Lightweight polyester tire and preparation method thereof

Abstract

The invention discloses a light-weight polyester tire and a preparation method thereof, and belongs to the technical field of fiber product treatment, and the preparation method of the light-weight polyester tire comprises the following steps: raw material preparation, spinning molding, tire base cloth molding and post-setting treatment. By adopting a melt direct spinning hollow fiber process, the gram weight of the base fabric is reduced by stabilizing a nitrogen core layer medium and controlling the hollow rate and fineness, the lightweight requirement is met, and the strength performance, the thermal stability and the weather resistance are also guaranteed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fiber product processing, and particularly relates to a lightweight polyester tire and a preparation method thereof. BACKGROUND

[0002] As a high-performance skeleton material, polyester tire is widely used in asphalt waterproofing membrane, geosynthetic material, building reinforcement material and other fields. Its core role is to provide excellent tensile strength, tear resistance and dimensional stability for the end product. With the deepening of the concept of energy saving and environmental protection and the upgrading demand of downstream application scenarios, lightweight has become an important development trend in the polyester tire industry. Lightweight polyester tire can significantly reduce the overall weight of the end product, reduce transportation and construction costs, and meet the development direction of green building materials. The market demand in the fields of building waterproofing and highway maintenance continues to rise.

[0003] In the process of lightweight development, the industry generally reduces the basis weight of the tire base cloth by optimizing the fiber forming process and adjusting the web density. Among them, the melt direct spinning hollow fiber process has become one of the mainstream technical paths to realize the lightweight of polyester tire because it can effectively reduce the material consumption of the solid part of the fiber. However, lightweight often comes with the challenge of material mechanical properties. How to reduce the grammage while ensuring that the polyester tire has enough tensile strength to resist external forces during construction and use is the focus of the industry. At the same time, polyester tire needs to withstand the combined effects of high temperature, humidity, solar ultraviolet radiation and other external factors in the actual use environment. The comprehensive weathering resistance directly determines the service life of the product. Insufficient thermal dimensional stability can lead to molecular chain rupture and creep of the material in a high temperature environment, causing shrinkage, wrinkling and other dimensional instability problems of the waterproofing membrane. Light-thermal aging can directly damage the polyester molecular structure, leading to irreversible degradation of mechanical properties. The introduction of hollow fibers not only reduces the material density, but also further exacerbates the above performance problems. On the one hand, the hollow structure is more prone to collapse and deformation under thermal stress, challenging the thermal dimensional stability. On the other hand, the relatively thin fiber wall material makes it more sensitive to external environmental factors, and it is more susceptible to performance degradation due to the cumulative effects of light, heat, oxygen and other multiple aging factors in long-term outdoor service, resulting in a decrease in strength and toughness, making it difficult to meet the long-term outdoor application requirements.

[0004] To solve the above problems, the industry tries to prepare the tire base fabric by using high-strength polyester filaments, trying to make up for the overall strength loss caused by lightweight by improving the strength of the monofilament, which improves the mechanical properties to some extent, but fails to balance the synergistic improvement of thermal dimensional stability and weather resistance; another technology tries to balance a single performance index by optimizing the spinning process parameters or adjusting the dipping latex formula, but often sacrifices one for the other, and it is difficult to achieve the overall synergy of lightweight and strength, thermal stability, weather resistance and other core performance. At present, the performance requirements of lightweight polyester tire on the market have gradually upgraded. Not only does it meet the green development needs of low weight, but it also puts forward strict standards for its key service performance, requiring excellent strength, thermal stability and weather resistance on the basis of lightweight. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a lightweight polyester tire and a preparation method thereof, which realizes lightweight while ensuring strength performance, thermal stability and weather resistance.

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows: A preparation method of a lightweight polyester tire, comprising the following steps: preparation of raw materials, spinning forming, tire base fabric forming, and post-setting treatment.

[0007] (1) Preparation of raw materials Maleic anhydride and water are mixed uniformly, then heated to 90-100℃, hydrolysis reaction for 1.8-2.2 hours, then heated to 130-135℃, dropwise addition of dicyclopentadiene, after dropwise addition is completed, reaction for 1.8-2.2 hours, then addition of octanediol and methanesulfonic acid, heating to 155-165℃, reaction for 1.2-1.5 hours, to obtain dicyclopentadiene modified ester; The mass ratio of maleic anhydride, water, dicyclopentadiene, octanediol and methanesulfonic acid is 100:85-90:85-95:120-130:0.1-0.12.

[0008] Maleic anhydride reacts with water to obtain maleic acid, and the maleic acid reacts with dicyclopentadiene at 130-135℃ to obtain a monoester of dicyclopentadiene maleic acid, which contains a carboxyl group, and the monoester undergoes esterification reaction with octanediol to obtain a dicyclopentadiene modified ester containing a hydroxyl group.

[0009] The phthalic acid, 2,6-naphthalene dicarboxylic acid and dicyclopentadiene modified ester are mixed, ethylene glycol, tetrabutyl titanate and triphenyl phosphite are added, and after being mixed uniformly, the temperature is raised to 210-220℃ under nitrogen atmosphere, the pressure is maintained at 0.3-0.5MPa, after 2-2.5 hours of reaction, the esterification is ended, the esterification product is raised to 230-240℃, and the polycondensation is carried out under normal pressure for 30-40min, then the temperature is raised to 255-265℃, and at the same time, vacuum is extracted to 30-50mbar; after 3-4h of reaction, small molecule substances are removed, the molecular chain is increased, and the polycondensation product is obtained, the polycondensation product is extruded and granulated by a double-screw extruder at a temperature of 270-280℃, and after cooling and drying, the functional polyester is obtained; The mass ratio of the phthalic acid, 2,6-naphthalene dicarboxylic acid, ethylene glycol, dicyclopentadiene modified ester, tetrabutyl titanate and triphenyl phosphite is 100:9-12:42-45:12-14:0.035-0.040:0.17-0.19; The phthalic acid is terephthalic acid; The temperature raising speed of the esterification product is 2-3℃ / min.

[0010] The dicyclopentadiene modified ester contains hydroxyl groups, the dicyclopentadiene modified ester, ethylene glycol and phthalic acid, 2,6-naphthalene dicarboxylic acid undergo esterification reaction, and after being raised in temperature, polycondensation is carried out, and finally obtained polyester is modified copolyester, the main chain of which is composed of terephthalic acid, ethylene glycol and 2,6-naphthalene dicarboxylic acid units, and the polyester contains polyester macromolecules with dicyclopentadiene maleic acid functional groups at one end or both ends of the molecular chain; at the same time, the dicyclopentadiene modified ester acts as an end-capping agent or copolymer segment, and participates in the reaction through the hydroxyl groups at the ends thereof, so that the norbornene structure is introduced into the copolyester molecular chain in the form of a side group or a chain end; The added triphenyl phosphite stabilizer can also inhibit the degradation of the dicyclopentadiene group to some extent.

[0011] (2) Spinning and forming In this step, the melt direct spinning hollow fiber process is adopted; the functional polyester obtained in step (1) is melted by screw extrusion under nitrogen protection, is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant-temperature nitrogen is introduced into the guide hole of the spinneret as the core medium for forming and maintaining the hollow structure of the fiber, the nitrogen pressure is stabilized in the range of 0.20-0.25MPa, and after multiple times of drafting, the hollow polyester filament is obtained; The melting temperature is 275-285℃; The hollow part area of the hollow polyester filament accounts for 30%-35% of the total cross-sectional area of the fiber; The fineness of the hollow polyester filament is 4.5-5.0dtex.

[0012] (3) Tire base fabric forming The hollow polyester filaments prepared in step (2) are opened and evenly spread by airflow to form a web, and the web weight is preliminarily controlled at 85-95 g / m 2 After needle consolidation, the web is immersed in a styrene-acrylic latex, and the web is pressed to have a liquid rate of 60-70%, pre-dried at 100-120 DEG C for 3-3.5 min, and baked at 145-155 DEG C for 2-2.5 min to ensure that the latex is uniformly penetrated and solidified, and a polyester tire is obtained. The latex solid content of the styrene-acrylic latex is 30-40 wt%, and the viscosity is 500-700 mPa·s. The needle density of the needle consolidation is 160-180 needles / cm 2 .

[0013] (4) Post-setting treatment The initial tire prepared in step (3) is placed at 150-160 DEG C for 20-30 min to further stabilize the dynamic crosslinking network structure and eliminate the processing internal stress.

[0014] Compared with the prior art, the present application has the following advantages: (1) The preparation method of the lightweight polyester tire of the present application uses functional polyester prepared by preparing a terpolymer of phthalic acid, 2,6-naphthalene dicarboxylic acid and dicyclopentadiene, so that the strength, thermal stability and weather resistance are ensured while the material is lightweighted by using hollow fibers. As a comonomer, 2,6-naphthalene dicarboxylic acid has a rigid naphthalene ring structure directly embedded in the polyester main chain, which significantly improves the thermal stability and modulus of the polymer, and its efficient ultraviolet absorption property absorbs and dissipates ultraviolet light energy at the source, directly protects the ester bond sensitive to light and reduces photo-oxidative cracking, and improves the weather resistance of the material. The norbornene double ring structure introduced by dicyclopentadiene serves as a rigid chain end, which enhances the steric hindrance and entanglement density between molecular chains, thereby inhibiting the thermal motion of chain segments and hindering the diffusion of oxygen and small molecule radicals, providing significant indirect weather resistance improvement, so that the material as a whole can better resist environmental stress, and has a higher mechanical property retention rate after aging.

[0015] (2) The preparation method of the lightweight polyester tire of the present application uses a melt direct spinning hollow fiber process, controls the hollow rate and fineness by stabilizing the nitrogen core layer medium, reduces the web weight, and realizes the lightweight requirement, and the breaking strength of the functional polyester fiber can reach 6.2-6.5 cN / dtex.

[0016] (3) The lightweight polyester tire prepared by the method has the advantages of light weight, strength performance and thermal stability, the weight of the tire base cloth is 103-115 g / m 2 , the transverse tensile force is 625-663 N / 50 mm, the transverse maximum tensile force elongation is 25.5-27.1%, the longitudinal tensile force is 637-684 N / 50 mm, the longitudinal maximum tensile force elongation is 24.3-26.1%, the thermal dimensional stability is 1.32-1.61%, the longitudinal tensile force retention rate after the weather resistance test is 68-72%, and the longitudinal maximum tensile force elongation retention rate is 63-66%. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application will be described.

[0018] Example 1 A lightweight polyester tire and a preparation method thereof, in particular: (1) Preparation of raw materials 10 g of maleic anhydride and 8.5 g of water are uniformly mixed, then heated to 90 DEG C, and hydrolysis reaction is carried out for 2.2 hours, then heated to 130 DEG C, 8.5 g of dicyclopentadiene is added dropwise, and reaction is carried out for 2.2 hours, then 12 g of octanediol and 0.01 g of methyl sulfonic acid are added, heated to 155 DEG C, and reaction is carried out for 1.5 hours to obtain dicyclopentadiene modified ester; 100 g of phthalic acid, 9 g of 2,6-naphthalene dicarboxylic acid and 12 g of dicyclopentadiene modified ester are mixed, 42 g of ethylene glycol, 0.035 g of tetrabutyl titanate and 0.17 g of triphenyl phosphite are added, uniformly mixed, then heated to 210 DEG C under nitrogen atmosphere, the pressure is maintained at 0.3 MPa, reaction is carried out for 2.5 hours, then esterification is completed, the esterification product is heated to 230 DEG C, and polycondensation is carried out under normal pressure for 40 min, then heated to 255 DEG C, and vacuum is extracted to 30 mbar; reaction is carried out for 4 h, small molecule substances are removed, molecular chain is increased, and a polycondensation product is obtained, the polycondensation product is extruded and granulated by a double screw extruder at a temperature of 270 DEG C, and the granules are cooled and dried to obtain a functional polyester; The heating speed of the esterification product is 2 DEG C / min.

[0019] (2) Spinning forming: the step adopts a melt direct spinning hollow fiber process; the functional polyester obtained in step (1) is extruded by a screw under nitrogen protection and at 275 DEG C, is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant-temperature nitrogen is introduced into a guide hole of a spinneret as a core medium for forming and maintaining the hollow structure of the fiber, the nitrogen pressure is 0.20 MPa, and after multiple times of drafting, a hollow polyester filament with a fineness of 4.5 dtex is obtained; The hollow portion of the hollow polyester filament accounts for 30% of the total cross-sectional area of the fiber; The breaking strength of the hollow polyester filament is 6.2 cN / dtex.

[0020] (3) Tire base fabric forming: the hollow polyester filaments prepared in step (2) are opened and evenly spread by airflow to form a web, and the web weight is preliminarily controlled at 85 g / m 2 After needle punching consolidation, the web is immersed in a styrene-acrylic latex, and the liquid rate is 60% after rolling. The web is pre-dried at 100℃ for 3.5 min and baked at 145℃ for 2.5 min to ensure uniform penetration and solidification of the latex, and a polyester tire is obtained. The latex solid content of the styrene-acrylic latex is 30 wt%, and the viscosity is 500 mPa·s. The needle punching density of the needle punching consolidation is 160 pokes / cm 2 .

[0021] (4) Post-forming treatment: the initial tire base fabric prepared in step (3) is placed at 150℃ for 30 min to further stabilize the dynamic crosslinking network structure and eliminate processing internal stress.

[0022] Example 2 A lightweight polyester tire and a preparation method thereof, specifically: (1) Preparation of raw materials 10 g of maleic anhydride and 8.8 g of water are mixed uniformly, then heated to 95℃, and hydrolysis reaction is carried out for 2 hours. Then, 8.8 g of dicyclopentadiene is added dropwise, and reaction is carried out for 2 hours. Then, 12.5 g of octanediol and 0.011 g of methyl sulfonic acid are added, and the temperature is raised to 160℃, and reaction is carried out for 1.3 hours to obtain a dicyclopentadiene modified ester. 100 g of phthalic acid, 10 g of 2,6-naphthalene dicarboxylic acid, and 13 g of dicyclopentadiene modified ester are mixed, 43 g of ethylene glycol, 0.038 g of tetrabutyl titanate, and 0.18 g of triphenyl phosphite are added, and the mixture is uniformly mixed. Then, the temperature is raised to 215℃ under nitrogen atmosphere, and the pressure is maintained at 0.4 MPa. After reaction for 2.2 hours, the esterification is completed. The esterification product is heated to 235℃, and polycondensation is carried out under normal pressure for 40 min. Then, the temperature is raised to 255℃, and vacuum is applied to 30 mbar. Reaction is carried out for 4 hours to remove small molecules and increase the molecular chain to obtain a polycondensation product. The polycondensation product is extruded and granulated by a twin-screw extruder at a temperature of 270℃. After cooling and drying, a functional polyester is obtained. The heating rate of the esterification product is 2.5℃ / min.

[0023] (2) Spinning and forming: This step adopts melt direct spinning hollow fiber process; the functional polyester obtained in step (1) is extruded by screw, melted under nitrogen protection at 280°C, and transported to hollow fiber spinning assembly by metering pump. Dry and constant temperature nitrogen is introduced into the spinneret guide hole as the core layer medium for forming and maintaining the hollow fiber structure. The nitrogen pressure is 0.22MPa. After multiple stretching, hollow polyester filament with a fineness of 5dtex is obtained. The hollow portion of the hollow polyester filament accounts for 32% of the total cross-sectional area of ​​the fiber. The tensile strength of the hollow polyester filament is 6.3 cN / dtex.

[0024] (3) Forming of the base fabric: After the hollow polyester filaments obtained in step (2) are opened, they are evenly spread by airflow to form a fiber web. The basis weight of the web is initially controlled at 90 g / m. 2 After needle-punching and solidification, it is immersed in styrene-acrylic latex, rolled to achieve a liquid content of 65%, pre-dried at 110℃ for 3.2 min, and baked at 150℃ for 2.2 min to ensure uniform penetration and curing of the latex, thus obtaining polyester tire. The styrene-acrylic latex has a latex solid content of 35 wt% and a viscosity of 600 mPa·s. The needle density of the acupuncture consolidation is 170 needles / cm². 2 .

[0025] (4) Post-forming treatment: The initial base prepared in step (3) is placed at 155℃ for 25 min to further stabilize the dynamic cross-linked network structure and eliminate processing internal stress.

[0026] Example 3 A lightweight polyester tire and its preparation method are as follows: (1) Preparation of raw materials After mixing 10g of maleic anhydride and 9g of water evenly, the mixture was first heated to 100℃ and hydrolyzed for 1.8 hours. Then, the mixture was heated to 135℃ and 9.5g of dicyclopentadiene was added dropwise. The mixture was reacted for 1.8 hours. Then, 13g of octanediol and 0.012g of methanesulfonic acid were added. The mixture was heated to 165℃ and reacted for 1.2 hours to obtain the dicyclopentadiene modified ester. 100g phthalic acid, 12g 2,6-naphthalene dicarboxylic acid and 14g dicyclopentadiene modified ester are mixed, 45g ethylene glycol, 0.038g tetrabutyl titanate and 0.19g triphenyl phosphite are added, after being mixed uniformly, the temperature is raised to 220℃ under nitrogen atmosphere, the pressure is maintained at 0.5MPa, after 2 hours of reaction, the esterification is ended, the esterification product is heated to 240℃, and is polycondensed under normal pressure for 30min, then the temperature is raised to 265℃, and vacuum is extracted to 50mbar; the reaction is carried out for 3h, small molecule substances are removed, the molecular chain is increased, and the polycondensation product is obtained; the polycondensation product is extruded and granulated by a double-screw extruder at a temperature of 280℃, and the granules are cooled and dried to obtain the functional polyester; The heating speed of the esterification product is 3℃ / min.

[0027] (2) Spinning forming: the functional polyester obtained in step (1) is extruded by a screw under nitrogen protection and at 285℃, is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant-temperature nitrogen is introduced into the guide hole of the spinneret as the core medium for forming and maintaining the hollow structure of the fiber, the nitrogen pressure is 0.20MPa, and after multiple drawing, the hollow polyester filament with a fineness of 4.5dtex is obtained; The hollow part area of the hollow polyester filament accounts for 30% of the total cross-sectional area of the fiber; The breaking strength of the hollow polyester filament is 6.5cN / dtex.

[0028] (3) Tire base fabric forming: the hollow polyester filament prepared in step (2) is opened and uniformly spread by airflow to form a fiber web, the basis weight of the web is preliminarily controlled at 95g / m 2 , is immersed in a styrene-acrylic latex after needle punching consolidation, is rolled to make the liquid rate 70%, is pre-dried at 120℃ for 3min, is baked at 155℃ for 2min, and the latex is uniformly penetrated and solidified to obtain a polyester tire; The latex solid content of the styrene-acrylic latex is 35wt%, and the viscosity is 700mPa·s; The needle punching density of the needle punching consolidation is 180picks / cm 2 .

[0029] (4) Post-setting treatment: the initial tire base fabric prepared in step (3) is placed at 160℃ for 20min to further stabilize the dynamic crosslinking network structure and eliminate processing internal stress.

[0030] Example 4 A lightweight polyester tire and a preparation method thereof, in particular: (1) Preparation of raw materials Mix 100 g of phthalic acid with 10 g of 2,6-naphthalene dicarboxylic acid, add 56 g of ethylene glycol, 0.038 g of tetrabutyl titanate and 0.18 g of triphenyl phosphite, mix uniformly, and then heat to 215℃ under a nitrogen atmosphere, with the pressure maintained at 0.4 MPa; after 2.2 hours of reaction, the esterification is completed, the esterification product is heated to 235℃, and is polycondensed under normal pressure for 40 min, and then heated to 255℃ while being vacuumed to 30 mbar; after 4 hours of reaction, small molecule substances are removed, and the molecular chain is lengthened to obtain a polycondensation product; the polycondensation product is extruded and granulated by a twin-screw extruder at a temperature of 270℃, and the granules are cooled and dried to obtain a functional polyester; The heating rate of the esterification product is 2.5℃ / min.

[0031] (2) Spinning forming: the functional polyester obtained in step (1) is extruded by a screw under nitrogen protection at 280℃, is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant-temperature nitrogen is introduced into the guide hole of the spinneret as a core medium for forming and maintaining the hollow structure of the fiber, the nitrogen pressure is 0.22 MPa, and after multiple drawing, a hollow polyester filament with a fineness of 5 dtex is obtained; The hollow part of the hollow polyester filament accounts for 32% of the total cross-sectional area of the fiber; The breaking strength of the hollow polyester filament is 5.7 cN / dtex.

[0032] (3) Tire base fabric forming: the hollow polyester filament prepared in step (2) is opened and uniformly spread by airflow to form a web, and the basis weight is preliminarily controlled at 90 g / m 2 After needle punching consolidation, the web is immersed in a styrene-acrylic latex, the liquid rate is 65% after rolling, the web is pre-dried at 110℃ for 3.2 min and baked at 150℃ for 2.2 min to ensure uniform penetration and solidification of the latex, and a polyester tire is obtained; The latex solid content of the styrene-acrylic latex is 35 wt%, and the viscosity is 600 mPa·s; to the polyester tire; The needle punching density of the needle punching consolidation is 170 pokes / cm 2 .

[0033] (4) Post-setting treatment: the initial tire base fabric prepared in step (3) is placed at 155℃ for 25 min to further stabilize the dynamic crosslinking network structure and eliminate processing internal stress.

[0034] Example 5 A lightweight polyester tire and a preparation method thereof, specifically: (1) Preparation of raw materials 10 g of maleic anhydride and 8.8 g of water were mixed uniformly, heated to 95℃, and hydrolysis was carried out for 2 hours. Then, 8.8 g of dicyclopentadiene was added dropwise, and reaction was carried out for 2 hours. Then, 12.5 g of octanediol and 0.011 g of methanesulfonic acid were added, heated to 160℃, and reaction was carried out for 1.3 hours to obtain dicyclopentadiene-modified ester; 110 g of phthalic acid and 13 g of dicyclopentadiene-modified ester were mixed, 43 g of ethylene glycol, 0.038 g of tetrabutyl titanate and 0.18 g of triphenyl phosphite were added, and after being mixed uniformly, the temperature was raised to 215℃ under nitrogen atmosphere, the pressure was maintained at 0.4 MPa, and reaction was carried out for 2.2 hours. After esterification was completed, the esterification product was heated to 235℃, and polycondensation was carried out under normal pressure for 40 min. Then, the temperature was raised to 255℃, and vacuum was applied to 30 mbar. Reaction was carried out for 4 hours to remove small molecules and increase the molecular chain to obtain polycondensation product. The polycondensation product was extruded and granulated by a double-screw extruder at 270℃, and after cooling and drying, functional polyester was obtained. The heating rate of the esterification product was 2.5℃ / min.

[0035] (2) Spinning forming: the functional polyester obtained in step (1) was melted by screw extrusion under nitrogen protection at 280℃, and was delivered to a hollow fiber spinning assembly by a metering pump. Dry and constant-temperature nitrogen was introduced into the guide hole of the spinneret as the core medium for forming and maintaining the hollow structure of the fiber, and the nitrogen pressure was 0.22 MPa. After multiple draw, hollow polyester filaments with a fineness of 5 dtex were obtained. The hollow part of the hollow polyester filaments accounted for 32% of the total cross-sectional area of the fiber. The breaking strength of the hollow polyester filaments was 5.1 cN / dtex.

[0036] (3) Tire base fabric forming: the hollow polyester filaments prepared in step (2) were opened and evenly spread by airflow to form a fiber web, and the basis weight was preliminarily controlled at 90 g / m 2 . After needle punching and consolidation, the tire base fabric was immersed in styrene-acrylic latex, and the liquid rate was 65% after rolling. After pre-drying at 110℃ for 3.2 min and baking at 150℃ for 2.2 min, it was ensured that the latex was uniformly penetrated and solidified to obtain a polyester tire. The solid content of the styrene-acrylic latex was 35 wt%, and the viscosity was 600 mPa·s. The needle punching density of the needle consolidation was 170 pokes / cm 2 .

[0037] (4) Post-setting treatment: the initial tire base fabric prepared in step (3) was placed at 155℃ for 25 min to further stabilize the dynamic crosslinking network structure and eliminate processing internal stress.

[0038] Example 6 A lightweight polyester tire and a preparation method thereof, in particular to: (1) Preparation of raw materials 10g of maleic anhydride and 8.8g of water were mixed uniformly, then heated to 95℃, and hydrolysis reaction was carried out for 2 hours, then heated to 132℃, and 8.8g of dicyclopentadiene was added dropwise, and reaction was carried out for 2 hours to obtain dicyclopentadiene modified ester; 100g of phthalic acid, 10g of 2,6-naphthalene dicarboxylic acid and 13g of dicyclopentadiene modified ester were mixed, 43g of ethylene glycol, 0.038g of tetrabutyl titanate and 0.18g of triphenyl phosphite were added, and after being mixed uniformly, it was heated to 215℃ under nitrogen atmosphere, the pressure was maintained at 0.4MPa, and after reaction for 2.2 hours, the esterification was completed, the esterification product was heated to 235℃, and the polycondensation was carried out under normal pressure for 40min, then heated to 255℃, and vacuumized to 30mbar at the same time; reaction for 4h, removal of small molecule substances, molecular chain growth, to obtain the polycondensation product, the polycondensation product was extruded and granulated by a double screw extruder at a temperature of 270℃, and the granules were cooled and dried to obtain the functional polyester; The heating speed of the esterification product is 2.5℃ / min.

[0039] (2) Spinning forming: the functional polyester obtained in step (1) is melted by screw extrusion under nitrogen protection at 280℃, and is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant temperature nitrogen gas is introduced into the guide hole of the spinneret as the core medium for forming and maintaining the hollow structure of the fiber, the nitrogen gas pressure is 0.22MPa, and after multiple drawing, the hollow polyester filament with a fineness of 5dtex is obtained; The hollow part area of the hollow polyester filament accounts for 32% of the total cross-sectional area of the fiber; The breaking strength of the hollow polyester filament is 6.3cN / dtex.

[0040] (3) Tire base fabric forming: the hollow polyester filament prepared in step (2) is opened and evenly spread by airflow to form a fiber web, and the basis weight is preliminarily controlled at 90g / m 2 After needle punching consolidation, it is immersed in styrene-acrylic latex, and the liquid rate is 65% after rolling and pressing, 110℃ pre-drying for 3.2min, 150℃ baking for 2.2min, to ensure uniform penetration and solidification of the latex, and obtain the polyester tire; The latex solid content of the styrene-acrylic latex is 35wt%, and the viscosity is 600mPa·s; The needle punching density of the needle punching consolidation is 170picks / cm 2 .

[0041] (4) Post-setting treatment: The initial tire base prepared in step (3) is placed at 155°C for 25 min to further stabilize the dynamic crosslinking network structure and eliminate internal stress.

[0042] Test Example 1 The grammage, tensile force, elongation at maximum tensile force, and thermal dimensional stability of the polyester tire bases prepared in Examples 1-6 above were tested according to the standard GB / T 18840-2018 "Tire Base for Asphalt Waterproofing Membrane", and the results are as follows:

[0043] The lightweight polyester tire bases prepared in Examples 1-3 had a grammage of 103-115 g / m 2 , a transverse tensile force of 625-663 N / 50 mm, an elongation at maximum transverse tensile force of 25.5-27.1%, a longitudinal tensile force of 637-684 N / 50 mm, an elongation at maximum longitudinal tensile force of 24.3-26.1%, and a thermal dimensional stability of 1.32-1.61%.

[0044] Example 4 was based on Example 2, but in the raw material preparation step, the preparation of the dicyclopentadiene-modified ester was omitted, and the same mass of ethylene glycol was used instead of the dicyclopentadiene-modified ester, and the remaining steps were the same. Example 5 was based on Example 2, but in the raw material preparation step, the addition of 2,6-naphthalene dicarboxylic acid was omitted, and the same mass of phthalic acid was used instead of 2,6-naphthalene dicarboxylic acid, and the remaining steps were the same. Example 6 was based on Example 2, but in the dicyclopentadiene-modified ester preparation step, the addition of octanediol was omitted, and the remaining steps were the same.

[0045] The tensile force of the polyester tire bases prepared in Examples 4 and 5 decreased significantly, verifying that the absence of dicyclopentadiene-modified ester and 2,6-naphthalene dicarboxylic acid can severely weaken the material strength. In particular, in Example 5, the dicyclopentadiene-modified ester alone cannot make up for the insufficient rigidity caused by the absence of 2,6-naphthalene dicarboxylic acid, and the strength is the lowest.

[0046] The elongation of Example 4 was the lowest, which was due to the absence of the toughening and end-capping effects of the dicyclopentadiene-modified ester: the norbornene structure introduced by dicyclopentadiene not only alleviates local stress concentration of the molecular chain through steric hindrance, but also reduces the brittle fracture sites of free chain ends through end-capping effect. Without this structure, the molecular chain is more prone to local brittle failure under stress, and the elongation performance is significantly inhibited.

[0047] The elongation of Example 5 was the highest among all examples, and the core reason was that the system lacked the rigid naphthalene ring support of 2,6-naphthalene dicarboxylic acid, and the molecular chain flexibility was significantly improved, making it more prone to slip deformation under external force, thus showing higher elongation properties.

[0048] The elongation of Example 6 is significantly lower than that of Example 2, which directly proves the importance of the octanediol flexible spacer. Without this spacer, the rigid dicyclopentadiene structure is directly connected, which can cause the local rigidity of the chain end to be too high, which is not conducive to the uniform dispersion of stress under macro stress, thereby reducing the overall toughness of the material.

[0049] Test Example 2 The polyester carcass prepared in Examples 1-6 above was subjected to weather resistance test, in which the power of the ultraviolet lamp was 40W, the wavelength was 365nm, the irradiation distance was 50cm, the temperature was 50℃, and after irradiation for 1000 hours, the longitudinal tensile force and the elongation at maximum longitudinal tensile force were detected, and the longitudinal tensile force retention rate and the elongation at maximum longitudinal tensile force retention rate were calculated, and the results are as follows.

[0050]

[0051] The lightweight polyester carcass prepared in Examples 1-3 has a longitudinal tensile force retention rate of 68-72% and an elongation at maximum longitudinal tensile force retention rate of 63-66% after the weather resistance test.

[0052] Example 4: longitudinal tensile force retention rate 65%, elongation retention rate 63%, although better than Example 4, but still lower than the double modified system, this group of samples contains naphthalene dicarboxylic acid, its naphthalene ring structure provides ultraviolet absorption capacity and main chain rigidity, so it still maintains moderate weather resistance. However, due to the complete lack of dicyclopentadiene modified ester, the molecular chain end lacks the rigid norbornene structure, and this dicyclic structure has high rigidity and steric hindrance effect, which can limit the movement ability of the molecular chain segment, reduce the chain segment relaxation and degradation induced by ultraviolet light or thermal oxidation; the lack of rigid norbornene structure will lead to insufficient entanglement density and overall structural stability between molecular chains. During the long-term aging process, the material has weak ability to resist stress deformation and inhibit the migration and diffusion of free radicals, so its performance retention rate is significantly lower than that of Examples 1-3 which contain both modified components. This reversely proves that the structure modified by dicyclopentadiene can delay the aging process by enhancing the interchain interaction.

[0053] Example 5: The longitudinal tensile strength retention rate is only 59%, and the elongation retention rate is 56%. Although the dicyclopentadiene structure is introduced, it can limit the chain segment movement to a certain extent and improve the thermal stability through its rigid bridge ring, but due to the complete lack of naphthalene dicarboxylic acid, the material loses the direct ultraviolet shielding barrier and the main chain rigid support. Ultraviolet light can penetrate directly and directly cause the ester bond photooxidation of the polyester main chain to break. In this case, the indirect reinforcing effect of dicyclopentadiene cannot make up for the fundamental shortcoming of the material in direct defense, resulting in a serious decline in mechanical properties after aging. This result strongly confirms the core role of naphthalene dicarboxylic acid in the copolymer system, and highlights the technical necessity of the cooperation of naphthalene dicarboxylic acid and dicyclopentadiene in the present application.

[0054] Example 6: The longitudinal tensile strength retention rate and the elongation retention rate are slightly lower than the corresponding data of Example 2. When the synthesis of dicyclopentadiene modified ester is omitted, the rigid dicyclopentadiene structure may be connected to the end of the polyester molecular chain with a shorter and more direct chemical bond. This structure makes the rigidity and steric hindrance effect of the chain end part more concentrated, but at the same time, it also loses the flexibility buffer and stress dispersion effect provided by the long carbon chain of octanediol. The coordination ability of local molecular chain movement and the micro-zone stress dissipation ability of the material are affected during the long-term aging process, which finally shows a slight decrease in the retention rate of mechanical properties.

[0055] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a lightweight polyester carcass, characterized by, It comprises the following steps: Preparation of raw materials, spinning, tire base forming, post-setting treatment; The preparation method of the raw material is as follows: after maleic anhydride and water are uniformly mixed, the mixture is first heated to 90-100℃, and hydrolysis reaction is carried out for 1.8-2.2 hours, then the temperature is raised to 130-135℃, dicyclopentadiene is added dropwise, after the dropwise addition is completed, reaction is carried out for 1.8-2.2 hours, then octanediol and methanesulfonic acid are added, the temperature is raised to 155-165℃, and reaction is carried out for 1.2-1.5 hours to obtain dicyclopentadiene-modified ester; Phthalic acid and 2,6-naphthalene dicarboxylic acid are mixed with the dicyclopentadiene-modified ester, ethylene glycol, tetrabutyl titanate and triphenyl phosphite are added, and after being uniformly mixed, the mixture is heated to 210-220℃ under nitrogen atmosphere, the pressure is maintained at 0.3-0.5MPa, and after reaction for 2-2.5 hours, the esterification is completed, the esterification product is heated to 230-240℃, and polycondensation is carried out under normal pressure for 30-40min, then the temperature is raised to 255-265℃, and at the same time, vacuum is applied to 30-50mbar, reaction is carried out for 3-4h to remove small molecular substances and increase the molecular chain, and the polycondensation product is obtained, which is extruded and granulated by a double-screw extruder at a temperature of 270-280℃, and after cooling and drying, the functional polyester is obtained.

2. The lightweight polyester carcass according to claim 1, wherein, The mass ratio of the maleic anhydride, water, dicyclopentadiene, octanediol and methanesulfonic acid is 100:85-90:85-95:120-130:0.1-0.

12.

3. The lightweight polyester carcass according to claim 1, wherein, The mass ratio of the phthalic acid, 2,6-naphthalene dicarboxylic acid, ethylene glycol, dicyclopentadiene-modified ester, tetrabutyl titanate and triphenyl phosphite is 100:9-12:42-45:12-14:0.035-0.040:0.17-0.

19.

4. The lightweight polyester carcass according to claim 1, wherein, The method for spinning is as follows: the functional polyester obtained in the preparation step of the raw material is extruded by a screw under nitrogen protection, is delivered to a hollow fiber spinning assembly by a metering pump, dry and constant-temperature nitrogen is introduced into the guide hole of the spinneret as the core medium for forming and maintaining the hollow structure of the fiber, the nitrogen pressure is stabilized in the range of 0.20-0.25MPa, and after multiple times of drawing, the hollow polyester filament is obtained.

5. The lightweight polyester carcass according to claim 4, wherein, The hollow part of the hollow polyester filament accounts for 30%-35% of the total cross-sectional area of the fiber; and the fineness of the hollow polyester filament is 4.5-5.0dtex.

6. The lightweight polyester carcass according to claim 1, wherein, The method for forming the tire base fabric is to spread the hollow polyester filaments prepared in the spinning forming step uniformly by airflow after opening to form a web, and to preliminarily control the web weight at 85-95 g / m 2 After needle punching and consolidation, the web is immersed in a styrene-acrylic latex, and is pressed to have a liquid content of 60-70%, and is pre-dried at 100-120°C for 3-3.5 min, and is baked at 145-155°C for 2-2.5 min to obtain a polyester tire base fabric.

7. The lightweight polyester carcass according to claim 6, wherein, The phenylpropyl latex has a latex solid content of 30-40 wt%, and a viscosity of 500-700 mPa·s; the needle punching density of the needle punching consolidation is 160-180 needles / cm 2 .

8. The lightweight polyester carcass according to claim 1, wherein, The method for post-setting treatment is as follows: the initial tire base prepared in the tire base forming step is placed in an oven at 150-160℃ for 20-30min.

9. A lightweight polyester tire prepared by any one of the methods of claims 1-8.

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