3C electronic organic silicon leather material and preparation method thereof

Abstract

The invention relates to a 3C electronic organic silicon leather material and a preparation method thereof, and belongs to the technical field of organic silicon leather, the organic silicon leather material comprises an organic silicon surface layer, an organic silicon primer layer and a base material, each of the organic silicon surface layer and the organic silicon primer layer comprises the following components: vinyl silicone oil, methyl vinyl silicone resin, MQ type hydrogen-containing silicone resin, a hydrogen-containing cross-linking agent, a platinum catalyst and a flame-retardant heat-conducting filler, and the organic silicon primer layer further comprises a tackifier. The flame-retardant heat-conducting filler is obtained by modifying magnesium oxide with a silane coupling agent, mixing the modified magnesium oxide with graphene and then carrying out heat treatment. The flame-retardant heat-conducting filler provided by the invention is applied to organic silicon leather, has good heat conductivity while having a flame-retardant effect, and also has good mechanical properties, thermal fatigue resistance and antifouling properties. The flame-retardant heat-conducting filler is excellent in dispersity, excellent in compatibility with vinyl silicone oil, methyl vinyl silicone resin and MQ type hydrogen-containing silicone resin and relatively strong in interaction force.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon leather, and specifically relates to a 3C electronic organic silicon leather material and a preparation method thereof. Background Art

[0002] After a series of changes from plastic, metal, glass, etc., the shell materials of 3C electronic fast-moving consumer goods have been transformed. In order to be different from the cold and hard appearance of traditional electronic products, silicone leather is used to soften the touch, and it also has the characteristics of anti-fouling, dustproof, wear-resistant, and scratch-resistant. Existing silicone leather generally consists of a three-layer structure of silicone surface layer, silicone primer layer, and substrate. The main raw materials for the preparation of silicone surface layer and silicone primer layer include vinyl silicone oil, methyl vinyl silicone resin, and MQ type hydrogenated silicone resin. The substrate includes woven fabric, PVC leather, PU leather, etc.

[0003] As the shell material of 3C electronic fast-moving consumer goods, protecting electronic products inside, such as tablets and mobile phones, will greatly affect the heat dissipation of electronic products. CN114703675B discloses a kind of organosilicon synthetic leather for electronic packaging and its preparation method, in which spherical fillers, spherical silicon micropowder and spherical aluminum oxide are added to the organosilicon surface layer component, which has a certain heat conduction function, but it is only added to the organosilicon surface layer, and the main purpose is to improve the antifouling and wear resistance of the organosilicon leather. The heat dissipation effect of the organosilicon leather as a whole is still not ideal. At the same time, in order to make the organosilicon leather shell material have a certain flame retardancy, antimony trioxide and ammonium polyphosphate are generally used as flame retardants to be added to the organosilicon leather raw materials. They are not compatible with vinyl silicone oil, methyl vinyl silicone resin, and MQ type hydrogen-containing silicone resin, resulting in limitations in the mechanical properties, thermal conductivity and flame retardant effects of the organosilicon leather. Summary of the invention

[0004] The purpose of the present invention is to provide a 3C electronic silicone leather material and a preparation method thereof in order to solve the above problems, which can be used as a protective shell material for 3C electronic products.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] The present invention provides a 3C electronic organic silicon leather material, comprising an organic silicon surface layer, an organic silicon primer layer and a substrate, wherein the organic silicon surface layer and the organic silicon primer layer both comprise the following components: vinyl silicone oil, methyl vinyl silicone resin, MQ type hydrogen-containing silicone resin, a hydrogen-containing crosslinking agent, and a platinum catalyst, and the organic silicon primer layer further comprises a tackifier;

[0007] The components of the organic silicon surface layer and the organic silicon base layer also include flame retardant thermal conductive filler, and the flame retardant thermal conductive filler is obtained by mixing magnesium oxide with graphene after being modified by a silane coupling agent and then subjected to heat treatment;

[0008] The added amount of the flame retardant heat conductive filler accounts for 10-20% of the total mass of the raw materials for preparing the organic silicon surface layer or the organic silicon base adhesive layer.

[0009] As a further optimization scheme of the present invention, the preparation of the flame retardant thermal conductive filler comprises the following steps:

[0010] (1) mixing graphene powder with citric acid solution, adjusting the pH to alkaline, performing a hydrothermal reaction, washing and drying the reactant, and obtaining a solid;

[0011] (2) uniformly dispersing the dried magnesium oxide powder in ethanol, adding a silane coupling agent, heating in a water bath, centrifuging and collecting the precipitate, and vacuum drying to obtain a solid II;

[0012] (3) The solid one and the solid two are uniformly dispersed in a solvent, and the filtrate is subjected to solid phase heat treatment after filtration, and a flame retardant thermal conductive filler is obtained after grinding.

[0013] As a further optimization scheme of the present invention, in the step (1), the mass fraction of the citric acid solution is 85-95wt%, the amount of graphene added is 50-100g / L, the pH is adjusted to 7-8 using sodium hydroxide, and then the solution is sealed in a reactor.

[0014] As a further optimization scheme of the present invention, in the step (1), the temperature of the hydrothermal reaction is 200-240° C., and the reaction time is 12-48 hours.

[0015] As a further optimization scheme of the present invention, in the step (2), the mass fraction of ethanol is 95wt%, the silane coupling agent is an aminosilane coupling agent, and the added amount of the silane coupling agent is 2-3% of the mass of the magnesium oxide powder.

[0016] As a further optimization scheme of the present invention, in the step (2), the water bath heating temperature is 95-100° C., and the heating time is 10-20 min.

[0017] As a further optimization scheme of the present invention, the step (3) is specifically: solid one and solid two are uniformly dispersed in ethanol at a mass ratio of 1:10-20, the mixture is filtered after dispersion, and the filtrate is subjected to solid phase heat treatment at a heat treatment temperature of 600-800°C for a treatment time of 1-2h. After cooling, the solid phase is ground to obtain a flame retardant thermal conductive filler.

[0018] The present invention also provides a method for preparing the above 3C electronic silicone leather material, comprising the following steps:

[0019] (1) mixing the components of the silicone surface layer uniformly, coating it on a release paper and heating it with hot air;

[0020] (2) The substrate is immersed in an ethanol solution containing a flame retardant thermal conductive filler, left to stand for a period of time and then picked up and dried, the components of the silicone primer layer are mixed evenly, coated on the silicone surface layer and the substrate is placed on the coating layer, then heated with hot air, and the release paper is peeled off after cooling to obtain the silicone leather material.

[0021] As a further optimization scheme of the present invention, the substrate is immersed in a hexamethyldisiloxane-ethanol solution, left to stand at 60° C. for 2-4 hours, and then picked up and dried, wherein the mass fraction of hexamethyldisiloxane is 1-2wt%, and the hexamethyldisiloxane-ethanol solution contains 1-2% of the mass of the solution of flame retardant thermal conductive filler.

[0022] As a further optimization scheme of the present invention, the substrate is one of PVC leather, PU leather, and polyester fabric.

[0023] The beneficial effects of the present invention are:

[0024] The flame retardant thermal conductive filler proposed in the present invention is applied to silicone leather, and has good thermal conductivity while having flame retardant effect, good mechanical properties and thermal fatigue resistance, and also good antifouling performance. Furthermore, the flame retardant thermal conductive filler proposed in the present invention has excellent dispersibility, excellent compatibility with vinyl silicone oil, methyl vinyl silicone resin, and MQ type hydrogenated silicone resin, strong interaction force, and is not easy to agglomerate. DETAILED DESCRIPTION

[0025] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0026] 1. Materials

[0027] The organic silicon leather material in the present invention is composed of a three-layer structure, which includes an organic silicon surface layer, an organic silicon base adhesive layer and a substrate from top to bottom. The substrates used in the following experiments include PVC leather, PU leather and polyester fabric.

[0028] 1.1 The silicone surface layer includes the following ingredients: vinyl silicone oil, methyl vinyl silicone resin, MQ type hydrogen-containing silicone resin, flame retardant thermal conductive filler, hydrogen-containing cross-linking agent, platinum catalyst;

[0029] 1.2 The silicone primer layer includes the following ingredients: vinyl silicone oil, methyl vinyl silicone resin, MQ type hydrogen-containing silicone resin, flame retardant thermal conductive filler, tackifier, hydrogen-containing cross-linking agent, platinum catalyst;

[0030] The vinyl silicone oil, platinum catalyst, and hexamethyldisiloxane used in the following experiments were purchased from Anhui Aiyota Silicone Oil Co., Ltd. The methylvinyl silicone resin and MQ type hydrogen-containing silicone resin used in the following experiments were purchased from Shandong Dayi Chemical Co., Ltd. The hydrogen-containing crosslinking agent used in the following experiments was purchased from Anhui Xinjia Silicone Technology Co., Ltd. The tackifier in the present invention can be an alkoxy-containing or epoxy-containing silane, and the Crosile-5626 type tackifier was used in the following experiments.

[0031] 1.3 The preparation of flame retardant thermal conductive filler includes the following steps:

[0032] (1) mixing graphene powder with a citric acid solution, wherein the mass fraction of the citric acid solution is 90±5wt%, and the amount of graphene added is 80±5g / L, adjusting the pH to 7-8 with sodium hydroxide, sealing the solution in a reactor, and performing a hydrothermal reaction at a temperature of 220±20°C for 48h. After the reaction is completed, washing the reactant with deionized water for 3 times, and drying at a low temperature (80°C) to obtain a solid;

[0033] (2) placing 95 wt% ethanol in a container, then uniformly dispersing the dried magnesium oxide powder in the ethanol, adding 2±0.05% of the weight of the magnesium oxide powder as an aminosilane coupling agent, placing the container in a water bath, heating at 95-100° C. for 10 min, placing the solution in a centrifuge after cooling, taking out a precipitate after centrifugation, and vacuum drying the precipitate to obtain a solid II;

[0034] (3) Solid 1 and solid 2 are uniformly dispersed in 95wt% ethanol at a mass ratio of 1:10-20. In the following experiments, 1:10 is used. After dispersion, the mixture is filtered and then the filtrate is subjected to solid phase heat treatment at a temperature of 700±50°C for 2h. After cooling, the solid phase is ground to obtain a flame retardant thermal conductive filler. The particle size range of the flame retardant thermal conductive filler is 50nm-1μm.

[0035] The magnesium oxide used in the following experiments was purchased from Changzhou Rongao Chemical New Materials Co., Ltd., industrial grade, purity ≥95%, and particle size range of 1-50μm; spherical alumina was purchased from Henan Dongli New Materials Co., Ltd., purity ≥99%, and particle size range of 5-20μm; antimony trioxide was purchased from Anhui Wenjia New Materials Technology Co., Ltd.; ammonium polyphosphate was purchased from Jiangsu Leien Environmental Protection Technology Co., Ltd.

[0036] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art, and the reagents and other materials used are commercially available products unless otherwise specified.

[0037] 2. Methods

[0038] 2.1 Prepare the organic silicon leather material according to the following preparation steps using the raw material composition shown in Table 1:

[0039] (1) The components of the silicone surface layer are mixed evenly to obtain a surface adhesive, the coating speed of the coating machine is set to 5 m / min, the surface adhesive is coated on the release paper using a scraper method, and then the release paper coated with the surface adhesive is placed in an oven and heated and cured in hot air at a temperature of 120±10° C. for 3±1 min to obtain a cured silicone surface layer.

[0040] (2) The substrate is immersed in an ethanol solution containing 2 wt% of a flame retardant thermal conductive filler, and after standing for a period of time, it is picked up and dried, and the components of the silicone primer layer are mixed evenly to obtain a primer. The coating speed of the coating machine is set to 5 m / min, and the primer is coated on the cured silicone surface layer using a scraper method to form a primer layer. The substrate is then placed on the primer layer, and the whole is placed in an oven and heated and cured in hot air at a temperature of 120±10°C for 3±1 min. The release paper is peeled off to obtain a silicone leather material.

[0041] Table 1. Preparation of raw materials composition

[0042]

[0043]

[0044] 2.2 A three-layer silicone leather was prepared according to the preparation method of 2.1 without adding flame-retardant and thermally conductive fillers to the silicone surface layer and the silicone base layer, as a blank group. The silicone leather material prepared above was cut into appropriate sizes as test samples and the following tests were performed:

[0045] Hardness: Shore A durometer;

[0046] Flame retardant effect: The flame retardant performance of the 2mm thick test sample was tested according to the UL94-2009 standard;

[0047] Thermal fatigue resistance: After hot air aging treatment at 120℃ for 100h, repeated three times with an interval of 24 hours each time, the thermal conductivity (ASTM / D5470) retention rate is used as the evaluation basis for thermal fatigue resistance, thermal conductivity after three aging / initial thermal conductivity × 100%;

[0048] Antifouling property of silicone surface layer: After placing each sample flat, use an oily marker to draw a 5 cm line on the surface of the sample. After standing for 24 hours, use a cloth moistened with clean water to wipe the line back and forth 5 times. Rating is performed based on the residual stains on the surface: Level 1: obvious marks, almost not removed; Level 2: obvious marks, partially removed; Level 3: shallow marks, almost removed; Level 4: marks completely removed.

[0049] The results are shown in Table 2:

[0050] Table 2. Performance parameters of silicone leather materials

[0051]

[0052] Note: The data in the present invention are averaged from multiple measurements and subjected to variance analysis.

[0053] It can be seen from the above table that the organic silicone leather prepared by the present invention has excellent flame retardant effect and good thermal conductivity, good hardness and heat fatigue resistance, and also has good anti-fouling performance.

[0054] 2.3 Based on the raw material components prepared in 2.1, the effects of different flame retardant and thermally conductive fillers, flame retardant components and thermally conductive components on the performance of silicone leather materials were studied.

[0055] (1) 95 wt% ethanol is placed in a container, and then dried magnesium oxide powder is uniformly dispersed in the ethanol, and then an aminosilane coupling agent of 2±0.05% of the weight of the magnesium oxide powder is added, and the container is placed in a water bath, and heated at 95-100° C. for 10 minutes. After cooling, the solution is placed in a centrifuge, and after centrifugation, a precipitate is taken, and the precipitate is vacuum dried to obtain a solid; the solid is dispersed in 95 wt% ethanol, and after dispersion, it is filtered, and then the filtrate is subjected to solid phase heat treatment, the heat treatment temperature is 700±50° C., the treatment time is 2 hours, and after cooling, the solid phase is ground to obtain filler 1, and the particle size range of filler 1 is 50 nm-1 μm.

[0056] (2) 95 wt% ethanol is placed in a container, and then the dried magnesium oxide powder is evenly dispersed in the ethanol, and then 2±0.05% of the weight of the magnesium oxide powder is added with an aminosilane coupling agent, and the container is placed in a water bath, and heated at 95-100° C. for 10 min. After cooling, the solution is placed in a centrifuge, and after centrifugation, the precipitate is taken out, and the precipitate is vacuum dried to obtain a solid, and the filler 2 is obtained by grinding. The particle size range of the filler 2 is 50 nm-10 μm.

[0057] (3) The dried magnesium oxide powder is uniformly dispersed in 95wt% ethanol, filtered after dispersion, and then the filtrate is subjected to solid phase heat treatment at a temperature of 700±50°C for 2h. After cooling, the solid phase is ground to obtain filler three, and the particle size range of filler three is 1-20μμm.

[0058] (4) 95wt% ethanol is placed in a container, and then the dried magnesium oxide powder is uniformly dispersed in the ethanol, and then 2±0.05% of the weight of the magnesium oxide powder is added. An aminosilane coupling agent is placed in a water bath, and heated at 95-100°C for 10 minutes. After cooling, the solution is placed in a centrifuge, and after centrifugation, a precipitate is taken, and the precipitate is vacuum dried to obtain a solid; graphene powder and solids are uniformly dispersed in 95wt% ethanol at a mass ratio of 1:10, and the mixture is filtered after dispersion, and then the filtrate is subjected to solid phase heat treatment, the heat treatment temperature is 700±50°C, the treatment time is 2h, and the solid phase is ground after cooling to obtain filler four, and the particle size range of filler four is 50nm-1μm.

[0059] Replace the flame retardant thermal conductive filler in 2.1 according to the components in the following table, and prepare a control group according to the steps in 2.1:

[0060] Table 3. Composition of the control group

[0061]

[0062]

[0063] The silicone leather material of the control group was cut into appropriate sizes as test samples, and the samples were tested according to the test method in 2.2. The results are shown in the following table:

[0064] Table 4. Performance test results of each control group

[0065]

[0066] It can be seen from the above table that the use of spherical alumina or magnesium oxide can improve the hardness, flame retardancy and thermal conductivity of silicone leather materials to a certain extent, but it will affect its thermal fatigue resistance. After adding flame retardants antimony trioxide and ammonium polyphosphate, the flame retardant effect is improved, but other effects are still mediocre. It is speculated that this is because the flame retardants, spherical alumina or magnesium oxide have poor compatibility with vinyl silicone oil, methyl vinyl silicone resin, and MQ type hydrogenated silicone resin. Through the performance test results of filler 1, filler 2, filler 3, and filler 4, it can be seen that only modifying magnesium oxide cannot significantly increase the overall thermal conductivity, flame retardancy and other properties, and may have the opposite effect. Only after mixing with graphene can the performance be significantly improved, and after the graphene is treated with citric acid, the effect of the material is greatly improved. It is speculated that this may be because magnesium oxide is loaded on graphene, forming a very stable structure with each other, and may have the generation of graphene quantum dots, which makes the flame retardant thermal conductive filler have excellent dispersibility and good compatibility with vinyl silicone oil, methyl vinyl silicone resin, and MQ type hydrogenated silicone resin.

[0067] 2.4 Based on the raw material components prepared in 2.1, the effects of different substrates on the performance of silicone leather materials were studied.

[0068] (1) PVC leather is immersed in a hexamethyldisiloxane-ethanol solution, wherein the mass fraction of hexamethyldisiloxane is 1.2 wt %, and then 2 wt % of the mass of the solution of flame retardant thermal conductive filler is dispersed in the hexamethyldisiloxane-ethanol solution, and the leather is allowed to stand at 60° C. for 2±0.5 h, and then the leather is picked up and dried to obtain a substrate 1.

[0069] (2) The PU leather is immersed in a hexamethyldisiloxane-ethanol solution, wherein the mass fraction of the hexamethyldisiloxane is 1.2 wt %, and then 2 wt % of the solution mass of a flame retardant thermal conductive filler is dispersed in the hexamethyldisiloxane-ethanol solution, and the leather is allowed to stand at 60° C. for 2±0.5 h, and then the leather is picked up and dried to obtain a substrate 2.

[0070] (3) The polyester fabric is immersed in a hexamethyldisiloxane-ethanol solution, wherein the mass fraction of hexamethyldisiloxane is 1.2 wt %, and then 2 wt % of the solution mass of a flame retardant thermal conductive filler is dispersed in the hexamethyldisiloxane-ethanol solution, and the fabric is allowed to stand at 60° C. for 2±0.5 h, and then the fabric is picked up and dried to obtain a substrate three.

[0071] Replace the substrate in 2.1 according to the components in the following table and prepare the test group according to the steps in 2.1:

[0072] Table 5. Test group composition table

[0073]

[0074] The silicone leather material of the above test group was cut into suitable sizes as test samples, and the samples were tested according to the test method in 2.2. The results are shown in the following table:

[0075] Table 6. Performance test results of each test group

[0076]

[0077] It can be seen from the above table that the substrate modified with hexamethyldisiloxane can further improve the thermal conductivity of the silicone leather material.

[0078] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A 3C electronic silicone leather material, comprising a silicone surface layer, a silicone primer layer and a substrate, wherein the silicone surface layer and the silicone primer layer both comprise the following ingredients: vinyl silicone oil, methyl vinyl silicone resin, MQ type hydrogen-containing silicone resin, a hydrogen-containing crosslinking agent, and a platinum catalyst, and the silicone primer layer further comprises a tackifier; It is characterized in that The components of the organic silicon surface layer and the organic silicon base layer also include flame retardant thermal conductive filler, and the flame retardant thermal conductive filler is obtained by mixing magnesium oxide with graphene after being modified by a silane coupling agent and then subjected to heat treatment; The added amount of the flame retardant heat conductive filler accounts for 10-20% of the total mass of the raw materials for preparing the organic silicon surface layer or the organic silicon base adhesive layer.

2. A 3C electronic silicone leather material according to claim 1, characterized in that: The preparation of the flame retardant thermal conductive filler comprises the following steps: (1) mixing graphene powder with citric acid solution, adjusting the pH to alkaline, performing a hydrothermal reaction, washing and drying the reactant, and obtaining a solid; (2) uniformly dispersing the dried magnesium oxide powder in ethanol, adding a silane coupling agent, heating in a water bath, centrifuging and collecting the precipitate, and vacuum drying to obtain a solid II; (3) The solid one and the solid two are uniformly dispersed in a solvent, and the filtrate is subjected to solid phase heat treatment after filtration, and a flame retardant thermal conductive filler is obtained after grinding.

3. A 3C electronic silicone leather material according to claim 2, characterized in that: In the step (1), the mass fraction of the citric acid solution is 85-95wt%, the amount of graphene added is 50-100g / L, the pH is adjusted to 7-8 using sodium hydroxide, and then the solution is sealed in a reactor.

4. A 3C electronic silicone leather material according to claim 3, characterized in that: In the step (1), the temperature of the hydrothermal reaction is 200-240° C., and the reaction time is 12-48 hours.

5. The 3C electronic silicone leather material according to claim 2, characterized in that: In the step (2), the mass fraction of ethanol is 95wt%, the silane coupling agent is an aminosilane coupling agent, and the added amount of the silane coupling agent is 2-3% of the mass of the magnesium oxide powder.

6. A 3C electronic silicone leather material according to claim 5, characterized in that: In the step (2), the water bath heating temperature is 95-100° C., and the heating time is 10-20 min.

7. The 3C electronic silicone leather material according to claim 2, characterized in that: The step (3) specifically comprises: uniformly dispersing solid one and solid two in ethanol at a mass ratio of 1:10-20, filtering the mixture after dispersion, and then subjecting the filtered material to solid phase heat treatment at a heat treatment temperature of 600-800°C for a treatment time of 1-2h, and grinding the solid phase material after cooling to obtain a flame retardant thermal conductive filler.

8. A method for preparing the 3C electronic silicone leather material according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) mixing the components of the silicone surface layer uniformly, coating it on a release paper and heating it with hot air; (2) The substrate is immersed in an ethanol solution containing a flame retardant thermal conductive filler, left to stand for a period of time and then picked up and dried, the components of the silicone primer layer are mixed evenly, coated on the silicone surface layer and the substrate is placed on the coating layer, then heated with hot air, and the release paper is peeled off after cooling to obtain the silicone leather material.

9. The method for preparing a 3C electronic silicone leather material according to claim 8, characterized in that: The substrate is immersed in a hexamethyldisiloxane-ethanol solution, allowed to stand at 60° C. for 2-4 hours, and then picked up and dried, wherein the mass fraction of hexamethyldisiloxane is 1-2wt%, and the hexamethyldisiloxane-ethanol solution contains 1-2% of the mass of the solution of flame retardant thermal conductive filler.

10. The method for preparing a 3C electronic silicone leather material according to claim 8, characterized in that: The base material is one of PVC leather, PU leather and polyester fabric.

Images