An anti-aging CPVC material for aluminum-plastic composite decorative strips and its preparation method

Abstract

This invention discloses an anti-aging CPVC material for aluminum-plastic composite decorative strips and its preparation method, relating to the field of polymer material modification. The anti-aging CPVC material for aluminum-plastic composite decorative strips comprises the following raw materials in parts by weight: 50-60 parts of modified chlorinated polyvinyl chloride, 20-40 parts of ABS resin, 8-10 parts of polyvinyl chloride resin, 4-6 parts of heat stabilizer, 2-4 parts of lubricant, and 5-15 parts of calcium carbonate. The modified chlorinated polyvinyl chloride is prepared by a click reaction between chlorinated polyvinyl chloride grafted with an anti-UV intermediate and an antioxidant intermediate. The anti-UV intermediate is prepared by a nucleophilic substitution reaction between 1-(allyloxy)-2-bromobenzene and sodium azide to obtain an anti-UV precursor, followed by a Claisen rearrangement of the anti-UV precursor. The antioxidant intermediate is prepared by a nucleophilic substitution reaction between 4-ethynylbenzene-1,2-diol and phosphorus oxychloride to obtain a flame-retardant monomer, followed by a nucleophilic substitution reaction between the flame-retardant monomer and 2,4-dihydroxybenzophenone.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, specifically to an anti-aging CPVC material for aluminum-plastic composite decorative strips and its preparation method. Background Technology

[0002] Chlorinated polyvinyl chloride (CPVC) is widely used as the core material for aluminum-plastic composite decorative strips in building curtain walls, door and window decoration, and interior decoration due to its excellent corrosion resistance and easy processing. However, the unsaturated bonds and chlorine atoms in the CPVC molecular structure make it prone to photodegradation under ultraviolet radiation, resulting in yellowing, embrittlement, and powdering of the material, which greatly shortens the service life of the aluminum-plastic decorative strips.

[0003] Currently, most CPVC core materials used in aluminum-plastic composite decorative strips employ physical blending with functional additives such as anti-aging agents to enhance their anti-aging performance. However, small-molecule anti-aging agents have poor compatibility with the CPVC matrix and are prone to migration and precipitation during long-term use or high-temperature processing, failing to provide long-term protection. This leads to aging phenomena such as yellowing, embrittlement, and powdering of the CPVC core material, affecting the appearance and service life of the decorative strip. Furthermore, the migration of small-molecule additives can reduce the adhesion between the CPVC core material and the aluminum alloy panel. Since CPVC itself is a non-polar material, it has poor interfacial compatibility with adhesive films such as ethylene-vinyl acetate copolymers on the aluminum alloy panel surface, easily causing problems such as interlayer delamination, blistering, and edge curling. This severely affects the overall structural stability of the aluminum-plastic composite decorative strip, making it unsuitable for free splicing of various sizes and long-term outdoor use.

[0004] Although CPVC itself possesses good flame-retardant properties, further flame-retardant and smoke-suppressing modifications are still necessary. The core reason is that while CPVC is not easily ignited and spreads during combustion, it releases a large amount of toxic and harmful fumes, which can easily cause asphyxiation and secondary corrosion damage. Furthermore, the intrinsic flame retardancy of CPVC only initially inhibits the spread of combustion and cannot form a stable and dense char layer. During combustion, dripping is likely to occur, potentially igniting surrounding combustibles and posing a safety hazard. Existing CPVC flame-retardant modification schemes mostly focus on adding inorganic flame retardants or blending with chlorinated polyethylene, neoprene rubber, etc., but they still fall short in balancing smoke density reduction and improved processing fluidity. Moreover, the flame-retardant performance of existing modified CPVC materials largely relies on a single flame-retardant system, resulting in low flame-retardant efficiency. Large amounts of flame-retardant additives are required to meet usage requirements, which exacerbates additive migration problems and affects the material's processing performance and anti-aging effects.

[0005] Therefore, the present invention will provide a method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips. Summary of the Invention

[0006] To address the shortcomings mentioned in the background art, the present invention aims to provide an anti-aging CPVC material for aluminum-plastic composite decorative strips and its preparation method. The prepared CPVC material has excellent anti-ultraviolet aging properties, flame retardant properties, and interlayer bonding properties.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips, characterized in that it comprises the following raw materials in parts by weight: 50-60 parts of modified chlorinated polyvinyl chloride, 20-40 parts of ABS resin, 8-10 parts of polyvinyl chloride resin, 4-6 parts of heat stabilizer, 2-4 parts of lubricant, and 5-15 parts of calcium carbonate. The modified chlorinated polyvinyl chloride is prepared by a click reaction between chlorinated polyvinyl chloride grafted with an anti-UV intermediate and an antioxidant intermediate; wherein, the anti-UV intermediate is prepared by a nucleophilic substitution reaction between 1-(allyloxy)-2-bromobenzene and sodium azide to obtain an anti-UV precursor, and then by a Claisen rearrangement of the anti-UV precursor; the antioxidant intermediate is prepared by a nucleophilic substitution reaction between 4-ethynylbenzene-1,2-diol and phosphorus oxychloride to obtain a flame retardant monomer, and then by a nucleophilic substitution reaction between the flame retardant monomer and 2,4-dihydroxybenzophenone.

[0008] More preferably, the ABS resin contains 19-22% acrylonitrile, 20-25% butadiene, and 50-57% styrene.

[0009] More preferably, the heat stabilizer is methyltin mercaptan or octyltin mercaptan.

[0010] More preferably, the lubricant is polyethylene wax or oxidized polyethylene wax.

[0011] More preferably, the preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take chlorinated polyvinyl chloride (PVC) into a reactor, add a 5-15% sodium hydroxide aqueous solution, heat to 70-80℃, stir and react for 1-3 hours to remove hydrogen chloride. Then add the treated PVC, UV-resistant intermediate, benzoyl peroxide, and cyclohexanone into the reactor, heat to 80-90℃, stir and react for 2-4 hours. After the reaction is complete, precipitate the product with ethanol, then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. The second step involves placing UV-resistant chlorinated polyvinyl chloride, an antioxidant intermediate, and cuprous bromide into a reactor. Tetrahydrofuran is added under a nitrogen atmosphere. The oxygen in the reaction solution is removed by three cycles of freezing, vacuuming, melting, and nitrogen purging. Pentamethyldiethylenetriamine is then added, and the mixture is stirred at room temperature for 10-12 hours. After the reaction is complete, the mixture is poured into a methanol solution for precipitation, and the solid is filtered off. The resulting solid is then washed and dried to obtain modified chlorinated polyvinyl chloride.

[0012] More preferably, in the first step, the mass ratio of chlorinated polyvinyl chloride, sodium hydroxide aqueous solution, UV-resistant intermediate, and benzoyl peroxide is 20-25:30-40:3-4:0.5-0.6.

[0013] More preferably, in the second step, the mass ratio of UV-resistant chlorinated polyvinyl chloride, antioxidant intermediate, cuprous bromide, and pentamethyldiethylenetriamine is 18-20:2-3:0.5-0.8:0.3-0.5.

[0014] More preferably, the method for preparing the UV-resistant intermediate includes the following steps: A. Take 1-(allyloxy)-2-bromobenzene, sodium azide, cuprous iodide, N,N'-dimethylethylenediamine, and potassium carbonate in a reactor. Add N,N-dimethylformamide under a nitrogen atmosphere, heat to 80-90℃, and stir the reaction for 10-14 hours. After the reaction is completed, filter to remove the filter residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take the UV-resistant precursor into the reactor, add nitrobenzene under a nitrogen atmosphere, and react at 200-210℃ for 4-5 hours. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate.

[0015] More preferably, in step A, the mass ratio of 1-(allyloxy)-2-bromobenzene, sodium azide, cuprous iodide, N,N'-dimethylethylenediamine, and potassium carbonate is 4-6:1.8-2.7:0.2-0.28:0.17-0.26:5-7.8.

[0016] More preferably, the method for preparing the antioxidant intermediate includes the following steps: S1. Take 4-ethynylbenzene-1,2-diol, phosphorus oxychloride, and acid-binding agent into a reactor, add chloroform, heat to 55-65℃, stir the reaction for 2-3 hours, filter to remove solid after the reaction, remove solvent by rotary evaporation of filtrate, and then elute by column chromatography to obtain flame retardant monomer. S2. Take 2,4-dihydroxybenzophenone and potassium carbonate in a reactor, add cyclohexanone, heat to 30-40℃, then add flame retardant monomer dropwise. After the addition is complete, heat to 140-160℃ and stir the reaction for 5-7 hours. After the reaction is complete, filter to remove the solid, and remove the solvent by rotary evaporation of the filtrate to obtain the antioxidant intermediate.

[0017] More preferably, the acid-binding agent in step S1 is pyridine or triethylamine.

[0018] More preferably, in step S1, the mass ratio of 4-ethynylbenzene-1,2-diol, phosphorus oxychloride, and acid-binding agent is 2.8-4.5:4-6:4.2-6.5.

[0019] More preferably, in step S2, the mass ratio of 2,4-dihydroxybenzophenone, potassium carbonate and flame retardant monomer is 2.5-4.5:3-4.5:2.6-4.

[0020] A method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips includes the following steps: Modified chlorinated polyvinyl chloride, ABS resin, polyvinyl chloride resin, heat stabilizer, lubricant, and calcium carbonate are mixed evenly at 80-100℃. The mixture is then fed into a twin-screw extruder and melt-extruded and granulated at 150-170℃ to obtain anti-aging CPVC material.

[0021] The beneficial effects of this invention are: In this invention, the UV-resistant intermediate is first grafted onto CPVC for modification. The introduced azide group then reacts with the antioxidant intermediate via a click reaction to form a stable triazole ring. Ultimately, both the UV-resistant and antioxidant intermediates are firmly anchored to the CPVC via covalent bonds, preventing the migration and precipitation of functional groups at the source. The phenolic hydroxyl group in the UV-resistant intermediate can rapidly capture free radicals generated during the photothermal aging process of CPVC, effectively terminating the oxidation chain reaction and blocking the aging process. Furthermore, the phenolic hydroxyl group forms stable intramolecular hydrogen bonds with the adjacent triazole ring, which not only enhances its own structural stability and extends the free radical capture lifetime, but also forms a synergistic protective system with the benzophenone structure in the antioxidant intermediate. The two complement each other, expanding the UV absorption range and converting high-energy UV radiation into harmless heat or low-energy radiation release, significantly improving the overall UV aging resistance of the material. Meanwhile, the phenolic hydroxyl group can repair the photodegradation products of benzophenone under ultraviolet irradiation through hydrogen donation, effectively prolonging the ultraviolet absorption lifetime of benzophenone, and ultimately constructing a protective network of ultraviolet absorption and free radical capture, so as to realize the long-term and efficient anti-ultraviolet aging of CPVC material and meet the usage requirements of aluminum-plastic composite decorative strips.

[0022] Furthermore, the phosphate ester structure contained in the antioxidant intermediate and the triazole ring structure generated by the click reaction can form a highly efficient phosphorus-nitrogen synergistic flame retardant system. The phosphate ester structure acts as a condensed-phase flame retardant during combustion, catalyzing the dehydration and carbonization of the material to form a dense char layer, effectively isolating oxygen and heat transfer in the combustion zone while suppressing smoke generation. The nitrogen element in the triazole ring structure plays an auxiliary carbonization role, promoting the formation and solidification of the char layer, significantly improving its density and structural stability. Simultaneously, it undergoes thermal decomposition at high temperatures, releasing inert gases, diluting the concentration of combustible gases and oxygen in the combustion environment, and reducing the combustion surface temperature through endothermic thermal decomposition, further blocking the combustion chain reaction. The synergistic effect of these two components achieves a multiphase synergistic flame retardant effect. Moreover, this flame retardant system is firmly anchored to CPVC through covalent bonds, preventing the migration and precipitation of flame retardants, resulting in a more durable and efficient flame retardant effect. Thus, with a relatively low amount of functional component added, the CPVC material achieves excellent flame retardant performance.

[0023] Meanwhile, the phenolic hydroxyl groups introduced into CPVC can form hydrogen bonds with the ethylene-vinyl acetate copolymer adhesive film between the aluminum alloy panel and the CPVC anti-aging core material. The phosphate ester groups and triazole rings in CPVC have polar interactions and dipole-dipole interactions with the adhesive film. The synergistic effect of multiple interfacial forces significantly improves the interlayer bonding force between the CPVC layer and the aluminum alloy panel, thereby enhancing the overall structural stability and preventing problems such as delamination and bulging of aluminum-plastic decorative strips during use. It can adapt to the free splicing requirements of various sizes, ensuring convenient assembly and reliable use. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example

[0025] An anti-aging CPVC material for aluminum-plastic composite decorative strips comprises the following raw materials in parts by weight: 50 parts modified chlorinated polyvinyl chloride, 21% acrylonitrile, 24% butadiene, 20 parts ABS resin with 55% styrene, 8 parts polyvinyl chloride resin, 4 parts methyl tin mercaptan, 2 parts polyethylene wax, and 5 parts calcium carbonate. The preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take 20g of chlorinated polyvinyl chloride into a reactor, add 30g of 15% sodium hydroxide aqueous solution, heat to 70℃, stir and react for 3h to remove hydrogen chloride. Then add the treated chlorinated polyvinyl chloride, 3g of UV-resistant intermediate, 0.5g of benzoyl peroxide, and cyclohexanone into the reactor, heat to 80℃, stir and react for 4h. After the reaction is completed, precipitate the product with ethanol, and then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. Step 2: Take 18g of UV-resistant chlorinated polyvinyl chloride, 2g of antioxidant intermediate, and 0.5g of cuprous bromide into a reactor. Add 100mL of tetrahydrofuran under a nitrogen atmosphere. Remove the oxygen in the reaction solution by three cycles of freezing-vacuuming-melting-nitrogen circulation. Add 0.3g of pentamethyldiethylenetriamine and stir the reaction at room temperature for 12 hours. After the reaction is completed, pour it into a methanol solution for precipitation and filter out the solid. Then wash and dry the obtained solid to obtain modified chlorinated polyvinyl chloride. The preparation method of the anti-UV intermediate includes the following steps: A. Take 4g of 1-(allyloxy)-2-bromobenzene, 1.8g of sodium azide, 0.2g of cuprous iodide, 0.17g of N,N'-dimethylethylenediamine, and 5g of potassium carbonate into a reactor. Add 60mL of N,N-dimethylformamide under a nitrogen atmosphere, heat to 80℃, and stir for 14h. After the reaction is complete, filter to remove the residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take 4g of the UV-resistant precursor into a reactor, add 20mL of nitrobenzene under a nitrogen atmosphere, and react at 200℃ for 5h. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate. The preparation method of the antioxidant intermediate includes the following steps: S1. Take 2.8g of 4-ethynylbenzene-1,2-diol, 4g of phosphorus oxychloride, and 4.2g of triethylamine into a reactor, add 100mL of chloroform, heat to 55℃, stir and react for 3h. After the reaction is complete, filter to remove the solid, remove the solvent by rotary evaporation of the filtrate, and then elute by column chromatography to obtain the flame retardant monomer. S2. Take 2.5g of 2,4-dihydroxybenzophenone and 3g of potassium carbonate in a reactor, add 25mL of cyclohexanone, heat to 30℃, then add 2.6g of flame retardant monomer dropwise. After the addition is complete, heat to 140℃ and stir the reaction for 7h. After the reaction is complete, filter to remove the solid, and remove the solvent from the filtrate by rotary evaporation to obtain the antioxidant intermediate. A method for preparing anti-aging CPVC material for aluminum-plastic composite decorative strips includes the following steps: 50g of modified chlorinated polyvinyl chloride, 20g of ABS resin with 21% acrylonitrile, 24% butadiene, and 55% styrene, 8g of polyvinyl chloride resin, 4g of methyl tin mercaptan, 2g of polyethylene wax, and 5g of calcium carbonate were mixed evenly at 80°C. The mixture was then fed into a twin-screw extruder, melt-extruded at 150°C, and granulated to obtain anti-aging CPVC material. Example

[0026] An anti-aging CPVC material for aluminum-plastic composite decorative strips comprises the following raw materials in parts by weight: 60 parts modified chlorinated polyvinyl chloride, 22% acrylonitrile, 21% butadiene, 40 parts ABS resin with 57% styrene, 10 parts polyvinyl chloride resin, 6 parts octyltin mercaptan, 4 parts oxidized polyethylene wax, and 15 parts calcium carbonate. The preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take 25g of chlorinated polyvinyl chloride into a reactor, add 40g of 5% sodium hydroxide aqueous solution, heat to 80℃, stir and react for 2h to remove hydrogen chloride. Then add the treated chlorinated polyvinyl chloride, 4g of UV-resistant intermediate, 0.6g of benzoyl peroxide, and cyclohexanone into the reactor, heat to 90℃, stir and react for 2h. After the reaction is completed, precipitate the product with ethanol, and then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. Step 2: Take 20g of UV-resistant chlorinated polyvinyl chloride, 3g of antioxidant intermediate, and 0.8g of cuprous bromide into a reactor. Add tetrahydrofuran under a nitrogen atmosphere. Remove the oxygen in the reaction solution by three cycles of freezing-vacuuming-melting-nitrogen circulation. Add 0.5g of pentamethyldiethylenetriamine. Stir the reaction at room temperature for 10 hours. After the reaction is complete, pour it into a methanol solution for precipitation and filter out the solid. Then wash and dry the obtained solid to obtain modified chlorinated polyvinyl chloride. The preparation method of the anti-UV intermediate includes the following steps: A. Take 6g of 1-(allyloxy)-2-bromobenzene, 2.7g of sodium azide, 0.28g of cuprous iodide, 0.26g of N,N'-dimethylethylenediamine, and 7.8g of potassium carbonate into a reactor. Add 100mL of N,N-dimethylformamide under a nitrogen atmosphere, heat to 90℃, and stir for 10h. After the reaction is complete, filter to remove the residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take 6g of the UV-resistant precursor into a reactor, add 60mL of nitrobenzene under a nitrogen atmosphere, and react at 210℃ for 4h. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate. The preparation method of the antioxidant intermediate includes the following steps: S1. Take 4.5g of 4-ethynylbenzene-1,2-diol, 6g of phosphorus oxychloride, and 6.5g of pyridine into a reactor, add 150mL of chloroform, heat to 65℃, stir and react for 2h. After the reaction is complete, filter to remove the solid, remove the solvent by rotary evaporation of the filtrate, and then elute by column chromatography to obtain the flame retardant monomer. S2. Take 4.5g of 2,4-dihydroxybenzophenone and 4.5g of potassium carbonate in a reactor, add 90mL of cyclohexanone, heat to 40℃, then add 4g of flame retardant monomer dropwise. After the addition is complete, heat to 160℃ and stir the reaction for 5h. After the reaction is complete, filter to remove the solid, and remove the solvent by rotary evaporation of the filtrate to obtain the antioxidant intermediate. A method for preparing anti-aging CPVC material for aluminum-plastic composite decorative strips includes the following steps: 60g of modified chlorinated polyvinyl chloride, 40g of ABS resin with 22% acrylonitrile, 21% butadiene, and 57% styrene, 10g of polyvinyl chloride resin, 6g of mercaptan octyltin, 4g of oxidized polyethylene wax, and 15g of calcium carbonate were mixed evenly at 100°C. The mixture was then fed into a twin-screw extruder, melt-extruded at 170°C, and granulated to obtain anti-aging CPVC material. Example

[0027] An anti-aging CPVC material for aluminum-plastic composite decorative strips comprises the following raw materials in parts by weight: 55 parts modified chlorinated polyvinyl chloride, 19% acrylonitrile, 25% butadiene, 30 parts ABS resin with 56% styrene, 9 parts polyvinyl chloride resin, 5 parts octyltin mercaptan, 3 parts polyethylene wax, and 10 parts calcium carbonate. The preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take 23g of chlorinated polyvinyl chloride into a reactor, add 35g of 10% sodium hydroxide aqueous solution, heat to 75℃, stir and react for 2h to remove hydrogen chloride. Then add the treated chlorinated polyvinyl chloride, 3.5g of UV-resistant intermediate, 0.55g of benzoyl peroxide, and cyclohexanone into the reactor, heat to 85℃, stir and react for 3h. After the reaction is completed, precipitate the product with ethanol, and then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. Step 2: Take 19g of UV-resistant chlorinated polyvinyl chloride, 2.5g of antioxidant intermediate, and 0.7g of cuprous bromide into a reactor. Add tetrahydrofuran under a nitrogen atmosphere. Remove the oxygen in the reaction solution by three cycles of freezing-vacuuming-melting-nitrogen circulation. Add 0.42g of pentamethyldiethylenetriamine. Stir the reaction at room temperature for 11 hours. After the reaction is complete, pour it into a methanol solution for precipitation and filter out the solid. Then wash and dry the obtained solid to obtain modified chlorinated polyvinyl chloride. The preparation method of the anti-UV intermediate includes the following steps: A. Take 5g of 1-(allyloxy)-2-bromobenzene, 2.3g of sodium azide, 0.22g of cuprous iodide, 0.2g of N,N'-dimethylethylenediamine, and 6.4g of potassium carbonate in a reactor. Add 60mL of N,N-dimethylformamide under a nitrogen atmosphere, heat to 85℃, and stir for 12h. After the reaction is complete, filter to remove the residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take 5g of the UV-resistant precursor into a reactor, add 50mL of nitrobenzene under a nitrogen atmosphere, and react at 205℃ for 4.5h. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate. The preparation method of the antioxidant intermediate includes the following steps: S1. Take 3.6g of 4-ethynylbenzene-1,2-diol, 5g of phosphorus oxychloride, and 5.3g of triethylamine into a reactor, add 130mL of chloroform, heat to 60℃, stir and react for 2.5h. After the reaction is complete, filter to remove the solid, remove the solvent by rotary evaporation of the filtrate, and then elute by column chromatography to obtain the flame retardant monomer. S2. Take 3.5g of 2,4-dihydroxybenzophenone and 3.8g of potassium carbonate in a reactor, add 70mL of cyclohexanone, heat to 35℃, then add 3.3g of flame retardant monomer dropwise. After the addition is complete, heat to 150℃ and stir the reaction for 6h. After the reaction is complete, filter to remove the solid, and remove the solvent from the filtrate by rotary evaporation to obtain the antioxidant intermediate. A method for preparing anti-aging CPVC material for aluminum-plastic composite decorative strips includes the following steps: 55g of modified chlorinated polyvinyl chloride, 30g of ABS resin with 19% acrylonitrile, 25% butadiene, and 56% styrene, 9g of polyvinyl chloride resin, 5g of mercaptan octyltin, 3g of polyethylene wax, and 10g of calcium carbonate were mixed evenly at 90°C. The mixture was then fed into a twin-screw extruder, melt-extruded at 160°C, and granulated to obtain anti-aging CPVC material.

[0028] Comparative Example 1 An anti-aging CPVC material for aluminum-plastic composite decorative strips comprises the following raw materials in parts by weight: 55 parts modified chlorinated polyvinyl chloride, 19% acrylonitrile, 25% butadiene, 30 parts ABS resin with 56% styrene, 9 parts polyvinyl chloride resin, 5 parts octyltin mercaptan, 3 parts polyethylene wax, and 10 parts calcium carbonate. The preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take 23g of chlorinated polyvinyl chloride into a reactor, add 35g of 10% sodium hydroxide aqueous solution, heat to 75℃, stir and react for 2h to remove hydrogen chloride. Then add the treated chlorinated polyvinyl chloride, 3.5g of UV-resistant intermediate, 0.55g of benzoyl peroxide, and cyclohexanone into the reactor, heat to 85℃, stir and react for 3h. After the reaction is completed, precipitate the product with ethanol, and then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. Step 2: Take 19g of UV-resistant chlorinated polyvinyl chloride, 0.85g of 4-ethynylbenzene-1,2-diol, and 0.7g of cuprous bromide into a reactor. Add tetrahydrofuran under a nitrogen atmosphere. Remove the oxygen in the reaction solution by three cycles of freezing-vacuuming-melting-nitrogen circulation. Add 0.42g of pentamethyldiethylenetriamine. Stir the reaction at room temperature for 11 hours. After the reaction is complete, pour it into a methanol solution for precipitation and filter out the solid. Then wash and dry the obtained solid to obtain modified chlorinated polyvinyl chloride. The preparation method of the anti-UV intermediate includes the following steps: A. Take 5g of 1-(allyloxy)-2-bromobenzene, 2.3g of sodium azide, 0.22g of cuprous iodide, 0.2g of N,N'-dimethylethylenediamine, and 6.4g of potassium carbonate in a reactor. Add 60mL of N,N-dimethylformamide under a nitrogen atmosphere, heat to 85℃, and stir for 12h. After the reaction is complete, filter to remove the residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take 5g of the UV-resistant precursor into a reactor, add 50mL of nitrobenzene under a nitrogen atmosphere, and react at 205℃ for 4.5h. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate. A method for preparing anti-aging CPVC material for aluminum-plastic composite decorative strips includes the following steps: 55g of modified chlorinated polyvinyl chloride, 30g of ABS resin with 19% acrylonitrile, 25% butadiene, and 56% styrene, 9g of polyvinyl chloride resin, 5g of mercaptan octyltin, 3g of polyethylene wax, and 10g of calcium carbonate were mixed evenly at 90°C. The mixture was then fed into a twin-screw extruder, melt-extruded at 160°C, and granulated to obtain anti-aging CPVC material.

[0029] Comparative Example 2 55g of chlorinated polyvinyl chloride, 30g of ABS resin with 19% acrylonitrile, 25% butadiene, and 56% styrene, 9g of polyvinyl chloride resin, 5g of mercaptan octyltin, 3g of polyethylene wax, and 10g of calcium carbonate were mixed evenly at 90°C. The mixture was then fed into a twin-screw extruder, melt-extruded at 160°C, and granulated to obtain anti-aging CPVC material.

[0030] Performance testing Performance tests were conducted on the anti-aging CPVC materials of Examples 1-3 and Comparative Examples 1-2: UV aging resistance test: Referring to GB / T 16422.2-2014, the tensile strength retention rate, elongation at break retention rate and yellow index change of each group of materials after 3000h of UV aging were tested. The obtained UV aging resistance test data are shown in Table 1.

[0031] Table 1: Statistical Table of UV Aging Resistance Test Data

[0032] As can be seen from the data in Table 1, compared with Comparative Example 1 and Comparative Example 2, Examples 1-3 showed higher retention rates of tensile strength and elongation at break after 3000 hours of UV aging, and less change in the yellow index. Compared with Comparative Example 2, the relevant data of Comparative Example 1 also showed a higher level, indicating that the modification of chlorinated polyvinyl chloride with UV-resistant intermediates and antioxidant intermediates can effectively improve the UV aging resistance of chlorinated polyvinyl chloride materials.

[0033] Flame retardancy and interlayer bonding performance tests: The flame retardancy rating of each group of materials was tested according to GB / T 8627-2007, the smoke density rating of each group of materials during combustion was tested according to GB / T 8323.2-2008, and the peel strength between each group of materials and the adhesive film after bonding with the aluminum alloy panel using an ethylene-vinyl acetate copolymer adhesive film was tested according to GB / T 17748-2016. The sample size was 100mm×25mm, and the constant tensile rate was 50mm / min. The obtained flame retardancy and interlayer bonding performance monitoring data are shown in Table 2.

[0034] Table 2: Statistical Table of Monitoring Data on Flame Retardant Performance and Interlayer Bonding Performance

[0035] As can be seen from the data in Table 2, compared with Comparative Examples 1 and 2, Examples 1-3 have higher flame retardancy ratings and peel strengths, and lower smoke density ratings. Compared with Comparative Example 2, Comparative Example 1 also has higher flame retardancy ratings and peel strengths, and lower smoke density ratings. This shows that the modification of chlorinated polyvinyl chloride with UV-resistant intermediates and antioxidant intermediates can effectively improve the flame retardancy and interlayer bonding performance of chlorinated polyvinyl chloride materials.

[0036] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips, characterized in that, The raw materials include the following parts by weight: 50-60 parts modified chlorinated polyvinyl chloride, 20-40 parts ABS resin, 8-10 parts polyvinyl chloride resin, 4-6 parts heat stabilizer, 2-4 parts lubricant, and 5-15 parts calcium carbonate. The modified chlorinated polyvinyl chloride is prepared by a click reaction between chlorinated polyvinyl chloride grafted with an anti-UV intermediate and an antioxidant intermediate; wherein, the anti-UV intermediate is prepared by a nucleophilic substitution reaction between 1-(allyloxy)-2-bromobenzene and sodium azide to obtain an anti-UV precursor, and then by a Claisen rearrangement of the anti-UV precursor; the antioxidant intermediate is prepared by a nucleophilic substitution reaction between 4-ethynylbenzene-1,2-diol and phosphorus oxychloride to obtain a flame retardant monomer, and then by a nucleophilic substitution reaction between the flame retardant monomer and 2,4-dihydroxybenzophenone.

2. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 1, characterized in that, The ABS resin contains 19-22% acrylonitrile, 20-25% butadiene, and 50-57% styrene. The heat stabilizer is methyltin mercaptan or octyltin mercaptan, and the lubricant is polyethylene wax or oxidized polyethylene wax.

3. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 1, characterized in that, The preparation method of modified chlorinated polyvinyl chloride includes the following steps: Step 1: Take chlorinated polyvinyl chloride (PVC) into a reactor, add a 5-15% sodium hydroxide aqueous solution, heat to 70-80℃, stir and react for 1-3 hours to remove hydrogen chloride. Then add the treated PVC, UV-resistant intermediate, benzoyl peroxide, and cyclohexanone into the reactor, heat to 80-90℃, stir and react for 2-4 hours. After the reaction is complete, precipitate the product with ethanol, then filter and dry to obtain UV-resistant chlorinated polyvinyl chloride. The second step involves placing UV-resistant chlorinated polyvinyl chloride, an antioxidant intermediate, and cuprous bromide into a reactor. Tetrahydrofuran is added under a nitrogen atmosphere. The oxygen in the reaction solution is removed by three cycles of freezing, vacuuming, melting, and nitrogen purging. Pentamethyldiethylenetriamine is then added, and the mixture is stirred at room temperature for 10-12 hours. After the reaction is complete, the mixture is poured into a methanol solution for precipitation, and the solid is filtered off. The resulting solid is then washed and dried to obtain modified chlorinated polyvinyl chloride.

4. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 3, characterized in that, In the first step, the mass ratio of chlorinated polyvinyl chloride, sodium hydroxide aqueous solution, UV-resistant intermediate, and benzoyl peroxide is 20-25:30-40:3-4:0.5-0.6; in the second step, the mass ratio of UV-resistant chlorinated polyvinyl chloride, antioxidant intermediate, cuprous bromide, and pentamethyldiethylenetriamine is 18-20:2-3:0.5-0.8:0.3-0.

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5. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 3, characterized in that, The preparation method of the anti-ultraviolet intermediate includes the following steps: A. Take 1-(allyloxy)-2-bromobenzene, sodium azide, cuprous iodide, N,N'-dimethylethylenediamine, and potassium carbonate in a reactor. Add N,N-dimethylformamide under a nitrogen atmosphere, heat to 80-90℃, and stir the reaction for 10-14 hours. After the reaction is completed, filter to remove the filter residue. Extract the filtrate with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and dry to obtain the UV-resistant precursor. B. Take the UV-resistant precursor into the reactor, add nitrobenzene under a nitrogen atmosphere, and react at 200-210℃ for 4-5 hours. After the reaction is completed, extract with ethyl acetate and combine the organic phases. After drying the organic phase, elute by column chromatography to obtain the UV-resistant intermediate.

6. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 5, characterized in that, In step A, the mass ratio of 1-(allyloxy)-2-bromobenzene, sodium azide, cuprous iodide, N,N'-dimethylethylenediamine, and potassium carbonate is 4-6:1.8-2.7:0.2-0.28:0.17-0.26:5-7.

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7. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 3, characterized in that, The preparation method of the antioxidant intermediate includes the following steps: S1. Take 4-ethynylbenzene-1,2-diol, phosphorus oxychloride, and acid-binding agent into a reactor, add chloroform, heat to 55-65℃, stir the reaction for 2-3 hours, filter to remove solid after the reaction, remove solvent by rotary evaporation of filtrate, and then elute by column chromatography to obtain flame retardant monomer. S2. Take 2,4-dihydroxybenzophenone and potassium carbonate in a reactor, add cyclohexanone, heat to 30-40℃, then add flame retardant monomer dropwise. After the addition is complete, heat to 140-160℃ and stir the reaction for 5-7 hours. After the reaction is complete, filter to remove the solid, and remove the solvent by rotary evaporation of the filtrate to obtain the antioxidant intermediate.

8. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 7, characterized in that, The acid-binding agent in step S1 is pyridine or triethylamine, and the mass ratio of 4-ethynylbenzene-1,2-diol, phosphorus oxychloride, and the acid-binding agent is 2.8-4.5:4-6:4.2-6.

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9. The method for preparing an anti-aging CPVC material for aluminum-plastic composite decorative strips according to claim 7, characterized in that, In step S2, the mass ratio of 2,4-dihydroxybenzophenone, potassium carbonate, and flame retardant monomer is 2.5-4.5:3-4.5:2.6-4.

10. The method for preparing the anti-aging CPVC material for aluminum-plastic composite decorative strips according to any one of claims 1-9, characterized in that, Includes the following steps: Modified chlorinated polyvinyl chloride, ABS resin, polyvinyl chloride resin, heat stabilizer, lubricant, and calcium carbonate are mixed evenly at 80-100℃. The mixture is then fed into a twin-screw extruder and melt-extruded and granulated at 150-170℃ to obtain anti-aging CPVC material.

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