Transparent polycarbonate composite board with high flame retardance, high weather resistance and self-cleaning function and preparation method of transparent polycarbonate composite board

Abstract

The invention relates to a transparent polycarbonate composite board with high flame retardance, high weather resistance and a self-cleaning function and a preparation method of the transparent polycarbonate composite board. The transparent polycarbonate composite board comprises a UV layer, a bonding layer and a middle layer. The flame-retardant self-cleaning plastic not only has excellent transparency and mechanical properties, but also has excellent flame retardance, weather resistance and self-cleaning performance, and can keep good performance and appearance even if exposed to natural factors such as ultraviolet rays and rainwater for a long time in an outdoor environment. In addition, the method has the advantages of simplicity and convenience in operation, low cost and the like, is suitable for large-scale production and application, and can be widely applied to the fields of building curtain walls, automobile sunroofs, electronic display screens and the like.

Description

Technical Field

[0001] The invention belongs to the field of engineering plastics, and particularly relates to a transparent polycarbonate composite plate with high flame retardancy, high weather resistance and self-cleaning functions and a preparation method thereof. Background Art

[0002] As an important engineering plastic, polycarbonate is widely used in the fields of construction, automobile, electronics, etc. due to its excellent transparency, mechanical properties and thermal stability. However, the flame retardancy, weather resistance and self-cleaning properties of traditional polycarbonate solid boards still need to be improved. Especially in outdoor environments, polycarbonate solid boards are easily affected by natural factors such as ultraviolet rays and rain, resulting in performance degradation and appearance damage. In long-term outdoor applications, dust will be absorbed on the surface, affecting the appearance and optical properties, and the cleaning cost is high.

[0003] CN102173152A discloses a method for preparing an oil-proof self-cleaning polycarbonate film, wherein a fluorocarbon nano coating for forming a self-cleaning coating is applied to a highly transparent polycarbonate film or sheet by spin coating, and the coated polycarbonate film or sheet is heat-treated at about 100°C for about 60 minutes. The coating prepared by this method is easily damaged due to the insufficient bonding force between the fluorocarbon layer and the polycarbonate, and the coating has poor wear resistance, and is particularly unsuitable for harsh outdoor environments.

[0004] CN107189656B discloses a method for improving the wear resistance of a self-cleaning coating, that is, by increasing a polycarbonate glue layer and an intermediate layer, the wear resistance is improved, and the polycarbonate is corroded by acetone to form a micron-level roughness. However, this method uses solvents such as tetrahydrofuran, benzene or toluene that have a destructive effect on polycarbonate, which easily leads to embrittlement of the substrate and reduces weather resistance. At the same time, acetone is used to corrode the polycarbonate on the surface, which easily induces a crystallization effect of the polycarbonate, further embrittles the polycarbonate material, and causes a phenomenon of whitish fog and opacity. The resulting product loses the good transparency and impact resistance of polycarbonate. It does not meet the long-term outdoor use requirements for high light transmittance, weather resistance and structural strength.

[0005] The existing known polycarbonate self-cleaning technology has a complex preparation process and is immature, and cannot meet the strict requirements of polycarbonate products for outdoor applications on high light transmittance, high weather resistance, high wear resistance and self-cleaning. Therefore, it is of great significance and application value to develop a transparent polycarbonate composite board with high flame retardancy, high weather resistance and self-cleaning functions. 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. The composite board not only has excellent transparency and mechanical properties, but also has excellent flame retardancy, weather resistance and self-cleaning properties.

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

[0008] Preferably, the ultraviolet absorber A is one or more of benzophenone, benzotriazole, substituted acrylonitrile, triazine, etc.; the ultraviolet absorber B is one or more of benzophenone, benzotriazole, substituted acrylonitrile, triazine, etc.; the ultraviolet absorber A and the ultraviolet absorber B are different.

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

[0010] Preferably, the weight average molecular weights of the modified polycarbonate A, the modified polycarbonate B and the modified polycarbonate C are all 25000 - 40000 g / mol.

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

[0012] Preferably, the catalyst is triethylamine.

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

[0014] The UV layer has excellent oil and water resistance and can achieve a self-cleaning effect. It also has excellent weather resistance and light transmittance. It can effectively absorb and shield ultraviolet rays and protect the underlying materials from being damaged by ultraviolet rays.

[0015] The bonding layer can be bonded to the UV layer and the intermediate layer at the same time, and has good weather resistance and light transmittance.

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

[0017] Furthermore, the components of the UV layer, the bonding layer and the intermediate layer also include 0.1-1% of toner, carbon nanotubes, nano silicon dioxide, a release agent and an antioxidant.

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

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

[0020] Furthermore, the composite board also includes a surface layer with a bionic texture structure. The bionic texture structure combined with the self-cleaning performance of the UV layer material can make water droplets roll off the board surface, thereby realizing the self-cleaning function.

[0021] Preferably, the bionic texture structure is obtained by online transfer printing with a precision roller, and the roughness is 0.1 μm to 10 μm. The self-cleaning function and long-term aesthetics of the polycarbonate composite plate are improved by the precision roller transfer printing process.

[0022] The present invention also provides a method for preparing a transparent polycarbonate composite plate 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 according to the proportions to form three layers of different melts; (2) Introducing three layers of different melts into the mold through different flow channels for in-mold compounding to obtain a composite plate; (3) Forming a bionic texture structure on the surface of the composite board through precision roller online transfer technology; (4) Cooling and shaping, demolding, and obtaining a transparent polycarbonate solid plate with high flame retardancy, high weather resistance, high light transmittance, and self-cleaning functions.

[0023] The present invention also provides a transparent polycarbonate composite board with high flame retardancy, high weather resistance and self-cleaning functions for use in building curtain walls, automobile skylights and electronic display screens.

[0024] Beneficial Effects (1) The UV layer of the present invention adopts modified polycarbonate A, which has a high fluorine content, and the molecular chain end group of the surface layer contains a bistrifluoromethyl functional group, which is used to enhance the hydrophobicity of the composite board and reduce the surface friction coefficient; the middle layer adopts modified polycarbonate B, which is mainly bromine-containing copolymer PC, to improve the fireproof performance of the entire board; the bonding layer adopts modified polycarbonate C, which contains both the functional groups of the UV layer and the functional groups of the middle layer, and can enhance the bonding force between the UV layer and the middle layer.

[0025] (2) The present invention not only has excellent transparency and mechanical properties, but also has excellent flame retardancy, weather resistance and self-cleaning properties. Even when exposed to natural factors such as ultraviolet rays and rain for a long time in outdoor environments, it can maintain good performance and appearance. In addition, the present invention has the advantages of simple operation and low cost, and is suitable for large-scale production and application. It can be widely used in the fields of building curtain walls, automobile sunroofs, electronic display screens, etc. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0027] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

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

[0029] After the modified polycarbonate A was desolventized, washed, filtered and dried, the GPC molecular weight was measured, and the weight average molecular weight was 32000 g / mol, the number average molecular weight was 19000 g / mol, the molecular weight distribution (weight average molecular weight / number average molecular weight) PD=1.68, and the DSC test glass transition temperature Tg=185°C.

[0030] Modified polycarbonate B: prepared by interfacial phosgene method using 3,5-bis(trifluoromethyl)phenol as end-capping agent and bisphenol AF, bisphenol A and isosorbide with a molar ratio of 1:5:1 as comonomers: ① Dissolve bisphenol AF, bisphenol A and isosorbide in a sodium hydroxide aqueous solution at a molar ratio of 1:5:1, adjust the pH value to a range of 9 to 12, and convert all monomers into sodium phenol salts; introduce phosgene for interfacial prepolymerization to prepare a polycarbonate oligomer solution; ② Add 3,5-bis(trifluoromethyl)phenolate solution and catalyst triethylamine (added at a monomer molar ratio of 3% and 0.3%, respectively) to the polycarbonate oligomer solution to carry out polycondensation and end-capping reaction (react at 35°C for 20 minutes) to prepare a modified polycarbonate B solution with a residual monomer content of <50ppm.

[0031] After the modified polycarbonate B was desolventized, washed, filtered and dried, the GPC molecular weight was determined, with a weight average molecular weight of 31,000 g / mol, a number average molecular weight of 18,500 g / mol, a molecular weight distribution (weight average molecular weight / number average molecular weight) of PD=1.675, and a DSC glass transition temperature of Tg=155°C.

[0032] Modified polycarbonate C: prepared by interfacial phosgene method using phenol as 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 a sodium hydroxide aqueous solution at a molar ratio of 3:1:1, adjust the pH value to a range of 10-13, and convert all monomers into sodium phenol salts; introduce phosgene for interfacial prepolymerization to prepare a polycarbonate oligomer solution; ② Add 3,5-bis(trifluoromethyl)phenolate solution and catalyst triethylamine (added at a monomer molar ratio of 3% and 0.3%, respectively) to the polycarbonate oligomer solution to carry out polycondensation and end-capping reaction (react at 35°C for 20 minutes) to prepare a modified polycarbonate C solution with a residual monomer content of <50ppm.

[0033] After the modified polycarbonate B was desolventized, washed, filtered and dried, the GPC molecular weight was measured, and 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 DSC test glass transition temperature Tg=175°C.

[0034] Ultraviolet absorber A: UV531.

[0035] Ultraviolet absorber B: UV1557.

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

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

[0038] The method for preparing the transparent polycarbonate composite plate comprises 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 to form three layers of different melts; (2) Introducing three layers of different melts into the mold through different flow channels for in-mold compounding to obtain a composite plate; (3) Forming a bionic texture structure on the surface of the composite board through precision roller online transfer technology; (4) Cooling and shaping, demolding, and obtaining a transparent polycarbonate solid plate with high flame retardancy, high weather resistance, high light transmittance, and self-cleaning functions.

[0039] Table 1 Example formulation Table 2 Comparative Example Formula Table 3 Performance test results

Claims

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

2. The transparent polycarbonate composite panel 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 the ultraviolet absorber B are different.

3. The transparent polycarbonate composite panel according to claim 1, characterized in that: The neutral hindered amine light stabilizer is one or more of an anionic hindered amine light stabilizer, a cationic hindered amine light stabilizer and a nonionic hindered amine light stabilizer.

4. The transparent polycarbonate composite panel according to claim 1, characterized in that: The weight average molecular weight of the modified polycarbonate A, modified polycarbonate B and modified polycarbonate C are all 25000-40000 g / mol.

5. The transparent polycarbonate composite panel according to claim 1, characterized in that: The components of the UV layer, the bonding layer and the intermediate layer also include 0.1-1% of toner, carbon nanotubes, nano silicon dioxide, a release agent and an antioxidant.

6. The transparent polycarbonate composite panel according to claim 1, characterized in that: The composite board also includes a surface layer having a bionic texture structure.

7. The transparent polycarbonate composite panel according to claim 6, characterized in that: The bionic texture structure is obtained by online transfer through a precision roller, and has a roughness of 0.1 μm to 10 μm.

8. A method for preparing a transparent polycarbonate composite plate with high flame retardancy, high weather resistance and self-cleaning function, comprising the following steps: (1) Mixing, melting and extruding the components of the UV layer, the bonding layer and the intermediate layer in the proportions as described in claim 1 to form three different melts; (2) Introducing three layers of different melts into the mold through different flow channels for in-mold compounding to obtain a composite plate; (3) Forming a bionic texture structure on the surface of the composite board through precision roller online transfer technology; (4) Cooling and shaping, demolding, and obtaining a transparent polycarbonate solid plate with high flame retardancy, high weather resistance, high light transmittance, and self-cleaning functions.

9. Use of the transparent polycarbonate composite board with high flame retardancy, high weather resistance and self-cleaning function as claimed in claim 1 in building curtain walls, automobile skylights and electronic display screens.

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