A thermochromic silicone leather, its preparation method, and its applications

Abstract

This application relates to the field of organosilicon materials technology, and particularly to a thermochromic organosilicon leather, its preparation method, and its applications. The thermochromic organosilicon leather provided by this application comprises a middle layer adhesive and a top layer adhesive. The middle layer adhesive comprises the following raw materials in parts by weight: 30-100 parts vinyl silicone oil, 2-19 parts hydrogen-containing silicone oil, 0.2-1 parts platinum catalyst, 0.001-0.05 parts inhibitor, and 15-40 parts filler. The top layer adhesive comprises the following raw materials in parts by weight: 30-100 parts vinyl silicone oil, 25-40 parts vinyl silicone resin, 2-19 parts hydrogen-containing silicone oil, 0.2-1 parts platinum catalyst, 0.001-0.05 parts inhibitor, 15-40 parts filler, and 2-4 parts color-changing microcapsules. The organosilicon leather provided by this application, by adding color-changing microcapsules to the top layer adhesive, allows the color of the organosilicon leather to change with temperature, thus broadening the application scenarios of organosilicon leather.

Description

Technical Field

[0001] This application relates to the field of organosilicon materials technology, and in particular to a thermochromic organosilicon leather, its preparation method, and its application. Background Technology

[0002] Currently, the artificial leather used in the market is mainly polyurethane leather. However, polyurethane itself is toxic, and the production process generates a large amount of harmful volatile substances. Furthermore, the products have poor temperature resistance, aging resistance, and breathability, resulting in a short lifespan. Therefore, the development of new leather materials is urgently needed. In recent years, silicone leather has become one of the research hotspots in artificial leather. It uses vinyl silicone oil and hydrogen-containing silicone oil as the main raw materials, and is cured through hydrosilylation without the addition of other solvents. No small molecules are released during the production process, which aligns with the concept of green development. Because the entire structure adopts a helical structure with -Si-O-Si as the main chain and methyl groups pointing outwards, and is reinforced with silica, silicone leather has strong weather resistance, stain resistance, abrasion resistance, flexural resistance, and aging resistance, which are superior to natural leather and polyurethane leather.

[0003] Silicone leather generally consists of three parts: a top layer, a middle layer, and a base layer. During manufacturing, non-woven fabric is typically used as the base layer, and silicone materials are used as the top and bottom layer adhesives. For example, patent CN103821008A discloses a three-layer silicone synthetic leather and its preparation method, which is composed of a base layer, a bottom layer adhesive, and a top layer adhesive bonded together sequentially, exhibiting strong abrasion resistance. Patent CN109056357A discloses an abrasion-resistant silicone leather and its preparation method, which improves the abrasion resistance of the silicone leather by incorporating phenyl silicone resin.

[0004] As the applications of silicone leather diversify, higher requirements are being placed on its properties, such as the need for temperature-sensitive color-changing functionality. Therefore, providing a silicone leather capable of temperature-sensitive color-changing is of great importance. Summary of the Invention

[0005] This application provides a thermochromic silicone leather to solve the problem that existing silicone leathers in the related art do not have thermochromic functions.

[0006] In a first aspect, this application provides a thermochromic silicone leather, comprising a middle layer adhesive and a top layer adhesive. The middle layer adhesive comprises the following raw materials in parts by weight: 30-100 parts vinyl silicone oil, 2-19 parts hydrogen-containing silicone oil, 0.2-1 parts platinum catalyst, 0.001-0.05 parts inhibitor, and 15-40 parts filler. The top layer adhesive comprises the following raw materials in parts by weight: 30-100 parts vinyl silicone oil, 25-40 parts vinyl silicone resin, 2-19 parts hydrogen-containing silicone oil, 0.2-1 parts platinum catalyst, 0.001-0.05 parts inhibitor, 15-40 parts filler, and 2-4 parts color-changing microcapsules.

[0007] In some embodiments, the core material of the color-changing microcapsule is a leuco dye, a color developer, and a phase change material, and the wall material is a cationic modified melamine resin, which is prepared from melamine, formaldehyde, and a cationic modifier.

[0008] In some embodiments, the leuco dye is crystal violet lactone or green pigment-5; the color developer is one or a mixture of bisphenol A, bisphenol AF, bisphenol S, methyl gallate, and propyl gallate; the phase change material is one or a mixture of n-dodecanol, n-tetradecanol, n-hexadecanol, and n-octadecanol; the cationic modifier is any one or a mixture of small molecule quaternary ammonium salt cationic modifiers or high molecular weight quaternary ammonium salt cationic modifiers, wherein the small molecule quaternary ammonium salt cationic modifier is selected from one or a mixture of pyridine quaternary ammonium salt compounds and 2,3-epoxypropyltrimethylammonium chloride; and the high molecular weight quaternary ammonium salt cationic modifier is selected from one or a mixture of two of dimethyl diallyl ammonium chloride acrylamide copolymer, polyquaternium-10, and polyacrylamide-co-diallyl dimethylammonium chloride.

[0009] In some preferred embodiments, the pyridine quaternary ammonium salt compound is pyridine quaternary ammonium salt 1 represented by Formula I, pyridine quaternary ammonium salt 2 represented by Formula II, or pyridine quaternary ammonium salt 3 represented by Formula III:

[0010] Formula I: Formula II:

[0011] Formula III:

[0012] In some embodiments, the vinyl content of the ethylene silicone oil in the top and middle layers is 0.6% to 6%. Vinyl groups are mainly located at the chain ends. Too low a vinyl content will affect the strength of the silicone rubber, while too high a content will reduce its elongation at break. The viscosity of the vinyl silicone oil is 5000 to 30000 Pa·s. Too low a viscosity will reduce the elongation at break and tear strength of the silicone rubber, while too high a viscosity will affect the actual process operation. Through comparison of different options, a vinyl silicone oil with a viscosity of 5000 Pa·s is preferred, which can balance the elongation at break, tear performance, and process operability.

[0013] In some embodiments, the vinyl silicone resin is methyl vinyl MQ silicone resin.

[0014] In some preferred embodiments, the vinyl content of the methyl vinyl MQ silicone resin is 0.0519 mol / 100g.

[0015] In some embodiments, the hydrogen content of the hydrogen-containing silicone oil is 0.79–1.55 mol / 100g.

[0016] In some embodiments, the platinum catalyst is any one or a mixture of isopropanol chloroplatinate, tetrahydrofuran chloroplatinate, divinyltetramethyldisiloxane chloroplatinate complex, chloroplatinate-1,3,5,7-tetravinyl-1,3,5,7-tetramethyl-cyclotetrasiloxane, and divinyltetramethyldisiloxane chloroplatinate; the platinum atom content in the platinum catalyst is 100 to 10,000 ppm.

[0017] In some embodiments, the inhibitor is one of methylbutynol, ethynylcyclohexanol, alkynyl-containing maleic acid, or a derivative thereof; the amount of inhibitor added is determined according to the type and the required operating time and vulcanization temperature.

[0018] In some embodiments, the filler is hydrophobic silica, hydrophilic silica, fumed silica, or hydrophobic fumed silica, preferably fumed hydrophobic silica, with a specific surface area of ​​200-330 m². 2 / g can improve the mechanical properties of liquid silicone rubber for artificial leather, and the larger the specific surface area, the better the reinforcing effect. However, adding too much will increase the overall viscosity of the rubber compound, which is not conducive to subsequent coating operations. Controlling the ratio of vinyl silicone oil and silica is crucial. At the same time, if the specific surface area is too small, the viscosity of the rubber compound will decrease, but the mechanical properties will decrease. In addition, when the specific surface area is greater than 300m², 2 At a specific surface area of ​​200-330 m² / g, even hydrophobic materials will exhibit gelation when placed at room temperature. Therefore, materials with a specific surface area of ​​200-330 m² / g are selected. 2 The range of / g is more suitable.

[0019] Secondly, this application also provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0020] Step S101: Add vinyl silicone oil, filler and vinyl silicone resin to a kneader in batches, stir thoroughly, and stir under vacuum at 150°C for 3 hours to obtain the first base adhesive.

[0021] Step S102: Add hydrogen-containing silicone oil, inhibitor, platinum catalyst and color-changing microcapsules to the first base adhesive and stir to disperse it evenly to obtain the topcoat adhesive;

[0022] Step S103: Add vinyl silicone oil and filler to the kneader in batches, stir thoroughly, and stir under vacuum at 150°C for 3 hours to obtain the second base adhesive;

[0023] Step S104: Add hydrogen-containing silicone oil, inhibitor, and platinum catalyst to the second base adhesive and stir until evenly dispersed to obtain the middle layer adhesive;

[0024] Step S105: Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod to make the top layer adhesive evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0025] Step S106: Apply the intermediate layer adhesive to the substrate, scrape out the appropriate thickness with a wire rod, so that the intermediate layer adhesive is evenly distributed on the substrate, and cure at 70°C for 30 seconds.

[0026] Step S107: Transfer the release paper and the substrate together, press them together with uniform force, and then place them in an oven at 120°C for about 20 minutes to cure. After curing, cool to room temperature and peel off the release paper to obtain the thermochromic silicone leather.

[0027] In some embodiments, the color-changing microcapsules are prepared by the following process:

[0028] S201, melamine, formaldehyde and cationic modifier are mixed, an alkaline solution is added to adjust the pH value, and the mixture is heated to react, thus obtaining cationic modified melamine resin prepolymer;

[0029] S202, a core material solution is obtained by mixing and melting leuco dye, color developer and phase change material;

[0030] S203, add acid solution to an anionic emulsifier to adjust pH value, heat, then add core material solution to an anionic emulsifier for emulsification to obtain color-changing core material emulsion;

[0031] S204, cationic modified melamine resin prepolymer is added to color-changing core material emulsion, heated and stirred, acid solution is added to adjust the pH value, heated again, and then cooled to room temperature to obtain color-changing microcapsule emulsion;

[0032] S205, add deionized water to the color-changing microcapsule emulsion for dilution, and then dry to obtain color-changing microcapsule powder.

[0033] In some embodiments, the alkaline solution is one or a mixture of sodium carbonate, triethanolamine, and sodium hydroxide; the acidic solution is one or a mixture of citric acid, acetic acid, and sulfuric acid; and the anionic emulsifier is styrene-maleic anhydride or sodium dodecylbenzenesulfonate.

[0034] In some embodiments, the molar ratio of melamine to formaldehyde is 1:3-1:4, the molar ratio of melamine to cationic modifier is 1:0.03-1:0.08, the weight ratio of cationic modified melamine resin prepolymer to core material solution is 1:1-1:4, the molar ratio of leuco dye to color developer is 1:3-1:6, and the mass of phase change material is 80%-90% of the total mass of core material.

[0035] In some embodiments, in step S201, an alkaline solution is added to adjust the pH value to 8.3-8.6, and the heating temperature is 75-85°C; in step S202, the melting temperature is 125-135°C; in step S203, an acid solution is added to adjust the pH value to 4-5, and the heating temperature is 70-80°C; in step S204, an acid solution is added to adjust the pH value to 4-5, and the heating temperature is 70-80°C, with a reheating temperature of 85-95°C; in step S205, the drying temperature is 80-90°C.

[0036] Thirdly, this application provides the application of the aforementioned thermochromic silicone leather in textiles, home furnishings, automotive interiors, and automotive seats.

[0037] The wall material of the color-changing microcapsules used in this application is a cationic modified melamine resin prepolymer. The structure of the cationic modified melamine prepolymer contains both positive and negative charges. During the preparation process, it can increase the emulsification performance, reduce the introduction of bubbles, and reduce the empty capsule rate by interacting with the positive and negative charges of the emulsifier. At the same time, the cationic modified melamine prepolymer has good mechanical properties and thermal stability. It can maintain the integrity of the capsule body under the impact of external force. After being added to silicone leather, the capsule body exhibits excellent integrity and can enhance the mechanical properties of silicone leather.

[0038] The beneficial effects of the technical solution provided in this application include:

[0039] 1. The silicone leather provided in this application incorporates color-changing microcapsules into the surface adhesive. On the one hand, this allows the color of the silicone leather to change with temperature, thus broadening its application scenarios. On the other hand, since the color-changing microcapsules are fine particles, they can provide a certain degree of reinforcement to the silicone leather. The silicone leather provided in this application has a tear strength of 18-23 KN / m, a tensile strength of 5-8 MPa, and a hardness of 62-68 MPa.

[0040] 2. The middle layer adhesive of this application provides a strong interlayer adhesion between the substrate and the top layer adhesive through the combined action of various chemical reactions, giving the silicone leather a soft and smooth texture. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of the thermochromic silicone leather of this application;

[0043] Figure 2 The color display diagram of the silicone leather of Example 1 at room temperature and 33°C is shown. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] This application provides a thermochromic silicone leather to solve the problem that existing silicone leathers in the related art do not have thermochromic functions.

[0046] This application provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0047] Step S101: By weight, 30-100 parts of vinyl silicone oil, 15-40 parts of filler, and 25-40 parts of vinyl silicone resin are added to a kneader in batches, stirred thoroughly, and then vacuumed at 150°C for 3 hours to obtain the first base adhesive.

[0048] Step S102: By weight, add 2-19 parts of hydrogen-containing silicone oil, 0.001-0.05 parts of inhibitor, 0.2-1 parts of platinum catalyst and 2-4 parts of color-changing microcapsules to the first base adhesive and stir to disperse them evenly to obtain the surface adhesive.

[0049] Step S103: By weight, 30-100 parts of vinyl silicone oil and 15-40 parts of filler are added to the kneader in batches, stirred thoroughly, vacuumed at 150°C, and stirred for 3 hours to obtain the second base adhesive.

[0050] Step S104: By weight, add 2-19 parts of hydrogen-containing silicone oil, 0.001-0.05 parts of inhibitor, and 0.2-1 parts of platinum catalyst to the second base adhesive and stir until evenly dispersed to obtain the middle layer adhesive;

[0051] Step S105: Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod to make the top layer adhesive evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0052] Step S106: Apply the intermediate layer adhesive to the substrate, scrape out the appropriate thickness with a wire rod, so that the intermediate layer adhesive is evenly distributed on the substrate, and cure at 70°C for 30 seconds.

[0053] Step S107: Transfer the release paper and the substrate together, press them together with uniform force, and then place them in an oven at 120°C for about 20 minutes to cure.

[0054] Step S108: After complete curing, cool to room temperature and peel off the release paper to obtain the thermochromic silicone leather. A schematic diagram of the structure of this silicone leather is shown below. Figure 1 .

[0055] The thermochromic silicone leather and its preparation method provided in this application will be described in detail below with reference to embodiments and comparative examples.

[0056] The preparation process of the color-changing microcapsules used in Examples 1-4 below is as follows:

[0057] (1) Preparation of cationic modified melamine resin prepolymer: 30g melamine, 60g formaldehyde aqueous solution (37%) and 4.7g pyridine quaternary ammonium salt 1 were added to a three-necked flask, and triethanolamine solution (10%) was added dropwise until the pH was 8.5. The mixture was heated to 80°C in a water bath, kept warm and stirred for 1.5h, and then discharged to obtain a colorless, clear and transparent cationic modified melamine resin prepolymer.

[0058] (2) Preparation of core material solution: Take 65g hexadecyl alcohol, 2g crystal violet lactone and 6g bisphenol AF in a beaker, stir and heat to 135℃ to melt, and obtain core material solution;

[0059] (3) Preparation of color-changing core material emulsion: Take 130g SMA (5%) emulsifier, add citric acid (10%) dropwise until pH is 4.5, heat to 75℃, add core material solution and emulsify on an emulsifier for 15min to obtain color-changing core material emulsion;

[0060] (4) Preparation of color-changing microcapsule emulsion: Take 46g of cationic modified melamine resin prepolymer and add it to the color-changing core material emulsion. After keeping it warm for 1h under water bath stirring at 70℃, add citric acid (10%) dropwise until the pH is 4.5. The system is heated to 95℃ and kept warm for 2h before being cooled to room temperature and discharged to obtain the color-changing microcapsule emulsion.

[0061] (5) Preparation of color-changing microcapsule powder: The color-changing microcapsule emulsion was diluted with deionized water and then spray-dried. The outlet air temperature was controlled at 80℃ to obtain color-changing microcapsule powder. The color-changing microcapsule is blue at room temperature, begins to fade at 28℃, and completely fades to white at 31℃.

[0062] Example 1:

[0063] Example 1 provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0064] (1) By weight, 95 parts of 5000 Pa·S vinyl silicone oil, 40 parts of silica, 30 parts of methyl vinyl MQ silicone resin and 5 parts of 1300 Pa·S vinyl silicone oil were added to the kneader in batches, stirred thoroughly, and vacuumed at 150°C for 3 hours to obtain the first base adhesive.

[0065] (2) By mass, add 3 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.05 parts of methylbutynol, 0.375 parts of chloroplatinic acid-divinyltetramethyldisiloxane and 3 parts of color-changing microcapsules to the first base adhesive, stir for 30 min to disperse it evenly, and obtain the topcoat adhesive.

[0066] (3) By weight, 90 parts of 30000 Pa·S vinyl silicone oil, 5 parts of 500 Pa·S vinyl silicone oil, 5 parts of 1300 Pa·S vinyl silicone oil and 20 parts of silica are added to the kneader in batches, stirred thoroughly, vacuumed at 150°C and stirred for 3 hours to obtain the second base adhesive.

[0067] (4) By mass, add 2.3 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.05 parts of methylbutynol, and 0.375 parts of chloroplatinic acid-divinyltetramethyldisiloxane to the second base adhesive, stir for 30 min, disperse evenly, and obtain the middle layer adhesive.

[0068] (5) Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod, so that the top layer adhesive is evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0069] (6) Apply the middle layer adhesive to the substrate non-woven fabric, scrape out the appropriate thickness with a wire rod, so that the middle layer adhesive is evenly distributed on the substrate, and cure at 70°C for 30 seconds.

[0070] (7) Transfer the release paper and the substrate nonwoven fabric to make them stick together. Press them together with a uniform force until they are completely bonded. Then place them in an oven at 120°C and heat to cure for about 20 minutes. After curing, cool to room temperature and peel off the release paper to obtain the thermochromic silicone leather.

[0071] The thermochromic silicone leather prepared in Example 1 is blue at room temperature and becomes colorless when the temperature is above 31°C.

[0072] The color display of the silicone leather in Example 1 at room temperature and 33°C is shown in the figure. Figure 2 a and Figure 2 b.

[0073] Example 2:

[0074] Example 2 provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0075] (1) By weight, 60 parts of 5000 Pa·S vinyl silicone oil, 25 parts of silica, 30 parts of methyl vinyl MQ silicone resin and 10 parts of 1300 Pa·S vinyl silicone oil were added to the kneader in batches, stirred thoroughly, and vacuumed at 150°C for 3 hours to obtain the first base adhesive.

[0076] (2) By mass, add 3.5 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.02 parts of ethynylcyclohexanol, 0.5 parts of isopropanol chloroplatinic acid solution and 2.5 parts of color-changing microcapsules to the first base adhesive, stir for 30 min to disperse it evenly, and obtain the top layer adhesive.

[0077] (3) By weight, 50 parts of 30000 Pa·S vinyl silicone oil, 5 parts of 500 Pa·S vinyl silicone oil, 10 parts of 1300 Pa·S vinyl silicone oil and 20 parts of silica are added to the kneader in batches, stirred thoroughly, vacuumed at 150°C and stirred for 3 hours to obtain the second base adhesive.

[0078] (4) By mass, add 3.5 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of isopropanol chloroplatinic acid solution to the second base adhesive, stir for 30 min, disperse evenly, and obtain the middle layer adhesive.

[0079] (5) Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod, so that the top layer adhesive is evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0080] (6) Apply the intermediate layer adhesive to the substrate and scrape out the appropriate thickness with a wire rod so that the intermediate layer adhesive is evenly distributed on the substrate. Curing time is 30 seconds at 70°C.

[0081] (7) Transfer the release paper and the substrate together, press them together with a uniform force, and then place them in an oven at 120°C for about 20 minutes to cure. After curing, cool to room temperature and peel off the release paper to obtain thermochromic silicone leather.

[0082] The thermochromic silicone leather prepared in Example 2 is blue at room temperature and becomes colorless when the temperature is above 31°C.

[0083] Example 3:

[0084] Example 3 provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0085] (1) By weight, 75 parts of 5000 Pa·S vinyl silicone oil, 35 parts of silica, 30 parts of methyl vinyl MQ silicone resin and 5 parts of 1300 Pa·S vinyl silicone oil were added to the kneader in batches, stirred thoroughly, and vacuumed at 150°C for 3 hours to obtain the first base adhesive.

[0086] (2) By mass, add 4 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.008 parts of alkynyl maleic acid, 0.7 parts of chloroplatinic acid-divinyltetramethyldisiloxane complex and 3.5 parts of color-changing microcapsules to the first base adhesive, stir for 30 min to disperse it evenly, and obtain the topcoat adhesive.

[0087] (3) By weight, 80 parts of 30000 Pa·S vinyl silicone oil, 5 parts of 500 Pa·S vinyl silicone oil, 5 parts of 1300 Pa·S vinyl silicone oil and 35 parts of silica were added to the kneader in batches, stirred thoroughly, vacuumed at 150°C and stirred for 3 hours to obtain the second base adhesive.

[0088] (4) By mass, add 12 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.02 parts of alkynyl maleic acid, and 0.4 parts of chloroplatinic acid-divinyltetramethyldisiloxane complex to the second base adhesive, stir for 30 min, disperse evenly, and obtain the middle layer adhesive.

[0089] (5) Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod, so that the top layer adhesive is evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0090] (6) Apply the intermediate layer adhesive to the substrate and scrape out the appropriate thickness with a wire rod so that the intermediate layer adhesive is evenly distributed on the substrate. Curing time is 30 seconds at 70°C.

[0091] (7) Transfer the release paper and the substrate together, press them together with a uniform force, and then place them in an oven at 120°C for about 20 minutes to cure. After curing, cool to room temperature and peel off the release paper to obtain thermochromic silicone leather.

[0092] The thermochromic silicone leather prepared in Example 3 is blue at room temperature and becomes colorless when the temperature is above 31°C.

[0093] Example 4:

[0094] Example 4 provides a method for preparing thermochromic silicone leather, comprising the following steps:

[0095] (1) By weight, 85 parts of 5000 Pa·S vinyl silicone oil, 30 parts of silica, 30 parts of methyl vinyl MQ silicone resin and 5 parts of 1300 Pa·S vinyl silicone oil were added to the kneader in batches, stirred thoroughly, and vacuumed at 150°C for 3 hours to obtain the first base adhesive.

[0096] (2) By mass, add 3 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.04 parts of ethynylcyclohexanol, 0.8 parts of tetrahydrofuran chloroplatinate solution and 4 parts of color-changing microcapsules to the first base adhesive, stir for 30 min to disperse it evenly, and obtain the surface adhesive.

[0097] (3) By weight, 80 parts of 30000 Pa·S vinyl silicone oil, 5 parts of 500 Pa·S vinyl silicone oil, 5 parts of 1300 Pa·S vinyl silicone oil and 30 parts of silica are added to the kneader in batches, stirred thoroughly, vacuumed at 150°C and stirred for 3 hours to obtain the second base adhesive.

[0098] (4) By mass, add 4 parts of hydrogen-containing silicone oil with a hydrogen content of 0.79 mol / 100g, 0.01 parts of ethynylcyclohexanol, and 0.3 parts of tetrahydrofuran chloroplatinate solution to the second base adhesive, stir for 30 min, disperse evenly, and obtain the middle layer adhesive.

[0099] (5) Apply the top layer adhesive to the release paper, scrape out the appropriate thickness with a wire rod, so that the top layer adhesive is evenly dispersed and of uniform thickness, and cure at 70℃ for 5 minutes to achieve a semi-cured state.

[0100] (6) Apply the intermediate layer adhesive to the substrate and scrape out the appropriate thickness with a wire rod so that the intermediate layer adhesive is evenly distributed on the substrate. Curing time is 30 seconds at 70°C.

[0101] (7) Transfer the release paper and the substrate together, press them together with a uniform force, and then place them in an oven at 120°C for about 20 minutes to cure. After curing, cool to room temperature and peel off the release paper to obtain thermochromic silicone leather.

[0102] The thermochromic silicone leather prepared in Example 4 is blue at room temperature and becomes colorless when the temperature is above 31°C.

[0103] Comparative Example 1:

[0104] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not add color-changing microcapsules during the preparation of thermochromic silicone leather; the rest of the process is basically the same as that of Example 1.

[0105] Comparative Example 2:

[0106] The only difference between Comparative Example 2 and Example 1 is that the wall material of the color-changing microcapsules used is different; otherwise, they are basically the same as Example 1.

[0107] The preparation process of the color-changing microcapsules added in Comparative Example 2 during the preparation of thermochromic silicone leather is as follows:

[0108] (1) Preparation of melamine-formaldehyde prepolymer: 30g of melamine and 60g of formaldehyde aqueous solution (37%) were added to a three-necked flask, and triethanolamine solution (10%) was added dropwise until the pH was 8.5. The mixture was heated to 80°C in a water bath, kept warm and stirred for 1.5h, and then discharged to obtain a colorless, clear and transparent melamine-formaldehyde prepolymer.

[0109] (2) Preparation of core material solution: Take 65g hexadecyl alcohol, 2g crystal violet lactone and 6g bisphenol AF in a beaker, stir and heat to 135℃ to melt, and obtain core material solution;

[0110] (3) Preparation of color-changing core material emulsion: Take 130g SMA (5%) emulsifier, add citric acid (10%) dropwise until pH is 4.5, heat to 75℃, add core material solution and emulsify on an emulsifier for 15min to obtain color-changing core material emulsion;

[0111] (4) Preparation of color-changing microcapsule emulsion: Take 46g of melamine-formaldehyde prepolymer and add it to the color-changing core material emulsion. After keeping it warm for 1h under water bath stirring at 70℃, add citric acid (10%) dropwise until the pH is 4.5. The system is heated to 95℃ and kept warm for 2h before being cooled to room temperature and discharged to obtain the color-changing microcapsule emulsion.

[0112] (5) Preparation of color-changing microcapsule powder: The color-changing microcapsule emulsion was diluted with deionized water and then spray-dried. The outlet air temperature was controlled at 80℃ to obtain color-changing microcapsule powder. The color-changing microcapsule is blue at room temperature, begins to fade at 28℃, and completely fades to white at 31℃.

[0113] The silicone leathers prepared in Examples 1-4, Comparative Example 1, and Comparative Example 2 were subjected to performance tests. Specifically, the materials were tested in accordance with GB / T532-2008. Five samples were cut using a dumbbell-shaped rubber cutter and a crescent-shaped rubber cutter, respectively. The test results are shown in Table 1.

[0114] Table 1: Performance test results of silicone leathers prepared in Examples 1-4 and Comparative Examples 1-2

[0115]

[0116] As can be seen from the data in Example 1 and Comparative Example 1 in Table 1, the addition of color-changing microcapsules with cationic modified wall material can improve the tear strength and hardness of silicone leather. As can be seen from the data in Example 1 and Comparative Example 2, the addition of color-changing microcapsules with unmodified wall material results in a decrease in the tear strength, elongation at break, and other properties of silicone leather. The applicant analyzes that this is because the wall material of the microcapsules obtained by cationic modification is more dense and has better wear resistance. When added to silicone leather, it can act as a filler to enhance the mechanical properties of silicone leather. On the other hand, the wall material of the unmodified microcapsules has poor density, and it is easy to introduce air bubbles during emulsification, resulting in a high empty capsule rate. After being added to silicone leather, the integrity of the capsule body is poor, thus causing a decrease in the mechanical properties of silicone.

[0117] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0118] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0119] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A thermochromic silicone leather, characterized by, The middle layer glue comprises the following raw materials in parts by mass: vinyl silicone oil 30-100 parts, hydrogen-containing silicone oil 2-19 parts, platinum catalyst 0.2-1 part, inhibitor 0.001-0.05 part, and filler 15-40 parts; and the surface layer glue comprises the following raw materials in parts by mass: vinyl silicone oil 30-100 parts, vinyl silicone resin 25-40 parts, hydrogen-containing silicone oil 2-19 parts, platinum catalyst 0.2-1 part, inhibitor 0.001-0.05 part, filler 15-40 parts, and color-changing microcapsule 2-4 parts. The core material of the color-changing microcapsule is leuco dye, color developer and phase change material, and the wall material is cationic modified melamine resin prepared from melamine, formaldehyde and cationic modifier; the color-changing microcapsule is prepared by the following process: mixing melamine, formaldehyde and cationic modifier, adding alkali solution to adjust pH value, heating to obtain cationic modified melamine resin prepolymer; mixing leuco dye, color developer and phase change material to obtain core material solution; adding acid solution to anionic emulsifier to adjust pH value, heating, then adding core material solution to the anionic emulsifier for emulsification to obtain color-changing core material emulsion; adding cationic modified melamine resin prepolymer to the color-changing core material emulsion, heating and stirring, adding acid solution to adjust pH value, heating again, then cooling to room temperature to obtain color-changing microcapsule emulsion; adding deionized water to the color-changing microcapsule emulsion for dilution, then drying to obtain color-changing microcapsule powder; the cationic modifier is any one or mixture of small molecule quaternary ammonium salt cationic modifier and high molecular quaternary ammonium salt cationic modifier, the small molecule quaternary ammonium salt cationic modifier is a mixture of one or more of pyridine quaternary ammonium salt compounds and 2,3-epoxypropyl trimethyl ammonium chloride; the high molecular quaternary ammonium salt cationic modifier is a mixture of one or both of dimethyldiallyl ammonium chloride acrylamide copolymer and polyquaternary ammonium salt-10; the anionic emulsifier is styrene-maleic anhydride or sodium dodecyl benzene sulfonate.

2. The thermochromic silicone leather according to claim 1, characterized in that, The leuco dye is crystal violet lactone or chlorophyllin-5; the color developer is a mixture of one or more of bisphenol A, bisphenol AF, bisphenol S, methyl gallate and propyl gallate; and the phase change material is a mixture of one or more of n-dodecanol, n-tetradecanol, n-hexadecanol and n-octadecanol.

3. The thermochromic silicone leather according to claim 1, characterized in that, The platinum catalyst is any one or mixture of isopropyl alcohol chloroplatinic acid, tetrahydrofuran chloroplatinic acid, chloroplatinic acid-divinyl tetramethyl disiloxane complex, chloroplatinic acid-1,3,5,7-tetraethenyl-1,3,5,7-tetramethyl-cyclo tetrasiloxane and chloroplatinic acid-divinyl tetramethyl disiloxane; the inhibitor is one of methyl butynyl alcohol, ethynyl cyclohexanol, acetylenic group-containing maleic acid or derivative thereof; and the filler is a mixture of any one or more of hydrophobic silica, hydrophilic silica, fumed silica and hydrophobic fumed white carbon black.

4. Process for the preparation of a thermochromic silicone leather according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: S101, mixing the vinyl silicone oil, filler and vinyl silicone resin, vacuum stirring to obtain a first base glue; S102, adding hydrogen-containing silicone oil, inhibitor, platinum catalyst and color-changing microcapsule to the first base glue and stirring to disperse uniformly to obtain a surface layer glue; S103, mixing the vinyl silicone oil and filler, vacuum stirring to obtain a second base glue; S104, adding hydrogen-containing silicone oil, inhibitor and platinum catalyst to the second base glue and stirring to disperse uniformly to obtain a middle layer glue; S105, coating the surface layer glue on a release paper and heating and curing; S106, coating the middle layer glue on a substrate and heating and curing; S107, transferring and pasting the release paper and the substrate, then heating and curing, cooling to room temperature after complete curing, and peeling off the release paper to obtain the temperature-sensitive color-changing silicone leather.

5. The method for producing a thermochromic silicone leather according to claim 4, characterized by, The color-changing microcapsule is prepared by the following process: S201, mixing melamine, formaldehyde and cationic modifier, adding an alkali solution to adjust the pH value, and heating to obtain a cationic modified melamine resin prepolymer; S202, melting and mixing leuco dye, color developing agent and phase change material to obtain a core material solution; S203, adding an acid solution to an anionic emulsifier to adjust the pH value, heating, then adding the core material solution to the anionic emulsifier to emulsify to obtain a color-changing core material emulsion; S204, adding the cationic modified melamine resin prepolymer to the color-changing core material emulsion, heating and stirring, adding an acid solution to adjust the pH value, heating again, then cooling to room temperature to obtain a color-changing microcapsule emulsion; S205, adding deionized water to the color-changing microcapsule emulsion to dilute, then drying to obtain a color-changing microcapsule powder.

6. The method for producing a thermochromic silicone leather according to claim 5, characterized by, The alkali solution is a mixture of one or more of sodium carbonate, triethanolamine and sodium hydroxide; and the acid solution is a mixture of one or more of citric acid, acetic acid and sulfuric acid.

7. The method for producing a thermochromic silicone leather according to claim 5, characterized by, The molar ratio of melamine to formaldehyde is 1:3-1:4, the molar ratio of melamine to cationic modifier is 1:0.03-1:0.08, the weight ratio of cationic modified melamine resin prepolymer to core material solution is 1:1-1:4, and the molar ratio of leuco dye to color developing agent is 1:3-1:6; the mass of the phase change material is 80%-90% of the total mass of the core material.

8. The method for producing a thermochromic silicone leather according to claim 5, characterized by, In step S201, the pH value is adjusted to 8.3-8.6 by adding the alkali solution, and the heating temperature is 75-85℃; in step S202, the melting temperature is 125-135℃; in step S203, the pH value is adjusted to 4-5 by adding the acid solution, and the heating temperature is 70-80℃; in step S204, the pH value is adjusted to 4-5 by adding the acid solution, the heating temperature is 70-80℃, and the re-heating temperature is 85-95℃; and in step S205, the drying temperature is 80-90℃.

9. Application of the temperature-sensitive color-changing silicone leather of any one of claims 1-3 or prepared by the preparation method of any one of claims 4-8 to textiles, home supplies, automotive interiors and automotive seats.

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