High-tensile-strength polyester base cloth and preparation method thereof

Abstract

The invention belongs to the field of polyester base cloth materials, provides high-tensile-strength polyester base cloth and a preparation method thereof, and constructs modified polyester which can keep excellent mechanical properties under a high stress condition. Firstly, polyethylene glycol monomethyl ether and maleic anhydride are subjected to an esterification reaction, a flexible polyether chain segment and an unsaturated double-bond structure are introduced, and then functional groups are introduced through free radical grafting of acrylic acid and a ring-opening reaction of epoxy chloropropane, so that the flexible chain segment has reactivity with a polyester chain and other components; therefore, the intermolecular compatibility and binding force are enhanced in subsequent polymerization. In the preparation process of a polyester matrix, modified liquid crystal polyester and modified poly (p-phenylene benzobisoxazole) are added, the tensile strength of the material is improved through a rigid molecular chain structure of the modified liquid crystal polyester and the modified poly (p-phenylene benzobisoxazole), and meanwhile, flexible chain segments of modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether glycol effectively disperse internal stress, so that the tensile strength of the material is improved. The overall mechanical property and the structural stability of the material are further improved.

Description

Technical Field

[0001] The invention belongs to the field of polyester tire base cloth materials and relates to a high-tensile strength polyester tire base cloth and a preparation method thereof. Background Art

[0002] Polyester tire base fabric is an important industrial material, which is widely used in tires, conveyor belts, composite materials and other high-performance products. In recent years, with the rapid development of the automobile industry and high-performance materials, the performance requirements of polyester tire base fabrics have been continuously improved, especially in terms of tensile strength. The patent with publication number CN115418798A discloses a production process of high-strength polyester filament tire base fabric, which produces a high-strength polyester filament tire base fabric semi-finished product by polyester spunbonding and needle punching reinforcement, and then through the dipping and shaping process, finally obtains a high-strength polyester filament tire base fabric product. The patent directly produces polyester chips as raw materials, but the mechanical strength of the obtained 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 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] In view of the deficiencies in the prior art, the object of the present invention is to provide a high tensile strength polyester tire base cloth and a preparation method thereof, wherein flexible segments and functional groups are introduced through esterification with maleic anhydride, free radical grafting of acrylic acid, and chemical reaction of epichlorohydrin, and modified liquid crystal polyester and modified poly(p-phenylene benzobisoxazole) are embedded into the polyester matrix, giving the material better tensile strength and intermolecular bonding force, and utilizing the synergistic effect of flexible polyether chains and rigid aromatic segments to achieve a balance between rigidity and flexibility, thereby improving toughness and avoiding brittle fracture, thereby meeting the needs of actual production.

[0004] To achieve this object, the present invention adopts the following technical solutions:

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

[0006] Step S1, mixing 2,6-naphthalene dicarboxylic acid and p-hydroxybenzoic acid, adding 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, heating to a first temperature under nitrogen protection for sufficient reaction, cooling to room temperature after the reaction, and drying under vacuum at a second temperature to obtain a modified liquid crystal polyester;

[0007] Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a poly(p-phenylene benzobisoxazole) solution, adding polyetheramine and silane coupling agent KH-550, stirring at a first stirring speed, and then vacuum drying at a second temperature to obtain a modified poly(p-phenylene benzobisoxazole);

[0008] Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to a third temperature, adding maleic anhydride, p-toluenesulfonic acid and hydroquinone, heating to a fourth temperature for sufficient reaction, adjusting the temperature to a fifth temperature, adding acrylic acid and benzoyl peroxide to continue the reaction, continuing to adjust the temperature to a sixth temperature, adding epichlorohydrin and tetrabutylammonium bromide to continue the reaction, and obtaining modified polyethylene glycol monomethyl ether;

[0009] Step S4, adding the dicarboxylic acid mixture to the diol mixture, then adding the modified liquid crystal polyester and the modified poly(p-phenylene benzobisoxazole), heating to the seventh temperature under nitrogen protection, stirring at the second stirring speed for reaction, adjusting the temperature to the eighth temperature, adding the modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether diol and stirring evenly, then adding antimony acetate, tetrapropyl zirconate, and triethyl phosphate to fully react, adjusting the temperature to the seventh temperature after the reaction is completed, adding trimethylolpropane triacrylate, triisocyanate, hindered phenol antioxidant, and phosphite in sequence, stirring evenly, and extruding to obtain the modified polyester;

[0010] Step S5, vacuum drying the modified polyester at the sixth temperature, and then heating the dried modified polyester to the first temperature, the primary fibers formed by meltblowing are formed into a fiber web through filament splitting and swinging, the fiber web is reinforced by pre-needling and main needling, and is cut and rolled to obtain a polyester tire base cloth semi-finished product, and the polyester tire base cloth semi-finished product is finished after heat setting, dipping, drying and then obtaining a polyester tire base cloth with high tensile strength.

[0011] The copolymerization reaction of 2,6-naphthalene dicarboxylic acid and p-hydroxybenzoic acid forms a polyester structure with liquid crystal properties. Liquid crystal polyester has a high molecular order and can provide stronger molecular chain orientation and crystallinity, thereby improving the mechanical properties of the fiber. Specifically, naphthalene dicarboxylic acid is an aromatic structure, which increases the rigidity of the polyester chain, making the synthesized polyester perform better in terms of mechanical strength. The naphthalene ring is a polycyclic aromatic structure composed of two conjugated benzene rings, with high planarity and high rigidity. The arrangement of the carboxyl group at the 2,6-position makes the ester bond formed by the molecule after the esterification reaction collinear with the plane of the naphthalene ring, so that the entire molecular chain is linear. The naphthalene ring in the molecular chain limits the free rotation of the molecule due to the π-π conjugation effect, making the chain segment linear in the molecular chain; the benzene ring is a typical aromatic ring with high symmetry and planarity. The para-hydroxyl and carboxyl groups in p-hydroxybenzoic acid are linearly arranged on the benzene ring. This symmetry makes the molecular chain formed after the esterification reaction remain highly linear. 4,4'-dihydroxybiphenyl is composed of two benzene rings connected by a single bond (biphenyl structure). The two benzene rings of the biphenyl structure tend to be coplanar in a static state. This coplanarity further improves the linearity and rigidity of the molecular chain. Through the esterification reaction, the two hydroxyl groups of 4,4'-dihydroxybiphenyl can be connected to different molecular chains respectively, playing the role of a "bridge" and further enhancing the regularity of the molecular chain. In the liquid crystal polyester molecule, the aromatic rings of 2,6-naphthalene dicarboxylic acid, p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl are connected by ester bonds. The ester bond has a certain conjugation effect. The orientation between the ester bond and the aromatic ring is restricted to a certain extent and tends to remain colinear with the aromatic ring. This restriction keeps the molecular chain highly linear, and ultimately forms a highly linear main chain.

[0012] Polyetheramine is a polymer obtained by the reaction of epoxy compounds and amine groups, containing multiple amine and ether structures. Poly(p-phenylene benzobisoxazole) is a polymer with high rigidity and high temperature resistance. The molecule contains p-phenylene (benzene ring) and bisoxazole ring. The bisoxazole ring is an aromatic heterocyclic compound containing nitrogen atoms. In the molecular structure of poly(p-phenylene benzobisoxazole), 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 segment to the poly(p-phenylene benzobisoxazole) molecular chain. The presence of the flexible region alleviates the excessive rigidity of the molecular chain, so that the material can more evenly disperse the internal stress under the action of external force, improve the fracture toughness of the material, and reduce the material failure caused by local segment breakage. In the bisoxazole ring of poly(p-phenylene benzobisoxazole), the lone pair of electrons on the nitrogen atom and the hydrogen atoms of the amine group can form hydrogen bonds to enhance the overall strength between the molecular chains. The amino groups in the silane coupling agent KH-550 molecule can chemically bond with the active sites on the surface of the poly(p-phenylene benzobisoxazole) molecular chain. The siloxane part of KH-550 can form covalent bonds or hydrogen bonds with other components, further improving the interface bonding force and optimizing the overall strength of the composite material.

[0013] Polyethylene glycol monomethyl ether is a common flexible segment material with a hydroxyl group at the end. Maleic anhydride is a compound with an acyl anhydride group. The anhydride group is a chemical functional group with high electrophilicity, which easily reacts with nucleophilic substances (such as hydroxyl groups) to produce a ring-opening reaction. The hydroxyl group at the end of polyethylene glycol monomethyl ether undergoes an esterification reaction with the anhydride group of maleic anhydride. The hydroxyl group at the end of polyethylene glycol monomethyl ether is esterified to an ester group. At the same time, the two acyl moieties of maleic anhydride are respectively connected to the ends of the polyethylene glycol monomethyl ether segment, introducing the ester group and double bond of maleic anhydride. Benzoyl peroxide decomposes into two benzoyl radicals under heating conditions. The generated free radicals initiate the double bonds in the esterification product of acrylic acid and polyethylene glycol monomethyl ether, undergo free radical addition reaction, graft acrylic acid onto the polyether chain, and form a carboxyl-containing side chain structure. The carboxyl group after acrylic acid grafting can form hydrogen bonds or covalent bonds with other components (such as epichlorohydrin, modified liquid crystal polyester), thereby enhancing the interaction force between molecular chains and enhancing tensile properties. Epichlorohydrin undergoes a ring-opening addition reaction with the remaining hydroxyl groups on the polyethylene glycol monomethyl ether molecular chain to form ether bonds and introduce epoxy groups. The introduction of epoxy groups can further undergo addition reactions with other functional groups (carboxyl, amino) in subsequent reactions to form a network cross-linked structure, thereby improving the overall mechanical properties of the material.

[0014] The dicarboxylic acid mixture reacts with the diol mixture to generate a polyester chain through a polycondensation reaction. Modified liquid crystal polyester and modified poly(p-phenylene benzobisoxazole) are introduced into the reaction system. These substances have the function of enhancing the orderly arrangement of polymer chains. The modified liquid crystal polyester can help the polyester fiber form a better orientation structure during the spinning process and improve the mechanical properties by providing a higher molecular arrangement order. The modified poly(p-phenylene benzobisoxazole) has a higher strength, and its introduction can improve the rigidity of the polyester and enhance the tensile strength. The terminal hydroxyl groups in the modified polyethylene glycol monomethyl ether and polytetramethylene ether diol undergo an esterification reaction with the carboxyl groups of the polyester molecular chain and are embedded in the polyester chain. The flexible segments in the modified polyethylene glycol monomethyl ether and polytetramethylene ether diol can disperse the internal stress in the material and improve the toughness of the material.

[0015] As a preferred technical solution of the present invention, in step S1, the mass ratio of 2,6-naphthalene dicarboxylic 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 is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] In some optional examples, the mass of the 4,4'-dihydroxybiphenyl is 8-12% of the total mass of 2,6-naphthalene dicarboxylic 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 the numerical range are also applicable.

[0017] In some optional examples, the mass of the acetoxybenzoic acid is 4-6% of the total mass of 2,6-naphthalene dicarboxylic acid and p-hydroxybenzoic acid, for example, it can 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 the numerical range are also applicable.

[0018] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0020] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

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

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

[0023] In some optional examples, the mass of the polyetheramine is 4-6% of the poly(p-phenylene benzobisoxazole), 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, and other unlisted values ​​within the numerical range are also applicable.

[0024] In some optional examples, the mass of the silane coupling agent KH-550 is 1.5-2.5% of the poly(p-phenylene benzobisoxazole), 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 the numerical range are also applicable.

[0025] In some optional examples, the first stirring speed is 200-300 rpm, for example, it can be 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 the numerical range are also applicable.

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

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

[0029] In some optional examples, the mass of the p-toluenesulfonic acid is 0.1-0.2% of the mass of polyethylene glycol monomethyl ether, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0031] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0033] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

[0034] In some optional examples, 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, and other unlisted values ​​within the numerical range are also applicable.

[0035] In some optional examples, the mass of the benzoyl peroxide is 0.3-0.5% of the mass of acrylic acid, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

[0036] In some optional examples, the reaction time at the fifth temperature is 1.5-2.0 h, for example, 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, and other unlisted values ​​within the numerical range are also applicable.

[0037] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

[0038] In some optional examples, 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, and other unlisted values ​​within the numerical range are also applicable.

[0039] In some optional examples, the mass of the tetrabutylammonium bromide is 1.0-1.2% of the mass of epichlorohydrin, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

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

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

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

[0043] In some optional examples, the mass ratio of the diformic acid mixture to the diol mixture is 1:2.

[0044] In some optional 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 the numerical range are also applicable.

[0045] In some optional examples, the mass of the modified poly(p-phenylene benzobisoxazole) is 0.8-1.2% of the total mass of the dicarboxylic acid mixture and the diol mixture, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

[0046] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

[0047] In some optional examples, 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0049] In some optional 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, and other unlisted values ​​within the numerical range are also applicable.

[0050] In some optional examples, 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 the numerical range are also applicable.

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

[0052] In some optional examples, the mass of the antimony acetate is 0.02-0.04% of the total mass of the diformic acid mixture and the glycol mixture, for example, it can 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 the numerical range are also applicable.

[0053] In some optional examples, the mass of the tetrapropyl zirconate is 0.02-0.04% of the total mass of the dicarboxylic acid mixture and the glycol mixture, for example, it can 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 the numerical range are also applicable.

[0054] In some optional examples, the mass of the triethyl phosphate is 0.02-0.04% of the total mass of the diformic acid mixture and the diol mixture, for example, it can 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 the numerical range are also applicable.

[0055] In some optional examples, the reaction time of adding triethyl phosphate is 4-5h, for example, it can be 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] In some optional examples, the mass of the trimethylolpropane triacrylate is 0.4-0.6% of the total mass of the dicarboxylic acid mixture and the glycol mixture, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

[0057] In some optional examples, the mass of the triisocyanate is 0.2-0.4% of the total mass of the diformic acid mixture and the diol mixture, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

[0058] In some optional examples, the mass of the hindered phenol antioxidant is 0.15-0.25% of the total mass of the dicarboxylic acid mixture and the glycol mixture, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable. The hindered phenol antioxidant is antioxidant 1010.

[0059] In some optional examples, the mass of the phosphite is 0.6-0.8% of the total mass of the diformic acid mixture and the glycol mixture, for example, it can 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, and other unlisted values ​​within the numerical range are also applicable.

[0060] As a preferred technical solution of the present invention, in step S5, 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0062] In a second aspect, the present invention provides a high tensile strength polyester tire base cloth obtained by the preparation method described in the first aspect.

[0063] Compared with the prior art, the present invention has the following beneficial effects: (1) by introducing the copolymerization reaction of 2,6-naphthalene dicarboxylic acid and p-hydroxybenzoic acid, a polyester structure with liquid crystal properties is formed. The liquid crystal polyester has a high degree of molecular order. The highly ordered arrangement of the molecular chains can enhance the interaction between molecules, reduce molecular chain slippage, maintain higher mechanical stability during stretching, and improve tensile strength; (2) by introducing flexible segments (flexible polyether segments generated by the reaction of polyethylene glycol monomethyl ether and maleic anhydride), the flexibility of the fiber is improved. These flexible segments provide adjustable elasticity for the polyester molecules, so that the fiber can deform to a certain extent under stretching and impact, reducing the occurrence of brittle fracture, and the fiber has better ductility and impact resistance under load; (3) acrylic acid is grafted onto the polyether chain to form a structure with carboxyl side chains. The carboxyl group can form hydrogen bonds or covalent bonds, thereby greatly enhancing the interaction between the molecular chains and further improving the mechanical properties of the fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A flow chart of a method for preparing a high tensile strength polyester tire base cloth provided in Examples 1-4 of the present invention;

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

[0066] Figure 3 This is a TEM image of the high tensile strength polyester tire base fabric prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

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

[0069] Example 1

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

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

[0072] Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a 9.6wt.% poly(p-phenylene benzobisoxazole) solution, adding 4.6% of polyetheramine relative to the mass of poly(p-phenylene benzobisoxazole) and 1.7% of silane coupling agent KH-550 relative to the mass of poly(p-phenylene benzobisoxazole), stirring at 220rpm for 1.4h, and vacuum drying at 118°C for 7.4h to obtain modified poly(p-phenylene benzobisoxazole);

[0073] Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to 129° C., adding maleic anhydride, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is 1.4:1, adding 0.14% of p-toluenesulfonic acid and 0.06% of hydroquinone relative to the mass of polyethylene glycol monomethyl ether, heating to 168° C. to fully react for 2.7 hours, adjusting the temperature to 145° C., adding 9.7% of acrylic acid relative to the mass of polyethylene glycol monomethyl ether and 0.38% of benzoyl peroxide relative to the mass of polyethylene glycol monomethyl ether, and continuing to react for 1.6 hours, continuing to adjust the temperature to 114° C., adding 2.9% of epichlorohydrin relative to the mass of polyethylene glycol monomethyl ether and 1.08% of tetrabutylammonium bromide relative to the mass of epichlorohydrin, and continuing to react for 4.6 hours to obtain modified polyethylene glycol monomethyl ether;

[0074] Step S4, adding a mixture of terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 2,5-furan dicarboxylic acid in a mass ratio of 18:1:1 to a mixture of ethylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol in a mass ratio of 15:2:1, the mass ratio of the dicarboxylic acid mixture to the diol mixture is 1:2, and then adding 1.9% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture and 0.88% of the modified poly(p-phenylene benzobisoxazole) relative to the total mass of the dicarboxylic acid mixture and the diol mixture. Under nitrogen protection, the temperature is raised to 234° C., and the reaction is stirred at a speed of 140 rpm for 3.3 hours. The temperature is adjusted to 273° C., and the dicarboxylic acid mixture and the diol mixture are added. 1.46% of the total weight of the alcohol mixture is modified polyethylene glycol monomethyl ether and 1.37% of polytetrahydrofuran ether diol relative to the total weight of the dicarboxylic acid mixture and the diol mixture is mixed evenly, and then 0.02% of antimony acetate, 0.03% of tetrapropyl zirconate and 0.03% of triethyl phosphate relative to the total weight of the dicarboxylic acid mixture and the diol mixture are added to fully react for 4.3 hours. After the reaction is completed, the temperature is adjusted to 235° C., and 0.47% of trimethylolpropane triacrylate, 0.29% of triisocyanate, 0.18% of antioxidant 1010 and 0.65% of phosphite relative to the total weight of the dicarboxylic acid mixture and the diol mixture are added in sequence, and the mixture is stirred evenly and extruded to obtain a modified polyester;

[0075] Step S5, vacuum drying the modified polyester at 115°C for 8.6 hours, then heating the dried modified polyester to 288°C, forming a fiber web through splitting and swinging of the primary fibers formed by meltblowing, reinforcing the fiber web by pre-needling and main needling, cutting and winding to obtain a polyester tire base cloth semi-finished product, and finishing the polyester tire base cloth semi-finished product by heat setting, dipping in glue, and drying to obtain a polyester tire base cloth with high tensile strength.

[0076] Figure 2 This is a SEM image of the high tensile strength polyester tire base fabric prepared in this embodiment. It can be seen 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 tire base fabric prepared in this embodiment.

[0077] Example 2

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

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

[0080] Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a 11.2wt.% poly(p-phenylene benzobisoxazole) solution, adding 5.2% of polyetheramine relative to the mass of poly(p-phenylene benzobisoxazole) and 2.1% of silane coupling agent KH-550 relative to the mass of poly(p-phenylene benzobisoxazole), stirring at 240 rpm for 1.3 h, and vacuum drying at 117° C. for 7.5 h to obtain a modified poly(p-phenylene benzobisoxazole);

[0081] Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to 127° C., adding maleic anhydride, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride is 1.3:1, adding 0.18% of p-toluenesulfonic acid and 0.05% of hydroquinone relative to the mass of polyethylene glycol monomethyl ether, heating to 172° C. and fully reacting for 2.5 hours, adjusting the temperature to 148° C., adding 10.3% of acrylic acid relative to the mass of polyethylene glycol monomethyl ether and 0.46% of benzoyl peroxide relative to the mass of polyethylene glycol monomethyl ether, and continuing to react for 1.5 hours, continuing to adjust the temperature to 118° C., adding 3.3% of epichlorohydrin relative to the mass of polyethylene glycol monomethyl ether and 1.04% of tetrabutylammonium bromide relative to the mass of epichlorohydrin, and continuing to react for 4.3 hours to obtain modified polyethylene glycol monomethyl ether;

[0082] Step S4, adding a mixture of terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 2,5-furan dicarboxylic acid in a mass ratio of 18:1:1 to a mixture of ethylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol in a mass ratio of 15:2:1, wherein the mass ratio of the dicarboxylic acid mixture to the diol mixture is 1:2, and then adding 2.2% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture and 0.96% of the modified poly(p-phenylene benzobisoxazole) relative to the total mass of the dicarboxylic acid mixture and the diol mixture, and under nitrogen protection, heating to 238° C., stirring at 180 rpm for 3.8 h, adjusting the temperature to 277° C., adding 0.5% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture, and reacting for 3.8 h at a stirring speed of 180 rpm, adjusting the temperature to 277° C., and adding 0.5% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture. 1.53% of the total mass of the alcohol mixture is modified polyethylene glycol monomethyl ether and 1.46% of polytetrahydrofuran ether diol relative to the total mass of the dicarboxylic acid mixture and the diol mixture is mixed evenly, and then 0.03% of antimony acetate, 0.02% of tetrapropyl zirconate and 0.02% of triethyl phosphate relative to the total mass of the dicarboxylic acid mixture and the diol mixture are added to fully react for 4.2 hours. After the reaction is completed, the temperature is adjusted to 238° C., and 0.51% of trimethylolpropane triacrylate, 0.37% of triisocyanate, 0.19% of antioxidant 1010 and 0.74% of phosphite relative to the total mass of the dicarboxylic acid mixture and the diol mixture are added in sequence, and the mixture is stirred evenly and extruded to obtain a modified polyester;

[0083] Step S5, vacuum drying the modified polyester at 119°C for 9.9h, then heating the dried modified polyester to 295°C, forming a fiber web through the process of splitting and swinging the primary fibers formed by meltblowing, reinforcing the fiber web by pre-needling and main needling, cutting and winding to obtain a polyester tire base cloth semi-finished product, and finishing the polyester tire base cloth semi-finished product by heat setting, dipping in glue, and drying to obtain a polyester tire base cloth with high tensile strength.

[0084] Example 3

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

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

[0087] Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a 10.4wt.% poly(p-phenylene benzobisoxazole) solution, adding 5.6% of polyetheramine relative to the mass of poly(p-phenylene benzobisoxazole) and 2.3% of silane coupling agent KH-550 relative to the mass of poly(p-phenylene benzobisoxazole), stirring at 280 rpm for 1.7 hours, and vacuum drying at 123° C. for 8.2 hours to obtain modified poly(p-phenylene benzobisoxazole);

[0088] Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to 132° C., adding maleic anhydride, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride being 1.6:1, adding 0.12% of p-toluenesulfonic acid and 0.09% of hydroquinone relative to the mass of polyethylene glycol monomethyl ether, heating to 175° C. and fully reacting for 3.0 h, adjusting the temperature to 142° C., adding 10.7% of acrylic acid relative to the mass of polyethylene glycol monomethyl ether and 0.41% of benzoyl peroxide relative to the mass of polyethylene glycol monomethyl ether, and continuing to react for 1.9 h, continuing to adjust the temperature to 116° C., adding 3.1% of epichlorohydrin relative to the mass of polyethylene glycol monomethyl ether and 1.12% of tetrabutylammonium bromide relative to the mass of epichlorohydrin, and continuing to react for 4.9 h to obtain modified polyethylene glycol monomethyl ether;

[0089] Step S4, adding a mixture of terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 2,5-furan dicarboxylic acid in a mass ratio of 18:1:1 to a mixture of ethylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol in a mass ratio of 15:2:1, wherein the mass ratio of the dicarboxylic acid mixture to the diol mixture is 1:2, and then adding 2.1% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture and 1.13% of the modified poly(p-phenylene benzobisoxazole) relative to the total mass of the dicarboxylic acid mixture and the diol mixture, heating to 231° C. under nitrogen protection, stirring at 190 rpm for 3.5 h, adjusting the temperature to 275° C., adding 1.13% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture, and reacting for 3.5 h at a stirring speed of 190 rpm, adjusting the temperature to 275° C., and adding 1.13% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture. 1.66% of the total mass of the alcohol mixture is modified polyethylene glycol monomethyl ether and 1.54% of polytetrahydrofuran ether diol relative to the total mass of the dicarboxylic acid mixture and the diol mixture is mixed evenly, and then 0.04% of antimony acetate, 0.04% of tetrapropyl zirconate and 0.04% of triethyl phosphate relative to the total mass of the dicarboxylic acid mixture and the diol mixture are added to fully react for 4.9 hours. After the reaction is completed, the temperature is adjusted to 236° C., and 0.59% of trimethylolpropane triacrylate, 0.31% of triisocyanate, 0.23% of antioxidant 1010 and 0.73% of phosphite relative to the total mass of the dicarboxylic acid mixture and the diol mixture are added in sequence, and the mixture is stirred evenly and extruded to obtain a modified polyester;

[0090] Step S5, vacuum drying the modified polyester at 120°C for 9.2h, then heating the dried modified polyester to 291°C, forming a fiber web through splitting and swinging of the primary fibers formed by meltblowing, reinforcing the fiber web by pre-needling and main needling, cutting and rolling to obtain a polyester tire base cloth semi-finished product, and finishing the polyester tire base cloth semi-finished product by heat setting, dipping in glue, and drying to obtain a polyester tire base cloth with high tensile strength.

[0091] Example 4

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

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

[0094] Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a 8.6wt.% poly(p-phenylene benzobisoxazole) solution, adding 4.9% of polyetheramine relative to the mass of poly(p-phenylene benzobisoxazole) and 1.7% of silane coupling agent KH-550 relative to the mass of poly(p-phenylene benzobisoxazole), stirring at 270rpm for 1.9h, and vacuum drying at 121°C for 7.8h to obtain modified poly(p-phenylene benzobisoxazole);

[0095] Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to 130° C., adding maleic anhydride, the mass ratio of polyethylene glycol monomethyl ether to maleic anhydride being 1.5:1, adding 0.13% of p-toluenesulfonic acid and 0.06% of hydroquinone relative to the mass of polyethylene glycol monomethyl ether, heating to 166° C. and fully reacting for 2.9 hours, adjusting the temperature to 150° C., adding 9.8% of acrylic acid relative to the mass of polyethylene glycol monomethyl ether and 0.39% of benzoyl peroxide relative to the mass of polyethylene glycol monomethyl ether, and continuing to react for 1.8 hours, continuing to adjust the temperature to 119° C., adding 2.6% of epichlorohydrin relative to the mass of polyethylene glycol monomethyl ether and 1.03% of tetrabutylammonium bromide relative to the mass of epichlorohydrin, and continuing to react for 4.1 hours to obtain modified polyethylene glycol monomethyl ether;

[0096] Step S4, adding a mixture of terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 2,5-furan dicarboxylic acid in a mass ratio of 18:1:1 to a mixture of ethylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol in a mass ratio of 15:2:1, wherein the mass ratio of the dicarboxylic acid mixture to the diol mixture is 1:2, and then adding 2.0% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture and 0.91% of the modified poly(p-phenylene benzobisoxazole) relative to the total mass of the dicarboxylic acid mixture and the diol mixture, and under nitrogen protection, heating to 232° C., stirring at 120 rpm for 3.9 hours, adjusting the temperature to 279° C., adding 0.5% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture, and reacting for 3.9 hours at a stirring speed of 120 rpm, and adjusting the temperature to 279° C., and adding 0.5% of the modified liquid crystal polyester relative to the total mass of the dicarboxylic acid mixture and the diol mixture. 1.7% of the total mass of the alcohol mixture is modified polyethylene glycol monomethyl ether and 1.63% of polytetrahydrofuran ether diol relative to the total mass of the diformic acid mixture and the diol mixture is mixed evenly, and then 0.03% of antimony acetate, 0.02% of tetrapropyl zirconate and 0.02% of triethyl phosphate relative to the total mass of the diformic acid mixture and the diol mixture are added to fully react for 4.5 hours. After the reaction is completed, the temperature is adjusted to 234° C., and 0.57% of trimethylolpropane triacrylate, 0.29% of triisocyanate, 0.24% of antioxidant 1010 and 0.62% of phosphite relative to the total mass of the diformic acid mixture and the diol mixture are added in sequence, and the mixture is stirred evenly and extruded to obtain a modified polyester;

[0097] Step S5, vacuum drying the modified polyester at 113°C for 8.7h, then heating the dried modified polyester to 286°C, forming a fiber web through splitting and swinging of the primary fibers formed by meltblowing, reinforcing the fiber web by pre-needling and main needling, cutting and winding to obtain a polyester tire base cloth semi-finished product, and finishing the polyester tire base cloth semi-finished product by heat setting, dipping in glue, and drying to obtain a polyester tire base cloth with high tensile strength.

[0098] Comparative Example 1

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

[0100] Comparative Example 2

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

[0102] Comparative Example 3

[0103] This comparative example provides a method for preparing a high tensile strength polyester tire base cloth. The difference from Example 1 is that in step S3, the mass ratio of maleic anhydride to polyethylene glycol monomethyl ether 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, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0104] Comparative Example 4

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

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

[0107]

[0108] From the data in the table, it can be seen that compared with Example 1, the tensile strength (longitudinal) of Comparative Example 1 increases, and the elongation at break (longitudinal), tensile strength (transverse) and elongation at break (transverse) decrease; the tensile strength (longitudinal) of Comparative Example 2 decreases, and the elongation at break (longitudinal), tensile strength (transverse) and elongation at break (transverse) increase. This is because the mass of p-hydroxybenzoic acid in Comparative Example 1 increases, and when the content is too much, the rigidity of the modified liquid crystal polyester is enhanced, and the linearity of the molecular chain is stronger, thereby significantly improving the longitudinal tensile strength; excessive rigidity will also lead to a decrease in the bonding force between molecular chains, reducing the material's resistance to transverse stress, so the transverse tensile strength decreases; excessive p-hydroxybenzoic acid content will lead to excessive rigidity of the molecular chain, limiting the bending and stretching ability of the chain segment, thereby reducing the longitudinal elongation at break; the molecular chain bonding in the transverse direction itself is weak, and the excessive proportion of p-hydroxybenzoic acid further leads to poor ductility in the transverse direction, and the transverse elongation at break decreases. In Comparative Example 2, when the content is too little, the modified liquid crystal polyester is insufficiently formed, the rigidity and linearity of the molecular chain are weakened, and the longitudinal tensile strength decreases; a decrease in the ratio will weaken the rigidity of the molecular chain, while increasing the flexibility and entanglement ability of the molecular chain, and to a certain extent, increase the force of the lateral molecular chain, thereby improving the lateral tensile strength; a reduction in the content of parahydroxybenzoic acid will reduce the rigidity of the molecular chain, increase the rotation and bending ability of the molecular chain, and thus increase the longitudinal elongation at break; an increase in the proportion of flexible segments increases the transverse elongation at break.

[0109] Compared with Example 1, the tensile strength (longitudinal) of Comparative Example 3 is reduced, and the elongation at break (longitudinal), tensile strength (transverse) and elongation at break (transverse) are increased; the tensile strength (longitudinal) of Comparative Example 2 is increased, and the elongation at break (longitudinal), tensile strength (transverse) and elongation at break (transverse) are reduced. This is because the mass of polyethylene glycol monomethyl ether in Comparative Example 3 increases, which increases the proportion of flexible polyether segments, reduces the overall rigidity of the material, weakens the linearity of the molecular chain, and reduces the longitudinal tensile strength; the increase in the flexible segment helps to improve the ductility and bonding force of the transverse molecular chain, so the transverse tensile strength is improved; due to the increase in the proportion of flexible segments, the molecular chain is easier to bend and slip, the ductility of the material is improved, and the longitudinal elongation at break is increased; the proportion of flexible segments in the transverse direction increases, so that the molecular chain can better disperse stress in the transverse direction and improve the transverse elongation at break.

[0110] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a high tensile strength polyester tire base fabric, characterized in that: The preparation method is: Step S1, mixing 2,6-naphthalene dicarboxylic acid and p-hydroxybenzoic acid, adding 4,4'-dihydroxybiphenyl and acetoxybenzoic acid, heating to a first temperature under nitrogen protection for sufficient reaction, cooling to room temperature after the reaction, and drying under vacuum at a second temperature to obtain a modified liquid crystal polyester; Step S2, dispersing poly(p-phenylene benzobisoxazole) in methanesulfonic acid to obtain a poly(p-phenylene benzobisoxazole) solution, adding polyetheramine and silane coupling agent, stirring at a first stirring speed, and then vacuum drying at a second temperature to obtain a modified poly(p-phenylene benzobisoxazole); Step S3, under a nitrogen atmosphere, heating polyethylene glycol monomethyl ether to a third temperature, adding maleic anhydride, p-toluenesulfonic acid and hydroquinone, heating to a fourth temperature for sufficient reaction, adjusting the temperature to a fifth temperature, adding acrylic acid and benzoyl peroxide to continue the reaction, continuing to adjust the temperature to a sixth temperature, adding epichlorohydrin and tetrabutylammonium bromide to continue the reaction, and obtaining modified polyethylene glycol monomethyl ether; Step S4, adding the dicarboxylic acid mixture to the diol mixture, then adding the modified liquid crystal polyester and the modified poly(p-phenylene benzobisoxazole), heating to the seventh temperature under nitrogen protection, stirring at the second stirring speed for reaction, adjusting the temperature to the eighth temperature, adding the modified polyethylene glycol monomethyl ether and polytetrahydrofuran ether glycol and stirring evenly, then adding antimony acetate, tetrapropyl zirconate, and triethyl phosphate to fully react, adjusting the temperature to the seventh temperature after the reaction is completed, adding trimethylolpropane triacrylate, triisocyanate, hindered phenol antioxidant, and phosphite in sequence, stirring evenly, and extruding to obtain the modified polyester; Step S5, vacuum drying the modified polyester at the sixth temperature, and then heating the dried modified polyester to the first temperature, the primary fibers formed by meltblowing are formed into a fiber web through filament splitting and swinging, the fiber web is reinforced by pre-needling and main needling, and is cut and rolled to obtain a polyester tire base cloth semi-finished product, and the polyester tire base cloth semi-finished product is finished after heat setting, dipping, drying and then obtaining a polyester tire base cloth with high tensile strength.

2. The method for preparing a high tensile strength polyester tire base fabric according to claim 1, characterized in that: Step S1, The mass ratio of the 2,6-naphthalene dicarboxylic 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-naphthalene dicarboxylic acid and p-hydroxybenzoic acid; The first temperature is 285-295°C; The first temperature reaction time is 1.5-2.5h; The second temperature is 115-125°C; The vacuum drying time is 7-9h.

3. The method for preparing a high tensile strength polyester tire base fabric according to claim 1, characterized in that: Step S2, The mass fraction of the poly(p-phenylene benzobisoxazole) solution is 8-12wt.%; The mass of the polyetheramine is 4-6% of the poly(p-phenylene benzobisoxazole); 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-phenylene benzobisoxazole); The first stirring speed is 200-300 rpm; The stirring time is 1-2h; The vacuum drying time is 7-9h.

4. The method for preparing a high tensile strength polyester tire 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 the hydroquinone is 0.05-0.1% of the mass of polyethylene glycol monomethyl ether; The fourth temperature is 165-175°C; The reaction time of the fourth temperature is 2.5-3.0h; The fifth temperature is 140-150°C.

5. The method for preparing a high tensile strength polyester tire 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 the benzoyl peroxide is 0.3-0.5% of the mass of the acrylic acid; The reaction time of the fifth temperature is 1.5-2.0h; The sixth temperature is 110-120° C. 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 4-5h.

6. The method for preparing a high tensile strength polyester tire base fabric according to claim 1, characterized in that: Step S4, The dicarboxylic acid mixture is terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 2,5-furan dicarboxylic acid, respectively, with a mass ratio of 18:1:1; The diol mixture is ethylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol, with a mass ratio of 15:2:1; The mass ratio of the dicarboxylic acid mixture to the diol mixture is 1:2; 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; The mass of the modified poly(p-phenylene benzobisoxazole) is 0.8-1.2% of the total mass of the dicarboxylic acid mixture and the diol mixture; The seventh temperature is 230-240°C; The second stirring speed is 100-200 rpm; The reaction time of the second stirring speed is 3-4h; The eighth temperature is 270-280°C.

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

8. The method for preparing a high tensile strength polyester tire 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 diformic acid mixture and the diol mixture; The mass of the triisocyanate is 0.2-0.4% of the total mass of the diformic acid mixture and the diol mixture; The mass of the hindered phenol antioxidant is 0.15-0.25% of the total mass of the dicarboxylic acid mixture and the diol mixture, and the hindered phenol antioxidant is antioxidant 1010; The mass of the phosphite is 0.6-0.8% of the total mass of the diformic acid mixture and the diol mixture.

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

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

Images