A thermoplastic silicone elastomer foamed skin composite and a method of making the same

Abstract

The application relates to a thermoplastic silicone elastomer foamed skin composite material and a preparation method thereof, which comprises a base cloth layer, a foamed skin layer and a surface coating layer which are sequentially stacked; wherein the foamed skin layer is a microporous elastomer layer foamed by a supercritical fluid and comprises the following components in parts by weight: 70-90 parts of polycarbon type thermoplastic polyurethane, 10-30 parts of a silicone-based elastomer, 1-4 parts of an additive and 0.5-2 parts of a composite compatibilizer, wherein the composite compatibilizer comprises amino-terminated polysiloxane, polyester type thermoplastic polyurethane grafted polysiloxane copolymer and fluorine-containing alkyl polysiloxane. The application introduces the composite compatibilizer composed of amino-terminated polysiloxane, polyester type thermoplastic polyurethane grafted polysolxane copolymer and fluorine-containing alkyl polysiloxane into the foamed skin layer, builds a multiple protection structure from the interface to the surface in the foamed skin layer, changes the surface protection of the composite material into overall protection and significantly enhances the overall solvent resistance of the material.

Description

Technical Field

[0001] This application relates to the field of automotive interior materials technology, and in particular to a thermoplastic silicone elastomer foamed skin composite material and its preparation method. Background Technology

[0002] To meet increasingly stringent environmental regulations and in-vehicle air quality standards, thermoplastic elastomers have gained widespread attention due to their low VOC (volatile organic compound) emissions, excellent weather resistance, and soft touch. However, existing thermoplastic elastomer foam materials used in automotive interiors still face a series of technical bottlenecks in practical applications. For example, the automotive interior environment is a complex system of coexisting chemical media. Interior materials frequently come into contact with various organic solvents and chemicals during daily use, including: ① cleaning wipes and sprays containing organic solvents such as ethanol and isopropanol used during vehicle interior cleaning and maintenance; ② personal care products such as sunscreen, hand cream, and cosmetics left by passengers, which typically contain esters, silicone oils, and various organic solvents; ③ accidental food stains, beverages containing terpenes, and gasoline components formed by the condensation of fuel volatiles. The organic solvents listed above have significant swelling, dissolving, or extracting effects on polymer materials, making thermoplastic elastomers susceptible to chemical corrosion.

[0003] To address the aforementioned issues, traditional solutions typically employ a protective coating to isolate chemical media. For example, Chinese patent CN217515099U discloses a stain-resistant automotive interior component that combines a protective coating with a multi-layered undercoating, effectively preventing water and dirt from adhering to the interior surface. However, this technology primarily targets protection against conventional water-based stains. The long-term resistance of its coating system to organic solvents such as alcohols and esters remains unclear, and the adhesion between the coating and the elastomer substrate is prone to failure under prolonged use and repeated solvent wiping. More critically, once the coating is partially damaged, the underlying foamed material will be directly exposed to the solvent environment. Due to the porous structure of the foamed material, which significantly increases the specific surface area, the solvent will rapidly penetrate into the material through capillary action, leading to irreversible structural damage and performance degradation.

[0004] Therefore, developing a foamed composite material for automotive interior trim that can form an integrated solvent-resistant protection system from the material itself to the surface coating, with strong interfacial bonding between each layer and excellent comprehensive physical properties, is of great practical significance for improving the service life, aesthetics, and environmental performance of automotive interior parts. Summary of the Invention

[0005] To improve the solvent resistance of foamed skin for automotive interiors, this application provides a thermoplastic silicone elastomer foamed skin composite material and its preparation method.

[0006] In a first aspect, this application provides a thermoplastic silicone elastomer foamed skin composite material, which adopts the following technical solution: A thermoplastic silicone elastomer foamed skin composite material, characterized in that it comprises a base fabric layer, a foamed skin layer and a surface coating layer stacked sequentially. The foamed skin layer is a microporous elastomer layer foamed by supercritical fluid, comprising the following components in parts by weight: 70-90 parts of polycarbonate thermoplastic polyurethane, 10-30 parts of silicone elastomer, 1-4 parts of additives, and 0.5-2 parts of composite compatibilizer. The composite compatibilizer includes amino-terminated polysiloxane, polyester thermoplastic polyurethane grafted polysiloxane copolymer, and fluorinated alkyl polysiloxane. The surface coating comprises a double-layer coating structure of a topcoat and a basecoat; the topcoat comprises the following components in parts by weight: 60-80 parts of silicone resin, 5-10 parts of nano-silica, 5-10 parts of organosilicon wear-resistant additive, 3-5 parts of perfluoroalkyl compound, and 5-15 parts of carbodiimide crosslinking agent; the basecoat comprises chlorinated polyolefin.

[0007] The inventors discovered that by introducing a composite compatibilizer composed of amino-terminated polysiloxane, polyester-type thermoplastic polyurethane grafted polysiloxane copolymer, and fluorinated alkyl polysiloxane into the foamed skin layer, the compatibility between polycarbonate thermoplastic polyurethane and silicone-based elastomer can be significantly improved, thereby endowing the foamed skin layer with excellent intrinsic solvent resistance.

[0008] Specifically, industrially produced thermoplastic polyurethanes (including polycarbonate polyurethanes) typically retain trace amounts of unreacted isocyanate groups during synthesis. This is necessary for process control and also provides reactive sites for subsequent processing. Under the high-temperature conditions of melt blending, the amino groups at the ends of the amino-terminated polysiloxane molecular chains can chemically react with these residual isocyanate groups to form stable urea bonds, thereby chemically anchoring the polysiloxane segments to the surface of the polyurethane phase region. Simultaneously, even with limited reaction, the polysiloxane segments can also be physically anchored to the silicon-based elastomer through molecular chain entanglement. This dual chemical and physical anchoring mechanism lays the foundation for the subsequent construction of the interface structure.

[0009] Building upon this foundation, polyester-type thermoplastic polyurethane grafted polysiloxane copolymers act as "molecular bridges": their polyurethane backbone exhibits good compatibility with the matrix polycarbonate polyurethane, allowing them to integrate into the polyurethane phase region through molecular chain entanglement; their polysiloxane side chains are entangled with amino-terminated polysiloxane segments anchored on the polyurethane surface, while also being compatible with the silicone-based elastomer. Through this backbone integration and side-chain interconnection, the polyurethane phase and the silicone-based elastomer phase are tightly linked, forming a thick and stable interfacial transition layer that effectively blocks the penetration of organic solvents along the interface.

[0010] Meanwhile, fluorinated alkyl polysiloxanes, due to the extremely low surface energy of their fluorinated segments, spontaneously migrate to the material surface during melt processing, forming a fluorine-rich layer on the skin layer, further reducing the material's surface energy. This gradient distribution structure gives the material a microscopic appearance of surface fluorine-rich, interface silicon-rich, and overall cross-linked characteristics, significantly enhancing the overall solvent resistance of the composite material.

[0011] Through the synergistic effect of the three compatibilizers mentioned above, this application constructs a multi-layered protective structure from the interface to the surface within the foamed skin layer. Even if the surface coating suffers minor scratches or localized damage during use, the foamed skin layer itself can still effectively resist the erosion of organic solvents, avoiding the problem of rapid deterioration of traditional materials due to coating failure, thus achieving a leap from surface protection to overall protection.

[0012] In one specific implementation, the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer is modified with a silane coupling agent, wherein the silane coupling agent is KH-560.

[0013] Through further experiments, the inventors discovered that modifying polyester-type thermoplastic polyurethane grafted polysiloxane copolymers with silane coupling agents can enhance the interfacial bonding strength to a new level. Considering the limited number of residual isocyanate groups available for reaction on the main chain of polycarbonate-type thermoplastic polyurethane, this application preferably uses the epoxy silane coupling agent KH-560 for modification.

[0014] The alkoxy group at one end of KH-560 can undergo a hydrolytic condensation reaction with the polysiloxane segment, thereby chemically linking KH-560 to the polysiloxane side chain of the graft copolymer; the epoxy group at the other end is retained at the end of the side chain, becoming the active site for subsequent reactions. During melt blending, the epoxy group can undergo a ring-opening addition reaction with the amino groups at the ends of the amino-terminated polysiloxanes in the composite compatibilization system that have not reacted with the isocyanate groups, forming stable chemical bonds. This achieves chemical bonding with the amino-terminated polysiloxanes, making the compatibilization system more compact and further enhancing the interfacial stability and solvent resistance of the foamed skin layer.

[0015] In one specific implementation, the weight ratio of the amino-terminated polysiloxane, the silane coupling agent-modified polyester thermoplastic polyurethane grafted polysiloxane copolymer, and the fluorinated alkyl polysiloxane is 1:(1.5-5):(0.3-1.5).

[0016] Through extensive experimentation, the inventors verified that the weight ratio of amino-terminated polysiloxane, silane coupling agent-modified polyester-type polyurethane grafted polysiloxane copolymer, and fluorinated alkyl polysiloxane must be controlled within the range of 1:(1.5-5):(0.3-1.5) for the foamed skin layer to form a stable gradient structure, thereby exhibiting excellent intrinsic solvent resistance. If the ratio of the three components exceeds this range, the integrity and synergistic effect of the gradient structure will be compromised, specifically manifested as follows: Excessive addition of amino-terminated polysiloxanes can lead to an excessive number of anchoring points at the interface, resulting in insufficient bridging. The surface of the polyurethane phase region becomes covered by overly dense polysiloxane segments, forming a thick polysiloxane-rich layer. This hinders the physical entanglement between the polyurethane backbone and the matrix polyurethane in the silane-coupled polyester polyurethane grafted polysiloxane copolymer, making it difficult for the bridging effect of the silane-coupled polyester polyurethane grafted polysiloxane copolymer to be fully utilized. Furthermore, the excessively thick polysiloxane layer itself becomes a weak area at the interface, which is prone to intralayer destruction under the action of solvents, thus reducing interfacial stability.

[0017] If an excessive amount of silane coupling agent-modified polyester-polyurethane grafted polysiloxane copolymer is added, it will lead to an excess of bridging material and insufficient anchoring points. While the polyurethane backbone of a large amount of silane coupling agent-modified polyester-polyurethane grafted polysiloxane copolymer can integrate into the matrix polyurethane phase, its polysiloxane side chains remain suspended due to a lack of sufficient amino-terminated polysiloxane to entangle with, failing to effectively connect to the silicon-based elastomer phase. These underutilized silane coupling agent-modified polyester-polyurethane grafted polysiloxane copolymers may aggregate to form micro-clusters, becoming new stress concentration points and solvent penetration channels.

[0018] Excessive addition of fluorinated alkyl polysiloxanes can lead to excessive surface enrichment and weakened interfacial bonding. An excessively thick fluorinated layer on the surface results in two problems: firstly, it lowers the surface energy of the material, affecting the wetting and adhesion of subsequent surface coatings, leading to poor bonding between the coating and the foamed skin layer; secondly, the migration of a large amount of fluorinated alkyl polysiloxanes to the surface reduces their concentration in the interfacial region, weakening the reaction and entanglement between them and amino-terminated polysiloxanes and silane coupling agent-modified polyester-type polyurethane grafted polysiloxane copolymers. This causes defects in the originally dense chemical network, resulting in a decrease in overall solvent resistance instead of an increase.

[0019] In one specific feasible embodiment, the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer is prepared as follows: S1-1, Prepolymer Synthesis: Under nitrogen protection, polybutylene adipate diol and diphenylmethane diisocyanate are added to DMF to react and prepare a prepolymer solution; S2-1, Chain extension reaction: Dissolve 1,4-butanediol in DMF and add it to the prepolymer solution obtained in step S1-1 to react and obtain the chain-extended thermoplastic polyurethane prepolymer solution. S3-1 Grafting reaction: Add mono-amino-terminated polydimethylsiloxane and catalyst to the chain-extended thermoplastic polyurethane prepolymer solution obtained in step S2-1, and then react to obtain the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer.

[0020] By employing the aforementioned multi-step reaction process, a polyester-type thermoplastic polyurethane-grafted polysiloxane copolymer with a high grafting rate and a well-defined structure can be obtained. This copolymer exhibits a clear molecular configuration: a polyester-type thermoplastic polyurethane as the main chain backbone, with polysiloxanes grafted onto the main chain as side chains. This well-defined and regular "main chain-side chain" structure allows it to fully function as a "molecular bridge" in composite compatibilization systems.

[0021] In one specific implementation, the adjuvant includes an anti-migration antioxidant and an anti-migration ultraviolet absorber; more preferably, the anti-migration antioxidant is a hindered amine antioxidant.

[0022] By employing the aforementioned additives in the preparation of the foamed skin layer, the problem of traditional additives being easily extracted and precipitated in organic solvent environments is solved. Anti-migration hindered amine antioxidants and anti-migration ultraviolet absorbers, through high molecular weighting or the introduction of reactive groups, are made less prone to migration within the material. This ensures that the material maintains good anti-aging and anti-ultraviolet properties even after long-term use and repeated solvent contact.

[0023] In one specific implementation, the silicone resin is a fluorine-modified silicone resin.

[0024] While ordinary silicone resins offer some stain resistance, their relatively high surface energy limits their ability to block organic solvents. This application utilizes fluorinated silicone resins, introducing fluorine into the main or side chains of the resin molecules through chemical bonding. This allows the resin to retain the original advantages of silicone resins while further acquiring the low surface energy characteristics unique to fluorinated materials.

[0025] In the topcoat system, fluorinated silicone resin and perfluoroalkyl compounds in the formulation form a "double fluorination effect": the fluorinated silicone resin, as the film-forming host, has chemically bonded fluorine atoms uniformly distributed throughout the coating network, providing the coating with durable low surface energy properties; while the perfluoroalkyl compounds, as functional additives, further accumulate on the surface during film formation, filling microscopic defects and reducing the surface energy of the coating to an even lower level. The two work synergistically to construct a dense, continuous low surface energy barrier, effectively preventing the spread and penetration of organic solvent molecules on the coating surface.

[0026] In one specific implementation, the undercoat is a chlorinated polyolefin-modified polyurethane dispersion.

[0027] The inventors have discovered that using chlorinated polyolefin-modified polyurethane dispersion as the base coating in this application provides multifaceted performance improvements compared to using chlorinated polyolefin alone.

[0028] On the one hand, the chlorinated polyolefin modified polyurethane dispersion retains the good wettability and adhesion of chlorinated polyolefin to the foamed skin layer, ensuring that the bottom layer can be tightly bonded to the substrate; on the other hand, by introducing polyurethane components, the bottom layer has better flexibility and reactivity, thereby improving its mechanical properties and chemical bonding ability.

[0029] Specifically, the polyurethane component in the base coat has a similar structure to the polycarbonate-type thermoplastic polyurethane in the foam layer, and the two can form hydrogen bonds, further enhancing the interfacial bonding strength between the base coat and the foam layer. Simultaneously, the active groups in the polyurethane component can also chemically react with the carbodiimide crosslinking agent in the top coat, achieving chemical crosslinking between the base coat and the top coat. This chemical bonding mechanism upgrades the interlayer bonding, which originally relied mainly on physical adsorption, to chemical bonding, significantly improving interlayer adhesion.

[0030] Furthermore, the polyurethane component itself has excellent solvent resistance. Introducing it into the underlayer is equivalent to adding a solvent-resistant protective layer to the surface of the foam layer, enhancing the underlayer's own protective capabilities. When the composite material comes into contact with organic solvents, even if the surface layer experiences localized wear, the underlayer can still provide protection due to its solvent resistance and strong bond with the foam layer, preventing direct solvent penetration into the foam layer.

[0031] In one specific implementation, the base fabric layer is selected from one or more of polyethylene, polypropylene foam, or PET base fabric.

[0032] The base fabric layer, acting as the underlying skeleton, constrains the expansion behavior of the foam layer during the foaming process, preventing excessive expansion and cell rupture. During use, it withstands tensile stress, protecting the foam layer from mechanical damage. Both polyethylene and polypropylene foam materials belong to the polyolefin foaming material family, possessing lightweight and soft characteristics, and their density matches that of the foam layer, resulting in a uniform overall feel. PET base fabric features high strength and good heat resistance, exhibiting excellent dimensional stability under the high temperature and pressure environment of supercritical foaming.

[0033] Secondly, this application provides a method for preparing a thermoplastic silicone elastomer foamed skin composite material, using the following technical solution: A method for preparing a thermoplastic silicone elastomer foamed skin composite material includes the following steps: S1-2. Mix amino-terminated polysiloxane, polyester thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent, and fluorinated alkyl polysiloxane evenly to obtain a composite compatibilizer. S2-2, Preparation of foamed skin layer special material: Polycarbonate thermoplastic polyurethane, silicone elastomer, additives and the composite compatibilizer obtained in step S1-2 are melt-blended, extruded and granulated to obtain foamed skin layer special material; S3-2. The foamed skin layer material obtained in step S2-2 is melted and plasticized, extruded into a film, and then compounded with a preheated base fabric layer in a molten state to obtain a skin substrate semi-finished product. S4-2. The surface of the semi-finished skin substrate obtained in step S3-2 is coated with a base coat and a top coat in sequence, and dried to form a surface coating to obtain a semi-finished product after surface finishing. S5-2. The semi-finished product obtained in step S4-2 after surface coating is pressed with a preset pattern using an embossing machine to obtain the embossed semi-finished product. S6-2. Place the embossed semi-finished product obtained in step S5-2 into a supercritical foaming device, so that the foaming medium gas permeates into the foamed skin layer and initiates foaming to form a microporous structure, thereby obtaining the thermoplastic silicone elastomer foamed skin composite material.

[0034] The thermoplastic silicone elastomer foamed skin composite material prepared by the above steps exhibits excellent solvent resistance. During the preparation process, the composite compatibilizer is pre-mixed, allowing the three solubilizing components to form preliminary intermolecular interactions before being added to the substrate, which facilitates the rapid formation of a gradient structure in subsequent processing. The sequence of embossing followed by foaming utilizes the good plasticity of the unfoamed material to precisely press the pattern, and then the expansion force generated by foaming further expands and shapes the pattern, solving the technical problem of easy collapse of embossed foamed materials in traditional processes.

[0035] In summary, this application includes at least one of the following beneficial technical effects: 1. This application achieves efficient compatibilization of the matrix polyurethane and the silicon-based elastomer by using a composite compatibilizer comprising amino-terminated polysiloxane, polyester-type thermoplastic polyurethane grafted polysiloxane copolymer and fluorinated alkyl polysiloxane, which significantly improves the interfacial bonding strength between the two phases and enhances the overall solvent resistance of the composite material.

[0036] 2. This application modifies polyester-type TPU grafted polysiloxane copolymer with silane coupling agent, upgrades the physically entangled interface structure to a chemically cross-linked network, and controls the optimal weight ratio of the three components to achieve the best balance of solvent resistance of the material.

[0037] 3. This application uses fluorine-modified silicone resin in combination with chlorinated polyolefin-modified polyurethane undercoat to construct a dense surface chemical barrier, which solves the technical problems of traditional coating systems being easy to peel off under solvent wiping and rapid deterioration of the undercoat material after the coating is damaged. Detailed Implementation

[0038] The present application will be further described in detail below with reference to embodiments and comparative examples: Some of the raw materials used in the examples and comparative examples: Polybutylene adipate diol was supplied by Shandong Jining Shengli Chemical PBA2000; silicone resin by Dainichi Seika D-5591M; nano silica filler by Yamei Nano SiO2-N-O3; organosilicon wear-resistant additive by Dow Corning DC51; perfluoroalkyl compound by Sichuan Shangfu Technology perfluorohexylethylene 25291-17-2; perfluoropolyether silane by Guangdong Baike Reagent AF-1060; chlorinated polyolefin by Nippon Paper Industries 350S; polyester polyol by Kaiyin Chemical 7380; amino-terminated polydimethylsiloxane by Guangzhou Zhonghaojing Polymer Materials PG180; polycarbonate thermoplastic polyurethane by Dongguan Shuangbang Plastic Raw Material ALC-65D, with approximately 0.2-0.5% residual isocyanate groups; silicone elastomer by TPSIVTP60A; hindered amine antioxidant by BASF Irganox. 1010; The anti-migration UV absorber used is MIASORB® UV-1130.

[0039] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available products.

[0040] Preparation Example 1 The preparation of single-amino-terminated polydimethylsiloxane is as follows: Under nitrogen protection, 30 mL of tetrahydrofuran was cooled to 0 °C in an ice-water bath. 0.42 mL of n-butyllithium solution was added. 15 g of octamethylcyclotetrasiloxane was dissolved in 10 mL of tetrahydrofuran and added to the reaction system. The ice bath was removed, and the mixture was heated to 45 °C and stirred for 5 hours. The reaction system was then cooled to 0 °C, and 0.15 g of dichlorosilane was added and stirred for 1 hour. The reaction solution was poured into 200 mL of methanol and stirred, causing a precipitate to form. The precipitate was washed three times with methanol and dried under vacuum at 40 °C for 4 hours to obtain silane. End-capped polydimethylsiloxane intermediate: 10 g of silane-terminated polydimethylsiloxane intermediate was dissolved in 30 mL of tetrahydrofuran, and 0.2 g of piperidine, 5 mg of palladium acetate, and 0.15 g of triethylamine were added. Under nitrogen protection, the mixture was heated to 55 °C and stirred for 10 hours. The reaction solution was passed through a neutral alumina column and then rotary evaporated. The concentrated reaction solution was poured into 150 mL of methanol and stirred to precipitate the precipitate. The precipitate was washed three times with methanol and dried under vacuum at 50 °C for 12 hours to obtain mono-amino-terminated polydimethylsiloxane.

[0041] Preparation Example 2 The preparation of polyester-type thermoplastic polyurethane-grafted polysiloxane copolymers is as follows: S1-1, Prepolymer Synthesis: Under nitrogen protection, 10g of polybutylene adipate diol and 2.5g of diphenylmethane diisocyanate were added to 30mL of DMF, and the mixture was heated to 80℃ and stirred for 2 hours to obtain a prepolymer solution. S2-1, Chain extension reaction: Dissolve 0.45g of 1,4-butanediol in 5mL of DMF, add it to the prepolymer solution obtained in step S1-1, heat to 80℃ and continue the reaction for 1 hour to obtain the chain-extended thermoplastic polyurethane prepolymer solution. S3-1 Grafting reaction: 1.5g of amino-terminated polydimethylsiloxane and 10mg of dibutyltin dilaurate were added to the chain-extended thermoplastic polyurethane prepolymer solution obtained in step S2-1, which was cooled to 60℃. The reaction was maintained at 60℃ for 4 hours. The reaction solution was poured into 200mL of water, and a precipitate was formed. The precipitate was washed three times with a 1:1 mixture of methanol and water and dried at 80℃ for 24 hours to obtain a polyester-type thermoplastic polyurethane grafted polysiloxane copolymer.

[0042] Preparation Example 3 The preparation of polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent is as follows: 10g of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer prepared in Preparation Example 2 was added to 50mL of DMF and stirred at 60°C. 0.4g of KH-560 was dissolved in 5mL of DMF and added to the reaction system. The temperature was raised to 85°C and the reaction was carried out for 4 hours. The reaction solution was poured into 200mL of methanol and stirred. The precipitate was precipitated, washed three times with methanol, and dried under vacuum at 60°C for 24 hours to obtain the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent.

[0043] Preparation Example 4 The preparation of the topcoat is as follows: 70 parts by weight of silicone resin, 12.5 parts by weight of nano silica, 12.5 parts by weight of organosilicon wear-resistant additive, 4 parts by weight of perfluoroalkyl compound, and 10 parts by weight of carbodiimide crosslinking agent were stirred at 1000 rpm for 0.5 hours at room temperature, then allowed to stand and mature for 0.5 hours, and passed through a 200-mesh sieve to obtain the topcoat.

[0044] Preparation Example 5 The preparation of fluorine-modified silicone resin is as follows: 25 parts by weight of perfluoropolyether silane, 45 parts by weight of phenyltrimethoxysilane, and 25 parts by weight of methyltrimethoxysilane were dissolved in 950 parts by weight of ethanol. The pH of the reaction system was adjusted to 3.5 using hydrochloric acid solution. The reaction was carried out at 55°C for 5 hours for hydrolysis and condensation. After neutralization, the solvent and low molecular weight molecules were removed under reduced pressure to obtain fluorinated modified silicone resin.

[0045] Preparation Example 6 The only difference between Preparation Example 6 and Preparation Example 4 is that 70 parts by weight of silicone resin in Preparation Example 6 were replaced with 70 parts by weight of fluorinated modified silicone resin obtained in Preparation Example 5.

[0046] Preparation Example 7 The preparation of chlorinated polyolefin-modified polyurethane dispersion is as follows: 20g of chlorinated polypropylene was dispersed in 100mL of methylcyclohexane. Then, 4g of maleic anhydride, 4g of styrene, and 2g of benzoyl peroxide were dissolved in 20mL of methylcyclohexane and added to the reaction system. The mixture was heated to 100℃ and reacted for 2 hours. The reaction solution was poured into 500mL of acetone, and a precipitate was formed. The precipitate was washed three times with acetone and dried at 55℃ for 24 hours to obtain maleic anhydride-grafted chlorinated polypropylene. Under nitrogen protection, 18g of polyester polyol, 10g of isophorone diisocyanate, 0.02g of dibutyltin dilaurate, and 10g of NMP were mixed and reacted at 80℃ for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer. 2g of dimethylolpropionic acid and 1.5g of 1,4-butanediol were reacted in 5mL of methylolpropionic acid solution. After dissolving NMP, the above-mentioned polyurethane prepolymer, cooled to 60°C, was added, and the mixture was heated to 70°C and reacted for 2 hours to obtain a carboxyl-containing hydrophilic polyurethane prepolymer. 6g of maleic anhydride-grafted chlorinated polypropylene was dissolved in 10g of NMP, and the above-mentioned carboxyl-containing hydrophilic polyurethane prepolymer was added. The mixture was heated to 75°C and reacted for 3 hours. 1.5g of triethylamine was added and stirred for 0.5 hours. 55g of deionized water was added and stirred for another 0.5 hours. The mixture was then distilled under reduced pressure at 50°C and passed through a 200-mesh sieve to obtain a chlorinated polyolefin-modified polyurethane dispersion. Example Example 1

[0047] The preparation of thermoplastic silicone elastomer foamed skin composite material is as follows: S1-2. Mix 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane evenly to obtain a composite compatibilizer. S2-2, Preparation of foamed skin layer special material: 80 parts by weight of polycarbonate thermoplastic polyurethane, 20 parts by weight of silicone elastomer, 1.6 parts by weight of hindered amine antioxidant, 1.6 parts by weight of ultraviolet absorber and 1.6 parts by weight of composite compatibilizer obtained in step S1-2 are melt-blended at 180°C, extruded and granulated to obtain foamed skin layer special material; S3-2. The foamed skin layer material obtained in step S2-2 is melted and plasticized, extruded into a film, and then laminated with a preheated PET base fabric in a molten state to obtain a skin substrate semi-finished product. S4-2. The surface of the semi-finished skin substrate obtained in step S3-2 is sequentially coated with the bottom coating obtained in Preparation Example 7 with a thickness of 0.2 mm and the top coating obtained in Preparation Example 6 with a thickness of 0.2 mm, and dried to form a surface coating, thereby obtaining the semi-finished product after surface finishing. S5-2. Press the pre-set pattern onto the semi-finished product obtained in step S4-2 using an embossing machine to obtain the embossed semi-finished product. S6-2. Place the embossed semi-finished product obtained in step S5-2 into a supercritical foaming device, using carbon dioxide or nitrogen as the foaming medium gas. Under conditions of 100°C and 20MPa, the gas penetrates into the foamed skin layer and initiates foaming, forming a microporous structure, thus obtaining the thermoplastic silicone elastomer foamed skin composite material. Example 2

[0048] The difference between Example 2 and Example 1 is that in step S1-2 of Example 2, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 0.7 parts by weight of amino-terminated polysiloxane, 0.8 parts by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.1 parts by weight of fluorinated alkyl polysiloxane. Example 3

[0049] The difference between Example 3 and Example 1 is that in step S1-2 of Example 3, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 0.1 parts by weight of amino-terminated polysiloxane, 1.4 parts by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.1 parts by weight of fluorinated alkyl polysiloxane. Example 4

[0050] The difference between Example 4 and Example 1 is that in step S1-2 of Example 4, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 0.1 parts by weight of amino-terminated polysiloxane, 0.8 parts by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.7 parts by weight of fluorinated alkyl polysiloxane. Example 5

[0051] The only difference between Example 5 and Example 1 is that in step S4-2 of Example 5, the underlying coating with a thickness of 0.2 mm prepared in Example 7 is replaced with a chlorinated polyolefin with a thickness of 0.2 mm. Example 6

[0052] The only difference between Example 6 and Example 1 is that the topcoat prepared in Example 6 with a thickness of 0.2 mm in step S4-2 is replaced with the topcoat prepared in Example 4 with a thickness of 0.2 mm.

[0053] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that in steps S1-2 of Comparative Example 1, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 1.6 parts by weight of amino-terminated polysiloxane.

[0054] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that in steps S1-2 of Comparative Example 2, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 1.6 parts by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3.

[0055] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that in steps S1-2 of Comparative Example 3, 0.3 parts by weight of amino-terminated polysiloxane, 1 part by weight of the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent obtained in Preparation Example 3, and 0.3 parts by weight of fluorinated alkyl polysiloxane are replaced with 1.6 parts by weight of fluorinated alkyl polysiloxane.

[0056] Organic solvent resistance test: a) Test method: 1 ml (about 18 to 23 drops) of artificial sweat, 0.5% soapy water, No. 92 gasoline and window washing liquid were dropped onto different positions on the sample surface. The sample was left to stand at room temperature for 5 minutes (1 minute for painted interior parts). Then, a folded white cotton cloth was used to wipe the sample back and forth 10 times within a 50 mm length. The sample was then placed in an environment of (23±2)℃ and (50±3)%RH for 24 hours.

[0057] b) Test results: The appearance of the sample wiping area was evaluated, and the staining of the white cotton cloth was evaluated according to GB / T 251-2008.

[0058] The acid and alkali resistance test was conducted using GB / T3920-2008, involving 500 cycles of rubbing and evaluation of the gray grade (ISO105-A02).

[0059] Oil resistance test: Wipe the surface of the skin with a cloth soaked in the flowing paraffin used in the oil resistance test. After wiping, perform a cycle test {(40℃×80%RH×20h→20℃×50%RH×4h)×3 times. After the test, confirm whether there are any abnormalities on the surface and evaluate the gray level (ISO105-A02).

[0060] For each of the above evaluation requirements, ≥4 units are considered a qualified product. The test results are shown in the table below: Table 1. Solvent resistance tests of each example and comparative example.

[0061] Combining Examples 1-4 and Comparative Examples 1-3, and referring to Table 1, it can be seen that the ratio and integrity of the three components in the composite compatibilizer have a decisive influence on the intrinsic solvent resistance of the foamed skin layer. In Example 1, the ratio of amino-terminated polysiloxane, silane coupling agent-modified polyester thermoplastic polyurethane grafted polysiloxane copolymer, and fluorinated alkyl polysiloxane is within the preferred range, and the three synergistically construct a complete gradient structure of "interface anchoring-molecular bridging-surface migration". In Example 2, the excess of amino-terminated polysiloxane and the deficiency of the other two components resulted in too many interface anchoring points and insufficient bridging and surface migration; in Example 3, the excess of silane coupling agent-modified graft copolymer and the deficiency of the other two components resulted in a large number of polysiloxane side chains failing to effectively connect the two phases due to lack of anchoring; in Example 4, the excess of fluorinated alkyl polysiloxane and the deficiency of the other two components resulted in an excessively thick fluorinated surface layer, affecting the coating adhesion. Comparative Examples 1-3, each lacking two components and retaining only one component, showed the following results: When only amino-terminated polysiloxane was present, there was anchoring without bridging or migration; when only modified graft copolymer was present, there was bridging without anchoring or migration; and when only fluoroalkyl polysiloxane was present, surface energy was reduced but interfacial bonding was absent. This indicates that all three components are indispensable, and only through their synergistic combination in appropriate proportions can a complete gradient structure be constructed, thereby improving the solvent resistance of the composite material.

[0062] Combining Examples 1 and 5, and referring to Table 1, it can be seen that the choice of the undercoat affects the overall protective performance of the composite material. Compared to the pure chlorinated polyolefin used in Example 5, the chlorinated polyolefin-modified polyurethane dispersion used in Example 1 combines adhesion, flexibility, and reactivity, greatly improving the solvent resistance of the composite material.

[0063] Combining Examples 1 and 6, and referring to Table 1, it can be seen that the fluorine modification of the silicone resin in the topcoat has a synergistic effect on surface protection. Compared with the ordinary silicone resin used in Example 6, the fluorine-modified silicone resin used in Example 1 forms a double fluorination effect with the perfluoroalkyl compound, which greatly improves the solvent resistance of the composite material.

[0064] This application constructs a complete protective system from the intrinsic solvent resistance of the foam layer to the surface coating barrier by synergistic use of three components of composite compatibilizer, modification of the bottom polyurethane layer, and fluorination upgrade of the top layer, thereby significantly improving the solvent resistance of the composite material.

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A thermoplastic silicone elastomer foamed skin composite material, characterized in that, It includes a base fabric layer, a foamed skin layer, and a surface coating layer that are stacked sequentially; The foamed skin layer is a microporous elastomer layer foamed by supercritical fluid, comprising the following components in parts by weight: 70-90 parts of polycarbonate thermoplastic polyurethane, 10-30 parts of silicone elastomer, 1-4 parts of additives, and 0.5-2 parts of composite compatibilizer. The composite compatibilizer includes amino-terminated polysiloxane, polyester thermoplastic polyurethane grafted polysiloxane copolymer, and fluorinated alkyl polysiloxane. The surface coating comprises a double-layer coating structure of a topcoat and a basecoat; the topcoat comprises the following components in parts by weight: 60-80 parts of silicone resin, 5-10 parts of nano-silica, 5-10 parts of organosilicon wear-resistant additive, 3-5 parts of perfluoroalkyl compound, and 5-15 parts of carbodiimide crosslinking agent; the basecoat comprises chlorinated polyolefin.

2. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The polyester-type thermoplastic polyurethane grafted polysiloxane copolymer is modified with a silane coupling agent, wherein the silane coupling agent is KH-560.

3. The thermoplastic silicone elastomer foamed skin composite material according to claim 2, characterized in that, The weight ratio of the amino-terminated polysiloxane, the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer modified with a silane coupling agent, and the fluorinated alkyl polysiloxane is 1:(1.5-5):(0.3-1.5).

4. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The polyester-type thermoplastic polyurethane-grafted polysiloxane copolymer is prepared as follows: S1-1, Prepolymer Synthesis: Under nitrogen protection, polybutylene adipate diol and diphenylmethane diisocyanate are added to DMF to react and prepare a prepolymer solution; S2-1, Chain extension reaction: Dissolve 1,4-butanediol in DMF and add it to the prepolymer solution obtained in step S1-1 to react and obtain the chain-extended thermoplastic polyurethane prepolymer solution. S3-1 Grafting reaction: Add mono-amino-terminated polydimethylsiloxane and catalyst to the chain-extended thermoplastic polyurethane prepolymer solution obtained in step S2-1, and then react to obtain the polyester-type thermoplastic polyurethane grafted polysiloxane copolymer.

5. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The additives include anti-migration antioxidants and anti-migration ultraviolet absorbers.

6. The thermoplastic silicone elastomer foamed skin composite material according to claim 5, characterized in that, The anti-migration antioxidant is a hindered amine antioxidant.

7. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The silicone resin is a fluorine-modified silicone resin.

8. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The underlying coating is a chlorinated polyolefin modified polyurethane dispersion.

9. The thermoplastic silicone elastomer foamed skin composite material according to claim 1, characterized in that, The base fabric layer is selected from one or more of polyethylene, polypropylene foam material or PET base fabric.

10. A method for preparing the thermoplastic organosilicon elastomer foamed skin composite material according to any one of claims 1-9, characterized in that, Includes the following steps: S1-2. Mix amino-terminated polysiloxane, polyester thermoplastic polyurethane grafted polysiloxane copolymer modified with silane coupling agent, and fluorinated alkyl polysiloxane evenly to obtain a composite compatibilizer. S2-2, Preparation of foamed skin layer special material: Polycarbonate thermoplastic polyurethane, silicone elastomer, additives and the composite compatibilizer obtained in step S1-2 are melt-blended, extruded and granulated to obtain foamed skin layer special material; S3-2. The foamed skin layer material obtained in step S2-2 is melted and plasticized, extruded into a film, and then compounded with a preheated base fabric layer in a molten state to obtain a skin substrate semi-finished product. S4-2. The surface of the semi-finished skin substrate obtained in step S3-2 is coated with a base coat and a top coat in sequence, and dried to form a surface coating to obtain a semi-finished product after surface finishing. S5-2. The semi-finished product obtained in step S4-2 after surface coating is pressed with a preset pattern using an embossing machine to obtain the embossed semi-finished product. S6-2. Place the embossed semi-finished product obtained in step S5-2 into a supercritical foaming device, so that the foaming medium gas permeates into the foamed skin layer and initiates foaming to form a microporous structure, thereby obtaining the thermoplastic silicone elastomer foamed skin composite material.

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