Heat dissipation type glass fiber plate for rear cover of mobile phone and preparation process of heat dissipation type glass fiber plate

Abstract

The invention discloses a heat dissipation type glass fiber plate for a rear cover of a mobile phone and a preparation process of the heat dissipation type glass fiber plate, and relates to the technical field of glass fiber plate materials. Glass fiber cloth is subjected to glue solution coating treatment, so that the strength and the heat conductivity coefficient of the glass fiber cloth are improved. The glass fiber cloth is firstly coated with a phytic acid chitosan composite solution, so that the corrosion resistance and flame retardance of the glass fiber cloth are improved. Then, a cobaltous sulfate aqueous solution is coated, cobalt ions in the cobaltous sulfate aqueous solution can form coordination with the phytic acid chitosan composite solution and can form coordination with hydroxyl and amino in the glue solution, and the binding force between the glass fibers and the glue solution is improved.

Description

Technical Field

[0001] This invention relates to the field of fiberglass board material technology, specifically a heat-dissipating fiberglass board for mobile phone back covers and its preparation process. Background Technology

[0002] With the widespread adoption of 5G communication and high refresh rate screens, the overall power consumption and local heat flux density of smartphones are rapidly increasing. Existing phone back covers are unable to dissipate heat effectively, leading to issues such as frequency throttling, shortened battery life, and overheating screens. Therefore, developing back cover materials that combine high strength and high thermal conductivity is crucial. Traditional phone back cover materials mainly include aluminum alloys, glass, and fiberglass. While aluminum alloys have good thermal conductivity, they shield signals and have high processing costs; glass is fragile and has low yield rates in hot bending; thermosetting composite materials, such as fiberglass, have low dielectric constants, but ordinary fiberglass has low thermal conductivity, which cannot meet the heat dissipation requirements of 5G terminals.

[0003] In summary, in order to solve the above problems and improve the heat dissipation performance of fiberglass sheets, this application provides a heat-dissipating fiberglass sheet for mobile phone back covers and its manufacturing process. Summary of the Invention

[0004] The purpose of this invention is to provide a heat-dissipating fiberglass plate for mobile phone back covers and its manufacturing process, so as to solve the problems mentioned in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A manufacturing process for a heat-dissipating fiberglass plate for a mobile phone back cover includes the following steps: Step 1: Take fiberglass cloth, clean it, coat both sides with phytic acid-chitosan composite solution, and dry it to obtain fiberglass cloth A; coat both sides with cobalt sulfate aqueous solution, and dry it to obtain fiberglass cloth B; coat both sides with adhesive, let it stand for 5-10 minutes, introduce a magnetic field with the magnetic field direction and the horizontal of fiberglass cloth B, and the magnetic field strength is 220mT, and cure it to obtain a prepreg; stack N prepregs, hot press them to obtain a fiberglass board; Step 2: Take a fiberglass board, perform screen printing, and then transfer the texture layer onto the surface; Step 3: A film is deposited on the surface of the textured layer by physical vapor deposition, and finally a protective varnish is applied and the layer is cut to obtain a heat-dissipating fiberglass board for the back cover of a mobile phone.

[0006] More preferably, the adhesive is composed of the following substances in parts by weight: 20-24 parts of cobalt-loaded boron nitride, 5-7 parts of cobalt sulfate, 25-30 parts of acetone, 25-30 parts of toluene, 65-70 parts of phenolic resin, 35-40 parts of flame-retardant epoxy resin, 1-2 parts of curing accelerator, and 26-28 parts of curing agent.

[0007] A more optimized method for preparing the flame-retardant epoxy resin is as follows: propylene glycol methyl ether and butanone are taken and stirred evenly to obtain a mixed solvent; bisphenol A type epoxy resin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are taken, heated to 120-130℃, stirred for 2-3 hours, tetramethylammonium chloride is added, the temperature is raised to 150-160℃, and the reaction is stirred for 4-6 hours; isocyanate is added, the temperature is raised to 170-172℃, and the reaction is stirred for 4-5 hours; the mixed solvent is added, and the mixture is stirred evenly to obtain the flame-retardant epoxy resin.

[0008] A more optimized method for preparing cobalt-loaded boron nitride is as follows: take cobalt dichloride, cobalt oxide, and deionized water, stir evenly to obtain a mixed solution; take sodium poly(p-styrene sulfonate) modified boron nitride and deionized water, stir for 3-4 hours, add the mixed solution, stir for 1-2 hours, add 1,6-hexanediamine, stir for 10-20 minutes, let stand for 22-26 hours, wash and dry to obtain cobalt-loaded boron nitride.

[0009] A more optimized method for preparing the sodium poly(p-styrene sulfonate) modified boron nitride includes the following steps: S1: Take hexagonal boron nitride and sodium hydroxide, mix them evenly, react them at 180-185℃ for 7-8 hours, cool, wash and dry to obtain pretreated boron nitride; S2: Pretreated boron nitride and deionized water are ultrasonically dispersed for 6-7 hours, stirred for 2-3 hours, sodium poly(p-styrene sulfonate) is added, the temperature is raised to 50-55℃, stirred for 2-4 hours, acetic acid is added, the pH value is adjusted to 3, and the mixture is allowed to stand for 8-10 hours. After centrifugation, washing, and drying, sodium poly(p-styrene sulfonate) modified boron nitride is obtained.

[0010] In a more optimized manner, the preparation method of the phytic acid-chitosan composite solution is as follows: take chitosan and deionized water, stir evenly, add phytic acid and acetic acid, stir for 2-3 hours to obtain the phytic acid-chitosan composite solution.

[0011] Ideally, the concentration of the cobalt sulfate aqueous solution is 1.0wt%-1.5wt%.

[0012] In a more optimized manner, the preparation method of the adhesive is as follows: cobalt-loaded boron nitride, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. This application improves the strength and thermal conductivity of fiberglass cloth by applying an adhesive coating. First, the fiberglass cloth is coated with a phytic acid-chitosan composite solution to enhance its corrosion resistance and flame retardancy. Then, a cobalt sulfate aqueous solution is applied, where the cobalt ions can coordinate with the phytic acid-chitosan composite solution and with the hydroxyl and amino groups in the adhesive, thereby increasing the bonding force between the fiberglass and the adhesive.

[0014] 2. This application improves the heat dissipation of fiberglass boards by adding boron nitride to the adhesive. Boron nitride has good thermal conductivity, which increases the thermal conductivity coefficient. However, boron nitride is prone to agglomeration, leading to a decrease in the mechanical properties of the fiberglass board. Loading cobalt onto boron nitride promotes the formation of thermally conductive channels, improving the heat dissipation of the fiberglass board. Simultaneously, cobalt is magnetic, and its loading allows the boron nitride to be evenly dispersed under the influence of a magnetic field, further improving the mechanical properties of the fiberglass board.

[0015] 3. This application also adds flame-retardant epoxy resin to the adhesive, which further enhances the flame retardancy of the glass plate. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The sources and types of the substances involved in this invention are not particularly limited. Exemplary examples include: hexagonal boron nitride: 5-10 μm, which can be purchased from Shanghai McLean Co., Ltd.; bisphenol A type epoxy resin: type: 31185, which can be purchased from Merck; phenolic resin: type: P195710, which can be purchased from Aladdin; and fiberglass cloth: type: 1080, thickness 0.05 mm, which can be purchased from Changzhou Xingao Insulation Materials Co., Ltd.

[0018] Example 1: A manufacturing process for a heat-dissipating fiberglass plate for a mobile phone back cover, comprising the following steps: Step 1: Preparation of cobalt-loaded boron nitride: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 182℃ for 7.5h, cool, wash and dry to obtain pretreated boron nitride; 4g of pretreated boron nitride and 200mL of deionized water were ultrasonically dispersed for 6.5h, stirred for 2.5h, 1g of sodium poly(p-styrene sulfonate) was added, the temperature was raised to 52℃, stirred for 3h, acetic acid was added, the pH value was adjusted to 3, and the mixture was allowed to stand for 9h. After centrifugation, washing and drying, sodium poly(p-styrene sulfonate) modified boron nitride was obtained. Take 6g of cobalt dichloride, 2g of cobalt oxide, and 100mL of deionized water, stir well to obtain a mixed solution; take 4g of sodium poly(p-styrene sulfonate) modified boron nitride and 200mL of deionized water, stir for 3.5h, add the mixed solution, stir for 1.5h, add 15g of 1,6-hexanediamine, stir for 15min, let stand for 24h, wash and dry to obtain cobalt-loaded boron nitride; Step 2: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 125℃, stir for 2.5h, add 0.8g of tetramethylammonium chloride, heat to 155℃, stir for 5h, add 10g of isocyanate, heat to 171℃, stir for 4.5h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 3: Preparation of the adhesive solution: Boron nitride loaded with cobalt, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 22 parts boron nitride loaded with cobalt, 6 parts cobalt sulfate, 28 parts acetone, 28 parts toluene, 67 parts phenolic resin, 37 parts flame retardant epoxy resin, 1.5 parts curing accelerator dimethylimidazole, and 27 parts curing agent 4,4-diaminodiphenol. Step 4: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 2.5h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2 After drying, glass fiber cloth A is obtained; a 1 wt% cobalt sulfate aqueous solution is coated on both sides of glass fiber cloth A, with a coating amount of 20 g / m. 2 After drying, fiberglass cloth B is obtained; a coating solution is applied to both sides of fiberglass cloth B, with a coating amount of 190 g / m². 2 After standing for 7 minutes, a magnetic field is introduced, with the magnetic field direction and the glass fiber cloth B horizontally set, and the magnetic field strength is 220mT. Curing is performed to obtain a semi-cured sheet. Six semi-cured sheets are stacked and hot-pressed to obtain a glass fiber board. A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0019] Example 2: A manufacturing process for a heat-dissipating fiberglass plate for a mobile phone back cover, comprising the following steps: Step 1: Preparation of cobalt-loaded boron nitride: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 180℃ for 7h, cool, wash and dry to obtain pretreated boron nitride; 4g of pretreated boron nitride and 200mL of deionized water were ultrasonically dispersed for 6h, stirred for 2h, 1g of sodium poly(p-styrene sulfonate) was added, the temperature was raised to 50℃ and stirred for 2h, acetic acid was added, the pH value was adjusted to 3, and the mixture was allowed to stand for 8h. After centrifugation, washing and drying, sodium poly(p-styrene sulfonate) modified boron nitride was obtained. Take 6g of cobalt dichloride, 2g of cobalt oxide, and 100mL of deionized water, stir well to obtain a mixed solution; take 4g of sodium poly(p-styrene sulfonate) modified boron nitride and 200mL of deionized water, stir for 3h, add the mixed solution, stir for 1h, add 15g of 1,6-hexanediamine, stir for 10min, let stand for 22h, wash and dry to obtain cobalt-loaded boron nitride. Step 2: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 120℃, stir for 2h, add 0.8g of tetramethylammonium chloride, heat to 150℃, stir for 4h, add 10g of isocyanate, heat to 170℃, stir for 4h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 3: Preparation of the adhesive solution: Boron nitride loaded with cobalt, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 20 parts boron nitride loaded with cobalt, 5 parts cobalt sulfate, 25 parts acetone, 25 parts toluene, 65 parts phenolic resin, 35 parts flame retardant epoxy resin, 1 part curing accelerator dimethylimidazole, and 26 parts curing agent 4,4-diaminodiphenol. Step 4: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 2h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2After drying, glass fiber cloth A is obtained; a 1 wt% cobalt sulfate aqueous solution is coated on both sides of glass fiber cloth A, with a coating amount of 20 g / m. 2 After drying, fiberglass cloth B is obtained; a coating solution is applied to both sides of fiberglass cloth B, with a coating amount of 190 g / m². 2 After standing for 5 minutes, a magnetic field is introduced, with the direction of the magnetic field and the horizontal position of the glass fiber cloth B. The magnetic field strength is 220mT. After curing, a semi-cured sheet is obtained. Six semi-cured sheets are stacked and hot-pressed to obtain a glass fiber board. A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0020] Example 3: A manufacturing process for a heat-dissipating fiberglass plate for a mobile phone back cover, comprising the following steps: Step 1: Preparation of cobalt-loaded boron nitride: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 185℃ for 8h, cool, wash and dry to obtain pretreated boron nitride; 4g of pretreated boron nitride and 200mL of deionized water were ultrasonically dispersed for 7h, stirred for 3h, 1g of sodium poly(p-styrene sulfonate) was added, the temperature was raised to 55℃, stirred for 4h, acetic acid was added, the pH value was adjusted to 3, and the mixture was allowed to stand for 10h. After centrifugation, washing and drying, sodium poly(p-styrene sulfonate) modified boron nitride was obtained. Take 6g of cobalt dichloride, 2g of cobalt oxide, and 100mL of deionized water, stir well to obtain a mixed solution; take 4g of sodium poly(p-styrene sulfonate) modified boron nitride and 200mL of deionized water, stir for 4h, add the mixed solution, stir for 2h, add 15g of 1,6-hexanediamine, stir for 20min, let stand for 26h, wash and dry to obtain cobalt-loaded boron nitride. Step 2: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 130℃, stir for 3h, add 0.8g of tetramethylammonium chloride, heat to 160℃, stir for 6h, add 10g of isocyanate, heat to 172℃, stir for 5h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 3: Preparation of the adhesive solution: Boron nitride loaded with cobalt, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 24 parts boron nitride loaded with cobalt, 7 parts cobalt sulfate, 30 parts acetone, 30 parts toluene, 70 parts phenolic resin, 40 parts flame retardant epoxy resin, 2 parts curing accelerator dimethylimidazole, and 28 parts curing agent 4,4-diaminodiphenol. Step 4: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 3h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2 After drying, glass fiber cloth A is obtained; a 1 wt% cobalt sulfate aqueous solution is coated on both sides of glass fiber cloth A, with a coating amount of 20 g / m. 2 After drying, fiberglass cloth B is obtained; a coating solution is applied to both sides of fiberglass cloth B, with a coating amount of 190 g / m². 2 After standing for 10 minutes, a magnetic field is introduced, with the magnetic field direction and the glass fiber cloth B horizontally set, and the magnetic field strength is 220mT. The mixture is then cured to obtain a semi-cured sheet. Six semi-cured sheets are stacked and hot-pressed to obtain a glass fiber board. A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0021] Comparative Example 1: No coating with cobalt sulfate aqueous solution, otherwise the same as Example 1: Step 1: Preparation of cobalt-loaded boron nitride: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 182℃ for 7.5h, cool, wash and dry to obtain pretreated boron nitride; 4g of pretreated boron nitride and 200mL of deionized water were ultrasonically dispersed for 6.5h, stirred for 2.5h, 1g of sodium poly(p-styrene sulfonate) was added, the temperature was raised to 52℃, stirred for 3h, acetic acid was added, the pH value was adjusted to 3, and the mixture was allowed to stand for 9h. After centrifugation, washing and drying, sodium poly(p-styrene sulfonate) modified boron nitride was obtained. Take 6g of cobalt dichloride, 2g of cobalt oxide, and 100mL of deionized water, stir well to obtain a mixed solution; take 4g of sodium poly(p-styrene sulfonate) modified boron nitride and 200mL of deionized water, stir for 3.5h, add the mixed solution, stir for 1.5h, add 15g of 1,6-hexanediamine, stir for 15min, let stand for 24h, wash and dry to obtain cobalt-loaded boron nitride; Step 2: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 125℃, stir for 2.5h, add 0.8g of tetramethylammonium chloride, heat to 155℃, stir for 5h, add 10g of isocyanate, heat to 171℃, stir for 4.5h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 3: Preparation of the adhesive solution: Boron nitride loaded with cobalt, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 22 parts boron nitride loaded with cobalt, 6 parts cobalt sulfate, 28 parts acetone, 28 parts toluene, 67 parts phenolic resin, 37 parts flame retardant epoxy resin, 1.5 parts curing accelerator dimethylimidazole, and 27 parts curing agent 4,4-diaminodiphenol. Step 4: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 2.5h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2 After drying, glass fiber cloth A is obtained; adhesive is coated on both sides of glass fiber cloth A, with a coating amount of 190 g / m. 2 After standing for 7 minutes, a magnetic field is introduced, with the magnetic field direction and the glass fiber cloth B horizontally set, and the magnetic field strength is 220mT. Curing is performed to obtain a semi-cured sheet. Six semi-cured sheets are stacked and hot-pressed to obtain a glass fiber board. A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0022] Comparative Example 2: Cobalt was not loaded onto boron nitride; otherwise, it was the same as in Example 1. Step 1: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 125℃, stir for 2.5h, add 0.8g of tetramethylammonium chloride, heat to 155℃, stir for 5h, add 10g of isocyanate, heat to 171℃, stir for 4.5h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 2: Preparation of the adhesive solution: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 182℃ for 7.5h, cool, wash and dry to obtain pretreated boron nitride; Pretreated boron nitride, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 22 parts pretreated boron nitride, 6 parts cobalt sulfate, 28 parts acetone, 28 parts toluene, 67 parts phenolic resin, 37 parts flame-retardant epoxy resin, 1.5 parts curing accelerator dimethylimidazole, and 27 parts curing agent 4,4-diaminodiphenol. Step 3: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 2.5h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2 After drying, glass fiber cloth A is obtained; a 1 wt% cobalt sulfate aqueous solution is coated on both sides of glass fiber cloth A, with a coating amount of 20 g / m. 2 After drying, fiberglass cloth B is obtained; a coating solution is applied to both sides of fiberglass cloth B, with a coating amount of 190 g / m². 2 After standing for 7 minutes, a magnetic field is introduced, with the magnetic field direction and the glass fiber cloth B horizontally set, and the magnetic field strength is 220mT. Curing is performed to obtain a semi-cured sheet. Six semi-cured sheets are stacked and hot-pressed to obtain a glass fiber board. A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0023] Comparative Example 3: No magnetic field was added; all other aspects were the same as in Example 1. Step 1: Preparation of cobalt-loaded boron nitride: Take 5g of hexagonal boron nitride and 5g of sodium hydroxide, mix them evenly, react at 182℃ for 7.5h, cool, wash and dry to obtain pretreated boron nitride; 4g of pretreated boron nitride and 200mL of deionized water were ultrasonically dispersed for 6.5h, stirred for 2.5h, 1g of sodium poly(p-styrene sulfonate) was added, the temperature was raised to 52℃, stirred for 3h, acetic acid was added, the pH value was adjusted to 3, and the mixture was allowed to stand for 9h. After centrifugation, washing and drying, sodium poly(p-styrene sulfonate) modified boron nitride was obtained. Take 6g of cobalt dichloride, 2g of cobalt oxide, and 100mL of deionized water, stir well to obtain a mixed solution; take 4g of sodium poly(p-styrene sulfonate) modified boron nitride and 200mL of deionized water, stir for 3.5h, add the mixed solution, stir for 1.5h, add 15g of 1,6-hexanediamine, stir for 15min, let stand for 24h, wash and dry to obtain cobalt-loaded boron nitride; Step 2: Preparation of flame-retardant epoxy resin: Take 22g of propylene glycol methyl ether and 40g of butanone, stir evenly to obtain a mixed solvent; take 100g of bisphenol A type epoxy resin and 30g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heat to 125℃, stir for 2.5h, add 0.8g of tetramethylammonium chloride, heat to 155℃, stir for 5h, add 10g of isocyanate, heat to 171℃, stir for 4.5h, add the mixed solvent, stir evenly to obtain flame-retardant epoxy resin; Step 3: Preparation of the adhesive solution: Boron nitride loaded with cobalt, cobalt sulfate, acetone, and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator dimethylimidazole and curing agent 4,4-diaminodiphenol are added and mixed evenly to obtain the adhesive solution. The adhesive is composed of the following substances in parts by weight: 22 parts boron nitride loaded with cobalt, 6 parts cobalt sulfate, 28 parts acetone, 28 parts toluene, 67 parts phenolic resin, 37 parts flame retardant epoxy resin, 1.5 parts curing accelerator dimethylimidazole, and 27 parts curing agent 4,4-diaminodiphenol. Step 4: Preparation of heat-dissipating fiberglass plate for mobile phone back cover: Take 2g of chitosan and 100mL of deionized water, stir well, add 1g of phytic acid and 0.1g of acetic acid, stir for 2.5h to obtain phytic acid-chitosan composite solution; Take fiberglass cloth, clean it, and coat both sides with a phytic acid-chitosan composite solution at a coating amount of 30 g / m². 2 After drying, glass fiber cloth A is obtained; a 1 wt% cobalt sulfate aqueous solution is coated on both sides of glass fiber cloth A, with a coating amount of 20 g / m. 2After drying, fiberglass cloth B is obtained; a coating solution is applied to both sides of fiberglass cloth B, with a coating amount of 190 g / m². 2 Curing yields a prepreg; six prepregs are stacked and hot-pressed to obtain a fiberglass board; A 0.3mm thick fiberglass board is screen printed, and then a textured layer is formed on the surface by transfer printing. A film is deposited on the surface of the textured layer by physical vapor deposition. Finally, a protective varnish is applied and the board is cut to obtain a heat-dissipating fiberglass board for mobile phone back covers.

[0024] experiment: The heat-dissipating fiberglass back covers for mobile phones prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the data obtained are shown in Table 1 below: Table 1 Conclusion: The data comparison in the table shows that in Comparative Example 1, without coating with cobalt sulfate aqueous solution, the interfacial adhesion decreases, the interfacial thermal resistance increases, and the mechanical properties and heat dissipation of the fiberglass board deteriorate. In Comparative Example 2, without loading cobalt onto boron nitride, the heat dissipation of the fiberglass board deteriorates, and the mechanical properties decrease. In Comparative Example 3, without adding a magnetic field, the dispersion of cobalt-loaded boron nitride decreases, and the performance of the fiberglass board decreases in all cases. Examples 1-3 of this application involve coating with cobalt sulfate aqueous solution, where cobalt ions can coordinate with the phytic acid-chitosan composite solution and with the hydroxyl and amino groups in the adhesive, improving the bonding force between the glass fiber and the adhesive. This application improves the heat dissipation of the fiberglass board by adding boron nitride to the adhesive, as boron nitride has good thermal conductivity, thus increasing the thermal conductivity coefficient. However, boron nitride is prone to agglomeration, leading to a decrease in the mechanical properties of the fiberglass board. Loading cobalt onto boron nitride promotes the formation of thermally conductive channels, improving the heat dissipation of the fiberglass board. At the same time, cobalt is magnetic, and the loading of cobalt can make boron nitride disperse evenly under the action of a magnetic field, improving the mechanical properties and heat dissipation of the fiberglass board.

[0025] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A manufacturing process for a heat-dissipating fiberglass plate for a mobile phone back cover, characterized in that: Includes the following steps: Step 1: Take glass fiber cloth, clean it, coat both sides with phytic acid-chitosan composite solution, and dry it to obtain glass fiber cloth A; Coated with cobalt sulfate aqueous solution on both sides and dried to obtain glass fiber cloth B; coated with adhesive on both sides and left to stand for 5-10 minutes; a magnetic field was introduced, with the magnetic field direction and the glass fiber cloth B horizontal, and the magnetic field strength was 220mT; cured to obtain a prepreg; N prepregs were stacked and hot-pressed to obtain a glass fiber board. Step 2: Take a fiberglass board, perform screen printing, and then transfer the texture layer onto the surface; Step 3: A film is deposited on the surface of the textured layer by physical vapor deposition, and finally a protective varnish is applied and the layer is cut to obtain a heat-dissipating fiberglass board for the back cover of a mobile phone.

2. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 1, characterized in that: The adhesive is composed of the following substances in parts by weight: 20-24 parts cobalt-loaded boron nitride, 5-7 parts cobalt sulfate, 25-30 parts acetone, 25-30 parts toluene, 65-70 parts phenolic resin, 35-40 parts flame-retardant epoxy resin, 1-2 parts curing accelerator, and 26-28 parts curing agent.

3. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 2, characterized in that: The preparation method of the flame-retardant epoxy resin is as follows: propylene glycol methyl ether and butanone are taken and stirred evenly to obtain a mixed solvent; bisphenol A type epoxy resin and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are taken, heated to 120-130℃, stirred for 2-3 hours, tetramethylammonium chloride is added, heated to 150-160℃, stirred for 4-6 hours, isocyanate is added, heated to 170-172℃, stirred for 4-5 hours, the mixed solvent is added, and stirred evenly to obtain the flame-retardant epoxy resin.

4. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 2, characterized in that: The method for preparing cobalt-loaded boron nitride is as follows: take cobalt dichloride, cobalt oxide, and deionized water, stir evenly to obtain a mixed solution; take sodium poly(p-styrene sulfonate) modified boron nitride and deionized water, stir for 3-4 hours, add the mixed solution, stir for 1-2 hours, add 1,6-hexanediamine, stir for 10-20 minutes, let stand for 22-26 hours, wash and dry to obtain cobalt-loaded boron nitride.

5. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 4, characterized in that: The method for preparing the sodium poly(p-styrene sulfonate) modified boron nitride is as follows: Includes the following steps: S1: Take hexagonal boron nitride and sodium hydroxide, mix them evenly, react them at 180-185℃ for 7-8 hours, cool, wash and dry to obtain pretreated boron nitride; S2: Pretreated boron nitride and deionized water are ultrasonically dispersed for 6-7 hours, stirred for 2-3 hours, sodium poly(p-styrene sulfonate) is added, the temperature is raised to 50-55℃, stirred for 2-4 hours, acetic acid is added, the pH value is adjusted to 3, and the mixture is allowed to stand for 8-10 hours. After centrifugation, washing, and drying, sodium poly(p-styrene sulfonate) modified boron nitride is obtained.

6. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 1, characterized in that: The preparation method of the phytic acid-chitosan composite solution is as follows: take chitosan and deionized water, stir evenly, add phytic acid and acetic acid, stir for 2-3 hours to obtain the phytic acid-chitosan composite solution.

7. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 1, characterized in that: The concentration of the cobalt sulfate aqueous solution is 1.0wt%-1.5wt%.

8. The manufacturing process of a heat-dissipating fiberglass plate for a mobile phone back cover according to claim 1, characterized in that: The preparation method of the adhesive is as follows: cobalt-loaded boron nitride, cobalt sulfate, acetone and toluene are mixed evenly; phenolic resin and flame-retardant epoxy resin are added and mixed evenly; curing accelerator and curing agent are added and mixed evenly to obtain the adhesive.

9. A heat-dissipating fiberglass board for a mobile phone back cover prepared by the manufacturing process of a heat-dissipating fiberglass board for a mobile phone back cover according to any one of claims 1-8.

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