阅读说明：本技术 一种降低聚酯工业丝纺丝温度的方法 (Method for reducing spinning temperature of polyester industrial yarn ) 是由 张玉梅 陈康 王彤 汤方明 张晶晶 王山水 陈瑞 于 2021-06-25 设计创作，主要内容包括：本发明涉及一种降低聚酯工业丝纺丝温度的方法,向聚酯熔体中引入改性聚四氟乙烯后,按聚酯工业丝的加工工艺进行纺丝；聚酯为聚对苯二甲酸乙二醇酯,聚酯熔体的特性粘度为0.85～0.95dL/g；聚酯熔体中无小分子流动促进剂；改性聚四氟乙烯为平均粒径不超过600nm的表面含有酯基的聚四氟乙烯纳米粒子,酯基的含量为10～100ppm；熔融温度280～290℃,输送温度275～285℃,挤出温度270～280℃；输送开始前至挤出结束后,聚酯熔体的特性粘度降不大于0.02dL/g；最终制得的聚酯工业丝中改性聚四氟乙烯的含量不超过0.5wt％。本方法利用聚四氟乙烯摩擦系数极低的特点,减小聚酯熔体的流动阻力,降低输送和挤出温度,保证挤出后聚酯的粘度降不大于0.02dL/g,大大降低了聚酯制备和纺丝过程中的能耗。(The invention relates to a method for reducing the spinning temperature of polyester industrial yarn, which comprises the steps of introducing modified polytetrafluoroethylene into a polyester melt, and spinning according to the processing technology of the polyester industrial yarn; the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.85-0.95 dL/g; the polyester melt is free of micromolecular flow promoters; the modified polytetrafluoroethylene is polytetrafluoroethylene nanoparticles with the average particle size not more than 600nm and ester groups on the surface, and the content of the ester groups is 10-100 ppm; the melting temperature is 280-290 ℃, the conveying temperature is 275-285 ℃, and the extrusion temperature is 270-280 ℃; before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced by not more than 0.02 dL/g; the content of the modified polytetrafluoroethylene in the finally prepared polyester industrial yarn is not more than 0.5 wt%. The method utilizes the characteristic of extremely low friction coefficient of the polytetrafluoroethylene to reduce the flow resistance of the polyester melt, reduce the conveying and extruding temperature, ensure that the viscosity of the extruded polyester is not more than 0.02dL/g, and greatly reduce the energy consumption in the polyester preparation and spinning processes.)

1. A method for reducing the spinning temperature of polyester industrial yarn is characterized in that modified polytetrafluoroethylene is introduced into a polyester melt, and then spinning is carried out according to the processing technology of the polyester industrial yarn;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.85-0.95 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the average particle size of the polytetrafluoroethylene nanoparticles with ester groups on the surfaces is not more than 600nm, and the content of the ester groups is 10-100 ppm;

the processing parameters of the polyester industrial yarn comprise: the melting temperature is 280-290 ℃, the conveying temperature is 275-285 ℃, and the extrusion temperature is 270-280 ℃;

before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced by not more than 0.02 dL/g;

the content of the modified polytetrafluoroethylene in the finally prepared polyester industrial yarn is not more than 0.5 wt%.

2. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the introduction process is as follows: and respectively metering the dried polyester chips and the dried modified polytetrafluoroethylene, mixing the polyester chips and the dried modified polytetrafluoroethylene according to the proportion required by the finally prepared polyester industrial yarn, and feeding the polyester industrial yarn into a screw for melting.

3. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the introduction process is as follows: respectively metering the dried polyester chips and the dried modified polytetrafluoroethylene to prepare modified polytetrafluoroethylene/polyester master batches, respectively metering the dried modified polytetrafluoroethylene/polyester master batches and the dried polyester chips, mixing the metered modified polytetrafluoroethylene/polyester master batches and the dried polyester master batches according to the proportion required by the finally prepared polyester industrial yarns, and feeding the mixture into a screw to be melted.

4. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the introduction process is as follows: and respectively metering the dried polyester chips and the dried modified polytetrafluoroethylene to prepare modified polytetrafluoroethylene/polyester master batches, melting the dried modified polytetrafluoroethylene/polyester master batches, and mixing the melted modified polytetrafluoroethylene/polyester master batches with the polyester melt according to the proportion required by the finally prepared polyester industrial yarn.

5. The method for reducing the spinning temperature of the polyester industrial yarn according to claim 3 or 4, wherein the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 10-20 wt%.

6. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the polytetrafluoroethylene nanoparticles having ester groups on the surface have an average particle diameter of 300-500 nm.

7. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → shaping → winding.

8. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 7, wherein the processing parameters of the polyester industrial yarn further comprise: the conveying pressure is 90-300 bar, the conveying speed is 0.5-1.5 m/min, the cooling temperature is 12-17 ℃, the temperature of a first roller is 65-75 ℃, the temperature of a second roller is 80-90 ℃, the temperature of a third roller is 115-130 ℃, the temperature of a fourth roller is 200-240 ℃, the temperature of a fifth roller is 150-170 ℃, the speed of the first roller is 440-550 m/min, the post-stretching stage number is 5, the post-stretching multiplying power is 5.5-6.5, the stretching ratio of a spray head is 30-300, the winding speed is 2420-3600 m/min, the pressure of a component is 16-25 MPa, and the service cycle of the component is 60-90 days.

9. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the content of the modified polytetrafluoroethylene in the finally prepared polyester industrial yarn is 0.01-0.05 wt%.

10. The method for reducing the spinning temperature of the polyester industrial yarn as claimed in claim 1, wherein the filament number of the finally prepared polyester industrial yarn is 3 to 10dtex, the breaking strength is 7.6 to 8.8cN/dtex, and the elongation at break is 10.0 to 20.0%.

Technical Field

The invention belongs to the technical field of polyester industrial yarns, and relates to a method for reducing the spinning temperature of polyester industrial yarns.

Background

The polyester industrial yarn has the advantages of mature processing technology, environmental protection, flexibility and strength, is praised as a high-performance fiber with the highest cost performance, and is widely applied to various fields such as engineering construction, transportation, aerospace, military protection and the like.

The preparation of industrial polyester yarn features that high molecular weight polyester is used as material and has great viscosity, so that the friction between molecules and wall of the yarn produces great degradation. In addition, the preparation of high molecular weight polyester requires high temperature, high vacuum and long time conditions, and the high temperature and high pressure conditions are also required for conveying high-viscosity melt, so that the fixed investment cost of equipment is increased, a large amount of energy is consumed, the energy is not favorably saved, the consumption is reduced, and the production cost is increased; and the high temperature and high pressure are easy to cause melt instability, even cause degradation (viscosity reduction increase) of polyester, and influence the stability of spinning.

The temperature is reduced by adopting a method for reducing the molecular weight (the intrinsic viscosity is 0.75-0.84 dL/g), and the requirement on the mechanical property of the high-strength polyester industrial yarn cannot be met; although the melt viscosity can be reduced by adding the small molecular flow promoter at the same temperature, the mechanical property of the industrial yarn is obviously reduced, only little energy can be saved in the conveying process, and the effect is limited.

Therefore, the research on a novel method for reducing the spinning temperature of the polyester industrial yarn is of great significance.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide a method for reducing the spinning temperature of polyester industrial yarns.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for reducing the spinning temperature of polyester industrial yarn, after introducing the modified polytetrafluoroethylene into polyester melt, carry on the spinning according to the processing technology of the polyester industrial yarn;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.85-0.95 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the average particle size of the polytetrafluoroethylene nanoparticles with ester groups on the surface is not more than 600nm, the average particle size is not more than 600nm, defects generated in the fibers can be avoided, the fiber strength unevenness is further avoided to be large, the ester group content is 10-100 ppm, the compatibility with a polyester system is poor after the polytetrafluoroethylene nanoparticles are added when the ester group content is less than 10ppm, the compatibility of the polytetrafluoroethylene nanoparticles and the polyester is improved when the ester group content is more than 100ppm, but the requirement on the polytetrafluoroethylene nanoparticle modification process is strict, and batch production cannot be realized;

the processing parameters of the polyester industrial yarn comprise: the melting temperature is 280-290 ℃ (290-310 ℃ in the prior art), the conveying temperature is 275-285 ℃ (290-300 ℃ in the prior art), and the extrusion temperature is 270-280 ℃ (280-300 ℃ in the prior art);

the method for reducing the spinning temperature of the polyester industrial yarn in the prior art generally comprises the following steps: (1) reducing the molecular weight of the polyester; (2) adding a small molecule flow promoter into the polyester melt; the intrinsic viscosity of the polyester melt is 0.85-0.95 dL/g, and the polyester melt does not contain a micromolecular flow promoter, which is obviously different from the method in the prior art, the modified polytetrafluoroethylene is introduced into the polyester melt to reduce the spinning temperature of the polyester industrial yarn, the final melting temperature is 280-290 ℃, the conveying temperature is 275-285 ℃, the extrusion temperature is 270-280 ℃, and the final melting temperature is obviously lower than that in the prior art;

the intrinsic viscosity of the polyester melt is reduced to be not more than 0.02dL/g (the intrinsic viscosity of the polyester melt is reduced to be the absolute value of the difference between the intrinsic viscosity of the polyester melt before the conveying starts and the intrinsic viscosity of the polyester melt after the extrusion finishes) before the conveying starts and after the extrusion finishes; the viscosity of the polyester is reduced in the whole process, so that the polyester industrial yarn has excellent mechanical property;

the content of the modified polytetrafluoroethylene in the finally prepared polyester industrial yarn is not more than 0.5 wt%, so that the modified polytetrafluoroethylene is ensured to be distributed in an amorphous region of the polyester, the crystallization of the polyester is not influenced, and the industrial yarn is ensured to have sufficient mechanical properties.

As a preferred technical scheme:

the method for reducing the spinning temperature of the polyester industrial yarn introduces the following processes: and (3) respectively metering the dried polyester chips (with the water content of 20-100 ppm) and the dried modified polytetrafluoroethylene (with the water content of 20-100 ppm), mixing the polyester chips and the dried modified polytetrafluoroethylene according to the proportion required by the finally prepared polyester industrial yarn, and feeding the polyester industrial yarn into a screw for melting.

The method for reducing the spinning temperature of the polyester industrial yarn can also be introduced as follows: and (2) respectively metering the dried polyester chips (with the water content of 20-100 ppm) and the dried modified polytetrafluoroethylene (with the water content of 20-100 ppm), preparing modified polytetrafluoroethylene/polyester master batches, respectively metering the dried modified polytetrafluoroethylene/polyester master batches (with the water content of 20-100 ppm) and the dried polyester chips (with the water content of 20-100 ppm), mixing according to the proportion required by the finally prepared polyester industrial yarn, and feeding the mixture into a screw for melting.

The method for reducing the spinning temperature of the polyester industrial yarn can also be introduced by the following steps: and (2) respectively metering the dried polyester chips (with the water content of 20-100 ppm) and the dried modified polytetrafluoroethylene (with the water content of 20-100 ppm), preparing modified polytetrafluoroethylene/polyester master batches, melting the dried modified polytetrafluoroethylene/polyester master batches (with the water content of 20-100 ppm), and mixing the melted polyester with the polyester melt according to the proportion required by the finally prepared polyester industrial yarn.

According to the method for reducing the spinning temperature of the polyester industrial yarn, the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 10-20 wt%.

The method for reducing the spinning temperature of the polyester industrial yarn has the advantage that the average particle diameter of the ester-group-containing polytetrafluoroethylene nanoparticles is 300-500 nm.

The method for reducing the spinning temperature of the polyester industrial yarn comprises the following processing technological processes: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding; the spinning adopts a conventional spinning assembly; the surfaces of the melt conveying pipeline and the spinning assembly are not coated.

The method for reducing the spinning temperature of the polyester industrial yarn further comprises the following processing parameters: the conveying pressure is 90 to 300bar (generally 90 to 300bar in the prior art), the conveying speed is 0.5 to 1.5m/min (generally 0.5 to 1.5m/min in the prior art), the cooling temperature is 12 to 17 ℃ (generally 18 to 24 ℃ in the prior art), the first roller temperature is 65 to 75 ℃ (generally 75 to 85 ℃ in the prior art), the two roller temperature is 80 to 90 ℃ (generally 90 to 100 ℃ in the prior art), the three roller temperature is 115 to 130 ℃ (generally 125 to 140 ℃ in the prior art), the four roller temperature is 200 to 240 ℃ (generally 200 to 240 ℃ in the prior art), the five roller temperature is 150 to 170 ℃ (generally 150 to 170 ℃ in the prior art), the first roller speed is 440 to 550m/min (generally 440 to 650m/min in the prior art), the post-stretching stage is 5 (generally 5 in the prior art), the post-stretching multiplying factor is 5.5 to 6.5 (generally 5 to 6.5 in the prior art), and the spray head stretching ratio is 30 to 300 (generally 30 to 300 in the prior art), the winding speed is 2420-3600 m/min (generally 2600-3600 m/min in the prior art), the pressure of the component is 16-25 MPa (generally 16-25 MPa in the prior art), and the service cycle of the component is 60-90 days (generally 40-45 days in the prior art); compared with the prior art that the viscosity of the high-viscosity polyester melt is usually utilized to achieve the purpose of high strength of the finally spun fiber, but the high-viscosity polyester melt is easy to generate serious thermal degradation due to frictional heat in the subsequent conveying and extrusion processes, the viscosity reduction of the melt is reduced by adding the modified polytetrafluoroethylene nanometer, so that the intrinsic viscosity (0.85-0.95 dL/g) of the polyester melt can be properly reduced in the invention, the extrusion temperature and the conveying temperature of the melt are both reduced due to the reduction of the viscosity of the adopted polyester melt, the subsequent cooling and the stretching temperature from one roller to three rollers are reduced in order to match the reduction of the melt temperature, the cooling temperature in the prior art is reduced from 18-24 ℃ to 12-17 ℃, the temperature of the one roller is reduced from 75-85 ℃ to 65-75 ℃, the temperature of the two rollers is reduced from 90-100 ℃ to 80-90 ℃, the temperature of the three rollers is reduced from 125-140 ℃ to 115-130 ℃, because the nano particles of the modified polytetrafluoroethylene are added as impurities, the crystallization rate of a polyester system is reduced, and in order to ensure the crystallinity of the final industrial yarn product and meet the requirement of the strength of the polyester industrial yarn, the four-roller temperature and the five-roller temperature are kept unchanged.

According to the method for reducing the spinning temperature of the polyester industrial yarn, the content of the modified polytetrafluoroethylene in the finally prepared polyester industrial yarn is 0.01-0.05 wt%.

According to the method for reducing the spinning temperature of the polyester industrial yarn, the filament number of the finally prepared polyester industrial yarn is 3-10 dtex, the breaking strength is 7.6-8.8 cN/dtex, and the elongation at break is 10.0-20.0% measured according to the standard test method of GB/T14344-2008 chemical fiber filament tensile property experimental method.

The principle of the invention is as follows:

theoretically, the mechanical property can be improved by increasing the molecular weight of the polyester melt, but the increase of the molecular weight also brings about the problem of melt flow and spinning difficulty, so the prior art simply increases the melting temperature to reduce the melt viscosity and reduce the resistance of melt flow and spinning difficulty. However, the increase in the melting temperature and the heat generated by the frictional heat generation of the highly viscous melt tend to cause the local temperature to be too high, which leads to degradation of the polyester, and the decrease in the molecular weight leads to a greater decrease in the intrinsic viscosity of the polyester melt before the start of the transportation and after the end of the extrusion. The modified polytetrafluoroethylene with the average particle size not more than 600nm is added into the high-viscosity polyester melt with the intrinsic viscosity of 0.85-0.95 dL/g, on the premise that the molecular weight of the polyester is not changed by the modified polytetrafluoroethylene, the friction between molecular chains of the polyester melt and the wall of the polyester melt is reduced, so that the resistance in the flow process of the polyester melt is reduced, the melting temperature, the conveying temperature and the extrusion temperature can be reduced, the spinning process of the polyester cannot be influenced, the reduction of the melting temperature, the conveying temperature and the extrusion temperature reduces the thermal degradation in the flow process, and the intrinsic viscosity of the polyester melt is reduced to be not more than 0.02dL/g before the conveying is started until the extrusion is finished.

Has the advantages that:

(1) according to the method for reducing the spinning temperature of the polyester industrial yarn, the nano modified polytetrafluoroethylene is added into the polyester with the intrinsic viscosity of 0.85-0.95 dL/g, the flow resistance of the polyester melt is reduced by utilizing the characteristic of extremely low friction coefficient of the polytetrafluoroethylene, the melt conveying and extruding temperature is reduced, the viscosity of the extruded polyester is ensured to be reduced to be not more than 0.02dL/g, and the energy consumption in the polyester preparation and spinning processes is greatly reduced;

(2) the method for reducing the spinning temperature of the polyester industrial yarn is simple and easy to implement, and does not need complex process method regulation and control.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

The intrinsic viscosity of the polyester melt in the following examples was measured by: adopting phenol/1, 1,2, 2-tetrachloroethane (mass ratio is 50:50) as a solvent, fully dissolving a fully dried and weighed experimental sample at 90-100 ℃ to prepare a 0.5g/dL solution, naturally cooling the solution to room temperature, measuring by using an Ubbelohde viscometer with the diameter of 0.8mm, keeping the constant temperature water bath temperature at (25 +/-0.05) DEG C, recording the flowing time of the pure solvent and the solution, and calculating the intrinsic viscosity by a one-point method, wherein the intrinsic viscosity is calculated according to the following formula:

in the formula: eta_spTo increase specific viscosity (. eta.)_sp＝t₁/t₀-1，t₁Time of solution flow, t₀Time to pure solvent run-off); [ eta ]]Is intrinsic viscosity, dL/g; c is the solution concentration, g/dL.

Example 1

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with methacrylate volume content of 37.5%, and mixing with polytetrafluoroethylene nano-powder (polymerization degree of 5 × 10)³Average particle size of 300nm) was placed in the solution (mass ratio of polytetrafluoroethylene nano-powder to the solution was 1:2), and plasma treatment was performed in an argon atmosphere for 100 seconds to cause chemical graft polymerization of methacrylate on the surface of the polytetrafluoroethylene nano-powder to form a layer of graft polymer on the surface, thereby obtaining polytetrafluoroethylene nanoparticles having an average particle size of 300nm and an ester group content of 20ppm and containing ester groups on the surface.

The structural formula of the polytetrafluoroethylene nano particles containing ester groups on the surface is shown as a formula (I), wherein,

example 2

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with ethyl methacrylate volume content of 37.5%, mixing with polytetrafluoroethylene nano powder (polymerization degree of 5 × 10)³Average particle diameter of 350nm) in the solution (mass ratio of polytetrafluoroethylene nano powder to the solution is 1:2), treating with plasma in argon atmosphere for 150s to make ethyl methacrylate chemically graft-polymerize on the surface of the polytetrafluoroethylene nano powder to form a layer of graft polymer on the surface, and obtaining the ester-based graft polymer with average particle diameter of 350nmPolytetrafluoroethylene nanoparticles having ester groups on the surface in an amount of 30 ppm.

The structural formula of the polytetrafluoroethylene nano particles containing ester groups on the surface is shown as a formula (I), wherein,

example 3

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with propyl methacrylate volume content of 37.5%, mixing with polytetrafluoroethylene nano powder (polymerization degree of 5 × 10)³And the average particle diameter is 400nm) is placed in the solution (the mass ratio of the polytetrafluoroethylene nano powder to the solution is 1:2), plasma treatment is carried out in an argon atmosphere for 200s, propyl methacrylate is subjected to chemical graft polymerization on the surface of the polytetrafluoroethylene nano powder, a layer of graft polymer is formed on the surface, and the polytetrafluoroethylene nano particles with the average particle diameter of 400nm and the ester group content of 40ppm and containing the ester groups on the surface are obtained.

The structural formula of the polytetrafluoroethylene nano particles containing ester groups on the surface is shown as a formula (I), wherein,

example 4

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with butyl methacrylate volume content of 37.5%, and mixing with polytetrafluoroethylene nano-powder (polymerization degree of 5 × 10)³Average grain diameter of 450nm) is put into the solution (the mass ratio of the polytetrafluoroethylene nano powder to the solution is 1:2), and is treated by plasma in argon atmosphere for 300s, so that butyl methacrylate is subjected to chemical graft polymerization on the surface of the polytetrafluoroethylene nano powder, a layer of graft polymer is formed on the surface, and the polytetrafluoroethylene nano particle with the average grain diameter of 450nm and the ester group content of 60ppm and the surface containing the ester group is obtainedAnd (4) adding the active ingredients.

The structural formula of the polytetrafluoroethylene nano particles containing ester groups on the surface is shown as a formula (I), wherein,

example 5

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with volume content of amyl methacrylate of 37.5%, and mixing with polytetrafluoroethylene nano-powder (polymerization degree of 5 × 10)³Average particle size of 450nm) was placed in the solution (mass ratio of polytetrafluoroethylene nano-powder to the solution was 1:2), and treated with plasma in an argon atmosphere for 500 seconds to cause chemical graft polymerization of amyl methacrylate on the surface of the polytetrafluoroethylene nano-powder to form a layer of graft polymer on the surface, thereby obtaining polytetrafluoroethylene nanoparticles having an average particle size of 450nm and an ester group content of 80ppm and containing ester groups on the surface.

The structural formula of the polytetrafluoroethylene nano particles containing ester groups on the surface is shown as a formula (I), wherein,

example 6

The preparation method of the polytetrafluoroethylene nano-particles with ester groups on the surfaces comprises the following specific steps:

preparing chlorobenzene solution with hexyl methacrylate volume content of 37.5%, and mixing with polytetrafluoroethylene nano powder (polymerization degree of 5 × 10)³Average particle size of 400nm) was placed in the solution (mass ratio of polytetrafluoroethylene nano-powder to the solution was 1:2), and treated with plasma in an argon atmosphere for 600 seconds to cause chemical graft polymerization of hexyl methacrylate on the surface of the polytetrafluoroethylene nano-powder to form a layer of graft polymer on the surface, thereby obtaining polytetrafluoroethylene nanoparticles having an average particle size of 400nm and an ester group content of 100ppm and containing ester groups on the surface.

Containing ester groups on the surfaceThe structural formula of the polytetrafluoroethylene nano particles is shown as a formula (I), wherein,

example 7

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.85 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 1;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively metering dried polyester chips (the water content is 50ppm after drying) and dried modified polytetrafluoroethylene (the water content is 30ppm after drying), mixing according to the proportion required by the finally prepared polyester industrial yarn, and feeding the polyester industrial yarn into a screw for melting;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 280 ℃, the conveying temperature is 275 ℃, the conveying pressure is 90bar, the conveying speed is 0.5m/min, the extrusion temperature is 270 ℃, the cooling temperature is 12 ℃, the one-roller temperature is 65 ℃, the two-roller temperature is 80 ℃, the three-roller temperature is 115 ℃, the four-roller temperature is 210 ℃, the five-roller temperature is 150 ℃, the one-roller speed is 440m/min, the rear stretching stage is 5, the rear stretching ratio is 5.5, the spray head stretching ratio is 30, the winding speed is 2420m/min, the assembly pressure is 16MPa, and the assembly service cycle is 90 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.02 dL/g; the filament number of the prepared polyester industrial yarn is 10dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.01 wt%; the breaking strength is 7.6cN/dtex and the elongation at break is 20 percent according to the standard test method of GB/T14344 experiment method for tensile property of 2008 chemical fiber filament.

Comparative example 1

A process for preparing industrial polyester yarn, which is substantially the same as that of example 7, except that modified polytetrafluoroethylene is not introduced into the polyester melt, the conveying temperature is 290 ℃ (test shows that the conveying pressure cannot be lowered any more, otherwise, the conveying pressure is too high), and the extrusion temperature is 280 ℃ (test shows that the conveying pressure cannot be lowered any more, otherwise, the melt extrusion process is difficult, and filament yarn cannot be extruded smoothly).

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.05 dL/g; the breaking strength of the prepared polyester industrial yarn is 7.3cN/dtex and the elongation at break is 22 percent according to the standard test method of GB/T14344-2008 chemical fiber filament tensile property experimental method.

Compared with example 7, comparative example 1 has a larger intrinsic viscosity drop than example 7 and a smaller breaking strength than example 7 because the high-viscosity polyester melt is thermally degraded to a large extent during transportation and extrusion due to a large amount of heat generated by a large frictional force under high temperature conditions, the intrinsic viscosity of the polyester melt after transportation is more greatly reduced, and the breaking strength is reduced at the same draw down ratio.

Example 8

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.87 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 2;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively metering dried polyester chips (the water content is 50ppm after drying) and dried modified polytetrafluoroethylene (the water content is 30ppm after drying), mixing according to the proportion required by the finally prepared polyester industrial yarn, and feeding the polyester industrial yarn into a screw for melting;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 282 ℃, the conveying temperature is 277 ℃, the conveying pressure is 120bar, the conveying speed is 0.7m/min, the extrusion temperature is 272 ℃, the cooling temperature is 13 ℃, the first roller temperature is 66 ℃, the two roller temperature is 82 ℃, the three roller temperature is 118 ℃, the four roller temperature is 213 ℃, the five roller temperature is 153 ℃, the first roller speed is 460m/min, the rear stretching stage is 5, the rear stretching ratio is 5.7, the nozzle stretching ratio is 60, the winding speed is 2622m/min, the assembly pressure is 17MPa, and the assembly service cycle is 85 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.02 dL/g; the filament number of the prepared polyester industrial yarn is 8dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.02 wt%; the breaking strength is 7.8cN/dtex and the elongation at break is 18 percent according to the standard test method of GB/T14344 experiment method for tensile property of 2008 chemical fiber filament.

Example 9

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.89 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 3;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively metering dried polyester chips (the water content is 50ppm after drying) and dried modified polytetrafluoroethylene (the water content is 30ppm after drying), preparing modified polytetrafluoroethylene/polyester master batches, respectively metering the dried modified polytetrafluoroethylene/polyester master batches and the dried polyester chips, mixing according to the proportion required by the finally prepared polyester industrial yarns, and feeding the polyester industrial yarns into a screw for melting; the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 10 wt%;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 284 ℃, the conveying temperature is 279 ℃, the conveying pressure is 140bar, the conveying speed is 0.9m/min, the extrusion temperature is 274 ℃, the cooling temperature is 14 ℃, the first roller temperature is 67 ℃, the two roller temperature is 84 ℃, the three roller temperature is 121 ℃, the four roller temperature is 218 ℃, the five roller temperature is 156 ℃, the first roller speed is 480m/min, the rear stretching stage is 5, the rear stretching ratio is 5.9, the nozzle stretching ratio is 90, the winding speed is 2832m/min, the assembly pressure is 18MPa, and the assembly service cycle is 80 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.02 dL/g; the filament number of the prepared polyester industrial yarn is 7dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.02 wt%; the breaking strength is 8cN/dtex and the elongation at break is 16 percent according to the standard test method of GB/T14344 experiment method for tensile property of 2008 chemical fiber filament.

Example 10

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.91 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 4;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively metering dried polyester chips (the water content is 50ppm after drying) and dried modified polytetrafluoroethylene (the water content is 30ppm after drying), preparing modified polytetrafluoroethylene/polyester master batches, respectively metering the dried modified polytetrafluoroethylene/polyester master batches and the dried polyester chips, mixing according to the proportion required by the finally prepared polyester industrial yarns, and feeding the polyester industrial yarns into a screw for melting; the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 14 wt%;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 286 ℃, the conveying temperature is 281 ℃, the conveying pressure is 170bar, the conveying speed is 1.1m/min, the extrusion temperature is 276 ℃, the cooling temperature is 15 ℃, the first roller temperature is 68 ℃, the two roller temperature is 86 ℃, the three roller temperature is 124 ℃, the four roller temperature is 225 ℃, the five roller temperature is 160 ℃, the first roller speed is 500m/min, the rear stretching stage is 5, the rear stretching ratio is 6, the spray nozzle stretching ratio is 170, the winding speed is 3000m/min, the assembly pressure is 20MPa, and the assembly service cycle is 75 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.01 dL/g; the filament number of the prepared polyester industrial yarn is 6dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.03 wt%; the breaking strength is 8.2cN/dtex and the elongation at break is 14 percent according to the standard test method of GB/T14344 experiment method for tensile property of 2008 chemical fiber filament.

Example 11

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.93 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 5;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively measuring the dried polyester slices (the water content is 50ppm after drying) and the dried modified polytetrafluoroethylene (the water content is 30ppm after drying), preparing modified polytetrafluoroethylene/polyester master batches, melting the dried modified polytetrafluoroethylene/polyester master batches, and mixing the melted modified polytetrafluoroethylene/polyester master batches with polyester melt according to the proportion required by the finally prepared polyester industrial yarn; the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 10 wt%;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 288 ℃, the conveying temperature is 283 ℃, the conveying pressure is 210bar, the conveying speed is 1.3m/min, the extrusion temperature is 278 ℃, the cooling temperature is 16 ℃, the first roller temperature is 69 ℃, the two roller temperature is 88 ℃, the three roller temperature is 126 ℃, the four roller temperature is 230 ℃, the five roller temperature is 163 ℃, the first roller speed is 520m/min, the rear stretching stage number is 5, the rear stretching ratio is 6.1, the spray head stretching ratio is 220, the winding speed is 3224m/min, the assembly pressure is 22MPa, and the assembly service cycle is 70 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.01 dL/g; the filament number of the prepared polyester industrial yarn is 5dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.04 wt%; the breaking strength is 8.4cN/dtex and the elongation at break is 13 percent according to the standard test method of GB/T14344 experiment method for tensile property of 2008 chemical fiber filament.

Example 12

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.94 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 5;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively measuring the dried polyester slices (the water content is 50ppm after drying) and the dried modified polytetrafluoroethylene (the water content is 30ppm after drying), preparing modified polytetrafluoroethylene/polyester master batches, melting the dried modified polytetrafluoroethylene/polyester master batches, and mixing the melted modified polytetrafluoroethylene/polyester master batches with polyester melt according to the proportion required by the finally prepared polyester industrial yarn; the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 16 wt%;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 289 ℃, the conveying temperature is 284 ℃, the conveying pressure is 260bar, the conveying speed is 1.4m/min, the extrusion temperature is 279 ℃, the cooling temperature is 17 ℃, the first roller temperature is 72 ℃, the two roller temperature is 89 ℃, the three roller temperature is 128 ℃, the four roller temperature is 235 ℃, the five roller temperature is 165 ℃, the first roller speed is 540m/min, the rear stretching stage is 5, the rear stretching ratio is 6.3, the nozzle stretching ratio is 260, the winding speed is 3402m/min, the assembly pressure is 24MPa, and the assembly service cycle is 65 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.01 dL/g; the filament number of the prepared polyester industrial yarn is 4dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.05 wt%; the breaking strength is 8.6cN/dtex and the elongation at break is 12% according to the standard test method of GB/T14344-2008 chemical fiber filament tensile property test method.

Example 13

A method for reducing the spinning temperature of polyester industrial yarns comprises the following specific steps:

(1) preparing raw materials;

the polyester is polyethylene terephthalate, and the intrinsic viscosity of the polyester melt is 0.95 dL/g; the polyester melt is free of micromolecular flow promoters;

the modified polytetrafluoroethylene is polytetrafluoroethylene nano-particles with ester groups on the surface; the polytetrafluoroethylene nanoparticles with ester groups on the surfaces are prepared by the method of example 6;

(2) after introducing modified polytetrafluoroethylene into the polyester melt, spinning according to the processing technology of polyester industrial yarns;

the introduction process is as follows: respectively measuring the dried polyester slices (the water content is 50ppm after drying) and the dried modified polytetrafluoroethylene (the water content is 30ppm after drying), preparing modified polytetrafluoroethylene/polyester master batches, melting the dried modified polytetrafluoroethylene/polyester master batches, and mixing the melted modified polytetrafluoroethylene/polyester master batches with polyester melt according to the proportion required by the finally prepared polyester industrial yarn; the content of the modified polytetrafluoroethylene in the modified polytetrafluoroethylene/polyester master batch is 20 wt%;

the processing process flow of the polyester industrial yarn is as follows: melting → conveying → metering → extruding → solidifying → stretching → sizing → winding;

the processing parameters of the polyester industrial yarn are as follows: the melting temperature is 290 ℃, the conveying temperature is 285 ℃, the conveying pressure is 300bar, the conveying speed is 1.5m/min, the extrusion temperature is 280 ℃, the cooling temperature is 17 ℃, the one-roller temperature is 75 ℃, the two-roller temperature is 90 ℃, the three-roller temperature is 130 ℃, the four-roller temperature is 240 ℃, the five-roller temperature is 170 ℃, the one-roller speed is 550m/min, the rear stretching stage is 5, the rear stretching ratio is 6.5, the nozzle stretching ratio is 300, the winding speed is 3600m/min, the assembly pressure is 25MPa, and the assembly service cycle is 60 days.

Before the conveying is started and after the extrusion is finished, the intrinsic viscosity of the polyester melt is reduced to 0.01 dL/g; the filament number of the prepared polyester industrial yarn is 3dtex, and the content of modified polytetrafluoroethylene in the polyester industrial yarn is 0.05 wt%; the breaking strength is 8.8cN/dtex and the elongation at break is 10% according to the standard test method of GB/T14344-2008 chemical fiber filament tensile property test method.