Surface waterproofing transfer printing process for mobile phone case based on glass fiber epoxy resin plate

Abstract

The application relates to the technical field of mobile phone shells and particularly relates to a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate. The scheme uses glass fiber cloth as a reinforcing material, coats glue solution on both sides of the glass fiber cloth, carries out multilayer hot pressing after solidification, obtains a mobile phone shell substrate, sprays a primer and a topcoat on the surface of the mobile phone shell substrate, forms texture through a transfer printing process, sprays light oil after that, covers a protective film, and obtains a surface waterproof mobile phone shell. The application discloses a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate, the process design is reasonable, the glue solution components are adjusted properly, the prepared mobile phone shell not only has excellent strength and water resistance, but also has relatively excellent mechanical properties such as compressive strength, can be widely applied to mobile phone or other electronic product shell processing, and has relatively high practicability.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of mobile phone shells, in particular to a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate. BACKGROUND

[0002] With the development of social economy, consumers have higher and higher requirements for the appearance, texture and strength of the shell of electronic equipment, therefore, the material design and process adjustment of the mobile phone shell have become the research and development project of enterprises, and the glass fiber reinforced epoxy resin composite plate is generally used as the mobile phone shell processing raw material on the market, but the conventional glass fiber reinforced epoxy resin composite plate has poor water resistance and cannot meet the actual processing requirements.

[0003] Based on the situation, the surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate is disclosed to provide a mobile phone shell with excellent water resistance and high strength, and the specific surface processing process is disclosed to solve the problems in the prior art. SUMMARY

[0004] The application aims to provide a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate to solve the problems in the background.

[0005] In order to solve the above technical problems, the application provides the following technical scheme:

[0006] The surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate comprises the following steps:

[0007] (1) vacuum dehydration of polyol for 20-30 min, mixing of the polyol with a catalyst after dehydration, uniform stirring, heating to 60-65 DEG C, slow dropwise addition of epoxy chloropropane, dropwise addition time of 2-2.5 h, preservation reaction for 6-8 h, removal of unreacted epoxy chloropropane, cooling to 40-45 DEG C, dilution with toluene, addition of solid sodium hydroxide, preservation reaction for 5-6 h, product collection by suction filtration, extraction of organic phase, washing and drying, and obtaining of branched epoxy resin;

[0008] When the polyol is ethoxylated pentaerythritol with a molecular weight of 600-800, branched epoxy resin A is obtained; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1000-1200, branched epoxy resin B is obtained;

[0009] (2) mixing of epoxy resin, branched epoxy resin A and branched epoxy resin B to obtain a compounded resin, addition of a curing agent and benzyl dimethylamine to the compounded resin, uniform stirring, and obtaining of a glue solution;

[0010] The glass fibers are arranged to dry at 100-110℃ to remove moisture, and the glue solution is coated on both sides of the glass fiber cloth, and then cured at 110-120℃ to obtain a prepreg; a plurality of prepregs are stacked and hot-pressed to obtain a mobile phone shell substrate.

[0011] (3) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure; coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, and ultraviolet cure to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and then imprint to form an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0012] In a more optimized scheme, in step (1), the molar ratio of the hydroxyl group of the polyol, the epichlorohydrin, and the solid sodium hydroxide is 1:(1.1-1.3):(1-1.1).

[0013] In a more optimized scheme, in step (2), the preparation of the curing agent is as follows:

[0014] Mix isophorone diisocyanate, compounded alcohol, and catalyst, and react under nitrogen environment for 1-2h, the reaction time is 70-75℃, and then add ethyl acetate to obtain a polyurethane prepolymer;

[0015] Mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir uniformly, cool to 5-10℃, add the polyurethane prepolymer, and react for 2-2.5h, and then distill the solvent to obtain a curing agent.

[0016] In a more optimized scheme, the compounded alcohol is a mixture of ethoxylated pentaerythritol with a molecular weight of 300-400 and ethoxylated pentaerythritol with a molecular weight of 600-800, and the mass ratio is 1:1; the mass ratio of the compounded alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:(9-10).

[0017] In a more optimized scheme, in step (2), the mass ratio of the epoxy resin E-51, the branched epoxy resin A, and the branched epoxy resin B is 3:2:1; the amount of the benzyl dimethylamine is 0.3-0.4wt% of the total amount of the compounded resin, and the mass ratio of the compounded resin and the curing agent is 3:1.

[0018] In a more optimized scheme, in step (2), when hot-pressed, the hot-pressing temperature is 130-140℃, the pressure is 5-10MPa, and the amount of glue solution coated is 150-250g / m 2 .

[0019] More optimized scheme, in step (2), the glue liquid contains fluorinated graphene and graphene oxide, the amount of fluorinated graphene is 0.5-0.8wt% of the total amount of compound resin, the amount of graphene oxide is 0.8-1wt% of the total amount of compound resin;

[0020] The surface of the fluorinated graphene and graphene oxide is treated by silane coupling agent, and the specific steps are as follows: KH-560, methanol and deionized water are mixed in a volume ratio of 5:1:1, ultrasonic dispersion is carried out for 10-20min, hydrolysis is carried out at 30-40 DEG C for 20-24h, then fluorinated graphene or graphene oxide is added, reaction is carried out at 80-85 DEG C water bath for 3-4h, centrifugal washing, freeze drying.

[0021] More optimized scheme, in the above reaction, the catalyst is dibutyltin dilaurate.

[0022] More optimized scheme, the epoxy resin is epoxy resin E-44 or epoxy resin E-51.

[0023] Compared with the prior art, the beneficial effects achieved by the present application are:

[0024] The application discloses a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate, and the process is characterized in that: glass fiber cloth is used as a reinforcing material, glue liquid is coated on both sides of the glass fiber cloth, and after curing, the mobile phone shell substrate is obtained through multi-layer hot pressing; then, primer is sprayed on one side surface of the mobile phone shell substrate and is baked and cured; the texture surface of an inner texture mold is coated with UV glue, and then the mobile phone shell substrate sprayed with primer is attached to the UV glue surface, ultraviolet curing is carried out to form an inner texture layer; PU pearl luster paint is sprayed on the surface of the inner texture layer, baking and curing are carried out, then topcoat is sprayed, baking and curing are carried out, an outer texture layer is formed through transfer printing, a protective film is covered, and CNC processing is carried out to form a mobile phone shell with a surface waterproof function; the main creation point of the application lies in the processing process of the mobile phone shell substrate; the topcoat, the primer, the protective film, the PU pearl luster paint and the UV glue involved in the subsequent process all adopt existing commercially available products, and components can be selected from acrylate, polyurethane and epoxy resin, and the specific selection can be made according to customer demand, which will not be repeated here.

[0025] In the scheme, the present application improves the glue solution component, the scheme takes ethoxylated pentaerythritol with molecular weight of 600-800 as the reaction component, reacts with epichlorohydrin to be epoxidized, thereby generating branched structure polyether epoxy resin (branched epoxy resin A), the branched epoxy resin A is cross structure, presents as branched structure; at the same time, the scheme takes ethoxylated trimethylolpropane with molecular weight of 1000-1200 as the reaction component, reacts with epichlorohydrin to be epoxidized, generates Y-shaped polyether epoxy resin of three-way structure (branched epoxy resin B), the two are compounded, introduce branched flexible molecular chain, can effectively toughen and strengthen the system to the epoxy resin, at the same time, can improve the crosslinking density of the system in subsequent crosslinking process, thereby improving the strength and comprehensive mechanical properties of the mobile phone shell matrix, and the water resistance of the product is also improved.

[0026] On this basis, the preparation method of the curing agent is adjusted, which is different from the conventional small molecule curing agent, the scheme is compounded with ethoxylated pentaerythritol with molecular weight of 300-400 and ethoxylated pentaerythritol with molecular weight of 600-800, first, the compounded alcohol is reacted with isocyanate group to introduce terminal isocyanate group, then it is reacted with small molecule amine, thereby generating flexible curing agent, in the curing agent, the scheme adjusts and adapts alcohol with different molecular weight as the reaction component, not only can ensure the reaction crosslinking, but also can further enhance the system, and the comprehensive performance of the product is more excellent.

[0027] At the same time, the scheme also adds fluorinated graphene and graphene oxide in the glue solution, which has a multi-layer sheet structure and can effectively realize barrier, and the water resistance and corrosion resistance of the product are further improved.

[0028] The present application discloses a kind of based on glass fiber epoxy resin plate material of mobile phone shell Surface Waterproofing process, process design is reasonable, glue solution component is adjusted appropriately, and the mobile phone shell prepared has not only excellent strength and water resistance, but also relatively excellent mechanical properties such as compressive strength, can be widely applied to mobile phone or other electronic product shell processing, with high practicality. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0030] In this embodiment, ethoxylated pentaerythritol with a molecular weight of 600-800: the average molecular weight is 797, and an average of 15 ethylene oxides react with each pentaerythritol molecule, PP150; ethoxylated trimethylolpropane with a molecular weight of 1000-1200: the average molecular weight is 1014, and an average of 20 ethylene oxides react with each trimethylolpropane molecule, TP200; ethoxylated pentaerythritol with a molecular weight of 300-400: the average molecular weight is 355, and an average of 5 ethylene oxides react with each pentaerythritol molecule, PP50; all of the above are provided by Perstorp AB Company in Sweden. The epoxy resin is epoxy resin E-51. The model of the glass fiber cloth is 2116, and the thickness is 0.1 mm. The fluorinated graphene has a number 100834 and a number XF096; the oxidized graphene has a number 102185 and a number XF224-1, both of which are provided by Jiangsu Xianfeng Nanometer Material.

[0031] Example 1:

[0032] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate: comprising the following steps:

[0033] (1) Take the polyol, vacuum dehydrate for 20 min, mix the polyol with the catalyst after dehydration, stir uniformly, heat to 60℃, slowly add epichlorohydrin, the dropwise adding time is 2h, keep warm for 8h, remove the unreacted epichlorohydrin, cool to 40℃, dilute with toluene, add solid sodium hydroxide and keep warm for 5h, collect the product by suction filtration, extract the organic phase, wash and dry to obtain the branched epoxy resin. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the polyol.

[0034] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, the branched epoxy resin A is obtained by reaction; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1014, the branched epoxy resin B is obtained by reaction; the molar ratio of the hydroxyl group of the polyol, epichlorohydrin and solid sodium hydroxide is 1:1.3:1.1.

[0035] (2) Take isophorone diisocyanate, compound alcohol and catalyst, mix them, react under nitrogen environment for 1h, the reaction time is 75℃, add ethyl acetate to obtain polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir uniformly, cool to 10℃, add the polyurethane prepolymer, react for 2h, distill the solvent to obtain the curing agent.

[0036] The complex alcohol is ethoxylated pentaerythritol with a molecular weight of 355, ethoxylated pentaerythritol with a molecular weight of 797, and the mass ratio is 1:1; the mass ratio of the complex alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the total mass of the complex alcohol and isophorone diisocyanate.

[0037] (3) Mix the epoxy resin, branched epoxy resin A, and branched epoxy resin B to obtain a complex resin. Add a curing agent and benzyl dimethylamine to the complex resin, which is 100g, and stir until uniform to obtain a glue solution. The mass ratio of the epoxy resin E-51, branched epoxy resin A, and branched epoxy resin B is 3:2:1. The amount of benzyl dimethylamine used is 0.3wt% of the total amount of the complex resin. The mass ratio of the complex resin and the curing agent is 3:1.

[0038] The glass fiber cloth is dried at 110°C to remove water, and the glue solution is coated on both sides of the glass fiber cloth, and then cured at 120°C to obtain a semi-cured sheet. Three semi-cured sheets are stacked and hot-pressed to form a composite, with a hot-pressing temperature of 130°C and a pressure of 5MPa. The glue solution coating amount is 250g / m 2 , to obtain a mobile phone shell substrate.

[0039] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure. Coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, and ultraviolet cure to form an inner texture layer. Spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and then imprint an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0040] Example 2:

[0041] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0042] (1) Take the polyol, vacuum dehydrate for 20min, and then mix the polyol with the catalyst, stir until uniform, heat to 65°C, slowly add epoxy chloropropane, and drop for 2h. Keep the temperature for 7h, remove the unreacted epoxy chloropropane, cool to 45°C, dilute with toluene, add solid sodium hydroxide, and keep the temperature for 5.5h. Collect the product by suction filtration, extract the organic phase, wash and dry to obtain the branched epoxy resin. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the polyol.

[0043] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, the reaction obtains branched epoxy resin A; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1014, the reaction obtains branched epoxy resin B; the molar ratio of the hydroxyl group of the polyol, the epoxy chloropropane, and the solid sodium hydroxide is 1:1.2:1.1.

[0044] (2) Take isophorone diisocyanate, compounded alcohol and catalyst, mix under nitrogen environment for 1.5h, the reaction time is 75℃, add ethyl acetate, obtain polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir uniformly, cool to 10℃, add polyurethane prepolymer, react for 2.5h, remove the solvent by distillation, obtain curing agent.

[0045] The compounded alcohol is ethoxylated pentaerythritol with a molecular weight of 355 and ethoxylated pentaerythritol with a molecular weight of 797, compounded with a mass ratio of 1:1; the mass ratio of the compounded alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the total mass of the compounded alcohol and isophorone diisocyanate.

[0046] (3) Take epoxy resin, branched epoxy resin A and branched epoxy resin B, mix to obtain compounded resin, add curing agent and benzyl dimethyl amine to the compounded resin, stir uniformly to obtain glue solution; the mass ratio of the epoxy resin E-51, branched epoxy resin A and branched epoxy resin B is 3:2:1; the amount of benzyl dimethyl amine used is 0.3wt% of the total amount of the compounded resin, and the mass ratio of the compounded resin and curing agent is 3:1.

[0047] Arrange the glass fiber cloth at 110℃ to remove water, coat the glue solution on both sides of the glass fiber cloth, and cure at 120℃ to obtain a semi-cured sheet; stack three semi-cured sheets, hot-press and composite, the hot-press temperature is 135℃, and the pressure is 5MPa; the glue solution coating amount is 250g / m 2 , obtain a mobile phone shell substrate;

[0048] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure; coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, ultraviolet cure to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and imprint to form an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0049] Example 3:

[0050] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0051] (1) Take polyol, vacuum dehydration for 20 min, after dehydration, mix the polyol with catalyst, stir evenly, heat to 65℃, slowly add epichlorohydrin dropwise, dropwise time is 2h, keep warm for 6h, remove unreacted epichlorohydrin, cool to 45℃, dilute with toluene, add solid sodium hydroxide, keep warm for 6h, collect the product by filtration, extract the organic phase, wash and dry, to obtain branched epoxy resin. The catalyst is dibutyltin dilaurate, the amount used is 0.05wt% of the polyol.

[0052] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, the reaction obtains branched epoxy resin A; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1014, the reaction obtains branched epoxy resin B; the molar ratio of the hydroxyl group of the polyol, epichlorohydrin, and solid sodium hydroxide is 1:1.3:1.0.

[0053] (2) Mix isophorone diisocyanate, complex alcohol and catalyst, react for 2h under nitrogen environment, the reaction time is 70℃, add ethyl acetate to obtain polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir evenly, cool to 8℃, add polyurethane prepolymer, react for 2.2h, remove the solvent by distillation to obtain curing agent.

[0054] The complex alcohol is ethoxylated pentaerythritol with a molecular weight of 355 and ethoxylated pentaerythritol with a molecular weight of 797, the mass ratio is 1:1; the mass ratio of the complex alcohol and isophorone diisocyanate is 2:3, the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, the amount used is 0.05wt% of the total mass of the complex alcohol and isophorone diisocyanate.

[0055] (3) Mix epoxy resin, branched epoxy resin A and branched epoxy resin B to obtain complex resin, add curing agent and benzyl dimethyl amine to the complex resin, stir evenly to obtain glue solution; the mass ratio of epoxy resin E-51, branched epoxy resin A and branched epoxy resin B is 3:2:1; the amount of benzyl dimethyl amine is 0.3wt% of the total amount of complex resin, the mass ratio of complex resin and curing agent is 3:1.

[0056] Arrange the glass fiber cloth at 110℃ to remove water, coat glue solution on both sides of the glass fiber cloth, cure at 120℃ to obtain semi-cured sheet; stack three pieces of semi-cured sheet, hot press composite, hot press temperature is 140℃, pressure is 5MPa; the amount of glue solution coating is 250g / m 2 , to obtain a mobile phone shell substrate;

[0057] (4) Take the mobile phone shell substrate, spray primer on one side surface, bake and cure; coat UV glue on the textured surface of the inner texture mold, then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, ultraviolet curing, form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, imprint to form an outer texture layer, cover a protective film, CNC process to form, get the finished product mobile phone shell.

[0058] Example 4:

[0059] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0060] (1) Take polyol, vacuum dehydrate for 20 min, mix the polyol with catalyst after dehydration, stir uniformly, heat to 65℃, slowly add epoxy chloropropane, drop for 2 h, keep warm for 7 h, remove unreacted epoxy chloropropane, cool to 45℃, dilute with toluene, add solid sodium hydroxide, keep warm for 5.5 h, collect the product by suction filtration, extract the organic phase, wash and dry, get branched epoxy resin. The catalyst is dibutyltin dilaurate, the amount is 0.05wt% of the polyol.

[0061] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, branched epoxy resin A is obtained; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1014, branched epoxy resin B is obtained; the molar ratio of hydroxyl group of the polyol, epoxy chloropropane and solid sodium hydroxide is 1:1.2:1.1.

[0062] (2) Mix isophorone diisocyanate, compounded alcohol and catalyst, react for 1.5 h in nitrogen environment, the reaction time is 75℃, add ethyl acetate, get polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate in nitrogen environment, stir uniformly, cool to 10℃, add polyurethane prepolymer, react for 2.5 h, distill the solvent to get curing agent.

[0063] The compounded alcohol is ethoxylated pentaerythritol with a molecular weight of 355 and ethoxylated pentaerythritol with a molecular weight of 797, compounded with a mass ratio of 1:1; the mass ratio of the compounded alcohol and isophorone diisocyanate is 2:3, the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, the amount is 0.05wt% of the total mass of the compounded alcohol and isophorone diisocyanate.

[0064] (3) Take epoxy resin, branched epoxy resin A, branched epoxy resin B, and mix to obtain a compounded resin. Take 100g of the compounded resin, add curing agent and benzyl dimethylamine, stir uniformly, add surface silane coupling agent treated fluorinated graphene and surface silane coupling agent treated graphene oxide, stir uniformly, and obtain a glue solution; the mass ratio of epoxy resin E-51, branched epoxy resin A and branched epoxy resin B is 3:2:1; the amount of benzyl dimethylamine is 0.3wt% of the total amount of the compounded resin, and the mass ratio of the compounded resin and the curing agent is 3:1. The amount of fluorinated graphene is 0.5wt% of the total amount of the compounded resin, and the amount of graphene oxide is 0.8wt% of the total amount of the compounded resin.

[0065] The surface silane coupling agent treatment step of fluorinated graphene and graphene oxide is: take KH-560, methanol and deionized water, mix at a volume ratio of 5:1:1, ultrasonic dispersion for 15min, hydrolysis at 40℃ for 20h, then add fluorinated graphene or graphene oxide, react at 85℃ water bath for 3h, centrifugal washing, freeze drying. The mass ratio of material to KH-560 is 1:5.

[0066] The glass fiber cloth is dried at 110℃ to remove water, the glue solution is coated on both sides of the glass fiber cloth, and the semi-cured sheet is obtained by curing at 120℃. Three pieces of semi-cured sheets are stacked and hot-pressed to form a composite, the hot-pressing temperature is 140℃, the pressure is 5MPa, and the glue solution coating amount is 250g / m 2 , to obtain a mobile phone shell substrate;

[0067] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure; coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, and ultraviolet cure to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and imprint to form an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0068] Comparative Example 1: Comparative Example 1 takes Example 4 as a control group, and the graphene oxide and fluorinated graphene in Comparative Example 1 are not treated with silane coupling agent, and the remaining steps are unchanged.

[0069] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0070] (1) Take polyol, vacuum dehydration for 20 min, after dehydration, mix the polyol with catalyst, stir evenly, heat to 65℃, slowly add epichlorohydrin, drop time is 2h, keep reaction for 7h, remove unreacted epichlorohydrin, cool to 45℃, dilute with toluene, add solid sodium hydroxide, keep reaction for 5.5h, collect product by filtration, extract organic phase, wash and dry, get branched epoxy resin. Catalyst is dibutyltin dilaurate, amount is 0.05wt% of polyol.

[0071] When the polyol is ethoxylated pentaerythritol with molecular weight 797, the reaction gets branched epoxy resin A; when the polyol is ethoxylated trimethylolpropane with molecular weight 1014, the reaction gets branched epoxy resin B; the molar ratio of hydroxyl of the polyol, epichlorohydrin, solid sodium hydroxide is 1:1.2:1.1.

[0072] (2) Mix isophorone diisocyanate, complex alcohol and catalyst, react for 1.5h under nitrogen environment, reaction time is 75℃, add ethyl acetate, get polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir evenly, cool to 10℃, add polyurethane prepolymer, react for 2.5h, remove solvent by distillation, get curing agent.

[0073] The complex alcohol is ethoxylated pentaerythritol with molecular weight 355 and ethoxylated pentaerythritol with molecular weight 797, mass ratio is 1:1; the mass ratio of the complex alcohol, isophorone diisocyanate is 2:3, the mass ratio of the polyurethane prepolymer, trimethylhexanediamine is 1:10. Catalyst is dibutyltin dilaurate, amount is 0.05wt% of the total mass of the complex alcohol and isophorone diisocyanate.

[0074] (3) Mix epoxy resin, branched epoxy resin A, branched epoxy resin B, get complex resin, in 100g of the complex resin, add curing agent and benzyldimethylamine, stir evenly, add fluorinated graphene and graphene oxide, stir evenly, get glue solution; the mass ratio of epoxy resin E-51, branched epoxy resin A, branched epoxy resin B is 3:2:1; the amount of benzyldimethylamine is 0.3wt% of the total amount of the complex resin, the mass ratio of the complex resin and curing agent is 3:1. The amount of fluorinated graphene is 0.5wt% of the total amount of the complex resin, the amount of graphene oxide is 0.8wt% of the total amount of the complex resin.

[0075] Arrange glass fiber cloth at 110℃ to remove water, coat glue solution on both sides of the glass fiber cloth, cure at 120℃, get prepreg; stack three pieces of prepreg, hot press composite, hot press temperature is 140℃, pressure is 5MPa; the amount of glue solution coating is 250g / m 2, to obtain the mobile phone shell substrate;

[0076] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure; coat UV glue on the textured surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, ultraviolet curing, to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and press to form an outer texture layer, cover a protective film, and CNC process to form, to obtain a finished mobile phone shell.

[0077] Comparative Example 2: Comparative Example 2 takes Example 4 as a control group, and no branched epoxy resin B is added in Comparative Example 2, and the remaining steps remain unchanged.

[0078] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0079] (1) Take polyol, vacuum dehydrate for 20 min, mix the polyol with a catalyst after dehydration, stir uniformly, heat to 65℃, slowly drop epoxy chloropropane, drop for 2 h, keep warm for 7 h, remove unreacted epoxy chloropropane, cool to 45℃, dilute with toluene, add solid sodium hydroxide, keep warm for 5.5 h, collect the product by suction filtration, extract the organic phase, wash and dry, to obtain branched epoxy resin. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the polyol.

[0080] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, the branched epoxy resin A is obtained by reaction; the molar ratio of the hydroxyl group of the polyol, epoxy chloropropane, and solid sodium hydroxide is 1:1.2:1.1.

[0081] (2) Mix isophorone diisocyanate, compounded alcohol, and catalyst, react in a nitrogen environment for 1.5 h, the reaction time is 75℃, add ethyl acetate, to obtain polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate in a nitrogen environment, stir uniformly, cool to 10℃, add polyurethane prepolymer, react for 2.5 h, distill the solvent to obtain a curing agent.

[0082] The compounded alcohol is ethoxylated pentaerythritol with a molecular weight of 355 and ethoxylated pentaerythritol with a molecular weight of 797, compounded in a mass ratio of 1:1; the mass ratio of the compounded alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, and the amount used is 0.05wt% of the total mass of the compounded alcohol and isophorone diisocyanate.

[0083] (3) Take epoxy resin, branched epoxy resin A mixed, get compound resin, in compound resin 100 g as a measure, add curing agent and benzyl dimethylamine, stir evenly, add surface silane coupling agent treated fluorinated graphene, surface silane coupling agent treated graphene oxide, stir evenly, get glue liquid;The mass ratio of epoxy resin E-51, branched epoxy resin A is 3:2;The dosage of benzyl dimethylamine is 0.3wt% of the total amount of compound resin, the mass ratio of compound resin and curing agent is 3:1. The dosage of fluorinated graphene is 0.5wt% of the total amount of compound resin, and the dosage of graphene oxide is 0.8wt% of the total amount of compound resin.

[0084] The surface silane coupling agent treatment step of fluorinated graphene and graphene oxide is: take KH-560, methanol and deionized water, mix in the volume ratio of 5:1:1, ultrasonic dispersion for 15 min, hydrolysis at 40℃ for 20h, then add fluorinated graphene or graphene oxide, react for 3h under 85℃ water bath, centrifugal washing, freeze drying. The mass ratio of material to KH-560 is 1:5.

[0085] The glass fiber is dried at 110℃ to remove water, the glue liquid is coated on both sides of the glass fiber cloth, and the semi-cured sheet is obtained by curing at 120℃. Three pieces of semi-cured sheet are stacked and hot pressed to form a composite, the hot pressing temperature is 140℃, the pressure is 5MPa, and the glue liquid coating amount is 250g / m 2 , to obtain a mobile phone shell substrate.

[0086] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure;Coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer on the UV glue surface, and ultraviolet cure to form an inner texture layer;Spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and imprint to form an outer texture layer, cover protective film, and CNC process to form a finished mobile phone shell.

[0087] Comparative example 3: Comparative example 3 takes example 4 as control group, and branched epoxy resin B and branched epoxy resin A are not added in comparative example 3, and the rest of the steps remain unchanged.

[0088] The surface waterproof transfer process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0089] (1) Take isophorone diisocyanate, compound alcohol and catalyst, mix, react under nitrogen environment for 1.5h, reaction time is 75℃, add ethyl acetate, get polyurethane prepolymer;Mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir evenly, cool to 10℃, add polyurethane prepolymer, react for 2.5h, distill the solvent to get curing agent.

[0090] The complex alcohol is ethoxylated pentaerythritol with a molecular weight of 355, ethoxylated pentaerythritol with a molecular weight of 797, and the mass ratio is 1:1; the mass ratio of the complex alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, and the amount is 0.05wt% of the total mass of the complex alcohol and isophorone diisocyanate.

[0091] (2) Take the epoxy resin as a complex resin, and add a curing agent and benzyl dimethylamine to the complex resin, 100g, stir uniformly, add surface silane coupling agent treated fluorinated graphene and surface silane coupling agent treated graphene oxide, stir uniformly, and obtain a glue solution; the amount of benzyl dimethylamine is 0.3wt% of the total amount of the complex resin, and the mass ratio of the complex resin and the curing agent is 3:1. The amount of fluorinated graphene is 0.5wt% of the total amount of the complex resin, and the amount of graphene oxide is 0.8wt% of the total amount of the complex resin.

[0092] The surface silane coupling agent treatment steps of fluorinated graphene and graphene oxide are as follows: mix KH-560, methanol and deionized water in a volume ratio of 5:1:1, ultrasonic dispersion for 15min, hydrolysis at 40℃ for 20h, then add fluorinated graphene or graphene oxide, react at 85℃ water bath for 3h, centrifugal washing, and freeze drying. The mass ratio of the material to KH-560 is 1:5.

[0093] The glass fiber is dried at 110℃ to remove water, the glue solution is coated on both sides of the glass fiber cloth, and the glue solution is cured at 120℃ to obtain a semi-cured sheet; three semi-cured sheets are stacked and hot-pressed to form a composite, the hot-pressing temperature is 140℃, the pressure is 5MPa; the glue solution coating amount is 250g / m 2 , to obtain a mobile phone shell substrate;

[0094] (3) Take the mobile phone shell substrate, spray primer on one side of the surface, and bake and cure; coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, and ultraviolet cure to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and imprint to form an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0095] Comparative Example 4: Comparative Example 4 uses Example 4 as a control group, and adjusts the curing agent preparation steps in Comparative Example 4, and the remaining steps remain unchanged.

[0096] The surface waterproof transfer printing process of the mobile phone shell based on the glass fiber epoxy resin plate material includes the following steps:

[0097] (1) Take polyol, vacuum dehydration for 20 min, after dehydration, mix the polyol with catalyst, stir evenly, heat to 65℃, slowly add epichlorohydrin dropwise, dropwise time is 2h, keep warm for 7h, remove unreacted epichlorohydrin, cool to 45℃, dilute with toluene, add solid sodium hydroxide, keep warm for 5.5h, collect the product by filtration, extract the organic phase, wash and dry, to obtain branched epoxy resin. The catalyst is dibutyltin dilaurate, the amount is 0.05wt% of polyol.

[0098] When the polyol is ethoxylated pentaerythritol with a molecular weight of 797, the reaction obtains branched epoxy resin A; when the polyol is ethoxylated trimethylolpropane with a molecular weight of 1014, the reaction obtains branched epoxy resin B; the molar ratio of the hydroxyl group of the polyol, epichlorohydrin, and solid sodium hydroxide is 1:1.2:1.1.

[0099] (2) Take isophorone diisocyanate, complex alcohol and catalyst, mix, react for 1.5h under nitrogen environment, the reaction time is 75℃, add ethyl acetate to obtain polyurethane prepolymer; mix trimethylhexanediamine and ethyl acetate under nitrogen environment, stir evenly, cool to 10℃, add polyurethane prepolymer, react for 2.5h, remove the solvent by distillation to obtain curing agent.

[0100] The mass ratio of the complex alcohol, isophorone diisocyanate is 2:3, the mass ratio of the polyurethane prepolymer, trimethylhexanediamine is 1:10. The catalyst is dibutyltin dilaurate, the amount is 0.05wt% of the total mass of the complex alcohol and isophorone diisocyanate.

[0101] (3) Take epoxy resin, branched epoxy resin A, branched epoxy resin B, mix to obtain complex resin, in 100g of the complex resin, add curing agent and benzyl dimethyl amine, stir evenly, add surface silane coupling agent treated fluorinated graphene and surface silane coupling agent treated graphene oxide, stir evenly to obtain glue solution; the mass ratio of the epoxy resin E-51, branched epoxy resin A, branched epoxy resin B is 3:2:1; the amount of benzyl dimethyl amine is 0.3wt% of the total amount of the complex resin, the mass ratio of the complex resin and curing agent is 3:1. The amount of fluorinated graphene is 0.5wt% of the total amount of the complex resin, the amount of graphene oxide is 0.8wt% of the total amount of the complex resin.

[0102] The surface silane coupling agent treatment step of fluorinated graphene or graphene oxide is as follows: taking KH-560, methanol and deionized water, mixing them in a volume ratio of 5:1:1, ultrasonic dispersion for 15 min, hydrolysis at 40℃ for 20 h, then adding fluorinated graphene or graphene oxide, reacting at 85℃ in a water bath for 3 h, centrifugal washing, and freeze-drying. The mass ratio of the material to KH-560 is 1:5.

[0103] The glass fiber cloth is dried at 110℃ to remove water, and the glue solution is coated on both sides of the glass fiber cloth, and cured at 120℃ to obtain a semi-cured sheet; three semi-cured sheets are laminated and hot-pressed, the hot-pressing temperature is 140℃, the pressure is 5MPa, and the glue solution coating amount is 250g / m 2 , to obtain a mobile phone shell substrate;

[0104] (4) Take the mobile phone shell substrate, spray primer on one side surface, and bake and cure; coat UV glue on the texture surface of the inner texture mold, and then paste the mobile phone shell substrate sprayed with primer to the UV glue surface, and ultraviolet cure to form an inner texture layer; spray PU pearl paint on the surface of the inner texture layer, bake and cure, then spray topcoat, bake and cure, and imprint to form an outer texture layer, cover a protective film, and CNC process to form a finished mobile phone shell.

[0105] Detection experiment:

[0106] According to the methods disclosed in Examples 1-3 and Comparative Examples 1-4, the performance of the mobile phone shell substrate is detected, and the details are as follows:

[0107] 1. The mobile phone shell substrate is soaked in deionized water for 7 h, the test temperature is 25℃, and the weight before and after the test is recorded to calculate the water absorption rate.

[0108] 2. According to GB / T1447-2005, the tensile strength of the mobile phone shell substrate is detected, the size is 250mm×25mm, and the loading speed is 2mm / min.

[0109]

[0110] Conclusion: The application discloses a surface waterproof transfer printing process of a mobile phone shell based on a glass fiber epoxy resin plate, the process design is reasonable, the glue solution components are properly adjusted, the prepared mobile phone shell has excellent strength and water resistance, and the mechanical properties such as compressive strength are also excellent, and can be widely applied to mobile phone or other electronic product shell processing, and has high practicality.

[0111] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A surface waterproofing transfer process for a mobile phone case based on a glass fiber epoxy resin plate, characterized by: Comprise the following steps: (1) take polyol, vacuum dehydration 20~30min, after dehydration, polyol and catalyst mixed, stirring, heating to 60~65℃, slowly drop the epichlorohydrin, incubation reaction 6~8h, remove the unreacted epichlorohydrin, cooling to 40~45℃, methylbenzene dilution, the addition of solid sodium hydroxide incubation reaction 5~6h, filter collection product, extraction organic phase, washing and drying, branched epoxy resin is obtained; When the polyol is ethoxylated pentaerythritol with molecular weight of 600~800, branched epoxy resin A is obtained; when the polyol is ethoxylated trimethylol propane with molecular weight of 1000~1200, branched epoxy resin B is obtained; (2) take epoxy resin, branched epoxy resin A, branched epoxy resin B mixed, get compound resin, in compound resin, curing agent and benzyl dimethyl amine are added, stirring is uniformly, get glue liquid;Glass fiber is arranged in 100~110 ℃ and is dried, the glue liquid is coated on both sides of glass fiber cloth, 110~120 ℃ is cured, and the semi-cured sheet is obtained;A number of semi-cured sheets are stacked, hot-pressed and compounded to obtain a mobile phone shell substrate; (3) take mobile phone shell substrate, spray primer on one side surface, and bake and cure;UV glue is coated on the texture surface of inner texture mold, and the mobile phone shell substrate sprayed with primer is attached to the UV glue surface, and ultraviolet curing is formed to form an inner texture layer;PU pearl paint is sprayed on the surface of the inner texture layer, and baking and curing are carried out, and then topcoat is sprayed, and baking and curing are carried out to form an outer texture layer, and a protective film is covered, and CNC processing is formed to obtain a finished mobile phone shell; In the above reaction, the catalyst is dibutyltin dilaurate; The epoxy resin is epoxy resin E-44 or epoxy resin E-51.

2. The surface waterproofing process for mobile phone case based on glass fiber epoxy resin sheet material as claimed in claim 1, wherein: In step (1), the molar ratio of the hydroxyl group of the polyol, epichlorohydrin and solid sodium hydroxide is 1:(1.1~1.3):(1~1.1).

3. The surface waterproofing process for mobile phone case based on glass fiber epoxy resin sheet material as claimed in claim 1, wherein: In step (2), the curing agent preparation step is: take isophorone diisocyanate, compound alcohol and catalyst mixed, reaction 1~2h under nitrogen environment, reaction time is 70~75℃, add ethyl acetate, get polyurethane prepolymer; Trimethylhexanediamine and ethyl acetate are mixed under nitrogen environment, stirring is uniformly, cooling to 5~10℃, polyurethane prepolymer is added, reaction 2~2.5h, distillation is removed to obtain curing agent.

4. The surface waterproofing process for mobile phone case based on glass fiber epoxy resin sheet material as claimed in claim 3, wherein: The compound alcohol is ethoxylated pentaerythritol with molecular weight of 300~400 and ethoxylated pentaerythritol with molecular weight of 600~800, and the mass ratio is 1:1;The mass ratio of the compound alcohol and isophorone diisocyanate is 2:3, and the mass ratio of the polyurethane prepolymer and trimethylhexanediamine is 1:(9~10).

5. The surface waterproofing process for mobile phone case based on glass fiber epoxy sheet material as claimed in claim 1, wherein: In step (2), the mass ratio of the epoxy resin, branched epoxy resin A and branched epoxy resin B is 3:2:1;The dosage of benzyl dimethyl amine is 0.3~0.4wt% of the total amount of compound resin, and the mass ratio of the compound resin and curing agent is 3:

1.

6. The surface waterproofing process for mobile phone case based on glass fiber epoxy sheet material as claimed in claim 1 wherein: In step (2), the hot-pressing temperature is 130-140 DEG C, the pressure is 5-10 MPa, and the glue solution coating amount is 150-250 g / m2.

7. The surface waterproofing process for mobile phone case based on glass fiber epoxy sheet material as claimed in claim 1, wherein: In step (2), the glue solution contains fluorinated graphene and graphene oxide, the amount of the fluorinated graphene is 0.5-0.8 wt% of the total amount of the compounded resin, and the amount of the graphene oxide is 0.8-1 wt% of the total amount of the compounded resin. The surfaces of the fluorinated graphene and the graphene oxide are treated by a silane coupling agent, and the specific steps are as follows: mixing KH-560, methanol and deionized water, ultrasonic dispersion for 10-20 min, hydrolysis at 30-40 DEG C for 20-24 h, then adding fluorinated graphene or graphene oxide, reaction at 80-85 DEG C for 3-4 h, centrifugal washing and freeze-drying.

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