| 摘要 |
1432285 Copolyimide filaments UPJOHN CO 30 Aug 1974 [12 Oct 1973] 38049/74 Addition to 1354926 Heading B5B [Also in Division C3] A filament comprises a copolyimide having the recurring unit where in 10 to 30% of the units R is and in the remainder R is The preparation of such polymers is described in Specification 1,354,926 and solutions thereof in polar solvents in Specification 1,354,927. The filaments may be prepared by spinning a solution of the polymer into a coagulant bath, passing the filament through at least one aqueous bath, and removing most of the volatile materials by passing it over at least one heated roller while drawing it, e.g. at 100‹ to 220‹ C., with a draw ratio of 1 x to 3 x . The filament may then be oriented, e.g. by drawing it over a surface heated at 325‹ to 400‹ C. to a draw ratio up to 5 x and subsequently tempered. Numerous suitable solvents, coagulants and surfactants are specified and the spinning procedure is exemplified in detail. The effect of choice of coagulant or cross-section is described, the use of glycerine or a glycol giving a "pseudo hollow" structure, Fig. 3, leading to advantageous high bulk properties. |
