Mobile phone rear cover coating liquid as well as preparation method and application thereof

Abstract

The invention relates to the technical field of materials, in particular to mobile phone rear cover coating liquid as well as a preparation method and application thereof. Comprising the following raw materials in parts by weight: 20-40 parts of composite resin, 1-5 parts of a curing agent, 40-60 parts of a diluent, 8-16 parts of a polymerizable monomer, 6-10 parts of a photoinitiator, 1-5 parts of chiral molecules, 1-3 parts of a filler, 1-5 parts of a coupling agent, 0.5-1.5 parts of a leveling agent, 4-8 parts of modified fibers, 4-8 parts of a polyurethane prepolymer and 1-3 parts of tourmaline. The coating liquid has good coating performance, the appearance of a coating is effectively improved, the coating has good toughness, after the coating liquid is coated on the rear cover of the mobile phone, the polymerizable monomer is subjected to a polymerization reaction through illumination, meanwhile, the curing agent, the resin and other components are subjected to a curing reaction, and the coating is gradually formed and cured on the rear cover of the mobile phone.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a coating liquid for a mobile phone rear cover, a preparation method and an application thereof. Background Art

[0002] From the first battlefield mobile phone to today's smart phones, mobile phones are becoming more and more powerful, and the trend of mobile phone innovation is endless. In addition to paying more attention to the performance of mobile phones, consumers are also increasingly demanding the appearance of mobile phones. Nowadays, smart phones are no longer simple tools for making calls and chatting, but more like a close-fitting fashion embellishment to show personal taste. Therefore, whether the appearance of a mobile phone conforms to the trend must become the focus of consumers' consideration when purchasing mobile phones.

[0003] The non-metallic materials in the existing mobile phone case back cover are mainly glass, plastic and ceramic. Among them, plastic materials have the characteristics of low cost and easy molding, making them the most popular materials for mobile phone case back covers. Most of the mobile phone case back cover coatings on the market do not perform well on the mobile phone case back cover, with poor adhesion and poor wear resistance of the outer layer of the mobile phone case back cover, making the mobile phone back cover easily damaged. The coating is not fine enough, the texture is not three-dimensional enough, and it is easy to leave fingerprints, which seriously affects the appearance of the mobile phone. Therefore, there is still room for improvement. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a coating liquid for the back cover of a mobile phone, the coating liquid has good coating performance, effectively improves the coating appearance, and the coating has good toughness. After the coating liquid is applied to the back cover of the mobile phone, the polymerizable monomer is polymerized by light, and at the same time, the curing agent reacts with the resin and other components to cause a curing reaction, so that the coating is gradually formed and cured on the back cover of the mobile phone.

[0005] The invention aims to provide a method for preparing a coating liquid for a mobile phone rear cover. The method has the advantages of simple operation, convenient control, high production efficiency, low production cost and is suitable for large-scale production.

[0006] The purpose of the present invention is to provide an application of a coating liquid for a mobile phone back cover. After the coating liquid is applied to the mobile phone back cover, the polymerizable monomer undergoes a polymerization reaction through light (because it contains a photoinitiator), and at the same time, a curing agent undergoes a curing reaction with components such as a resin, so that a coating is gradually formed and cured on the mobile phone back cover. In this process, the leveling agent plays a role in making the coating surface flat and smooth.

[0007] The purpose of the present invention is achieved through the following technical scheme: a coating liquid for the back cover of a mobile phone, comprising the following raw materials in parts by weight: 20-40 parts of a composite resin, 1-5 parts of a curing agent, 40-60 parts of a diluent, 8-16 parts of a polymerizable monomer, 6-10 parts of a photoinitiator, 1-5 parts of a chiral molecule, 1-3 parts of a filler, 1-5 parts of a coupling agent, 0.5-1.5 parts of a leveling agent, 4-8 parts of modified fibers, 4-8 parts of a polyurethane prepolymer and 1-3 parts of tourmaline; the filler is fumed silica, and the coupling agent is a silane coupling agent.

[0008] The coating liquid of the present invention has good coating performance, effectively improves the appearance of the coating, and the coating has good toughness. Among them, the modified fiber and the polyurethane prepolymer can enhance the toughness of the coating, so that the coating is not easy to crack or peel off when subjected to external impact or bending, and improves the impact resistance of the coating; the isocyanate group (-NCO) in the isocyanate curing agent will react with the active groups such as hydroxyl (-OH) or amino (-NH2) in the composite resin. For example, it reacts with the hydroxyl group in the polyurethane acrylate to form a urea bond or an urethane bond, so that the molecular chains are cross-linked, thereby curing the coating. The reaction formula is roughly: -NCO+-OH→-NH-CO-O-; the photoinitiator will generate free radicals under light conditions. Since the polymerizable monomer has multiple polymerizable groups (such as acryloyl, methacryloyl, etc.), these polymerizable groups will undergo free radical polymerization under the initiation of the free radicals generated by the photoinitiator. Taking acryloyl as an example, the reaction formula for the free radical (R·) generated by the photoinitiator to initiate the polymerization of acryloyl is: R·+CH2=CH-CO-→R-CH2-CH·-CO-, and then the newly generated free radicals will continue to react with other polymerizable monomers, so that the molecular chain continues to grow, forming a three-dimensional network structure, and increasing the strength and stability of the coating; the silane coupling agent can act as a bridge between the filler and the resin matrix. One end of the silane coupling agent can react with the hydroxyl group (-OH) on the surface of the filler, and the other end can react with the active group in the resin molecular chain, thereby enhancing the bonding force between the filler and the resin and improving the comprehensive performance of the coating.

[0009] Preferably, the modified fiber is obtained by the following method: sequentially subjecting glass fiber to plasma treatment and vinyl polyborosiloxane precursor liquid treatment to obtain modified glass fiber; wherein the working conditions of the plasma treatment are: power of 120-150W, time of 1-5min, and working gas of oxygen;

[0010] The vinyl polyborosiloxane precursor liquid treatment comprises the following steps: vinyl-terminated dimethyl polysiloxane and boric acid are mixed in a mass ratio of 0.8-1.2:1.0, and the mixture is kept warm at 60-70°C for 20-40 minutes to obtain a precursor liquid; the pretreated glass fiber and the precursor liquid are mixed in a mass ratio of 1:1.5-2.5, and the mixture is ultrasonically treated for 5-15 minutes, the mixture is heated to 140-180°C, the mixture is kept warm for 1-3 hours, and the mixture is cooled and dried to obtain a modified fiber.

[0011] In the present invention, the glass fiber is subjected to plasma treatment to improve the surface activity of the glass fiber, improve the bonding strength between the glass fiber and the vinyl polyborosiloxane precursor liquid, and form vinyl polyborosiloxane on the surface of the glass fiber by utilizing the reaction of vinyl-terminated dimethyl polysiloxane and boric acid. While improving the mechanical strength of the glass fiber, the surface of the glass fiber is given carbon-carbon double bonds, so that the glass fiber can undergo free radical polymerization with the polyurethane prepolymer under the presence of a photoinitiator, thereby improving the bonding strength between the precursor liquid and the glass fiber, giving the glass fiber a self-repairing surface, and improving the hydrophobicity of the coating, giving it a super-hydrophobic surface.

[0012] Preferably, the tourmaline needs to be pretreated before use, specifically by the following pretreatment method: the tourmaline is dispersed in N,N-dimethylformamide and centrifuged and washed, and then dried after washing to obtain a dispersion liquid, and then isophorone diisocyanate is dropped into the dispersion liquid for reaction, and dried to obtain isophorone diisocyanate pretreated tourmaline; the mass ratio of the amount of the tourmaline, N,N-dimethylformamide and isophorone diisocyanate used is 1:3-7:0.5-1.5.

[0013] In the present invention, the addition of tourmaline to the coating liquid may give the coating certain electrical properties, for example, tourmaline has piezoelectricity and thermoelectricity; it may also make the coating of the back cover of the mobile phone produce some purification or improvement effects, such as the main effects of tourmaline powder in mobile phone coatings include purifying indoor air, releasing negative ions, possibly having an electromagnetic shielding effect, and enhancing the acid resistance and solvent resistance of the mobile phone shell. These characteristics make the application of tourmaline powder in mobile phone coating liquid not only increase the functionality of the mobile phone, but also may help improve the health and user experience of users.

[0014] Preferably, the composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 0.8-1.2:0.7-1.0:1.2.

[0015] The composite resin in the present invention is one of the main components, wherein the composite resin composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer can provide good adhesion and hardness, so that the mobile phone back cover coating can be firmly attached to the mobile phone back cover, and has certain wear resistance to resist scratches in daily use.

[0016] Preferably, the curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from at least one of Bayer N-3200, Bayer N-3300, Bayer N-3600, Bayer N-3800, Asahi Kasei TSE-100, and AE700-100.

[0017] The curing agent (isocyanate curing agent) in the present invention can undergo a cross-linking reaction with the composite resin and other components to further improve the hardness, wear resistance and chemical stability of the coating, so that it can resist erosion by external environmental factors such as moisture, chemicals, etc.

[0018] Preferably, the diluent is one or more of ethyl acetate, methanol, ethanol, isopropanol, cyclohexane, cyclopropanone, cyclohexanone, toluene-cyclohexanone, dioxane, ethylene glycol, glycerol, styrene, ethyl acetate, and ethylene glycol monomethyl ether.

[0019] Preferably, the polymerizable monomer has multiple polymerizable groups, and the polymerizable groups are one or more of: acryloyl, methacryloyl, fluoropropylene, chloropropylene, trifluoromethylpropylene, oxetane, vinyl ether, vinyl ketone, maleimide, phenylmaleimide, vinyl, styrene, diacetyl and epoxy.

[0020] Preferably, the photoinitiator is one or more of TPO, 127 photoinitiator, 184 photoinitiator, and 2959 photoinitiator.

[0021] Preferably, the chiral molecule is one or more of (13BR)-5,6-dihydro-5-(trans-4-propylcyclohexyl)-4H-dinaphtho[2,1-F:1',2'-H][1,5]dioxacyclononatetraene, bis-4-(4'-pentylcyclohexylbenzoate)-(1S)-1-phenyl-1,2-ethylene glycol ester or isopentylbiphenylnitrile.

[0022] The chiral molecules used in the present invention affect the optical properties of the coating, such as changing the refraction, reflection and other properties of light, thereby making the back cover of the mobile phone present a unique visual effect.

[0023] Preferably, the leveling agent is at least one of BYK-103, EFKA-4010, EFKA-4050, EFKA-5065, TEGO-686, TEGO-687, TEGO-655, TEGO-752W, and TEGO-755W.

[0024] The leveling agent (such as BYK-103) used in the present invention can make the coating level better during the drying process, reduce defects on the coating surface, such as orange peel phenomenon, pinholes, etc., thereby obtaining a smooth and flat appearance effect and improving the texture of the back cover of the mobile phone.

[0025] The present invention also provides a method for preparing a coating liquid for a mobile phone rear cover, comprising the following steps:

[0026] S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use;

[0027] S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use;

[0028] S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 40-60° C. and stirring for 20-60 minutes to obtain a coating solution.

[0029] The invention discloses an application of a coating liquid for a mobile phone back cover, comprising the following steps: spraying the coating liquid on the surface of the mobile phone back cover, baking at 100-120° C. for 10-30 minutes, and obtaining a surface treatment coating.

[0030] After the coating liquid is evenly mixed in the present invention and applied to the back cover of the mobile phone, the polymerizable monomer undergoes polymerization reaction by light (because it contains a photoinitiator), and at the same time, the curing agent undergoes a curing reaction with the resin and other components, so that the coating is gradually formed and cured on the back cover of the mobile phone. In this process, the leveling agent plays a role in making the coating surface flat and smooth.

[0031] The beneficial effects of the present invention are as follows: the coating liquid of the present invention has good coating performance, effectively improves the coating appearance, and the coating has good toughness. After the coating liquid is applied to the back cover of a mobile phone, the polymerizable monomer undergoes a polymerization reaction through light irradiation, and at the same time, the curing agent undergoes a curing reaction with the resin and other components, so that the coating is gradually formed and cured on the back cover of the mobile phone.

[0032] The preparation method of the mobile phone rear cover coating liquid of the present invention has the advantages of simple operation, convenient control, high production efficiency and low production cost, and is suitable for large-scale production.

[0033] The present invention discloses an application of a coating liquid for a mobile phone back cover. After the coating liquid is applied to the mobile phone back cover, the polymerizable monomer undergoes a polymerization reaction by light irradiation (because it contains a photoinitiator), and at the same time, a curing agent undergoes a curing reaction with components such as a resin, so that a coating is gradually formed and cured on the mobile phone back cover. In this process, a leveling agent plays a role in making the coating surface flat and smooth. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0035] Example 1

[0036] A coating liquid for a mobile phone back cover comprises the following raw materials in parts by weight: 20 parts of a composite resin, 1 part of a curing agent, 40 parts of a diluent, 8 parts of a polymerizable monomer, 6 parts of a photoinitiator, 1 part of a chiral molecule, 1 part of a filler, 1 part of a coupling agent, 0.5 parts of a leveling agent, 4 parts of modified fibers, 4 parts of a polyurethane prepolymer and 1 part of tourmaline; the filler is fumed silica, and the coupling agent is a silane coupling agent.

[0037] The modified fiber is prepared by the following method: sequentially subjecting the glass fiber to plasma treatment and vinyl polyborosiloxane precursor liquid treatment to obtain the modified glass fiber; wherein the working conditions of the plasma treatment are: power of 120W, time of 5min, and working gas of oxygen;

[0038] The vinyl polyborosiloxane precursor liquid treatment comprises the following steps: vinyl-terminated dimethyl polysiloxane and boric acid are mixed in a mass ratio of 0.8:1.0, and the mixture is kept warm at 60°C for 40 minutes to obtain a precursor liquid; the pretreated glass fiber and the precursor liquid are mixed in a mass ratio of 1:1.5, and the mixture is ultrasonically treated for 15 minutes, the mixture is heated to 140°C and kept warm for 3 hours, and the mixture is cooled and dried to obtain a modified fiber.

[0039] The tourmaline needs to be pretreated before use, and the pretreatment is specifically carried out by the following method: the tourmaline is dispersed in N,N-dimethylformamide and centrifuged and washed, and then dried after washing to obtain a dispersion liquid, and then isophorone diisocyanate is dropped into the dispersion liquid for reaction, and dried to obtain isophorone diisocyanate pretreated tourmaline; the mass ratio of the tourmaline, N,N-dimethylformamide and isophorone diisocyanate is 1:3:0.5.

[0040] The composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 0.8:0.7-:1.2.

[0041] The curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from Bayer N-3200.

[0042] The diluent is ethyl acetate.

[0043] The polymerizable monomer has a plurality of polymerizable groups, and the polymerizable groups are: acryloyl groups.

[0044] The photoinitiator is TPO.

[0045] The chiral molecule is (13BR)-5,6-dihydro-5-(trans-4-propylcyclohexyl)-4H-dinaphtho[2,1-F:1',2'-H][1,5]dioxacyclononatetraene.

[0046] The leveling agent is BYK-103.

[0047] The mobile phone back cover coating liquid is prepared by the following steps:

[0048] S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use;

[0049] S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use;

[0050] S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 40° C. and stirring for 60 minutes to obtain a coating solution.

[0051] The invention discloses an application of a coating liquid for a mobile phone back cover, comprising the following steps: spraying the coating liquid on the surface of the mobile phone back cover, and baking at 100° C. for 30 minutes to obtain a surface treatment coating.

[0052] Example 2

[0053] A coating liquid for a mobile phone back cover comprises the following raw materials in parts by weight: 30 parts of a composite resin, 3 parts of a curing agent, 50 parts of a diluent, 12 parts of a polymerizable monomer, 8 parts of a photoinitiator, 3 parts of a chiral molecule, 2 parts of a filler, 3 parts of a coupling agent, 1.0 part of a leveling agent, 6 parts of modified fibers, 6 parts of a polyurethane prepolymer and 2 parts of tourmaline; the filler is fumed silica, and the coupling agent is a silane coupling agent.

[0054] The modified fiber is prepared by the following method: sequentially subjecting the glass fiber to plasma treatment and vinyl polyborosiloxane precursor liquid treatment to obtain the modified glass fiber; wherein the working conditions of the plasma treatment are: power of 140 W, time of 3 min, and working gas of oxygen;

[0055] The vinyl polyborosiloxane precursor liquid treatment comprises the following steps: vinyl-terminated dimethyl polysiloxane and boric acid are mixed in a mass ratio of 1.0:1.0, and the mixture is kept warm at 65°C for 30 minutes to obtain a precursor liquid; the pretreated glass fiber and the precursor liquid are mixed in a mass ratio of 1:2.0, and the mixture is ultrasonically treated for 10 minutes, the mixture is heated to 160°C and kept warm for 2 hours, and the mixture is cooled and dried to obtain a modified fiber.

[0056] The tourmaline needs to be pretreated before use, and the pretreatment is specifically carried out by the following method: the tourmaline is dispersed in N,N-dimethylformamide and centrifuged and washed, and then dried after washing to obtain a dispersion liquid, and then isophorone diisocyanate is dropped into the dispersion liquid for reaction, and dried to obtain isophorone diisocyanate pretreated tourmaline; the mass ratio of the tourmaline, N,N-dimethylformamide and isophorone diisocyanate is 1:5:1.0.

[0057] The composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 1.0:0.8:1.2.

[0058] The curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from Bayer N-3300.

[0059] The diluent is composed of ethyl acetate, cyclopropanone and ethylene glycol monomethyl ether in a mass ratio of 1:0.7:0.6.

[0060] The polymerizable monomer has a plurality of polymerizable groups, and the polymerizable groups are composed of an acryloyl group and a phenylmaleimide group in a mass ratio of 1:1.

[0061] The photoinitiator is 127 photoinitiator.

[0062] The chiral molecule is composed of (13BR)-5,6-dihydro-5-(trans-4-propylcyclohexyl)-4H-dinaphtho[2,1-F:1',2'-H][1,5]dioxacyclononatetraene and bis-4-(4'-pentylcyclohexylbenzoate)-(1S)-1-phenyl-1,2-ethylene glycol ester in a mass ratio of 1:1.

[0063] The leveling agent is TEGO-687.

[0064] The mobile phone back cover coating liquid is prepared by the following steps:

[0065] S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use;

[0066] S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use;

[0067] S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 50° C. and stirring for 40 minutes to obtain a coating solution.

[0068] The invention discloses an application of a coating liquid for a mobile phone back cover, comprising the following steps: spraying the coating liquid on the surface of the mobile phone back cover, and baking at 110° C. for 20 minutes to obtain a surface treatment coating.

[0069] Example 3

[0070] A coating liquid for a mobile phone back cover comprises the following raw materials in parts by weight: 40 parts of a composite resin, 5 parts of a curing agent, 60 parts of a diluent, 16 parts of a polymerizable monomer, 10 parts of a photoinitiator, 5 parts of a chiral molecule, 3 parts of a filler, 5 parts of a coupling agent, 1.5 parts of a leveling agent, 8 parts of modified fibers, 8 parts of a polyurethane prepolymer and 3 parts of tourmaline; the filler is fumed silica, and the coupling agent is a silane coupling agent.

[0071] The modified fiber is prepared by the following method: sequentially subjecting the glass fiber to plasma treatment and vinyl polyborosiloxane precursor liquid treatment to obtain the modified glass fiber; wherein the working conditions of the plasma treatment are: power of 150 W, time of 1 min, and working gas of oxygen;

[0072] The vinyl polyborosiloxane precursor liquid treatment comprises the following steps: vinyl-terminated dimethyl polysiloxane and boric acid are mixed in a mass ratio of 1.2:1.0, and the mixture is kept warm at 70°C for 20 minutes to obtain a precursor liquid; the pretreated glass fiber and the precursor liquid are mixed in a mass ratio of 1:1.5-2.5, and the mixture is ultrasonically treated for 5 minutes, the mixture is heated to 180°C and kept warm for 1 hour, and the mixture is cooled and dried to obtain a modified fiber.

[0073] The tourmaline needs to be pretreated before use, and the pretreatment is specifically carried out by the following method: the tourmaline is dispersed in N,N-dimethylformamide and centrifuged and washed, and then dried after washing to obtain a dispersion liquid, and then isophorone diisocyanate is dropped into the dispersion liquid for reaction, and dried to obtain isophorone diisocyanate pretreated tourmaline; the mass ratio of the amount of the tourmaline, N,N-dimethylformamide and isophorone diisocyanate used is 1:7:1.5.

[0074] The composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 1.2:1.0:1.2.

[0075] The curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from Asahi Kasei TSE-100.

[0076] The diluent is cyclopropanone.

[0077] The polymerizable monomer has a plurality of polymerizable groups, and the polymerizable group is a trifluoromethylpropylene group.

[0078] The photoinitiator is 2959 photoinitiator.

[0079] The chiral molecule is di-4-(4'-pentylcyclohexylbenzoate)-(1S)-1-phenyl-1,2-ethylene glycol ester.

[0080] The leveling agent is EFKA-5065.

[0081] The mobile phone back cover coating liquid is prepared by the following steps:

[0082] S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use;

[0083] S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use;

[0084] S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 60° C. and stirring for 20 minutes to obtain a coating solution.

[0085] The invention discloses an application of a coating liquid for a mobile phone back cover, comprising the following steps: spraying the coating liquid on the surface of the mobile phone back cover, and baking at 120° C. for 10 minutes to obtain a surface treatment coating.

[0086] Example 4

[0087] A coating liquid for a mobile phone back cover comprises the following raw materials in parts by weight: 30 parts of a composite resin, 3 parts of a curing agent, 50 parts of a diluent, 12 parts of a polymerizable monomer, 8 parts of a photoinitiator, 3 parts of a chiral molecule, 2 parts of a filler, 3 parts of a coupling agent, 1.0 part of a leveling agent, 6 parts of modified fibers, 6 parts of a polyurethane prepolymer and 2 parts of tourmaline; the filler is fumed silica, and the coupling agent is a silane coupling agent.

[0088] The modified fiber is prepared by the following method: sequentially subjecting the glass fiber to plasma treatment and vinyl polyborosiloxane precursor liquid treatment to obtain the modified glass fiber; wherein the working conditions of the plasma treatment are: power of 140 W, time of 3 min, and working gas of oxygen;

[0089] The vinyl polyborosiloxane precursor liquid treatment comprises the following steps: vinyl-terminated dimethyl polysiloxane and boric acid are mixed in a mass ratio of 1.0:1.0, and the mixture is kept warm at 65°C for 30 minutes to obtain a precursor liquid; the pretreated glass fiber and the precursor liquid are mixed in a mass ratio of 1:2.0, and the mixture is ultrasonically treated for 10 minutes, the mixture is heated to 160°C and kept warm for 2 hours, and the mixture is cooled and dried to obtain a modified fiber.

[0090] The tourmaline needs to be pretreated before use, and the pretreatment is specifically carried out by the following method: the tourmaline is dispersed in N,N-dimethylformamide and centrifuged and washed, and then dried after washing to obtain a dispersion liquid, and then isophorone diisocyanate is dropped into the dispersion liquid for reaction, and dried to obtain isophorone diisocyanate pretreated tourmaline; the mass ratio of the tourmaline, N,N-dimethylformamide and isophorone diisocyanate is 1:5:1.0.

[0091] The composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 1.2:1.0:1.2.

[0092] The curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from Asahi Kasei TSE-100.

[0093] The diluent is cyclopropanone.

[0094] The polymerizable monomer has a plurality of polymerizable groups, and the polymerizable group is a trifluoromethylpropylene group.

[0095] The photoinitiator is 2959 photoinitiator.

[0096] The chiral molecule is di-4-(4'-pentylcyclohexylbenzoate)-(1S)-1-phenyl-1,2-ethylene glycol ester.

[0097] The leveling agent is EFKA-5065.

[0098] The mobile phone back cover coating liquid is prepared by the following steps:

[0099] S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use;

[0100] S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use;

[0101] S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 60° C. and stirring for 20 minutes to obtain a coating solution.

[0102] The invention discloses an application of a coating liquid for a mobile phone back cover, comprising the following steps: spraying the coating liquid on the surface of the mobile phone back cover, and baking at 120° C. for 10 minutes to obtain a surface treatment coating.

[0103] Comparative Example 1

[0104] The difference between this comparative example and the above-mentioned Example 2 is that no modified fiber and polyurethane prepolymer are added to the raw materials of the coating liquid of this comparative example. The rest of the contents of this comparative example are the same as those of Example 2 and will not be repeated here.

[0105] Comparative Example 2

[0106] The difference between this comparative example and the above-mentioned Example 2 is that no composite resin and photoinitiator are added to the raw materials of the coating liquid of this comparative example. The rest of the contents of this comparative example are the same as those of Example 2, and will not be repeated here.

[0107] The coating liquids prepared in Example 2 and Comparative Examples 1-2 were subjected to performance tests after film formation, and the results are shown in Table 1:

[0108] Impact strength: refer to GB / T1843-2008 test, sample size is 85mm×15mm, impact energy is 5.5J; Water contact angle: use 2μL deionized water droplet for testing, and take the average value;

[0109] According to GB / T 9286-1998 "Scratching test for paint and varnish films", the 100-grid adhesion of each embodiment and comparative example was tested;

[0110] Anti-explosion performance test: Use a 32g ball to freely fall from a distance of 100cm to the outer surface of the battery back cover until it breaks.

[0111] Table 1

[0112] project <![CDATA[Impact strength (kj / m 2 )]]> Water contact angle (°) Adhesion Anti-burst performance Example 2 297 157 Baige 5B The fragments do not fall apart Comparative Example 1 241 139 100 Grid 2B The fragments are scattered Comparative Example 2 236 140 Baige 3B The fragments are scattered

[0113] It can be seen from Example 2 that the coating liquid prepared by the present invention has the advantages of good adhesion, impact resistance and film-forming performance, as well as excellent hydrophobicity after film formation.

[0114] From the comparison between Example 2 and Comparative Examples 1-2, it can be seen that under the same conditions, the coating liquid prepared by adding water-modified fiber, polyurethane prepolymer, composite resin and photoinitiator to the formula has good adhesion, impact resistance and film-forming properties after film formation, as well as excellent hydrophobicity and other advantages, and has broad market prospects and application value.

[0115] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A coating liquid for a mobile phone back cover, characterized in that: The invention comprises the following raw materials in parts by weight: 20-40 parts of composite resin, 1-5 parts of curing agent, 40-60 parts of diluent, 8-16 parts of polymerizable monomer, 6-10 parts of photoinitiator, 1-5 parts of chiral molecule, 1-3 parts of filler, 1-5 parts of coupling agent, 0.5-1.5 parts of leveling agent, 4-8 parts of modified fiber, 4-8 parts of polyurethane prepolymer and 1-3 parts of tourmaline.

2. The mobile phone back cover coating liquid according to claim 1, characterized in that: The composite resin is composed of vinyl resin, polyurethane acrylate and styrene / acrylic acid (ester) copolymer in a mass ratio of 0.8-1.2:0.7-1.0:1.

2.

3. The mobile phone back cover coating liquid according to claim 1, characterized in that: The curing agent is an isocyanate curing agent; the isocyanate curing agent is selected from at least one of Bayer N-3200, Bayer N-3300, Bayer N-3600, Bayer N-3800, Asahi Kasei TSE-100, and AE700-100.

4. The mobile phone back cover coating liquid according to claim 1, characterized in that: The diluent is one or more of ethyl acetate, methanol, ethanol, isopropanol, cyclohexane, cyclopropanone, cyclohexanone, toluene-cyclohexanone, dioxane, ethylene glycol, glycerol, styrene, ethyl acetate, and ethylene glycol monomethyl ether.

5. The coating liquid for mobile phone rear cover according to claim 1, characterized in that: The polymerizable monomer has multiple polymerizable groups, and the polymerizable groups are one or more of an acryloyl group, a methacryloyl group, a fluoropropylene group, a chloropropylene group, a trifluoromethylpropylene group, an oxetane group, a vinyl ether group, a vinyl ketone group, a maleimide group, a phenylmaleimide group, a vinyl group, a styrene group, a diacetyl group and an epoxy group.

6. The coating liquid for mobile phone rear cover according to claim 1, characterized in that: The photoinitiator is one or more of TPO, 127 photoinitiator, 184 photoinitiator, and 2959 photoinitiator.

7. The mobile phone back cover coating liquid according to claim 1, characterized in that: The chiral molecule is one or more of (13BR)-5,6-dihydro-5-(trans-4-propylcyclohexyl)-4H-dinaphtho[2,1-F:1',2'-H][1,5]dioxacyclononatetraene, bis-4-(4'-pentylcyclohexylbenzoate)-(1S)-1-phenyl-1,2-ethylene glycol ester or isopentylbiphenylnitrile.

8. The mobile phone back cover coating liquid according to claim 1, characterized in that: The leveling agent is at least one of BYK-103, EFKA-4010, EFKA-4050, EFKA-5065, TEGO-686, TEGO-687, TEGO-655, TEGO-752W, and TEGO-755W.

9. A method for preparing a mobile phone rear cover coating liquid according to any one of claims 1 to 8, characterized in that: The steps include: S1. According to parts by weight, the composite resin, polymerizable monomer, photoinitiator, chiral molecule, filler, coupling agent, tourmaline, modified fiber material and diluent are mixed uniformly to obtain a premixed solution for standby use; S2. According to parts by weight, the polyurethane prepolymer and the leveling agent are uniformly mixed to obtain a mixed system for standby use; S3, adding the curing agent and the mixed system obtained in step S2 to the premixed solution obtained in step S1, heating to 40-60° C. and stirring for 20-60 minutes to obtain a coating solution.

10. An application of a coating liquid for a mobile phone back cover, characterized in that: The method comprises the following steps: spraying the mobile phone back cover coating liquid according to any one of claims 1 to 8 onto the surface of the mobile phone back cover, and baking at 100 to 120° C. for 10 to 30 minutes to obtain a surface treatment coating.