be a vinyl, acrylic or condensation polymer, e.g. polyethylene or polypropylene and component (c) is preferably an alcohol or ether, e.g. glycerine. |
