Preparation methods and applications of high-performance polyamide tire cord fabric

Abstract

This invention relates to the field of polyamide tire cord fabric technology, specifically disclosing a method for preparing high-performance polyamide tire cord fabric and its application. The preparation method includes the following steps: S1: Diethanolamine and formaldehyde are taken, stirred, heated, vacuumed under reduced pressure, cooled, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added, and stirring is continued to obtain an intermediate; S2: The intermediate, triethylamine, and acetone are taken, cooled, and triethylamine is added under nitrogen protection, stirred evenly, and a mixed solution of composite crosslinking agent and acetone is added dropwise, stirred, and the solvent is removed to obtain a heat-resistant modifier; S3: The heat stabilizer, heat-resistant modifier, and nylon particles are added to the mixed solvent, stirred evenly, ultrasonically treated under ultraviolet light, and the solvent is removed to obtain pretreated nylon particles; S4: The pretreated nylon particles and nylon particles are melt-spun to obtain high-performance nylon industrial yarn; high-performance polyamide tire cord fabric is obtained by spinning.

Description

Technical Field

[0001] This invention relates to the field of polyamide tire cord fabric technology, and specifically discloses a method for preparing high-performance polyamide tire cord fabric and its applications. Background Technology

[0002] Cord fabric is the skeleton material for rubber products such as tires. It is woven from warp and weft yarns. The warp yarns are generally high-performance nylon industrial yarns, with raw materials mainly consisting of nylon and polyester. They need to have advantages such as high strength, good wear resistance, heat resistance, aging resistance, and good dimensional stability. The weft yarns are generally cotton yarns or elastic fiber core-spun yarns.

[0003] Polyamide (PA), also known as nylon, is lightweight, wear-resistant, easy to process, and has high rigidity. It also contains numerous hydrogen bonds, resulting in good adhesion to rubber after impregnation, making it an ideal material for preparing high-performance nylon industrial yarns. However, the amide bonds and methylene groups adjacent to the amide bonds in the nylon molecular chain are unstable and may degrade upon heating, leading to performance degradation and limiting its applications. Therefore, researching a high-performance polyamide nylon industrial yarn with good heat resistance and dimensional stability, and using it to prepare a high-performance polyamide tire cord fabric, is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high-performance polyamide tire cord fabric and its application, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing high-performance polyamide tire cord fabric, comprising the following steps: S1: taking diethanolamine and formaldehyde, stirring at 40-45°C for 2-3 hours, heating to 75-80°C and vacuuming under reduced pressure, cooling to 60-65°C, adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continuing to stir for 2-3 hours to obtain an intermediate;

[0006] S2: Take the intermediate, triethylamine, and acetone, cool to 3-5℃, add triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and acetone dropwise, stir at 25-30℃ for 10-12h, remove the solvent, and obtain the heat-resistant modifier.

[0007] S3: Add heat stabilizer, heat-resistant modifier, and nylon particles to a mixed solvent (a mixed solvent of acetone and m-methylphenol, with a volume ratio of acetone to m-methylphenol of 1:4), stir evenly, and sonicate at 20-30 kHz for 1-2 hours under the illumination of a 250W UV lamp with λ=365nm. Remove the solvent to obtain pretreated nylon particles.

[0008] S4: Pretreated nylon particles and nylon particles are added together to a screw extruder for melt spinning to obtain high-performance nylon industrial yarn; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain high-performance polyamide cord fabric.

[0009] In a more optimized manner, in step S4, the mass ratio of pretreated nylon particles to nylon particles is (1-5) to (100:1000).

[0010] In a more optimized manner, in step S4, the mass ratio of pretreated nylon particles to nylon particles is (1-5) to 100.

[0011] In a more optimized manner, the preparation of the high-performance polyamide tire cord fabric refers to the prior art and specifically includes the following steps: twisting high-performance nylon industrial yarn (twisting on a straight twisting machine at a twisting speed of 10,000 rpm) as warp yarn; using cotton yarn (285 dtex) as weft yarn, weaving the fabric on an air-jet loom (using a plain weave structure at an air-jet loom speed of 600 rpm), impregnating with RFL impregnation solution (resin content of 4.5%), drying at 150°C, hot stretching and setting at 245°C for 6 min, and winding to obtain the high-performance polyamide tire cord fabric.

[0012] In a more optimized manner, the RFL impregnation solution comprises the following raw materials, by mass parts: 11 parts resorcinol, 6 parts formaldehyde, 0.3 parts sodium hydroxide, 100 parts butadiene-pyridine rubber latex, 60 parts soft water, and 11 parts 25% ammonia water.

[0013] In a more optimized manner, the preparation of the high-performance nylon industrial yarn includes the following steps: adding pretreated nylon to a screw extruder and performing melt spinning at 285-290°C to obtain high-performance nylon industrial yarn; the fineness of the high-performance nylon industrial yarn is 900-950 dtex.

[0014] More preferably, the intermediate comprises the following raw materials, in parts by mass: 5-6 parts diethanolamine, 4-5 parts formaldehyde, and 10-12 parts 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0015] The heat-resistant modifier comprises the following raw materials, in parts by weight: 30-35 parts intermediate and 9-12 parts composite crosslinking agent;

[0016] The pretreated nylon comprises the following raw materials, by mass: 10-15 parts heat-resistant modifier and 60-70 parts nylon particles.

[0017] More preferably, the composite crosslinking agent includes crosslinking agent A, crosslinking agent B, and crosslinking agent C;

[0018] The preparation of the crosslinking agent A includes the following steps: take 4-hydroxy-2,2,6,6-tetramethylpiperidine, triethylamine, and acetone, cool to 3-5°C, add triethylamine under nitrogen protection and stir evenly, add 1,3,5-benzenetricarboxyl chloride and acetone, stir at 25-30°C for 2-3 hours, remove the solvent, and obtain crosslinking agent A;

[0019] The preparation of the crosslinking agent B includes the following steps: take 4-mercapto-1-butanol, triethylamine, and acetone, cool to 3-5°C, add triethylamine under nitrogen protection and stir evenly, add 1,3,5-benzenetricarboxyl chloride and acetone, stir at 25-30°C for 2-3 hours, remove the solvent, and obtain crosslinking agent B.

[0020] The crosslinking agent C is 1,3,5-benzenetricarboxylic acid chloride.

[0021] In a more optimized manner, the mass ratio of crosslinking agent A, crosslinking agent B, and crosslinking agent C in the composite crosslinking agent is (3-5):(4-6):(1-2).

[0022] More preferably, the crosslinking agent A comprises the following raw materials, by mass parts: 5.5 to 6.5 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 9 to 10 parts of 1,3,5-benzenetricarboxyl chloride; the crosslinking agent B comprises the following raw materials, by mass parts: 3.5 to 4.2 parts of 4-mercapto-1-butanol and 9 to 10 parts of 1,3,5-benzenetricarboxyl chloride.

[0023] More preferably, the nylon particles include one or more of nylon 66, nylon 6, and nylon 56.

[0024] In a more optimized manner, the nylon particles are modified before being added to obtain double-bond modified nylon before being introduced; the preparation of the double-bond modified nylon includes the following steps: Step 1: Take nylon 66, add it to a mixed solution of formaldehyde and NaOH, stir at 80-90℃ for 2-3 hours, filter and wash to obtain N-hydroxymethyl modified nylon;

[0025] Step 2: Take N-hydroxymethyl modified nylon, add methacrylic acid solution, stir at 80-90℃ for 1-2 hours, wash and dry to obtain double bond modified nylon.

[0026] More preferably, the N-hydroxymethyl modified nylon comprises the following raw materials, by mass parts: 10 parts nylon 66, and 60-70 parts a mixed solution of formaldehyde and NaOH; wherein the concentration of formaldehyde in the mixed solution of formaldehyde and NaOH is 10-15 wt%, and the content of NaOH is 0.3-0.7 wt%.

[0027] The double-bond modified nylon comprises the following raw materials, by mass: 10 parts N-hydroxymethyl modified nylon, 80-100 parts methacrylic acid solution; wherein the methacrylic acid solution contains 30-40 wt% methacrylic acid, and the remainder is water.

[0028] In a more optimized manner, the formaldehyde and NaOH mixed solution has a formaldehyde concentration of 12 wt% and a NaOH content of 0.5 wt%; the methacrylic acid solution has a methacrylic acid content of 35 wt% and the remainder is water.

[0029] More preferably, the heat stabilizer includes potassium iodide and copper acetate in a molar ratio of 1:(1-15); the amount added accounts for 100-2500 ppm of the total weight of the raw materials.

[0030] The heat stabilizer comprises potassium iodide and copper acetate in a molar ratio of 1:7; the amount added accounts for 1000 ppm of the total weight of the raw materials.

[0031] In a more optimized manner, the high-performance polyamide cord fabric obtained by the above operation can be used as a skeleton material for rubber products.

[0032] Compared with the prior art, the beneficial effects achieved by this invention are as follows: The high-performance nylon industrial yarn includes a heat-resistant modifier and nylon modified with double bonds. The heat-resistant modifier is synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and diethanolamine as raw materials, forming an intermediate containing N and P, which has excellent heat resistance and flame retardancy. However, due to its low molecular weight, its compatibility with nylon is poor. Therefore, a composite crosslinking agent is introduced. Crosslinking agent A in the composite crosslinking agent is 1,3,5-benzenetricarboxyl chloride modified with 4-hydroxy-2,2,6,6-tetramethylpiperidine. 4-hydroxy-2,2,6,6-tetramethylpiperidine has an active hydrogen-containing group, which can provide hydrogen protons in actual operation, replacing the free radicals generated by polymer matrix aging and inhibiting chain reaction, thus greatly improving the photothermal aging resistance of nylon. Crosslinking agent B is modified with 4-mercapto-1-butanol, introducing mercapto... In subsequent pretreatment steps, the crosslinking agent A and B are pre-crosslinked with nylon containing double bonds to improve the compatibility between the heat stabilizer and the nylon matrix, increase the degree of crosslinking, reduce shrinkage, and improve stability. The proportions of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-mercapto-1-butanol, and 1,3,5-benzenetricarboxylic acid chloride need to be controlled to ensure that there are still enough acyl chloride groups in crosslinking agent A and crosslinking agent B to participate in the subsequent crosslinking reaction with intermediates. Otherwise, it will affect the structure and molecular weight of the heat stabilizer, leading to a decrease in performance. Crosslinking agent C, namely 1,3,5-benzenetricarboxylic acid chloride, is also introduced into the composite crosslinking agent. It contains three acyl chloride groups and is used to increase the branched structure of the heat stabilizer, improve dispersibility and stability, and also play a plasticizing role. The amount of crosslinking agent C added also needs to be controlled. If it is too low, insufficient branched structure will not be obtained, and if it is too high, the degree of branching will be too large, making processing difficult and reducing compatibility with nylon.

[0033] Nylon 66 was modified to obtain double-bond modified nylon. In the subsequent pretreatment steps, it was crosslinked with the thiol group in the heat stabilizer under ultraviolet light, which further improved the compatibility between the two and increased the degree of crosslinking, resulting in reduced shrinkage, improved thermal stability and aging resistance. In summary, the polyamide high-performance nylon industrial yarn prepared by this invention has the advantages of polyamide itself, while improving aging resistance, heat resistance and shrinkage resistance. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, all the following quantities are parts by weight.

[0036] Example 1: S1: Take 10 parts of nylon 66, add it to a mixed solution of 65 parts of formaldehyde and NaOH, stir at 85°C for 3 hours, filter and wash to obtain N-hydroxymethyl modified nylon; take 10 parts of N-hydroxymethyl modified nylon, add it to 90 parts of methacrylic acid solution, stir at 85°C for 2 hours to react with N-hydroxymethyl, wash and dry to obtain double bond modified nylon;

[0037] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0038] S3: Take 6 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0039] Take 4 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0040] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0041] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 1.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0042] S4: Take 32 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 9 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0043] S5: Add heat stabilizer, 12 parts heat-resistant modifier, and 65 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0044] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0045] Example 2: S1: Take 10 parts of nylon 66 and add it to a mixed solution of 65 parts of formaldehyde and NaOH. Stir at 85°C for 3 hours, filter and wash to obtain N-hydroxymethyl modified nylon; Take 10 parts of N-hydroxymethyl modified nylon and add it to 90 parts of methacrylic acid solution. Stir at 85°C for 2 hours to react with N-hydroxymethyl. Wash and dry to obtain double bond modified nylon.

[0046] S2: Take 5 parts of diethanolamine and 4 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and vacuum under reduced pressure, cool to 60℃, add 10 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0047] S3: Take 5.5 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 2 parts of triethylamine under nitrogen protection, stir until homogeneous, add 9 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 25°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0048] Take 3.5 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 2 parts of triethylamine under nitrogen protection, stir evenly, add 9 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 25°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0049] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0050] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 1.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0051] S4: Take 30 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 8 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 30 parts of acetone dropwise over 1 hour, stir at 25°C for 10 hours, remove the solvent, and obtain the heat-resistant modifier.

[0052] S5: Add heat stabilizer, 10 parts heat-resistant modifier, and 60 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0053] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0054] Example 3: S1: Take 10 parts of Nylon 66 and add it to a mixed solution of 65 parts of formaldehyde and NaOH. Stir at 85°C for 3 hours, filter and wash to obtain N-hydroxymethyl modified nylon; Take 10 parts of N-hydroxymethyl modified nylon and add it to 90 parts of methacrylic acid solution. Stir at 85°C for 2 hours to react with N-hydroxymethyl. Wash and dry to obtain double bond modified nylon.

[0055] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0056] S3: Take 6.5 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir until homogeneous, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 3 hours, remove the solvent, and obtain crosslinking agent A;

[0057] Take 4.2 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 3 hours, remove the solvent, and obtain crosslinking agent B.

[0058] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0059] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 1.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0060] S4: Take 35 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 10 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 40 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0061] S5: Add heat stabilizer, 15 parts heat-resistant modifier, and 70 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0062] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0063] Comparative Example 1 (reduced amount of crosslinking agent C, other steps are the same as in Example 1): S1: Preparation of nylon with double bond modification;

[0064] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0065] S3: Take 6 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0066] Take 4 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0067] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0068] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 0.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0069] S4: Take 32 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 9 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0070] S5: Add heat stabilizer, 12 parts heat-resistant modifier, and 65 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0071] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0072] Comparative Example 2 (increasing the amount of crosslinking agent C, the remaining steps are the same as in Example 1): S1: Preparation of nylon modified with double bonds;

[0073] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0074] S3: Take 6 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0075] Take 4 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0076] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0077] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 2.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0078] S4: Take 32 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 9 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0079] S5: Add heat stabilizer, 12 parts heat-resistant modifier, and 65 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0080] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0081] Comparative Example 3 (the preparation methods of crosslinking agent A and crosslinking agent B are changed, and the remaining steps are the same as in Example 1): Preparation of nylon with double bonds;

[0082] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0083] S3: Take 12 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0084] Take 8 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0085] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0086] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 1.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0087] S4: Take 32 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 9 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0088] S5: Add heat stabilizer, 12 parts heat-resistant modifier, and 65 parts double-bond modified nylon to 200 parts mixed solvent, stir evenly, and sonicate at 25 kHz for 2 hours under UV lamp irradiation of 250W, λ=365nm light to remove solvent and obtain pretreated nylon particles.

[0089] S6: Pretreated nylon particles and double-bond modified nylon with a mass ratio of 5:100 are added to a screw extruder and melt-spun at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0090] Comparative Example 4 (no pretreatment, the remaining methods and steps are the same as in Example 1): S1: Preparation of nylon with double bonds;

[0091] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40℃ for 3 hours, heat to 75℃ and reduce pressure to vacuum, cool to 60℃, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continue stirring for 3 hours to obtain the intermediate.

[0092] S3: Take 6 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 0.01 parts of triethylamine, and 30 parts of acetone. Cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent A;

[0093] Take 4 parts of 4-mercapto-1-butanol, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 3 parts of triethylamine under nitrogen protection, stir evenly, add 10 parts of 1,3,5-benzenetricarboxyl chloride and 40 parts of acetone, stir at 30°C for 2 hours, remove the solvent, and obtain crosslinking agent B.

[0094] 1,3,5-Benzotricarboxylic acid chloride was used as crosslinking agent C;

[0095] Mix 5 parts of crosslinking agent A, 5 parts of crosslinking agent B, and 1.5 parts of crosslinking agent C to obtain a composite crosslinking agent;

[0096] S4: Take 32 parts of intermediate, 0.01 parts of triethylamine, and 30 parts of acetone, cool to 5°C, add 9 parts of triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain the heat-resistant modifier.

[0097] S5: Heat stabilizer, 12 parts heat-resistant modifier, and 65 parts double-bond modified nylon are mixed evenly and added to a screw extruder for melt spinning at 290°C to obtain a high-performance nylon industrial yarn of 950 dtex; the high-performance nylon industrial yarn is twisted and used as warp yarn; cotton yarn is used as weft yarn, and the fabric is woven, impregnated, dried, heat-stretched and set, and wound up to obtain a high-performance polyamide tire cord fabric.

[0098] Unless otherwise specified, the experimental methods used in the above embodiments are conventional methods; the raw materials used are commercially available unless otherwise specified, and the sources of the raw materials are as follows: ethanol (CAS: 64-17-5); acetone (CAS: 67-64-1); nylon 66 (N74K, Shanghai Huicheng Biotechnology Co., Ltd.); formaldehyde (CAS: 50-00-0); NaOH (CAS: 1310-73-2); methacrylic acid (CAS: 79-41-4); diethanolamine (CAS: 111-42-2); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (9,10-dihydro- 9-Oxa-10-phosphaphenanthrene-10-oxide (Catalog No.: S46419, Shanghai Yuanye); 4-Hydroxy-2,2,6,6-Tetramethylpiperidine (CAS: 2403-88-5); Triethylamine (CAS: 121-44-8); 1,3,5-Benzotripyl chloride (CAS: 4422-95-1); 4-Mercapto-1-butanol (CAS: 14970-83-3); m-Methylphenol (CAS: 108-39-4); Resorcinol (CAS: 108-46-3); Butadiene-pyridine rubber latex (A053489, Zhengzhou Huiju Chemical Co., Ltd.); 25% ammonia water (Shanghai Pande International Trade Co., Ltd.).

[0099] Experiment: High-performance polyamide tire cord fabrics prepared in Examples 1-3 and Comparative Examples 1-4 were used; (1) The dry heat shrinkage rate (177℃, 2min) was tested according to GB / T9101-2002; (2) The heat resistance strength retention rate was tested according to GB / T 9101-2002; the specific data are shown in the table below;

[0100] Dry heat shrinkage rate / % Heat resistance strength retention rate / % Example 1 3.6 97.0 Example 2 3.7 96.3 Example 3 3.7 96.6 Comparative Example 1 4.0 90.9 Comparative Example 2 3.9 91.6 Comparative Example 3 4.2 87.1 Comparative Example 4 4.1 87.5

[0101] Conclusions: Comparative Examples 1 and 2, by altering the amount of crosslinking agent C (1,3,5-benzenetricarboxyl chloride), both showed a decrease in performance, indicating that the degree of branching of the heat-resistant modifier has a significant impact on performance. Comparative Example 3, by changing the preparation methods of crosslinking agents A and B and increasing the amounts of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 4-mercapto-1-butanol, affected the number of acyl chloride groups in crosslinking agents A and B, thus influencing the structure and molecular weight of the heat-resistant modifier and leading to a decrease in performance. Comparative Example 4, without pretreatment, showed performance inferior to the examples. In summary, the high-performance polyamide tire cord fabric prepared by this invention exhibits excellent heat resistance and shrinkage resistance.

[0102] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing high-performance polyamide tire cord fabric, characterized in that: Includes the following steps: S1: Take diethanolamine and formaldehyde, stir at 40~45℃ for 2~3h, heat to 75~80℃ and vacuum under reduced pressure, cool to 60~65℃, add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 2~3h to obtain the intermediate; S2: Take the intermediate, triethylamine, and acetone, cool to 3~5℃, add triethylamine under nitrogen protection, stir evenly, add a mixed solution of composite crosslinking agent and acetone dropwise, stir at 25~30℃ for 10~12h, remove the solvent, and obtain the heat-resistant modifier. S3: Add heat stabilizer, heat-resistant modifier, and nylon particles to a mixed solvent, stir evenly, and ultrasonically treat under ultraviolet light for 1-2 hours. Remove the solvent to obtain pretreated nylon particles. S4: Pretreated nylon particles and nylon particles are added together to a screw extruder for melt spinning to obtain high-performance nylon industrial yarn; the nylon industrial yarn is twisted and used as warp yarn, and cotton yarn is used as weft yarn for weaving; impregnation, drying, hot stretching and setting, and winding are performed to obtain high-performance polyamide tire cord fabric; in step S4, the mass ratio of pretreated nylon particles to nylon particles is (1~5):(100~1000); The composite crosslinking agent is crosslinking agent A, crosslinking agent B, and crosslinking agent C in a mass ratio of (3~5):(4~6):(1~2); The preparation of the crosslinking agent A includes the following steps: take 4-hydroxy-2,2,6,6-tetramethylpiperidine, triethylamine, and acetone, cool to 3~5℃, add triethylamine under nitrogen protection and stir evenly, add 1,3,5-benzenetricarboxyl chloride and acetone, stir at 25~30℃ for 2~3h, remove the solvent, and obtain crosslinking agent A; The preparation of the crosslinking agent B includes the following steps: taking 4-mercapto-1-butanol, triethylamine, and acetone, cooling to 3-5°C, adding triethylamine under nitrogen protection and stirring evenly, adding 1,3,5-benzenetricarboxyl chloride and acetone, stirring at 25-30°C for 2-3 hours, removing the solvent to obtain crosslinking agent B; the crosslinking agent C is 1,3,5-benzenetricarboxyl chloride; The crosslinking agent A comprises the following raw materials, in parts by mass: 5.5 to 6.5 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 9 to 10 parts of 1,3,5-benzenetricarboxyl chloride; The crosslinking agent B comprises the following raw materials, in parts by mass: 3.5 to 4.2 parts of 4-mercapto-1-butanol and 9 to 10 parts of 1,3,5-benzenetricarboxyl chloride; The nylon particles include one or more of nylon 66, nylon 6, and nylon 56, which are modified before being introduced to obtain double-bond modified nylon; the preparation of the double-bond modified nylon includes the following steps: Step 1: Take nylon particles, add them to a mixed solution of formaldehyde and NaOH, stir at 80~90℃ for 2~3h, filter and wash to obtain N-hydroxymethyl modified nylon; Step 2: Take N-hydroxymethyl modified nylon, add methacrylic acid solution, stir at 80~90℃ for 1~2 hours, wash and dry to obtain double bond modified nylon; The N-hydroxymethyl modified nylon comprises the following raw materials, by mass: 10 parts nylon particles, 60-70 parts a mixed solution of formaldehyde and NaOH; in the mixed solution of formaldehyde and NaOH, the concentration of formaldehyde is 10-15 wt%, and the content of NaOH is 0.3-0.7 wt%. The double-bond modified nylon comprises the following raw materials, by mass: 10 parts N-hydroxymethyl modified nylon, 80-100 parts methacrylic acid solution; wherein the methacrylic acid solution contains 30-40 wt% methacrylic acid, and the remainder is water.

2. The method for preparing high-performance polyamide tire cord fabric according to claim 1, characterized in that: The intermediate comprises the following raw materials, by mass parts: 5-6 parts diethanolamine, 4-5 parts formaldehyde, and 10-12 parts 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; the heat-resistant modifier comprises the following raw materials, by mass parts: 30-35 parts intermediate and 9-12 parts composite crosslinking agent. The pretreated nylon comprises the following raw materials, by mass: 10-15 parts heat-resistant modifier and 60-70 parts nylon particles.

3. The method for preparing high-performance polyamide tire cord fabric according to claim 1, characterized in that: The heat stabilizer includes potassium iodide and copper acetate in a molar ratio of 1:(1~15); the amount added accounts for 100~2500ppm of the total weight of the raw materials.

4. The high-performance polyamide cord fabric prepared by the method for preparing high-performance polyamide cord fabric according to any one of claims 1 to 3.

5. The application of the high-performance polyamide cord fabric according to claim 4 in the skeleton material of rubber products.