Patent EA-004429-B1 (EA)
Title: High-strength polyester filaments with small shrinkage and process for molding thereof
Inventor: CZIOLLEK JOACHIM
IPC: D01D5/16
Filed: 2000-07-25
Abstract: 1. High strength polyester filaments with small shrinkage having a tear strength of >70 cN/tex consisting of alpha) a polyester comprising at least 85 mol % of poly(C2-C4-alkylene) terephthalate, beta) from 0.1 to 2.0% by weight of an incompatible, thermoplastic, amorphous, polymeric additive having a glass transition temperature in the range from 90 to 170 degree C., and gamma) from 0 to 5.0% by weight of further additives, where the sum of alpha), beta) and gamma) is equal to 100%, the ratio of the melt viscosity of the polymeric additive beta) to the melt viscosity of the polyester component alpha) is from 1:1 to 7:1, and the polymeric additive beta) is present in the yarn in the form of fibrils having a mean diameter of <=80 nm which are distributed in the polyester component alpha). 2. High-strength polyester filaments with small shrinkage according to claim 1, wherein the ratio of the melt viscosities is from 1.5:1 to 5:1. 3. High-strength polyester filaments with small shrinkage according to claim 1 wherein the polymeric additive beta) is a copolymer which comprises the following monomer units: A=acrylic acid, methacrylic acid or CH2= CR-COOR, where R is an H atom or a CH3 group, and R' is a C1-15 -alkyl radical or a C5-12 -cycloalkyl radical or a C6-14 -alkyl radical, B=styrene or C1-3 -alkyl-substituted styrenes, where the copolymer consists of from 60 to 98% by weight of A and from 2 to 40% by weight of B. 4. High-strength polyester filaments with small shrinkage according to claim 3, wherein the copolymer consists of from 83 to 98% by weight of A and from 2 to 17% by weight of B. (amount = 100% by weight). 5. High-strength polyester filaments according to claim 3 wherein the copolymer consists of from 90 to 98% by weight of A and from 2 to 10% by weight of B. (amount = 100% by weight). 6. High-strength polyester filaments with small shrinkage according to claim 1 wherein the polymeric additive beta) is a copolymer which comprises the following monomer units: C=styrene or C1-3 -alkyl-substituted styrenes, D=one of more monomers of the formula I, II or III where R1, R2 and R3 are each an H atom or a C1-15- alkyl radical or a C5-12 -cycloalkyl radical or a C6-14- aryl radical, and where the copolymer consists of from 15 to 95% by weight of C and from 5 to 85% by weight of D, where the sum of C and D together gives 100% 7. High-strength polyester filaments with small shrinkage according to claim 6, wherein the copolymer consists of from 50 to 90% by weight of C and from 10 to 50% by weight of D, where the sum of C and D together gives 100%. 8. High-strength polyester filaments with small shrinkage according to claim 7, wherein the copolymer consists of from 70 to 85% by weight of C and from 15 to 30% by weight of D, where the sum of C and D together gives 100%. 9. High-strength polyester filaments with small shrinkage according to claim 1 wherein the copolymer additive beta) is a copolymer which comprises the following monomer units: E=acrylic acid, methacrylic acid or CH2=CR-COOR', where R is an H atom or a CH3 group, and R.' is a C1-15 -alkyl radical or a C5-12 -cycloalkyl radical or a C6-14 -aryl radical. F=styrene or C1-3 -alkly-substituted styrenes, G=one of more monomers of the formula I, II or III where R1, R2 and R3 are each an H atom or a C1-15-alkyl radical or a C5-12 -cycloalkyl radical or a C6-14 -aryl radical, H=one or more ethylenically unsaturated monomers which can be copolymerized with E and/or with F and/or G, from the group consisting of alpha-methylstyrene, vinyl acetate, acrylates and methacrylates which are different from E, vinyl chloride, vinylidene chloride, halogen-substituted styrenes, vinyl esters, isopropenyl ethers and dienes, where the copolymer consists of from 30 to 99% by weight of E, from 0 to 50% by weight of F, from >0 to 50% by weight of G and from 0 to 50% by weight of H, where the sum of E, F, G and H together gives 100%. 10. High-strength polyester filaments with small shrinkage according to claim 9, wherein the copolymer consists of from 45 to 97% by weight of E, from 0 to 30% by weight of F, from 3 to 40% by weight of G and from 0 to 30% by weight of H, where the sum of E, F, G and H together gives 100%. 11. High-strength polyester filaments with small shrinkage according to claim 10, wherein the copolymer consists of from 60 to 94% by weight of E, from 0 to 20% by weight of F, from 6 to 30% by weight of G and from 0 to 20% by weight of H, where the sum of E, F, G and H together gives 100%. 12. Process stretch molding of filaments of claim 1, wherein a) a polyester alpha) which comprises at least 85% mol % of poly-(C2-4-alklylene)therephthalate and from 0.1 to 2.0% by weight of an incompatible, thermoplastic, amorphous, polymeric additive beta) which has a glass transition temperature in the range from 90 to 170 degree C, where the ratio of the melt viscosity of the polymeric additive beta) to the melt viscosity of the polyester component alpha) is from 1:1 to 7:1, where these may comprise from 0 to 5.0% by weight of further 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 filaments, where the spinning take-off speed is from >700 to 1500 n/min; and c) the spun filaments from step b) are stretched, heat-set and wound up, where concentration of the additive polymer B in weight ratio % in polyester is defined as a function of given filament molding speed v in m/min and, desirable, double refraction of formed filaments deltan, according to following formula: x x f1 <= c <= x x f2 (1), wherein wherein deltan< deltano, deltan is double refraction of formed filament from polyester with additive polymer, according to invention, deltano is double refraction of formed filament from polyester obtained under the forming conditions but without additive polymer, x = 1 for additive polymers of type 1 or 3, according to claim 3 or 9, x = 2.8 for additive polymers of type 2 according to claim 6 (without acrylic compound). 13. Process stretch molding of filaments according to claim 12, characterized in that on step c) the relative stretching-out DR is defined as filament molding speed v in m/min and concentration of additive polymer in weight % according to the following formulas: f3 <= DR <= f4 (4), f3 = -5 x 10<-4> x v - 1.6 x 10<-4> x v x c/x + 0.98 x c/x + 3.55 (5), f4 = -5 x 10<-4> x v - 2.4 x 10<-4> x v x c/x + 1.46 x c/x + 3.55 (6). 14. Process stretch molding of filaments according to claim 13, characterized in that on step c) the spinning take-off speed is equal to product of filament molding speed v, relative stretching-out DR and relative relaxation.