Thermoplastic polyurethane condensate with high weather resistance and yellowing resistance and manufacturing method thereof

Abstract

The invention discloses a thermoplastic polyurethane condensate with high weather resistance and yellowing resistance and a manufacturing method thereof. The thermoplastic polyurethane condensate comprises thermoplastic polyurethane, an ultraviolet light absorber and a light stabilizer combination. The thermoplastic polyurethane is formed by a reaction composition, and the reaction composition comprises an isocyanate component, a polyol component and a dihydric alcohol chain extender component. The polyol component is selected from a group consisting of a polyether polyol, a polyester polyol and a polycaprolactone polyol. The light stabilizer combination is a combination of a phosphorus light stabilizer, a hindered amine light stabilizer and a hindered phenol light stabilizer. Therefore, the thermoplastic polyurethane condensate provided by the invention can enhance the yellowing resistance and weather resistance of a film product in various environments or in the production and processing process.

Description

Technical Field

[0001] The present invention relates to a thermoplastic polyurethane cured product, particularly to a thermoplastic polyurethane cured product with high weather resistance and yellowing resistance, such as a particulate cured product that can be processed into a film. Background Art

[0002] Thermoplastic polyurethane (TPU) is an environmentally friendly polymer, and the products made from it cover the range of industrial applications and civilian necessities. In addition, TPU materials have excellent physical and mechanical properties and can be compounded with other materials such as fibers and polyesters to create new multifunctional products.

[0003] Currently, the TPU materials commonly used on the market have very poor yellowing resistance. As the products made from them are used for a longer time, yellowing will start to occur under the influence of ultraviolet light. For example, a TPU transparent case changes from colorless and transparent to orange-yellow. In addition, during the production of TPU materials, there will inevitably be some infusible small crystals, resulting in appearance defects such as crystal points and flow marks on the processed film, which affect the appearance quality of the product.

[0004] In addition, the existing thermoplastic polyurethanes have a wide molecular weight distribution and large changes in melt viscosity, which is not only not conducive to melt processing into a film, and the film lamination processed products are prone to crystal points, but also easily leads to a decline in the physical properties of the product. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide, in view of the deficiencies of the prior art, a thermoplastic polyurethane cured product with high weather resistance and yellowing resistance, which is suitable for film lamination processing, and the film made therefrom has good appearance quality. The present invention also provides a method for manufacturing a thermoplastic polyurethane cured product.

[0006] To solve the above-mentioned technical problem, one of the technical solutions adopted by the present invention is to provide a thermoplastic polyurethane cured product with high weather resistance and yellowing resistance, which comprises a thermoplastic polyurethane, an ultraviolet absorber, and a combination of light stabilizers. Based on the total weight of the thermoplastic polyurethane cured product with high weather resistance and yellowing resistance, the content of the thermoplastic polyurethane is 97% by weight to 99% by weight, the content of the ultraviolet absorber is 0.1% by weight to 0.5% by weight, and the content of the combination of light stabilizers is 0.3% by weight to 1% by weight. Among them, the thermoplastic polyurethane is formed from a reaction composition, the reaction composition contains an isocyanate component, a polyol component, and a diol chain extender component, and the polyol component is selected from the group consisting of polyether polyols, polyester polyols, and polycaprolactone polyols. In addition, the combination of light stabilizers is a combination of a phosphorus-based light stabilizer, a hindered amine light stabilizer, and a hindered phenol light stabilizer.

[0007] To solve the technical problem, another technical solution adopted by the present invention is to provide a method for manufacturing a thermoplastic polyurethane cured product with high weather resistance and anti-yellowing, which includes: combining a reaction composition, an ultraviolet absorber, and a light stabilizer combination and adding them into an extruder for polymerization reaction, wherein the NCO / OH ratio is 0.98 to 1.02 to form a thermoplastic polyurethane composition; and extruding and granulating the thermoplastic polyurethane composition to obtain a plurality of thermoplastic polyurethane cured products with high weather resistance and anti-yellowing. Based on the total weight of the thermoplastic polyurethane cured product with high weather resistance and anti-yellowing, the content of the thermoplastic polyurethane is 97% to 99% by weight, the content of the ultraviolet absorber is 0.1% to 0.5% by weight, and the content of the light stabilizer combination is 0.3% to 1% by weight. Additionally, the light stabilizer combination is a combination of a phosphorus-based light stabilizer, a hindered amine light stabilizer, and a hindered phenol light stabilizer.

[0008] Furthermore, the weight ratio of the phosphorus-based light stabilizer, the hindered amine light stabilizer, and the hindered phenol light stabilizer is 1:1.5:3.

[0009] Furthermore, in the reaction composition, relative to 100 parts by weight of the polyol component, the amount of the isocyanate component used is 62 to 66 parts by weight, and the amount of the diol chain extender component used is 13 to 15 parts by weight.

[0010] Furthermore, the isocyanate component is diphenylmethane diisocyanate.

[0011] Furthermore, the diol chain extender component is at least one of a linear diol and a branched diol with a number average molecular weight less than 500 g / mol.

[0012] Furthermore, the diol chain extender is 1,4-butanediol.

[0013] Furthermore, the reaction composition contains stannous octoate as a catalyst, and relative to 100 parts by weight of the polyol component, the amount of the catalyst used is 0.04 to 0.06 parts by weight.

[0014] Furthermore, the ultraviolet absorber is at least one of 2-hydroxy-4-methoxybenzophenone and 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole.

[0015] Further, the phosphorus-based light stabilizer is at least one of tris(2,4-di-tert-butylphenyl) phosphate and tris(2,4-di-tert-butylphenyl) phosphite; the hindered amine light stabilizer is at least one of 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine and poly(butanedioic acid) (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoethanol) ester; the hindered phenol light stabilizer is 2,2'-methylenebis(6-tert-butyl-4-methylphenol).

[0016] Further, the polyester polyol is selected from the group consisting of: poly(1,4-butanediol adipate) diol, poly(ethylene glycol-1,4-butanediol adipate) diol, and poly(hexanediol adipate-succinate) diol; the polyether polyol is selected from the group consisting of: polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0017] Generally speaking, for the high weather resistance and yellowing resistance thermoplastic polyurethane cured product and its manufacturing method provided by the present invention, by virtue of "based on the total weight of the thermoplastic polyurethane cured product, the content of thermoplastic polyurethane is 97% by weight to 99% by weight, the content of the ultraviolet absorber is 0.1% by weight to 0.5% by weight, and the content of the light stabilizer combination is 0.3% by weight to 1% by weight", "the polyol component is selected from the group consisting of polyether polyols, polyester polyols, and polycaprolactone polyols", and "the light stabilizer combination is a combination of a phosphorus-based light stabilizer, a hindered amine light stabilizer, and a hindered phenol light stabilizer", the aesthetics of the thermoplastic polyurethane film can be improved, while ensuring the yellowing resistance and weather resistance of the thermoplastic polyurethane film.

[0018] Furthermore, the high weather resistance and yellowing resistance thermoplastic polyurethane cured product provided by the present invention is used for the film made by lamination coating. Its appearance has no crystal points, good transparency, and excellent yellowing resistance and weather resistance, and has broad application prospects in the field of film products.

[0019] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the provided drawings are only for reference and illustration, and are not used to limit the present invention. Description of the Drawings

[0020] Figure 1This is a flowchart of the manufacturing method of a highly weather-resistant and yellowing-resistant thermoplastic polyurethane cured product of the present invention.

[0021] Figure 2 This is an operation schematic diagram of the highly weather-resistant and yellowing-resistant thermoplastic polyurethane cured product of the present invention for lamination processing. Detailed implementation manners

[0022] The following are specific embodiments to illustrate the implementation manners of the present invention regarding "highly weather-resistant and yellowing-resistant thermoplastic polyurethane cured products and their manufacturing methods". Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Additionally, the drawings of the present invention are only for simple schematic illustration and are not drawn according to actual dimensions. The following implementation manners will further detail the relevant technical content of the present invention, but the disclosed content is not intended to limit the protection scope of the present invention.

[0023] Unless otherwise defined, the terms used in this article have the same meaning as the common understanding of those skilled in the art. The materials involved in each embodiment are commercially available or prepared according to existing technologies without special instructions. The operations or instruments involved in each embodiment are conventional operations or instruments in this field without special instructions.

[0024] Products made of thermoplastic polyurethane (TPU) are easily affected by light (especially ultraviolet light), heat, oxygen, and moisture during various environments or production and processing processes, resulting in deterioration of appearance and mechanical properties. In addition, the molecular weight distribution of thermoplastic polyurethane is relatively wide and the viscosity of the melt changes significantly, which is not conducive to melt processing into thin films, and there are easily crystal points in the lamination processing finished products. Therefore, the present invention proposes a new concept: mixing the reaction composition of thermoplastic polyurethane with selected ultraviolet absorbers and light stabilizers and granulating to obtain a highly weather-resistant and yellowing-resistant thermoplastic polyurethane cured product, which is suitable for lamination processing, and the resulting thin film has no crystal points, good transparency, excellent yellowing resistance and weather resistance, and has broad application prospects in the field of film products.

[0025] Specifically, an embodiment of the present invention provides a thermoplastic polyurethane cured product with high weather resistance and anti-yellowing that embodies the inventive concept, which includes a thermoplastic polyurethane, an ultraviolet absorber, and a light stabilizer combination. Based on the total weight of the thermoplastic polyurethane cured product, the content of the thermoplastic polyurethane is 97% to 99% by weight, the content of the ultraviolet absorber is 0.1% to 0.5% by weight, and the content of the light stabilizer combination is 0.3% to 1% by weight. The thermoplastic polyurethane, ultraviolet absorber, and light stabilizer combination will be described below.

[0026] Thermoplastic polyurethane

[0027] The thermoplastic polyurethane that constitutes the thermoplastic polyurethane cured product of the present invention is formed from a reaction composition, which is characterized in that the reaction composition contains an isocyanate component, a polyol component, and a diol chain extender component.

[0028] In an embodiment of the present invention, the isocyanate component may include polyisocyanate compounds, such as but not limited to compounds having two or more isocyanate groups. Specific examples of the polyisocyanate compounds include: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), 3,3'-dimethylbenzene-4,4'-biphenyl diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), p-phenylene diisocyanate (PPDI) and other aromatic diisocyanates; 4,4'-dicyclohexylmethane diisocyanate (H12MDI), hydrogenated xylylene diisocyanate (H6XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI) and other cycloaliphatic diisocyanates or aliphatic diisocyanates; and modified products or addition compounds of these diisocyanates. The polyisocyanate compounds can be used alone or in combination of two or more.

[0029] Considering the comprehensive performance of the thermoplastic polyurethane film, the isocyanate component contains more than 50% of MDI. Preferably, the isocyanate component contains more than 80% of MDI. More preferably, the isocyanate component is all MDI.

[0030] In an embodiment of the present invention, the polyol component may include high molecular weight polyols with a number average molecular weight of 500 g / mol or more, such as but not limited to polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, polyurethane polyols, acrylic polyols, etc.

[0031] Furthermore, the polyol component may be selected from the group consisting of polyether polyols, polyester polyols, and polycaprolactone polyols. Specific examples of the polyester polyol include: 1,4-butanediol adipate diol, ethylene glycol-1,4-butanediol adipate diol, and hexanediol adipate-succinate diol. It is characterized in that 1,4-butanediol adipate diol is formed by the polymerization reaction of adipic acid and 1,4-butanediol. Ethylene glycol-1,4-butanediol adipate diol is formed by the polymerization reaction of adipic acid, ethylene glycol, and 1,4-butanediol. Hexanediol adipate-succinate diol is formed by the polymerization reaction of adipic acid, succinic acid, and hexanediol. Specific examples of the polyether polyol include: polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. However, the present invention is not limited to the examples given above.

[0032] In practical applications, the high molecular weight polyol (the first polyol) may have a number average molecular weight between 600 g / mol and 2,000 g / mol, which helps to reduce the softening temperature of the formed thermoplastic polyurethane. It is worth noting that when the softening temperature of the thermoplastic polyurethane decreases, most of the thermoplastic polyurethane can be fully melted or softened at the processing temperature of the lamination process. Therefore, problems such as crystal points and flow marks that are likely to occur when the thermoplastic polyurethane is processed into a film can be improved.

[0033] In practical applications, the high molecular weight polyol (the second polyol) may have a number average molecular weight between 1,500 g / mol and 3,000 g / mol to ensure that the formed thermoplastic polyurethane has better mechanical strength.

[0034] In practical applications, the first polyol and the second polyol described above may be used in combination, and the weight ratio range of the first polyol to the second polyol is preferably 1:0.2 - 0.25.

[0035] Furthermore, the first polyol may be selected from the group consisting of polyether polyols, polyester polyols, and polycaprolactone polyols. Similarly, the second polyol may be selected from the group consisting of polyether polyols, polyester polyols, and polycaprolactone polyols. Specific examples of the polyester polyol include: poly(1,4-butylene adipate) diol, poly(ethylene glycol 1,4-butylene adipate) diol, and poly(hexanediol adipate succinate) diol. It is characterized in that poly(1,4-butylene adipate) diol is formed by the polymerization reaction of adipic acid and 1,4-butanediol. Poly(ethylene glycol 1,4-butylene adipate) diol is formed by the polymerization reaction of adipic acid, ethylene glycol, and 1,4-butanediol. Poly(hexanediol adipate succinate) diol is formed by the polymerization reaction of adipic acid, succinic acid, and hexanediol. Specific examples of the polyether polyol include: polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. However, the present invention is not limited to the examples given above.

[0036] In some embodiments, the first polyol and / or the second polyol may be graft-modified via side chains to reduce the crystallinity of the formed thermoplastic polyurethane, thereby improving the phenomenon of forming infusible small crystals in the raw material reaction, which is beneficial to obtaining a high-quality transparent film without crystal points and flow marks. As the graft modifier for the first polyol and / or the second polyol, diols with a carbon chain length from C3 to C10 can be used, such as but not limited to diethylene glycol (DEG), 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, and 3-methyl-1,5-pentanediol.

[0037] In the embodiments of the present invention, the diol chain extender component may be at least one of a linear diol and a branched diol. Among them, the carbon chain length of the linear diol may be C2 to C6, such as but not limited to 1,4-butanediol and ethylene glycol. The carbon chain length of the branched diol may be C3 to C10, such as but not limited to 2-methyl-1,3-propanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol. Preferably, the diol chain extender is 1,4-butanediol.

[0038] The linear diol can endow the formed thermoplastic polyurethane with better mechanical strength. In addition, the branched diol has side chains or ether groups, which can increase the steric hindrance of the molecular chains of the formed thermoplastic polyurethane and reduce the crystallinity of the thermoplastic polyurethane. Therefore, the phenomenon of forming infusible small crystals during the process of manufacturing the thermoplastic polyurethane cured product can be improved, thereby completely eliminating crystal points and flow marks on the film.

[0039] In practical applications, the linear diol and the branched diol can be used in combination. The weight ratio range of the linear diol to the branched diol is preferably 10 - 15:1. It should be noted that adjusting the weight ratio relationship between the linear diol and the branched diol within this range can endow the formed thermoplastic polyurethane with the desired crystallinity and ideal mechanical strength.

[0040] In the embodiments of the present invention, in the reaction composition, relative to 100 parts by weight of the polyol component, the amount of the isocyanate component can be 62 parts by weight to 66 parts by weight, and the amount of the diol chain extender component can be 13 parts by weight to 15 parts by weight. In addition, the NCO / OH ratio (the molar ratio of the NCO groups of the isocyanate component to the OH groups of the polyol and chain extender components) in the polymerization reaction of the reaction composition should be controlled within the range of 0.98 to 1.02, and the range of 0.995 to 1.005 is better, so that the formed thermoplastic polyurethane has characteristics such as stable molecular weight, narrow molecular weight distribution, and good processing fluidity. If the NCO / OH ratio in the polymerization reaction of the reaction composition is not within the above range, the formed thermoplastic polyurethane may have problems such as poor heat resistance and difficulty in processing, and is prone to appearance defects such as crystal points and flow marks after being made into a film.

[0041] In practical applications, the reaction composition can contain a catalyst to accelerate the reaction between the NCO groups of the isocyanate component and the OH groups of the polyol and chain extender components. Suitable catalysts include, but are not limited to, stannous octoate, amine catalysts, bismuth catalysts, and antimony catalysts, with stannous octoate being preferred. In the reaction composition, relative to 100 parts by weight of the polyol component, the amount of the catalyst can be 0.04 parts by weight to 0.06 parts by weight.

[0042] Ultraviolet absorber

[0043] The UV absorber that constitutes the thermoplastic polyurethane cured product of the present invention is selected from benzotriazoles and benzophenones, which can impart excellent resistance to ultraviolet light rotation to the thermoplastic polyurethane. Among them, the benzotriazole UV absorber is preferably 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, and the benzophenone UV absorber is preferably 2-hydroxy-4-methoxybenzophenone.

[0044] In the examples of the present invention, the UV absorber can be at least one of 2-hydroxy-4-methoxybenzophenone and 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole. Therefore, it can prevent or slow down the aging phenomenon caused by ultraviolet irradiation of the thermoplastic polyurethane cured product or its processed products, so as to maintain the hue stability and mechanical properties of the processed products (such as transparent films), and increase their durability under ultraviolet environment.

[0045] Light stabilizer combination

[0046] The light stabilizer combination that constitutes the thermoplastic polyurethane cured product of the present invention is a combination of a phosphorus-based light stabilizer, a hindered amine light stabilizer and a hindered phenol light stabilizer, which can capture the free radicals generated by the photooxidation of ultraviolet light to prevent the further deterioration of the plastic polyurethane cured product or its processed products. That is to say, the light stabilizer combination can remedy the area of photooxidation caused by ultraviolet light to make up for the deficiency of the UV absorber. Therefore, when the light stabilizer combination is used in combination with the UV absorber, it can provide more complete protection for the plastic polyurethane cured product or its processed products.

[0047] In the examples of the present invention, the phosphorus-based light stabilizer is preferably at least one of tris(2,4-di-tert-butylphenyl) phosphate and tris(2,4-di-tert-butylphenyl) phosphite. The hindered amine light stabilizer is preferably 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine

[0048] At least one of (TINUVIN B97) and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidylethanol) succinate. The hindered phenol light stabilizer is preferably 2,2'-methylenebis(6-tert-butyl-4-methylphenol). It should be noted that the preferred phosphorus-based light stabilizer, hindered amine light stabilizer and hindered phenol light stabilizer can synergistically produce excellent light stability, avoiding problems such as yellowing and performance weakening caused by photoaging. Preferably, the weight ratio of the phosphorus-based light stabilizer, hindered amine light stabilizer and hindered phenol light stabilizer is 1:1.5:3.

[0049] Method for manufacturing a thermoplastic polyurethane cured product

[0050] Please refer to Figure 1 , which is a flowchart of the method for manufacturing a thermoplastic polyurethane cured product of the present invention. As Figure 1 shown, the method for manufacturing a thermoplastic polyurethane cured product of the present invention is a continuous method, which includes: Step S100, combining a reaction composition, an ultraviolet absorber and a light stabilizer and adding them into an extruder for polymerization reaction, wherein the NCO / OH ratio is 0.98 to 1.02 to form a thermoplastic polyurethane composition; and Step S102, extruding the thermoplastic polyurethane composition and granulating it to obtain a plurality of thermoplastic polyurethane cured products with high weather resistance and anti-yellowing.

[0051] In Step S100, the reaction composition, ultraviolet absorber, light stabilizer combination and optionally added catalyst and other additives are fed into the extruder (such as a twin-screw reactive extruder) separately or in mixture according to the metering described in the embodiments of the present invention for reaction. The specific types or substances of the reaction composition, ultraviolet absorber, light stabilizer combination and catalyst are as described above and will not be elaborated here. The temperature during the reactive extrusion process is controlled between 150°C and 250°C to facilitate the full progress of the polymerization reaction.

[0052] In actual application, the real-time viscosity of the melt can be monitored online and the feeding amounts of the isocyanate component, polyol component or chain extender component can be adjusted accordingly to control the NCO / OH ratio in the polymerization reaction within the above range, or to maintain a stable melt viscosity during the reactive extrusion process.

[0053] In Step S102, after the thermoplastic polyurethane composition is extruded from the die head, particle-shaped cured products are cut out by underwater granulation, dehydrated and sorted to obtain qualified particle products (particle-shaped thermoplastic polyurethane cured products).

[0054] Cooperate with Figure 2As shown, the thermoplastic polyurethane cured product of the present invention can be used to make a film by extrusion coating. Specifically, the thermoplastic polyurethane cured product is first heated and melted, and then the melt is extruded by an extrusion die head 1 onto a dynamically moving carrier 2 such as release paper or polyester film to form a film layer 3, and the thickness of the film layer 3 can be adjusted as needed.

[0055] The following are the tests conducted according to ASTM G155 standard.

[0056] In this article, the "light fastness stability" is evaluated by the change in hue before and after irradiation with simulated sunlight. Refer to Tables 1 to 3 below. Test pieces made from the raw materials of Examples 1 to 6 and Comparative Examples 1 to 3 are placed in a Q-Sun instrument for testing; the method for making the test pieces is to put 30 grams of TPU pellets into a mold with dimensions of approximately 7 cm × 11 cm × 2 mm (length × width × height), and then hot press them with a hot press molding machine. Test light source: xenon lamp; irradiation intensity: 0.35 watts per square meter (W / m 2 ); irradiation temperature: 28 - 50 °C; irradiation time: 100, 200, 500 hours; irradiation direction: irradiate towards the incident light surface of the test piece. Thereafter, a spectrophotometric luminance meter is used, and based on the JIS K8781-4:2013 standard, the color difference ΔE is used as the criterion for judging the hue change. The longer the irradiation time, the more energy the test piece receives and the easier it is to turn yellow. The smaller the ΔE value shown in Tables 1 to 3, the better the light fastness stability (the better the anti-yellowing effect) of the test piece.

[0057] In Tables 1 to 3, the detailed data of each additive are as follows:

[0058] Ultraviolet absorber: a product of model UV-5411;

[0059] Phosphorus-based light stabilizer: a product of model 6601;

[0060] Hindered amine light stabilizer: a product of model 6602;

[0061] Hindered phenol light stabilizer: a product of model TINUVIN B97.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066]

[0067] Table 3

[0068]

[0069] As can be seen from Table 3, after 100 and 200 hours of simulated sunlight irradiation, the color difference ΔE of the test pieces made of the raw materials of Examples 5 and 6 is below 2, indicating that the degree of hue change is very small and the human eye can basically not distinguish the color difference (usually considered the same color). After 500 hours of simulated sunlight irradiation, the color difference ΔE of the test pieces made of the raw materials of Examples 5 and 6 is not more than 5, which is much smaller than the color difference ΔE (19.5 - 22) of the test pieces made of the raw materials of Comparative Examples 1 to 3, indicating that the combination use of the phosphorus-based light stabilizer, the hindered amine light stabilizer and the hindered phenol light stabilizer in the present invention brings significantly better anti-yellowing effect than the effect of using only one of them or using two of them in combination.

[0070] Advantageous effects of the examples

[0071] The high weather-resistant and anti-yellowing thermoplastic polyurethane cured product and its manufacturing method provided by the present invention, by virtue of "based on the total weight of the thermoplastic polyurethane cured product, the content of the thermoplastic polyurethane is 97% by weight to 99% by weight, the content of the ultraviolet absorber is 0.1% by weight to 0.5% by weight, and the content of the light stabilizer combination is 0.3% by weight to 1% by weight", "the polyol component is selected from the group consisting of polyether polyol, polyester polyol and polycaprolactone polyol", and "the light stabilizer combination is a combination of a phosphorus-based light stabilizer, a hindered amine light stabilizer and a hindered phenol light stabilizer", can improve the aesthetics of the thermoplastic polyurethane film, and at the same time ensure the anti-yellowing property and weather resistance of the thermoplastic polyurethane film.

[0072] Furthermore, the high weather-resistant and anti-yellowing thermoplastic polyurethane cured product provided by the present invention is used for the film made by lamination processing, which has no crystal points on the appearance, good transparency, and excellent anti-yellowing and weather resistance properties, and has broad application prospects in the field of film products.

[0073] The content disclosed above is only the preferred feasible embodiments of the present invention, and does not limit the claims of the present invention. Therefore, all equivalent technical changes made by using the content of the specification and drawings of the present invention are included in the claims of the present invention.

Claims

1. A highly weather-resistant and anti-yellowing thermoplastic polyurethane cured product, characterized in that: The thermoplastic polyurethane cured product comprises a thermoplastic polyurethane, an ultraviolet absorber and a light stabilizer combination; based on the total weight of the highly weather-resistant and anti-yellowing thermoplastic polyurethane cured product, the content of the thermoplastic polyurethane is 97 wt % to 99 wt %, the content of the ultraviolet absorber is 0.1 wt % to 0.5 wt %, and the content of the light stabilizer combination is 0.3 wt % to 1 wt %; The thermoplastic polyurethane is formed by a reaction composition, the reaction composition comprises an isocyanate component, a polyol component and a diol chain extender component, the polyol component is selected from the group consisting of polyether polyol, polyester polyol and polycaprolactone polyol; The light stabilizer combination is a combination of a phosphorus light stabilizer, a hindered amine light stabilizer and a hindered phenol light stabilizer.

2. The thermoplastic polyurethane cured product according to claim 1, characterized in that: The weight ratio of the phosphorus-based light stabilizer, the hindered amine light stabilizer and the hindered phenol light stabilizer is 1:1.5:

3.

3. The thermoplastic polyurethane cured product according to claim 1, characterized in that: In the reaction composition, relative to 100 parts by weight of the polyol component, the amount of the isocyanate component is 62 parts by weight to 66 parts by weight, and the amount of the diol chain extender component is 13 parts by weight to 15 parts by weight.

4. The thermoplastic polyurethane cured product according to claim 3, characterized in that: The isocyanate component is diphenylmethane diisocyanate.

5. The cured thermoplastic polyurethane according to claim 3, characterized in that: The diol chain extender component is at least one of a linear diol and a branched diol having a number average molecular weight of less than 500 g / mol.

6. The cured thermoplastic polyurethane according to claim 5, characterized in that: The diol chain extender is 1,4-dibutanol.

7. The cured thermoplastic polyurethane according to claim 1, characterized in that: The reaction composition includes stannous octoate as a catalyst, and the amount of the catalyst is 0.04 to 0.06 parts by weight relative to 100 parts by weight of the polyol component.

8. The cured thermoplastic polyurethane according to claim 1, characterized in that: The ultraviolet absorber is at least one of 2-hydroxy-4-methoxybenzophenone and 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole.

9. The cured thermoplastic polyurethane according to claim 1, characterized in that: The phosphorus-based light stabilizer is at least one of tris(2,4-di-tert-butylphenyl)phosphate and tris(2,4-di-tert-butylphenyl)phosphite, the hindered amine light stabilizer is at least one of 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine and poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) ester, and the hindered phenol light stabilizer is 2,2'-methylenebis(6-tert-butyl-4-methylphenol).

10. The cured thermoplastic polyurethane according to claim 1, characterized in that: The polyester polyol is selected from the group consisting of: poly(1,4-butylene adipate), poly(1,4-butylene adipate) and poly(1,4-hexanediol adipate). The polyether polyol is selected from the group consisting of: poly(oxyethylene) glycol, poly(oxypropylene) glycol and poly(oxytetramethylene) glycol.

11. A method for producing a thermoplastic polyurethane cured product with high weather resistance and yellowing resistance, characterized in that: The manufacturing method comprises: A reaction composition, a UV absorber and a light stabilizer combination are added into an extruder for polymerization reaction, wherein the NCO / OH ratio is 0.98 to 1.02, so as to form a thermoplastic polyurethane composition; the reaction composition comprises an isocyanate component, a polyol component and a diol chain extender component, wherein the polyol component is selected from the group consisting of polyether polyol, polyester polyol and polycaprolactone polyol; the light stabilizer combination is a combination of a phosphorus light stabilizer, a hindered amine light stabilizer and a hindered phenol light stabilizer; and The thermoplastic polyurethane composition is extruded and granulated to obtain a plurality of thermoplastic polyurethane cured products with high weather resistance and yellowing resistance; based on the total weight of the thermoplastic polyurethane cured products with high weather resistance and yellowing resistance, the content of the thermoplastic polyurethane is 97 wt % to 99 wt %, the content of the ultraviolet absorber is 0.1 wt % to 0.5 wt %, and the content of the light stabilizer combination is 0.3 wt % to 1 wt %.

Images