Hydrolysis-resistant TPU synthetic leather and preparation method thereof
By adding modified TPU particles and lignin fiber powder to the TPU synthetic leather, a physical barrier and dense mesh structure is formed, the problem of hydrolysis resistance of TPU synthetic leather in humid environments is solved, and its durability and appearance performance are significantly improved.
Patent Information
- Application Number
- CN202510166170.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2025-04-29
AI Technical Summary
TPU synthetic leather is prone to yellowing and surface fall off in humid environments, resulting in reduced durability and limiting its use in certain specific application scenarios.
By adding modified TPU particles prepared with lignin fibers and polyphenylene sulfide fibers as raw materials to the TPU layer, and combining lignin fiber powder as filler, a physical barrier and a denser mesh structure are formed to improve the hydrolysis resistance of TPU synthetic leather.
It significantly improves the hydrolysis resistance and durability of TPU synthetic leather, reduces the occurrence of hydrolysis reactions, improves the appearance texture and feel of the material, and extends the service life.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of synthetic leather, and more specifically, to a hydrolysis-resistant TPU synthetic leather and a preparation method thereof. Background Art
[0002] TPU synthetic leather is a new type of environmentally friendly material. It is made of thermoplastic polyurethane (TPU) through a special process and has excellent wear resistance, tensile strength, elongation, flame retardancy, gasoline resistance, cold resistance and bending resistance. Compared with traditional PVC artificial leather, the production process of TPU synthetic leather is more environmentally friendly and can achieve breathable and semi-breathable effects. It is suitable for a variety of fields such as clothing, furniture, sports goods, military products, automotive interiors and decorative materials.
[0003] In recent years, with the increasing environmental protection requirements, TPU synthetic leather has received more and more attention as an environmentally friendly synthetic leather solution. It can not only be used in high value-added products such as medical supplies, bags, suitcases and sneakers, but also has important significance for promoting sustainable development due to its recyclability.
[0004] With respect to the above-mentioned related technologies, the inventors found that although TPU synthetic leather has good wear resistance, cold resistance and bending resistance, its hydrolysis resistance is poor. It is prone to yellowing and surface peeling in a humid environment, which reduces the overall performance and durability of the material. This limits the use of TPU synthetic leather in certain specific application scenarios. Summary of the invention
[0005] In order to improve the hydrolysis resistance and durability of TPU synthetic leather, the present application provides a hydrolysis-resistant TPU synthetic leather and a preparation method thereof.
[0006] In the first aspect, the present application provides a hydrolysis-resistant TPU synthetic leather, using the following technical solution: A hydrolysis-resistant TPU synthetic leather comprises a base fabric, an adhesive layer and a TPU layer which are sequentially bonded together, wherein the raw materials of the TPU layer comprise 50-70 parts of modified TPU particles, 20-30 parts of silicone resin, 2-8 parts of lignin fiber powder and 3-10 parts of other additives in parts by weight; In parts by weight, the raw materials of the modified TPU particles include 45-50 parts of macromolecular polyol, 12-18 parts of polyisocyanate, 5-15 parts of hydrophobic molecular chain extender and 12-24 parts of composite fiber; The composite fiber comprises lignin fiber and polyphenylene sulfide fiber in a mass ratio of (1-5):(4-8).
[0007] By adopting the above technical scheme, the modified TPU particles prepared with polyisocyanate as raw material have a polycarbodiimide structure, which can effectively neutralize the carboxyl groups generated during the hydrolysis of polyurethane, repair the broken chains in the hydrolyzed polymer, and prevent autocatalytic hydrolysis reactions.
[0008] Lignin fiber has natural hydrophobicity, which can reduce the contact between TPU synthetic leather and water, thereby reducing its water absorption performance. It can form a physical barrier in the TPU layer and form a strong interfacial bonding force with the TPU matrix, which hinders the penetration of water molecules into the TPU. It can significantly enhance the water resistance of TPU synthetic leather and reduce the occurrence of hydrolysis reactions. Lignin powder is added to the TPU substrate as a filler, which can provide more nucleation points for the aggregation of macromolecular coils, promote the orderly arrangement and curing of TPU molecular chains, improve the cohesion effect of the TPU layer, and enhance the hydrolysis resistance of TPU synthetic leather. The addition of lignin fiber powder can also improve the pore structure of the TPU layer, fill uneven areas, improve the softness and smooth defects of synthetic leather materials, and improve the appearance, texture and feel of TPU synthetic leather.
[0009] Polyphenylene sulfide fiber not only has excellent hydrolysis resistance, but also is resistant to acids, alkalis and oxidants, thereby improving the antioxidant capacity of TPU and extending the service life of TPU synthetic leather.
[0010] The two types of fiber composites are added to the modified TPU particles as raw materials and can be mixed with the TPU matrix at the particle level, which can reduce the phenomenon of fiber agglomeration during processing, facilitate processing, and enhance the dispersion uniformity of the composite fibers. The composite use of the two fibers can combine the hydrophobicity and physical barrier effect of lignin fiber and the hydrolysis resistance and chemical stability of polyphenylene sulfide fiber.
[0011] In addition, the addition of composite fibers can affect the microstructure of TPU synthetic leather, optimize the distribution of hard segments and soft segments, enhance the entanglement and cross-linking of molecular chains, thereby forming a denser network structure and further improving the hydrolysis resistance of TPU synthetic leather.
[0012] Optionally, the method for preparing the modified TPU particles comprises the following steps: S1: Mix the macromolecular polyol and the polyisocyanate, heat and stir at 80-100° C. in an inert gas atmosphere, cool to 60-70° C., add a hydrophobic molecular chain extender, and stir to react for 1-1.5 hours to obtain a polyurethane stock solution; S2: pouring the polyurethane stock solution into deionized water and stirring to obtain a polyurethane prepolymer; S3: adding composite fiber to the polyurethane prepolymer, mixing and stirring for 50-60 minutes to obtain a modified TPU stock solution; S4: curing, drying, crushing and granulating the modified TPU stock solution to obtain the modified TPU.
[0013] Optionally, the hydrophobic molecular chain extender is selected from any one or more combinations of 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 4,4-methylenebis(2,6-diethyl)aniline, and 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane.
[0014] By adopting the above technical solution, hydrophobic groups such as ethyl, benzene ring, diphenylmethane, siloxane, etc. can be effectively introduced in the synthesis process of polyurethane to increase the hydrophobicity of TPU molecules, thereby reducing the erosion of TPU by water molecules and significantly improving the hydrolysis resistance.
[0015] Optionally, the other additives include a thickener, a flame retardant and an antioxidant in a mass ratio of (1.5-2.5):(0.5-1):(2-3).
[0016] By adopting the above technical solution, the flame retardant and antioxidant properties of TPU synthetic leather can be further improved.
[0017] Optionally, the antioxidant is selected from any one of antioxidant 168, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098 or antioxidant 3114.
[0018] By adopting the above technical scheme, antioxidant 168, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098 and antioxidant 3114 all have good antioxidant properties, can capture free radicals generated by TPU synthetic leather materials during processing and use, decompose hydroperoxides, slow down the oxidation of materials, and help improve the durability of TPU synthetic leather.
[0019] Optionally, the base fabric is a polylactic acid non-woven fabric.
[0020] By adopting the above technical solution, the polylactic acid non-woven fabric has good plasticity and hydrolysis resistance, can better block moisture, maintain the structural and functional integrity of the TPU synthetic leather, and extend its service life.
[0021] Optionally, the raw materials of the bonding layer include 80-100 parts of water-based resin, 0.8-1 parts of leveling agent, 0.05-0.1 parts of defoaming agent, 4-6 parts of thickener and 8-10 parts of cross-linking agent in parts by weight.
[0022] By adopting the above technical solution, the water-based resin, leveling agent, defoamer, thickener and cross-linking agent in the bonding layer can maximize the bonding strength and hydrolysis resistance of the bonding layer under this ratio, thereby ensuring the durability and stability of the TPU synthetic leather.
[0023] In a second aspect, the present application provides a method for preparing a hydrolysis-resistant TPU synthetic leather, which adopts the following technical scheme: A method for preparing a hydrolysis-resistant TPU synthetic leather, comprising the following steps: The components of the adhesive layer are mixed to obtain a mixed solution, the mixed solution is applied to the surface of the base fabric by a printing process, and a catalytic reaction is carried out at 130-150° C. for 1-3 minutes to obtain a semi-cured base fabric; Mix the silicone resin, modified TPU particles, lignin fiber powder and other additives, and stir at a constant temperature of 80-90° C. for 2-4 hours to obtain a blend; The blend is formed on a release paper by extrusion casting to obtain a cast film to form a TPU layer; The side of the TPU layer away from the release paper is laminated to the semi-cured base fabric, and the release paper is separated after curing to obtain the product.
[0024] By adopting the above technical solution, the mixing, coating, curing and bonding of each component in the entire preparation process can be accurately controlled to obtain high-quality hydrolysis-resistant TPU synthetic leather, ensuring the close bonding of the TPU layer and the semi-cured base fabric. The process is simple and easy to scale up.
[0025] Optionally, the release paper is TPX type release paper.
[0026] By adopting the above technical solution, the TPX release paper has high heat resistance and is easy to peel off, can remain stable in high-temperature processes, can be easily separated, and will not remain on the surface of the TPU layer.
[0027] Optionally, the lamination pressure of the TPU layer and the semi-cured base fabric is 10-15 kgf / cm 2 The bonding temperature is 170-190℃.
[0028] By adopting the above technical solution, the bonding between the TPU layer and the semi-cured base fabric can be promoted during the bonding process, thereby enhancing the hydrolysis resistance and mechanical strength of the TPU synthetic leather.
[0029] In summary, this application has the following beneficial effects: 1. The present application adds modified TPU particles prepared with lignin fiber and polyphenylene sulfide fiber as raw materials to the TPU layer, combining the excellent hydrophobicity of lignin fiber and the excellent hydrolysis resistance and chemical stability of polyphenylene sulfide fiber. The two are mixed with the TPU substrate at the particle level, which can effectively enhance the dispersion uniformity of the composite fiber in the TPU layer, form a physical barrier in the TPU layer, and form a denser network structure in the TPU layer, effectively improving the hydrolysis resistance of the TPU synthetic leather.
[0030] 2. The present application adds lignin fiber powder as filler in the TPU layer, which can not only provide more nucleation points for the aggregation of macromolecular coils, improve the cohesion effect of the TPU layer to enhance the hydrolysis resistance of the TPU synthetic leather, but also improve the appearance texture and softness of the TPU synthetic leather.
[0031] 3. In the preparation method of the present application, hydrophobic groups are effectively introduced into the polyurethane molecules to increase the hydrophobicity of the TPU molecules, thereby reducing the erosion of the TPU by water molecules, which can effectively improve the hydrolysis resistance of the TPU synthetic leather. It has the advantages of simple process flow, high processing efficiency and easy operation, and is helpful to form a good appearance and texture of synthetic leather. DETAILED DESCRIPTION
[0032] The following examples further illustrate the present application in detail.
[0033] raw material Unless otherwise specified, the raw materials used in the preparation examples, embodiments and comparative examples in this application are all commercially available products, specifically: The organic silicon resin is methylphenyl silicon resin, selected from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., with the product number of lnb-1519806; Lignin fiber, selected from Juke Technology Co., Ltd., length 6mm, density 0.92kg / m 3 ;; Lignin fiber powder is prepared by mechanical grinding of lignin fiber, with a mesh size of 60 meshes; The macromolecular polyol is polytetramethylene ether glycol, which is selected from Hyosung Chemical Co., Ltd. and has an average molecular weight of 2000; The polyisocyanate was toluene diisocyanate, selected from Shanghai Yuanye Biotechnology Co., Ltd., T135411; Polyphenylene sulfide fiber, selected from Deyang Keji High-tech Materials Co., Ltd., PPS short fiber, length 38-80mm; Thickener, which is a polyurethane associative thickener, selected from Anhui Feimiao Chemical Co., Ltd., with a product number of N-140; Flame retardant, selected from Dongguan Chenwei New Material Technology Co., Ltd., 20240411BDMMP; Antioxidant 168, antioxidant 1010, antioxidant 1076, all selected from Kangjin Chemical, industrial grade antioxidant 168, 1010, 1076; water-based resin, polyester-type water-based polyurethane resin, selected from Anhui Feimiao Chemical Co., Ltd., item number FS-1930C; Leveling agent, which is an organic silicon leveling agent, selected from Guangzhou Dachuan Fine Chemical Co., Ltd., BYK-301; Defoamer, which is a silicone defoamer, selected from Dongguan Defeng Defoamer Co., Ltd., DF-2854; The cross-linking agent is a blocked water-based isocyanate cross-linking agent with a viscosity of 1000-3000 mpa·s; The release paper is TPX type release paper, brand DX820.
[0034] Preparation Examples 1.1-1.7 of Modified TPU Particles Preparation Example 1.1 The modified TPU particles and the amounts of the raw materials are shown in Table 1, wherein the hydrophobic molecular chain extender is 3,3'-dichloro-4,4'-diphenylmethanediamine, and the composite fiber includes lignin fiber and polyphenylene sulfide fiber in a mass ratio of 1:4.
[0035] Table 1 The preparation method of the above-mentioned modified TPU particles comprises the following steps: S1: Mix the macromolecular polyol and the polyisocyanate, heat and stir at 80°C in an inert gas atmosphere, cool to 60°C, add a hydrophobic molecular chain extender, stir and react for 1 hour to obtain a polyurethane stock solution; S2: Pour the polyurethane stock solution into 50L of deionized water and stir it in a high-speed stirrer at a speed of 8000rmp for 1h to obtain a polyurethane prepolymer; S3: adding composite fiber to the polyurethane prepolymer, mixing and stirring for 60 min at a speed of 1500 rpm in a high-speed stirrer to obtain a modified TPU stock solution; S4: curing, drying, crushing and granulating the modified TPU stock solution to obtain the modified TPU.
[0036] Preparation Example 1.2 The modified TPU particles, the amounts of each raw material are shown in Table 1, wherein the hydrophobic molecular chain extender is 3,5-dimethylthiotoluenediamine, the composite fiber comprises lignin fiber and polyphenylene sulfide fiber in a mass ratio of 3:5, and the preparation method of the modified TPU particles comprises the following steps: S1: Mix the macromolecular polyol and the polyisocyanate, heat and stir at 100°C in an inert gas atmosphere, cool to 70°C, add a hydrophobic molecular chain extender, stir and react for 1.5 hours to obtain a polyurethane stock solution; S2: Pour the polyurethane stock solution into 50L of deionized water and stir it in a high-speed stirrer at a speed of 8000rmp for 1h to obtain a polyurethane prepolymer; S3: adding composite fiber to the polyurethane prepolymer, mixing and stirring at a speed of 1500 rpm in a high-speed stirrer for 50 min to obtain a modified TPU stock solution; S4: curing, drying, crushing and granulating the modified TPU stock solution to obtain the modified TPU.
[0037] Preparation Example 1.3 The modified TPU particles, the amounts of each raw material are shown in Table 1, wherein the hydrophobic molecular chain extender is 3,5-diethyltoluenediamine, the composite fiber comprises lignin fiber and polyphenylene sulfide fiber in a mass ratio of 4:7, and the preparation method of the modified TPU particles comprises the following steps: S1: Mix the macromolecular polyol and the polyisocyanate, heat and stir at 90°C in an inert gas atmosphere, cool to 65°C, add a hydrophobic molecular chain extender, and stir to react for 1.5 hours to obtain a polyurethane stock solution; S2: Pour the polyurethane stock solution into 50L of deionized water and stir it in a high-speed stirrer at a speed of 8000rmp for 1h to obtain a polyurethane prepolymer; S3: adding composite fiber to the polyurethane prepolymer, mixing and stirring for 60 min at a speed of 1500 rpm in a high-speed stirrer to obtain a modified TPU stock solution; S4: curing, drying, crushing and granulating the modified TPU stock solution to obtain the modified TPU.
[0038] Preparation Example 1.4 The modified TPU particles are different from those in Preparation Example 1 in that the amounts of the raw materials are as shown in Table 1, wherein the hydrophobic molecular chain extender is 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane, the composite fiber comprises lignin fiber and polyphenylene sulfide fiber in a mass ratio of 5:8, and the other steps are the same as those in Preparation Example 1.
[0039] Preparation Example 1.5 The modified TPU particles are different from those in Preparation Example 1 in that no lignin fiber is added, the lignin fiber in the raw composite fiber is replaced with polyphenylene sulfide fiber of equal mass, and the other steps are the same as those in Preparation Example 1.
[0040] Preparation Example 1.6 The modified TPU particles are different from those in Preparation Example 1 in that no polyphenylene sulfide fiber is added, the polyphenylene sulfide fiber in the raw composite fiber is replaced with lignin fiber of equal mass, and the other steps are the same as those in Preparation Example 1.
[0041] Preparation Example 1.7 The modified TPU particles are different from those in Preparation Example 1 in that no composite fiber is added, and the other steps are the same as those in Preparation Example 1.
[0042] Preparation Examples 2.1-2.3 of Semi-cured Base Fabric Preparation Example 2.1 The semi-cured base fabric comprises a base fabric and a bonding layer. The raw materials and amounts thereof are shown in Table 2, wherein the base fabric is a polylactic acid non-woven fabric.
[0043] Table 2 The preparation method of the semi-cured base fabric comprises the following steps: S1: cleaning the base fabric and drying it to obtain a pretreated base fabric; S2: mixing and stirring the water-based resin, leveling agent, defoamer, thickener and cross-linking agent to obtain a mixed solution; S3: Using a printing process, the pretreated base fabric is fed with a mesh roller, the mixed liquid is coated on the surface of the base fabric, and then placed in an oven for baking. The temperature is set to 150° C. and the operating speed is 30 m / min for a high-temperature catalytic reaction for 1 minute. The thickness of the adhesive layer is 0.1 mm.
[0044] Preparation Example 2.2 The semi-cured base fabric is different from the preparation example 2.1 in that the raw materials and amounts are as shown in Table 2. The preparation method thereof comprises the following steps: S1: cleaning the base fabric and drying it to obtain a pretreated base fabric; S2: mixing and stirring the water-based resin, leveling agent, defoamer, thickener and cross-linking agent to obtain a mixed solution; S3: Using a printing process, the pretreated base fabric is fed with a mesh roller, the mixed liquid is coated on the surface of the base fabric, and then placed in an oven for baking. The temperature is set to 130°C and the operating speed is 30m / min for a high-temperature catalytic reaction for 3min, and the thickness of the adhesive layer is 0.1mm.
[0045] Preparation Example 2.3 The semi-cured base fabric is different from the preparation example 2.1 in that the raw materials and amounts are as shown in Table 2. The preparation method thereof comprises the following steps: S1: cleaning the base fabric and drying it to obtain a pretreated base fabric; S2: mixing and stirring the water-based resin, leveling agent, defoamer, thickener and cross-linking agent to obtain a mixed solution; S3: Using a printing process, the pretreated base fabric is fed with a mesh roller, the mixed liquid is coated on the surface of the base fabric, and then placed in an oven for baking. The temperature is set to 140°C and the operating speed is 30m / min for high-temperature catalytic reaction for 2min, and the thickness of the adhesive layer is 0.1mm. Example
[0046] Example 1 A hydrolysis-resistant TPU synthetic leather, wherein the raw materials and amounts are shown in Table 3, wherein other additives include a thickener, a flame retardant and an antioxidant in a mass ratio of 1.5:0.5:2, the antioxidant is antioxidant 168, the modified TPU particles are prepared by Preparation Example 1.1, the semi-cured base fabric is prepared by Preparation Example 2.1, and the release paper is TPX type release paper.
[0047] Table 3 Example 1 Example 2 Example 3 Example 4 Modified TPU particles / Kg 60 50 70 60 Silicone resin / Kg 25 20 25 30 Lignin fiber powder / Kg 6 2 8 6 Other additives / Kg 5 3 10 7 The method for preparing the hydrolysis-resistant TPU synthetic leather comprises the following steps: S1: Mixing silicone resin, modified TPU particles, lignin fiber powder and other additives, and stirring at a constant temperature of 90° C. for 2 h to obtain a blend; S2: The temperature of the barrel, filter screen, elbow, connection and die head are all set to 170°C, the film cast from the die head is attached to the forming roller at a height of 8mm, the thickness is controlled to be 2mm, the blend is added to the casting machine for extrusion casting and formed on the release paper to obtain a cast film to form a TPU layer; S3: Set the lamination pressure to 10kgf / cm 2 The laminating temperature is 190°C, and the side of the TPU layer away from the release paper is laminated to the semi-cured base cloth. After aging at 80°C for 24 hours, the release paper is separated to obtain the product.
[0048] Example 2 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the raw materials and amounts are as shown in Table 3, wherein other additives include a thickener, a flame retardant and an antioxidant in a mass ratio of 2:1:2.5, the antioxidant is antioxidant 1010, and the semi-cured base fabric is prepared by Preparation Example 2.2; The method for preparing the hydrolysis-resistant TPU synthetic leather comprises the following steps: S1: Mixing silicone resin, modified TPU particles, lignin fiber powder and other additives, and stirring at a constant temperature of 80° C. for 4 h to obtain a blend; S2: The temperature of the barrel, filter screen, elbow, connection and die head are all set to 170°C, the film cast from the die head is attached to the forming roller at a height of 8mm, the thickness is controlled to be 2mm, the blend is added to the casting machine for extrusion casting and formed on the release paper to obtain a cast film to form a TPU layer; S3: Set the lamination pressure to 15kgf / cm 2 The bonding temperature is 170°C, and the side of the TPU layer away from the release paper is bonded to the semi-cured base cloth. After aging at 80°C for 24 hours, the release paper is separated to obtain the product.
[0049] Example 3 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the raw materials and amounts are as shown in Table 3, wherein other additives include a thickener, a flame retardant and an antioxidant in a mass ratio of 2.5:0.5:3, the antioxidant is antioxidant 1076, and the semi-cured base fabric is prepared by Preparation Example 2.3; The method for preparing the hydrolysis-resistant TPU synthetic leather comprises the following steps: S1: Mixing silicone resin, modified TPU particles, lignin fiber powder and other additives, and stirring at a constant temperature of 90° C. for 2.5 h to obtain a blend; S2: The temperature of the barrel, filter screen, elbow, connection and die head are all set to 170°C, the film cast from the die head is attached to the forming roller at a height of 8mm, the thickness is controlled to be 2mm, the blend is added to the casting machine for extrusion casting and formed on the release paper to obtain a cast film to form a TPU layer; S3: Set the lamination pressure to 10kgf / cm 2 The bonding temperature is 180°C, and the side of the TPU layer away from the release paper is bonded to the semi-cured base cloth. After aging at 80°C for 24 hours, the release paper is separated to obtain the product.
[0050] Example 4 A hydrolysis-resistant TPU synthetic leather is different from Example 1 in that the raw materials and amounts are as shown in Table 3, and the other steps are the same as those in Example 1.
[0051] Example 5 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.2, and the other steps are the same as Example 1.
[0052] Example 6 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.3, and the other steps are the same as Example 1.
[0053] Example 7 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.4, and the other steps are the same as Example 1.
[0054] Comparative Example Comparative Example 1 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.5, and the other steps are the same as Example 1.
[0055] Comparative Example 2 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.6, and the other steps are the same as Example 1.
[0056] Comparative Example 3 A hydrolysis-resistant TPU synthetic leather, which is different from Example 1 in that the modified TPU particles in the raw material are prepared by Preparation Example 1.7, and the other steps are the same as Example 1.
[0057] Comparative Example 4 A hydrolysis-resistant TPU synthetic leather is different from Example 1 in that no lignin fiber powder is added to the raw material, the lignin fiber powder in the raw material is replaced by an equal mass of silicone resin, and the other steps are the same as those in Example 1.
[0058] Comparative Example 5 A hydrolysis-resistant TPU synthetic leather, which differs from Example 1 in that modified TPU particles and lignin fiber powder are not added to the raw materials, the original modified TPU particles are replaced by ordinary TPU particles, and the lignin fiber powder is replaced by an organosilicon resin of equal mass, which is originally selected from Suzhou Longou Plastic Chemical Co., Ltd. with a product number of 1180A, and the other steps are the same as those in Example 1.
[0059] Performance testing The hydrolysis-resistant TPU synthetic leathers prepared in Examples 1-7 and Comparative Examples 1-5 were tested for surface skin feel, hydrolysis resistance and hydrolysis resistance performance.
[0060] 1. Surface skin feel test: 20 volunteers with normal sense organs were selected to conduct surface skin feel tests on the hydrolysis-resistant TPU synthetic leathers prepared in Examples 1-7 and Comparative Examples 1-5, respectively. Scores were given based on a full score of 100, and the final average score was calculated and recorded in Table 4; The scoring criteria are as follows: ≤60 points: rough surface, poor gloss, obvious rough friction, uneven texture distribution, hard feel, and poor resilience; 60-80 points: the surface is relatively smooth, the glossiness is average, there is a slight roughness, the texture is evenly distributed, the feel is relatively soft, and the resilience is average; 80-100 points: the surface is flat and smooth, with good gloss, no roughness or friction, uniform texture distribution, soft and uniform feel, and good resilience.
[0061] 2. Hydrolysis resistance test: Cut each group of samples into synthetic leather samples of 25mm×25mm in size, hang them in a constant temperature and humidity chamber for humid heat aging, the constant temperature and humidity are 70±2℃, the relative humidity is above 95%, and the humid heat treatment is 21d; The peel strength of the samples was tested before and after the hydrolysis resistance test according to GB2792 standard, and the retention rate of the peel strength was calculated. Each group of experiments was conducted 3 times, and the average value was recorded in Table 4.
[0062] Table 4 It can be seen from the performance test results in Table 4 that the TPU synthetic leather prepared by the preparation method of the present application has excellent hydrolysis resistance, and the peel strength after 21 days of hot tide treatment can still maintain more than 97.8%.
[0063] According to the performance test results of Examples 1-6, Comparative Examples 1-3 and Comparative Example 5, it can be seen that compared with the TPU synthetic leather prepared by ordinary TPU particles, the modified TPU particles prepared by adding lignin fiber and polyphenylene sulfide fiber as raw materials to the TPU layer of the present application can significantly improve the hydrolysis resistance of the TPU synthetic leather and improve the durability of the TPU synthetic leather. The composite use of lignin fiber and polyphenylene sulfide fiber can combine the excellent hydrophobicity of lignin fiber and the excellent hydrolysis resistance and chemical stability of polyphenylene sulfide fiber to form a physical barrier in the TPU layer and form a denser mesh structure. Compared with the use of a single fiber, it can more effectively improve the hydrolysis resistance of the TPU synthetic leather.
[0064] It can be seen from the performance test results of Examples 1-6 and Comparative Examples 4-5 that adding lignin fiber powder as a filler in the TPU layer can not only provide more nucleation points for the aggregation of macromolecular coils, improve the cohesion effect of the TPU layer to enhance the hydrolysis resistance of the TPU synthetic leather, but also improve the appearance texture and softness of the TPU synthetic leather, and enhance the appearance and skin feel of the TPU synthetic leather.
[0065] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A hydrolysis-resistant TPU synthetic leather, comprising a base fabric, an adhesive layer and a TPU layer laminated together in sequence, characterized in that: In parts by weight, the raw materials of the TPU layer include 50-70 parts of modified TPU particles, 20-30 parts of silicone resin, 2-8 parts of lignin fiber powder and 3-10 parts of other additives; In parts by weight, the raw materials of the modified TPU particles include 45-50 parts of macromolecular polyol, 12-18 parts of polyisocyanate, 5-15 parts of hydrophobic molecular chain extender and 12-24 parts of composite fiber; The composite fiber comprises lignin fiber and polyphenylene sulfide fiber in a mass ratio of (1-5):(4-8).
2. The hydrolysis-resistant TPU synthetic leather according to claim 1, characterized in that: The preparation method of the modified TPU particles comprises the following steps: S1: Mix the macromolecular polyol and the polyisocyanate, heat and stir at 80-100° C. in an inert gas atmosphere, cool to 60-70° C., add a hydrophobic molecular chain extender, and stir to react for 1-1.5 hours to obtain a polyurethane stock solution; S2: pouring the polyurethane stock solution into deionized water and stirring to obtain a polyurethane prepolymer; S3: adding composite fiber to the polyurethane prepolymer, mixing and stirring for 50-60 minutes to obtain a modified TPU stock solution; S4: curing, drying, crushing and granulating the modified TPU stock solution to obtain.
3. The hydrolysis-resistant TPU synthetic leather according to claim 1, characterized in that: The hydrophobic molecular chain extender is selected from any one or more combinations of 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-dimethylthiotoluenediamine, 3,5-diethyltoluenediamine, 4,4-methylenebis(2,6-diethyl)aniline, and 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane.
4. The hydrolysis-resistant TPU synthetic leather according to claim 1, characterized in that: The other additives include a thickener, a flame retardant and an antioxidant in a mass ratio of (1.5-2.5):(0.5-1):(2-3).
5. The hydrolysis-resistant TPU synthetic leather according to claim 4, characterized in that: The antioxidant is selected from any one of antioxidant 168, antioxidant 1010, antioxidant 1035, antioxidant 1076, antioxidant 1098 or antioxidant 3114.
6. The hydrolysis-resistant TPU synthetic leather according to claim 1, characterized in that: The base fabric is a polylactic acid non-woven fabric.
7. The hydrolysis-resistant TPU synthetic leather according to claim 1, characterized in that: In parts by weight, the raw materials of the bonding layer include 80-100 parts of water-based resin, 0.8-1 parts of leveling agent, 0.05-0.1 parts of defoaming agent, 4-6 parts of thickener and 8-10 parts of cross-linking agent.
8. The method for preparing a hydrolysis-resistant TPU synthetic leather according to any one of claims 1 to 7, characterized in that: The following steps are involved: The components of the adhesive layer are mixed to obtain a mixed solution, the mixed solution is applied to the surface of the base fabric by a printing process, and a catalytic reaction is carried out at 130-150° C. for 1-3 minutes to obtain a semi-cured base fabric; Mix the silicone resin, modified TPU particles, lignin fiber powder and other additives, and stir at a constant temperature of 80-90° C. for 2-4 hours to obtain a blend; The blend is formed on a release paper by extrusion casting to obtain a cast film to form a TPU layer; The side of the TPU layer away from the release paper is laminated to the semi-cured base fabric, and the release paper is separated after curing to obtain the product.
9. The method for preparing the hydrolysis-resistant TPU synthetic leather according to claim 8, characterized in that: The release paper is TPX type release paper.
10. The method for preparing hydrolysis-resistant TPU synthetic leather according to claim 8, characterized in that: The lamination pressure when the TPU layer and the semi-cured base fabric are laminated is 10-15 kgf / cm 2 The bonding temperature is 170-190℃.