A nylon 66 cord fabric and its preparation method

Abstract

This application relates to the field of textile technology, and specifically discloses a nylon 66 cord fabric and a preparation method thereof. A nylon 66 cord fabric, the raw materials of which include: 60 - 80 parts of modified nylon 66 chips; 5 - 15 parts of heat-resistant additive; 2 - 5 parts of nano-aluminum oxide; 2 - 5 parts of nano-zirconium oxide; 5 - 12 parts of polyphenylene sulfide; 1 - 3 parts of silane coupling agent; 10 - 20 parts of dipping solution; the modified nylon 66 chips are obtained by modifying nylon 66 chips with tetrafluoroborate ionic liquid. The nylon 66 cord fabric of this application significantly enhances the heat resistance of the cord fabric by introducing modified nylon 66 chips and heat-resistant additives, and effectively ensures the supporting effect of the cord fabric in a high-temperature environment.

Description

Technical Field

[0001] The present application relates to the field of textile technology, and more specifically, to a nylon 66 cord fabric and a preparation method thereof. Background Art

[0002] Cord fabric is a vital skeleton material in the rubber industry and is widely used in tires, conveyor belts, high-pressure hoses and other products. Its main function is to provide mechanical support through the warp and weft interwoven fiber network to ensure the dimensional stability and service life of the product under dynamic load. As a typical representative, nylon 66 cord fabric has become the preferred reinforcement material for high-performance rubber products due to its excellent tensile strength, fatigue resistance and good adhesion to the rubber matrix. As transportation equipment develops towards high speed and heavy load, cord fabric needs to maintain long-term stability under complex working conditions, especially to resist performance degradation in high temperature environments, which puts higher requirements on material design.

[0003] In the related art, a patent application document with publication number CN107151919A discloses a graphene flame-retardant cord fabric and its preparation method, wherein the cord fabric includes the following components by mass fraction: 0.5%-10% graphene, 80%-90% slices, and 5%-19.5% dipping solution. When preparing the cord fabric, the graphene and slices are first mixed to obtain graphene composite fibers, which improve the flame retardancy and wear resistance of the fibers themselves. The composite fibers are then fed into a direct twisting machine to obtain twisted yarns, and finally woven into graphene cord fabric with excellent flame retardancy by a weaving machine. Subsequently, the graphene cord fabric is immersed in the dipping solution for dipping, drying, and stretching to obtain the graphene flame-retardant cord fabric. The cord fabric prepared by the above method has good flame retardancy and wear resistance.

[0004] Although the tire cord fabric prepared in the above technology has good flame retardant and wear resistance, the glass transition temperature and melting point of nylon 66 are relatively low, and the graphene is only combined with the slices by simple blending during the preparation process, which is easy to cause agglomeration due to van der Waals forces. The agglomerated graphene not only cannot form an effective heat conduction network, but also forms defect points in the matrix, which becomes a stress concentration source at high temperature, and then causes the mechanical properties of the tire cord fabric to drop significantly in high temperature environments. When subjected to external forces, these stress concentration defect points will be destroyed first, which will significantly reduce the breaking strength of the tire cord fabric and greatly weaken its supporting role as a tire skeleton material. Therefore, the tire cord fabric in the technology has the defect of poor heat resistance. Summary of the invention

[0005] In order to improve the heat resistance of tire cord fabric, the present application provides a nylon 66 tire cord fabric and a preparation method thereof.

[0006] The nylon 66 cord fabric provided in this application adopts the following technical solution:

[0007] A nylon 66 cord fabric, comprising raw materials in the following parts by weight:

[0008] 60 - 80 parts of modified nylon 66 chips;

[0009] 5 - 15 parts of heat - resistant additive;

[0010] 2 - 5 parts of nano - aluminum oxide;

[0011] 2 - 5 parts of nano - zirconium oxide;

[0012] 5 - 12 parts of polyphenylene sulfide;

[0013] 1 - 3 parts of silane coupling agent;

[0014] 10 - 20 parts of dipping solution;

[0015] The modified nylon 66 chips are obtained by modifying nylon 66 chips with tetrafluoroborate ionic liquid.

[0016] The effects are as follows: By modifying the nylon 66 chips, there are electrostatic and ion - dipole interactions between the cations and anions in the tetrafluoroborate ionic liquid and the nylon 66 molecular chains, which can improve the glass transition temperature and melting point of the nylon 66 chips; the good thermal conductivity of the ionic liquid forms thermal conduction channels in the nylon 66 chips, and when heated, the heat is rapidly transferred, avoiding local overheating and enhancing the overall thermal stability of the material; and the high thermal stability of the ionic liquid itself enables it to stably exist at high temperatures. By interacting with the nylon 66 molecular chains, it inhibits the thermal degradation reaction of the molecular chains, reduces breakage and decomposition, and further improves the thermal stability of the nylon 66 chips, thus significantly enhancing the heat - resistant performance of the cord fabric.

[0017] Both nano - aluminum oxide and nano - zirconium oxide have good high - temperature resistance and low thermal conductivity. They can form a heat - insulating network in the cord fabric, hinder the transfer of heat, reduce the thermal conduction rate of the cord fabric in a high - temperature environment, and reduce the influence of heat on the nylon 66 matrix, thereby improving the heat - resistant performance of the cord fabric. At the same time, nano - aluminum oxide and nano - zirconium oxide can stably exist at high temperatures without decomposition or deformation, which helps to maintain the structural stability of the cord fabric and further improve its heat - resistant performance. The synergistic effect of the two can more effectively improve the heat - resistant performance of the cord fabric, enabling it to still maintain good performance in a high - temperature environment.

[0018] Polyphenylene sulfide has a highly regular molecular structure and high crystallinity, and strong intermolecular forces, making it have excellent heat resistance. In the cord fabric, it interweaves with the nylon 66 molecular chains, enhancing the overall strength of the material, maintaining the dimensional stability of the cord fabric at high temperatures, and improving the heat - resistant performance.

[0019] In summary, through the synergistic cooperation of various raw materials, the heat resistance of the cord fabric provided by this application has been effectively improved.

[0020] Optionally, the modified nylon 66 chips are prepared by the following method:

[0021] A. Add 1-methylimidazole and 1-bromohexane to an acetonitrile solvent, react at 60 - 80 °C for 12 - 24 h to generate 1-hexyl-3-methylimidazolium bromide; dissolve 1-hexyl-3-methylimidazolium bromide in deionized water, add sodium tetrafluoroborate, and stir and react at room temperature for 6 - 8 h to obtain 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid;

[0022] B. Dissolve nylon 66 chips in formic acid, then add 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid, and stir and mix at 50 - 60 °C for 4 - 6 h to form a spinning solution;

[0023] C. Spin the spinning solution through a spinning machine, control the spinning speed at 150 - 200 m / min, and then obtain the modified nylon 66 chips after drying and washing.

[0024] By adopting the above technical solution, 1-hexyl-3-methylimidazolium bromide is dissolved in deionized water, and sodium tetrafluoroborate is added, successfully introducing tetrafluoroborate anions to form an ionic liquid with a specific cation-anion structure, laying a foundation for subsequent interaction with nylon 66 molecules. When nylon 66 chips are dissolved in formic acid and the ionic liquid is added, the long-chain alkyl and aromatic groups of the cation of the ionic liquid generate strong van der Waals forces and π-π interactions with the nylon 66 molecular chains. The van der Waals forces cause the ionic liquid and nylon 66 molecules to approach closely, and the π-π interaction further enhances this binding force because there is a structure with π electron clouds in the nylon 66 molecular chains, which undergoes a conjugation effect with the aromatic groups of the ionic liquid cation. The anion of the ionic liquid forms an ion-dipole interaction with the polar groups on the nylon 66 molecular chains. There are polar groups such as amide groups on the nylon 66 molecular chains, and the tetrafluoroborate anions are attracted to these polar groups to form stable ion-dipole bonds. This interaction greatly enhances the intermolecular force, significantly increasing the binding force between the originally relatively free nylon 66 molecular chains. In a high-temperature environment, the molecular chains need to obtain higher energy to overcome these enhanced intermolecular forces and move, which is manifested as an increase in the glass transition temperature and melting point of the cord fabric, thus significantly improving the heat resistance of the cord fabric.

[0025] Optionally, in step A, the mass ratio of 1-methylimidazole, 1-bromohexane, and the acetonitrile solvent is 1:(1 - 2):(6 - 8).

[0026] Optionally, the mass ratio of 1-hexyl-3-methylimidazolium bromide, deionized water and sodium tetrafluoroborate in step A is 1:(3 - 5):(0.5 - 1).

[0027] Optionally, the mass ratio of nylon 66 chips, formic acid and 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid in step B is 1:(3 - 6):(0.15 - 0.5).

[0028] By adopting the above technical solutions,

[0029] Optionally, the heat-resistant additive is prepared by the following method:

[0030] (1) Dissolve lignosulfonate in sodium hydroxide solution, stir and react at 80 - 100 °C for 2 - 4 h, then add maleic anhydride and a catalyst, and react at 120 - 140 °C for 4 - 6 h. After the reaction ends, a crude product solution is obtained;

[0031] (2) Adjust the pH of the crude product solution to 7 - 7.5 with hydrochloric acid, then filter, wash and dry to obtain the heat-resistant additive.

[0032] The effect is that: the bio-based heat-resistant additive obtained by the above preparation method has a polycyclic aromatic structure. There are strong π-π interaction and hydrogen bond interaction between the polycyclic aromatic structure and the nylon 66 molecular chain, which restricts the free movement of the nylon 66 molecular chain and increases the rigidity of the molecular chain. At the same time, the bio-based additive can form a stable carbon layer at high temperature, playing a role in heat insulation and preventing oxygen from entering, thereby improving the thermal stability of the cord fabric.

[0033] Optionally, the catalyst in step (1) is any one of dimethylaminopyridine, p-toluenesulfonic acid, and triethylamine.

[0034] The effect is that: the above catalyst can promote the esterification reaction between lignosulfonate and maleic anhydride, making the reaction proceed faster and more fully, generating more product structures with heat-resistant functions, and further improving the heat resistance of the cord fabric.

[0035] Optionally, the mass ratio of lignosulfonate, sodium hydroxide solution, maleate and catalyst in step (1) is 1:(5 - 8):(0.2 - 0.4):(0.05 - 0.1).

[0036] Optionally, the dipping solution components include resorcinol, formaldehyde and styrene-butadiene-pyridine latex; the mass ratio of resorcinol, formaldehyde and styrene-butadiene-pyridine latex is (1 - 3):(1 - 3):(10 - 20).

[0037] Its effects are as follows: Resorcinol, formaldehyde, and styrene-butadiene-pyridine latex form a stable network structure through a polycondensation reaction at a specific ratio, enhancing the bonding force between the cord fabric fibers, improving the overall strength and fatigue resistance of the cord fabric, and enabling it to better play a supporting role as a tire skeleton material.

[0038] This application also provides a method for preparing nylon 66 cord fabric, adopting the following technical solution:

[0039] A method for preparing nylon 66 cord fabric includes the following steps:

[0040] S1. Thoroughly mix modified nylon 66 chips, heat-resistant additives, nano-aluminum oxide, nano-zirconium oxide, polyphenylene sulfide, and silane coupling agent in a high-speed mixer at a mixing speed of 800 - 1200 r / min for 10 - 15 min, and then add the mixture to a screw extruder for melt blending and extrusion granulation to obtain composite masterbatch;

[0041] S2. Spin the composite masterbatch through a spinning machine at a spinning temperature of 270 - 290 °C and a spinning speed of 3000 - 4000 m / min to obtain nascent fibers, and perform stretching and heat setting on the nascent fibers to obtain modified nylon fiber filaments;

[0042] S3. Weave the modified nylon fiber filaments into cord fabric using a knitting machine, then immerse the cord fabric in the dipping solution for 3 - 5 h, take it out and dry it at 120 - 150 °C, and then perform stretching and setting at 180 - 200 °C to obtain nylon 66 cord fabric.

[0043] In summary, this application has the following beneficial effects:

[0044] 1. By modifying the nylon 66 chips in this application, there are electrostatic and ion-dipole interactions between the cations and anions in the tetrafluoroborate ionic liquid and the nylon 66 molecular chains, thereby being able to increase the glass transition temperature and melting point of the nylon 66 chips; the good thermal conductivity of the ionic liquid forms heat conduction channels in the nylon 66 chips, enabling rapid heat transfer when heated, avoiding local overheating, and enhancing the overall thermal stability of the material; and the high thermal stability of the ionic liquid itself enables it to stably exist at high temperatures, and by interacting with the nylon 66 molecular chains, it inhibits the thermal degradation reaction of the molecular chains, reduces breakage and decomposition, and further improves the thermal stability of the nylon 66 chips, thus significantly enhancing the heat resistance of the cord fabric.

[0045] 2. In this application, nano-aluminum oxide and nano-zirconium oxide are added. Both nano-aluminum oxide and nano-zirconium oxide have good high-temperature resistance and low thermal conductivity. They can form a heat-insulating network in the cord fabric, hinder the transfer of heat, reduce the heat conduction rate of the cord fabric in a high-temperature environment, reduce the influence of heat on the nylon 66 matrix, and thus improve the heat resistance of the cord fabric. At the same time, nano-aluminum oxide and nano-zirconium oxide can stably exist at high temperatures without decomposition or deformation, which helps to maintain the structural stability of the cord fabric and further improve its heat resistance. The synergistic effect of the two can more effectively improve the heat resistance of the cord fabric, enabling it to still maintain good performance in a high-temperature environment.

[0046] 3. In this application, polyphenylene sulfide is added and melt-blended with modified nylon 66 chips. Polyphenylene sulfide has a highly regular molecular structure and high crystallinity, and strong intermolecular forces, making it have excellent heat resistance. In the cord fabric, it interweaves with the nylon 66 molecular chains, enhancing the overall strength of the material, maintaining the dimensional stability of the cord fabric at high temperatures, and improving the heat resistance. Detailed implementation mode

[0047] The following further elaborates on this application with reference to examples.

[0048] Preparation example of modified nylon 66 chips

[0049] Preparation example 1

[0050] The modified nylon 66 chips are prepared by the following method:

[0051] A. Add 10 kg of 1-methylimidazole and 10 kg of 1-bromohexane to 60 kg of acetonitrile solvent, react at 60 °C for 24 h to generate 1-hexyl-3-methylimidazolium bromide; dissolve 10 kg of 1-hexyl-3-methylimidazolium bromide in 30 kg of deionized water, then add 5 kg of sodium tetrafluoroborate, and stir and react at room temperature for 6 h to obtain 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid;

[0052] B. Dissolve 100 kg of nylon 66 chips in 300 kg of formic acid, then add 15 kg of 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid, and stir and mix at 50 °C for 6 h to form a spinning solution;

[0053] C. Spin the spinning solution through a spinning machine, control the spinning speed at 150 m / min, the aperture of the spinning machine nozzle is 0.1 mm, and after forming, dry and wash to obtain the modified nylon 66 chips.

[0054] Preparation example 2

[0055] The modified nylon 66 chips are prepared by the following method:

[0056] A. Add 10 kg of 1-methylimidazole and 15 kg of 1-bromohexane to 70 kg of acetonitrile solvent, and react at 70 °C for 18 h to produce 1-hexyl-3-methylimidazolium bromide; dissolve 10 kg of 1-hexyl-3-methylimidazolium bromide in 40 kg of deionized water, then add 8 kg of sodium tetrafluoroborate, and stir and react at room temperature for 7 h to obtain 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid;

[0057] B. Dissolve 100 kg of nylon 66 chips in 500 kg of formic acid, then add 40 kg of 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid, and stir and mix at 55 °C for 5 h to form a spinning solution;

[0058] C. Spin the spinning solution through a spinning machine, control the spinning speed at 170 m / min, the aperture of the spinning machine nozzle is 0.1 mm, and after forming, obtain modified nylon 66 chips after drying and washing.

[0059] Preparation Example 3

[0060] The modified nylon 66 chips are prepared by the following method:

[0061] A. Add 10 kg of 1-methylimidazole and 20 kg of 1-bromohexane to 80 kg of acetonitrile solvent, and react at 80 °C for 12 h to produce 1-hexyl-3-methylimidazolium bromide; dissolve 10 kg of 1-hexyl-3-methylimidazolium bromide in 50 kg of deionized water, then add 10 kg of sodium tetrafluoroborate, and stir and react at room temperature for 8 h to obtain 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid;

[0062] B. Dissolve 100 kg of nylon 66 chips in 600 kg of formic acid, then add 50 kg of 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid, and stir and mix at 60 °C for 4 h to form a spinning solution;

[0063] C. Spin the spinning solution through a spinning machine, control the spinning speed at 200 m / min, the aperture of the spinning machine nozzle is 0.1 mm, and after forming, obtain modified nylon 66 chips after drying and washing.

[0064] Preparation Example 4

[0065] The modified nylon 66 chips are modified by dicyandiamide salt ionic liquid in this preparation example. Specifically, the following steps are adopted:

[0066] A. Dissolve 100 kg of nylon 66 chips in 600 kg of formic acid, then add 50 kg of dicyandiamide 1-butyl-3-methylimidazolium ionic liquid, and stir and mix at 60 °C for 4 h to form a spinning solution;

[0067] B. Spin the spinning solution through a spinning machine, control the spinning speed at 200 m / min, the aperture of the spinning machine nozzle is 0.1 mm, and after forming, obtain modified nylon 66 chips through drying and washing.

[0068] Preparation example of heat-resistant additive

[0069] Preparation example 5

[0070] The heat-resistant additive is prepared by the following method:

[0071] (1) Dissolve 10 kg of lignosulfonate in 50 kg of sodium hydroxide solution with a mass concentration of 15%, then stir and react at 80 °C for 2 h, then add 2 kg of maleic anhydride and 0.5 kg of dimethylaminopyridine, and react at 120 °C for 4 h. After the reaction ends, obtain a crude product solution;

[0072] (2) Adjust the pH of the crude product solution to 7 - 7.5 with hydrochloric acid, then filter, take the solid phase, wash it three times with deionized water and dry it to obtain the heat-resistant additive.

[0073] Preparation example 6

[0074] The heat-resistant additive is prepared by the following method:

[0075] (1) Dissolve 10 kg of lignosulfonate in 70 kg of sodium hydroxide solution with a mass concentration of 15%, then stir and react at 90 °C for 3 h, then add 3 kg of maleic anhydride and 0.8 kg of p-toluenesulfonic acid, and react at 130 °C for 5 h. After the reaction ends, obtain a crude product solution;

[0076] (2) Adjust the pH of the crude product solution to 7 - 7.5 with hydrochloric acid, then filter, take the solid phase, wash it three times with deionized water and dry it to obtain the heat-resistant additive.

[0077] Preparation example 7

[0078] The heat-resistant additive is prepared by the following method:

[0079] (1)Dissolve 10 kg of lignosulfonate in 80 kg of sodium hydroxide solution with a mass concentration of 15%, then stir and react at 100 °C for 4 h, then add 4 kg of maleic anhydride and 1 kg of triethylamine, and react at 140 °C for 6 h. After the reaction ends, obtain a crude product solution;

[0080] (2) Adjust the pH of the crude product solution to 7 - 7.5 with hydrochloric acid, then filter, wash the solid phase three times with deionized water and dry it to obtain the heat-resistant additive.

[0081] Example

[0082] Example 1

[0083] A nylon 66 cord fabric, the raw material components and their dosages are shown in Table 1. Among them, the modified nylon 66 chips are the modified nylon 66 chips prepared in Preparation Example 1; the heat-resistant additive is the heat-resistant additive prepared in Preparation Example 5; the number-average molecular weight of polyphenylene sulfide is 50,000; the silane coupling agent is of KH172 type; the dipping solution is composed of resorcinol, formaldehyde and styrene-butadiene-pyridine latex mixed in a mass ratio of 1:1:10.

[0084] A preparation method of nylon 66 cord fabric includes the following steps:

[0085] S1. Thoroughly mix the modified nylon 66 chips, heat-resistant additive, nano-aluminum oxide, nano-zirconium oxide, polyphenylene sulfide and silane coupling agent in a high-speed mixer, the mixing speed is 800 r / min, the mixing time is 10 min, then add the mixture into a screw extruder for melt blending, the temperature of the screw extruder is set at 260 °C, the screw speed is 200 r / min, and pelletize by extrusion to obtain composite masterbatch;

[0086] S2. Spin the composite masterbatch through a spinning machine, the spinning temperature is 270 °C, the spinning speed is 3000 m / min to obtain nascent fibers, and perform stretching and heat setting on the nascent fibers to obtain modified nylon fiber filaments;

[0087] S3. Weave the modified nylon fiber filaments into cord fabric by a knitting machine, then immerse the cord fabric in the dipping solution for 3 h, take it out and dry it at 120 °C, and then perform stretching and setting at 180 °C to obtain nylon 66 cord fabric.

[0088] Example 2

[0089] A nylon 66 cord fabric, the raw material components and their dosages are shown in Table 1. Among them, the modified nylon 66 chips are the modified nylon 66 chips prepared in Preparation Example 2; the heat-resistant additive is the heat-resistant additive prepared in Preparation Example 5; the number-average molecular weight of polyphenylene sulfide is 50,000; the silane coupling agent is of KH172 type; the dipping solution is composed of resorcinol, formaldehyde and styrene-butadiene-pyridine latex mixed in a mass ratio of 2:2:15.

[0090] A preparation method of nylon 66 cord fabric includes the following steps:

[0091] S1. Thoroughly mix the modified polyamide 66 chips, heat-resistant additive, nano-aluminum oxide, nano-zirconium oxide, polyphenylene sulfide, and silane coupling agent in a high-speed mixer at a mixing speed of 1000 r / min for 13 minutes. Then, add the mixture to a screw extruder for melt blending. Set the temperature of the screw extruder to 270 °C and the screw speed to 250 r / min to obtain composite masterbatch by extrusion granulation.

[0092] S2. Spun the composite masterbatch through a spinning machine at a spinning temperature of 280 °C and a spinning speed of 3500 m / min to obtain nascent fibers, and then perform stretching and heat setting on the nascent fibers to obtain modified polyamide fibers.

[0093] S3. Weave the modified polyamide fibers into cord fabric using a knitting machine, then immerse the cord fabric in the dipping solution for 4 hours, take it out and dry it at 130 °C, and then perform stretching and setting at 190 °C to obtain polyamide 66 cord fabric.

[0094] Example 3

[0095] A polyamide 66 cord fabric, the raw material components and dosages of which are shown in Table 1. Among them, the modified polyamide 66 chips are the modified polyamide 66 chips prepared in Preparation Example 3; the heat-resistant additive is the heat-resistant additive prepared in Preparation Example 5; the number-average molecular weight of polyphenylene sulfide is 50000; the silane coupling agent is of KH172 type; the dipping solution is composed of resorcinol, formaldehyde, and styrene-butadiene-pyridine latex mixed in a mass ratio of 3:3:20.

[0096] A preparation method of polyamide 66 cord fabric, comprising the following steps:

[0097] S1. Thoroughly mix the modified polyamide 66 chips, heat-resistant additive, nano-aluminum oxide, nano-zirconium oxide, polyphenylene sulfide, and silane coupling agent in a high-speed mixer at a mixing speed of 1200 r / min for 15 minutes. Then, add the mixture to a screw extruder for melt blending. Set the temperature of the screw extruder to 280 °C and the screw speed to 300 r / min to obtain composite masterbatch by extrusion granulation.

[0098] S2. Spun the composite masterbatch through a spinning machine at a spinning temperature of 290 °C and a spinning speed of 4000 m / min to obtain nascent fibers, and then perform stretching and heat setting on the nascent fibers to obtain modified polyamide fibers.

[0099] S3. Weave the modified polyamide fibers into cord fabric using a knitting machine, then immerse the cord fabric in the dipping solution for 5 hours, take it out and dry it at 150 °C, and then perform stretching and setting at 200 °C to obtain polyamide 66 cord fabric.

[0100] Table 1 Raw material components and dosages (kg) of cord fabric in Examples 1-3

[0101]

[0102] Example 4

[0103] A nylon 66 cord fabric, different from Example 1 in that in this example, the heat-resistant additive is the heat-resistant additive prepared in Preparation Example 6.

[0104] Example 5

[0105] A nylon 66 cord fabric, different from Example 1 in that in this example, the heat-resistant additive is the heat-resistant additive prepared in Preparation Example 7.

[0106] Example 6

[0107] A nylon 66 cord fabric, different from Example 1 in that in this example, the heat-resistant additive is an equal amount of fatty amine polyoxyethylene ether.

[0108] Comparative Example

[0109] Comparative Example 1

[0110] A nylon 66 cord fabric, different from Example 1 in that in this comparative example, an equal amount of unmodified nylon 66 chips are used instead of the modified nylon 66 chips.

[0111] Comparative Example 2

[0112] A nylon 66 cord fabric, different from Example 1 in that in this comparative example, the modified nylon 66 chips are the modified nylon 66 chips prepared in Preparation Example 4.

[0113] Comparative Example 3

[0114] A nylon 66 cord fabric, different from Example 1 in that in this comparative example, nano-aluminum oxide is not added, and nano-zirconium oxide is used to make up for the amount of nano-aluminum oxide.

[0115] Comparative Example 4

[0116] A nylon 66 cord fabric, different from Example 1 in that in this comparative example, nano-zirconium oxide is not added, and nano-aluminum oxide is used to make up for the amount of nano-zirconium oxide.

[0117] Performance detection test

[0118] Test samples: Nylon 66 cord fabrics of Examples 1-6 and Comparative Examples 1-4.

[0119] Detection method:

[0120] 1. Normal temperature detection

[0121] Place the specimen in a thermo-hygrostat chamber, adjust the temperature to 25 °C and the relative humidity to 65%, and place it for 24 hours to allow the specimen to reach an equilibrium state. Then install the pretreated specimen on an electronic universal testing machine and conduct a tensile test at a tensile speed of 50 mm / min. Record the maximum force value at the moment of specimen fracture, which is the breaking strength. Each specimen is tested 3 times repeatedly, and the average value is taken as the breaking strength of this group of cord fabrics at normal temperature. The results are shown in Table 2.

[0122] 2. Tests under high-temperature conditions

[0123] Put the specimen into a high-temperature oven, set the oven temperature to 180 °C, and keep it warm for 2 hours to ensure that the specimen is evenly heated at high temperature. Quickly take out the specimen after high-temperature treatment and immediately install it on an electronic universal testing machine to conduct a tensile test at a tensile speed of 50 mm / min. Record the breaking strength. Similarly, each specimen is tested 3 times repeatedly, and the average value is taken. The results are shown in Table 2.

[0124] 3. Calculate the loss rate of the breaking strength under high-temperature conditions relative to that at normal temperature. The lower the loss rate, the better the heat resistance of the sample. The results are shown in Table 2.

[0125] Table 2 Test results

[0126]

[0127] The breaking strengths of Examples 1-5 at normal temperature (25 °C) are similar, all around 320 N - 325 N, and the breaking strengths at high temperature (180 °C) are also all around 313 N - 316 N. This indicates that under the formulation and preparation process of this invention, the performance of the cord fabric is relatively stable. Under high-temperature conditions, the loss rates of the breaking strength of the cord fabric are all relatively low, between 2.37% - 2.68%, indicating that the cord fabrics prepared in Examples 1-5 of this application have good heat resistance.

[0128] The breaking strength of Example 6 at normal temperature is 320.6 N, which is similar to other examples, but at high temperature it is 298.3 N, significantly lower than other examples. The breaking strength loss rate of Example 6 is 6.96%, much higher than other examples. This is because in Example 6, an equal amount of fatty amine polyoxyethylene ether is used to replace the heat-resistant additive prepared in Preparation Example 5. It shows that the enhancing effect of fatty amine polyoxyethylene ether on the heat resistance of the cord fabric is not as good as the heat-resistant additive provided in the preparation examples of this application.

[0129] Compared with Example 1, in Comparative Example 1, an equal amount of unmodified nylon 66 chips was used to replace the modified nylon 66 chips. Its breaking strength at normal temperature was 305.3 N, lower than 323.6 N of Example 1. Its breaking strength at high temperature was 223.7 N, and the breaking strength loss rate was as high as 26.8%. This is because the glass transition temperature and melting point of unmodified nylon 66 chips are relatively low, and there is no interaction between ionic liquid and molecular chains to inhibit the thermal degradation reaction. At high temperature, the molecular chains are prone to movement and breakage, resulting in a significant decrease in the heat resistance of the cord fabric.

[0130] In Comparative Example 2, the modified nylon 66 chips prepared in Preparation Example 4 were selected as the modified nylon 66 chips, and dicyandiamide salt ionic liquid was used to modify the nylon 66 chips. Its breaking strength at normal temperature was 309.3 N, and at high temperature was 232.6 N. The breaking strength loss rate was 24.8%, higher than that of Example 1. This shows that the interaction between dicyandiamide salt ionic liquid and nylon 66 molecular chains is not as good as that of 1-hexyl-3-methylimidazolium tetrafluoroborate ionic liquid, and it cannot well improve the glass transition temperature and melting point of nylon 66 chips, nor can it effectively inhibit the thermal degradation reaction of molecular chains, resulting in the heat resistance of the cord fabric being inferior to that of the cord fabric in Example 1.

[0131] In Comparative Example 3, nano-aluminum oxide was not added, and the dosage was supplemented with nano-zirconia; in Comparative Example 4, nano-zirconia was not added, and the dosage was supplemented with nano-aluminum oxide. Their breaking strengths at high temperature were 286.5 N and 278.9 N respectively, and the breaking strength loss rates were 9.22% and 12.4% respectively, both higher than those of Examples 1-5. This shows that nano-aluminum oxide and nano-zirconia have a synergistic effect in the cord fabric, jointly forming a heat insulation network to hinder heat transfer and maintain structural stability. The lack of either one will cause the heat resistance of the cord fabric to decline.

[0132] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A nylon 66 cord fabric, characterized in that, It includes raw materials in the following parts by weight: 60 - 80 parts of modified polyamide 66 chips; 5 - 15 parts of heat - resistant additive; 2 - 5 parts of nano - alumina; 2 - 5 parts of nano - zirconia; 5 - 12 parts of polyphenylene sulfide; 1 - 3 parts of silane coupling agent; 10 - 20 parts of dipping solution; The modified polyamide 66 chips are prepared by the following method: A. Add 1 - methylimidazole and 1 - bromohexane into an acetonitrile solvent, react at 60 - 80 °C for 12 - 24 h to generate 1 - hexyl - 3 - methylimidazolium bromide; dissolve 1 - hexyl - 3 - methylimidazolium bromide in deionized water, add sodium tetrafluoroborate, and stir - react at room temperature for 6 - 8 h to obtain 1 - hexyl - 3 - methylimidazolium tetrafluoroborate ionic liquid; B. Dissolve polyamide 66 chips in formic acid, then add 1 - hexyl - 3 - methylimidazolium tetrafluoroborate ionic liquid, and stir - mix at 50 - 60 °C for 4 - 6 h to form a spinning solution; C. Spin - form the spinning solution through a spinning machine, control the spinning speed at 150 - 200 m / min, and then obtain the product after drying and washing; The heat - resistant additive is prepared by the following method: (1) Dissolve lignosulfonate in a sodium hydroxide solution, stir - react at 80 - 100 °C for 2 - 4 h, then add maleic anhydride and a catalyst, and react at 120 - 140 °C for 4 - 6 h to obtain a crude product solution; (2) Adjust the pH of the crude product solution to 7 - 7.5 with hydrochloric acid, then filter, wash and dry to obtain the product.

2. The nylon 66 cord fabric according to claim 1, wherein: In step A, the mass ratio of 1 - methylimidazole, 1 - bromohexane and acetonitrile solvent is 1:(1 - 2):(6 - 8).

3. The nylon 66 cord fabric according to claim 1, characterized in that: In step A, the mass ratio of 1 - hexyl - 3 - methylimidazolium bromide, deionized water and sodium tetrafluoroborate is 1:(3 - 5):(0.5 - 1).

4. The nylon 66 cord fabric according to claim 1, characterized in that: In step B, the mass ratio of polyamide 66 chips, formic acid and 1 - hexyl - 3 - methylimidazolium tetrafluoroborate ionic liquid is 1:(3 - 6):(0.15 - 0.5).

5. The nylon 66 cord fabric according to claim 1, characterized in that: In step (1), the catalyst is any one of dimethylaminopyridine, p - toluenesulfonic acid, and triethylamine.

6. A nylon 66 cord fabric according to claim 1, characterized in that: In step (1), the mass ratio of lignosulfonate, sodium hydroxide solution, maleic anhydride and catalyst is 1:(5 - 8):(0.2 - 0.4):(0.05 - 0.1).

7. A nylon 66 cord fabric according to claim 1, characterized in that: The dipping solution components include resorcinol, formaldehyde and styrene - butadiene - pyridine latex; the mass ratio of resorcinol, formaldehyde and styrene - butadiene - pyridine latex is (1 - 3):(1 - 3):(10 - 20).

8. A method for preparing the nylon 66 cord fabric according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Thoroughly mix the modified polyamide 66 chips, heat - resistant additive, nano - alumina, nano - zirconia, polyphenylene sulfide and silane coupling agent in a high - speed mixer, with a mixing speed of 800 - 1200 r / min and a mixing time of 10 - 15 min, then add the mixture into a screw extruder for melt - blending and extrusion - granulation to obtain a composite masterbatch; S2. Spun the composite masterbatch by a spinning machine at a spinning temperature of 270 - 290 °C and a spinning speed of 3000 - 4000 m / min to obtain nascent fibers, and then carried out stretching and heat setting on the nascent fibers to obtain modified polyamide fiber filaments; S3. Wove the modified polyamide fiber filaments into cord fabric by a knitting machine, then immersed the cord fabric in the dipping solution for 3 - 5 h, dried it at 120 - 150 °C after taking it out, and then carried out stretching and setting at 180 - 200 °C to obtain nylon 66 cord fabric.

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