A transparent polycarbonate composite board with high flame retardance, high weather resistance and self-cleaning function and a preparation method thereof

Abstract

The present application relates to a kind of transparent polycarbonate composite board with high flame retardant, high weather resistance, self-cleaning function and preparation method thereof, the transparent polycarbonate composite board includes UV layer, bonding layer and intermediate layer.The present application not only has excellent transparency and mechanical properties, but also has excellent flame retardancy, weather resistance and self-cleaning performance, even in outdoor environment, long-term exposure to ultraviolet light, rain and other natural factors, can maintain good performance and appearance.In addition, the present application also has the advantages of simple operation, low cost and the like, suitable for large-scale production and application, can be widely used in building curtain wall, automobile sunroof, electronic display screen and other fields.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics, and specifically relates to a transparent polycarbonate composite board with high flame retardancy, high weather resistance and self-cleaning function and its preparation method. Background Technology

[0002] Polycarbonate, as an important engineering plastic, is widely used in construction, automotive, and electronics industries due to its excellent transparency, mechanical properties, and thermal stability. However, traditional solid polycarbonate sheets still need improvement in terms of flame retardancy, weather resistance, and self-cleaning properties. Especially in outdoor environments, solid polycarbonate sheets are susceptible to the effects of ultraviolet radiation, rain, and other natural factors, leading to performance degradation and aesthetic damage. Long-term outdoor use also results in dust accumulation on the surface, affecting appearance and optical properties, and cleaning costs are high.

[0003] CN102173152A discloses a method for preparing an oil-resistant, self-cleaning polycarbonate film. The method involves spin-coating a fluorocarbon nano-coating for forming a self-cleaning film onto a highly transparent polycarbonate film or sheet, followed by heat treatment of the coated polycarbonate film or sheet at approximately 100°C for about 60 minutes. However, the coating prepared by this method suffers from insufficient adhesion between the fluorocarbon layer and the polycarbonate, leading to easy damage and poor abrasion resistance, making it particularly unsuitable for harsh outdoor environments.

[0004] CN107189656B discloses a method for improving the wear resistance of self-cleaning coatings, which involves adding a polycarbonate adhesive layer and an intermediate layer to enhance wear resistance, and using acetone to corrode the polycarbonate to create a micron-level roughness. However, this method uses solvents such as tetrahydrofuran, benzene, or toluene, which have a destructive effect on polycarbonate, easily leading to substrate embrittlement and reduced weather resistance. Furthermore, the use of acetone to corrode the polycarbonate surface can easily induce crystallization, further embrittlement of the polycarbonate material, and the appearance of whitening, haziness, and opacity. The resulting product loses the good transparency and impact resistance of polycarbonate, failing to meet the long-term outdoor requirements for high light transmittance, weather resistance, and structural strength.

[0005] Existing technologies for achieving self-cleaning properties in polycarbonate are complex and immature, failing to meet the stringent requirements of high light transmittance, high weather resistance, high abrasion resistance, and self-cleaning for outdoor polycarbonate products. Therefore, developing a transparent polycarbonate composite board with high flame retardancy, high weather resistance, and self-cleaning properties is of significant importance and application value. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a transparent polycarbonate composite board with high flame retardancy, high weather resistance and self-cleaning function and its preparation method. The composite board not only has excellent transparency and mechanical properties, but also has excellent flame retardancy, weather resistance and self-cleaning properties.

[0007] This invention provides a transparent polycarbonate composite board with high flame retardancy, high weather resistance, and self-cleaning function. The transparent polycarbonate composite board includes a UV layer, a bonding layer, and an intermediate layer. The UV layer comprises the following components: modified polycarbonate A, and 0.5% to 5% of UV absorber A, 0.5% to 5.5% of UV absorber B and 0.3% to 2% of neutral hindered amine light stabilizer, accounting for 0.5% to 5% of the total mass of modified polycarbonate A. The bonding layer comprises the following components: modified polycarbonate B, and 0.1% to 1% of ultraviolet absorber A, 0.1% to 1% of ultraviolet absorber B and 0.1% to 1% of neutral hindered amine light stabilizer, accounting for 0.1% to 1% of the total mass of modified polycarbonate B. The intermediate layer comprises the following components: modified polycarbonate C, and 0.1% to 1% of ultraviolet absorber A, 0.1% to 1% of ultraviolet absorber B and 0.1% to 1% of neutral hindered amine light stabilizer, accounting for 0.1% to 1% of the total mass of modified polycarbonate C. The modified polycarbonate A was prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as the end-capping agent and bisphenol AF, bisphenol A and isosorbide in a molar ratio of 1:2:1 as comonomers. The modified polycarbonate B was prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as the end-capping agent and bisphenol AF, bisphenol A and isosorbide as comonomers in a molar ratio of 1:5:1. The modified polycarbonate C was prepared by interfacial phosgene method using phenol as the end-capping agent and tetrabromobisphenol A, bisphenol A and isosorbide in a molar ratio of 3:1:1 as comonomers.

[0008] Preferably, the ultraviolet absorber A is one or more of benzophenone, benzotriazole, substituted acrylonitrile, and triazine; the ultraviolet absorber B is one or more of benzophenone, benzotriazole, substituted acrylonitrile, and triazine; and the ultraviolet absorber A and ultraviolet absorber B are not the same.

[0009] Preferably, the neutral hindered amine light stabilizer is one or more of anionic hindered amine light stabilizers, cationic hindered amine light stabilizers, and nonionic hindered amine light stabilizers.

[0010] Preferably, the weight-average molecular weight of the modified polycarbonate A, modified polycarbonate B, and modified polycarbonate C is 25,000-40,000 g / mol.

[0011] Preferably, 0.05% to 0.3% of a catalyst is added during the preparation process of the interfacial phosgene method.

[0012] Preferably, the catalyst is triethylamine.

[0013] Preferably, the thickness of the UV layer is 10μm to 1000μm; the thickness of the bonding layer is 50μm to 2000μm; and the thickness of the intermediate layer is 1mm to 30mm.

[0014] The UV layer has excellent oil and water resistance, achieves self-cleaning effect, and also has excellent weather resistance and light transmittance. It can effectively absorb and shield ultraviolet rays, protecting the underlying material from UV damage.

[0015] The bonding layer can bond with both the UV layer and the intermediate layer at the same time, and also has good weather resistance and light transmittance.

[0016] The intermediate layer has excellent flame retardant properties, which can effectively improve the flame retardant rating of the entire composite board.

[0017] Furthermore, the UV layer, bonding layer, and intermediate layer also include 0.1-1% of colorant, carbon nanotubes, nano-silica, release agent, and antioxidant.

[0018] Preferably, the release agent is pentaerythritol tetrastearate, glyceryl monostearate, glyceryl tristearate, or any combination thereof.

[0019] Preferably, the antioxidant is a hindered phenolic antioxidant, a phosphite antioxidant, a thioester antioxidant, or any combination thereof.

[0020] Furthermore, the composite board also includes a surface layer with a biomimetic texture structure. The biomimetic texture structure, combined with the self-cleaning properties of the UV layer material, allows water droplets to roll off the surface, thus achieving a self-cleaning function.

[0021] Preferably, the biomimetic texture structure is obtained by online transfer using precision rollers, with a roughness of 0.1μm to 10μm. This precision roller transfer process improves the self-cleaning function and long-term aesthetics of the polycarbonate composite board.

[0022] This invention also provides a method for preparing a transparent polycarbonate composite board with high flame retardancy, high weather resistance, and self-cleaning functions, comprising the following steps: (1) The components of the UV layer, the bonding layer and the intermediate layer are mixed, melted and extruded in proportion to form three different melts; (2) Three different melts are introduced into the mold through different flow channels to perform in-mold composite to obtain a composite plate; (3) A biomimetic texture structure is formed on the surface of the composite board by means of precision pressure roller online transfer technology; (4) Cool and shape, demold, and obtain a transparent polycarbonate solid board with high flame retardancy, high weather resistance, high light transmittance and self-cleaning function.

[0023] This invention also provides an application of a transparent polycarbonate composite panel with high flame retardancy, high weather resistance, and self-cleaning properties in building curtain walls, car sunroofs, and electronic displays.

[0024] Beneficial effects (1) The UV layer in this invention uses modified polycarbonate A, which has a high fluorine content and the surface layer molecular chain end group contains bis(trifluoromethyl) functional groups, which are used to enhance the hydrophobicity of the composite board and reduce the surface friction coefficient; the intermediate layer uses modified polycarbonate B, which is mainly bromine-containing copolymer PC, to improve the fire resistance of the entire board; the bonding layer uses modified polycarbonate C, which contains functional groups of both the UV layer and the intermediate layer, which can improve the bonding force between the UV layer and the intermediate layer.

[0025] (2) This invention not only possesses excellent transparency and mechanical properties, but also outstanding flame retardancy, weather resistance, and self-cleaning properties. Even when exposed to natural factors such as ultraviolet radiation and rain in outdoor environments for extended periods, it can maintain good performance and appearance. Furthermore, this invention has the advantages of simple operation and low cost, making it suitable for large-scale production and application. It can be widely used in fields such as building curtain walls, car sunroofs, and electronic displays. Detailed Implementation

[0026] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0027] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0028] The components used in the examples and comparative examples are as follows: Modified polycarbonate A: prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as end-capping agent and bisphenol AF, bisphenol A and isosorbide in a molar ratio of 1:2:1 as comonomers. ① Dissolve bisphenol AF, bisphenol A and isosorbide in an aqueous sodium hydroxide solution in a molar ratio of 1:2:1, adjust the pH value to the range of 9-12, so that all monomers are converted into sodium phenolate form; introduce phosgene to carry out interfacial prepolymerization to prepare polycarbonate oligomer solution. ② Add 3,5-bis(trifluoromethyl)phenol salt solution and triethylamine catalyst (added at monomer molar ratios of 3% and 0.3%, respectively) to polycarbonate oligomer solution for polycondensation and end-capping reaction (continuous reaction at 35℃ for 20 min) to prepare modified polycarbonate A solution with residual monomer content <50ppm.

[0029] After solvent removal, washing, filtration, and drying, modified polycarbonate A was subjected to GPC molecular weight determination. The weight-average molecular weight was 32,000 g / mol, the number-average molecular weight was 19,000 g / mol, the molecular weight distribution (weight-average molecular weight / number-average molecular weight) PD=1.68, and the glass transition temperature Tg was 185℃ according to DSC test.

[0030] Modified polycarbonate B: Prepared via interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as the end-capping agent and bisphenol AF, bisphenol A, and isosorbide as comonomers in a molar ratio of 1:5:1. ① Dissolve bisphenol AF, bisphenol A and isosorbide in an aqueous sodium hydroxide solution in a molar ratio of 1:5:1, adjust the pH value to the range of 9-12, so that all monomers are converted into sodium phenolate form; introduce phosgene to carry out interfacial prepolymerization to prepare polycarbonate oligomer solution. ② Add 3,5-bis(trifluoromethyl)phenol salt solution and triethylamine catalyst (added at monomer molar ratios of 3% and 0.3%, respectively) to polycarbonate oligomer solution for polycondensation and end-capping reaction (continuous reaction at 35℃ for 20 min) to prepare modified polycarbonate B solution with residual monomer content <50ppm.

[0031] After solvent removal, washing, filtration, and drying, modified polycarbonate B was subjected to GPC molecular weight determination. The weight-average molecular weight was 31,000 g / mol, the number-average molecular weight was 18,500 g / mol, the molecular weight distribution (weight-average molecular weight / number-average molecular weight) PD=1.675, and the glass transition temperature Tg was 155℃ according to DSC test.

[0032] Modified polycarbonate C: prepared by interfacial phosgene method using phenol as the end-capping agent and tetrabromobisphenol A, bisphenol A and isosorbide in a molar ratio of 3:1:1 as comonomers. ① Dissolve tetrabromobisphenol A, bisphenol A and isosorbide in an aqueous sodium hydroxide solution in a molar ratio of 3:1:1, adjust the pH value to the range of 10-13, so that all monomers are converted into sodium phenolate form; introduce phosgene to carry out interfacial prepolymerization to prepare polycarbonate oligomer solution. ② Add 3,5-bis(trifluoromethyl)phenol salt solution and triethylamine catalyst (added at monomer molar ratios of 3% and 0.3%, respectively) to polycarbonate oligomer solution for polycondensation and end-capping reaction (continuous reaction at 35℃ for 20 min) to prepare modified polycarbonate C solution with residual monomer content <50ppm.

[0033] After solvent removal, washing, filtration, and drying, modified polycarbonate B was subjected to GPC molecular weight determination. The weight-average molecular weight was 33000 g / mol, the number-average molecular weight was 21500 g / mol, the molecular weight distribution (weight-average molecular weight / number-average molecular weight) PD=1.53, and the glass transition temperature Tg was 175℃ according to DSC test.

[0034] Ultraviolet absorber A: UV531.

[0035] Ultraviolet absorber B: UV1557.

[0036] Neutral hindered amine light stabilizer: Chiguard® 202.

[0037] Other additives: Inorganic ultramarine blue powder, carbon nanotubes, nano-silica, release agent and antioxidant in a mass ratio of 1:1:1:1:1.

[0038] The method for preparing the transparent polycarbonate composite board includes the following steps: (1) The components of the UV layer, the bonding layer and the intermediate layer are mixed, melted and extruded in proportion to form three different melts; (2) Three different melts are introduced into the mold through different flow channels to perform in-mold composite to obtain a composite plate; (3) A biomimetic texture structure is formed on the surface of the composite board by means of precision pressure roller online transfer technology; (4) Cool and shape, demold, and obtain a transparent polycarbonate solid board with high flame retardancy, high weather resistance, high light transmittance and self-cleaning function.

[0039] Table 1 Formulation of Examples Table 2 Comparative Formulations Table 3 Performance Test Results

Claims

1. A transparent polycarbonate composite board with high flame retardancy, high weather resistance, and self-cleaning properties, characterized in that: The transparent polycarbonate composite board includes a UV layer, a bonding layer, and an intermediate layer; The UV layer comprises the following components: modified polycarbonate A, and 0.5% to 5% of UV absorber A, 0.5% to 5.5% of UV absorber B and 0.3% to 2% of neutral hindered amine light stabilizer, accounting for 0.5% to 5% of the total mass of modified polycarbonate A. The bonding layer comprises the following components: modified polycarbonate B, and 0.1% to 1% of ultraviolet absorber A, 0.1% to 1% of ultraviolet absorber B and 0.1% to 1% of neutral hindered amine light stabilizer, accounting for 0.1% to 1% of the total mass of modified polycarbonate B. The intermediate layer comprises the following components: modified polycarbonate C, and 0.1% to 1% of ultraviolet absorber A, 0.1% to 1% of ultraviolet absorber B and 0.1% to 1% of neutral hindered amine light stabilizer, accounting for 0.1% to 1% of the total mass of modified polycarbonate C. The modified polycarbonate A was prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as the end-capping agent and bisphenol AF, bisphenol A and isosorbide in a molar ratio of 1:2:1 as comonomers. The modified polycarbonate B was prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as the end-capping agent and bisphenol AF, bisphenol A and isosorbide as comonomers in a molar ratio of 1:5:

1. The modified polycarbonate C was prepared by interfacial phosgene method using phenol as the end-capping agent and tetrabromobisphenol A, bisphenol A and isosorbide in a molar ratio of 3:1:1 as comonomers.

2. The transparent polycarbonate composite board according to claim 1, characterized in that: The ultraviolet absorber A is one or more of benzophenone, benzotriazole, substituted acrylonitrile, and triazine; the ultraviolet absorber B is one or more of benzophenone, benzotriazole, substituted acrylonitrile, and triazine; the ultraviolet absorber A and ultraviolet absorber B are not the same.

3. The transparent polycarbonate composite board according to claim 1, characterized in that: The weight-average molecular weights of the modified polycarbonate A, modified polycarbonate B, and modified polycarbonate C are all 25,000-40,000 g / mol.

4. The transparent polycarbonate composite board according to claim 1, characterized in that: The components of the UV layer, bonding layer and intermediate layer also include 0.1-1% pigment, carbon nanotubes, nano-silica, release agent and antioxidant.

5. The transparent polycarbonate composite board according to claim 1, characterized in that: The composite board also includes a surface layer with a biomimetic texture structure.

6. The transparent polycarbonate composite board according to claim 5, characterized in that: The biomimetic texture structure is obtained by online transfer using precision pressure rollers, with a roughness of 0.1μm~10μm.

7. A method for preparing a transparent polycarbonate composite board with high flame retardancy, high weather resistance, and self-cleaning properties, comprising the following steps: (1) The components of the UV layer, the bonding layer and the intermediate layer are mixed, melted and extruded according to the proportions of claim 1 to form three different melts; (2) Three different melts are introduced into the mold through different flow channels to perform in-mold composite to obtain a composite plate; (3) A biomimetic texture structure is formed on the surface of the composite board by means of precision pressure roller online transfer technology; (4) Cool and shape, demold, and obtain a transparent polycarbonate solid board with high flame retardancy, high weather resistance, high light transmittance and self-cleaning function.

8. The application of a transparent polycarbonate composite panel with high flame retardancy, high weather resistance and self-cleaning function as described in claim 1 in building curtain walls, car sunroofs and electronic displays.

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