Mobile phone rear cover laminated board with improved puncture resistance and preparation method of mobile phone rear cover laminated board

Abstract

The invention relates to the technical field of electronic product shells, in particular to a mobile phone rear cover laminated board with improved puncture resistance and a preparation method of the mobile phone rear cover laminated board. The mobile phone rear cover laminated board sequentially comprises a glass fiber prepreg layer, an anti-puncture layer, a glass fiber prepreg layer, a priming layer, a transfer printing layer, a packaging layer and a protective layer from inside to outside, and the anti-puncture layer and the glass fiber prepreg layer are cured together through an epoxy resin glue solution. The epoxy resin glue solution is prepared from the following components in parts by weight: 30 to 50 parts of polyamide modified epoxy resin, 20 to 40 parts of phenoxy resin, 45 to 65 parts of bisphenol A type epoxy resin, 10 to 15 parts of isocyanate modified epoxy resin, 6 to 12 parts of dicyandiamide and 5 to 10 parts of epoxy accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic product housings, and in particular to a mobile phone back cover laminate with improved puncture resistance and a preparation method thereof. Background Art

[0002] The back cover of a mobile phone is one of its accessories, providing some protection for the phone's internal structure. Among the various materials used for mobile phone back covers, fiberglass is widely used due to its excellent strength and rigidity. However, as an inorganic fiber bundle, fiberglass is generally brittle, resulting in poor drop resistance.

[0003] To address this issue, other puncture-resistant materials are often laminated with glass fiber. Existing fiber materials with excellent puncture resistance include ultra-high molecular weight polyethylene (UPE), Kevlar, and poly(p-phenylene benzobisoxazole) (PBO). While UPE and PBO offer excellent puncture resistance, their poor interfacial properties can easily lead to delamination in the composite materials. Furthermore, laser processing can result in long production times and blackened edges after cutting, impacting the aesthetics and performance of the finished product. Kevlar's yellow color presents certain limitations in practical applications, and UPE can easily degrade the flexural properties of mobile phone back covers during use.

[0004] The emergence of Cordura not only improves the puncture resistance of the board, but also does not reduce the bending performance of the back cover of the mobile phone. In addition, its original color is white and has a wide range of applications. After many tests, the material can be processed using CNC machine tools and has a certain ability to cover cloth textures without the stripe marks of other materials.

[0005] Therefore, we propose a mobile phone back cover laminate with improved puncture resistance and a preparation method thereof. Summary of the Invention

[0006] The purpose of the present invention is to provide a mobile phone back cover laminate with improved puncture resistance and a preparation method thereof, so as to solve the problems raised in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions: A mobile phone back cover laminate with improved puncture resistance. The mobile phone back cover laminate comprises, from the inside out, a glass fiber prepreg layer, an anti-puncture layer, a glass fiber prepreg layer, a primer layer, a pad printing layer, an encapsulation layer, and a protective layer. The anti-puncture layer and the glass fiber prepreg layer are cured together by epoxy resin glue.

[0008] Furthermore, the glass fiber prepreg layer is composed of glass fiber cloth impregnated with epoxy resin glue.

[0009] Furthermore, the preparation method of the epoxy resin glue is as follows: Step A: Under nitrogen protection, heat and melt acrylic rosin, add magnolol diglycidyl ether under the catalysis of triethylamine, and react at 120-130°C for 6-8 hours to obtain a hydroxyl-containing epoxy compound; Step B: Under nitrogen protection, amino-terminated polydimethylsiloxane, terephthaloyl chloride and chloroform are mixed uniformly, triethylamine is added, and the mixture is reacted in an ice bath for 2-4 hours. A hydroxyl-containing epoxy compound is then added, and the mixture is reacted at room temperature for 3-5 hours. After extraction and drying, a polyamide-modified epoxy resin is obtained; Step C: uniformly mixing polyamide-modified epoxy resin, phenoxy resin, bisphenol A epoxy resin, isocyanate-modified epoxy resin, dicyandiamide and epoxy accelerator to obtain epoxy resin glue.

[0010] Furthermore, the epoxy resin glue comprises the following components by weight: 30-50 parts of polyamide-modified epoxy resin, 20-40 parts of phenoxy resin, 45-65 parts of bisphenol A epoxy resin, 10-15 parts of isocyanate-modified epoxy resin, 6-12 parts of dicyandiamide, and 5-10 parts of epoxy accelerator.

[0011] Furthermore, in step A, the molar ratio of acrylic rosin to magnolol diglycidyl ether is 1:2.

[0012] Furthermore, the preparation method of the magnolol diglycidyl ether is as follows: Under nitrogen protection, magnolol, epichlorohydrin and benzyltriethylammonium chloride were mixed evenly, reacted at 80-90°C for 3-5 hours, cooled to 40-50°C, sodium hydroxide solution was added, and the reaction was continued for 1-3 hours. After filtration, washing and drying, magnolol diglycidyl ether was obtained.

[0013] Furthermore, the mass ratio of magnolol, epichlorohydrin, benzyltriethylammonium chloride and sodium hydroxide solution is 1: (2 3): (0.05 0.08): (0.5 1.0), and the concentration of the sodium hydroxide solution is 30-40 wt%.

[0014] Furthermore, in the step B, the amount of triethylamine used is 1-3% of the total mass of rosin acrylate and magnolol diglycidyl ether.

[0015] Furthermore, in the step B, the molar ratio of amino-terminated polydimethylsiloxane to terephthaloyl chloride is 1:(2.0-2.2).

[0016] Furthermore, in the step B, the amount of triethylamine used is 3-5% of the total mass of the amino-terminated polydimethylsiloxane and terephthaloyl chloride.

[0017] Furthermore, in step B, the molar ratio of the hydroxyl-containing epoxy compound to terephthaloyl chloride is 1:(0.5-1.0).

[0018] Furthermore, the epoxy accelerator is 2-ethyl-4-methylimidazole.

[0019] Furthermore, the puncture-resistant layer is composed of Cordura fiber woven cloth impregnated with epoxy resin glue.

[0020] Furthermore, the connecting layer is one of an epoxy resin adhesive layer, a polyurethane adhesive layer, and an acrylic adhesive layer.

[0021] Furthermore, the transfer printing layer is one of a textured epoxy resin adhesive layer, a polyurethane adhesive layer, and an acrylic adhesive layer.

[0022] Furthermore, the encapsulation layer is one of a transparent epoxy resin adhesive layer, a polyurethane adhesive layer, and an acrylic adhesive layer.

[0023] Furthermore, the protective layer is one of acrylic resin, polyurethane, glass, and acrylic.

[0024] A method for preparing a mobile phone back cover laminate with improved puncture resistance comprises the following steps: Step S1: evenly coating the epoxy resin glue on the surface of the glass fiber cloth, and drying at 110-120° C. for 10-20 minutes to obtain a glass fiber prepreg layer; Step S2: evenly coating the surface of the Cordura fiber woven fabric with epoxy resin glue, and drying at 110-120° C. for 10-20 minutes to obtain a puncture-resistant layer; Step S3: stacking the glass fiber prepreg layer, the puncture-resistant layer, and the glass fiber prepreg layer in sequence, and producing a laminate through a hot pressing process; Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate.

[0025] In the above technical solution, the puncture-resistant layer is made of Cordura fiber woven cloth, and the puncture-resistant layer and glass fiber prepreg layer are cured together with epoxy resin glue. A base layer, pad printing layer, encapsulation layer, and protective layer are sequentially arranged on the laminate, thereby improving the structure of the electronic product back cover, improving toughness, strong drop resistance, and good post-processing properties. The base layer has a connecting function, allowing the pad printing layer to be firmly cured on the laminate. The encapsulation layer has an encapsulating function, which can encapsulate the pad printing layer in the base layer to avoid interference between different layers. The protective layer has excellent wear resistance, which increases the service life of the electronic product back cover.

[0026] Furthermore, the thickness of the glass fiber prepreg layer and the puncture-resistant layer are both 0.03 mm to 0.20 mm.

[0027] Furthermore, the temperature of the hot pressing process is 160-180° C. and the pressure is 5-10 MPa.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention discloses a laminated sheet for a mobile phone back cover with improved puncture resistance and a method for preparing the same. Under test conditions of equivalent thickness, the puncture strength of pure Cordura fiber is superior to that of pure glass fiber, resulting in better puncture resistance and a lighter density than aramid. Compared to the traditional four-layer glass fiber sheet structure, this solution innovatively incorporates highly puncture-resistant Cordura fiber as the middle layer, creating a "single-layer glass fiber + Cordura + single-layer glass fiber" sandwich structure. This significantly improves puncture resistance while maintaining minimal difference in bending strength.

[0029] 2. The present invention discloses a mobile phone back cover laminate with improved puncture resistance and a preparation method thereof. Using epichlorohydrin and the hydrophobic bio-based compound magnolol as raw materials, a bio-based epoxy resin containing a biphenyl structure, namely magnolol diglycidyl ether, is obtained, which can effectively improve the heat resistance and mechanical strength of the resin system. By controlling the molar ratio of acrylic rosin to magnolol diglycidyl ether to be 1:2, a ring-opening reaction occurs to generate hydroxyl groups, thereby obtaining a hydroxyl-containing epoxy compound. Simultaneously, a cyclic terpene structure is introduced to increase the rigidity and polarity of the resin, thereby improving the adhesion, cohesion, and heat resistance of the epoxy resin glue. An aromatic polyamide containing hydrophobic siloxane segments and epoxy structures was synthesized using a one-pot polycondensation method using amino-terminated polydimethylsiloxane (ATPDMS) and a hydroxyl-containing epoxy compound as raw materials. This aromatic polyamide exhibits excellent compatibility with Cordura fiber, ensuring excellent interfacial compatibility and bonding strength between the fiber and the resin matrix, thereby fully utilizing the high puncture strength of Cordura. The epoxy resin adhesive in this invention is prepared from a polyamide-modified epoxy resin, a phenoxy resin, a bisphenol A-type epoxy resin, an isocyanate-modified epoxy resin, dicyandiamide, diaminophenylsulfone, and an epoxy accelerator, and exhibits excellent heat resistance and adhesion. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] In this embodiment, the phenoxy resin: brand SFD-30AMX40, purchased from Suzhou Senfida Chemical Co., Ltd.; bisphenol A type epoxy resin: brand E-51, purchased from Baling Petrochemical, model CYD-128; isocyanate modified epoxy resin: brand Asahi Kasei A-IME AER4152; acrylic rosin purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.; amino-terminated polydimethylsiloxane: model A850310, purchased from Shanghai Macklin; Cordura fiber woven cloth: Cordura 1000D nylon, thickness 0.1 mm, purchased from Dongguan Tongli Textile Co., Ltd.; glass fiber cloth: alkali-free glass roving, thickness 0.1 mm, purchased from Taizhou Zhongsheng Glass Fiber Products Co., Ltd.; base layer: PU502; transfer printing layer: textured epoxy resin adhesive layer, Loctite EA 3423 epoxy resin adhesive; encapsulation layer: transparent epoxy resin adhesive layer, model LOCTITE EA E-30CL; protective layer: acrylic resin, model FD-508PA, purchased from Suzhou Kosida Electronic Materials Co., Ltd.

[0032] The following parts are by mass unless otherwise specified.

[0033] Example 1: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following steps: Step S1: Apply epoxy resin glue evenly on the surface of glass fiber cloth (the coating amount on one side is 150g / m 2 ), dried at 110°C for 20 min to obtain a glass fiber prepreg layer; Step S2: Apply epoxy resin glue evenly on the surface of the Cordura fiber woven cloth (the coating amount on one side is 150g / m 2 ), dried at 110°C for 20 min to obtain a puncture-resistant layer; Step S3: stacking the glass fiber prepreg layer, the puncture-resistant layer, and the glass fiber prepreg layer in sequence, and producing a laminated board by a hot pressing process (temperature of 160° C. and pressure of 10 MPa); Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate; The preparation method of epoxy resin glue is as follows: Step A: Under nitrogen protection, acrylic rosin is heated and melted, and magnolol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 120°C for 6 hours to obtain a hydroxyl-containing epoxy compound; the molar ratio of acrylic rosin to magnolol diglycidyl ether is 1:2, and the amount of triethylamine used is 1% of the total mass of acrylic rosin and magnolol diglycidyl ether; Step B: Under nitrogen protection, amino-terminated polydimethylsiloxane, terephthaloyl chloride and chloroform are uniformly mixed, triethylamine is added, and the mixture is reacted in an ice bath for 2 hours. A hydroxyl-containing epoxy compound is then added, and the mixture is reacted at room temperature for 3 hours. After extraction and drying, a polyamide-modified epoxy resin is obtained. The molar ratio of amino-terminated polydimethylsiloxane to terephthaloyl chloride is 1:2, and the amount of triethylamine used is 3% of the total mass of amino-terminated polydimethylsiloxane and terephthaloyl chloride. The molar ratio of hydroxyl-containing epoxy compound to terephthaloyl chloride is 1:0.5. Step C: 30 parts of polyamide-modified epoxy resin, 20 parts of phenoxy resin, 45 parts of bisphenol A epoxy resin, 10 parts of isocyanate-modified epoxy resin, 6 parts of dicyandiamide and 5 parts of epoxy accelerator are mixed uniformly to obtain epoxy resin glue.

[0034] Example 2: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following steps: Step S1: Apply epoxy resin glue evenly on the surface of glass fiber cloth (the coating amount on one side is 150g / m 2 ), dried at 115°C for 15 minutes to obtain a glass fiber prepreg layer; Step S2: Apply epoxy resin glue evenly on the surface of the Cordura fiber woven cloth (the coating amount on one side is 150g / m 2 ), dried at 115°C for 15 min to obtain a puncture-resistant layer; Step S3: stacking the glass fiber prepreg layer, the puncture-resistant layer, and the glass fiber prepreg layer in sequence, and producing a laminated board by a hot pressing process (temperature of 170° C. and pressure of 8 MPa); Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate; The preparation method of epoxy resin glue is as follows: Step A: Under nitrogen protection, acrylic rosin is heated and melted, and magnolol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 125°C for 7 hours to obtain a hydroxyl-containing epoxy compound; the molar ratio of acrylic rosin to magnolol diglycidyl ether is 1:2, and the amount of triethylamine used is 2% of the total mass of acrylic rosin and magnolol diglycidyl ether; Step B: Under nitrogen protection, amino-terminated polydimethylsiloxane, terephthaloyl chloride and chloroform are uniformly mixed, triethylamine is added, and the mixture is reacted in an ice bath for 3 hours. A hydroxyl-containing epoxy compound is then added, and the mixture is reacted at room temperature for 4 hours. After extraction and drying, a polyamide-modified epoxy resin is obtained. The molar ratio of amino-terminated polydimethylsiloxane to terephthaloyl chloride is 1:2.1, and the amount of triethylamine used is 4% of the total mass of amino-terminated polydimethylsiloxane and terephthaloyl chloride. The molar ratio of hydroxyl-containing epoxy compound to terephthaloyl chloride is 1:0.8. Step C: 40 parts of polyamide-modified epoxy resin, 30 parts of phenoxy resin, 55 parts of bisphenol A epoxy resin, 12 parts of isocyanate-modified epoxy resin, 10 parts of dicyandiamide and 8 parts of epoxy accelerator are mixed uniformly to obtain epoxy resin glue.

[0035] Example 3: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following steps: Step S1: Apply epoxy resin glue evenly on the surface of glass fiber cloth (the coating amount on one side is 150g / m 2 ), dried at 120°C for 10 min to obtain a glass fiber prepreg layer; Step S2: Apply epoxy resin glue evenly on the surface of the Cordura fiber woven cloth (the coating amount on one side is 150g / m 2 ), dried at 120°C for 20 min to obtain a puncture-resistant layer; Step S3: stacking the glass fiber prepreg layer, the puncture-resistant layer, and the glass fiber prepreg layer in sequence, and producing a laminated board by a hot pressing process (temperature of 180° C. and pressure of 5 MPa); Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate; The preparation method of epoxy resin glue is as follows: Step A: Under nitrogen protection, acrylic rosin is heated and melted, and magnolol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 130°C for 8 hours to obtain a hydroxyl-containing epoxy compound; the molar ratio of acrylic rosin to magnolol diglycidyl ether is 1:2, and the amount of triethylamine used is 3% of the total mass of acrylic rosin and magnolol diglycidyl ether; Step B: Under nitrogen protection, amino-terminated polydimethylsiloxane, terephthaloyl chloride and chloroform are uniformly mixed, triethylamine is added, and the mixture is reacted in an ice bath for 4 hours. A hydroxyl-containing epoxy compound is then added, and the mixture is reacted at room temperature for 5 hours. After extraction and drying, a polyamide-modified epoxy resin is obtained. The molar ratio of amino-terminated polydimethylsiloxane to terephthaloyl chloride is 1:2.2, and the amount of triethylamine used is 5% of the total mass of amino-terminated polydimethylsiloxane and terephthaloyl chloride. The molar ratio of hydroxyl-containing epoxy compound to terephthaloyl chloride is 1:1. Step C: 50 parts of polyamide-modified epoxy resin, 40 parts of phenoxy resin, 65 parts of bisphenol A epoxy resin, 15 parts of isocyanate-modified epoxy resin, 12 parts of dicyandiamide and 10 parts of epoxy accelerator are mixed uniformly to obtain epoxy resin glue.

[0036] Comparative Example 1: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following processes: The preparation method of epoxy resin glue is as follows: 40 parts of magnolol diglycidyl ether, 30 parts of phenoxy resin, 55 parts of bisphenol A epoxy resin, 12 parts of isocyanate modified epoxy resin, 10 parts of dicyandiamide and 8 parts of epoxy accelerator were mixed to obtain epoxy resin glue; Compared with Example 2, in Comparative Example 1, the polyamide-modified epoxy resin was replaced with magnolol diglycidyl ether of the same mass, and the other steps were the same as those in Example 2.

[0037] Comparative Example 2: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following processes: The preparation method of epoxy resin glue is as follows: Step A: Under nitrogen protection, acrylic rosin is heated and melted, and magnolol diglycidyl ether is added under the catalysis of triethylamine, and the reaction is carried out at 125°C for 7 hours to obtain a hydroxyl-containing epoxy compound; the molar ratio of acrylic rosin to magnolol diglycidyl ether is 1:2, and the amount of triethylamine used is 2% of the total mass of acrylic rosin and magnolol diglycidyl ether; Step B: 40 parts of a hydroxyl-containing epoxy compound, 30 parts of a phenoxy resin, 55 parts of a bisphenol A epoxy resin, 12 parts of an isocyanate-modified epoxy resin, 10 parts of dicyandiamide, and 8 parts of an epoxy accelerator are mixed to obtain an epoxy resin glue; Compared with Example 2, in Comparative Example 2, the polyamide-modified epoxy resin is replaced with a hydroxyl-containing epoxy compound of the same mass, and the other steps are the same as those in Example 2.

[0038] Comparative Example 3: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following processes: Step C: uniformly mixing 10 parts of a polyamide-modified epoxy resin, 30 parts of a phenoxy resin, 55 parts of a bisphenol A epoxy resin, 12 parts of an isocyanate-modified epoxy resin, 10 parts of dicyandiamide, and 8 parts of an epoxy accelerator to obtain an epoxy resin glue; Compared with Example 2, Comparative Example 3 reduces the amount of polyamide-modified epoxy resin added, and other steps are the same as Example 2.

[0039] Comparative Example 4: A method for preparing a mobile phone back cover laminate with improved puncture resistance, comprising the following processes: Step S1: Apply epoxy resin glue evenly on the surface of glass fiber cloth (the coating amount on one side is 150g / m 2 ), dried at 115°C for 15 minutes to obtain a glass fiber prepreg layer; Step S2: stacking a glass fiber prepreg layer, a glass fiber prepreg layer, and a glass fiber prepreg layer in sequence, and producing a laminated board by a hot pressing process (temperature of 170° C., pressure of 8 MPa); Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate; Compared with Example 2, in Comparative Example 4, the puncture-resistant layer is replaced with a glass fiber prepreg layer, and the other steps are the same as those in Example 2.

[0040] experiment: The laminates obtained in Examples 1-3 and Comparative Examples 1-4 were used to prepare samples, and their properties were tested and the test results were recorded: 1. Post-impact compression strength test: The sample is subjected to post-impact compression strength test in accordance with GB / T 21239-2022 standard; 2. Water absorption test: Make a 50mm×10mm sample, record the mass m1 before immersion, soak it in deionized water for 24 hours at a test temperature of 25°C, take it out and wipe off the surface moisture, record the mass m2 after immersion, and calculate the water absorption rate.

[0041] The test results are shown in Table 1.

[0042] Table 1 Compression strength after impact / MPa Water absorption / % Example 1 345 0.34 Example 2 353 0.30 Example 3 350 0.32 Comparative Example 1 315 0.53 Comparative Example 2 326 0.57 Comparative Example 3 331 0.45 Comparative Example 4 304 0.38 According to the data in the above table, we can clearly draw the following conclusions: Compared with Examples 1-3, the post-impact compressive strength and hydrophobicity of the products obtained in Comparative Examples 1 and 2 are both decreased, indicating that the polyamide-modified epoxy resin prepared by the present invention has better compatibility than magnolol diglycidyl ether due to the introduction of hydrophobic siloxane segments and polyamide structures, thereby effectively improving the hydrophobicity and mechanical properties of the material; compared with hydroxyl-containing epoxy compounds, the polyamide-modified epoxy resin prepared by the present invention has a better modification effect, thereby improving the interfacial compatibility between glass fiber cloth and Cordura woven cloth.

[0043] Compared with Examples 1-3, the post-impact compressive strength and hydrophobicity of the product obtained in Comparative Example 3 are both reduced. It can be seen that when the addition amount of polyamide-modified epoxy resin is reduced, the performance of the material will be reduced, indicating that the performance of the epoxy resin adhesive prepared by the present invention is affected by its component ratio. By selecting the component ratio within the said range, a material with better comprehensive performance can be prepared.

[0044] Compared with Examples 1-3, the post-impact compressive strength of the product obtained in Comparative Example 4 is decreased, which indicates that the Cordura fiber woven cloth has better impact resistance than the glass fiber cloth.

[0045] 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 embodied 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 illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A mobile phone back cover laminate with improved puncture resistance, characterized by: The mobile phone back cover laminate comprises, from the inside to the outside, a glass fiber prepreg layer, an anti-puncture layer, a glass fiber prepreg layer, a base layer, a pad printing layer, a packaging layer, and a protective layer. The anti-puncture layer and the glass fiber prepreg layer are cured together by epoxy resin glue.

2. The laminated plate for a mobile phone back cover with improved puncture resistance according to claim 1, characterized in that: The glass fiber prepreg layer is composed of glass fiber cloth impregnated with epoxy resin glue.

3. The mobile phone back cover laminate with improved puncture resistance according to claim 2, characterized in that: The preparation method of the epoxy resin glue is as follows: Step A: Under nitrogen protection, heat and melt acrylic rosin, add magnolol diglycidyl ether under the catalysis of triethylamine, and react at 120-130°C for 6-8 hours to obtain a hydroxyl-containing epoxy compound; Step B: Under nitrogen protection, amino-terminated polydimethylsiloxane, terephthaloyl chloride and chloroform are mixed uniformly, triethylamine is added, and the mixture is reacted in an ice bath for 2-4 hours. A hydroxyl-containing epoxy compound is then added, and the mixture is reacted at room temperature for 3-5 hours. After extraction and drying, a polyamide-modified epoxy resin is obtained; Step C: uniformly mixing polyamide-modified epoxy resin, phenoxy resin, bisphenol A epoxy resin, isocyanate-modified epoxy resin, dicyandiamide and epoxy accelerator to obtain epoxy resin glue.

4. The laminated plate for a mobile phone back cover with improved puncture resistance according to claim 3, characterized in that: The epoxy resin glue comprises the following components by weight: 30-50 parts of polyamide modified epoxy resin, 20-40 parts of phenoxy resin, 45-65 parts of bisphenol A epoxy resin, 10-15 parts of isocyanate modified epoxy resin, 6-12 parts of dicyandiamide, and 5-10 parts of epoxy accelerator.

5. The mobile phone back cover laminate with improved puncture resistance according to claim 3, characterized in that: In the step A, the molar ratio of rosin acrylate to magnolol diglycidyl ether is 1:

2.

6. The mobile phone back cover laminate with improved puncture resistance according to claim 5, characterized in that: The preparation method of described magnolol diglycidyl ether is as follows: Under nitrogen protection, magnolol, epichlorohydrin and benzyltriethylammonium chloride were mixed evenly, reacted at 80-90°C for 3-5 hours, cooled to 40-50°C, sodium hydroxide solution was added, and the reaction was continued for 1-3 hours. After filtration, washing and drying, magnolol diglycidyl ether was obtained.

7. The mobile phone back cover laminate with improved puncture resistance according to claim 1, characterized in that: The puncture-resistant layer is composed of cordura fiber woven cloth impregnated with epoxy resin glue.

8. The mobile phone back cover laminate with improved puncture resistance according to claim 1, characterized in that: The transfer printing layer is one of an epoxy resin adhesive layer, a polyurethane adhesive layer and an acrylic adhesive layer with texture.

9. The mobile phone back cover laminate with improved puncture resistance according to claim 1, characterized in that: The encapsulation layer is one of a transparent epoxy resin adhesive layer, a polyurethane adhesive layer, and an acrylic adhesive layer.

10. A method for preparing a mobile phone back cover laminate with improved puncture resistance according to any one of claims 1 to 9, characterized in that: The steps include: Step S1: evenly coating the epoxy resin glue on the surface of the glass fiber cloth, and drying at 110-120° C. for 10-20 minutes to obtain a glass fiber prepreg layer; Step S2: evenly coating the surface of the Cordura fiber woven fabric with epoxy resin glue, and drying at 110-120° C. for 10-20 minutes to obtain a puncture-resistant layer; Step S3: stacking the glass fiber prepreg layer, the puncture-resistant layer, and the glass fiber prepreg layer in sequence, and producing a laminate through a hot pressing process; Step S4: sequentially arranging a base layer, a pad printing layer, a packaging layer, and a protective layer on the laminate to obtain a mobile phone back cover laminate.