Glass fiber reinforced mobile phone rear cover and preparation process thereof

Abstract

The invention relates to the technical field of electronic product shells, in particular to a glass fiber reinforced mobile phone rear cover and a preparation process thereof. The preparation method comprises the following steps: 1, uniformly mixing epoxy resin, cardanol-based epoxy resin, organic silicon modified benzoxazine, a curing agent and an accelerant to obtain an epoxy resin glue solution; 2, coating the epoxy resin glue solution on the surface of glass fiber cloth, and curing to obtain a glass fiber prepreg; 3, a plurality of glass fiber prepregs are taken to be stacked and laid, integrated forming is achieved through hot pressing, and a laminated board is obtained; 4, uniformly mixing the epoxy resin glue solution, the modified molybdenum disulfide and acetone to obtain a protective coating; and 5, sequentially arranging a priming layer, a transfer printing layer and a packaging layer on the laminated board, spraying a protective coating, and curing to form a protective layer to obtain the mobile phone rear cover.

Description

Technical Field

[0001] This invention relates to the field of electronic product casing technology, specifically to a glass fiber reinforced mobile phone back cover and its manufacturing process. Background Technology

[0002] With the widespread adoption of smartphones and continuous technological advancements, the performance requirements for mobile phone casing materials are constantly increasing. Users demand not only aesthetics and lightweight design for phone back covers, but also good drop resistance, abrasion resistance, and thermal stability. While traditional plastics and metals meet these requirements to some extent, they have limitations in terms of strength, rigidity, and weight. To address these issues, glass fiber reinforced materials are gradually becoming an ideal choice.

[0003] Glass fiber reinforced materials are widely used in aerospace, automotive, and electronics industries due to their excellent mechanical properties, lightweight nature, and corrosion resistance. In mobile phone back covers, the addition of glass fiber effectively improves the material's strength and rigidity while maintaining a lighter weight, thereby enhancing the overall performance and user experience of the phone. Although glass fiber reinforced materials have high strength, their toughness is relatively low, making them prone to brittle fracture under strong impact.

[0004] Therefore, we propose a glass fiber reinforced mobile phone back cover and its manufacturing process. Summary of the Invention

[0005] The purpose of this invention is to provide a glass fiber reinforced mobile phone back cover and its manufacturing process, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A manufacturing process for a glass fiber reinforced mobile phone back cover includes the following steps: Step 1: Mix epoxy resin, cashew phenol-based epoxy resin, organosilicon-modified benzoxazine, curing agent and accelerator evenly to obtain epoxy resin adhesive; Step 2: Apply epoxy resin solution to the surface of fiberglass cloth and cure to obtain fiberglass prepreg; Step 3: Take several sheets of fiberglass prepreg and stack them together, then heat press them to form a single piece, thus obtaining a laminate. Step 4: Mix the epoxy resin, modified molybdenum disulfide, and acetone evenly to obtain the protective coating; Step 5: On the laminate, the base layer, pad printing layer, and encapsulation layer are applied in sequence, and then a protective coating is sprayed on. After curing, a protective layer is formed, resulting in the back cover of the mobile phone.

[0007] Furthermore, the epoxy resin adhesive is composed of the following components, in parts by weight: 60-80 parts epoxy resin, 10-20 parts cashew phenol-based epoxy resin, 20-30 parts organosilicon-modified benzoxazine, 10-15 parts accelerator, and 12-18 parts curing agent.

[0008] Furthermore, the accelerator is 2-ethyl-4-methylimidazole.

[0009] Furthermore, the preparation method of the organosilicon-modified benzoxazine is as follows: Step A: Under nitrogen protection, cashew phenol acetate and boron-containing hydrogen silicone oil are mixed evenly, and chloroplatinic acid-isopropanol solution is added. The mixture is reacted at 70-80℃ for 8-10 hours to obtain the intermediate. Step B: Under nitrogen protection, the intermediate and hydrochloric acid solution are mixed evenly and hydrolyzed at 90-100℃ for 6-8 hours to obtain organosilicon-modified cashew nut powder. Step C: Mix toluene and chloroform evenly in an ice-water bath, add paraformaldehyde, octanediamine and organosilicon-modified cashew phenol, transfer to an oil bath under nitrogen protection, reflux at 85-95℃ for 8-10 hours, cool to room temperature, and obtain organosilicon-modified benzoxazine by rotary evaporation.

[0010] Furthermore, the boron- and hydrogen-containing silicone oil is prepared according to the method of Example 1 in Chinese Invention Patent CN110078927B.

[0011] Further, in step A, the mass ratio of cashew phenol acetate to boron-containing and hydrogen-containing silicone oil is 1:(3-5).

[0012] Further, in step A, the mass of the chloroplatinic acid-isopropanol solution, measured in Pt, is 2-5 ppm of the total mass of cashew phenol acetate and boron- and hydrogen-containing silicone oil.

[0013] Furthermore, the preparation method of the cashew phenol acetate is as follows: cashew phenol and p-toluenesulfonic acid are mixed evenly, acetic anhydride is added, and the mixture is reacted at room temperature for 22-24 hours. After washing until neutral, the mixture is distilled under reduced pressure to obtain cashew phenol acetate.

[0014] Further, the molar ratio of cashew phenol, acetic anhydride and toluenesulfonic acid is 1:(1.0-1.2):(0.013-0.015).

[0015] Further, in step B, the mass ratio of the intermediate to the hydrochloric acid solution is 1:(2-4), and the concentration of the hydrochloric acid solution is 1 mol / L.

[0016] Furthermore, in step C, the volume ratio of toluene to chloroform is 2:1, and the ratio of octanediamine to toluene is 1:(20-25) g / mL.

[0017] Furthermore, in step C, the mass ratio of paraformaldehyde, octyldiamine, and organosilicon-modified cashew phenol is 1:(4-6):(2-4).

[0018] Furthermore, the protective coating is composed of the following components, in parts by weight: 60-80 parts epoxy resin adhesive, 5-15 parts modified molybdenum disulfide, and 30-50 parts acetone.

[0019] Furthermore, the method for preparing the modified molybdenum disulfide is as follows: Terminal epoxy polydimethylsiloxane was dissolved in isopropanol, and N-aminoethyl-3-aminopropyltriethoxysilane was added. The mixture was reacted at 45-55℃ for 2-4 hours to obtain a modifier. Molybdenum disulfide was ultrasonically dispersed in deionized water, and tetraethyl orthosilicate was added. Ammonia was added to adjust the pH to 9.5-9.7, and the mixture was reacted at 55-65℃ for 10-12 hours. The modifier was then added, and the mixture was reacted for 22-24 hours. After centrifugation, washing, and drying, modified molybdenum disulfide was obtained.

[0020] Furthermore, the molar ratio of the terminal epoxy polydimethylsiloxane to N-aminoethyl-3-aminopropyltriethoxysilane is 1:(2.0-2.2).

[0021] Further, the mass ratio of molybdenum disulfide, deionized water and tetraethyl orthosilicate is 1:(100-120):(15-20).

[0022] Furthermore, the mass of the modifier is 0.1-0.3 times the mass of tetraethyl orthosilicate.

[0023] Furthermore, in step two, the curing process conditions are curing at 100-110℃ for 3-5 minutes.

[0024] Furthermore, in step three, the hot pressing process conditions are: temperature of 200-220℃ and pressure of 5-10MPa.

[0025] Furthermore, the thickness of the protective layer is 20-50 μm.

[0026] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention relates to a glass fiber reinforced mobile phone back cover and its preparation process, wherein cashew phenol acetate is prepared by reacting cashew phenol with acetic anhydride, which effectively protects its phenolic hydroxyl groups and avoids side reactions and catalyst poisoning failure in subsequent reactions; then, the unsaturated bonds on the long side chain of cashew phenol acetate are used to carry out a hydrosilylation reaction with boron-containing and hydrogen-containing silicone oil to graft boron and siloxane onto the cashew phenol compound, and boron-containing siloxane cashew phenol is obtained by hydrolysis protection, namely organosilicon modified cashew phenol; Finally, using saturated organosilicon-modified cashew phenol as the phenol source and octanediamine as the amine source, a compound containing a six-membered heterocyclic structure, namely organosilicon-modified benzoxazine, was synthesized by reacting with paraformaldehyde via the Mannich reaction. By introducing long alkyl chains and organosilicon structures, the surface energy of the composite material was significantly reduced, giving it excellent hydrophobicity. The introduction of the rigid benzoxazine structure endowed the material with higher thermal stability and heat oxidation resistance. Due to the introduction of flexible long alkyl chains and organosilicon segments, a "rigid-flexible" structure was formed in the rigid network. This structure can effectively prevent crack propagation and absorb impact energy through plastic deformation, thereby significantly improving the toughness, impact strength, and crack resistance of the material. In addition, the introduction of boron further improved high-temperature stability and flame retardancy.

[0027] 2. The present invention relates to a glass fiber reinforced mobile phone back cover and its preparation process, wherein a siloxane-terminated modifier is prepared by reacting terminal epoxy polydimethylsiloxane with N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane through a ring-opening reaction; by loading silicon dioxide onto molybdenum disulfide to form a micro-nano hierarchical structure, the wear resistance of the protective layer is significantly improved; at the same time, the modifier is added to modify the silicon dioxide-molybdenum disulfide, which not only improves the compatibility and dispersibility of inorganic fillers in epoxy resin, but also further improves the hydrophobicity of the protective layer, giving it superhydrophobicity. Detailed Implementation

[0028] 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.

[0029] It should be noted that, unless otherwise specified, all the following quantities are by weight. There are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: epoxy resin: bisphenol A type epoxy resin, grade E-51; cashew phenol-based epoxy resin: model YLE-200S, purchased from Hunan Servi New Material Technology Co., Ltd.; curing agent: 4,4-diaminodiphenyl sulfone; accelerator: 2-ethyl-4-methylimidazole; boron-containing hydrogen-containing silicone oil prepared according to the method of Example 1 in Chinese Invention Patent CN110078927B; molybdenum disulfide: model Brofos-MoS2-50, purchased from Bohuas Nanotechnology (Ningbo) Co., Ltd.; terminal epoxy polydimethylsiloxane: grade UC-726-6K, purchased from Jiaxing United Chemical Co., Ltd.; undercoat: PU502, purchased from Guangzhou Guanzhi New Material Technology Co., Ltd.; pad printing layer: MG-PAD pad printing ink; encapsulation layer: transparent epoxy resin adhesive layer, model LOCTITE EA E-30CL.

[0030] Example 1: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: Step 1: Mix 60 parts epoxy resin, 10 parts cashew phenol-based epoxy resin, 20 parts organosilicon-modified benzoxazine, 12 parts curing agent and 10 parts accelerator evenly to obtain epoxy resin adhesive. Step 2: Apply epoxy resin solution to the surface of the fiberglass cloth (coating amount on one side is 150g / m²). 2 The glass fiber prepreg is cured at 100°C for 5 minutes to obtain the glass fiber prepreg. Step 3: Take three pieces of fiberglass prepreg and stack them together. Then, hot press them to form a single piece (temperature 200℃, pressure 10MPa) to obtain a laminate. Step 4: Mix 60 parts epoxy resin liquid, 5 parts modified molybdenum disulfide and 30 parts acetone evenly to obtain a protective coating; Step 4: On the laminate, the base layer, pad printing layer, and encapsulation layer are applied in sequence, and then a protective coating is sprayed on. After curing, a protective layer is formed, resulting in the back cover of the mobile phone. The preparation method of organosilicon-modified benzoxazine is as follows: Step A: Mix cashew phenol and p-toluenesulfonic acid evenly, add acetic anhydride, react at room temperature for 22 h, wash the product with 5 wt% sodium bicarbonate solution and deionized water until neutral, remove water by vacuum distillation to obtain cashew phenol acetate; the molar ratio of cashew phenol, acetic anhydride and toluenesulfonic acid is 1:1:0.013. Under nitrogen protection, 20 parts of cashew nut acetate and 60 parts of boron-containing and hydrogen-containing silicone oil were mixed evenly, and a chloroplatinic acid-isopropanol solution was added. The mixture was reacted at 70°C for 8 hours. Unreacted raw materials were removed by vacuum distillation. The mixture was washed with dichloromethane, filtered, and rotary evaporated to obtain an intermediate. The mass of the chloroplatinic acid-isopropanol solution, measured in Pt, was 2-5 ppm of the total mass of cashew nut acetate and boron-containing and hydrogen-containing silicone oil. Step B: Under nitrogen protection, 20 parts of intermediate and 40 parts of 1 mol / L hydrochloric acid solution were mixed evenly and hydrolyzed at 90℃ for 6 hours. After cooling to room temperature, the product was extracted and distilled to obtain organosilicon-modified cashew nut powder. Step C: Mix 800 mL of toluene and 400 mL of chloroform evenly in an ice-water bath, add 10 parts of paraformaldehyde, 40 parts of octanediamine and 20 parts of organosilicon-modified cashew nut shell powder, transfer to an oil bath under nitrogen protection, reflux at 85 °C for 8 h, cool to room temperature, and obtain organosilicon-modified benzoxazine by rotary evaporation. The preparation method of modified molybdenum disulfide is as follows: Terminal epoxy polydimethylsiloxane was dissolved in isopropanol, and N-aminoethyl-3-aminopropyltriethoxysilane was added. The mixture was reacted at 45°C for 2 hours to obtain the modifier. The molar ratio of terminal epoxy polydimethylsiloxane to N-aminoethyl-3-aminopropyltriethoxysilane was 1:2. Five parts of molybdenum disulfide were ultrasonically dispersed in 500 parts of deionized water, 75 parts of tetraethyl orthosilicate were added, and ammonia was added to adjust the pH to 9.5. The mixture was reacted at 55°C for 10 hours, and then 22.5 parts of modifier were added. The mixture was reacted for 22 hours. After centrifugation, washing and drying, modified molybdenum disulfide was obtained. Example 2: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: Step 1: Mix 70 parts epoxy resin, 15 parts cashew phenol-based epoxy resin, 25 parts organosilicon-modified benzoxazine, 16 parts curing agent and 12 parts accelerator evenly to obtain epoxy resin adhesive. Step 2: Apply epoxy resin solution to the surface of the fiberglass cloth (coating amount on one side is 180g / m²). 2 The glass fiber prepreg was cured at 105°C for 4 minutes to obtain the glass fiber prepreg. Step 3: Take three pieces of fiberglass prepreg and stack them together. Then, hot press them to form a single piece (temperature 210℃, pressure 8MPa) to obtain a laminate. Step 4: Mix 70 parts epoxy resin liquid, 10 parts modified molybdenum disulfide and 40 parts acetone evenly to obtain a protective coating; Step 4: On the laminate, the base layer, pad printing layer, and encapsulation layer are applied in sequence, and then a protective coating is sprayed on. After curing, a protective layer is formed, resulting in the back cover of the mobile phone. The preparation method of organosilicon-modified benzoxazine is as follows: Step A: Mix cashew phenol and p-toluenesulfonic acid evenly, add acetic anhydride, react at room temperature for 22-24 h, wash the product with 5 wt% sodium bicarbonate solution and deionized water until neutral, remove water by vacuum distillation to obtain cashew phenol acetate; the molar ratio of cashew phenol, acetic anhydride and toluenesulfonic acid is 1:1.1:0.014. Under nitrogen protection, 15 parts of cashew nut acetate and 60 parts of boron-containing and hydrogen-containing silicone oil were mixed evenly, and a chloroplatinic acid-isopropanol solution was added. The mixture was reacted at 75°C for 9 hours. Unreacted raw materials were removed by vacuum distillation. The mixture was washed with dichloromethane, filtered, and rotary evaporated to obtain an intermediate. The mass of the chloroplatinic acid-isopropanol solution, measured in Pt, was 3 ppm of the total mass of cashew nut acetate and boron-containing and hydrogen-containing silicone oil. Step B: Under nitrogen protection, 15 parts of intermediate and 45 parts of 1 mol / L hydrochloric acid solution were mixed evenly and hydrolyzed at 95℃ for 7 h. After cooling to room temperature, the product was extracted and distilled to obtain organosilicon-modified cashew nut powder. Step C: Mix 550 mL of toluene and 275 mL of chloroform evenly in an ice-water bath, add 5 parts of paraformaldehyde, 25 parts of octanediamine and 15 parts of organosilicon-modified cashew nut shell powder, transfer to an oil bath under nitrogen protection, reflux at 90 °C for 9 h, cool to room temperature, and obtain organosilicon-modified benzoxazine by rotary evaporation. The preparation method of modified molybdenum disulfide is as follows: Terminal epoxy polydimethylsiloxane was dissolved in isopropanol, and N-aminoethyl-3-aminopropyltriethoxysilane was added. The mixture was reacted at 50°C for 3 hours to obtain the modifier. The molar ratio of terminal epoxy polydimethylsiloxane to N-aminoethyl-3-aminopropyltriethoxysilane was 1:2.1. Ten parts of molybdenum disulfide were ultrasonically dispersed in 1100 mL of deionized water, 180 parts of tetraethyl orthosilicate were added, and ammonia was added to adjust the pH to 9.6. The mixture was reacted at 60 °C for 11 h, and then 36 parts of modifier were added. The mixture was reacted for 23 h. After centrifugation, washing and drying, modified molybdenum disulfide was obtained.

[0031] Example 3: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: Step 1: Mix 80 parts epoxy resin, 20 parts cashew phenol-based epoxy resin, 30 parts organosilicon-modified benzoxazine, 18 parts curing agent and 15 parts accelerator evenly to obtain epoxy resin adhesive. Step 2: Apply epoxy resin solution to the surface of the fiberglass cloth (coating amount on one side is 200g / m²). 2 The glass fiber prepreg is cured at 110°C for 3 minutes to obtain the glass fiber prepreg. Step 3: Take three pieces of fiberglass prepreg and stack them together. Then, hot press them to form a single piece (temperature 220℃, pressure 5MPa) to obtain a laminate. Step 4: Mix 80 parts epoxy resin liquid, 15 parts modified molybdenum disulfide and 50 parts acetone evenly to obtain a protective coating; Step 4: On the laminate, the base layer, pad printing layer, and encapsulation layer are applied in sequence, and then a protective coating is sprayed on. After curing, a protective layer is formed, resulting in the back cover of the mobile phone. The preparation method of organosilicon-modified benzoxazine is as follows: Step A: Mix cashew phenol and p-toluenesulfonic acid evenly, add acetic anhydride, react at room temperature for 24 h, wash the product with 5 wt% sodium bicarbonate solution and deionized water until neutral, remove water by vacuum distillation to obtain cashew phenol acetate; the molar ratio of cashew phenol, acetic anhydride and toluenesulfonic acid is 1:1.2:0.015; Under nitrogen protection, 30 parts of cashew nut acetate and 150 parts of boron-containing and hydrogen-containing silicone oil were mixed evenly, and a chloroplatinic acid-isopropanol solution was added. The mixture was reacted at 80°C for 10 hours. Unreacted raw materials were removed by vacuum distillation. The mixture was washed with dichloromethane, filtered, and rotary evaporated to obtain an intermediate. The mass of the chloroplatinic acid-isopropanol solution, measured in Pt, was 5 ppm of the total mass of cashew nut acetate and boron-containing and hydrogen-containing silicone oil. Step B: Under nitrogen protection, 30 parts of intermediate and 60 parts of 1 mol / L hydrochloric acid solution were mixed evenly and hydrolyzed at 100℃ for 8 hours. After cooling to room temperature, the product was extracted and distilled to obtain organosilicon-modified cashew nut powder. Step C: Mix 1125 mL of toluene and 562 mL of chloroform evenly in an ice-water bath, add 7.5 parts of paraformaldehyde, 45 parts of octanediamine and 30 parts of organosilicon-modified cashew nut shell powder, transfer to an oil bath under nitrogen protection, reflux at 95 °C for 10 h, cool to room temperature, and obtain organosilicon-modified benzoxazine by rotary evaporation; The preparation method of modified molybdenum disulfide is as follows: Terminal epoxy polydimethylsiloxane was dissolved in isopropanol, and N-aminoethyl-3-aminopropyltriethoxysilane was added. The mixture was reacted at 55°C for 4 hours to obtain a modifier. The molar ratio of terminal epoxy polydimethylsiloxane to N-aminoethyl-3-aminopropyltriethoxysilane was 1:2.2. 15 parts of molybdenum disulfide were ultrasonically dispersed in 1800 parts of deionized water, 300 parts of tetraethyl orthosilicate were added, and ammonia was added to adjust the pH to 9.7. The mixture was reacted at 65°C for 12 hours, and 30 parts of the modifier were added. The mixture was reacted for 24 hours. After centrifugation, washing, and drying, modified molybdenum disulfide was obtained.

[0032] Comparative Example 1: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: The preparation method of organosilicon-modified cashew nut shell powder is as follows: Step A: Mix cashew phenol and p-toluenesulfonic acid evenly, add acetic anhydride, react at room temperature for 22-24 h, wash the product with 5 wt% sodium bicarbonate solution and deionized water until neutral, remove water by vacuum distillation to obtain cashew phenol acetate; the molar ratio of cashew phenol, acetic anhydride and toluenesulfonic acid is 1:1.1:0.014. Under nitrogen protection, 15 parts of cashew nut acetate and 60 parts of boron-containing and hydrogen-containing silicone oil were mixed evenly, and a chloroplatinic acid-isopropanol solution was added. The mixture was reacted at 75°C for 9 hours. Unreacted raw materials were removed by vacuum distillation. The mixture was washed with dichloromethane, filtered, and rotary evaporated to obtain an intermediate. The mass of the chloroplatinic acid-isopropanol solution, measured in Pt, was 3 ppm of the total mass of cashew nut acetate and boron-containing and hydrogen-containing silicone oil. Step B: Under nitrogen protection, 15 parts of intermediate and 45 parts of 1 mol / L hydrochloric acid solution were mixed evenly and hydrolyzed at 95℃ for 7 h. After cooling to room temperature, the product was extracted and distilled to obtain organosilicon-modified cashew nut powder. Compared with Example 2, Comparative Example 1 does not include step C, and replaces the organosilicon-modified benzoxazine with the same mass of organosilicon-modified cashew phenol; the other steps are the same as in Example 2.

[0033] Comparative Example 2: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: Compared with Example 2, in step C of Comparative Example 2, the organosilicon-modified cashew phenol was replaced with the same mass of cashew phenol, and the other steps were the same as in Example 2.

[0034] Comparative Example 3: A manufacturing process for a glass fiber reinforced mobile phone back cover, comprising the following processes: The preparation method of modified molybdenum disulfide is as follows: Ten parts of molybdenum disulfide were ultrasonically dispersed in 1100 mL of deionized water, 180 parts of tetraethyl orthosilicate were added, and ammonia was added to adjust the pH to 9.6. The mixture was reacted at 60 °C for 11 h. After centrifugation, washing and drying, modified molybdenum disulfide was obtained.

[0035] Compared with Example 2, Comparative Example 3 did not add any modifier, and the other steps were the same as in Example 2.

[0036] Experiment: Samples were prepared from the phone back covers obtained in Examples 1-3 and Comparative Examples 1-3. Their performance was tested, and the results were recorded. Moisture and heat resistance: Tensile strength was tested according to GB / T 1040.4-2006 at a tensile rate of 50 mm / min. The sample size was 2 mm × 25 mm × 150 mm. The sample was immersed in water at 85°C for 60 minutes, and the tensile strength was measured again to evaluate its moisture and heat resistance. Impact strength: Tested according to GB / T 1843-2008. Water contact angle: Tested using a 2 μL droplet of deionized water.

[0037] The test results are shown in Table 1.

[0038] Table 1 Performance test results of glass fiber reinforced mobile phone back covers Based on the data in the table above, the following conclusions can be clearly drawn: Combining Examples 1-3 and Comparative Examples 1-3, it can be seen that the mobile phone back cover prepared by the present invention has excellent mechanical properties, heat resistance and hydrophobic properties; Comparative Example 1 did not introduce a rigid benzoxazine structure and long alkyl chain, so the mechanical properties and thermal stability of the material decreased; Comparative Example 2 did not introduce boron-containing and hydrogen-containing silicone oil, so the tensile properties of the material decreased; Comparative Example 3 did not introduce a modifier, so the surface hydrophobic properties of the material decreased.

[0039] 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 glass fiber reinforced mobile phone back cover, characterized in that: Includes the following steps: Step 1: Mix epoxy resin, cashew phenol-based epoxy resin, organosilicon-modified benzoxazine, curing agent and accelerator evenly to obtain epoxy resin adhesive; Step 2: Apply epoxy resin solution to the surface of fiberglass cloth and cure to obtain fiberglass prepreg; Step 3: Take several sheets of fiberglass prepreg and stack them together, then heat press them to form a single piece, thus obtaining a laminate. Step 4: Mix the epoxy resin, modified molybdenum disulfide, and acetone evenly to obtain the protective coating; Step 5: On the laminate, the base layer, pad printing layer, and encapsulation layer are applied in sequence, and then a protective coating is sprayed on. After curing, a protective layer is formed, resulting in the back cover of the mobile phone.

2. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 1, characterized in that: The epoxy resin adhesive is composed of the following components, in parts by weight: 60-80 parts epoxy resin, 10-20 parts cashew phenol-based epoxy resin, 20-30 parts organosilicon-modified benzoxazine, 10-15 parts accelerator, and 12-18 parts curing agent.

3. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 2, characterized in that: The preparation method of the organosilicon-modified benzoxazine is as follows: Step A: Under nitrogen protection, cashew phenol acetate and boron-containing and hydrogen-containing silicone oil are mixed evenly, and chloroplatinic acid-isopropanol solution is added. The mixture is reacted at 70-80℃ for 8-10 hours to obtain the intermediate. Step B: Under nitrogen protection, the intermediate and hydrochloric acid solution are mixed evenly and hydrolyzed at 90-100℃ for 6-8 hours to obtain organosilicon-modified cashew nut powder. Step C: Mix toluene and chloroform evenly in an ice-water bath, add paraformaldehyde, dodecylamine and organosilicon-modified cashew phenol, transfer to an oil bath under nitrogen protection, reflux at 85-95℃ for 8-10 hours, cool to room temperature, and obtain organosilicon-modified benzoxazine by rotary evaporation.

4. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 3, characterized in that: The preparation method of the cashew phenol acetate is as follows: Cashew phenol and p-toluenesulfonic acid are mixed evenly, acetic anhydride is added, and the mixture is reacted at room temperature for 22-24 hours. After washing until neutral, the mixture is distilled under reduced pressure to obtain cashew phenol acetate.

5. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 1, characterized in that: In step two, the curing process conditions are curing at 100-110℃ for 3-5 minutes.

6. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 1, characterized in that: In step three, the hot pressing process conditions are: temperature 200-220℃ and pressure 5-10MPa.

7. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 1, characterized in that: The protective coating is composed of the following components, in parts by weight: 60-80 parts epoxy resin, 5-15 parts modified molybdenum disulfide, and 30-50 parts acetone.

8. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 7, characterized in that: The modified molybdenum disulfide is prepared as follows: Terminal epoxy polydimethylsiloxane was dissolved in isopropanol, and N-aminoethyl-3-aminopropyltriethoxysilane was added. The mixture was reacted at 45-55℃ for 2-4 hours to obtain a modifier. Molybdenum disulfide was ultrasonically dispersed in deionized water, and tetraethyl orthosilicate was added. Ammonia was added to adjust the pH to 9.5-9.7, and the mixture was reacted at 55-65℃ for 10-12 hours. The modifier was then added, and the mixture was reacted for 22-24 hours. After centrifugation, washing, and drying, modified molybdenum disulfide was obtained.

9. The manufacturing process of a glass fiber reinforced mobile phone back cover according to claim 8, characterized in that: The molar ratio of the terminal epoxy polydimethylsiloxane to N-aminoethyl-3-aminopropyltriethoxysilane is 1:(2.0-2.2).

10. A glass fiber reinforced mobile phone back cover prepared by the manufacturing process according to any one of claims 1-9.

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