Antifouling self-healing backplane for electronic device and preparation method thereof

Abstract

The application belongs to the technical field of functional polymer materials, and specifically discloses an antifouling self-repairing backboard for electronic equipment and a preparation method thereof.The antifouling self-repairing backboard comprises, from bottom to top, a substrate layer, a polyurethane / carbon fiber composite layer, a water-based polyurethane finishing layer and an organic silicon antifouling self-repairing layer; the polyurethane in the polyurethane / carbon fiber composite layer is an epoxy-modified polyurethane resin; the water-based polyurethane finishing layer uses a water-based polyurethane resin modified by a Maya Blue-like attapulgite hybrid pigment; and the organic silicon antifouling self-repairing layer is an epoxy organosilane / epoxy and disulfide double-modified polyurethane composite coating.The antifouling self-repairing backboard prepared by the application has multiple functions such as antifouling, self-repairing, wear resistance, antistatic property and the like, and has the advantages of skin touch, color variety, high color fastness, good weather resistance, excellent heat conductivity, dimensional stability, green environmental protection and the like, and has a wide market prospect.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials technology, and relates to the field of electronic product backplate manufacturing, and particularly to an anti-fouling self-healing backplate for electronic devices and its preparation method. Background Technology

[0002] With the rapid development of technology and the improvement of people's living standards, electronic products have become ubiquitous in all aspects of people's lives, especially mobile phones and tablets. The back panel is a crucial component of electronic products, primarily made of glass, metal, or plastic. However, glass is brittle and has poor impact resistance, often requiring an additional protective case during use; metal, due to its inherent shielding effect, presents significant challenges to antenna design, especially with the advent of the 5G era; and plastic, due to its low strength and poor wear resistance, limits its application in large-screen displays. Furthermore, existing materials cannot self-heal from minor damage such as small scratches during the use of electronic products. Simultaneously, as consumers' aesthetic demands increase, traditional glass, metal, or plastic casings are failing to appeal to consumers in terms of both appearance and feel. Therefore, there is an urgent need to develop a new type of electronic product back panel material that is aesthetically pleasing, has a superior feel, and is impact-resistant, wear-resistant, scratch-resistant, stain-resistant, and capable of self-healing from minor scratches. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention aims to provide a self-healing anti-fouling backplate for electronic devices and its preparation method. The self-healing anti-fouling backplate uses a polymer thin plate as the base layer, epoxy-modified polyurethane resin / carbon fiber cloth as the composite layer, water-based polyurethane resin modified with Mayan blue attapulgite hybrid pigment as the surface layer, and epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating as the anti-fouling and self-healing layer. It has multiple functions such as scratch resistance, wear resistance, anti-fouling, and self-healing. Moreover, the backplate material prepared by the present invention has the advantages of bright color, high color fastness, good dimensional stability, excellent thermal conductivity, skin-like feel, and green environmental protection, and has broad market prospects.

[0004] This invention is achieved through the following technical solution: A method for preparing a self-healing anti-fouling backplate for electronic devices includes the following steps: Step 1: Add nano-kaolin, color paste, defoamer, and leveling agent to the waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment. After stirring evenly, a waterborne polyurethane surface layer slurry is obtained. It is then coated onto the surface of textured or patterned release paper using a two-roll calender and dried in an oven to form a waterborne polyurethane decorative layer. Step 2: After impregnating the carbon fiber cloth in epoxy-modified polyurethane resin, a polyurethane / carbon fiber cloth composite layer is obtained. The water-based polyurethane finishing layer and the substrate layer obtained in Step 1 are respectively bonded to both sides of the composite layer. After drying in an oven, the release paper is peeled off to form a semi-finished product. Step 3: Apply an epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating mixed with a long-chain alkyl diamine curing agent to the surface of the water-based polyurethane finishing layer obtained in Step 2, and dry it in an oven to obtain the anti-fouling self-healing backplate for electronic devices.

[0005] A further improvement to the present invention is as follows: The preparation steps of the epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating are as follows: At room temperature, a certain proportion of diglycidyl ether-terminated polydimethylsiloxane and a polyurethane prepolymer modified with both glycidyl ether and disulfide are mixed and stirred until homogeneous to obtain an epoxy organosilane / epoxy and disulfide-modified polyurethane composite coating.

[0006] Furthermore, the mass ratio of the diglycidyl ether-terminated polydimethylsiloxane and the polyurethane prepolymer modified with both glycidyl ether and disulfide is 1:3-10.

[0007] Furthermore, the preparation steps of the waterborne polyurethane resin modified with the Maya blue attapulgite hybrid pigment are as follows: Isophorone diisocyanate, hexamethylene diisocyanate, and polytetrahydrofuran ether diol were stirred and reacted at 80-90℃ for 1-2 hours. Then, 2,2'-dihydroxydiethylamine and Maya blue attapulgite hybrid pigment were added, and the reaction was continued for 0.5-1.5 hours. Then, an organic bismuth catalyst and acetone were added, and the reaction was continued for 1-2 hours. Then, a neutralization reaction was carried out at 40-60℃ using a small molecule acid neutralizer. Next, water was added and stirred at high speed to achieve self-emulsification and dispersion. Then, a small molecule diamine chain extender was added, and the temperature was raised to 40-50℃ for chain extension for 3-5 hours. Finally, the acetone was removed under low pressure at 40-60℃ to obtain a waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment.

[0008] Furthermore, the organic bismuth catalyst is selected from bismuth laurate and bismuth isooctanoate; And / or, the small molecule acid neutralizing agent is selected from hydrochloric acid, acetic acid, or sulfonic acid; And / or, the small molecule diamine chain extender is selected from ethylenediamine and isophorone diamine; And / or, the mass ratio of isophorone diisocyanate, hexamethylene diisocyanate, polytetrahydrofuran ether diol, 2,2'-dihydroxydiethylamine, Maya blue attapulgite hybrid pigment, organobismuth catalyst, acetone, small molecule acid neutralizer, and small molecule diamine chain extender is 1:0.8-1.2:1.6-2.0:0.2-0.6:0.2-0.5:0.02-0.05:1-1.5:0.1-0.3:0.2-0.5.

[0009] Furthermore, the preparation steps of the Maya blue attapulgite hybrid pigment are as follows: Take an organic pigment with an organic pigment and attapulgite at a mass ratio of 1:10, mix them evenly, put them in an oven to dry, take them out and cool them to room temperature, disperse them in water, centrifuge them and disperse the precipitate in isopropanol, then add tetraethyl orthosilicate and hydrochloric acid, react at 70-90 ℃ for 20-30 h, cool them to room temperature and filter them, wash them with isopropanol, freeze dry them at -30--10 ℃ to obtain a silica-encapsulated and modified Maya blue attapulgite hybrid pigment rich in silanol groups.

[0010] Furthermore, the long-chain alkyl diamine curing agent is a 1,12-diaminododecane curing agent.

[0011] Furthermore, the substrate layer (4) is a thin sheet material prepared by mixing one or more of polycarbonate, polymethyl methacrylate, polypropylene, polyethylene, polyamide, polybutylene terephthalate, and acrylonitrile-butadiene-styrene copolymer.

[0012] A further improvement of the present invention is as follows: The anti-fouling self-healing backplate for electronic devices prepared by the above method comprises, from top to bottom, an organosilicon anti-fouling self-healing layer (1), a waterborne polyurethane finishing layer (2), a polyurethane / carbon fiber cloth composite layer (3), and a substrate layer (4); wherein, the organosilicon anti-fouling self-healing layer (1) is an epoxy organosilicon / epoxy and disulfide dual-modified polyurethane composite coating, the waterborne polyurethane finishing layer (2) is a waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment, and the polyurethane in the polyurethane / carbon fiber cloth composite layer (3) is an epoxy-modified polyurethane resin.

[0013] Compared with the prior art, the specific beneficial effects of the present invention are as follows: 1. The present invention provides a self-healing anti-fouling backplate for electronic devices, which incorporates a polyurethane / carbon fiber cloth composite layer. First, the epoxy resin-modified polyurethane not only provides excellent adhesion between the polymer and the carbon fiber cloth, but also effectively bonds the substrate layer and the water-based polyurethane surface layer. Second, the toughness and strength of the carbon fiber cloth effectively prevent shrinkage and deformation of the mixed material layer caused by the different coefficients of thermal expansion of the materials due to temperature differences in the operating environment, thus providing excellent dimensional stability for the backplate material. Finally, carbon fiber is lightweight and has good thermal and electrical conductivity; the introduction of the polyurethane / carbon fiber cloth composite layer effectively improves the thermal conductivity and antistatic properties of the backplate. 2. The present invention provides a self-healing anti-fouling backplate for electronic devices. First, textures or patterns are introduced on the water-based polyurethane surface layer modified with Mayan blue attapulgite hybrid pigment using release paper as a template to enhance aesthetics. Second, the modification of the Mayan blue attapulgite hybrid pigment gives the backplate material surface excellent weather resistance and beautiful color, further enhancing aesthetics. 3. The present invention provides a self-healing anti-fouling backplate for electronic devices, using an epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating as the organosilicone anti-fouling self-healing layer. First, the diglycidyl ether-terminated polydimethylsiloxane, glycidyl ether, and disulfide dual-modified polyurethane prepolymer, after polymerization under the action of a long-chain alkyl diamine curing agent, provides the finishing material with excellent anti-fouling, scratch-resistant, and self-healing functions. Second, the introduction of the long-chain alkyl amine curing agent harmonizes the hardness and feel of the anti-fouling layer, improving its skin-feel. Finally, all raw materials contain epoxy groups, which improves the adhesion strength between the anti-fouling layer and the polyurethane surface layer, thereby increasing its service life. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the anti-fouling self-healing backplate for electronic devices prepared according to the present invention. Among them, (1) is an organosilicon antifouling self-healing layer; (2) is a water-based polyurethane surface layer; (3) is a polyurethane / carbon fiber cloth composite layer; and (4) is a substrate layer. Detailed Implementation

[0015] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments. Example 1

[0016] This embodiment provides a self-healing anti-fouling backplate for electronic devices and its preparation method. From top to bottom, an organosilicon self-healing layer (1), a waterborne polyurethane finishing layer (2), a polyurethane / carbon fiber composite layer (3), and a substrate layer (4) are arranged sequentially. The organosilicon self-healing layer (1) is an epoxy organosilicon / epoxy modified polyurethane composite coating, the waterborne polyurethane finishing layer (2) uses waterborne polyurethane resin modified with Mayan blue attapulgite hybrid pigment, and the polyurethane used in the polyurethane / carbon fiber composite layer (3) is an epoxy modified polyurethane resin.

[0017] This embodiment also provides a method for preparing a skin-feeling, stain-resistant decorative material for mobile phone back panels, the specific steps of which are as follows: Step 1: Add nano-kaolin, color paste, defoamer, leveling agent, etc. to the waterborne polyurethane resin modified with Mayan blue attapulgite hybrid pigment. After stirring evenly, a waterborne polyurethane surface layer slurry is obtained. It is then coated onto the surface of textured or patterned release paper through a two-roll calender and dried in a 120℃ oven to form a waterborne polyurethane surface layer. Step 2: After impregnating the carbon fiber cloth in epoxy-modified polyurethane resin, the water-based polyurethane surface layer and substrate layer obtained in Step 1 are respectively bonded to both sides. After drying in an oven at 120°C, the release paper is peeled off to form a semi-finished product. Step 3: Coat the surface of the waterborne polyurethane surface layer of the semi-finished product obtained in Step 2 with an epoxy organosilane / epoxy modified polyurethane composite coating mixed with a long-chain alkyl diamine curing agent. After baking in an oven at 100°C for 5 minutes, the anti-fouling self-healing backplate for electronic devices is obtained.

[0018] It should be noted that the specific preparation method of the above-mentioned epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating is as follows: At room temperature, 6 g of diglycidyl ether-terminated polydimethylsiloxane and 40 g of glycidyl ether and disulfide-modified polyurethane prepolymer were mixed and stirred until homogeneous. Then, 4 g of long-chain alkyl diamine curing agent was added and stirred until dissolved to obtain an epoxy organosilane / epoxy and disulfide-modified polyurethane composite coating.

[0019] The specific preparation method of the above-mentioned Mayan blue attapulgite hybrid pigment is as follows: Take 2g of organic pigment and 20g of attapulgite, mix them thoroughly, and then put them in an oven at 130 ℃ for 48 h. After cooling to room temperature, disperse them in 200 ml of water, centrifuge, disperse the precipitate in 100 ml of isopropanol, add 0.4g of tetraethyl orthosilicate and 0.2 ml of hydrochloric acid, react at 80 ℃ for 24 h, cool to room temperature, filter, wash with isopropanol, and freeze-dry at -20 °C to obtain silica-encapsulated Maya blue-like hybrid pigment rich in silanol hydroxyl groups.

[0020] The specific preparation method of the above-mentioned waterborne polyurethane resin modified with Mayan blue attapulgite hybrid pigment is as follows: 14 g of isophorone diisocyanate, 14 g of hexamethylene diisocyanate, and 26 g of polytetrahydrofuran ether diol were stirred at 85 °C for 1.5 hours. 6 g of 2,2'-dihydroxydiethylamine and 5 g of Maya blue attapulgite hybrid pigment were added, and the reaction was continued for 1 hour. Then, 0.5 g of organic bismuth catalyst and 16 g of acetone were added, and the reaction was continued for 1.5 hours. The mixture was then neutralized at 50 °C with 3 g of small molecule acid neutralizer for 0.5 hours. Next, 100 g of water was added and stirred at high speed to self-emulsify and disperse the mixture. Then, 5 g of small molecule diamine chain extender was added, and the mixture was heated to 45 °C for chain extension for 4 hours. Finally, the mixture was deacetone-modified at 50 °C under low pressure to obtain a waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment. Example 2

[0021] This embodiment is largely the same as Embodiment 1, except that the formulation of the epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating used in the organosilicon antifouling self-healing layer (1) in this embodiment is different. Specifically, at room temperature, 10 g of diglycidyl ether-terminated polydimethylsiloxane and 36 g of glycidyl ether and disulfide dual-modified polyurethane prepolymer are mixed and stirred evenly. Then, 4 g of long-chain alkyl diamine curing agent is added and stirred to dissolve, thus obtaining the epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating.

[0022] Apart from the above, this embodiment is exactly the same as Embodiment 1, and will not be described again here. Example 3

[0023] This embodiment is largely the same as Embodiment 1, except that the formulation of the Maya blue attapulgite hybrid pigment used in the waterborne polyurethane surface layer (2) in this embodiment is different. Specifically, 2g of organic pigment and 20g of attapulgite are mixed and thoroughly mixed. After mixing, the mixture is placed in an oven at 130°C for 48 hours. After cooling to room temperature, it is dispersed in 200ml of water. After centrifugation, the precipitate is dispersed in 100ml of isopropanol. Then, 0.3g of tetraethyl orthosilicate, 0.2g of tetraethoxysilane oligomer and 0.2ml of hydrochloric acid are added. The mixture is reacted at 80°C for 24 hours. After cooling to room temperature, it is filtered, washed with isopropanol, and freeze-dried at -20°C to obtain a silica-encapsulated Maya blue hybrid pigment rich in silanol hydroxyl groups.

[0024] Apart from the above, this embodiment is exactly the same as Embodiment 1, and will not be described again here.

[0025] The anti-fouling self-healing backplates for electronic devices prepared using embodiments 1 to 3 described above have a soft, elastic surface, good skin-like feel and hydrophobicity, and excellent stain resistance and abrasion resistance. The methods for testing the hydrophobicity, stain resistance, and abrasion resistance of the prepared anti-fouling self-healing backplates for electronic devices are as follows: Hydrophobicity: The hydrophobicity of the anti-fouling self-healing backplate for electronic devices is measured by the water contact angle. A 5.0 μL drop of deionized water is placed on the material surface and measured using a JC2000C2 contact angle measuring instrument. The contact angle is measured at different positions on the backplate using the goniometric method, and the average value is taken.

[0026] Stain resistance: Refer to JG / T304-2011 to test the stain resistance of the self-healing back panel surface of electronic devices; draw a circle on the back panel surface with a marker, then wipe it off with a lint-free cotton cloth, which is one cycle test (counts as one time), to test its stain resistance against marker writing, until the oil-based marker marks cannot be wiped clean.

[0027] Abrasion resistance: The number of wear cycles required for the surface of the prepared electronic device to begin to wear down using an H22 grinding wheel on a TABER friction tester with an anti-fouling self-healing backplate was tested.

[0028] The anti-fouling self-healing backplates for electronic devices prepared in Examples 1 to 3 were tested for water contact angle, stain resistance, and abrasion resistance. The results are shown in the table below:

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-healing anti-fouling backplate for electronic devices, characterized in that, Includes the following steps: Step 1: Add nano-kaolin, color paste, defoamer, and leveling agent to the waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment. After stirring evenly, a waterborne polyurethane surface layer slurry is obtained. It is then coated onto the surface of textured or patterned release paper using a two-roll calender and dried in an oven to form a waterborne polyurethane decorative layer. Step 2: After impregnating the carbon fiber cloth in epoxy-modified polyurethane resin, a polyurethane / carbon fiber cloth composite layer is obtained. The water-based polyurethane finishing layer and the substrate layer obtained in Step 1 are then bonded to both sides of the composite layer. After drying in an oven, the release paper is peeled off to form a semi-finished product. Step 3: Coat the surface of the waterborne polyurethane finishing layer obtained in Step 2 with an epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating mixed with a long-chain alkyl diamine curing agent, and dry it in an oven to obtain the anti-fouling self-healing backplate for electronic devices. The preparation steps of the Maya blue attapulgite hybrid pigment are as follows: Take an organic pigment with an attapulgite mass ratio of 1:10 and mix it with the attapulgite. After mixing evenly, put it in an oven to dry. After taking it out and cooling it to room temperature, disperse it in water. After centrifugation, disperse the precipitate in isopropanol. Then add tetraethyl orthosilicate and hydrochloric acid. React at 70-90 ℃ for 20-30 h. After cooling to room temperature, filter it, wash it with isopropanol, and freeze-dry it at -30--10 ℃ to obtain a silica-encapsulated and modified Maya blue hybrid pigment rich in silanol groups. The preparation steps of the epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating are as follows: At room temperature, a certain proportion of diglycidyl ether-terminated polydimethylsiloxane, glycidyl ether and disulfide dual-modified polyurethane prepolymer are mixed and stirred until uniformly mixed to obtain the epoxy organosilane / epoxy and disulfide dual-modified polyurethane composite coating; the mass ratio of the diglycidyl ether-terminated polydimethylsiloxane and the glycidyl ether and disulfide dual-modified polyurethane prepolymer is 1:3-10. The preparation steps of the waterborne polyurethane resin modified with the Maya blue attapulgite hybrid pigment are as follows: Isophorone diisocyanate, hexamethylene diisocyanate, and polytetrahydrofuran ether diol were stirred and reacted at 80-90℃ for 1-2 hours. Then, 2,2'-dihydroxydiethylamine and Maya blue attapulgite hybrid pigment were added, and the reaction was continued for 0.5-1.5 hours. An organic bismuth catalyst and acetone were added, and the reaction was continued for 1-2 hours. Then, a neutralization reaction was carried out at 40-60℃ using a small molecule acid neutralizer. Next, water was added and stirred at high speed for self-emulsification and dispersion. Then, a small molecule diamine chain extender was added, and the temperature was raised to 40-50℃ for chain extension for 3-5 hours. Finally, at 40-60℃, acetone was removed under low pressure to obtain a waterborne polyurethane resin modified with Maya blue attapulgite hybrid pigment. The small molecule acid neutralizer was selected from hydrochloric acid, acetic acid, or sulfonic acid; the small molecule diamine chain extender was selected from ethylenediamine and isophorone diamine. The long-chain alkyl diamine curing agent is a 1,12-diaminododecane curing agent.

2. The method for preparing a self-healing anti-fouling backplate for electronic devices according to claim 1, characterized in that: The organic bismuth catalyst is selected from bismuth laurate and bismuth isooctanoate; And / or, the mass ratio of isophorone diisocyanate, hexamethylene diisocyanate, polytetrahydrofuran ether diol, 2,2'-dihydroxydiethylamine, Maya blue attapulgite hybrid pigment, organobismuth catalyst, acetone, small molecule acid neutralizer, and small molecule diamine chain extender is 1:0.8-1.2:1.6-2.0:0.2-0.6:0.2-0.5:0.02-0.05:1-1.5:0.1-0.3:0.2-0.

5.

3. The method for preparing a self-healing anti-fouling backplate for electronic devices according to claim 1, characterized in that: The substrate layer (4) is a thin sheet material prepared by mixing one or more of polycarbonate, polymethyl methacrylate, polypropylene, polyethylene, polyamide, polybutylene terephthalate, and acrylonitrile-butadiene-styrene copolymer.

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