Preparation method and application of high-performance polyamide cord fabric

Abstract

The invention relates to the technical field of polyamide cord fabrics, and particularly discloses a preparation method and application of a high-performance polyamide cord fabric. The preparation method comprises the following steps: S1, taking diethanol amine and formaldehyde, stirring, heating, vacuumizing under reduced pressure, cooling, adding 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and continuously stirring to obtain an intermediate; s2, taking the intermediate, triethylamine and acetone, cooling, adding triethylamine under the protection of nitrogen, uniformly stirring, dropwise adding a mixed solution of a composite cross-linking agent and acetone, stirring, and removing a solvent to obtain a heat-resistant modifier; s3, adding a heat stabilizer, a heat-resistant modifier and nylon particles into a mixed solvent, uniformly stirring, carrying out ultrasonic treatment under ultraviolet irradiation, and removing the solvent to prepare pretreated nylon particles; s4, carrying out melt spinning on the pretreated nylon particles and nylon particles to obtain high-performance nylon industrial yarns; and spinning to obtain the high-performance polyamide cord fabric.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide cord fabrics, and specifically discloses a preparation method and application of high-performance polyamide cord fabrics. Background Art

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

[0003] Polyamide (PA), also called nylon, has the characteristics of light weight, wear resistance, easy processing, high rigidity, etc. It contains a lot of hydrogen bonds and has good adhesion to rubber after dipping. It is an ideal material for preparing high-performance nylon industrial yarn. However, the amide bond and the methylene group adjacent to the amide bond in the nylon molecular chain are unstable and may degrade when heated, resulting in reduced performance, which limits its application. In summary, it is of great significance to study a polyamide high-performance nylon industrial yarn with good heat resistance and good dimensional stability, and use it to prepare a high-performance polyamide cord fabric. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of high-performance polyamide cord fabric to solve the problems raised in the prior art.

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

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

[0007] S3: adding a heat stabilizer, a heat-resistant modifier and nylon particles into a mixed solvent (a mixed solvent of acetone and m-cresol, with a volume ratio of acetone to m-cresol of 1:4), stirring the mixture evenly, and subjecting the mixture to ultrasonic treatment at 20 to 30 kHz for 1 to 2 hours under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0008] S4: adding the pretreated nylon particles and the nylon particles together into a screw extruder for melt spinning to obtain high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

[0009] More optimally, in step S4, the mass ratio of the pretreated nylon particles to the nylon particles is (1-5)-(100:1000).

[0010] More optimally, in step S4, the mass ratio of the pretreated nylon particles to the nylon particles is (1-5)-100.

[0011] More optimally, the preparation of the high-performance polyamide cord fabric refers to the existing technology, specifically including the following steps: twisting the high-performance nylon industrial yarn (twisting on a direct twisting machine with a twisting speed of 10,000 rpm) as the warp yarn; using cotton yarn (285dtex) as the weft yarn, weaving on a jet loom (using a plain weave structure and a jet loom speed of 600 rpm), using RFL dipping solution for dipping (with an attached glue amount of 4.5%), drying at 150°C, heat stretching at 245°C for 6 minutes, and winding to obtain a high-performance polyamide cord fabric.

[0012] More optimally, the RFL dipping solution includes the following raw materials, calculated by mass: 11 parts of resorcinol, 6 parts of formaldehyde, 0.3 parts of sodium hydroxide, 100 parts of butylpyrrolidone rubber latex, 60 parts of soft water, and 11 parts of 25% ammonia water.

[0013] More optimally, 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 optimally, the intermediate comprises the following raw materials, by weight: 5 to 6 parts of diethanolamine, 4 to 5 parts of formaldehyde, and 10 to 12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0015] The heat-resistant modifier comprises the following raw materials, calculated by weight: 30 to 35 parts of an intermediate, 9 to 12 parts of a composite cross-linking agent;

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

[0017] More optimally, the composite cross-linking agent includes cross-linking agent A, cross-linking agent B, and cross-linking agent C;

[0018] The preparation of the cross-linking agent A comprises the following steps: taking 4-hydroxy-2,2,6,6-tetramethylpiperidine, triethylamine and acetone, cooling to 3-5°C, adding triethylamine and stirring evenly under nitrogen protection, adding 1,3,5-benzenetricarboxylic acid chloride and acetone, stirring at 25-30°C for 2-3h, and removing the solvent to obtain the cross-linking agent A;

[0019] The preparation of the crosslinking agent B comprises the following steps: taking 4-mercapto-1-butanol, triethylamine and acetone, cooling to 3-5° C., adding triethylamine and stirring evenly under nitrogen protection, adding 1,3,5-benzenetricarboxylic acid chloride and acetone, stirring at 25-30° C. for 2-3 hours, and removing the solvent to obtain the crosslinking agent B;

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

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

[0022] More optimally, the cross-linking agent A comprises the following raw materials, calculated 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-benzenetricarboxylic acid chloride; the cross-linking agent B comprises the following raw materials, calculated by mass: 3.5 to 4.2 parts of 4-mercapto-1-butanol and 9 to 10 parts of 1,3,5-benzenetricarboxylic acid chloride.

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

[0024] More optimally, the nylon particles are modified before being added to obtain double bond-modified nylon and then introduced; the preparation of the double bond-modified nylon comprises the following steps: Step 1: Take nylon 66, add it to a mixed solution of formaldehyde and NaOH, stir at 80-90°C for 2-3h, 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°C for 1-2h, wash and dry to obtain double bond modified nylon.

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

[0027] The double bond-containing modified nylon comprises the following raw materials, calculated by weight: 10 parts of N-hydroxymethyl modified nylon, 80-100 parts of methacrylic acid solution; in the methacrylic acid solution, the methacrylic acid content is 30-40wt%, and the rest is water.

[0028] More optimally, in the mixed solution of formaldehyde and NaOH, the concentration of formaldehyde is 12wt%, and the content of NaOH is 0.5wt%; in the methacrylic acid solution, the content of methacrylic acid is 35wt%, and the rest is water.

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

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

[0031] More optimally, the high-performance polyamide cord fabric obtained by the above operation can be applied to the skeleton material of rubber products.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the high-performance nylon industrial yarn includes a heat-resistant modifier and a double-bond-modified nylon; the heat-resistant modifier uses 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and diethanolamine as raw materials to synthesize an intermediate containing N and P, and has good heat resistance and flame retardancy, but due to its low molecular weight, its compatibility with nylon is poor; therefore, a composite cross-linking agent is introduced, and the cross-linking agent A in the composite cross-linking agent is 1,3,5-benzenetricarboxylic acid chloride modified with 4-hydroxy-2,2,6,6-tetramethylpiperidine, and 4-hydroxy-2,2,6,6-tetramethylpiperidine has an active hydrogen-containing group, which can provide hydrogen protons in actual action, replace the polymer matrix and combine with the free radicals generated by polymer aging, inhibit the chain reaction, and can greatly improve the light and heat aging resistance of nylon; the cross-linking agent B is modified with 4-mercapto-1-butanol, and mercapto is introduced. The base is pre-crosslinked with the nylon containing double bonds during the subsequent pretreatment step to improve the compatibility of the heat-resistant stabilizer with the nylon matrix, and also improve the crosslinking degree, reduce the shrinkage rate and improve the stability; the addition ratio of 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-mercapto-1-butanol and 1,3,5-benzenetricarboxylic acid chloride needs to be controlled to ensure that there are still enough acyl chloride groups in the crosslinker A and the crosslinker B to participate in the subsequent crosslinking reaction with the intermediate, otherwise it will affect the structure and molecular weight of the heat-resistant stabilizer and cause the performance to decline; the composite crosslinker also introduces a crosslinker C, i.e., 1,3,5-benzenetricarboxylic acid chloride, which contains three acyl chloride groups, to increase the branched structure of the heat-resistant stabilizer, improve the dispersibility and stability, and also play a role in plasticization; the addition amount of the crosslinker C also needs to be controlled, if it is too low, sufficient branched structure cannot be obtained, and if it is too high, the degree of branching is large, the processing is difficult and the compatibility with nylon is reduced.

[0033] Nylon 66 is modified to obtain double-bond modified nylon, which is cross-linked with the thiol group in the heat-resistant stabilizer under ultraviolet light in the pretreatment of the subsequent step, so as to further improve the compatibility between the two and increase the degree of cross-linking, thereby reducing the shrinkage rate and improving the thermal stability and aging resistance. In summary, the polyamide high-performance nylon industrial yarn prepared by the present invention has the advantages of polyamide itself, and at the same time improves the aging resistance, heat resistance and shrinkage resistance. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The following parts are by mass unless otherwise specified;

[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 90 parts of methacrylic acid solution, stir at 85°C for 2 hours, react with N-hydroxymethyl, wash and dry to obtain double bond-containing modified nylon;

[0037] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker B;

[0040] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0043] S5: adding a heat stabilizer, 12 parts of a heat-resistant modifier, and 65 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0044] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

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

[0046] S2: Take 5 parts of diethanolamine and 4 parts of formaldehyde, stir at 40°C for 3h, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 10 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3h to obtain an 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 evenly, add 9 parts of 1,3,5-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 25°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 25°C for 2h, remove the solvent, and obtain crosslinker B;

[0049] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 30 parts of acetone dropwise over 1 hour, stir at 25°C for 10 hours, remove the solvent, and obtain a heat-resistant modifier;

[0052] S5: adding a heat stabilizer, 10 parts of a heat-resistant modifier, and 60 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0053] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

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

[0055] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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 evenly, add 10 parts of 1,3,5-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 3h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 3h, remove the solvent, and obtain crosslinker B;

[0058] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 40 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0061] S5: adding a heat stabilizer, 15 parts of a heat-resistant modifier, and 70 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0062] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

[0063] Comparative Example 1 (reducing the amount of cross-linking agent C added, and the remaining method steps are consistent with Example 1): S1: preparing double bond-containing modified nylon;

[0064] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker B;

[0067] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0070] S5: adding a heat stabilizer, 12 parts of a heat-resistant modifier, and 65 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0071] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

[0072] Comparative Example 2 (increasing the amount of crosslinking agent C added, and the remaining method steps are consistent with Example 1): S1: preparing double bond-containing modified nylon;

[0073] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker B;

[0076] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0079] S5: adding a heat stabilizer, 12 parts of a heat-resistant modifier, and 65 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0080] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

[0081] Comparative Example 3 (the preparation methods of crosslinking agent A and crosslinking agent B are changed, and the remaining steps are consistent with those of Example 1): preparation of double bond-containing modified nylon;

[0082] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker B;

[0085] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0088] S5: adding a heat stabilizer, 12 parts of a heat-resistant modifier, and 65 parts of double-bond modified nylon to 200 parts of a mixed solvent, stirring evenly, and performing ultrasonic treatment at 25 kHz for 2 h under the conditions of a UV lamp of 250 W and λ=365 nm to remove the solvent, thereby obtaining pretreated nylon particles;

[0089] S6: adding pretreated nylon particles and double-bond modified nylon in a mass ratio of 5:100 into a screw extruder, and performing melt spinning at 290° C. to obtain 950dtex high-performance nylon industrial yarn; twisting the high-performance nylon industrial yarn as warp yarn; using cotton yarn as weft yarn, weaving, dipping, drying, heat-stretching and shaping, and winding to obtain high-performance polyamide cord fabric.

[0090] Comparative Example 4 (no pretreatment, the remaining method steps are consistent with Example 1): S1: preparation of double bond-containing modified nylon;

[0091] S2: Take 6 parts of diethanolamine and 5 parts of formaldehyde, stir at 40°C for 3 hours, heat to 75°C, evacuate under reduced pressure, cool to 60°C, add 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 3 hours to obtain an 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker 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-benzenetricarboxylic acid chloride and 40 parts of acetone, stir at 30°C for 2h, remove the solvent, and obtain crosslinker B;

[0094] 1,3,5-Benzenetricarboxylic acid chloride is 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 the 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 the composite cross-linking agent and 35 parts of acetone dropwise over 1 hour, stir at 30°C for 12 hours, remove the solvent, and obtain a heat-resistant modifier;

[0097] S5: Evenly mix the heat stabilizer, 12 parts of heat-resistant modifier and 65 parts of double-bond modified nylon, add them into a screw extruder, and perform melt spinning at 290°C to obtain 950dtex high-performance nylon industrial yarn; twist the high-performance nylon industrial yarn as warp yarn; use cotton yarn as weft yarn, weave, dip, dry, heat-stretch and shape, and wind up to obtain high-performance polyamide cord fabric.

[0098] In the above examples, the test methods used are conventional methods unless otherwise specified; 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, product number: S46419, Shanghai Yuanye); 4-hydroxy-2,2,6,6-tetramethylpiperidine (CAS: 2403-88-5); triethylamine (CAS: 121-44-8); 1,3,5-benzenetricarboxylic acid chloride (CAS: 4422-95-1); 4-mercapto-1-butanol (CAS: 14970-83-3); m-cresol (CAS: 108-39-4); resorcinol (CAS: 108-46-3); butylpyrrolidone rubber latex (A053489, Zhengzhou Huiju Chemical Co., Ltd.); 25% ammonia water (Shanghai Pande International Trade Co., Ltd.).

[0099] Experiment: Take the high-performance polyamide cord fabrics prepared in Examples 1 to 3 and Comparative Examples 1 to 4; (1) refer to GB / T9101-2002 to test the dry heat shrinkage rate (177°C, 2min); (2) refer to GB / T 9101-2002 to test the heat resistance strength retention rate; see the table below for specific data;

[0100] Dry heat shrinkage / % 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] Conclusion: Comparative Example 1 and Comparative Example 2 changed the addition amount of cross-linking agent C (1,3,5-benzenetricarboxylic acid chloride), and the performance decreased. It can be seen that the degree of branching of the heat-resistant modifier has an important influence on the performance; Comparative Example 3 changed the preparation method of cross-linking agent A and cross-linking agent B, and increased the addition amount of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 4-mercapto-1-butanol, thereby affecting the number of acyl chloride groups in cross-linking agents A and B, and affecting the structure and molecular weight of the heat-resistant modifier, resulting in performance degradation; Comparative Example 4 was not pretreated, and the performance was not as good as that of the embodiment; In summary, the high-performance polyamide cord fabric prepared by the present invention has good 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing high-performance polyamide cord fabric, characterized in that: The following steps are involved: S1: Take diethanolamine and formaldehyde, stir at 40-45°C for 2-3h, heat to 75-80°C, reduce pressure and evacuate, cool to 60-65°C, add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, continue stirring for 2-3h to obtain an intermediate; S2: Take the intermediate, triethylamine and acetone, cool to 3-5°C, add triethylamine under nitrogen protection, stir evenly, drop a mixed solution of the composite cross-linking agent and acetone, stir at 25-30°C for 10-12h, remove the solvent, and obtain a heat-resistant modifier; S3: adding a heat stabilizer, a heat-resistant modifier and nylon particles into a mixed solvent, stirring evenly, ultrasonically treating for 1 to 2 hours under ultraviolet light, removing the solvent, and obtaining pretreated nylon particles; S4: adding the pretreated nylon particles and the nylon particles together into a screw extruder for melt spinning to obtain high-performance nylon industrial yarns; The nylon industrial yarn is twisted as the warp yarn, and the cotton yarn is used as the weft yarn to weave the cloth; the high-performance polyamide cord fabric is obtained by dipping, drying, heat stretching and shaping, and winding; In step S4, the mass ratio of the pretreated nylon particles to the nylon particles is (1-5)-(100:1000).

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

3. The method for preparing a high-performance polyamide cord fabric according to claim 1, characterized in that: The composite cross-linking agent includes cross-linking agent A, cross-linking agent B, and cross-linking agent C; The preparation of the cross-linking agent A comprises the following steps: taking 4-hydroxy-2,2,6,6-tetramethylpiperidine, triethylamine and acetone, cooling to 3-5°C, adding triethylamine and stirring evenly under nitrogen protection, adding 1,3,5-benzenetricarboxylic acid chloride and acetone, stirring at 25-30°C for 2-3h, and removing the solvent to obtain the cross-linking agent A; The preparation of the cross-linking agent B comprises the following steps: Take 4-mercapto-1-butanol, triethylamine and acetone, cool to 3-5°C, add triethylamine and stir evenly under nitrogen protection, add 1,3,5-benzenetricarboxylic acid chloride and acetone, stir at 25-30°C for 2-3h, remove the solvent, and obtain crosslinker B; The cross-linking agent C is 1,3,5-benzenetricarboxylic acid chloride.

4. The method for preparing the high performance polyamide cord fabric according to claim 3, characterized in that: In the composite crosslinking agent, the mass ratio of crosslinking agent A, crosslinking agent B and crosslinking agent C is (3-5): (4-6): (1-2).

5. The method for preparing the high performance polyamide cord fabric according to claim 3, characterized in that: The cross-linking agent A comprises the following raw materials, calculated by weight: 5.5 to 6.5 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine and 9 to 10 parts of 1,3,5-benzenetricarboxylic acid chloride; the cross-linking agent B comprises the following raw materials, calculated by weight: 3.5 to 4.2 parts of 4-mercapto-1-butanol and 9 to 10 parts of 1,3,5-benzenetricarboxylic acid chloride.

6. The method for preparing high-performance polyamide cord fabric according to claim 1, characterized in that: The nylon particles include one or more of nylon 66, nylon 6, and nylon 56.

7. The method for preparing high-performance polyamide cord fabric according to claim 1, characterized in that: The nylon particles are modified before being added to obtain double bond-containing modified nylon, which is then introduced; the preparation of the double bond-containing modified nylon includes the following steps: Step 1: Take nylon particles, add them into a mixed solution of formaldehyde and NaOH, stir at 80-90°C 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°C for 1-2h, wash and dry to obtain double bond modified nylon; The N-hydroxymethyl modified nylon comprises the following raw materials, calculated by weight: 10 parts of nylon particles, 60-70 parts of a mixed solution of formaldehyde and NaOH; in the mixed solution of formaldehyde and NaOH, the concentration of formaldehyde is 10-15wt%, and the content of NaOH is 0.3-0.7wt%; The double bond-containing modified nylon comprises the following raw materials, calculated by weight: 10 parts of N-hydroxymethyl modified nylon, 80-100 parts of methacrylic acid solution; in the methacrylic acid solution, the methacrylic acid content is 30-40wt%, and the rest is water.

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

9. High-performance polyamide cord fabric prepared according to the method for preparing high-performance polyamide cord fabric according to any one of claims 1 to 8.

10. Use of the high-performance polyamide cord fabric according to claim 9 in a skeleton material of a rubber product.