| 摘要 |
1281942 Polyacrylonitrile fibres MITSUBISHI RAYON CO Ltd 36949/69 Heading B5B [Also in Division D1] An acrylonitrile polymer or copolymer fibre having an outer layer insoluble in dimethyl formamide at 75‹ C. which layer comprises ridges of more than 0À2 Á height at intervals of 1À5 to 12 Á in the plane of the longitudinal axis of the fibre may be produced by treating the fibre with a denaturalizing agent, defined as a chemical agent which makes the outer layer of the fibre insoluble in dimethyl formamide at 75‹ C., immersing the treated fibre in a shrinking agent and heating the fibre thus treated. The denaturalizing agent may be an aqueous solution of alkali or alkaline earth metal hydroxides, sulphuric acid, hydroxylamine salts or hydrazine. The shrinking treatment comprises either (a) immersing the fibres in an inert (non-solvent) heating medium at above 130‹ C., (b) immersing the fibres in a glycol solution of organic carbamate below 70‹ C. and subsequently heating to above 70‹ C., (c) immersing the fibre in solution (b) at above 70‹ C., or (d) immersing the fibres in a glycol or aqueous solution of the organic carbonate at below 70‹ C. withdrawing the fibres from the solution and squeezing the fibres so that the solution remaining on the fibres is less than 200% of the weight of the fibres and heating the fibres to above 70‹ C. In example 10 a conjugate fibre of acrylonitrile copolymers is spun, drawn, crimped and then treated according to the invention, with a bleaching step between denaturalizing and shrinking. The ridges may resemble a tuck, the edges of which are at an angle of 75 to 105 degrees to the plane of the longitudinal axis of the fibre, said tucks running discontinuously around the fibre circumference. The cross-section of the protuberances may be asymmetrical through a plane through the top of each ridge so that the fibre exhibits a differential frictional effect along its axis i.e. the frictional force required to pull a filament from a parallel bundle is different in both directions along the longitudinal axis of the fibre. The fibres so produced have a hand closely resembling wool and superior anti-pilling properties to wool and show a multicolour effect when treated in a bath of mixed dyes. |
