Patent GB-1167390-A (GB)
Title: Two-Component Conjugate Filament and a method of producing said Filament
IPC: D01F8/12
Filed: 1967-12-28
Abstract: 1,167,390. Conjugate filaments. KANEGAFUCHI BOSEKI K.K., and SNIA VISCOSA SOC. NAZIONALE INDUSTRIA APPLICAZIONI VISCOSA S.p.A. 28 Dec., 1967 [28 Dec., 1966], No. 58768/67. Heading B5B. [Also in Division A3] A two-component conjugate filament has an unbiased dyeability and a suppressed crimpability in which three distinctly sectioned portions X, Y and Z including respectively a part of the periphery of the unitary filament are disposed in a side-by-side relation and extend uniformly through the entire length of the filament, two portions X and Z of said three portions being separated by an adherent intervening portion Y therebetween, said separated portions being composed of one thermoplastic synthetic linear polymer A and said intervening portion being composed of another thermoplastic synthetic linear polymer B which has a different heat shrinkability from that of the other polymer, in which the two crimp developing forces which are caused respectively by the differences in the shrinkability between said intervening portion and each of said separated portions do not substantially cancel each other out and the crosssectional surface area of the intervening portion is from <SP>2</SP>/ 5 ths to <SP>3</SP>/ 5 ths of the total cross-sectional surface area of the filament. Such filaments are shown in cross-section in Figs. 2 to 4. As in Fig. 3, the relation between the angle # made by two straight lines OS, OT which pass through the centre of gravity of the cross-sectional figure of the filament and bisect each of the cross-sectional areas of said two separated portions and the ratio x of the cross-sectional areas of said separated portions may satisfy the formula: x##<SP>8</SP>/ 9  #, where # does not exceed # radians and x is a proper fraction. Preferably, the surface area of said intervening portion is substantially one half of the total surface area of the filament, and to provide the filament with an unbiased dyeability, the total length of the periphery occupied by portions X and Z should be substantially equal to that occupied by portion Y. To this end, <SP>2</SP>/ 5 ths to <SP>3</SP>/ 5 ths of the peripheral length of the cross-section should be occupied by the intervening portion Y, so that the ratio of the sum of the surface areas formed by component A to that formed by component B should be within a range of <SP>3</SP>/ 2  to <SP>2</SP>/ 3 rds., the most preferred such ratio being about 1/1. The cross-sectional areas of portions X and Z may be equal, as shown in Fig. 3, or different, as shown in Figs. 2 and 4. As shown in Fig. 3, the angle made by two straight lines OS, OT which pass through the centre of gravity of the crosssectional figure of the filament and bisect each of the cross-sectional areas of the separated portions may be other than # radians, and is preferably from #/3 radians to <SP>8</SP>/ 9 ths radians, and especially from <SP>4</SP>/ 9 ths # radians to <SP>7</SP>/ 9 ths # radians. As shown in Fig. 2, the angle made by two straight lines OS, OT passing through the centre of gravity of the cross-sectional figure of the filament and bisecting each of the crosssectional areas of the separated portions may be substantially # radians and the cross-sections of the two separated portions are of substantially unequal area, the ratio of the cross-sectional areas of the two separated portions being suitably <SP>1</SP>/ 20 th to <SP>8</SP>/ 9 ths, and especially from <SP>1</SP>/ 5 th to ¢. Specified thermoplastic synthetic linear polymers include polyamides, polyesters, polyetheresters, polyolefins, polycarbonates, polyoxymethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, copolymers and mixtures thereof, and especially preferred are polyamides selected from nylon-6, nylon-7, nylon-9, nylon-11, nylon-12, nylon-66, nylon-610, polymetaxylylene adipamide, polyparaxylylene adipamide, copolyamides obtained from two or more of such polyamide-forming substances as e.g. #-caprolactam, nylon-66 salt, nylon-610 salt, nylon-12 salt, metaxylylene diammonium adipate, paraxylylene diammonium adipate, hexamethylene diammonium terephthalate, and hexamethylene diammonium isophthalate. Such filaments are made by feeding a first molten thermoplastic synthetic linear polymer B through a main channel 7 (Figs. 5 and 6) and feeding a second molten thermoplastic synthetic linear polymer A through two sub-channels 8, 9 connecting to the said main channel, so that both the polymers A and B are adhered and then extruded simultaneously from an orifice 10, polymers A and B being fed and extruded in such volume ratios that the angle # in radians made by the projection of the axes of the two sub-channels on a plane perpendicular to an axis of the main channel and the ratio x of the cross-sectional areas of the portions formed by the polymer A satisfies the formula: x##<SP>8</SP>/ 9  #, provided # does not exceed # radians and x is a proper fraction, and that the surface area formed by polymer B is between <SP>2</SP>/ 5 ths and <SP>3</SP>/ 5 ths of the total surface area of the filament. x may be substantially 1, or from <SP>1</SP>/ 20 th to <SP>8</SP>/ 9 ths, especially from <SP>1</SP>/ 5 th to ¢. # may be other than # radians, especially from #/3 to <SP>8</SP>/ 9 ths # radians, and particularly from <SP>4</SP>/ 9 ths # to <SP>7</SP>/ 9 ths # radians. The surface area formed of polymer B may be substantially ¢ of the total surface area of the filament. Examples describe the spinning of a copolymer of 90 parts by weight of nylon-6 and 10 parts by weight of polyhexamethylene isophthalamide, as component A, component B being nylon-6.