High-temperature-resistant and wear-resistant modified TPU film and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant and wear-resistant modified TPU film and a preparation method thereof.The preparation method comprises the steps that S1, a long-chain silane coupling agent, ethyl alcohol and an aqueous solution are mixed, and a first mixed suspension is formed; mixing a short-chain silane coupling agent with ethanol and an aqueous solution to form a second mixed suspension; step S2, uniformly dispersing inorganic nanoparticles in an ethanol-water mixed solution by utilizing emulsifying equipment; mixing the solutions obtained in the steps S1 and S2, reacting in a container, filtering and washing the obtained product, and drying to obtain modified inorganic nanoparticles; mixing the dried TPU particles with the modified inorganic nano powder, and granulating; and uniformly mixing the modified TPU particles, the raw material particles and an antioxidant according to a set amount, putting the mixture into casting equipment for processing, and applying pressure to the extruded viscous TPU material, so that the extruded viscous TPU material is directionally and uniformly stretched and cooled, thereby obtaining the modified TPU film. According to the preparation method, the dispersity and interface bonding strength of the inorganic nanoparticles in the TPU film can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical materials and relates to a TPU film, in particular to a high-temperature-resistant and wear-resistant modified TPU film and a preparation method thereof. Background Art

[0002] Thermoplastic polyurethane (TPU) is a type of elastomer with high strength, high toughness, and highly controllable structure and performance. It has been successfully applied in the fields of medical treatment, packaging, electronics, sports products, automobiles, and building insulation. However, ordinary TPU films can be used for a long time below 80°C, but can only maintain their excellent performance for a few hours at high temperatures (especially above 120°C). Inorganic nanoparticles have the advantages of large specific surface area, high activity, and can effectively change the thermal conductivity process of the material. Using them in the filling and modification process of TPU films not only helps to improve the mechanical properties and crystallization properties of TPU films and extend the service life of the materials, but also can further increase the operating temperature of TPU films. By further improving the compatibility between inorganic nanoparticles and TPU molecular chains, it is conducive to the preparation of TPU films with excellent comprehensive performance, wear resistance, and high temperature resistance.

[0003] Chinese invention patent CN115895238A discloses a method for improving the heat resistance of TPU film by adding glass fiber, carbon fiber and silica, but this method has complex raw material components and is not conducive to large-scale production; Chinese invention patent CN111454564A provides a method for preparing high-temperature resistant TPU film by adding glass microbeads, but neither of the above two preparation methods solves the problem of agglomeration of inorganic nanomaterials themselves and in TPU materials, thereby affecting the overall performance of TPU film products.

[0004] In view of this, there is an urgent need to design a new TPU film to overcome at least some of the above-mentioned defects of the existing TPU film. Summary of the Invention

[0005] The present invention provides a high-temperature-resistant and wear-resistant modified TPU film and a preparation method thereof, which can effectively reduce the agglomeration of inorganic nanoparticles, significantly improve the dispersibility and interfacial bonding strength of inorganic nanoparticles in the TPU film, thereby improving the wear resistance and high-temperature resistance of the TPU film and helping to improve the overall performance of the TPU film.

[0006] In order to solve the above technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0007] A method for preparing a high-temperature-resistant and wear-resistant modified TPU film, the preparation method comprising:

[0008] Step S1, mixing a long-chain silane coupling agent with ethanol and an aqueous solution to form a first mixed suspension, adding a basic solution dropwise to adjust the pH value of the first mixed suspension to a set value, and reacting at room temperature for a set time to complete hydrolysis; mixing a short-chain silane coupling agent with ethanol and an aqueous solution to form a second mixed suspension, adding an acidic solution dropwise to adjust the pH value of the second mixed suspension to a set value, and reacting at room temperature for a set time to fully hydrolyze;

[0009] Step S2: using an emulsification device to uniformly disperse the inorganic nanoparticles in an ethanol-water mixed solution;

[0010] Step S3: Mix the solutions obtained in step S1 and step S2 in a first container, install a reflux condenser, and react for a set time under heating and stirring conditions. After completion, filter and wash the resulting product, and dry it in a drying equipment for a set time to obtain modified inorganic nanoparticles;

[0011] Step S4, mixing the dried TPU particles and the modified inorganic nanopowder evenly, placing the mixture into an extruder, mixing and plasticizing, extruding and pelletizing the mixture to obtain inorganic nanoparticle-modified TPU particles, and drying and removing water;

[0012] Step S5: Take a set amount of modified TPU particles, TPU raw material particles and antioxidant, mix them evenly, put them into a casting device for processing, and apply pressure to the extruded viscous TPU material to make it directional and uniformly stretched and cooled to obtain a modified TPU film.

[0013] As an embodiment of the present invention, in step S1, the long-chain silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane, and aminoethylaminopropylmethyldimethoxysilane;

[0014] As an embodiment of the present invention, in step S1, the mass ratio of the long-chain coupling agent, ethanol and water in the first mixed suspension is 1:(1-10):(1-10); the pH value of the first mixed suspension is adjusted to 8-11; and the reaction time is 3-7 hours.

[0015] As an embodiment of the present invention, in step S1, the alkaline solution includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, ammonium bicarbonate, and sodium carbonate; the acidic solution includes at least one of carbonic acid, acetic acid, oxalic acid, nitrous acid, hypochlorous acid, and phosphoric acid.

[0016] As an embodiment of the present invention, in step S1, the short-chain silane coupling agent includes at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, 3-aminopropyldimethoxymethylsilane, and dimethyldimethoxysilane.

[0017] As an embodiment of the present invention, in step S1, the mass ratio of the short-chain coupling agent, ethanol and water in the second mixed suspension is 1:(1-9):(1-9); the pH value of the second mixed suspension is adjusted to 3-6; and the reaction time is 3-7 hours.

[0018] As an embodiment of the present invention, in step S2, the inorganic nanoparticles include at least one of barium sulfate, silicon oxide, titanium dioxide, kaolin, and calcium carbonate; and the particle size of the inorganic nanoparticles is 80 to 140 nm.

[0019] As an embodiment of the present invention, in step S3, the heating temperature is 80-140°C and the rotation speed is 400-1000 r / min;

[0020] The mass ratio of the inorganic nanoparticles to the long-chain and short-chain coupling agents is 1:(0.1-0.4):(0.1-0.4).

[0021] As an embodiment of the present invention, in step S4, the Shore hardness of the TPU particles is 85-95A; the mass ratio of the inorganic nanoparticles to the TPU particles is 1:(15-30); and the processing temperature is 150-220°C.

[0022] As an embodiment of the present invention, in step S5, the mass ratio of the modified TPU particles to the TPU raw material particles is 1:(10-30); and the processing temperature is 150-230°C.

[0023] As an embodiment of the present invention, in step S5, the antioxidant includes at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant to the TPU raw material particles is 1:(100-200).

[0024] According to another aspect of the present invention, the following technical solution is adopted: a high-temperature-resistant and wear-resistant modified TPU film prepared by the above-mentioned preparation method.

[0025] As an embodiment of the present invention, the high-temperature-resistant and wear-resistant modified TPU film includes TPU raw material particles, inorganic nanoparticles and an antioxidant; the inorganic nanoparticles are modified inorganic nanoparticles obtained through step S3.

[0026] As an embodiment of the present invention, the antioxidant includes at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant, the inorganic nanoparticles, and the TPU raw material particles is 1:(1-3):(100-200).

[0027] The beneficial effects of the present invention are as follows: the high-temperature resistant and wear-resistant modified TPU film and the preparation method thereof proposed in the present invention adopt a method of grafting and modifying inorganic nanoparticles by combining a short-chain coupling agent and a long-chain coupling agent, thereby effectively reducing the agglomeration of inorganic nanoparticles. At the same time, the silane coupling agent grafted on the surface of the inorganic nanoparticles can interact with the TPU molecular chain through electrostatic attraction or chemical bonds, significantly improving the dispersibility and interfacial bonding strength of the inorganic nanoparticles in the TPU film, thereby improving the wear resistance and high-temperature resistance of the TPU film and helping to improve the comprehensive performance of the TPU film.

[0028] This invention incorporates inorganic nanoparticles with high wear resistance and excellent thermal conductivity into a TPU matrix. Using a combination of long-chain and short-chain coupling agents for grafting and modification, the inorganic nanoparticles are fully covered on their surface. This results in uniform dispersion of the modified inorganic nanoparticles within the TPU film and excellent compatibility with the TPU molecular chains. The invention offers a simple preparation method, stable product performance, and widespread application in a variety of fields.

[0029] The present invention takes into account the problems of insufficient modification due to steric hindrance effect when using a single long-chain coupling agent to modify inorganic nanoparticles, and a large number of active groups still exposed on the surface of the inorganic nanoparticles causing aggregation. The surface of the inorganic nanoparticles is fully grafted and covered by a combination of short-chain and long-chain coupling agents, thereby avoiding the agglomeration of inorganic nanoparticles in the TPU film and effectively improving the interfacial compatibility between the inorganic filler and the organic matrix. Benefiting from the excellent performance of the inorganic nanoparticles, the TPU film produced after adding the modified inorganic nanoparticles has excellent wear resistance and outstanding heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for preparing a high-temperature-resistant and wear-resistant modified TPU film in one embodiment of the present invention. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0033] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments described. The same or similar existing technical means and some technical features of the embodiments are mutually replaced within the scope of the description and protection of the present invention.

[0034] Unless otherwise indicated, implied from the context, or customary in the art, all parts and percentages in this application are based on weight, and the test and characterization methods used are current as of the filing date of this application. Where applicable, the contents of any patents, patent applications, or publications referred to in this application are incorporated herein by reference in their entirety, and their equivalent patent families are also incorporated by reference, especially with respect to definitions of synthetic techniques, product and processing designs, polymers, comonomers, initiators, or catalysts disclosed in these documents in the art. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition of the term provided in this application shall prevail.

[0035] Numerical ranges in this application are approximate values, so unless otherwise stated, they may include numerical values outside the range. Numerical ranges include all numerical values from the lower limit to the upper limit increased by 1 unit, provided that there is an interval of at least 2 units between any lower value and any higher value. For example, if the recorded component, physical or other properties (such as molecular weight, melt index, etc.) are 100 to 1000, it is meant that all individual numerical values are clearly enumerated, such as 100, 101, 102, etc., and all subranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For a range comprising a numerical value less than 1 or comprising a fraction greater than 1 (such as 1.1, 1.5, etc.), 1 unit is appropriately considered to be 0.0001, 0.001, 0.01 or 0.1. For a range comprising a single digit less than 10 (such as 1 to 5), 1 unit is typically considered to be 0.1. These are merely specific examples of what is intended, and all possible combinations of values between the lowest and highest values recited are considered to be expressly stated in this application. It should also be noted that the terms "first," "second," etc. herein do not limit the order of precedence, but are only used to distinguish substances of different structures.

[0036] When used with respect to chemical compounds, unless expressly stated otherwise, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). In addition, nouns using "a," "an," or "the" also include their plural forms unless expressly stated otherwise.

[0037] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any other components, steps or processes and are irrelevant to whether these other components, steps or processes are disclosed in this application. To eliminate any doubt, all compositions using the terms "comprising", "including", or "having" in this application may include any additional additives, excipients or compounds unless expressly stated otherwise. In contrast, the term "essentially consisting of" excludes any other components, steps or processes from the scope of any description of the term below, except those necessary for operational performance. The term "consisting of" does not include any components, steps or processes that are not specifically described or listed. Unless expressly stated otherwise, the term "or" refers to the listed members alone or in any combination thereof.

[0038] The description of the steps in each embodiment in the specification is only for the convenience of explanation, and the implementation method of this application is not limited by the order of implementation of the steps.

[0039] The present invention discloses a method for preparing a high-temperature-resistant and wear-resistant modified TPU film. Figure 1 This is a flow chart of a method for preparing a high-temperature and wear-resistant modified TPU film according to an embodiment of the present invention; Figure 1 , the preparation method comprises:

[0040] [Step S1] Mixing a long-chain silane coupling agent with ethanol and an aqueous solution to form a first mixed suspension, adding a basic solution dropwise to adjust the pH value of the first mixed suspension to a set value, and reacting at room temperature for a set time to complete hydrolysis; Mixing a short-chain silane coupling agent with ethanol and an aqueous solution to form a second mixed suspension, adding an acidic solution dropwise to adjust the pH value of the second mixed suspension to a set value, and reacting at room temperature for a set time to fully hydrolyze;

[0041] [Step S2] uniformly dispersing the inorganic nanoparticles in an ethanol-water mixed solution using an emulsification device (e.g., a continuous high-shear emulsification device);

[0042] [Step S3] Mixing the solutions obtained in step S1 and step S2 in a first container (e.g., a three-necked flask), installing a reflux condenser, and reacting for a set time under heating and stirring conditions. After completion, filtering and washing the resulting product, and drying it in a drying device (e.g., an oven) for a set time to obtain modified inorganic nanoparticles;

[0043] [Step S4] The dried TPU particles and the modified inorganic nanopowder are mixed evenly and then placed in an extrusion device (such as a twin-screw extruder) for mixing and plasticizing, extrusion and pelletization to obtain inorganic nanoparticle-modified TPU particles, which are then dried to remove water;

[0044] [Step S5] Take a set amount of modified TPU particles, TPU raw material particles and antioxidant, mix them evenly, put them into a casting equipment (such as a twin-screw extrusion casting equipment) for processing, and apply pressure to the extruded viscous TPU material (such as using multi-roller pressure to act on the extruded viscous TPU material) to make it directional and uniformly stretched and cooled to obtain a modified TPU film.

[0045] In one embodiment of the present invention, in step S1, the long-chain silane coupling agent may include at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane, and aminoethylaminopropylmethyldimethoxysilane.

[0046] The mass ratio of the long-chain coupling agent, ethanol and water in the first mixed suspension can be 1:(1-10):(1-10). In one embodiment, the mass ratio of the long-chain coupling agent, ethanol and water is 1:(2-8):(2-8). The pH value of the first mixed suspension is adjusted to 8-11, more preferably 8-10. The reaction time is 3-7 hours. In one embodiment, the reaction time is 4-7 hours.

[0047] The alkaline solution includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, ammonium bicarbonate, and sodium carbonate.

[0048] The short-chain silane coupling agent may include at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, 3-aminopropyldimethoxymethylsilane, and dimethyldimethoxysilane.

[0049] The mass ratio of the short-chain coupling agent, ethanol and water in the second mixed suspension can be 1:(1-9):(1-9); in one embodiment, the mass ratio of the short-chain coupling agent, ethanol and water is 1:(2-9):(2-9); the pH value of the second mixed suspension is adjusted to 3-6, more preferably 4-6; the reaction time is 3-7 hours, and in one embodiment, the reaction time is 4-7 hours.

[0050] The acidic solution includes at least one of carbonic acid, acetic acid, oxalic acid, nitrous acid, hypochlorous acid, and phosphoric acid.

[0051] In step S2, the inorganic nanoparticles may include at least one of barium sulfate, silicon oxide, titanium dioxide, kaolin, and calcium carbonate; the particle size of the inorganic nanoparticles may be 80 to 140 nm. In one embodiment, the particle size of the inorganic nanoparticles is 80 to 130 nm.

[0052] In step S3, the heating temperature can be 80-140°C, and the rotation speed can be 400-1000 r / min; in one embodiment, the heating temperature is 80-130°C, and the rotation speed is 400-800 r / min; the mass ratio of the inorganic nanoparticles to the long-chain and short-chain coupling agents can be 1:(0.1-0.4):(0.1-0.4), and in one embodiment, the mass ratio of the inorganic nanoparticles to the long-chain and short-chain coupling agents is 1:(0.2-0.4):(0.2-0.4).

[0053] In step S4, the Shore hardness of the TPU particles can be 85-95A. In one embodiment, the Shore hardness of the TPU particles is 85-92A. The mass ratio of the inorganic nanoparticles to the TPU particles is 1:(15-30). In one embodiment, the mass ratio of the inorganic nanoparticles to the TPU particles is 1:(15-30). The processing temperature can be 150-220°C. In one embodiment, the processing temperature is 160-220°C.

[0054] In step S5, the mass ratio of the modified TPU particles to the TPU raw material particles can be 1:(10-30). In one embodiment, the mass ratio of the modified TPU particles to the TPU raw material particles is 1:(15-25). The processing temperature is 150-230°C. In one embodiment, the processing temperature is 180-230°C.

[0055] The antioxidant may include at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant to the TPU raw material particles is 1:(100-200). In one embodiment, the mass ratio of the antioxidant to the TPU raw material particles is 1:(120-200).

[0056] The present invention also discloses a high-temperature, wear-resistant, modified TPU film produced using the above-described preparation method. In one embodiment of the present invention, the high-temperature, wear-resistant, modified TPU film comprises TPU raw material particles, inorganic nanoparticles, and an antioxidant; the inorganic nanoparticles are the modified inorganic nanoparticles produced in step S3.

[0057] The antioxidant includes at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant, the inorganic nanoparticles, and the TPU raw material particles can be 1:(1-3):(100-200).

[0058] Example 1

[0059] In this embodiment, the method for preparing the high temperature resistant and wear resistant modified TPU film of the present invention comprises the following steps:

[0060] Step S1, add 5.0g of γ-aminopropyltriethoxysilane to 60.0g of ethanol and aqueous solution with a mass ratio of 1:2, add ammonia water dropwise to adjust the pH of the mixed suspension to 8-9, and react at room temperature for 4h until the hydrolysis is complete; take another 6.0g of methyltriethoxysilane and disperse it in 48.0g of ethanol and aqueous solution with a mass ratio of 3:5, add oxalic acid solution dropwise to adjust the pH of the solution to 3-4, and react at room temperature for 4h to fully hydrolyze it.

[0061] Step S2: simultaneously using a continuous high shear emulsification device to uniformly disperse 100.0 g of barium sulfate in 1.0 kg of a mixed solution of ethanol and water with a mass ratio of 1:1;

[0062] Step S3: Mix the solutions obtained in steps 1 and 2 in a three-necked flask, install a reflux condenser, and react in an oil bath at 92° C. and a stirring speed of 300 r / min for 6.0 h. After completion, filter and wash the resulting product, and dry it in an oven for 12 h to obtain modified inorganic nanoparticles;

[0063] Step S4: The dried TPU particles and modified inorganic nanoparticles are mixed uniformly at a mass ratio of 19:1, placed in a twin-screw extruder, mixed and plasticized, extruded and pelletized to obtain inorganic nanoparticle-modified TPU particles, and dried to remove water (in one embodiment, specific process parameters can be found in Table 1);

[0064] Step S5: A certain amount of raw material particles, modified TPU particles, and antioxidant are mixed evenly in a mass ratio of 300:15:2, and placed in a twin-screw extrusion casting device for processing (in one embodiment, the specific process parameters can be referred to as shown in Table 2), and multi-roller pressure is applied to the extruded viscous TPU material to make it uniformly stretched in a directional manner and cooled to obtain a modified TPU film.

[0065] Table 1 Process parameters of twin-screw extruder granulator

[0066] Zone 1 / ℃ Zone 2 / ℃ Zone 3 / ℃ Zone 4 / ℃ Zone 5 / ℃ Zone 6 / ℃ Zone 7 / ℃ 175-185 200-210 200-210 200-210 195-205 190-200 195-205 Zone 8 / ℃ Zone 9 / ℃ Zone 10 / ℃ Zone 11 / ℃ Zone 12 / ℃ Host speed / rpm <![CDATA[Pelletizing knife speed / r·min -1 > 175-185 200-210 200-210 200-210 175-185 350-400 350-400

[0067] Table 2 Casting extruder process parameters

[0068]

[0069] Example 2:

[0070] In this embodiment, the method for preparing the high temperature resistant and wear resistant modified TPU film of the present invention comprises the following steps:

[0071] Step S1, add 6.0g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to 90.0g of ethanol and aqueous solution with a mass ratio of 1:1, add ammonium bicarbonate solution dropwise to adjust the pH of the mixed suspension to 8-9, and react at room temperature for 3h until the hydrolysis is complete; take another 5.0g of 3-aminopropyldimethoxymethylsilane and disperse it in 36.0g of ethanol and aqueous solution with a mass ratio of 1:3, add acetic acid solution dropwise to adjust the pH of the solution to 3-4, and react at room temperature for 4h to fully hydrolyze it.

[0072] Step S2: uniformly dispersing 70.0 g of titanium dioxide in 1.0 kg of a mixed solution of ethanol and water at a mass ratio of 1:1 using a continuous high shear emulsification device;

[0073] Step S3: Mix the solutions obtained in steps 1 and 2 in a three-necked flask, install a reflux condenser, and react in an oil bath at 98° C. and a stirring speed of 500 r / min for 8.0 h. After completion, filter and wash the resulting product, and dry it in an oven for 12 h to obtain modified inorganic nanoparticles;

[0074] Step S4: The dried TPU particles and modified inorganic nanoparticles are mixed uniformly at a mass ratio of 19:1, placed in a twin-screw extruder, mixed and plasticized, extruded and pelletized to obtain inorganic nanoparticle-modified TPU particles, and dried to remove water (in one embodiment, specific process parameters can be found in Table 1);

[0075] Step S5: A certain amount of raw material particles, modified TPU particles, and antioxidant are mixed evenly in a mass ratio of 300:15:2, and placed in a twin-screw extrusion casting device for processing (in one embodiment, the specific process parameters can be referred to as shown in Table 2), and multi-roller pressure is applied to the extruded viscous TPU material to make it uniformly stretched in a directional manner and cooled to obtain a modified TPU film.

[0076] Example 3:

[0077] In this embodiment, the method for preparing the high temperature resistant and wear resistant modified TPU film of the present invention comprises the following steps:

[0078] Step S1, adding 8.0g of aminoethylaminopropylmethyldimethoxysilane to 100.0g of ethanol and aqueous solution in a mass ratio of 2:3, adding sodium hydroxide solution dropwise to adjust the pH of the mixed suspension to 8-9, and reacting at room temperature for 2h until the hydrolysis is complete; taking another 4.0g of dimethyldimethoxysilane and dispersing it in 40.0g of ethanol and aqueous solution in a mass ratio of 1:7, adding carbonic acid solution dropwise to adjust the pH of the solution to 3-4, and reacting at room temperature for 3h to fully hydrolyze it.

[0079] Step S2: uniformly dispersing 80.0 g of calcium carbonate in 1.0 kg of a mixed solution of ethanol and water at a mass ratio of 1:1 using a continuous high shear emulsification device;

[0080] Step S3: Mix the hydrolyzed solutions obtained in steps 1 and 2 in a three-necked flask, install a reflux condenser, and react in an oil bath at 95° C. and a stirring speed of 450 r / min for 5 h. After completion, filter and wash the resulting product, and dry it in an oven for 12 h to obtain modified inorganic nanoparticles;

[0081] Step S4: The dried TPU particles and modified inorganic nanoparticles are mixed uniformly at a mass ratio of 19:1, placed in a twin-screw extruder, mixed and plasticized, extruded and pelletized to obtain inorganic nanoparticle-modified TPU particles, and dried to remove water (in one embodiment, specific process parameters can be found in Table 1);

[0082] Step S5: A certain amount of raw material particles, modified TPU particles, and antioxidant are mixed evenly in a mass ratio of 300:15:2, and placed in a twin-screw extrusion casting device for processing (in one embodiment, the specific process parameters can be referred to as shown in Table 2), and multi-roller pressure is applied to the extruded viscous TPU material to make it uniformly stretched in a directional manner and cooled to obtain a modified TPU film.

[0083] Comparative Example 1:

[0084] The difference between this comparative example and the embodiment is that no inorganic nanoparticles are added and pure TPU raw materials are used to produce the TPU film.

[0085] Comparative Example 2:

[0086] The difference between this comparative example and Example 1 is that the same mass of unmodified inorganic nanoparticles are added, and other conditions remain the same.

[0087] Performance Testing

[0088] The high temperature resistance of the TPU films prepared in Examples 1-5 and Comparative Examples 1-2 was determined according to the following method: samples cut into dumbbell shapes were subjected to a high-temperature long-term storage experiment at 80°C for 200 h, 100°C for 200 h, 120°C for 200 h, and 140°C for 200 h. The elongation at break of the TPU film samples was tested before and after high-temperature storage treatment according to the GB / T 528-2009 method, and the ratio of the two was taken as the elongation at break retention rate.

[0089] Table 3 Comparison table of test results of elongation at break of various embodiments and comparative examples

[0090]

[0091]

[0092] As shown in Table 3, the elongation at break retention rate of the TPU film prepared after adding modified inorganic nanoparticles is better than that of Comparative Examples 1-2, indicating that the heat resistance of the samples of Examples 1-3 is better, and the modified inorganic nanoparticles effectively improve the heat resistance of the TPU film; in addition, with the increase of the aging temperature, the rate of decrease of the elongation at break retention rate is faster, because under high temperature environment, the decomposition of allophanate or ester groups inside the material is caused, but at higher temperatures, Examples 1-3 still have good elongation at break retention rate; among them, there is a certain gap between the elongation at break retention rates of Comparative Example 2 and Examples 1-3, because the unmodified inorganic nanoparticles agglomerate in the material, resulting in stress concentration in the material during stress stretching, which causes the material to rupture.

[0093] The wear index was calculated using the Taber abrasion tester using the Taber method specified in GB / TF30314-2013, Determination of the Abrasion Resistance of Rubber or Plastic Coated Fabrics. The samples were weighed before and after the friction test, and each sample was measured three times in parallel. The wear index was calculated using the formula: Wear index (mg) = wear mass loss / number of test frictions × 100.

[0094] Table 4 Comparison of wear resistance test results of various embodiments and comparative examples

[0095] Wear mass (mg) Comparative Example 1 157 Comparative Example 2 88 Example 1 79 Example 2 73 Example 3 75

[0096] As shown in Table 4, it can be seen from Comparative Example 1 that the wear quality of the TPU film without the addition of inorganic nanoparticles is higher, indicating that its wear resistance is poor; in Comparative Example 2, the wear quality is significantly reduced after the addition of inorganic nanoparticles, indicating that the addition of inorganic nanoparticles helps to improve its wear resistance; Examples 1-3 show that the addition of modified inorganic nanoparticles significantly improves the wear resistance of the TPU film.

[0097] In summary, the preparation method of the high-temperature resistant and wear-resistant modified TPU film proposed in the present invention adopts a method of grafting and modifying inorganic nanoparticles by combining a short-chain coupling agent and a long-chain coupling agent, which effectively reduces the agglomeration of inorganic nanoparticles. At the same time, the silane coupling agent grafted on the surface of the inorganic nanoparticles can interact with the TPU molecular chain through electrostatic attraction or chemical bonds, significantly improving the dispersibility and interfacial bonding strength of the inorganic nanoparticles in the TPU film, thereby improving the wear resistance and high-temperature resistance of the TPU film and helping to improve the comprehensive performance of the TPU film.

[0098] This invention incorporates inorganic nanoparticles with high wear resistance and excellent thermal conductivity into a TPU matrix. Using a combination of long-chain and short-chain coupling agents for grafting and modification, the inorganic nanoparticles are fully covered on their surface. This results in uniform dispersion of the modified inorganic nanoparticles within the TPU film and excellent compatibility with the TPU molecular chains. The invention offers a simple preparation method, stable product performance, and widespread application in a variety of fields.

[0099] The present invention takes into account the problems of insufficient modification due to steric hindrance effect when using a single long-chain coupling agent to modify inorganic nanoparticles, and a large number of active groups still exposed on the surface of the inorganic nanoparticles causing aggregation. The surface of the inorganic nanoparticles is fully grafted and covered by a combination of short-chain and long-chain coupling agents, thereby avoiding the agglomeration of inorganic nanoparticles in the TPU film and effectively improving the interfacial compatibility between the inorganic filler and the organic matrix. Benefiting from the excellent performance of the inorganic nanoparticles, the TPU film produced after adding the modified inorganic nanoparticles has excellent wear resistance and outstanding heat resistance.

[0100] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The description and application of the present invention here are illustrative and are not intended to limit the scope of the present invention to the above-described embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. Variations and changes to the embodiments disclosed here are possible, and the replacement of the embodiments and various equivalent components are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the present invention. Other variations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A method for preparing a high-temperature-resistant and wear-resistant modified TPU film, characterized in that: The preparation method comprises: Step S1, mixing a long-chain silane coupling agent with ethanol and an aqueous solution to form a first mixed suspension, adding a basic solution dropwise to adjust the pH value of the first mixed suspension to a set value, and reacting at room temperature for a set time to complete hydrolysis; mixing a short-chain silane coupling agent with ethanol and an aqueous solution to form a second mixed suspension, adding an acidic solution dropwise to adjust the pH value of the second mixed suspension to a set value, and reacting at room temperature for a set time to fully hydrolyze; Step S2: using an emulsification device to uniformly disperse the inorganic nanoparticles in an ethanol-water mixed solution; Step S3: Mix the solutions obtained in step S1 and step S2 in a first container, install a reflux condenser, and react for a set time under heating and stirring conditions. After completion, filter and wash the resulting product, and dry it in a drying equipment for a set time to obtain modified inorganic nanoparticles; Step S4, mixing the dried TPU particles and the modified inorganic nanopowder evenly, placing the mixture into an extruder, mixing and plasticizing, extruding and pelletizing the mixture to obtain inorganic nanoparticle-modified TPU particles, and drying and removing water; Step S5: Take a set amount of modified TPU particles, TPU raw material particles and antioxidant, mix them evenly, put them into a casting device for processing, and apply pressure to the extruded viscous TPU material to make it directional and uniformly stretched and cooled to obtain a modified TPU film.

2. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, wherein: In step S1, the long-chain silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane, and aminoethylaminopropylmethyldimethoxysilane; In step S1, the mass ratio of the long-chain coupling agent, ethanol and water in the first mixed suspension is 1:(1-10):(1-10); the pH value of the first mixed suspension is adjusted to 8-11; and the reaction time is 3-7 hours.

3. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, wherein: In step S1, the alkaline solution includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, ammonium bicarbonate, and sodium carbonate; the acidic solution includes at least one of carbonic acid, acetic acid, oxalic acid, nitrous acid, hypochlorous acid, and phosphoric acid.

4. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, wherein: In step S1, the short-chain silane coupling agent includes at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, 3-aminopropyldimethoxymethylsilane, and dimethyldimethoxysilane; In step S1, the mass ratio of the short-chain coupling agent, ethanol and water in the second mixed suspension is 1:(1-9):(1-9); the pH value of the second mixed suspension is adjusted to 3-6; and the reaction time is 3-7 hours.

5. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, wherein: In step S2, the inorganic nanoparticles include at least one of barium sulfate, silicon oxide, titanium dioxide, kaolin, and calcium carbonate; and the particle size of the inorganic nanoparticles is 80 to 140 nm.

6. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, characterized in that: In step S3, the heating temperature is 80-140° C., the rotation speed is 400-1000 r / min; the mass ratio of the inorganic nanoparticles to the long-chain and short-chain coupling agents is 1:(0.1-0.4):(0.1-0.4); In step S4, the Shore hardness of the TPU particles is 85-95A; the mass ratio of the inorganic nanoparticles to the TPU particles is 1:(15-30); and the processing temperature is 150-220°C; In step S5, the mass ratio of the modified TPU particles to the TPU raw material particles is 1:(10-30); and the processing temperature is 150-230°C.

7. The method for preparing the high temperature resistant and wear resistant modified TPU film according to claim 1, characterized in that: In step S5, the antioxidant includes at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant to the TPU raw material particles is 1:(100-200).

8. A high-temperature-resistant and wear-resistant modified TPU film prepared by the preparation method according to any one of claims 1 to 7.

9. The high temperature and wear resistant modified TPU film according to claim 8, characterized in that: The high-temperature-resistant and wear-resistant modified TPU film comprises TPU raw material particles, inorganic nanoparticles and an antioxidant; the inorganic nanoparticles are modified inorganic nanoparticles obtained in step S3.

10. The high temperature and wear resistant modified TPU film according to claim 8, characterized in that: The antioxidant includes at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and tris(nonylphenol)phosphite; the mass ratio of the antioxidant, the inorganic nanoparticles, and the TPU raw material particles is 1:(1-3):(100-200).

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