Electronic product shell based on PU coating and preparation method thereof

Abstract

The invention relates to the technical field of electronic products, and provides an electronic product shell based on a PU coating and a preparation method of the electronic product shell based on the PU coating, one of a glass fiber plate and a PC plate is used as a substrate, an organic silicon coating and a PU coating are sequentially sprayed on the surface of the substrate in a spraying mode, and the electronic product shell with the ageing-resistant, corrosion-resistant, wear-resistant and super-hydrophobic surface is constructed; modified zirconium phosphate is introduced into the organic silicon coating and the PU coating to serve as filler; according to the organic silicon modified waterborne polyurethane, polytetrahydrofuran, hydroxyl-terminated polydimethylsiloxane and isophorone diisocyanate are used as raw materials, a prepolymer is synthesized under the catalysis of dibutyltin dilaurate, 2, 2-bis (hydroxymethyl) propionic acid is used as a hydrophilic chain extender, pentaerythritol triacrylate is used as a photocuring active component, and the organic silicon modified waterborne polyurethane is prepared through a one-step method. A benzophenone quaternary ammonium salt compound is used as an end-capping reagent, triethanolamine is used as a neutralizer, and deionized water is added for emulsification to prepare the organic silicon modified waterborne polyurethane.

Description

Technical Field

[0001] The invention relates to the technical field of electronic products, and in particular to a PU-coated electronic product housing and a preparation method thereof. Background Art

[0002] With the development of society, various electronic products have gradually become necessities in people's lives, and consumers have higher standards for the functions and appearance of various electronic products.

[0003] Most existing electronic products use metal or plastic as shell materials. For example, in the preparation of plastic shells, the traditional method is to first form the PU leather and then paste it onto the fiberglass board or PC board. There are problems such as a relatively complicated process. Spraying the PU coating directly on the fiberglass board / PC board can simplify the process, but the prepared shell also has limited protective properties such as wear resistance, aging resistance, and waterproofness, and cannot provide long-term protection for electronic products. Summary of the invention

[0004] The object of the present invention is to provide an electronic product housing based on PU coating and a preparation method thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for preparing an electronic product housing based on PU coating comprises the following steps: S1: Preparation of silicone coating using epoxy resin, epoxy-terminated silicone and modified zirconium phosphate; S2: soaking the substrate in an ethanol solution of Michaelis acid for acidification treatment, then spraying an organic silicon coating on the surface of the substrate, and drying to obtain a pretreated substrate; S3: Preparation of PU coatings using modified zirconium phosphate, silicone-modified waterborne polyurethane, and photoinitiator; S4: Spraying the PU coating on the surface of the pretreated substrate and photocuring the coating to obtain an electronic product housing based on the PU coating.

[0006] Furthermore, the substrate is one of a glass fiber board and a PC board.

[0007] Furthermore, the working conditions of the acidification treatment are: temperature of 28-38°C and time of 2-3h.

[0008] Furthermore, the mass ratio of modified zirconium phosphate, epoxy resin and epoxy-terminated silicone is 2:25:15.

[0009] Further, the preparation of the organosilicon coating comprises the following steps: (1) Mix hydroxy silicone oil and 3-(2,3)-glycidoxypropylmethyldimethoxysilane, heat to 88-92°C and keep warm for 5-6 hours, and distill under reduced pressure to obtain epoxy-terminated silicone; (2) The modified zirconium phosphate, epoxy resin and epoxy-terminated silicone are mixed, the temperature is raised to 138-142°C and kept at this temperature for 3-4 hours, deionized water and acetic acid are added, the temperature is kept at this temperature for another 3-4 hours, dibutyltin dilaurate is added, the temperature is kept at this temperature for 4-5 hours, a curing agent is added, and the material is cooled and discharged to obtain a silicone coating.

[0010] Furthermore, the composition of the PU coating is, by weight: 1-5 parts of modified zirconium phosphate, 18-33 parts of silicone-modified waterborne polyurethane, and 0.1-0.2 parts of photoinitiator.

[0011] Further, the preparation of modified zirconium phosphate comprises the following steps: 1) Mix deionized water and phosphoric acid, add zirconium oxychloride octahydrate, transfer to a hydrothermal kettle, heat to 190-200°C and keep warm for 4-5 hours, wash, centrifuge and dry to obtain α-zirconium phosphate nanosheets; 2) 3-(2,3)-glycidoxypropylmethyldimethoxysilane, ethanol and deionized water were mixed, the pH value of the solution was adjusted to 3.9-4.1, stirred for 1-2 hours, α-zirconium phosphate nanosheets were added, stirred for 22-24 hours, centrifuged, washed and dried to obtain epoxidized zirconium phosphate; 3) Mix the quaternary ammonium salt of benzophenone, epoxidized zirconium phosphate and chloroform, add Amberlyst-15 ion exchange resin, transfer to an ultrasonic water bath, heat to 58-62°C and keep warm for 2-3 hours, filter and rotary evaporate to obtain modified zirconium phosphate.

[0012] Further, the preparation of the silicone-modified waterborne polyurethane comprises the following steps: Mix polytetrahydrofuran, hydroxy-terminated polydimethylsiloxane and acetone, add isophorone diisocyanate, 2,2-bis(hydroxymethyl)propionic acid and dibutyltin dilaurate, heat to 68-72°C and keep warm for 3-4h, add pentaerythritol triacrylate and acetone, heat to 78-82°C and keep warm for 3-4h, add benzophenone quaternary ammonium salt compound and acetone, heat to 88-92°C and keep warm for 3-4h, cool to 30-35°C, add triethanolamine, keep warm for 20-30min, add deionized water, emulsify for 1h, and rotary evaporate to obtain silicone-modified waterborne polyurethane with a solid content of 27-32%.

[0013] Further, the preparation of the benzophenone quaternary ammonium salt compound comprises the following steps: A. Mix 2,4-dihydroxybenzophenone, potassium carbonate and acetone, add dimethylaminoethyl chloride hydrochloride, raise the temperature to 52-56°C and keep warm for 11-12 hours, add dilute hydrochloric acid and NaOH solution in sequence, extract with ether, separate the liquids, add anhydrous sodium sulfate and dry to obtain an intermediate preparation; B. Mix the intermediate preparation and octyl bromide, raise the temperature to 118-122°C and keep it for 3-4 hours, cool it, recrystallize it in ethyl acetate for 3-5 times, and filter it to obtain a benzophenone quaternary ammonium salt compound.

[0014] Furthermore, the working conditions of the light curing treatment are: using a 1kW high-pressure mercury lamp, a distance of 25cm, and a time of 20s.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an electronic product shell based on PU coating and a preparation method thereof. Through component and process optimization, a glass fiber board and a PC board are used as a substrate, and an organic silicon coating and a PU coating are sprayed on the surface of the substrate in sequence by spraying, so as to construct an electronic product shell with an aging-resistant, corrosion-resistant, wear-resistant and super-hydrophobic surface.

[0016] In order to improve the corrosion resistance of the shell and prevent the prepared coating from having problems such as cracks and gaps, the present invention introduces layered α-zirconium phosphate with high mechanical strength, good acid and alkali resistance and high thermal stability into the organic silicon coating and the PU coating as a filler. In order to improve the uniformity of the dispersion of the α-zirconium phosphate in the coating, the α-zirconium phosphate is modified with 3-(2,3)-glycidoxypropylmethyldimethoxysilane to prepare epoxidized zirconium phosphate, and then the epoxy-hydroxyl ring is opened to graft a benzophenone quaternary ammonium salt compound, wherein the benzophenone quaternary ammonium salt compound is prepared by a two-step method using 2,4-dihydroxy-benzophenone, dimethylaminoethyl chloride hydrochloride and bromoalkane as raw materials, and while improving the hydrophobicity of the shell, it is endowed with excellent UV resistance, thereby improving the aging resistance of the shell.

[0017] In order to improve the adhesion between the PU coating and the substrate, the substrate is first acidified, and then a room temperature curable silicone coating is coated on the surface of the substrate. Epoxy-terminated silicone is prepared using hydroxy silicone oil and 3-(2,3)-glycidoxypropylmethyldimethoxysilane. Then, the epoxy group is subjected to ring-opening polymerization and mixed with modified zirconium phosphate and epoxy resin. Polyamide is used as a curing agent to prepare a silicone coating with good flexibility, high toughness and strong adhesion, thereby greatly improving the weather resistance of the shell.

[0018] In the present invention, modified zirconium phosphate, silicone-modified waterborne polyurethane and photoinitiator are used to prepare PU coating, which is sprayed on the surface of a pretreated substrate and subjected to photocuring treatment to obtain a super-hydrophobic surface with good aging resistance, strong corrosion resistance and good wear resistance, thereby improving the protection of electronic products.

[0019] The organosilicon-modified waterborne polyurethane is prepared by using polytetrahydrofuran, hydroxy-terminated polydimethylsiloxane and isophorone diisocyanate as raw materials, synthesizing the prepolymer under the catalysis of dibutyltin dilaurate, using 2,2-bis(hydroxymethyl)propionic acid as a hydrophilic chain extender, pentaerythritol triacrylate as a photocuring active ingredient, benzophenone quaternary ammonium salt compound as a capping agent, triethanolamine as a neutralizing agent, and adding deionized water for emulsification to prepare the organosilicon-modified waterborne polyurethane; at the same time, the introduction of benzophenone quaternary ammonium salt compound improves its photocuring rate and effect, thereby improving the antibacterial, wear resistance and corrosion resistance of the shell surface, greatly extending the service life of the shell. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, and back, the directional indication is only used to explain a specific posture such as the relative position relationship between the components, the movement status, etc. If the specific posture changes, the directional indication will also change accordingly. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0022] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0023] Embodiment 1: A method for preparing an electronic product housing based on PU coating, comprising the following steps: S1: preparing silicone coating using epoxy resin, epoxy-terminated silicone, modified zirconium phosphate and curing agent; The modified zirconium phosphate, epoxy resin, epoxy-terminated silicone and curing agent are compounded in a mass ratio of 2:25:15:5; The preparation of silicone coatings includes the following steps: (1) Mix 7 g of hydroxy silicone oil and 1.1 g of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, heat to 88 °C and keep warm for 6 h, and distill under reduced pressure to obtain epoxy-terminated silicone; (2) 2 g of modified zirconium phosphate, 25 g of epoxy resin E-51, and 15 g of epoxy-terminated silicone were mixed, the temperature was raised to 138 °C and kept warm for 4 h, 20 mL of deionized water and 0.14 g of acetic acid were added, the temperature was kept warm for 3 h, 2 drops of dibutyltin dilaurate were added, the temperature was kept warm for 4 h, 5 g of curing agent was added, and the material was cooled and discharged to obtain a silicone coating; The preparation of the modified zirconium phosphate comprises the following steps: 1) Mix 21.6 mL of deionized water and 18.4 mL of phosphoric acid, add 4 g of zirconium oxychloride octahydrate, transfer to a hydrothermal kettle, heat to 190 ° C and keep warm for 5 hours, wash, centrifuge and dry to obtain α-zirconium phosphate nanosheets; 2) Mix 5 mL of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, 80 mL of ethanol, and 20 mL of deionized water, adjust the pH value of the solution to 3.9, stir for 1 hour, add 1 g of α-zirconium phosphate nanosheets, stir for 22 hours, centrifuge, wash, and dry to obtain epoxidized zirconium phosphate; 3) Mix 1.2 g of benzophenone quaternary ammonium salt compound, 0.7 g of epoxidized zirconium phosphate, and 5 mL of chloroform, add 0.5 g of Amberlyst-15 ion exchange resin, transfer to an ultrasonic water bath, heat to 58 ° C and keep warm for 3 h, filter, and rotary evaporate to obtain modified zirconium phosphate; The preparation of the benzophenone quaternary ammonium salt compound comprises the following steps: A. Mix 0.05 mol 2,4-dihydroxybenzophenone, 0.07 mol potassium carbonate and 50 mL acetone, add 0.1 mol dimethylaminoethyl chloride hydrochloride, raise the temperature to 52°C and keep warm for 12 hours, add dilute hydrochloric acid and NaOH solution in sequence, extract with ether, separate the liquids, add anhydrous sodium sulfate to dry, and obtain an intermediate preparation; B. Mix 1 g of the intermediate preparation and 3 g of bromooctane, heat to 118°C and keep warm for 4 hours, cool, recrystallize 3 times in ethyl acetate, and filter to obtain a benzophenone quaternary ammonium salt compound; S2: soaking the substrate in a 3wt% ethanol solution of Michaelis acid for acidification treatment, then spraying the organic silicon coating on the surface of the substrate, and drying to obtain a pretreated substrate; the substrate is a glass fiber board; The working conditions of acidification treatment were: temperature 28 °C, time 3 h; S3: Preparation of PU coatings using modified zirconium phosphate, silicone-modified waterborne polyurethane, and photoinitiator; The composition of the PU coating is, by mass, 1 part of modified zirconium phosphate, 18 parts of silicone-modified waterborne polyurethane, and 0.1 part of photoinitiator; The preparation of silicone-modified waterborne polyurethane comprises the following steps: 12g of polytetrahydrofuran, 5g of hydroxyl-terminated polydimethylsiloxane and 15mL of acetone were mixed, 14g of isophorone diisocyanate, 2g of 2,2-bis(hydroxymethyl)propionic acid and 0.2g of dibutyltin dilaurate were added, the temperature was raised to 68°C and kept for 4h, 4g of pentaerythritol triacrylate and 10mL of acetone were added, the temperature was raised to 78°C and kept for 3h, 3.2g of benzophenone quaternary ammonium salt compound and 10mL of acetone were added, the temperature was raised to 88°C and kept for 4h, the mixture was cooled to 30°C, 3.1g of triethanolamine was added, the mixture was kept for 20min, deionized water was added, the mixture was emulsified for 1h, and the mixture was rotary evaporated to obtain a silicone-modified waterborne polyurethane having a solid content of 29%; S4: Spraying the PU coating on the surface of the pretreated substrate and photocuring it to obtain an electronic product housing based on the PU coating; the working conditions of the photocuring treatment are: using a 1kW high-pressure mercury lamp, a distance of 25cm, and a time of 20s; the photoinitiator is 2,4,6-trimethylbenzoyl-xylylphosphine oxide.

[0024] Embodiment 2: A method for preparing an electronic product housing based on a PU coating, comprising the following steps: S1: preparing silicone coating using epoxy resin, epoxy-terminated silicone, modified zirconium phosphate and curing agent; The modified zirconium phosphate, epoxy resin, epoxy-terminated silicone and curing agent are compounded in a mass ratio of 2:25:15:5; The preparation of silicone coatings includes the following steps: (1) Mix 7 g of hydroxy silicone oil and 1.1 g of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, heat to 90°C and keep warm for 5.5 hours, and distill under reduced pressure to obtain epoxy-terminated silicone; (2) 2 g of modified zirconium phosphate, 25 g of epoxy resin E-51, and 15 g of epoxy-terminated silicone were mixed, the temperature was raised to 140°C and kept warm for 3.5 h, 20 mL of deionized water and 0.14 g of acetic acid were added, the temperature was kept warm for another 3.5 h, 2 drops of dibutyltin dilaurate were added, the temperature was kept warm for 4.5 h, 5 g of curing agent was added, the material was cooled and discharged, and a silicone coating was obtained; The preparation of the modified zirconium phosphate comprises the following steps: 1) Mix 21.6 mL of deionized water and 18.4 mL of phosphoric acid, add 4 g of zirconium oxychloride octahydrate, transfer to a hydrothermal reactor, heat to 195 ° C and keep warm for 4.5 hours, wash, centrifuge and dry to obtain α-zirconium phosphate nanosheets; 2) Mix 5 mL of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, 80 mL of ethanol, and 20 mL of deionized water, adjust the pH value of the solution to 4, stir for 1.5 h, add 1 g of α-zirconium phosphate nanosheets, stir for 23 h, centrifuge, wash, and dry to obtain epoxidized zirconium phosphate; 3) Weigh 1.2 g of benzophenone quaternary ammonium salt compound, 0.7 g of epoxidized zirconium phosphate, and 5 mL of chloroform, mix, add 0.5 g of Amberlyst-15 ion exchange resin, transfer to an ultrasonic water bath, heat to 60 ° C and keep warm for 2.5 h, filter, and rotary evaporate to obtain modified zirconium phosphate; The preparation of the benzophenone quaternary ammonium salt compound comprises the following steps: A. Mix 0.05 mol 2,4-dihydroxybenzophenone, 0.07 mol potassium carbonate and 50 mL acetone, add 0.1 mol dimethylaminoethyl chloride hydrochloride, raise the temperature to 53°C and keep it for 11.5 hours, add dilute hydrochloric acid and NaOH solution in sequence, extract with ether, separate the liquids, add anhydrous sodium sulfate to dry, and obtain an intermediate preparation; B. Mix 1 g of the intermediate preparation and 3 g of bromooctane, heat to 120°C and keep warm for 3.5 h, cool, recrystallize 4 times in ethyl acetate, and filter to obtain a benzophenone quaternary ammonium salt compound; S2: soaking the substrate in a 3wt% ethanol solution of Michaelis acid for acidification treatment, then spraying the organic silicon coating on the surface of the substrate, and drying to obtain a pretreated substrate; the substrate is a glass fiber board; The working conditions of acidification treatment were: temperature 35°C, time 2.5 h; S3: Preparation of PU coatings using modified zirconium phosphate, silicone-modified waterborne polyurethane, and photoinitiator; The composition of the PU coating is, by mass, 3 parts of modified zirconium phosphate, 26 parts of organosilicon-modified waterborne polyurethane, and 0.15 parts of photoinitiator; The preparation of silicone-modified waterborne polyurethane comprises the following steps: 12g of polytetrahydrofuran, 5g of hydroxyl-terminated polydimethylsiloxane and 15mL of acetone were mixed, 14g of isophorone diisocyanate, 2g of 2,2-bis(hydroxymethyl)propionic acid and 0.2g of dibutyltin dilaurate were added, the temperature was raised to 70°C and kept for 3.5h, 4g of pentaerythritol triacrylate and 10mL of acetone were added, the temperature was raised to 80°C and kept for 3.5h, 3.2g of benzophenone quaternary ammonium salt compound and 10mL of acetone were added, the temperature was raised to 90°C and kept for 3.5h, the mixture was cooled to 33°C, 3.1g of triethanolamine was added, the mixture was kept for 25min, deionized water was added, the mixture was emulsified for 1h, and the mixture was rotary evaporated to obtain a silicone-modified waterborne polyurethane having a solid content of 29%; S4: Spraying the PU coating on the surface of the pretreated substrate and photocuring it to obtain an electronic product housing based on the PU coating; the working conditions of the photocuring treatment are: using a 1kW high-pressure mercury lamp, a distance of 25cm, and a time of 20s; the photoinitiator is 2,4,6-trimethylbenzoyl-xylylphosphine oxide.

[0025] Embodiment 3: A method for preparing an electronic product housing based on PU coating, comprising the following steps: S1: preparing silicone coating using epoxy resin, epoxy-terminated silicone, modified zirconium phosphate and curing agent; The modified zirconium phosphate, epoxy resin, epoxy-terminated silicone and curing agent are compounded in a mass ratio of 2:25:15:5; The preparation of silicone coatings includes the following steps: (1) Mix 7 g of hydroxy silicone oil and 1.1 g of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, heat to 88-92°C and keep warm for 5-6 hours, and distill under reduced pressure to obtain epoxy-terminated silicone; (2) 2 g of modified zirconium phosphate, 25 g of epoxy resin E-51, and 15 g of epoxy-terminated silicone were mixed, heated to 142 °C and kept warm for 3 h, 20 mL of deionized water and 0.14 g of acetic acid were added, and the temperature was kept warm for 4 h. 2 drops of dibutyltin dilaurate were added, and the temperature was kept warm for 5 h. 5 g of curing agent was added, and the material was cooled and discharged to obtain a silicone coating; The preparation of the modified zirconium phosphate comprises the following steps: 1) Mix 21.6 mL of deionized water and 18.4 mL of phosphoric acid, add 4 g of zirconium oxychloride octahydrate, transfer to a hydrothermal kettle, heat to 200 ° C and keep warm for 4 hours, wash, centrifuge and dry to obtain α-zirconium phosphate nanosheets; 2) Mix 5 mL of 3-(2,3)-glycidoxypropylmethyldimethoxysilane, 80 mL of ethanol, and 20 mL of deionized water, adjust the pH value of the solution to 4.1, stir for 2 h, add 1 g of α-zirconium phosphate nanosheets, stir for 24 h, centrifuge, wash, and dry to obtain epoxidized zirconium phosphate; 3) Weigh 1.2 g of benzophenone quaternary ammonium salt compound, 0.7 g of epoxidized zirconium phosphate, and 5 mL of chloroform, mix, add 0.5 g of Amberlyst-15 ion exchange resin, transfer to an ultrasonic water bath, heat to 62 ° C and keep warm for 2 h, filter, and rotary evaporate to obtain modified zirconium phosphate; The preparation of the benzophenone quaternary ammonium salt compound comprises the following steps: A. Mix 0.05 mol 2,4-dihydroxybenzophenone, 0.07 mol potassium carbonate and 50 mL acetone, add 0.1 mol dimethylaminoethyl chloride hydrochloride, raise the temperature to 56°C and keep it for 11 hours, add dilute hydrochloric acid and NaOH solution in sequence, extract with ether, separate the liquids, add anhydrous sodium sulfate to dry, and obtain an intermediate preparation; B. Mix 1 g of the intermediate preparation and 3 g of bromooctane, heat to 122°C and keep warm for 3 h, cool, recrystallize 5 times in ethyl acetate, and filter to obtain a benzophenone quaternary ammonium salt compound; S2: soaking the substrate in a 3wt% ethanol solution of Michaelis acid for acidification treatment, then spraying the organic silicon coating on the surface of the substrate, and drying to obtain a pretreated substrate; the substrate is a glass fiber board; The working conditions of acidification treatment were: temperature 38°C, time 2h; S3: Preparation of PU coatings using modified zirconium phosphate, silicone-modified waterborne polyurethane, and photoinitiator; The composition of the PU coating is, by mass, 5 parts of modified zirconium phosphate, 33 parts of organosilicon-modified waterborne polyurethane, and 0.2 parts of photoinitiator; The preparation of silicone-modified waterborne polyurethane comprises the following steps: 12g of polytetrahydrofuran, 5g of hydroxyl-terminated polydimethylsiloxane and 15mL of acetone were mixed, 14g of isophorone diisocyanate, 2g of 2,2-bis(hydroxymethyl)propionic acid and 0.2g of dibutyltin dilaurate were added, the temperature was raised to 72°C and kept for 3h, 4g of pentaerythritol triacrylate and 10mL of acetone were added, the temperature was raised to 82°C and kept for 3h, 3.2g of benzophenone quaternary ammonium salt compound and 10mL of acetone were added, the temperature was raised to 92°C and kept for 3h, the mixture was cooled to 35°C, 3.1g of triethanolamine was added, the mixture was kept for 30min, deionized water was added, the mixture was emulsified for 1h, and the mixture was rotary evaporated to obtain a silicone-modified waterborne polyurethane having a solid content of 29%; S4: Spraying the PU coating on the surface of the pretreated substrate and photocuring it to obtain an electronic product housing based on the PU coating; the working conditions of the photocuring treatment are: using a 1kW high-pressure mercury lamp, a distance of 25cm, and a time of 20s; the photoinitiator is 2,4,6-trimethylbenzoyl-xylylphosphine oxide.

[0026] Comparative Example 1: Taking Example 3 as the control group, the modified zirconium phosphate was replaced by α-zirconium phosphate nanosheets, and the other processes were normal.

[0027] Comparative Example 2: Example 3 was used as a control group, in which no organosilicon coating was prepared and other processes were normal.

[0028] Comparative Example 3: Example 3 was used as a control group, in which no benzophenone quaternary ammonium salt compound was prepared, and other processes were normal.

[0029] The thickness formed by the silicone coating is 0.1 mm, and the thickness formed by the PU coating is 0.2 mm.

[0030] Sources of raw materials used (for demonstration purposes only): Glass fiber board (3mm): Dongguan Aokexing Composite Materials Products Co., Ltd.; Hydroxyl-terminated polydimethylsiloxane (99%): Wuhan Kanos Technology Co., Ltd.; Epoxy resin E-51: Wuhan Penglei Biotechnology Co., Ltd.; Amberlyst-15 ion exchange resin Y52434: Shanghai Yuanye Biotechnology Co., Ltd.; Curing agent 651: Xuzhou Jiabao Runhe New Materials Technology Co., Ltd.; Hydroxyl silicone oil (98%): Hubei Hengjingrui Chemical Co., Ltd.; Polytetrahydrofuran P118599, 3-(2,3)-glycidoxypropylmethyldimethoxysilane G134407, zirconium oxychloride octahydrate Z104931, 2,4-dihydroxy Benzophenone D110121, dimethylaminochloroethane hydrochloride D154697, bromooctane B152446, Michaelis acid M110151, isophorone diisocyanate I109582, dibutyltin dilaurate D100274, 2,2-bis(hydroxymethyl)propionic acid D165817, pentaerythritol triacrylate P192936, triethanolamine T431267, 2,4,6-trimethylbenzoyl-xylylphosphine oxide T107643: Aladdin reagent; acetic acid, phosphoric acid, ethanol, chloroform, acetone, dilute hydrochloric acid, NaOH solution, ether, anhydrous sodium sulfate, potassium carbonate, ethyl acetate, analytical grade: Sinopharm reagent.

[0031] Performance test: The shells prepared in the embodiments and comparative examples were tested: Hydrophobicity: characterized by water contact angle, tested with 3µL deionized water droplets; UV aging resistance: measured by gloss loss rate, tested with reference to GB / T9754-2007, the sample was placed in an aging box, the working conditions were: relative humidity 48%, light intensity 180W / m 2 , temperature 70°C, irradiation 2h, spray with deionized water for 18min, measure 60° gloss every 60h, and the surface gloss loss rate after irradiation for 2 weeks is (G0-G) / G0×100% (G0-initial gloss; G-gloss after aging test); wear resistance: the wear medium is AATCC standard cotton cloth, tested by a wear tester, the weight is 0.2kg, 10cm back and forth is one wear cycle, 100 cycles, and the water contact angle is measured again. The difference with the initial water contact angle is less than 1°, including 1°, which is excellent, otherwise it is unqualified; the results are shown in Table 1; Table 1 The present invention provides an electronic product shell based on PU coating and a preparation method thereof. Through component and process optimization, a glass fiber board and a PC board are used as a substrate, and an organic silicon coating and a PU coating are sprayed on the surface of the substrate in sequence by spraying, so as to construct an electronic product shell with an aging-resistant, corrosion-resistant, wear-resistant and super-hydrophobic surface. In Table 1, / indicates that the item has not been tested.

[0032] By comparing Example 3 with Comparative Example 1 and Comparative Example 3, it can be seen that in order to improve the corrosion resistance of the shell and prevent the prepared coating from having problems such as cracks and gaps, the present invention introduces a layered α-zirconium phosphate with high mechanical strength, good acid and alkali resistance and high thermal stability into the silicone coating and the PU coating as a filler. In order to improve the uniformity of the dispersion of α-zirconium phosphate in the coating, α-zirconium phosphate is modified with 3-(2,3)-glycidoxypropylmethyldimethoxysilane to prepare epoxidized zirconium phosphate, and then epoxy-hydroxyl ring opening is utilized to graft a benzophenone quaternary ammonium salt compound, wherein the benzophenone quaternary ammonium salt compound is prepared by a two-step method using 2,4-dihydroxy-benzophenone, dimethylaminoethyl chloride hydrochloride and alkyl bromide as raw materials, which improves the hydrophobicity of the shell while giving it excellent UV resistance, thereby improving the aging resistance of the shell.

[0033] By comparing Example 3 with Comparative Example 2, it can be seen that in order to improve the adhesion between the PU coating and the substrate, the substrate is first acidified, and then a room temperature curable silicone coating is coated on the surface of the substrate, and epoxy-terminated silicone is prepared using hydroxy silicone oil and 3-(2,3)-glycidoxypropylmethyldimethoxysilane, and then the epoxy group is ring-opening polymerized and blended with modified zirconium phosphate and epoxy resin, and polyamide is used as a curing agent to prepare a silicone coating with good flexibility, high toughness and strong adhesion, thereby greatly improving the weather resistance of the shell.

[0034] By comparing Example 3 with Comparative Example 3, it can be seen that the organosilicon-modified waterborne polyurethane is prepared by using polytetrahydrofuran, hydroxyl-terminated polydimethylsiloxane, and isophorone diisocyanate as raw materials, synthesizing a prepolymer under the catalysis of dibutyltin dilaurate, using 2,2-bis(hydroxymethyl)propionic acid as a hydrophilic chain extender, using pentaerythritol triacrylate as a photocurable active ingredient, using benzophenone quaternary ammonium salt compound as a capping agent, using triethanolamine as a neutralizing agent, and adding deionized water for emulsification to prepare the organosilicon-modified waterborne polyurethane; at the same time, the introduction of benzophenone quaternary ammonium salt compound improves its photocuring rate and effect, thereby improving the antibacterial, wear resistance and corrosion resistance of the shell surface, and greatly extending the service life of the shell.

[0035] The above descriptions are only embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the present invention specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an electronic product housing based on PU coating, characterized in that: The following steps are involved: S1: preparing silicone coating using epoxy resin, epoxy-terminated silicone, modified zirconium phosphate and curing agent; S2: soaking the substrate in an ethanol solution of Michaelis acid for acidification treatment, then spraying an organic silicon coating on the surface of the substrate, and drying to obtain a pretreated substrate; S3: Preparation of PU coatings using modified zirconium phosphate, silicone-modified waterborne polyurethane, and photoinitiator; S4: Spraying the PU coating on the surface of the pretreated substrate and photocuring the coating to obtain an electronic product housing based on the PU coating.

2. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The substrate is one of a glass fiber board and a PC board.

3. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The working conditions of acidification treatment are: temperature 28-38℃, time 2-3h.

4. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: In the preparation of the organosilicon coating, the mass ratio of the modified zirconium phosphate, epoxy resin, epoxy-terminated organosilicon and curing agent is 2:25:15:

5.

5. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The preparation of the organosilicon coating comprises the following steps: (1) Mix hydroxy silicone oil and 3-(2,3)-glycidoxypropylmethyldimethoxysilane, heat to 88-92°C and keep warm for 5-6 hours, and distill under reduced pressure to obtain epoxy-terminated silicone; (2) The modified zirconium phosphate, epoxy resin and epoxy-terminated silicone are mixed, the temperature is raised to 138-142°C and kept at this temperature for 3-4 hours, deionized water and acetic acid are added, the temperature is kept at this temperature for another 3-4 hours, dibutyltin dilaurate is added, the temperature is kept at this temperature for 4-5 hours, a curing agent is added, and the material is cooled and discharged to obtain a silicone coating.

6. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The composition of the PU coating is, by weight: 1-5 parts of modified zirconium phosphate, 18-33 parts of silicone-modified waterborne polyurethane, and 0.1-0.2 parts of photoinitiator.

7. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The preparation of the modified zirconium phosphate comprises the following steps: 1) Mix deionized water and phosphoric acid, add zirconium oxychloride octahydrate, transfer to a hydrothermal kettle, heat to 190-200°C and keep warm for 4-5 hours, wash, centrifuge and dry to obtain α-zirconium phosphate nanosheets; 2) 3-(2,3)-glycidoxypropylmethyldimethoxysilane, ethanol and deionized water were mixed, the pH value of the solution was adjusted to 3.9-4.1, stirred for 1-2 hours, α-zirconium phosphate nanosheets were added, stirred for 22-24 hours, centrifuged, washed and dried to obtain epoxidized zirconium phosphate; 3) Mix the quaternary ammonium salt of benzophenone, epoxidized zirconium phosphate and chloroform, add Amberlyst-15 ion exchange resin, transfer to an ultrasonic water bath, heat to 58-62°C and keep warm for 2-3 hours, filter and rotary evaporate to obtain modified zirconium phosphate.

8. The method for preparing an electronic product housing based on PU coating according to claim 1, characterized in that: The preparation of the organosilicon-modified waterborne polyurethane comprises the following steps: Mix polytetrahydrofuran, hydroxy-terminated polydimethylsiloxane and acetone, add isophorone diisocyanate, 2,2-bis(hydroxymethyl)propionic acid and dibutyltin dilaurate, heat to 68-72°C and keep warm for 3-4h, add pentaerythritol triacrylate and acetone, heat to 78-82°C and keep warm for 3-4h, add benzophenone quaternary ammonium salt compound and acetone, heat to 88-92°C and keep warm for 3-4h, cool to 30-35°C, add triethanolamine, keep warm for 20-30min, add deionized water, emulsify for 1h, and rotary evaporate to obtain silicone-modified waterborne polyurethane.

9. The method for preparing an electronic product housing based on PU coating according to claim 7 or 8, characterized in that: The preparation of the benzophenone quaternary ammonium salt compound comprises the following steps: A. Mix 2,4-dihydroxybenzophenone, potassium carbonate and acetone, add dimethylaminoethyl chloride hydrochloride, raise the temperature to 52-56°C and keep warm for 11-12 hours, add dilute hydrochloric acid and NaOH solution in sequence, extract with ether, separate the liquids, add anhydrous sodium sulfate to dry, and obtain an intermediate preparation; B. Mix the intermediate preparation and octyl bromide, raise the temperature to 118-122°C and keep it for 3-4 hours, cool it, recrystallize it in ethyl acetate for 3-5 times, and filter it to obtain a benzophenone quaternary ammonium salt compound.

10. An electronic product housing based on PU coating, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 8.

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