Polyurethane elastomer special for elasticizer friction disc and synthesis process

Abstract

The invention discloses a special polyurethane elastomer for a friction disc of an elasticizer and a synthesis process. The preparation method comprises the following steps: dissolving TODI in a mixed solvent, adding dehydrated hydroxyl-terminated polycarbonate diol and phosphoric acid, and reacting to obtain a prepolymer solution; removing the solvent in the prepolymer solution to obtain a prepolymer solution with medium viscosity; mixing the prepolymer semi-solution with a chain extender 1 at a specific temperature, and fully reacting to obtain a polyurethane elastomer semi-solution; adding the polyurethane elastomer semi-solution into a twin-screw extruder, removing a solvent in the polyurethane elastomer semi-solution by using a small-lead reverse thread element, a 90-degree kneading block and a vacuum port, and adding a composite lubricant, a composite antioxidant and a composite light stabilizer for granulation, so as to obtain the polyurethane elastomer composite material. The special thermoplastic polyurethane elastomer for the friction disc of the elasticizer is obtained. By means of the process, more excellent performance consistency, stability, abrasion resistance, damp heat resistance and oil resistance can be obtained, and therefore the longer service life is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and relates to a thermoplastic polyurethane elastomer and a synthesis process for a friction disc of a texturizing machine. The material of the present invention can meet the domestic high-end requirements of the friction disc of the texturizing machine, and surpass the high-performance products of Germany or Japan in terms of performance stability, wear resistance, yellowing, life and other performances, thus truly realizing domestic high-end requirements. Background Art

[0002] The texturing machine, also known as the false twist stretch yarn machine, is a textile machine that can process untwisted raw yarns such as POY yarn (polyester yarn) into DTY stretch yarns with good fluffiness, high elasticity and different elastic requirements through heating, stretching and false twisting.

[0003] The polyurethane friction disc is a core part of the texturing machine. Its function is to make the chemical fiber virgin yarn elastic, fluffy and have a good feel through false twist deformation (twisting first, then shaping and untwisting). Since the polyurethane friction disc false-twists the chemical fiber virgin yarn through high-speed rotation, it has extremely high requirements on the performance of the polyurethane elastomer on the working arc surface, including consistency, stability, wear resistance, oil resistance, moisture and heat resistance, etc. Up to now, the mainstream friction disc polyurethane elastic material system is polycarbonate diol + 1,4-butanediol + 3,3'-dimethyl-4,4'-biphenyl diisocyanate (TODI). However, there are still technical difficulties in the preparation of the above materials in China, mainly the following three points:

[0004] (1) Polycarbonate diol is the most suitable main material for this application due to its structural characteristics and performance advantages. However, due to its very high viscosity, polycarbonate diol brings great difficulties to the development and production of synthesis technology.

[0005] (2) Since the friction disc has extremely high requirements for polyurethane elastomers, the regularity of the molecular chain structure of the polyurethane material must be strictly controlled during the synthesis process. In order to obtain a highly regular structure, it is necessary to use the prepolymer method for synthesis. However, the polycarbonate-based prepolymer synthesized by the conventional method has a higher viscosity and cannot be stably cast using a casting machine.

[0006] (3) Even if an enterprise or R&D institution is able to synthesize the polycarbonate diol + 1,4-butanediol + TODI system through a special method (currently not reported), the overall performance is at most on par with the German friction disc, and still cannot be surpassed. Summary of the invention

[0007] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide a thermoplastic polyurethane elastomer and a synthesis process for a friction disc of a texturizing machine. The polyurethane elastomer and the process can achieve more excellent performance consistency, stability, wear resistance, moisture and heat resistance, and oil resistance, thereby achieving a longer service life.

[0008] The technical solution of the present invention:

[0009] A polyurethane elastomer specially used for friction discs of texturizing machines is prepared from the following components measured in parts by mass:

[0010]

[0011] The PCD is a hydroxy-terminated polycarbonate diol with a number average molecular weight (Mn) of 1000-3000 and a functionality of 2.0, preferably 1000-2000.

[0012] The chain extender 1 is hydroquinone dihydroxyethyl ether HQEE, with a purity of ≥99%.

[0013] The chain extender 2 is 1,4-BDO, which is 1,4-butanediol, and has a purity of ≥99%.

[0014] The TODI is 3,3'-dimethyl-4,4'-biphenyl diisocyanate, and the purity is ≥98%.

[0015] The lubricant is a composite lubricant, including two or more of oleamide, erucamide, ethylene bisstearamide, polyethylene wax and montan wax.

[0016] The antioxidant is a composite antioxidant, including two or more of antioxidant 1010, antioxidant 245, antioxidant 168, antioxidant 1135, and antioxidant 1035.

[0017] The light stabilizer is a composite light stabilizer, including two or more of UV-328, UV-765, UV-770 and UV-622.

[0018] A synthesis process of a polyurethane elastomer specially used for friction discs of texturizing machines, characterized by the following steps:

[0019] Step 1: dissolving TODI in a mixed solvent, and then adding dehydrated hydroxyl-terminated polycarbonate diol and phosphoric acid to react to obtain a prepolymer solution;

[0020] Step 2: removing the solvent in the prepolymer solution using a vacuum device until the solvent reaches a suitable viscosity, thereby obtaining a prepolymer solution of medium viscosity (hereinafter referred to as a prepolymer semi-solution);

[0021] Step 3: at a specific temperature, mixing the prepolymer semi-solution with the chain extender 1 to fully react to obtain a polyurethane elastomer semi-solution;

[0022] Step 4: adding the polyurethane elastomer semi-solution into a twin-screw extruder, removing the solvent from the polyurethane elastomer semi-solution by using a small-pitch reverse screw element, a 90° kneading block and a vacuum port, and adding a composite lubricant, a composite antioxidant and a composite light stabilizer for granulation;

[0023] Step 5: Dry the granulated particles to obtain a thermoplastic polyurethane elastomer specially used for friction discs of texturizing machines.

[0024] In step 1, the mixed solvent is a solvent that makes the reaction system inert, specifically a combination of two or more of aromatic compounds, monoesters, diesters, carbonates, amides, and heterocyclics, preferably diesters and aromatic compounds. At 23°C, the solubility of TODI in the mixed solvent is 5% to 50%, and the boiling point of the mixed solvent is 50°C to 150°C, preferably 50°C to 100°C. The weight ratio of the mixed solvent to TODI is 1:1 to 10:1, preferably 2:1 to 5:1.

[0025] In step 1, the reaction temperature is 60 to 80° C. and the reaction time is 2 to 4 hours.

[0026] In step 1, the hydroxy-terminated polycarbonate diol is added in batches of 1 to 5 times or continuously dropped, preferably in batches of 3 to 4 times, and more preferably, continuously dropped.

[0027] In step 2, the temperature of the prepolymer solution is 100 to 120° C., the vacuum degree is -0.08 MPa to -0.1 MPa, and the weight of the removed solvent is 50% to 80% of the total weight of the solvent.

[0028] In step 3, the reaction temperature is 80-130° C., and the reaction time is 1-2 hours.

[0029] In step 3, a chain extender 2 is also added.

[0030] In step 4, the twin-screw extruder refers to a screw with a length-to-diameter ratio of 40:1 to 60:1, the screw is divided into three sections, has three vacuum ports, and a small-lead reverse screw element and a 90° kneading block are provided in front of the vacuum ports.

[0031] In step 4, the temperature setting of the twin-screw extruder is divided into three sections, the first section is 150°C to 180°C, the second section is 120°C to 150°C, and the third section is 80°C to 130°C.

[0032] The mechanism of the present invention is:

[0033] (1) Select a mixed solvent with high solubility of TODI and inert to the reaction involved to fully dissolve TODI, and add the hydroxy-terminated polycarbonate diol in batches of 3 to 4 times or continuously dropwise in the homogeneous phase to ensure a mild reaction process and a uniform distribution of the degree of polymerization.

[0034] (2) In order to avoid interference of excessive solvent on the chain extension reaction and to facilitate the subsequent removal of the solvent, a portion of the solvent is first removed in step 2.

[0035] (3) Chain extension reaction is carried out in the prepolymer semi-solution. The material viscosity is extremely low, the exothermic reaction is mild, the molecular weight distribution is narrow, and the molecular weight size is controllable. (The performance and life of polymer materials are closely related to the molecular weight distribution and molecular weight size of the material).

[0036] (4) Since the screw elements of the twin-screw extruder screw are all free spline combinations, the screw structure can be easily customized. The screw in the present invention is provided with three vacuum ports, and a small lead reverse screw element and a 90° kneading block are provided in front of the three vacuum ports. This arrangement can make the melt very slow when passing through the vacuum port, thereby performing high vacuum degree solvent removal.

[0037] (5) The three-stage heating of the twin-screw extruder can prevent thermal degradation of the material in the screw and control the solvent removal rate to avoid excessive solvent removal, which would increase the difficulty of subsequent solvent recovery.

[0038] Beneficial effects of the present invention:

[0039] (1) The thermoplastic polyurethane elastomer for friction discs of texturizing machines of the present invention uses HQEE with a high benzene ring content to partially or completely replace aliphatic 1,4-butanediol, so its dynamic wear resistance, moisture and heat resistance, and oil resistance are greatly improved, which is the theoretical basis recognized by the industry. However, since HQEE does not have the phenomenon of supercooling, the control of the production process is particularly fine and requires extremely high requirements, which is also well known to technicians in the industry. Conventional technology uses polycarbonate diol to synthesize prepolymers, and then uses a casting machine for chain extension casting. However, since the viscosity of polycarbonate diol itself is very high, the viscosity after the synthesis of prepolymers will become even higher. This high-viscosity material cannot be accurately measured and stably pressure-delivered by the metering pump of the casting machine, nor can it be fully mixed by the mixing head of the casting machine, and the pressure of the entire casting machine system will become particularly high. The above reasons will lead to the inability to accurately proportion the materials of the system, and its performance cannot be guaranteed. The present invention provides a new synthesis process, which can not only solve the problem that the high viscosity in the process of synthesizing prepolymer of polycarbonate diol leads to the inability to use a casting machine for stable bulk polymerization production, but also can easily solve the use and reaction control problems of HQEE.

[0040] (2) The thermoplastic polyurethane elastomer process for texturizing machine friction discs of the present invention can easily realize the addition of more powder additives, such as composite antioxidants and composite light stabilizers. In conventional synthesis technology, powder additives can only be added to prepolymers, but it is well known that the addition of some powders will thicken the liquid, which will cause the viscosity of the polycarbonate-based prepolymer, which is already very high, to become even higher, making it impossible to proceed to the next step. However, the present invention can open a powder feeding port at any position on the twin-screw barrel, and can easily realize the addition of a large proportion of powder additives using simple metering feeding equipment.

[0041] (3) The present invention provides a new synthesis route for the synthesis process of polycarbonate-based polyurethane elastomers, which not only solves the problem of polycarbonate diol in the process of synthesizing TPU, but also solves the problem that other high-viscosity raw materials are difficult or impossible to use, and provides a new technical means for the future development of special polyurethane elastomer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the structure of a twin-screw extruder.

[0043] Figure 2 This is a graph showing the results of the polyurethane elastomer obtained in Example 1.

[0044] Figure 3 This is a diagram of the polyurethane elastomer results obtained in Example 2.

[0045] Figure 4 This is a graph showing the results of the polyurethane elastomer obtained in Example 3.

[0046] Figure 5 This is a graph showing the results of the polyurethane elastomer obtained in Example 4.

[0047] Figure 6 This is a graph showing the result of the polyurethane elastomer obtained in Comparative Example 1.

[0048] Figure 7 This is a graph showing the result of the polyurethane elastomer obtained in Comparative Example 3. DETAILED DESCRIPTION

[0049] The specific implementation of the present invention is further described below in conjunction with the technical solution.

[0050] Embodiment 1:

[0051] A synthesis process of a polyurethane elastomer specially used for friction discs of texturizing machines, the steps are as follows:

[0052] (1) 5 kg of ethyl acetate and 1 kg of xylene were fully mixed in a kettle, and 1.23 kg of TODI powder was added after mixing, and the temperature was controlled to 40°C. After complete dissolution, 0.1 g of phosphoric acid was added dropwise for later use. The dehydrated polycarbonate diol with a molecular weight of Mn = 2000 was controlled to 70°C, a total of 4 kg, and was added to the kettle in 3 equal portions, each time with an interval of 20 minutes. After all additions were completed, the temperature was controlled to 70±5°C for reaction for 2 hours, and the NCO% content was measured to reach the designed value to obtain a prepolymer solution.

[0053] (2) The prepolymer solution was heated to 90° C. and the solvent was distilled at a vacuum of -0.08 MPa to distill out about 3 kg of solvent to obtain a prepolymer semi-solution.

[0054] (3) The prepolymer semi-solution was temperature controlled to 90° C., 0.48 kg of HQEE flake solid was added, the mixture was fully stirred, and the reaction was carried out for 1 hour to obtain a polyurethane elastomer semi-solution.

[0055] (4) The semi-solution of polyurethane elastomer was added to a twin-screw extruder. The first section was 180° C., the second section was 150° C., and the third section was 120° C. The solvent was removed in the configuration of a small-lead reverse screw element, a 90° kneading block, and a vacuum port (vacuum degree -0.05 to -0.08 MPa). 6 g of oleamide, 6 g of erucamide, 9 g of antioxidant 1010, 6 g of antioxidant 168, 9 g of UV-770, and 6 g of UV-622 were added and granulation was carried out.

[0056] (5) The granules are dried to obtain the thermoplastic polyurethane elastomer of the present invention.

[0057] Embodiment 2:

[0058] A synthesis process of a polyurethane elastomer specially used for friction discs of texturizing machines, the steps are as follows:

[0059] (1) 5 kg of tetrahydrofuran and 1 kg of dimethyl carbonate were fully mixed in a kettle, and then 1.23 kg of TODI powder was added after mixing, and the temperature was controlled to 40°C. After complete dissolution, 0.1 g of phosphoric acid was added dropwise for later use. The dehydrated polycarbonate diol with a molecular weight of Mn = 2000 was controlled to 70°C, a total of 4 kg, and was added to the kettle in 3 equal portions, each time with an interval of 20 minutes. After all additions were completed, the temperature was controlled to 70±5°C for reaction for 2 hours, and the NCO% content was measured to reach the designed value to obtain a prepolymer solution.

[0060] (2) The prepolymer solution was heated to 90° C. and the solvent was distilled at a vacuum of -0.08 MPa to distill out about 3 kg of solvent to obtain a prepolymer semi-solution.

[0061] (3) The prepolymer semi-solution was temperature controlled to 90° C., 0.48 kg of HQEE flake solid was added, the mixture was fully stirred, and the reaction was carried out for 1 hour to obtain a polyurethane elastomer semi-solution.

[0062] (4) The semi-solution of polyurethane elastomer was added to a twin-screw extruder. The first section was 180° C., the second section was 150° C., and the third section was 120° C. The solvent was removed in the configuration of a small-lead reverse screw element, a 90° kneading block, and a vacuum port (vacuum degree -0.05 to -0.08 MPa). 6 g of oleamide, 6 g of erucamide, 9 g of antioxidant 1010, 6 g of antioxidant 168, 9 g of UV-770, and 6 g of UV-622 were added and granulation was carried out.

[0063] (5) The granules are dried to obtain the thermoplastic polyurethane elastomer of the present invention.

[0064] Embodiment 3:

[0065] A synthesis process of a polyurethane elastomer specially used for friction discs of texturizing machines, the steps are as follows:

[0066] (1) 5 kg of ethyl acetate and 1 kg of xylene were fully mixed in a kettle, and 1.23 kg of TODI powder was added after mixing, and the temperature was controlled to 40°C. After complete dissolution, 0.1 g of phosphoric acid was added dropwise for later use. The dehydrated polycarbonate diol with a molecular weight of Mn = 2000 was controlled to 70°C, a total of 4 kg, and was added to the kettle in 3 equal portions, each time with an interval of 20 minutes. After all additions were completed, the temperature was controlled to 70±5°C for reaction for 2 hours, and the NCO% content was measured to reach the designed value to obtain a prepolymer solution.

[0067] (2) The prepolymer solution was heated to 90° C. and the solvent was distilled at a vacuum of -0.08 MPa to distill out about 3 kg of solvent to obtain a prepolymer semi-solution.

[0068] (3) The prepolymer semi-solution was temperature-controlled to 90° C., 0.391 kg of HQEE flake solid and 0.039 kg of 1,4-butanediol were added, the mixture was stirred thoroughly, and the mixture was reacted for 1 hour to obtain a polyurethane elastomer semi-solution.

[0069] (4) The semi-solution of polyurethane elastomer was added to a twin-screw extruder. The first section was 180° C., the second section was 150° C., and the third section was 120° C. The solvent was removed in the configuration of a small-lead reverse screw element, a 90° kneading block, and a vacuum port (vacuum degree -0.05 to -0.08 MPa). 6 g of oleamide, 6 g of erucamide, 9 g of antioxidant 1010, 6 g of antioxidant 168, 9 g of UV-770, and 6 g of UV-622 were added and granulation was carried out.

[0070] (5) The granules are dried to obtain the thermoplastic polyurethane elastomer of the present invention.

[0071] Embodiment 4:

[0072] A synthesis process of a polyurethane elastomer specially used for friction discs of texturizing machines, the steps are as follows:

[0073] (1) 5 kg of ethyl acetate and 1 kg of xylene were fully mixed in a kettle, and then 1.467 kg of TODI powder was added after mixing, and the temperature was controlled to 40°C. After complete dissolution, 0.1 g of phosphoric acid was added dropwise for later use. The dehydrated polycarbonate diol with a molecular weight of Mn = 1000 was controlled to 70°C, a total of 4 kg, and was added to the kettle in 3 equal portions, each time with an interval of 20 minutes. After all additions were completed, the temperature was controlled to 70±5°C for reaction for 2 hours, and the NCO% content was measured to reach the designed value to obtain a prepolymer solution.

[0074] (2) The prepolymer solution was heated to 90° C. and the solvent was distilled at a vacuum of -0.08 MPa to distill out about 3 kg of solvent to obtain a prepolymer semi-solution.

[0075] (3) The prepolymer semi-solution was temperature controlled to 90° C., 0.48 kg of HQEE flake solid was added, the mixture was fully stirred, and the reaction was carried out for 1 hour to obtain a polyurethane elastomer semi-solution.

[0076] (4) The semi-solution of polyurethane elastomer was added to a twin-screw extruder. The first section was 180° C., the second section was 150° C., and the third section was 120° C. The solvent was removed in the configuration of a small-lead reverse screw element, a 90° kneading block, and a vacuum port (vacuum degree -0.05 to -0.08 MPa). 6 g of oleamide, 6 g of erucamide, 9 g of antioxidant 1010, 6 g of antioxidant 168, 9 g of UV-770, and 6 g of UV-622 were added and granulation was carried out.

[0077] (5) The granules are dried to obtain the thermoplastic polyurethane elastomer of the present invention.

[0078] Comparative Example 1: Conventional Manual Synthesis

[0079] (1) Take 4 kg of dehydrated polycarbonate diol with a molecular weight of Mn=2000 and control the temperature to 70°C, add 1.475 kg of TODI powder at one time, control the temperature to 70-80°C, react for 3 hours, measure the NCO% content to reach the designed value, and obtain a prepolymer. Add 6 g of oleamide, 6 g of erucamide, 9 g of antioxidant 1010, 6 g of antioxidant 168, 9 g of UV-770, and 6 g of UV-622, stir evenly and set aside.

[0080] (2) Control the temperature of 1,4-butanediol to 40°C, weigh 0.293 kg, add it to the 90°C prepolymer, and stir it manually. After mixing, pour the material into a 160°C tray and keep it warm for 2 hours.

[0081] (3) The insulated material was transferred to a 110°C oven and kept warm for 20 hours.

[0082] (4) The bulk synthetic material is crushed into small particles and dried to obtain the product.

[0083] Comparative Example 2:

[0084] Based on Example 1, 5 KG of ethyl acetate and 1 KG of xylene in step (1) were replaced with 5 KG of dimethyl phthalate and 1 KG of dibutyl adipate.

[0085] Comparative Example 3:

[0086] Based on Example 1, the specific structure in step (4) is replaced with a common positive thread element.

[0087] Comparative Example 4:

[0088] Based on Example 1, step (2) is cancelled and step (4) is directly performed.

[0089] The processing technology test was performed on the thermoplastic polyurethane elastomers prepared in Examples 1 to 4 and Comparative Examples 1 to 4:

[0090] Example 1: The injection molding is smooth; the melting range is wide, 195°C to 205°C; the molding speed is fast, the whole process is 45 seconds; the product has no obvious shrinkage.

[0091] Example 2: Injection molding is smooth; the melting range is wide, 195°C to 205°C; the molding speed is fast, the whole process is 45 seconds; the product has no obvious shrinkage.

[0092] Example 3: Injection molding is smooth; the melting range is wide, 190°C to 200°C; the molding speed is slow, the whole process is 60 seconds; the product has slight shrinkage.

[0093] Example 4: Injection molding is smooth; the melting range is wide, 185°C to 195°C; the molding speed is slow, the whole process is 60 seconds, and the product shrinks slightly.

[0094] Comparative Example 1: Injection molding is smooth; the melting range is narrow, 185°C to 190°C; the molding speed is extremely slow, the whole process is 80 seconds, and the product has obvious shrinkage.

[0095] Comparative Example 2: The obtained particles are honeycomb-shaped and cannot be normally injection molded. The product contains a lot of solvents. The injection molded product contains a lot of bubbles and shrinks severely.

[0096] Comparative Example 3: The obtained particles are honeycomb-shaped and can be injection molded, but the product contains solvents, the injection molding process has a heavy solvent odor, and the product contains tiny bubbles and cannot be used or tested.

[0097] Comparative Example 4: Due to the large amount of solvent, the material entering the extruder screw produces a large amount of evaporating gas and the operation cannot be continued.

[0098] Summary: Considering the processing technology:

[0099] Comparative Example 1 has great difficulty in injection molding debugging, slow molding speed, and obvious shrinkage of the product, which is not suitable for industrial production.

[0100] In Comparative Example 2, since the selected solvent has a high boiling point, it cannot be completely removed, resulting in a large number of honeycomb pores in the granular product, and injection molding cannot be completed.

[0101] In Comparative Example 3, since a small-pitch reverse thread and a 90° kneading block are not provided, the melt travels too fast in the screw and the residence time is too short. Although most of the solvent can be removed, it cannot be completely removed, resulting in a small amount of solvent vaporization during injection molding. Numerous tiny bubbles are formed in the injection molded product, which cannot be used or tested.

[0102] Comparative Example 4 was unable to obtain a granular product, and even more unable to perform injection molding.

[0103] Similar problems exist in Example 3 and Example 4. The product needs a long cooling time to complete shaping. Slight shrinkage can meet the appearance requirements by optimizing the mold design.

[0104] The processing technology of Example 1 and Example 2 is good and is very suitable for injection molding batch production.

[0105] The performance of the thermoplastic polyurethane elastomers prepared in Examples 1 to 4 and Comparative Example 1 was tested. The results are shown in Table 1.

[0106] Table 1 Performance indicators of thermally cross-linked thermoplastic polyurethane elastomer

[0107]

[0108] Note: Tensile test conditions: 23℃, tensile speed 200mm / min; Compression set test conditions: 25% compression at 100℃, 24 hours hot air aging; Medium resistance test conditions: 46# hydraulic oil aging at 120℃ for 7 days.

[0109] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A polyurethane elastomer specially used for friction discs of texturizing machines, characterized in that: The polyurethane elastomer specially used for friction disc of texturizing machine is prepared from the following components measured in parts by mass:

2. The polyurethane elastomer for friction disc of texturizing machine according to claim 1, characterized in that: The PCD is a hydroxyl-terminated polycarbonate diol with a number average molecular weight of 1000 to 3000 and a functionality of 2.0; The chain extender 1 is hydroquinone dihydroxyethyl ether HQEE; The chain extender 2 is 1,4-BDO which is 1,4-butanediol; The TODI is 3,3'-dimethyl-4,4'-biphenyl diisocyanate; The lubricant is a composite lubricant, including two or more of oleamide, erucamide, ethylene bisstearamide, polyethylene wax, and montan wax; The antioxidant is a composite antioxidant, including two or more of antioxidant 1010, antioxidant 245, antioxidant 168, antioxidant 1135, and antioxidant 1035; The light stabilizer is a composite light stabilizer, including two or more of UV-328, UV-765, UV-770 and UV-622.

3. A synthesis process of a polyurethane elastomer for a friction disc of a texturizing machine, characterized in that: step: Step 1: dissolving TODI in a mixed solvent, and then adding dehydrated hydroxyl-terminated polycarbonate diol and phosphoric acid to react to obtain a prepolymer solution; Step 2: removing the solvent in the prepolymer solution using a vacuum device until the solvent reaches a suitable viscosity, thereby obtaining a prepolymer solution of medium viscosity (hereinafter referred to as a prepolymer semi-solution); Step 3: at a specific temperature, mixing the prepolymer semi-solution with the chain extender 1 to fully react to obtain a polyurethane elastomer semi-solution; Step 4: adding the polyurethane elastomer semi-solution into a twin-screw extruder, removing the solvent from the polyurethane elastomer semi-solution by using a small-pitch reverse screw element, a 90° kneading block and a vacuum port, and adding a composite lubricant, a composite antioxidant and a composite light stabilizer for granulation; Step 5: Dry the granulated particles to obtain a thermoplastic polyurethane elastomer specially used for friction discs of texturizing machines.

4. The synthesis process according to claim 3, characterized in that: In step 1, the mixed solvent is a solvent that makes the reaction system inert, specifically a combination of two or more of aromatic compounds, monoesters, diesters, carbonates, amides, and heterocyclics; at 23° C., the solubility of TODI in the mixed solvent is 5% to 50%, and the boiling point of the mixed solvent is 50° C. to 150° C.; the weight ratio of the mixed solvent to TODI is 1:1 to 10:

1.

5. The synthesis process according to claim 3, characterized in that: In step 1, the reaction temperature is 60 to 80° C., and the reaction time is 2 to 4 hours.

6. The synthesis process according to claim 3, characterized in that: In step 1, the hydroxy-terminated polycarbonate diol is added in batches of 1 to 5 times or added dropwise continuously.

7. The synthesis process according to claim 3, characterized in that: In step 2, the temperature of the prepolymer solution is 100 to 120° C., the vacuum degree is -0.08 MPa to -0.1 MPa, and the weight of the removed solvent is 50% to 80% of the total weight of the solvent.

8. The synthesis process according to claim 3, characterized in that: In step 3, the specific temperature is 80 to 130° C., and the reaction time at the specific temperature is 1 to 2 hours.

9. The synthesis process according to claim 3, characterized in that: In step 3, a chain extender 2 is also added.

10. The synthesis process according to claim 3, characterized in that: In step 4, the twin-screw extruder refers to a screw with a length-to-diameter ratio of 40:1 to 60:1, the screw is divided into three sections, has three vacuum ports, and a small-lead reverse screw element and a 90° kneading block are provided in front of the vacuum ports; the temperature setting of the twin-screw extruder is divided into three sections, the first section is 150°C to 180°C, the second section is 120°C to 150°C, and the third section is 80°C to 130°C.

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