Patent EA-004441-B1 (EA)
Title: High-strength polyester threads and methods for producing the same
Inventor: CZIOLLEK JOACHIM
IPC: D01D5/16
Filed: 2000-07-25
Abstract: 1. High-strength polyester threads with thread tension ( 70 cN/tex, characterized in that they consist of alpha) polyester, which comprises, at least, 85 mol % of poly(C2-C4-alkylen) terephthalate, beta) from 0.1 to 2.0 wt % of an incompatible, thermoplastically processable amorphous polymer additive with a glass transition temperature of 90 to 170 degree C and gamma) 0 to 5.0 wt % usual additives, wherein the sum of alpha), beta) and gamma) is 100%, a ratio of melt viscosity of the adding polymer beta) to the melt viscosity of the polyester component alpha) of 1:1 to 7:1 and the adding polymer beta)is present in fibres in the form of fibrils distributed in the polyester component alpha) with an average diameter <= 80 nm. 2. The high-strength polyester threads according to claim 1, characterized in that a ratio of the melt viscosity is from 1.5:1 to 5:1. 3. The high-strength polyester threads according to claim 1 and 2, characterized in that the adding polymer beta) is a copolymer, which comprises the following monomer units: A ( acrylic acid, methacrylic acid or CH2 ( CR -COOR', wherein R' is a C1-15-alkyl radical, or C5-12-cycloalkyl radical, or C6-14-aryl radical and B ( styrene or C1-3-alkyl-substituted styrene, wherein copolymer comprises from 60 to 98 wt % of A and from 2 to 40 wt % of B (the sum ( 100 wt %). 4. The high-strength polyester threads according to claim 3, characterized in that the copolymer comprises from 83 to 98 wt % of A and from 2 to 17 wt % of B (the sum ( 100 wt %). 5. The high-strength polyester threads according to claim 3 or 4, characterized in that the copolymer comprises from 90 to 98 wt % of A and from 2 to 10 wt % of B (the sum ( 100 wt %). 6. The high-strength polyester threads according to claim 1 and 2, characterized in that the adding polymer beta) is a copolymer, which comprises the following monomer units: C ( styrene or C1-3-alkyl-substituted styrene, D ( one or several monomers of formulae I, II or III wherein R1, R2 or R3 are each H-atom or C1-15-alkyl radical or C5-12- cycloalkyl radical, or C6-14-aryl radical, wherein the copolymer consists from 15 to 95 wt % of C and from 5 to 85 wt % of D, wherein C and D sum is 100%. 7. The high-strength polyester threads according to claim 6, characterized in that the copolymer consists from 50 to 90 wt % of C and from 10 to 50 wt % of D, wherein C and D sum is 100%. 8. The high-strength polyester threads according to claim 6 or 7, characterized in that the copolymer consists from 70 to 85 wt % of C and from 30 to 15 wt % of D C and D sum is 100%. 9. The high-strength polyester threads according to claim 1 and 2, characterized in that the adding polymer beta) is a copolymer, which comprises the following monomer units: E ( acrylic acid, methacrylic acid or CH2 ( CR -COOR', wherein R' is a C1-15-alkyl radical, or C5-12-cycloalkyl radical, or C6-14-aryl radical and F ( styrene or C1-3-alkyl-substituted styrene, G( one or several monomers of formulae I, II or III wherein R1, R2 or R3 are each H-atom or C1-15-alkyl radical or C5-12- cycloalkyl radical, or C6-14-aryl radical, H ( one or several unsaturated monomers, which can be copolymerized with E and/or with F, and/or with G, from the group consisting of alpha- methystyrene vynylacetate, acrylic acid ethers, methacryl acid ethers, which differ from E, vynylchloride, vynyllidenchloride, halo-substituted styrene, vynyl ethers, isopropenyl ethers and dienes. 10. The high-strength polyester threads according to claim 9, characterized in that the copolymer consists from 45 to 97 wt % of E and from 0 to 30 wt % of F, from 3 to 40 wt % of G and from 0 to 30 wt % of H, wherein E, F, G and H sum is 100%. 11. The high-strength polyester threads according to claim 9 or 10, characterized in that the copolymer consists from 60 to 94 wt % of E and from 0 to 20 wt % of F, from 6 to 30 wt % of G and from 0 to 20 wt % of H, wherein E, F, G and H sum is 100%. 12. A method for producing high-strength polyester threads according to claims 1-11, characterized in that a) polyester alpha), which comprises, at least, 85 mol % of poly(C2-C4-alkylen) terephthalate, and from 0.1 to 2.0 wt % of an incompatible, thermoplastically processable amorphous polymer additive beta) with a glass transition temperature of 90 to 170 degree C, a ratio of melt viscosity of the adding polymer beta) to the melt viscosity of the polyester component alpha) of 1:1 to 7:1, wherein they may comprise from 0 to 5.0 wt % of usual additives gamma), are mixed in the molten state in a static mixer with shearing, where the shear rate is from 16 to 128 sec<-1>, and the product of the shear rate and the residence time in the mixer in seconds to the power 0.8 is set to a value of at least 250; b) the melt mixture from step a) is spun to give spun threads, where the spinning take-off speed is from >700 to 1500 n/min; and c) the spun threads from step b) are stretched, heat-set and wound up, where the stretching ratio is at least 1:5. 13. A method for the production of high-strength polyester threads according to claim 12, wherein the spinning take-off speed is from 750 to 100 m/min. 14. Process for the production of high-strength polyester threads according to claim 13, wherein the concentration C of the polymeric additive is selected in the range of 0.1 to 2.0% by weight in such a way that the birefringence of the spun threads is < 3.5 X 10<-3>.