High tensile strength polyester tire cord fabric and method of making same

Abstract

The application belongs to the field of polyester base cloth materials, and provides a high tensile strength polyester base cloth and a preparation method thereof, and constructs a modified polyester which can maintain excellent mechanical properties under high stress conditions. First, polyethylene glycol monomethyl ether is used to react with maleic anhydride to introduce flexible polyether chain segments and unsaturated double bond structures, and then free radical grafting of acrylic acid and ring-opening reaction of epichlorohydrin are used to introduce functional groups, so that the flexible chain segments have reactivity with polyester chains and other components, thereby enhancing the intermolecular compatibility and binding force in subsequent polymerization. In the preparation process of the polyester matrix, modified liquid crystal polyester and modified poly-p-phenylene benzobisoxazole are added to improve the tensile strength of the material through the rigid molecular chain structure thereof, and meanwhile, the flexible chain segments of the modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether glycol effectively disperse internal stress, further improving the overall mechanical properties and structural stability of the material.

Description

Technical Field

[0001] This invention belongs to the field of polyester tire base fabric materials, and relates to a high tensile strength polyester tire base fabric and its preparation method. Background Technology

[0002] Polyester tire base fabric is an important industrial material widely used in tires, conveyor belts, composite materials, and other high-performance products. In recent years, with the rapid development of the automotive industry and high-performance materials, the performance requirements for polyester tire base fabric have been continuously increasing, especially in terms of tensile strength. Patent CN115418798A discloses a production process for high-strength polyester filament tire base fabric. It produces semi-finished high-strength polyester filament tire base fabric through polyester spunbonding and needle-punching reinforcement, followed by impregnation and shaping processes to finally obtain the high-strength polyester filament tire base fabric product. This patent uses polyester chips as raw materials for direct production, but the mechanical strength of the resulting product is relatively limited. Traditional polyester tire base fabric is mainly made of polyethylene terephthalate (PET). Although PET has good strength and toughness, its tensile strength is still somewhat insufficient under high load conditions. Therefore, it is necessary to develop a high-tensile-strength polyester tire base fabric to meet actual production needs. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a high tensile strength polyester base fabric and its preparation method. Through esterification with maleic anhydride, free radical grafting of acrylic acid, and chemical reaction with epichlorohydrin, flexible segments and functional groups are introduced. Modified liquid crystal polyester and modified poly(p-phenylenebenzobisoxazole) are embedded into the polyester matrix, imparting good tensile strength and intermolecular bonding to the material. The synergistic effect of flexible polyether chains and rigid aromatic segments achieves a balance between rigidity and flexibility, thereby improving toughness and preventing brittle fracture, thus meeting the needs of actual production.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a method for preparing a high tensile strength polyester base fabric, wherein the preparation method comprises:

[0006] Step S1: Mix 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid, add 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, heat to a first temperature under nitrogen protection to react fully, cool to room temperature after the reaction is complete, and vacuum dry at a second temperature to obtain modified liquid crystal polyester;

[0007] Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain a poly(p-phenylenebenzobisoxazole) solution. Add polyetheramine and silane coupling agent KH-550, stir at the first stirring speed, and then vacuum dry at the second temperature to obtain modified poly(p-phenylenebenzobisoxazole).

[0008] Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether is heated to a third temperature, maleic anhydride, p-toluenesulfonic acid and hydroquinone are added, the temperature is raised to a fourth temperature to fully react, the temperature is adjusted to a fifth temperature, acrylic acid and benzoyl peroxide are added to continue the reaction, the temperature is further adjusted to a sixth temperature, epichlorohydrin and tetrabutylammonium bromide are added to continue the reaction, and modified polyethylene glycol monomethyl ether is obtained.

[0009] Step S4: Add the dicarboxylic acid mixture to the diol mixture, then add the modified liquid crystal polyester and the modified poly(p-phenylenebenzobisoxazole). Under nitrogen protection, heat to the seventh temperature and stir the reaction at the second stirring speed. Adjust the temperature to the eighth temperature, add the modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether diol and stir evenly. Then add antimony acetate, tetrapropyl zirconate and triethyl phosphate and react fully. After the reaction is complete, adjust the temperature to the seventh temperature, and add trimethylolpropane triacrylate, triisocyanate, hindered phenolic antioxidant and phosphite in sequence. After stirring evenly, extrude to obtain the modified polyester.

[0010] Step S5: The modified polyester is vacuum dried at a sixth temperature, and then the dried modified polyester is heated to a first temperature. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with glue, dried and then finished to obtain a high tensile strength polyester base fabric.

[0011] The copolymerization of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid forms a polyester structure with liquid crystal properties. Liquid crystal polyesters exhibit high molecular order, providing stronger molecular chain orientation and crystallinity, thereby improving the mechanical properties of the fiber. Specifically, naphthalenedicarboxylic acid, being an aromatic structure, increases the rigidity of the polyester chain, resulting in superior mechanical strength. The naphthalene ring is a polycyclic aromatic structure composed of two conjugated benzene rings, exhibiting high planarity and rigidity. The arrangement of the carboxyl groups at the 2,6-positions ensures that the ester bonds formed after esterification are collinear with the naphthalene ring plane, resulting in a linear molecular chain. The π-π conjugation of the naphthalene ring restricts the free rotation of the molecule, contributing to the linearity of the chain segments. The benzene ring, a typical aromatic ring, possesses high symmetry and planarity. The para-hydroxyl and carboxyl groups in p-hydroxybenzoic acid are linearly arranged on the benzene ring; this symmetry ensures that the molecular chain formed after esterification remains highly linear. 4,4'-Dihydroxybiphenyl consists of two benzene rings linearly linked by single bonds (biphenyl structure). In the static state, the two benzene rings tend to be coplanar. This coplanarity further enhances the linearity and rigidity of the molecular chain. Through esterification, the two hydroxyl groups of 4,4'-dihydroxybiphenyl can attach to different molecular chains, acting as "bridges" and further enhancing the regularity of the molecular chain. In liquid crystal polyester molecules, the aromatic rings of 2,6-naphthalenedicarboxylic acid, p-hydroxybenzoic acid, and 4,4'-dihydroxybiphenyl are connected by ester bonds. Ester bonds have a certain conjugation effect, restricting the orientation between the ester bond and the aromatic ring to some extent, tending to maintain collinearity with the aromatic ring. This restriction keeps the molecular chain highly linear, ultimately forming a highly linearized main chain.

[0012] Polyetheramines are polymers obtained by reacting epoxy compounds with amine groups, containing multiple amine and ether structures. Poly(p-phenylenebenzobisoxazole) is a polymer with high rigidity and high temperature resistance. Its molecule contains p-phenylene (benzene ring) and bisoxazole ring. The bisoxazole ring is an aromatic heterocyclic compound containing a nitrogen atom. In the molecular structure of poly(p-phenylenebenzobisoxazole), there are unreacted carbonyl groups. These carbonyl groups have strong nucleophilicity and can react with amine groups to form an amide bond, which firmly anchors the flexible polyether segments to the poly(p-phenylenebenzobisoxazole) molecular chain. The presence of flexible regions alleviates the excessive rigidity of the molecular chain, allowing the material to distribute internal stress more evenly under external force, improving the fracture toughness of the material, and reducing material failure caused by local chain segment breakage. In the bisoxazole ring of poly(p-phenylenebenzobisoxazole), the lone pair electrons on the nitrogen atom and the hydrogen atoms of the amine group can form hydrogen bonds, enhancing the overall strength between molecular chains. The amino groups in the silane coupling agent KH-550 can chemically bond with the active sites on the surface of the poly(p-phenylenebenzobisoxazole) molecular chain. The siloxane portion of KH-550 can form covalent or hydrogen bonds with other components, further improving interfacial bonding and optimizing the overall strength of the composite material.

[0013] Polyethylene glycol monomethyl ether (PEG) is a common flexible segmental material with hydroxyl groups at its ends. Maleic anhydride is a compound with acyl anhydride groups. The anhydride group is a highly electrophilic chemical functional group that readily reacts with nucleophilic substances (such as hydroxyl groups) to undergo ring-opening reactions. The hydroxyl groups at the ends of PEG and maleic anhydride undergo esterification, with the hydroxyl groups at the ends of PEG being esterified into ester groups. Simultaneously, the two acyl groups of maleic anhydride are attached to the ends of the PEG segment, introducing ester groups and double bonds of maleic anhydride. Benzoyl peroxide decomposes into two benzoyl free radicals under heating conditions. These free radicals initiate a radical addition reaction between acrylic acid and the double bond in the esterification product of polyethylene glycol monomethyl ether, grafting acrylic acid onto the polyether chain to form a carboxyl-containing side chain structure. The grafted carboxyl groups can form hydrogen bonds or covalent bonds with other components (such as epichlorohydrin and modified liquid crystal polyester), thereby enhancing the intermolecular forces and tensile strength. Epichlorohydrin undergoes a ring-opening addition reaction with the remaining hydroxyl groups on the polyethylene glycol monomethyl ether molecular chain, forming ether bonds and introducing epoxy groups. These epoxy groups can further undergo addition reactions with other functional groups (carboxyl and amino groups) in subsequent reactions, forming a network cross-linked structure and improving the overall mechanical properties of the material.

[0014] The reaction of dicarboxylic acid mixtures with glycol mixtures generates polyester chains through polycondensation. Modified liquid crystal polyester and modified poly(p-phenylenebenzobisoxazole) are introduced into the reaction system; these substances all enhance the ordered arrangement of polymer chains. Modified liquid crystal polyester, by providing higher molecular order, helps polyester fibers form a better orientation structure during spinning, improving mechanical properties. Modified poly(p-phenylenebenzobisoxazole) has high strength; its introduction can improve the rigidity and tensile strength of the polyester. The terminal hydroxyl groups in modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether diol undergo esterification with the carboxyl groups of the polyester molecular chain, embedding themselves into the polyester chain. The flexible segments in modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether diol can disperse internal stress in the material, improving its toughness.

[0015] As a preferred technical solution of the present invention, in step S1, the mass ratio of 2,6-naphthalenedicarboxylic acid to p-hydroxybenzoic acid is 1:(1.5-2), for example, it can be 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] In some alternative instances, the mass of the 4,4'-dihydroxybiphenyl is 8-12% of the total mass of 2,6-naphthoic acid and p-hydroxybenzoic acid, for example, it can be 8.0%, 8.4%, 8.8%, 9.2%, 9.6%, 10.0%, 10.4%, 10.8%, 11.2%, 11.6% or 12.0%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0017] In some alternative instances, the mass of the acetoxybenzoic acid is 4-6% of the total mass of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid, for example, it may be 4.0%, 4.2%, 4.4%, 4.6%, 4.8%, 5.0%, 5.2%, 5.4%, 5.6%, 5.8% or 6.0%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0018] In some alternative instances, the first temperature is 285-295°C, for example, it can be 285.0°C, 286.0°C, 287.0°C, 288.0°C, 289.0°C, 290.0°C, 291.0°C, 292.0°C, 293.0°C, 294.0°C or 295.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0019] In some alternative instances, the reaction time at the first temperature is 1.5-2.5 h, for example, it can be 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, 2.0 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h or 2.5 h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] In some alternative instances, the second temperature is 115-125°C, for example, it can be 115.0°C, 116.0°C, 117.0°C, 118.0°C, 119.0°C, 120.0°C, 121.0°C, 122.0°C, 123.0°C, 124.0°C or 125.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some optional instances, the vacuum drying time is 7-9 hours, for example, 7.0 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours, 8.0 hours, 8.2 hours, 8.4 hours, 8.6 hours, 8.8 hours, or 9.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0022] As a preferred technical solution of the present invention, in step S2, the mass fraction of the poly(p-phenylenebenzobisoxazole) solution is 8-12 wt.%, for example, it can be 8.0 wt.%, 8.4 wt.%, 8.8 wt.%, 9.2 wt.%, 9.6 wt.%, 10.0 wt.%, 10.4 wt.%, 10.8 wt.%, 11.2 wt.%, 11.6 wt.%, or 12.0 wt.%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] In some alternative instances, the polyetheramine is 4-6% of poly(p-phenylenebenzobisoxazole), for example, 4.0%, 4.2%, 4.4%, 4.6%, 4.8%, 5.0%, 5.2%, 5.4%, 5.6%, 5.8%, or 6.0%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0024] In some alternative instances, the mass of the silane coupling agent KH-550 is 1.5-2.5% of poly(p-phenylenebenzobisoxazole), for example, it can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4% or 2.5%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0025] In some alternative instances, the first stirring speed is 200-300 rpm, for example, 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm or 300 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0026] In some optional instances, the stirring time is 1-2 hours, for example, it can be 1.0 hours, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0027] In some optional instances, the vacuum drying time is 7-9 hours, for example, 7.0 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours, 8.0 hours, 8.2 hours, 8.4 hours, 8.6 hours, 8.8 hours, or 9.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0028] As a preferred technical solution of the present invention, in step S3, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is (1.2-1.7):1, for example, it can be 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1 or 1.7:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] In some alternative instances, the mass of the p-toluenesulfonic acid is 0.1-0.2% of the mass of polyethylene glycol monomethyl ether, for example, it may be 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, or 0.2%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0030] In some alternative instances, the hydroquinone is 0.05-0.1% of the mass of polyethylene glycol monomethyl ether, for example, it may be 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0031] In some alternative instances, the fourth temperature is 165-175°C, for example, it can be 165.0°C, 166.0°C, 167.0°C, 168.0°C, 169.0°C, 170.0°C, 171.0°C, 172.0°C, 173.0°C, 174.0°C or 175.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] In some alternative instances, the reaction time at the fourth temperature is 2.5-3.0 h, for example, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3.0 h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0033] In some alternative instances, the fifth temperature is 140-150°C, for example, it can be 140.0°C, 141.0°C, 142.0°C, 143.0°C, 144.0°C, 145.0°C, 146.0°C, 147.0°C, 148.0°C, 149.0°C or 150.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0034] In some alternative instances, the mass of the acrylic acid is 9-11% of the mass of polyethylene glycol monomethyl ether, for example, it can be 9.0%, 9.2%, 9.4%, 9.6%, 9.8%, 10.0%, 10.2%, 10.4%, 10.6%, 10.8%, or 11.0%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0035] In some alternative instances, the mass of benzoyl peroxide is 0.3-0.5% of the mass of acrylic acid, for example, it may be 0.30%, 0.32%, 0.34%, 0.36%, 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48%, or 0.50%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0036] In some alternative instances, the reaction time at the fifth temperature is 1.5-2.0 h, for example, it can be 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2.0 h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0037] In some alternative instances, the sixth temperature is 110-120°C, for example, it can be 110.0°C, 111.0°C, 112.0°C, 113.0°C, 114.0°C, 115.0°C, 116.0°C, 117.0°C, 118.0°C, 119.0°C or 120.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0038] In some alternative instances, the mass of epichlorohydrin is 2.5-3.5% of the mass of polyethylene glycol monomethyl ether, for example, it can be 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4% or 3.5%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0039] In some alternative instances, the mass of the tetrabutylammonium bromide is 1.0-1.2% of the mass of epichlorohydrin, for example, it may be 1.0%, 1.02%, 1.04%, 1.06%, 1.08%, 1.1%, 1.12%, 1.14%, 1.16%, 1.18%, or 1.2%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0040] In some optional instances, the reaction time at the sixth temperature is 4-5 hours, for example, 4.0 hours, 4.1 hours, 4.2 hours, 4.3 hours, 4.4 hours, 4.5 hours, 4.6 hours, 4.7 hours, 4.8 hours, 4.9 hours, or 5.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0041] As a preferred technical solution of the present invention, in step S4, the dicarboxylic acid mixture consists of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid, with a mass ratio of 18:1:1.

[0042] In some optional examples, the diol mixture is ethylene glycol, 1,4-cyclohexanediol, and neopentyl glycol in a mass ratio of 15:2:1.

[0043] In some optional instances, the mass ratio of the diformate mixture to the diol mixture is 1:2.

[0044] In some alternative examples, the mass of the modified liquid crystal polyester is 1.8-2.2% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it can be 1.8%, 1.84%, 1.88%, 1.92%, 1.96%, 2.0%, 2.04%, 2.08%, 2.12%, 2.16%, or 2.2%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0045] In some alternative instances, the mass of the modified poly(p-phenylenebenzobisoxazole) is 0.8-1.2% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.8%, 0.84%, 0.88%, 0.92%, 0.96%, 1.0%, 1.04%, 1.08%, 1.12%, 1.16%, or 1.2%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0046] In some alternative instances, the seventh temperature is 230-240°C, for example, it can be 230.0°C, 231.0°C, 232.0°C, 233.0°C, 234.0°C, 235.0°C, 236.0°C, 237.0°C, 238.0°C, 239.0°C or 240.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0047] In some optional instances, the second stirring speed is 100-200 rpm, for example, it can be 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm or 200 rpm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0048] In some alternative instances, the reaction time for the second stirring rate is 3-4 h, for example, it can be 3.0 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h, 3.5 h, 3.6 h, 3.7 h, 3.8 h, 3.9 h or 4.0 h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0049] In some alternative instances, the eighth temperature is 270-280°C, for example, it can be 270.0°C, 271.0°C, 272.0°C, 273.0°C, 274.0°C, 275.0°C, 276.0°C, 277.0°C, 278.0°C, 279.0°C or 280.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0050] In some optional instances, the mass of the modified polyethylene glycol monomethyl ether is 1.3-1.7% of the total mass of the dicarboxylic acid mixture and the glycol mixture, for example, it can be 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0051] In some optional instances, the mass of the polytetrahydrofuran ether diol is 1.3-1.7% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it can be 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0052] In some alternative instances, the mass of the antimony acetate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.02%, 0.025%, 0.03%, 0.035% or 0.04%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] In some alternative instances, the mass of the tetrapropyl zirconate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.02%, 0.025%, 0.03%, 0.035% or 0.04%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0054] In some alternative instances, the mass of the triethyl phosphate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.02%, 0.025%, 0.03%, 0.035% or 0.04%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0055] In some alternative instances, the reaction time for adding triethyl phosphate is 4-5 h, for example, 4.0 h, 4.1 h, 4.2 h, 4.3 h, 4.4 h, 4.5 h, 4.6 h, 4.7 h, 4.8 h, 4.9 h, or 5.0 h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0056] In some alternative instances, the mass of the trimethylolpropane triacrylate is 0.4-0.6% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.4%, 0.42%, 0.44%, 0.46%, 0.48%, 0.5%, 0.52%, 0.54%, 0.56%, 0.58%, or 0.6%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0057] In some alternative instances, the mass of the triisocyanate is 0.2-0.4% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.32%, 0.34%, 0.36%, 0.38%, or 0.4%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0058] In some optional instances, the hindered phenolic antioxidant is 0.15-0.25% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, or 0.25%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The hindered phenolic antioxidant is antioxidant 1010.

[0059] In some alternative instances, the mass of the phosphite is 0.6-0.8% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it may be 0.6%, 0.62%, 0.64%, 0.66%, 0.68%, 0.70%, 0.72%, 0.74%, 0.76%, 0.78%, or 0.8%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0060] As a preferred technical solution of the present invention, in step S5, the sixth temperature is 110-120℃, for example, it can be 110.0℃, 111.0℃, 112.0℃, 113.0℃, 114.0℃, 115.0℃, 116.0℃, 117.0℃, 118.0℃, 119.0℃ or 120.0℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] In some optional instances, the vacuum drying time is 8-10 h, for example, it can be 8.0 h, 8.2 h, 8.4 h, 8.6 h, 8.8 h, 9.0 h, 9.2 h, 9.4 h, 9.6 h, 9.8 h or 10.0 h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0062] Secondly, the present invention provides a high tensile strength polyester base fabric obtained by the preparation method described in the first aspect.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By introducing the copolymerization reaction of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid, a polyester structure with liquid crystal properties is formed. The liquid crystal polyester has a high degree of molecular arrangement order. This highly ordered arrangement of molecular chains can enhance the interaction between molecules, reduce molecular chain slippage, maintain higher mechanical stability during stretching, and improve tensile strength; (2) The introduction of flexible segments (flexible polyether segments generated by the reaction of polyethylene glycol monomethyl ether and maleic anhydride) improves the flexibility of the fiber. These flexible segments provide adjustable elasticity for polyester molecules, enabling the fiber to undergo a certain degree of deformation under stretching and impact, reducing the occurrence of brittle fracture, and the fiber has better extensibility and impact resistance under load; (3) Acrylic acid is grafted onto the polyether chain to form a structure with carboxyl side chains. Carboxyl groups can form hydrogen bonds or covalent bonds, thereby greatly enhancing the interaction force between molecular chains and further improving the mechanical properties of the fiber. Attached Figure Description

[0064] Figure 1 The flowchart shows a method for preparing a high tensile strength polyester base fabric provided in Embodiments 1-4 of the present invention.

[0065] Figure 2 This is a SEM image of the high tensile strength polyester base fabric prepared in Embodiment 1 of the present invention;

[0066] Figure 3 This is a TEM image of the high tensile strength polyester base fabric prepared in Embodiment 1 of the present invention. Detailed Implementation

[0067] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0068] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products.

[0069] Example 1

[0070] This embodiment provides a method for preparing a high tensile strength polyester base fabric, such as... Figure 1 As shown, the preparation method specifically includes the following steps:

[0071] Step S1: 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid are mixed in a mass ratio of 1:1.7. 8.5% of 4,4'-dihydroxybiphenyl and 4.8% of acetoxybenzoic acid relative to the total mass of the two acids are added. Under nitrogen protection, the mixture is heated to 288°C and reacted for 1.9 h. After the reaction is completed, it is cooled to room temperature and dried under vacuum at 117°C for 7.9 h to obtain the modified liquid crystal polyester.

[0072] Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain a 9.6 wt.% poly(p-phenylenebenzobisoxazole) solution. Add 4.6% polyetheramine (relative to the mass of poly(p-phenylenebenzobisoxazole)) and 1.7% silane coupling agent KH-550 (relative to the mass of poly(p-phenylenebenzobisoxazole)). Stir at 220 rpm for 1.4 h and then vacuum dry at 118 °C for 7.4 h to obtain modified poly(p-phenylenebenzobisoxazole).

[0073] Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether (PEG) is heated to 129°C, and maleic anhydride is added. The mass ratio of PEG to maleic anhydride is 1.4:1. 0.14% (by weight of PEG) of p-toluenesulfonic acid and 0.06% (by weight of PEG) of hydroquinone are added. The temperature is raised to 168°C and the reaction is allowed to proceed for 2.7 hours. The temperature is then adjusted to 145°C, and 9.7% (by weight of PEG) of acrylic acid and 0.38% (by weight of PEG) of benzoyl peroxide are added. The reaction continues for 1.6 hours. The temperature is further adjusted to 114°C, and 2.9% (by weight of PEG) of epichlorohydrin and 1.08% (by weight of epichlorohydrin) of tetrabutylammonium bromide are added. The reaction continues for 4.6 hours to obtain modified PEG.

[0074] Step S4: A mixture of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid in a mass ratio of 18:1:1 is added to a mixture of ethylene glycol, 1,4-cyclohexanediethanol, and neopentyl glycol in a mass ratio of 15:2:1, with the mass ratio of the terephthalic acid mixture to the glycol mixture being 1:2. Then, 1.9% of modified liquid crystal polyester and 0.88% of modified poly(p-phenylenebenzobisoxazole) relative to the total mass of the terephthalic acid and glycol mixtures are added. Under nitrogen protection, the temperature is raised to 234°C, and the mixture is stirred at 140 rpm for 3.3 hours. The temperature is then adjusted to 273°C, and the mixture of the terephthalic acid mixture and the glycol mixture is added... 1.46% of modified polyethylene glycol monomethyl ether (by total mass of alcohol mixture) and 1.37% of polytetrahydrofuran ether diol (by total mass of dicarboxylic acid mixture and diol mixture) were stirred evenly. Then, 0.02% of antimony acetate, 0.03% of tetrapropyl zirconate, and 0.03% of triethyl phosphate (by total mass of dicarboxylic acid mixture and diol mixture) were added and reacted thoroughly for 4.3 hours. After the reaction was completed, the temperature was adjusted to 235°C, and 0.47% of trimethylolpropane triacrylate, 0.29% of triisocyanate, 0.18% of antioxidant 1010, and 0.65% of phosphite (by total mass of dicarboxylic acid mixture and diol mixture) were added sequentially. After stirring evenly, the mixture was extruded to obtain modified polyester.

[0075] In step S5, the modified polyester is vacuum dried at 115°C for 8.6 hours, and then the dried modified polyester is heated to 288°C. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with resin, dried and then finished to obtain a high tensile strength polyester base fabric.

[0076] Figure 2 The SEM image of the high tensile strength polyester base fabric prepared in this embodiment shows that the fiber distribution is relatively uniform, and there is no significant aggregation or coarseness between the fibers. Figure 3 This is a TEM image of the high tensile strength polyester base fabric prepared in this embodiment.

[0077] Example 2

[0078] This embodiment provides a method for preparing a high tensile strength polyester base fabric, such as... Figure 1 As shown, the preparation method specifically includes the following steps:

[0079] Step S1: 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid are mixed in a mass ratio of 1:1.6. 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, with a relative mass of 8.7% of the total mass of the two acids and a relative mass of 4.2% of the total mass of the two acids, are added. Under nitrogen protection, the mixture is heated to 289°C and reacted completely for 1.8 h. After the reaction is completed, the mixture is cooled to room temperature and dried under vacuum at 119°C for 8.4 h to obtain the modified liquid crystal polyester.

[0080] Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain an 11.2 wt.% poly(p-phenylenebenzobisoxazole) solution. Add 5.2% polyetheramine (relative to the mass of poly(p-phenylenebenzobisoxazole)) and 2.1% silane coupling agent KH-550 (relative to the mass of poly(p-phenylenebenzobisoxazole)). Stir at 240 rpm for 1.3 h, and then vacuum dry at 117 °C for 7.5 h to obtain modified poly(p-phenylenebenzobisoxazole).

[0081] Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether (PEG) is heated to 127°C, and maleic anhydride is added. The mass ratio of PEG to maleic anhydride is 1.3:1. 0.18% p-toluenesulfonic acid and 0.05% hydroquinone (relative to the mass of PEG) are added. The temperature is raised to 172°C and reacted completely for 2.5 hours. The temperature is then adjusted to 148°C, and 10.3% acrylic acid and 0.46% benzoyl peroxide (relative to the mass of PEG) are added. The reaction continues for 1.5 hours. The temperature is further adjusted to 118°C, and 3.3% epichlorohydrin and 1.04% tetrabutylammonium bromide (relative to the mass of epichlorohydrin) are added. The reaction continues for 4.3 hours to obtain modified PEG.

[0082] Step S4: A mixture of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid in a mass ratio of 18:1:1 is added to a mixture of ethylene glycol, 1,4-cyclohexanediethanol, and neopentyl glycol in a mass ratio of 15:2:1, with the mass ratio of the terephthalic acid mixture to the glycol mixture being 1:2. Then, 2.2% of the modified liquid crystal polyester and 0.96% of the modified poly(p-phenylenebenzobisoxazole) relative to the total mass of the terephthalic acid and glycol mixtures are added. Under nitrogen protection, the temperature is raised to 238°C, and the mixture is stirred at 180 rpm for 3.8 hours. The temperature is then adjusted to 277°C, and the mixture of the terephthalic acid mixture and the glycol mixture is added... 1.53% of modified polyethylene glycol monomethyl ether (by total mass of alcohol mixture) and 1.46% of polytetrahydrofuran ether diol (by total mass of dicarboxylic acid mixture and diol mixture) were mixed evenly. Then, 0.03% of antimony acetate, 0.02% of tetrapropyl zirconate, and 0.02% of triethyl phosphate (by total mass of dicarboxylic acid mixture and diol mixture) were added and reacted thoroughly for 4.2 hours. After the reaction was completed, the temperature was adjusted to 238°C, and 0.51% of trimethylolpropane triacrylate, 0.37% of triisocyanate, 0.19% of antioxidant 1010, and 0.74% of phosphite (by total mass of dicarboxylic acid mixture and diol mixture) were added sequentially. After stirring evenly, the mixture was extruded to obtain modified polyester.

[0083] In step S5, the modified polyester is vacuum dried at 119°C for 9.9 hours, and then the dried modified polyester is heated to 295°C. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with resin, dried and then finished to obtain a high tensile strength polyester base fabric.

[0084] Example 3

[0085] This embodiment provides a method for preparing a high tensile strength polyester base fabric, such as... Figure 1 As shown, the preparation method specifically includes the following steps:

[0086] Step S1: 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid are mixed in a mass ratio of 1:1.9. 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, with a relative mass of 10.3% of the total mass of the two acids and a relative mass of 4.6% of the total mass of the two acids, are added. Under nitrogen protection, the mixture is heated to 294°C and reacted completely for 1.6 h. After the reaction is completed, the mixture is cooled to room temperature and dried under vacuum at 124°C for 8.1 h to obtain the modified liquid crystal polyester.

[0087] Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain a 10.4 wt.% poly(p-phenylenebenzobisoxazole) solution. Add 5.6% polyetheramine (relative to the mass of poly(p-phenylenebenzobisoxazole)) and 2.3% silane coupling agent KH-550 (relative to the mass of poly(p-phenylenebenzobisoxazole)). Stir at 280 rpm for 1.7 h and then vacuum dry at 123 °C for 8.2 h to obtain modified poly(p-phenylenebenzobisoxazole).

[0088] Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether (PEG) is heated to 132°C, and maleic anhydride is added. The mass ratio of PEG to maleic anhydride is 1.6:1. 0.12% (by weight of PEG) of p-toluenesulfonic acid and 0.09% (by weight of PEG) of hydroquinone are added. The temperature is raised to 175°C and the reaction is allowed to proceed for 3.0 h. The temperature is then adjusted to 142°C, and 10.7% (by weight of PEG) of acrylic acid and 0.41% (by weight of PEG) of benzoyl peroxide are added. The reaction continues for 1.9 h. The temperature is then adjusted to 116°C, and 3.1% (by weight of PEG) of epichlorohydrin and 1.12% (by weight of epichlorohydrin) of tetrabutylammonium bromide are added. The reaction continues for 4.9 h to obtain modified PEG.

[0089] Step S4: A mixture of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid in a mass ratio of 18:1:1 is added to a mixture of ethylene glycol, 1,4-cyclohexanediethanol, and neopentyl glycol in a mass ratio of 15:2:1, with the mass ratio of the terephthalic acid mixture to the glycol mixture being 1:2. Then, 2.1% of the modified liquid crystal polyester and 1.13% of the modified poly(p-phenylenebenzobisoxazole) relative to the total mass of the terephthalic acid and glycol mixtures are added. Under nitrogen protection, the temperature is raised to 231°C, and the mixture is stirred at 190 rpm for 3.5 hours. The temperature is then adjusted to 275°C, and the mixture of the terephthalic acid mixture and the glycol mixture is added... 1.66% of modified polyethylene glycol monomethyl ether (by total mass of alcohol mixture) and 1.54% of polytetrahydrofuran ether diol (by total mass of dicarboxylic acid mixture and diol mixture) were mixed evenly. Then, 0.04% of antimony acetate, 0.04% of tetrapropyl zirconate, and 0.04% of triethyl phosphate (by total mass of dicarboxylic acid mixture and diol mixture) were added and reacted thoroughly for 4.9 hours. After the reaction was completed, the temperature was adjusted to 236°C. Then, 0.59% of trimethylolpropane triacrylate, 0.31% of triisocyanate, 0.23% of antioxidant 1010, and 0.73% of phosphite (by total mass of dicarboxylic acid mixture and diol mixture) were added sequentially. After stirring evenly, the mixture was extruded to obtain modified polyester.

[0090] In step S5, the modified polyester is vacuum dried at 120°C for 9.2 hours, and then the dried modified polyester is heated to 291°C. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with resin, dried and then finished to obtain a high tensile strength polyester base fabric.

[0091] Example 4

[0092] This embodiment provides a method for preparing a high tensile strength polyester base fabric, such as... Figure 1 As shown, the preparation method specifically includes the following steps:

[0093] Step S1: 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid are mixed in a mass ratio of 1:2. 11.4% of 4,4'-dihydroxybiphenyl and 5.3% of acetoxybenzoic acid relative to the total mass of the two acids are added. Under nitrogen protection, the mixture is heated to 292°C and reacted completely for 2.1 h. After the reaction is completed, it is cooled to room temperature and dried under vacuum at 120°C for 8.5 h to obtain the modified liquid crystal polyester.

[0094] Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain an 8.6 wt.% poly(p-phenylenebenzobisoxazole) solution. Add 4.9% polyetheramine (relative to the mass of poly(p-phenylenebenzobisoxazole)) and 1.7% silane coupling agent KH-550 (relative to the mass of poly(p-phenylenebenzobisoxazole)). Stir at 270 rpm for 1.9 h and then vacuum dry at 121 °C for 7.8 h to obtain modified poly(p-phenylenebenzobisoxazole).

[0095] Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether (PEG) is heated to 130°C, and maleic anhydride is added. The mass ratio of PEG to maleic anhydride is 1.5:1. 0.13% p-toluenesulfonic acid and 0.06% hydroquinone (relative to the mass of PEG) are added. The temperature is raised to 166°C and reacted completely for 2.9 hours. The temperature is then adjusted to 150°C, and 9.8% acrylic acid and 0.39% benzoyl peroxide (relative to the mass of PEG) are added. The reaction continues for 1.8 hours. The temperature is further adjusted to 119°C, and 2.6% epichlorohydrin and 1.03% tetrabutylammonium bromide (relative to the mass of epichlorohydrin) are added. The reaction continues for 4.1 hours to obtain modified PEG.

[0096] Step S4: A mixture of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid in a mass ratio of 18:1:1 is added to a mixture of ethylene glycol, 1,4-cyclohexanediethanol, and neopentyl glycol in a mass ratio of 15:2:1, with the mass ratio of the terephthalic acid mixture to the glycol mixture being 1:2. Then, 2.0% of the modified liquid crystal polyester and 0.91% of the modified poly(p-phenylenebenzobisoxazole) relative to the total mass of the terephthalic acid and glycol mixtures are added. Under nitrogen protection, the temperature is raised to 232°C, and the mixture is stirred at 120 rpm for 3.9 hours. The temperature is then adjusted to 279°C, and the mixture of the terephthalic acid mixture and the glycol mixture is added... 1.7% of modified polyethylene glycol monomethyl ether (by total mass of alcohol mixture) and 1.63% of polytetrahydrofuran ether diol (by total mass of dicarboxylic acid mixture and diol mixture) were stirred evenly. Then, 0.03% of antimony acetate, 0.02% of tetrapropyl zirconate, and 0.02% of triethyl phosphate (by total mass of dicarboxylic acid mixture and diol mixture) were added and reacted thoroughly for 4.5 hours. After the reaction was completed, the temperature was adjusted to 234℃, and 0.57% of trimethylolpropane triacrylate, 0.29% of triisocyanate, 0.24% of antioxidant 1010, and 0.62% of phosphite (by total mass of dicarboxylic acid mixture and diol mixture) were added sequentially. After stirring evenly, the mixture was extruded to obtain modified polyester.

[0097] In step S5, the modified polyester is vacuum dried at 113°C for 8.7 hours, and then the dried modified polyester is heated to 286°C. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with resin, dried and then finished to obtain a high tensile strength polyester base fabric.

[0098] Comparative Example 1

[0099] This comparative example provides a method for preparing a high tensile strength polyester base fabric. The difference from Example 1 is that in step S1, the mass ratio of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid is adjusted to 1:2.7. Compared with Example 1, the mass ratio of p-hydroxybenzoic acid to 2,6-naphthalenedicarboxylic acid is increased by 1. Other process parameters and operating conditions are exactly the same as in Example 1.

[0100] Comparative Example 2

[0101] This comparative example provides a method for preparing a high tensile strength polyester base fabric. The difference from Example 1 is that in step S1, the mass ratio of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid is adjusted to 1:0.7. Compared with Example 1, the mass ratio of p-hydroxybenzoic acid to 2,6-naphthalenedicarboxylic acid is reduced by 1. Other process parameters and operating conditions are exactly the same as in Example 1.

[0102] Comparative Example 3

[0103] This comparative example provides a method for preparing a high tensile strength polyester base fabric. The difference from Example 1 is that in step S3, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is adjusted to 2.4:1. Compared with Example 1, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is increased by 1. Other process parameters and operating conditions are exactly the same as in Example 1.

[0104] Comparative Example 4

[0105] This comparative example provides a method for preparing a high tensile strength polyester base fabric. The difference from Example 1 is that in step S3, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is adjusted to 0.4:1. Compared to Example 1, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is reduced by 1. Other process parameters and operating conditions are exactly the same as in Example 1. The mechanical property test results of the polyester base fabrics prepared in Examples 1-4 and Comparative Examples 1-4 of this invention are shown in Table 1.

[0106] Table 1. Test results of high tensile strength polyester base fabrics prepared in Examples 1-4 and Comparative Examples 1-4

[0107]

[0108] As can be seen from the data in the table, compared with Example 1, the tensile strength (longitudinal) of Comparative Example 1 increased, while the elongation at break (longitudinal), tensile strength (transverse), and elongation at break (transverse) decreased; the tensile strength (longitudinal) of Comparative Example 2 decreased, while the elongation at break (longitudinal), tensile strength (transverse), and elongation at break (transverse) increased. This is because the mass of p-hydroxybenzoic acid increased in Comparative Example 1. When the content is too high, the rigidity of the modified liquid crystal polyester is enhanced, and the linearity of the molecular chain is stronger, thus significantly improving the longitudinal tensile strength. Excessive rigidity also leads to a decrease in the bonding force between molecular chains, reducing the material's resistance to transverse stress, thus decreasing the transverse tensile strength. Excessive p-hydroxybenzoic acid content leads to excessively high molecular chain rigidity, restricting the bending and stretching ability of chain segments, thus reducing the longitudinal elongation at break. The molecular chain bonding in the transverse direction is already weak, and an excessively high proportion of p-hydroxybenzoic acid further leads to poor ductility in the transverse direction, resulting in a decrease in the transverse elongation at break. In Comparative Example 2, when the content is too low, the modified liquid crystal polyester is not formed sufficiently, the rigidity and linearity of the molecular chain are weakened, resulting in a decrease in longitudinal tensile strength. A decrease in the proportion will weaken the rigidity of the molecular chain, while increasing the flexibility and entanglement ability of the molecular chain, which will enhance the transverse molecular chain force to a certain extent, thus increasing the transverse tensile strength. A decrease in the content of p-hydroxybenzoic acid will reduce the rigidity of the molecular chain, increase the rotation and bending ability of the molecular chain, thereby increasing the longitudinal elongation at break. An increase in the proportion of flexible segments will increase the transverse elongation at break.

[0109] Compared to Example 1, Comparative Example 3 showed a decrease in tensile strength (longitudinal), and an increase in elongation at break (longitudinal), tensile strength (transverse), and elongation at break (transverse); while Comparative Example 2 showed an increase in tensile strength (longitudinal), and a decrease in elongation at break (longitudinal), tensile strength (transverse), and elongation at break (transverse). This is because the increased mass of polyethylene glycol monomethyl ether in Comparative Example 3 increases the proportion of flexible polyether segments, reducing the overall rigidity of the material, weakening the linearity of the molecular chains, and decreasing the longitudinal tensile strength. The increase in flexible segments helps improve the ductility and bonding force of the transverse molecular chains, thus increasing the transverse tensile strength. Due to the increased proportion of flexible segments, the molecular chains are easier to bend and slip, improving the material's ductility and increasing the longitudinal elongation at break. The increased proportion of flexible segments in the transverse direction allows the molecular chains to better disperse stress in the transverse direction, improving the transverse elongation at break.

[0110] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a high tensile strength polyester base fabric, characterized in that, The preparation method is as follows: Step S1: Mix 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid, add 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, heat to a first temperature under nitrogen protection to react fully, cool to room temperature after the reaction is complete, and vacuum dry at a second temperature to obtain modified liquid crystal polyester; Step S2: Disperse poly(p-phenylenebenzobisoxazole) in methanesulfonic acid to obtain a poly(p-phenylenebenzobisoxazole) solution. Add polyetheramine and silane coupling agent, stir at a first stirring speed, and then vacuum dry at a second temperature to obtain modified poly(p-phenylenebenzobisoxazole). Step S3: Under a nitrogen atmosphere, polyethylene glycol monomethyl ether is heated to a third temperature, maleic anhydride, p-toluenesulfonic acid and hydroquinone are added, the temperature is raised to a fourth temperature to fully react, the temperature is adjusted to a fifth temperature, acrylic acid and benzoyl peroxide are added to continue the reaction, the temperature is further adjusted to a sixth temperature, epichlorohydrin and tetrabutylammonium bromide are added to continue the reaction, and modified polyethylene glycol monomethyl ether is obtained. Step S4: Add the dicarboxylic acid mixture to the diol mixture, then add the modified liquid crystal polyester and the modified poly(p-phenylenebenzobisoxazole). Under nitrogen protection, heat to the seventh temperature and stir the reaction at the second stirring speed. Adjust the temperature to the eighth temperature, add the modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether diol and stir evenly. Then add antimony acetate, tetrapropyl zirconate and triethyl phosphate and react fully. After the reaction is complete, adjust the temperature to the seventh temperature, and add trimethylolpropane triacrylate, triisocyanate, hindered phenolic antioxidant and phosphite in sequence. After stirring evenly, extrude to obtain the modified polyester. Step S5: The modified polyester is vacuum dried at a sixth temperature, and then the dried modified polyester is heated to a first temperature. The nascent fibers formed by meltblowing are split and spun into a fiber web. The fiber web is reinforced by pre-needling and main needle punching, and then cut and rolled to obtain a polyester base fabric semi-finished product. The polyester base fabric semi-finished product is heat-set, impregnated with glue, dried and then finished to obtain a high tensile strength polyester base fabric.

2. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S1, The mass ratio of 2,6-naphthalenedicarboxylic acid to p-hydroxybenzoic acid is 1:(1.5-2); The mass of the 4,4'-dihydroxybiphenyl is 8-12% of the total mass of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid; The mass of the acetoxybenzoic acid is 4-6% of the total mass of 2,6-naphthalenedicarboxylic acid and p-hydroxybenzoic acid; The first temperature is 285-295℃; The reaction time at the first temperature is 1.5-2.5 hours; The second temperature is 115-125℃; The vacuum drying time is 7-9 hours.

3. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S2, The mass fraction of the poly(p-phenylenebenzobisoxazole) solution is 8-12 wt.%. The mass of the polyetheramine is 4-6% of the poly(p-phenylenebenzobisoxazole); The silane coupling agent is silane coupling agent KH-550, and the mass of silane coupling agent KH-550 is 1.5-2.5% of poly(p-phenylenebenzobisoxazole). The first stirring speed is 200-300 rpm; The stirring time is 1-2 hours; The vacuum drying time is 7-9 hours.

4. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S3, The mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is (1.2-1.7):1; The mass of the p-toluenesulfonic acid is 0.1-0.2% of the mass of polyethylene glycol monomethyl ether; The mass of hydroquinone is 0.05-0.1% of the mass of polyethylene glycol monomethyl ether; The fourth temperature is 165-175℃; The reaction time at the fourth temperature is 2.5-3.0 hours; The fifth temperature is 140-150℃.

5. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S3, The mass of the acrylic acid is 9-11% of the mass of polyethylene glycol monomethyl ether; The mass of benzoyl peroxide is 0.3-0.5% of the mass of acrylic acid; The reaction time at the fifth temperature is 1.5-2.0 hours; The sixth temperature is 110-120℃; The mass of epichlorohydrin is 2.5-3.5% of the mass of polyethylene glycol monomethyl ether; The mass of the tetrabutylammonium bromide is 1.0-1.2% of the mass of epichlorohydrin; The reaction time at the sixth temperature is 4-5 hours.

6. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S4, The dicarboxylic acid mixture consists of terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,5-furandicarboxylic acid, in a mass ratio of 18:1:

1. The diol mixture consists of ethylene glycol, 1,4-cyclohexanediol, and neopentyl glycol, in a mass ratio of 15:2:

1. The mass ratio of the diformic acid mixture to the diol mixture is 1:2; The modified liquid crystal polyester comprises 1.8-2.2% of the total mass of the dicarboxylic acid mixture and the diol mixture; The modified poly(p-phenylenebenzobisoxazole) is 0.8-1.2% of the total mass of the dicarboxylic acid mixture and the diol mixture; The seventh temperature is 230-240℃; The second stirring speed is 100-200 rpm; The reaction time at the second stirring speed is 3-4 hours; The eighth temperature is 270-280℃.

7. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, In step S4, the modified polyethylene glycol monomethyl ether accounts for 1.3-1.7% of the total mass of the dicarboxylic acid mixture and the glycol mixture; the polytetrahydrofuran ether diol accounts for 1.3-1.7% of the total mass of the dicarboxylic acid mixture and the glycol mixture; and the antimony acetate accounts for 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the glycol mixture. The mass of the tetrapropyl zirconate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the diol mixture; The mass of the triethyl phosphate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the diol mixture; The reaction time for adding triethyl phosphate is 4-5 hours.

8. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S4, the mass of the trimethylolpropane triacrylate is 0.4-0.6% of the total mass of the dicarboxylic acid mixture and the diol mixture; The mass of the triisocyanate is 0.2-0.4% of the total mass of the dicarboxylic acid mixture and the diol mixture; The hindered phenolic antioxidant is 0.15-0.25% of the total mass of the dicarboxylic acid mixture and the diol mixture, and the hindered phenolic antioxidant is antioxidant 1010; The mass of the phosphite is 0.6-0.8% of the total mass of the dicarboxylic acid mixture and the diol mixture.

9. The method for preparing a high tensile strength polyester base fabric according to claim 1, characterized in that, Step S5, the sixth temperature is 110-120℃; The vacuum drying time is 8-10 hours.

10. A high tensile strength polyester base fabric obtained by the preparation method according to any one of claims 1-9.

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