Preparing method of high-modulus-low-shrinkage activated PET industrial yarn

Abstract

A type of high-modulus-low-shrinkage activated PET industrial yarn and preparing method thereof are disclosed. The preparing method is to manufacture filament from a modified polyester, which is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol and tert-butyl branched heptanediol, through a series of processes composed of viscosity enhancing by solid state polycondensation, melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling with activation oil, winding and pre-activation treatment. The relaxation heat-treating indicates passing the modified polyester yarns through a space with a certain temperature within 200-220° C. under a proper relaxation state; and the proper relaxation state means a 3.0-5.0% of overfeed for the winding. The improvement of activator efficiency by importing the tert-butyl branched diol into the polyester, together with the synergistic effect of heat setting temperature and high winding overfeed rate, will reduce the fiber thermal shrinkage.

Claims

1. A preparing method for a high-modulus-low-shrinkage activated Polyethylene terephthalate (PET) industrial yarn, comprising manufacturing a filament from a modified polyester through a series of processes comprising composed of viscosity enhancing by solid state polycondensation, melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling with activation oil, winding and pre-activation treatment; wherein the modified polyester before the viscosity enhancing by the solid state polycondensation is a product of esterification and successive polycondensation reactions of an evenly mixed mixture of terephthalic acid, ethylene glycol and tert-butyl branched heptanediol, wherein the tert-butyl branched heptanediol has a molecular formula of ##STR00004## with R standing for —H, —CH.sub.2CH.sub.3 or —C(CH.sub.3).sub.3; wherein the relaxation heat-treating indicates passing modified polyester yarns through a space with a certain temperature under a proper relaxation state; wherein the proper relaxation state is a 3.0-5.0% of overfeed for the winding; and the certain temperature is within a range of 200-220° C.

2. The preparing method of claim 1, wherein the high-modulus-low-shrinkage activated Polyethylene terephthalate (PET) industrial yarn has the following performance indices: a fineness of 930-1670 dtex, a breaking strength ≥7.8 cN/dtex, a deviation rate of linear density of ±1.2%, a breaking strength CV value ≤2.5%, an elongation at break of 11.0-13.5%, an deviation rate of elongation of ±1.5%, an elongation at break CV value ≤8.0%, an elongation at 4.0 cN/dtex load of 6.0-7.0%, a deviation rate of elongation at 4.0 cN/dtex load of ±0.8%, an interlacing degree of 6±2-3/m.

3. The preparing method of claim 2, wherein the high-modulus-low-shrinkage activated PET industrial yarn has a dry heat shrinkage of 2.5±0.5% tested under a condition of 177° C.×10 min×0.05 cN/dtex, and shows a static adhesion of 49-53 N or 55-62 N to a vulcanized rubber, wherein the static adhesion is determined through H-pull method when the high-modulus-low-shrinkage activated Polyethylene terephthalate (PET) industrial yarn is made into a cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F.

4. The preparing method of claim 1, wherein the space with the certain temperature indicates a room formed by a pair of parallel hot plates located between the last set of heat setting rollers and winding roller; wherein the parallel hot plates are aligned in both sides and have a length of 3.0-4.0 m along a passing direction of the filament; wherein the filament passes through a center of the parallel hot plates and keep a distance of 5-10 mm from the both sides, wherein the parallel hot plates are 300-400 mm from the winding roller and 200-300 mm from the last set of the heat setting rollers.

5. The preparing method of claim 1, wherein the tert-butyl branched heptanediol is synthesized by means of: (1) mixing isobutanol and a 40-50% KOH aqueous solution with a molar ratio of the isobutanol to the KOH as (5-6):1, then carrying out a first reaction with stirring at 100-110° C. for 4-5 hr to obtain potassium isobutanol in a first reaction mixture; (2) removing impurities from the first reaction mixture in step (1), then adding in xylene to the potassium isobutanol to form a second reaction mixture with a molar ratio of the potassium isobutanol to the xylene as (1.3-1.5):(2.0-3.0) and cooling the second reaction mixture to 0-5° C.; (3) adding 3-methyl-3-hydroxybutyne and M into the second reaction mixture of step (2) with a molar ratio of 3-methyl-3-hydroxybutyne:M:xylene as 1:(1.2-1.3):(2.0-3.0), then starting a second reaction at 25-35° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying; (4) mixing the octyne diol, ethanol and a Pd catalyst with a weight ratio of (2-3):10:(0.01-0.03) and then carrying out a third reaction accompanied by a continuous hydrogen input at 40-50° C. for 50-60 min, and finally obtaining the tert-butyl branched heptanediol through a series of processes of separation and purification; wherein M is 2,2-dimethylpropionaldehyde, 2,2-dimethyl-3-pentanone, 2,2,4-trimethyl-3-pentanone or 2,2,4,4-tetramethyl-3-pentanone when R═—H, —CH.sub.2CH.sub.3, —CH(CH.sub.3).sub.2 or —C(CH.sub.3).sub.3 in the molecular formula, respectively.

6. The preparing method of claim 5, wherein the modified polyester is manufactured through following steps: (1) Esterification concocting the terephthalic acid, the ethylene glycol and the tert-butyl branched heptanediol into a slurry, then adding in a catalyst, a matting agent and a stabilizer, and carrying out the esterification in a nitrogen atmosphere with a pressure of normal value-0.3 MPa at 250-260° C., finally ending the esterification when water distillation reaches more than 90% of a theoretical value; (2) Polycondensation for products of the esterification, smoothly reducing the pressure to less than 500 Pa within 30-50 min and carrying out the polycondensation at 250-260° C. for 30-50 min, successively, further reducing the pressure to less than 100 Pa and continuing the polycondensation at 270-282° C. for 50-90 min.

7. The preparing method of claim 6, wherein a molar ratio of the terephthalic acid, the ethylene glycol and the tert-butyl branched heptanediol is 1:(1.2-2.0):(0.03-0.05), and additions of the catalyst, the matting agent and the stabilizer are respectively 0.03-0.05 wt %, 0.20-0.25 wt % and 0.01-0.05 wt % of an amount of the terephthalic acid.

8. The preparing method of claim 7, wherein the catalyst is one of antimony trioxide, antimony glycol or antimony acetate; the matting agent is titanium dioxide; and the stabilizer is one of triphenyl phosphate, trimethyl phosphate or trimethyl phosphite.

9. The preparing method claim 8, wherein the modified polyester has a molecular weight of 25000-30000 Da and a molecular weight distribution index of 1.8-2.2 prior to the viscosity enhancing by the solid state polycondensation, and after has an intrinsic viscosity of 1.0-1.2 dL/g.

10. The preparing method of claim 1, wherein spinning process involves technological parameters of 295-315° C. for an extruder temperature, 295-300° C. for a spin head temperature, 175±5 bar for a spin head pressure, 23±2° C. for a cross air temperature, 75±5% for a cross air humidity, 0.5-0.6±0.05 m/s for a cross air blow speed, 0.4-0.5 wt % for an oiling rate of activation oil agent, 0.16±0.02 MPa for a pre-interlacing pressure, 0.22±0.02 MPa for an interlacing pressure, 2630-3300 m/min for a winding speed, 70˜75° C. for a pre-activation treatment temperature and 15-20 hr for a pre-activation treatment time; and wherein the stretching and heat setting involve technological parameters of 500-600 m/min for a roller 1 speed, 520-1000 m/min for a roller 2 speed, 80-100° C. for a roller 2 temperature, 1800-2500 m/min for a roller 3 speed, 100-150° C. for a roller 3 temperature, 2800-3500 m/min for a roller 4 speed, 200-250° C. for a roller 4 temperature, 2800-3500 m/min for a roller 5 speed, 200-250° C. for a roller 5 temperature, 2720-3410 m/min for a roller 6 speed, 150-200° C. for a roller 6 temperature.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Based on above mentioned method, the following embodiments are carried out for further demonstration in the present invention. It is to be understood that these embodiments are only intended to illustrate the invention and are not intended to limit the scope of the invention. In addition, it should be understood that after reading the contents described in the present invention, those technical personnel in this field can make various changes or modifications to the invention, and these equivalent forms also fall within the scope of the claims attached to the application.

(2) ##STR00003##

Example 1

(3) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(4) (1) Preparation of modified polyester

(5) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(6) (a) mixing isobutanol and 43% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5:1, then carrying out the reaction with a stirring at 100° C. for 4 hr to obtain potassium isobutanol;

(7) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.3:2.2 and cooling the system to 1° C.;

(8) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.2:2.2, then starting the reaction at 25° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(9) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 2.2:10:0.01 and then carrying out the reaction accompanied with a continuous hydrogen input at 50° C. for 50 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(10) (1.3) Esterification

(11) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.2:0.05 into a slurry, then adding in antimony trioxide, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of normal value at 250° C., finally ending the reaction when the water distillation reaching 90% of the theoretical value, wherein the additions of antimony trioxide, titanium dioxide and triphenyl phosphate being 0.03 wt %, 0.25 wt % and 0.01 wt % relative to the amount of terephthalic acid, respectively;

(12) (1.3) Polycondensation

(13) for the esterification products, smoothly reducing the pressure to 500 Pa (absolute value) within 30 min and carrying out reaction at 250° C. for 30 min, successively, further reducing the pressure to 100 Pa (absolute value) and continuing the reaction at 270° C. for 50 min, and finally obtaining a modified polyester with a molecular weight of 30000 Da and a molecular weight distribution index of 1.8;

(14) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.0 dL/g through the solid state polycondensation;

(15) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(16) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 4.9%, through the space formed by a pair of parallel hot plates (200° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.0 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 5 mm from both sides, therein the hot plates are 300 mm from the winding roller and 200 mm from the last set of heat setting rollers.

(17) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(18) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 930 dtex, breaking strength 7.8 cN/dtex, deviation rate of linear density −1.2%, breaking strength CV value 2.5%, elongation at break 11.0%, deviation rate of elongation ±1.5%, elongation at break CV value 8.0%, elongation at 4.0 cN/dtex load 6.0%, deviation rate of elongation at 4.0 cN/dtex load −0.8%, interlacing degree 3/m, dry heat shrinkage 2.0% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 49 N or 55 N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(19) Comparison 1

(20) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn involved steps basically the same as those in Example1, except for no relaxation heat setting, winding speed being 2680 m/min, wind overfeeding rate being 1.47% and without using 2,6,6-trimethyl-2,5-heptanediol when preparing the polyester, from which the finally obtained high-modulus-low-shrinkage activated PET industrial yarn possesses the mechanical performance indices of fineness 913 dtex, breaking strength 7.65 cN/dtex, deviation rate of linear density −1.1%, breaking strength CV value 2.5%, elongation at break 12.7%, deviation rate of elongation 1.5%, elongation at break CV value 8.0%, elongation at 4.0 cN/dtex load 6.8%, deviation rate of elongation at 4.0 cN/dtex load −0.8%, interlacing degree 3/m, dry heat shrinkage 3.2% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 46 N or 52N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(21) Comparison 2

(22) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn involved steps basically the same as those in Example1, except for no relaxation heat setting, winding speed being 2680 m/min, and wind overfeeding rate being 1.47%, from which the finally obtained high-modulus-low-shrinkage activated PET industrial yarn possesses the mechanical performance indices of fineness 913 dtex, breaking strength 7.68 cN/dtex, deviation rate of linear density −1.1%, breaking strength CV value 2.5%, elongation at break 12.5%, deviation rate of elongation ±1.5%, elongation at break CV value 8.0%, elongation at 4.0 cN/dtex load 6.9%, deviation rate of elongation at 4.0 cN/dtex load −0.8%, interlacing degree 3/m, dry heat shrinkage 3.2% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 49N or 55N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(23) Comparison 3

(24) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn involved steps basically the same as those in Example1, except for not using 2,6,6-trimethyl-2,5-heptanediol when preparing the polyester, from which the finally obtained high-modulus-low-shrinkage activated PET industrial yarn possesses the mechanical performance indices of fineness 930 dtex, breaking strength 7.78 cN/dtex, deviation rate of linear density −1.1%, breaking strength CV value 2.5%, elongation at break 10.8%, deviation rate of elongation ±1.5%, elongation at break CV value 8.0%, elongation at 4.0 cN/dtex load 6.1%, deviation rate of elongation at 4.0 cN/dtex load −0.8%, interlacing degree 3/m, dry heat shrinkage 2.1% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 46N or 52N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(25) From the data analysis on the Example 1 and Comparison 1-3, it can be concluded that the incorporation of 2,6,6-trimethyl-2,5-heptanediol in the present invention could improve the efficiency of the activator agent so as to promote the activation performance of PET industrial yarn, whereas the relaxation heat setting could significantly reduce the heat shrinkage rate of the PET industrial yarn.

(26) Comparison 4

(27) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn involved steps basically the same as those in Example1, except for using 1,2-dodecyl glycol instead of 2,6,6-trimethyl-2,5-heptanediol when preparing the polyester, from which the finally obtained high-modulus-low-shrinkage activated PET industrial yarn possesses the mechanical performance indices of fineness 930 dtex, breaking strength 7.77 cN/dtex, deviation rate of linear density −1.1%, breaking strength CV value 2.5%, elongation at break 10.8%, deviation rate of elongation ±1.5%, elongation at break CV value 8.0%, elongation at 4.0 cN/dtex load 6.0%, deviation rate of elongation at 4.0 cN/dtex load −0.8%, interlacing degree 3/m, dry heat shrinkage 2.1% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 46N or 52N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(28) From the data analysis on the Example 1 and Comparison 1-3, it can be concluded that the tere-butyl branched diol, compared with 1,2-dodecyl glycol containing long alkyl chain, is more beneficial to the activation of PET fibers, and the reason on one hand is that the short side chain can enlarge the void free volume whereas the long side can mainly enlarge the slit free volume, and the void free volume is more efficient than the slit one for the penetration of activator agents into the fiber, on the other hand, the short side chain with higher rigidity will seldom cause the molecular chain entanglement and gain more free volume in the molecular aggregate.

Example 2

(29) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(30) (1) Preparation of modified polyester

(31) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(32) (a) mixing isobutanol and 40% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5.5:1, then carrying out the reaction with a stirring at 100° C. for 5 hr to obtain potassium isobutanol;

(33) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.3:2.0 and cooling the system to 3° C.;

(34) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.3:2.5, then starting the reaction at 30° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(35) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 2.5:10:0.01 and then carrying out the reaction accompanied with a continuous hydrogen input at 50° C. for 55 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(36) (1.3) Esterification

(37) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.3:0.04 into a slurry, then adding in antimony trioxide, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.15 MPa at 252° C., finally ending the reaction when the water distillation reaching 91% of the theoretical value, wherein the additions of antimony trioxide, titanium dioxide and triphenyl phosphate being 0.035 wt %, 0.22 wt % and 0.015 wt % relative to the amount of terephthalic acid, respectively;

(38) (1.3) Polycondensation

(39) for the esterification products, smoothly reducing the pressure to 498 Pa (absolute value) within 32 min and carrying out reaction at 252° C. for 32 min, successively, further reducing the pressure to 99 Pa (absolute value) and continuing the reaction at 272° C. for 55 min, and finally obtaining a modified polyester with a molecular weight of 30500 Da and a molecular weight distribution index of 1.85;

(40) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.05 dL/g through the solid state polycondensation;

(41) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(42) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 4.2%, through the space formed by a pair of parallel hot plates (202° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.2 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 6 mm from both sides, therein the hot plates are 311 mm from the winding roller and 220 mm from the last set of heat setting rollers.

(43) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(44) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1070 dtex, breaking strength 8.0 cN/dtex, deviation rate of linear density −1.0%, breaking strength CV value 2.1%, elongation at break 12.5%, deviation rate of elongation −1.2%, elongation at break CV value 7.5%, elongation at 4.0 cN/dtex load 6.2%, deviation rate of elongation at 4.0 cN/dtex load −0.6%, interlacing degree 6/m, dry heat shrinkage 2.2% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 50N or 57N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

Example 3

(45) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(46) (1) Preparation of modified polyester

(47) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(48) (a) mixing isobutanol and 48% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5:1, then carrying out the reaction with a stirring at 105° C. for 4.5 hr to obtain potassium isobutanol;

(49) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.5:2.5 and cooling the system to 0° C.;

(50) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.25:2.0, then starting the reaction at 30° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(51) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 2:10:0.02 and then carrying out the reaction accompanied with a continuous hydrogen input at 42° C. for 60 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(52) (1.3) Esterification

(53) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.4:0.035 into a slurry, then adding in antimony glycol, titanium dioxide and triphenyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.18 MPa at 253° C., finally ending the reaction when the water distillation reaching 92% of the theoretical value, wherein the additions of antimony glycol, titanium dioxide and triphenyl phosphate being 0.04 wt %, 0.23 wt % and 0.02 wt % relative to the amount of terephthalic acid, respectively;

(54) (1.3) Polycondensation

(55) for the esterification products, smoothly reducing the pressure to 497 Pa (absolute value) within 35 min and carrying out reaction at 253° C. for 35 min, successively, further reducing the pressure to 98 Pa (absolute value) and continuing the reaction at 274° C. for 62 min, and finally obtaining a modified polyester with a molecular weight of 32000 Da and a molecular weight distribution index of 1.9;

(56) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.08 dL/g through the solid state polycondensation;

(57) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(58) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 3.3%, through the space formed by a pair of parallel hot plates (210° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.3 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 7 mm from both sides, therein the hot plates are 335 mm from the winding roller and 235 mm from the last set of heat setting rollers.

(59) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(60) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1170 dtex, breaking strength 8.3 cN/dtex, deviation rate of linear density −0.2%, breaking strength CV value 2.3%, elongation at break 12.5%, deviation rate of elongation 1.0%, elongation at break CV value 7.0%, elongation at 4.0 cN/dtex load 6.6%, deviation rate of elongation at 4.0 cN/dtex load 0.3%, interlacing degree 8/m, dry heat shrinkage 2.6% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 52N or 58N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

Example 4

(61) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(62) (1) Preparation of modified polyester

(63) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(64) (a) mixing isobutanol and 41% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 6:1, then carrying out the reaction with a stirring at 110° C. for 4.8 hr to obtain potassium isobutanol;

(65) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.4:3.0 and cooling the system to 0° C.;

(66) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.3:2.6, then starting the reaction at 35° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(67) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 3:10:0.01 and then carrying out the reaction accompanied with a continuous hydrogen input at 40° C. for 60 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(68) (1.3) Esterification

(69) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.5:0.03 into a slurry, then adding in antimony glycol, titanium dioxide and trimethyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.20 mPa at 255° C., finally ending the reaction when the water distillation reaching 93% of the theoretical value, wherein the additions of antimony glycol, titanium dioxide and trimethyl phosphate being 0.045 wt %, 0.24 wt % and 0.025 wt % relative to the amount of terephthalic acid, respectively;

(70) (1.3) Polycondensation

(71) for the esterification products, smoothly reducing the pressure to 495 Pa (absolute value) within 38 min and carrying out reaction at 255° C. for 38 min, successively, further reducing the pressure to 97 Pa (absolute value) and continuing the reaction at 276° C. for 67 min, and finally obtaining a modified polyester with a molecular weight of 32000 Da and a molecular weight distribution index of 1.92;

(72) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.1 dL/g through the solid state polycondensation;

(73) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(74) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 4.8%, through the space formed by a pair of parallel hot plates (240° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.4 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 8 mm from both sides, therein the hot plates are 346 mm from the winding roller and 250 mm from the last set of heat setting rollers.

(75) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(76) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1370 dtex, breaking strength 7.9 cN/dtex, deviation rate of linear density 1.0%, breaking strength CV value 2.4%, elongation at break 12.0%, deviation rate of elongation 1.0%, elongation at break CV value 6.9%, elongation at 4.0 cN/dtex load 6.5%, deviation rate of elongation at 4.0 cN/dtex load −0.3%, interlacing degree 7/m, dry heat shrinkage 2.7% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 52N or 59N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

Example 5

(77) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(78) (1) Preparation of modified polyester

(79) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(80) (a) mixing isobutanol and 50% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5.4:1, then carrying out the reaction with a stirring at 110° C. for 5 hr to obtain potassium isobutanol;

(81) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.4:2.6 and cooling the system to 4° C.;

(82) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.2:3.0, then starting the reaction at 28° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(83) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 2.5:10:0.03 and then carrying out the reaction accompanied with a continuous hydrogen input at 44° C. for 53 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(84) (1.3) Esterification

(85) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.6:0.04 into a slurry, then adding in antimony acetate, titanium dioxide and trimethyl phosphate and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.25 MPa at 256° C., finally ending the reaction when the water distillation reaching 94% of the theoretical value, wherein the additions of antimony acetate, titanium dioxide and trimethyl phosphate being 0.05 wt %, 0.20 wt % and 0.03 wt % relative to the amount of terephthalic acid, respectively;

(86) (1.3) Polycondensation

(87) for the esterification products, smoothly reducing the pressure to 492 Pa (absolute value) within 40 min and carrying out reaction at 256° C. for 40 min, successively, further reducing the pressure to 95 Pa (absolute value) and continuing the reaction at 278° C. for 72 min, and finally obtaining a modified polyester with a molecular weight of 33030 Da and a molecular weight distribution index of 1.95;

(88) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.15 dL/g through the solid state polycondensation;

(89) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(90) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 4.0%, through the space formed by a pair of parallel hot plates (220° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.6 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 8.5 mm from both sides, therein the hot plates are 368 mm from the winding roller and 260 mm from the last set of heat setting rollers.

(91) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(92) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1290 dtex, breaking strength 8.3 cN/dtex, deviation rate of linear density 1.0%, breaking strength CV value 2.3%, elongation at break 12.9%, deviation rate of elongation 1.0%, elongation at break CV value 6.6%, elongation at 4.0 cN/dtex load 6.2%, deviation rate of elongation at 4.0 cN/dtex load 0.1%, interlacing degree 8/m, dry heat shrinkage 2.6% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 42N or 60N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

Example 6

(93) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(94) (1) Preparation of modified polyester

(95) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(96) (a) mixing isobutanol and 40% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5:1, then carrying out the reaction with a stirring at 106° C. for 4.5 hr to obtain potassium isobutanol;

(97) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.3:2.0 and cooling the system to 2° C.;

(98) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.3:2.5, then starting the reaction at 32° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(99) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 2:10:0.01 and then carrying out the reaction accompanied with a continuous hydrogen input at 48° C. for 50 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(100) (1.2) Esterification

(101) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:1.8:0.05 into a slurry, then adding in antimony acetate, titanium dioxide and trimethyl phosphite and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.28 MPa at 258° C., finally ending the reaction when the water distillation reaching 94% of the theoretical value, wherein the additions of antimony acetate, titanium dioxide and trimethyl phosphite being 0.05 wt %, 0.20 wt % and 0.04 wt % relative to the amount of terephthalic acid, respectively;

(102) (1.3) Polycondensation

(103) for the esterification products, smoothly reducing the pressure to 490 Pa (absolute value) within 42 min and carrying out reaction at 258° C. for 42 min, successively, further reducing the pressure to 94 Pa (absolute value) and continuing the reaction at 280° C. for 82 min, and finally obtaining a modified polyester with a molecular weight of 34400 Da and a molecular weight distribution index of 1.96;

(104) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.18 dL/g through the solid state polycondensation;

(105) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(106) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 3.0%, through the space formed by a pair of parallel hot plates (215° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 3.8 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 9 mm from both sides, therein the hot plates are 384 mm from the winding roller and 280 mm from the last set of heat setting rollers.

(107) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(108) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1570 dtex, breaking strength 7.9 cN/dtex, deviation rate of linear density 1.0%, breaking strength CV value 2.4%, elongation at break 13.0%, deviation rate of elongation 1.2%, elongation at break CV value 6.6%, elongation at 4.0 cN/dtex load 7.0%, deviation rate of elongation at 4.0 cN/dtex load 0.8%, interlacing degree 6/m, dry heat shrinkage 2.7% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 51N or 61N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

Example 7

(109) A method for preparing the high-modulus-low-shrinkage activated PET industrial yarn, comprising the steps:

(110) (1) Preparation of modified polyester

(111) (1.1) Synthesizing 2,6,6-trimethyl-2,5-heptanediol

(112) (a) mixing isobutanol and 46% of KOH aqueous solution in the molar ratio of isobutanol to KOH as 5.5:1, then carrying out the reaction with a stirring at 100° C. for 4 hr to obtain potassium isobutanol;

(113) (b) removing the impurities from the system in step (a), then adding in xylene in the molar ratio of isobutanol to xylene as 1.3:2.6 and cooling the system to 5° C.;

(114) (c) adding 3-methyl-3-hydroxybutyne and 2,2-dimethylpropionaldehyde into the system of step (b) in a molar ratio of 3-methyl-3-hydroxybutyne:2,2-dimethylpropionaldehyde:xylene as 1:1.24:3.0, then starting the reaction at 25° C. for 3 hr, and obtaining octyne diol after a series of processes of cooling crystallization, centrifugation and drying;

(115) (d) mixing octyne diol, ethanol and Pd catalyst in a weight ratio of 3:10:0.03 and then carrying out the reaction accompanied with a continuous hydrogen input at 40° C. for 56 min, finally obtaining 2,6,6-trimethyl-2,5-heptanediol (just as demonstrated in Formula (I) with R═—H) through a series of processes of separation and purification;

(116) (1.2) Esterification

(117) concocting terephthalic acid, ethylene glycol and 2,6,6-trimethyl-2,5-heptanediol with an molar ratio of 1:2.0:0.03 into a slurry, then adding in antimony acetate, titanium dioxide and trimethyl phosphite and carrying out the esterification in a nitrogen atmosphere with a pressure of 0.3 MPa at 260° C., finally ending the reaction when the water distillation reaching 96% of the theoretical value, wherein the additions of antimony acetate, titanium dioxide and trimethyl phosphite being 0.05 wt %, 0.20 wt % and 0.05 wt % relative to the amount of terephthalic acid, respectively;

(118) (1.3) Polycondensation

(119) for the esterification products, smoothly reducing the pressure to 490 Pa (absolute value) within 50 min and carrying out reaction at 260° C. for 50 min, successively, further reducing the pressure to 92 Pa (absolute value) and continuing the reaction at 282° C. for 90 min, and finally obtaining a modified polyester with a molecular weight of 35000 Da and a molecular weight distribution index of 2.2;

(120) (1.4) increasing the intrinsic viscosity of the modified polyester to 1.2 dL/g through the solid state polycondensation;

(121) (2) converting the modified polyester into the high-modulus-low-shrinkage activated PET industrial yarn through a melt spinning technique including a series of steps such as melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling of activation oil agent, winding and pre-activation treating.

(122) The relaxation heat-treating indicates passing the PET yarns, with a wind overfeeding rate of 5.0%, through the space formed by a pair of parallel hot plates (220° C.), therein the hot plates is installed between the last set of heat setting rollers and the winding roller, therein the hot plates are aligned in both side and have a length of 4 m along the passing direction of fiber; therein the fiber passes through the center of two hot plates and keep a distance of 10 mm from both sides, therein the hot plates are 400 mm from the winding roller and 300 mm from the last set of heat setting rollers.

(123) The technological parameters of the melt spinning are listed in Table 1 and those of the stretching and the heat setting are list in Table 2.

(124) The final obtained high-modulus-low-shrinkage activated PET industrial yarn possess the performance indices of fineness 1670 dtex, breaking strength 8.5 cN/dtex, deviation rate of linear density 1.2%, breaking strength CV value 2.0%, elongation at break 13.5%, deviation rate of elongation 1.5%, elongation at break CV value 6.4%, elongation at 4.0 cN/dtex load 7.0%, deviation rate of elongation at 4.0 cN/dtex load 0.8%, interlacing degree 9/m, dry heat shrinkage 3.0% (tested under the condition of 177° C.×10 min×0.05 cN/dtex), static adhesion to the vulcanized rubber 53N or 62N (determined through H-pull method when made into cord with a specification of 1100 dtex/192 F or 1670 dtex/192 F, respectively).

(125) TABLE-US-00001 TABLE 1 Example Example Example Example Example Example Example 1 2 3 4 5 6 7 Extruder 295° C. 301° C. 308° C. 310° C. 311° C. 312° C. 315° C. temperature Pack temperature 295° C. 296° C. 297° C. 298° C. 298° C. 299° C. 300° C. Die pressure 170 bar 172 bar 174 bar 175 bar 176 bar 178 bar 180 bar Cooling air 21° C. 22° C. 23° C. 24° C. 25° C. 25° C. 24° C. temperature Cooling air 70% 73% 80% 80% 80% 80% 80% moisture Cooling air speed 0.45 m/s 0.48 m/s 0.50 m/s 0.55 m/s 0.60 m/s 0.62 m/s 0.65 m/s Pre-interlacing 0.14 MPa 0.15 MPa 0.15 MPa 0.16 MPa 0.16 MPa 0.16 MPa 0.18 MPa pressure Interlacing pressure 0.20 mP 0.20 mPa 0.21 MPa 0.21 MPa 0.22 MPa 0.23 MPa 0.24 MPa Winding speed 2630 m/min 2800 m/min 2950 m/min 3300 m/min 3070 m/min 3200 m/min 3230 m/min Pre-activation 70° C. 72° C. 75° C. 72° C. 71° C. 70° C. 75° C. temperature Pre-activation time 15 h 16 h 20 h 16 h 15 h 18 h 18 h

(126) TABLE-US-00002 TABLE 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Roller 1 speed 500 m/min 525 m/min 550 m/min 540 m/min 560 m/min 575 m/min 600 m/min Roller 2 speed 520 m/min 580 m/min 670 m/min 750 m/min 880 m/min 900 m/min 1000 m/min Roller 2 temperature 80° C. 83° C. 86° C. 90° C. 92° C. 96° C. 100° C. Roller 3 speed 1800 m/min 1900 m/min 2000 m/min 2200 m/min 2300 m/min 2400 m/min 2500 m/min Roller 3 temperature 100° C. 105° C. 110° C. 120° C. 125° C. 130° C. 150° C. Roller 4 speed 2800 m/min 2900 m/min 3000 m/min 3150 m/min 3230 m/min 3450 m/min 3500 m/min Roller 4 temperature 200° C. 210° C. 210° C. 220° C.; 230° C. 240° C. 250° C. Roller 5 speed 2800 m/min 2900 m/min 3000 m/min 3150 m/min 3230 m/min 3450 m/min 3500 m/min