Claims
- 1. A process for preparing spin-oriented polyester/polyamide biconstituent filaments (BC') that are of high boil-off shrinkage (S) and high shrinkage power (P.sub.s), involving first melt-spinning biconstituent filaments (AC') of low shrinkage (S) from a polyester polymer having a glass transition temperature (T.sub.g) of 40.degree. to 80.degree. C. and a zero-shear polymer melting point (T.sub.M.sup.o) of 240.degree. to 280.degree. C., and from a polyamide polymer, in an adjoining relationship, at a withdrawal speed in the range of 2 to 6 Km/min, and quenching said filaments (AC') to a temperature below said temperature (T.sub.g), followed by treating said filaments (AC') by rapidly heating to a treatment temperature above said temperature (T.sub.g) and up to [0.775(T.sub.M.sup.o +273)-273], and then immediately and rapidly cooling the filaments to below said temperature (T.sub.g), wherein said heating and cooling are carried out at rates sufficiently rapid to provide filaments (BC') characterized by:
- i) a residual draw-ratio (RDR) of 1.4 to 1.9, a post yield modulus (M.sub.py) of less than 12 g/dd, and high shrinkage (S) such that the value of (1-S/S.sub.m) is greater than 0.7, where RDR is (1+100/E.sub.B,%), E.sub.B being the elongation-to-break, and S.sub.m is [(6.5-RDR)/6.5].times.100%;
- ii) a high maximum shrinkage tension (ST.sub.max) of 0.1 g/d to 0.5 g/d at a peak shrinkage tension temperature T(ST.sub.max) between [0.65(T.sub.M.sup.o +273)-273] and [0.75(T.sub.M.sup.o +273)-273]; and
- iii) a shrinkage modulus (M.sub.s) of up to 5 g/d; and high shrinkage power (P.sub.s) of 1.5 to 12 (g/d)%;
- and wherein said filaments (AC') are characterized by:
- iv) a residual draw-ratio (RDR) between 1.4 and 1.9 and low shrinkage (S) such that the value of (1-S/S.sub.m) is at least 0.9; and
- v) a maximum shrinkage tension (ST.sub.max) less than 0.15 g/d at a peak shrinkage tension temperature T(ST.sub.max) less than [0.70(T.sub.M.sup.o +273)-273].
- 2. A process according to claim 1, comprising spinning said polymers into a symmetric sheath/core biconstituent filament relationship, with a sheath of nylon 66 polyamide and a core of poly(ethylene terephthalate) polyester, from melt at a polymer temperature (Tp) that is 20.degree. to 50.degree. C. above the melting point (T.sub.M.sup.o), and wherein the polyester and polyamide polymers are selected to have similar melt flow viscosities of the same order of magnitude at the polymer temperature (Tp).
- 3. A process for preparing symmetric sheath/core, respectively polyamide/polyester, biconstituent spin-oriented filaments involving melt-spinning such biconstituent filaments from a polyamide polymer and from a polyester polymer having a glass transition temperature (Tg) of 40.degree. to 80.degree. C., and a zero-shear polymer melting point (T.sub.M.sup.o) of 240.degree. to 280.degree. C., in a symmetric sheath/core adjoining relationship, from melt at a polymer temperature (Tp) that is 20.degree. to 50.degree. C. above the melting point (T.sub.M.sup.o), and wherein the polyester and polyamide polymers are selected to have similar melt flow viscosities of the same order of magnitude at the polymer temperature (Tp) at a withdrawal speed in the range of 2 to 6 Km/min, and quenching said filaments to a temperature below said temperature (T.sub.g), wherein the compositions of said polymers and the spinning and quenching conditions are so selected to provide both sheath and core elements having boil-off shrinkages that are approximately the same and between 3 and 30%, and to provide filaments characterized by:
- i) a residual draw ratio (RDR) of 1.4 to 1.9, an initial modulus (M.sub.i) greater than 20 g/d, and shrinkage (S) such that the value of (1-S/S.sub.m) is greater than 0.7, where RDR is (1+100,/E.sub.B,%). E.sub.B being the elongation-to-break;
- ii) a high maximum shrinkage tension (ST.sub.max) of 0.1 g/d to 0.5 g/d at a peak shrinkage tension temperature T(ST.sub.max) between [0.65(T.sub.M.sup.o +273)-273] and [0.75(T.sub.M.sup.o +273)-273]; and
- iii) a shrinkage modulus (M.sub.s) of up to 5 g/d; and high shrinkage power (P.sub.s) of 1.5 to 12 (g/d)%.
- 4. A process according to claim 1, comprising drawing the resulting biconstituent filaments at a temperature T.sub.D between [0.65(T.sub.M.sup.o +273)-273] and [0.725(T.sub.M.sup.o +273)-273 ] to a drawn residual draw ratio (RDR).sub.D between 1.2 and 1.4 under conditions selected to maintain T(ST.sub.max) in the range {0.65(TM.sup.o +273)-273} to {0.725(T.sub.M.sup.o +273)-273}, shrinkage modulus (M.sub.s) less than 5 g/d, and (1-S/S.sub.m) greater than 0.7; and to provide a maximum shrinkage tension (ST.sub.max) of 0.3 to 0.7 g/d, shrinkage power (P.sub.s) of 5 to 12 (g/d)% and post-yield modulus (Mpy) less than 12 g/dd.
- 5. A process according to claim 2, comprising drawing the resulting biconstituent filaments at a temperature T.sub.D between [0.65(T.sub.M.sup.o +273)-273] and [0.725(T.sub.M.sup.o +273)-273] to a drawn residual draw ratio (RDR).sub.D between 1.2 and 1.4 under conditions selected to maintain T(ST.sub.max) in the range {0.65(TM.sup.o +273)-273} to {0.725(T.sub.M.sup.o +273)-273}, shrinkage modulus (M.sub.s) less than 5 g/d, and (1-S/S.sub.m) greater than 0.7; and to provide a maximum shrinkage tension (ST.sub.max) of 0.3 to 0.7 g/d, shrinkage power (P.sub.s) of 5 to 12 (g/d)% and post-yield modulus (M.sub.py) less than 12 g/d.
- 6. A process according to claim 3, comprising drawing the resulting biconstituent filaments at a temperature T.sub.D between [0.65(T.sub.M.sup.o +273)-273] and [0.725(T.sub.M.sup.o +273)-273] to a drawn residual draw ratio (RDR).sub.D between 1.2 and 1.4 under conditions selected to maintain T(ST.sub.max) in the range {0.65(TM.sup.o +273)-273} to {0.725(TM.sup.o +273)-273}, shrinkage modulus (M.sub.s) less than 5 g/d, and (1-S/S.sub.m) greater than 0.7; and to provide a maximum shrinkage tension (ST.sub.max) of 0.3 to 0.7 g/d, shrinkage power (P.sub.s) of 5 to 12 (g/d)% and post-yield modulus (M.sub.py) less than 12 g/dd.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a division of U.S. application Ser. No. 08/085,266, filed Jun. 29, 1993, and now U.S. Pat. No. 5,384,082, which is a continuation-in-part of U.S. application Ser. No. 07/786,585, filed by Frankfort et al., Nov. 1, 1991, now U.S. Pat. No. 5,223,198, and of the following two applications, that were also filed Nov. 1, 1991, 07/786,582, filed by Hendrix et al., now U.S. Pat. Nos. 5,244,616, and 07/786,584, filed by Boles et al., now U.S. Pat. No. 5,223,197, and of U.S. application No. 08/035,988, filed by Boles et al., Mar. 23, 1993, now U.S. Pat. No. 5,364,701 and of the following two U.S. application Nos. 07/753,529 and 07/753,769, both filed by Knox et al., Sep. 3, 1991, and now U.S. Pat. Nos. 5,229,060 and 5,261,472, all filed as continuations-in-part (directly or indirectly) of U.S. application No. 07/338,251, filed Apr. 14, 1989 now U.S. Pat. No. 5,066,447, sometimes referred to herein as the "parent application", but also itself a continuation-in-part application of abandoned U.S. application No. 07/053,309, filed May 22, 1987, as a continuation-in-part of abandoned U.S. application No. 824,363, filed Jan. 30, 1986; and is also a continuation-in-part of U.S. applications Nos. 08/005,672 and 08/015,733 (now U.S. Pat. Nos. 5,228,553 and 5,250,245) both filed by Collins et al, on Jan. 19 and Feb. 10, 1993 respectively, as continuations-in part of abandoned U.S. application Nos. 07/647,381, filed Jan. 29, 1991, and 07/860,766, filed Mar. 27, 1992, as continuation-in-part of abandoned U.S. application No. 07/647,371, also filed Jan. 29, 1991.
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Related Publications (13)
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Nov 1991 |
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786584 |
Nov 1991 |
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Mar 1993 |
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753529 |
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753769 |
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5672 |
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15733 |
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786582 |
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Divisions (1)
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85266 |
Jun 1993 |
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Continuation in Parts (6)
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786586 |
Nov 1991 |
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860766 |
Mar 1992 |
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338251 |
Apr 1989 |
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53309 |
May 1987 |
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824363 |
Jan 1986 |
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647381 |
Jan 1991 |
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