Ultra-low shrinkage polyester industrial yarn and its preparation method

Abstract

The present invention discloses an ultra-low shrinkage polyester industrial yarn and its preparation method. The ultra-low shrinkage polyester industrial yarn is prepared by subjecting a polyester to dissolution, washing and solid state polycondensation followed by spinning. The ultra-low shrinkage polyester industrial yarn has a dry heat shrinkage rate of 1.80.25% under test conditions of 177 C.10 min0.05 cN/dtex. The polycondensation catalyst consists of magnesium ethylene glycol and antimony ethylene glycol, has a small thermal degradation coefficient. The present invention reduces oligomers during polymerization, reduces thermal degradation during processing, and as a result the invention greatly reduces impurities and nucleating agent in the polyester, leading to an increase in the probability of homogeneous nucleation based on the reduction of heterogeneous nucleation. The dissolution and washing of polyester further decreases oligomer content, facilitating the growth of the grain size and the optimization of crystal perfection in the ultra-low shrinkage polyester industrial yarn.

Claims

1. An ultra-low shrinkage industrial yarn having a dry heat shrinkage rate of 1.80.25%, under the testing condition of 177 C.10 min0.05 cN/dtex wherein the ultra-low shrinkage industrial yarn is obtained by the following process: subjecting the polyester to dissolution, washing and solid state tackifying followed by spinning, esterification of terephthalic acid and ethylene glycol and the polycondensation catalysed by a mixture of magnesium ethylene glycol and antimony ethylene glycol followed by granulation, wherein the carboxyl end group is less than 15 mol/t, the mass percentage of oligomer is lower than 0.5%, and weight percentage of diethylene glycol is lower than 0.5%; wherein the molecular formula of magnesium ethylene glycol is Mg(OCH.sub.2CH.sub.2OH.sub.2).sub.2; wherein the dissolution and washing refers to that the granulated slices are scoured and washed with water and a rinsing agent at 120-130 C. and 0.2-0.3 MPa.

2. The ultra-low shrinkage industrial yarn according to claim 1, wherein the density deviation is 1.5%, a breaking strength is 7.0 cN/dtex, the CV value of the breaking strength 2.5%, a breaking extension 20.01.5%, and the CV value of the breaking extension 7.0%.

3. The ultra-low shrinkage industrial yarn according to claim 1, wherein the mass ratio of magnesium ethylene glycol to antimony ethylene glycol in the mixture is 2-3:1.

4. A process for preparing an ultra-low shrinkage industrial yarn of claim 1, the process comprising: obtaining polyester by the esterification of tereplithalic acid and ethylene glycol and the polycondensation catalyzed by a mixture of magnesium ethylene glycol and antimony ethylene glycol, obtaining a polyester section by granulating; then the polyester section is ready for dissolution, washing and solid state polycondensation; finally, after measuring, extrusion, cooling, oiling, stretching, heat setting and winding, the ultra-low shrinkage polyester industrial yarn is prepared.

5. The process for preparing the ultra-low shrinkage industrial yarn according to claim 4, wherein the preparation method of the ultra-low shrinkage polyester industrial yarn includes: preparation of catalyst (magnesium ethylene glycol) adding ethylene glycol in the single-compartment electrolytic cell, magnesium chloride is the supporting electrolyte, the anode is comprised of magnesium, the cathode is graphite; at 50 to 60 C., the apparatus is operated about 10 to 12 h under DC, for the initial voltage 6 to 10V, cathodic current density 150 to 200 mA; after the electrolysis, the white suspension liquid is obtained followed by removing the electrodes, decompression filtration and washing by anhydrous alcohol, then obtaining the magnesium ethylene glycol after drying preparation of polyester, including the esterification and polycondensation using, by the esterification reaction, terephthalic acid and ethylene glycol as raw materials, adding polyether-inhibitor in to obtain esterification products after reaction; the esterification reaction needs the increase of pressure in the nitrogen atmosphere, and the pressure is controlled in the scale of atmospheric pressure to 0.3 MPa, the temperature is controlled between 250 to 260 C.; the end of the reaction is set after the amount of distillate water in the esterification reaction reaches 90% of the theoretical value at least; the condensation reaction, includes the low vacuum stage and the high vacuum stage of the condensation reaction: in the low vacuum stage of such condensation reaction, the catalyst and stabilizer need to be added into the esterification production; the condensation reaction will start under the condition of negative pressure; In such period, the pressure needs to be pumped smoothly from atmospheric pressure to the pressure lower than the absolute pressure 500 Pa, and the temperature needs to be controlled between 260 to 270 C.; the reaction time should be 30 to 50 mins; the catalyst the reaction used is the mixture of magnesium ethylene glycol and antimony ethylene glycol; the high vacuum stage of the condensation reaction requires continuously pumping vacuum after the low vacuum period in order to ensure that the reaction pressure is decreased to absolute pressure lower than 100 Pa; the reaction temperature needs to be controlled between 275 and 280 C., and the reaction time needs to be 50-90 mins; then the polyester is prepared and the polyester section can be made through granulation; dissolution and washing the polyester section is scoured and washed with water and rinsing agent at 120 to 130 C. and 0.2 to 0.3 MPa for 3 to 5 h followed by washing with water; solid state polycondensation the intrinsic viscosity of the polyester section is raised to 1.0 to 1.2 dL/g through the solid state polycondensation, which can be regarded as high-viscosity chips; main process parameters of spinning the temperature of extrusion is 290 to 320 C.; the air temperature of cooling is 20 to 30 C.; the process of stretching and heat setting, GR-1 at speed of 450 to 600 m/min, temp: room temperature; GR-2 at speed of 480 to 1000 m/min, temp: 80 to 100 C.; GR-3 at speed of 1800 to 2500 m/min, temp: 100 to 150 C.; GR-4 at speed of 2800 to 3500 m/min, temp: 200 to 250 C.; GR-5 at speed of 2800 to 3500 m/min, temp: 200 to 250 C.; GR-6 at speed of 2600 to 3400 m/min, temp: 150 to 220 C.; the winding speed is 2600 to 3400 m/min.

6. The process for preparing the ultra-low shrinkage industrial yarn according to claim 4, wherein the molar ratio of the ethylene glycol to terephthalic acid is 1.2:1 to 2.0:1.

7. The process for preparing the ultra-low shrinkage industrial yarn according to claim 5, wherein the mass ratio of magnesium ethylene glycol to antimony ethylene glycol in their mixture is 2 to 3:1; the mass of the catalyst is 0.01-0.05% of the terephthalic acid; the stabilizer is chosen from triphenyl phosphate, trimethyl phosphate and trimethyl phosphite; the mass of stabilizer is 0.01-0.05% of the terephthalic acid.

8. The process for preparing the ultra-low shrinkage industrial yarn according to claim 5, wherein the mass ratio of water to the rinsing agent is 100:4 to 100:3, and the ratio of polyester section to water and rinsing agent is 1:5-10, the rinsing agent is selected from one of 2-ethoxyethanol, 2-propoxyethanol and ethylene glycol monobutyl ether.

9. The process for preparing the ultra-low shrinkage industrial yarn according to claim 5, wherein the cleaning means washing the polyester sections with 70-80 C. water for 10-15 min after scouring the polyester sections, then washing them with cold water, and dry and cool down to make the sections prepared.

10. The process for preparing the ultra-low shrinkage industrial yarn according to claim 5, wherein the polyether inhibitor is chosen from the sodium acetate and calcium acetate, the mass of plyether-inhibitor is 0.01-0.05% of tereplithalic acid.

11. The process for preparing the ultra-low shrinkage industrial yarn according to claim 5, wherein the molar ratio of the ethylene glycol to terephthalic acid is 1.2:1 to 2.0:1.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Hereinafter, the present invention will be described in more detail by the following examples. It should be noticed that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. In addition, it should be noticed that after reading the content of the present invention, those skilled in this field can make various modifications or changes to the present invention, and these equivalent forms also apply to the scope of the appended claims of this application.

(2) The preparation method of the ultra-low shrinkage polyester industrial yarn of the invention comprises the following steps: polycondensing terephthalic acid and ethylene glycol through esterification and obtaining polyester under the catalysis of a mixture of magnesium glycol and antimony ethylene glycol. Polyester sections are obtained by granulation, and then ultra-low shrinkage polyester industrial yarn is prepared through solvent cleaning and solid state polycondensation, then metered, extruded, cooled, oiled, stretched, heat-set and wound.

Example 1

(3) A process for preparing an ultra-low shrinkage polyester industrial yarn, wherein the main process is:

(4) 1. Preparation of Catalyst Magnesium Glycol:

(5) Add ethylene glycol into the single-compartment electrolytic cell, magnesium chloride is electrolyte, the anode is magnesium, the cathode is graphite. Under DC, the initial voltage is 6V, the cathode current density is 150 mA, and electrolysis is carried out for 10 hours at 50 C. Remove the electrode after the electrolysis, we can get white suspension. Filter it under reduced pressure, wash the white solid with anhydrous ethanol, and we get magnesium ethylene glycol.

(6) 2. Preparation of Polyester, Including Esterification and Polycondensation:

(7) Esterification Reaction:

(8) Using terephthalic acid and ethylene glycol as raw materials, ethylene glycol and terephthalic acid molar ratio of 1.2:1, adding plyether-inhibitor sodium acetate, sodium acetate dosage of terephthalic acid in an amount of 0.01% by weight. Start esterification reaction under nitrogen atmosphere pressure, and control the pressure at atmospheric pressure, the temperature at 250 C. When esterified water distillate amount reaches 91% of the theoretical value of the esterification, reaction ends.

(9) Polycondensation Reaction:

(10) Including polycondensation reaction of low vacuum phase and polycondensation reaction high vacuum phase:

(11) In the polycondensation reaction low-vacuum stage, add catalyst and the stabilizer acid triphenyl ester into the esterification product. The acid triphenyl ester dosage is 0.01% of terephthalic acid by weight, and the amount of catalyst is 0.01% of terephthalic acid by mass. The polycondensation reaction is started under the condition of negative pressure, the pressure is steadily pumped from the atmospheric pressure to the absolute pressure of 498 Pa, the temperature is controlled at 260 C., and the reaction time is 30 minutes. The catalyst is a mixture of magnesium ethylene glycol and antimony ethylene glycol, in which magnesium glycol and antimony ethylene glycol mass ratio is 2:1;

(12) After the polycondensation reaction the low-vacuum stage, the vacuum is continued to reduce the reaction pressure to 98 Pa, the reaction temperature is controlled at 275 C., and the reaction time is 50 minutes. The polyester sections are obtained by granulation.

(13) 3. Solvent Cleaning

(14) Polyester sections are washed with water and rinsing agent ethylene glycol monoethyl ether at 120 C. and 0.2 MPa for 3 hours. After washing, the polyester sections are washed with hot water at 70 C. for 10 minutes and then washed with cold water. After drying and cooling, the mass ratio of water to the rinsing agent is 100:3, the ratio of the polyester slice to the water and the rinsing agent, that is, the solid to liquid ratio is 1:5;

(15) 4. Solid-Phase Polycondensation:

(16) The obtained polyester sections are solidified by polycondensation to increase the intrinsic viscosity of the polyester sections to 1.0 dL/g, that is, high-viscosity sections.

(17) 5. The Main Process Parameters in Spinning:

(18) The temperature of extrusion is 290 C.,

(19) The air temperature of cooling is 20 C.,

(20) The process of stretching and heat setting:

(21) GR-1 speed 450 m/min, temp: room temperature,

(22) GR-2 speed 480 m/min, temp: 80 C.,

(23) GR-3 speed 1800 m/min, temp: 100 C.,

(24) GR-4 speed 2800 m/min, temp: 200 C.,

(25) GR-5 speed 2800 m/min, temp: 200 C.,

(26) GR-6 speed 2600 m/min, temp: 200 C.,

(27) The winding speed is 2600 m/min.

(28) The ultra-low shrinkage polyester industrial yarn obtained wider the conditions of a temperature of 177 C.10 min0.05 cN/dtex has the thy heat shrinkage rate of 2.05%. Additionally, the linear density deviation rate is 1.4%, breaking strength is 7.1 cN/dtex, CV value of breaking strength is 2.3%, breaking extension is 21.5% and CV value of breaking extension is 6.8%.

Example 2

(29) An ultra-low shrinkage polyester industrial yarn preparation method, the main process is:

(30) 1. Preparation of Catalyst Magnesium Glycol:

(31) Add ethylene glycol into the single-compartment electrolytic cell, magnesium chloride is electrolyte, the anode is magnesium, the cathode is graphite. Under DC, the initial voltage is 10V the cathode current density is 200 mA, and electrolysis is carried out for 12 hours at 60 C. Remove the electrode after the electrolysis, we can get white suspension. Filter it under reduced pressure, wash the white solid with anhydrous ethanol, and we get magnesium ethylene glycol.

(32) 2. Preparation of Polyester, Including Esterification and Polycondensation:

(33) Esterification Reaction:

(34) Using terephthalic acid and ethylene glycol as raw materials, ethylene glycol and terephthalic acid molar ratio of 2.0:1, adding plyether-inhibitor calcium acetate, calcium acetate dosage of terephthalic acid in an amount of 0.05% by weight. Start esterification reaction under nitrogen atmosphere pressure, and control the pressure at 0.3 MPa, the temperature at 260 C. When esterified water distillate amount reaches 92% of the theoretical value of the esterification, reaction ends.

(35) Polycondensation Reaction:

(36) Including polycondensation reaction of low vacuum phase and polycondensation reaction high vacuum phase:

(37) In the polycondensation reaction low-vacuum stage, add catalyst and the stabilizer trimethyl phosphate into the esterification product. The trimethyl phosphate dosage is 0.02% of terephthalic acid by weight, and the amount of catalyst is 0.02% of terephthalic acid by mass. The polycondensation reaction is started under the condition of negative pressure, the pressure is steadily pumped from the atmospheric pressure to the absolute pressure of 495 Pa, the temperature is controlled at 265 C., and the reaction time is 40 minutes. The catalyst is a mixture of magnesium ethylene glycol and antimony ethylene glycol, in which magnesium glycol and antimony ethylene glycol mass ratio is 3:1;

(38) After the polycondensation reaction in the low-vacuum stage, the vacuum is continued to reduce the reaction pressure to 98 Pa, the reaction temperature is controlled at 278 C., and the reaction time is 80 minutes. The polyester sections are obtained by granulation.

(39) 3. Solvent Cleaning

(40) Polyester sections are washed with water and rinsing agent ethylene glycol monopropyl ether at 125 C. and 0.25 MPa for 4 hours. After washing, the polyester sections are washed with hot water at 78 C. for 12 minutes and then washed with cold water. After drying and cooling, the mass ratio of water to the rinsing agent is 100:4, the ratio of the polyester slice to the water and the rinsing agent, that is, the solid to liquid ratio is 1:9;

(41) 4. Solid-Phase Polycondensation:

(42) The obtained polyester sections are solidified by polycondensation to increase the intrinsic viscosity of the polyester sections to 1.1 dL/g, that is, high-viscosity sections.

(43) 5. The Main Process Parameters in Spinning:

(44) The temperature of extrusion is 300 C.,

(45) The air temperature of cooling is 25 C.,

(46) The process of stretching, heat setting:

(47) GR-1 speed 500 m/min, temperature is room temperature,

(48) GR-2 speed 580 m/min, temp: 90 C.,

(49) GR-3 speed 2000 m/min, temp: 120 C.,

(50) GR-4 speed 3000 m/min, temp: 220 C.,

(51) GR-5 speed 3000 m/min, temp: 220 C.,

(52) GR-6 speed 2700 m/min temp: 220 C.,

(53) The winding speed is 2700 m/min.

(54) The ultra-low shrinkage polyester industrial yarn obtained under the conditions of a temperature of 177 C.10 min0.05 cN/dtex has the dry heat shrinkage rate of 1.55%. Additionally, the linear density deviation rate of 1.5%, breaking strength of 8.2 cN/dtex, CV value of breaking strength is 2.2%, breaking extension is 18.5% and CV value of breaking extension is 6.2%.

Example 3

(55) An ultra-low shrinkage polyester industrial yarn preparation method, the main process is:

(56) 1. Preparation of Catalyst Magnesium Glycol:

(57) Add ethylene glycol into the single-compartment electrolytic cell, magnesium chloride is electrolyte, the anode is magnesium, the cathode is graphite. Under DC, the initial voltage is 8V, the cathode current density is 160 mA, and electrolysis is carried out for 11 hours at 56 C. Remove the electrode after the electrolysis, we can get white suspension. Filter it under reduced pressure, wash the white solid with anhydrous ethanol, and we get magnesium ethylene glycol.

(58) 2. Preparation of Polyester, Including Esterification and Polycondensation:

(59) Esterification Reaction:

(60) Using terephthalic acid and ethylene glycol as raw materials, ethylene glycol and terephthalic acid molar ratio of 1.8:1, adding plyether-inhibitor sodium acetate, sodium acetate dosage of terephthalic acid in an amount of 0.03% by weight. Start esterification reaction under nitrogen atmosphere pressure, and control the pressure at 0.2 MPa, the temperature at 255 C. When esterified water distillate amount reaches 95% of the theoretical value of the esterification, reaction ends.

(61) Polycondensation Reaction:

(62) Including polycondensation reaction of low vacuum phase and polycondensation reaction high vacuum phase:

(63) In the polycondensation reaction low-vacuum stage, add catalyst and the stabilizer trimethyl phosphite into the esterification product. The trimethyl phosphite dosage is 0.03% of terephthalic acid by weight, and the amount of catalyst is 0.04% of terephthalic acid by mass. The polycondensation reaction is started under the condition of negative pressure, the pressure is steadily pumped from the atmospheric pressure to the absolute pressure of 495 Pa, the temperature is controlled at 266 C., and the reaction time is 38 minutes. The catalyst is a mixture of magnesium ethylene glycol and antimony ethylene glycol, in which magnesium glycol and antimony ethylene glycol mass ratio is 3:1;

(64) After the polycondensation reaction in the low-vacuum stage, the vacuum is continued to reduce the reaction pressure to 99 Pa, the reaction temperature is controlled at 277 C., and the reaction time is 70 minutes. The polyester sections are obtained by granulation.

(65) 3. Solvent Cleaning

(66) Polyester sections are washed with water and rinsing agent ethylene glycol monobutyl ether at 128 C. and 0.25 MPa for 3 hours. After washing, the polyester sections are washed with hot water at 75 C. for 12 minutes and then washed with cold water. After drying and cooling, the mass ratio of water to the rinsing agent is 100:4, the ratio of the polyester slice to the water and the rinsing agent, that is, the solid to liquid ratio is 1:8;

(67) 4. Solid-Phase Polycondensation:

(68) The obtained polyester sections are solidified by polycondensation to increase the intrinsic viscosity of the polyester sections to 1.2 dL/g, that is, high-viscosity sections.

(69) 5. The Main Process Parameters in Spinning:

(70) The temperature of extrusion is 290 C.,

(71) The air temperature of cooling is 20 C.,

(72) The process of stretching, heat setting:

(73) GR-1 speed 450 m/min, temp: room temperature,

(74) GR-2 speed 480 m/min, temp: 80 C.,

(75) GR-3 speed 1800 m/min, temp: 100 C.,

(76) GR-4 speed 2800 m/min, temp: 200 C.,

(77) GR-5 speed 2800 m/min, temp: 200 C.,

(78) GR-6 speed 2600 m/min, temp: 200 C.,

(79) The winding speed is 2600 m/min.

(80) The ultra-low shrinkage polyester industrial yarn obtained under the conditions of a temperature of 177 C.10 min0.05 cN/dtex has the dry heat shrinkage rate of 1.8%. Additionally, the linear density deviation rate is 1.2%, breaking strength is 8.5 cN/dtex, CV value of breaking strength is 1.8%, breaking extension is 20.1% and CV value of breaking extension is 6.8%.

Example 4

(81) An ultra-low shrinkage polyester industrial yarn preparation method, the main process is:

(82) 1. Preparation of Catalyst Magnesium Glycol:

(83) Add ethylene glycol into the single-compartment electrolytic cell, magnesium chloride is electrolyte, the anode is magnesium, the cathode is graphite. Under DC, the initial voltage is 10V, the cathode current density is 150 mA, and electrolysis is carried out for 12 hours at 50 C. Remove the electrode after the electrolysis, we can get white suspension. Filter it under reduced pressure, wash the white solid with anhydrous ethanol, and we get magnesium ethylene glycol.

(84) 2. Preparation of Polyester, Including Esterification and Polycondensation:

(85) Esterification Reaction:

(86) Using terephthalic acid and ethylene glycol as raw materials, ethylene glycol and terephthalic acid molar ratio of 1.2:1, adding plyether-inhibitor sodium acetate, sodium acetate dosage of terephthalic acid in an amount of 0.04% by weight. Start esterification reaction under nitrogen atmosphere pressure, and control the pressure at 0.2 MPa, the temperature at 258 C. When esterified water distillate amount reaches 96% of the theoretical value of the esterification, reaction ends.

(87) Polycondensation Reaction:

(88) Including polycondensation reaction of low vacuum phase and polycondensation reaction high vacuum phase:

(89) In the polycondensation reaction low-vacuum stage, add catalyst and the stabilizer acid triphenyl ester into the esterification product. The acid triphenyl ester dosage is 0.03% of terephthalic acid by weight, and the amount of catalyst is 0.04% of terephthalic acid by mass. The polycondensation reaction is started under the condition of negative pressure, the pressure is steadily pumped from the atmospheric pressure to the absolute pressure of 495 Pa, the temperature is controlled at 265 C., and the reaction time is 30 minutes. The catalyst is a mixture of magnesium ethylene glycol and antimony ethylene glycol, in which magnesium glycol and antimony ethylene glycol mass ratio is 3:1;

(90) After the polycondensation reaction in the low-vacuum stage, the vacuum is continued to reduce the reaction pressure to 98 Pa, the reaction temperature is controlled at 277 C., and the reaction time is 70 minutes. The polyester sections are obtained by granulation.

(91) 3. Solvent Cleaning

(92) Polyester sections are washed with water and rinsing agent ethylene glycol monoethyl ether at 120 C. and 0.3 MPa for 5 hours. After washing, the polyester sections are washed with hot water at 72 C. for 12 minutes and then washed with cold water. After drying and cooling, the mass ratio of water to the rinsing agent is 100:4, the ratio of the polyester slice to the water and the rinsing agent, that is, the solid to liquid ratio is 1:8;

(93) 4. Solid-Phase Polycondensation:

(94) The obtained polyester sections are solidified by polycondensation to increase the intrinsic viscosity of the polyester sections to 1.2 dL/g, that is, high-viscosity sections.

(95) 5. The Main Process Parameters in Spinning:

(96) The temperature of extrusion of 320 C.,

(97) The air temperature of cooling is 30 C.,

(98) The process of stretching, heat setting:

(99) GR-1 speed 600 m/min, temp: room temperature,

(100) GR-2 speed 1000 m/min. temp: 100 C.,

(101) GR-3 speed 2500 m/min, temp: 150 C.,

(102) GR-4 speed 3500 m/min, temp: 210 C.,

(103) GR-5 speed 3500 m/min, temp: 210 C.,

(104) GR-6 speed 3400 m/min, temp: 210 C.,

(105) The winding speed is 3400 m/min.

(106) The ultra-low shrinkage polyester industrial yarn obtained under the conditions of a temperature of 177 C.10 min0.05 cN/dtex has the div heat shrinkage rate of 1.82%. Additionally, the linear density deviation rate is 0.9%, breaking strength is 8.6 cN/dtex, CV value of breaking strength is 2.1%, breaking extension is 19.5% and CV value of breaking extension is 6.4%.