An outdoor anti-aging acrylic resin coating and its preparation method

Abstract

This invention relates to the field of coating technology, specifically to an outdoor anti-aging acrylic resin coating and its preparation method. The coating comprises a grafted modified hydroxyl acrylic resin component, butyl acetate, propylene glycol methyl ether acetate, and an aliphatic hexamethylene diisocyanate trimer curing agent. The grafted modified hydroxyl acrylic resin component is prepared by introducing suspended methacrylate double bonds into hydroxyl acrylic resin via 2-isocyanoethyl methacrylate, followed by segmental grafting of hindered amine methacrylate monomers, benzotriazole methacrylate monomers, and methacryloyloxysilane-treated fumed silica. This coating can reduce the migration of light-stabilizing components and the aggregation of nanofillers, improving the gloss retention, color difference stability, chalking grade, haze stability, and flexibility retention of the coating film after outdoor aging. It is suitable for surface protection of wood, rigid PVC profiles, and flexible PVC decorative films.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to an outdoor anti-aging acrylic resin coating and its preparation method. Background Technology

[0002] Outdoor acrylic resin coatings are widely used for the protection and decoration of building exteriors, woodwork, and plastic building materials. Among them, two-component acrylic polyurethane systems have become the mainstream choice due to their combination of hardness and flexibility. To improve weather resistance, the industry generally adopts physical blending to add hindered amine light stabilizers, benzotriazole UV absorbers, and nano-silica fillers to the resin.

[0003] However, in practical applications, small molecule light stabilizers are prone to migration and extraction as the temperature rises or they come into contact with solvents, resulting in the loss of protective components on the coating surface and a sharp drop in long-term anti-aging performance. Unmodified nano-silica, due to its high surface energy, is very easy to agglomerate in resin, which not only causes an increase in coating haze but also leads to problems such as increased brittleness and decreased flexibility, especially in transparent or semi-transparent topcoats.

[0004] In addition, the simple mixing of light stabilizers and fillers in traditional processes makes it difficult to achieve uniform distribution. Local concentration differences further exacerbate the uncontrollability of coating performance, leading to defects such as loss of gloss, chalking, and cracking after outdoor use. This fails to meet the stringent requirements of long-term weather resistance and appearance retention for substrates such as wood, PVC plastic profiles, and flexible decorative films. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an outdoor anti-aging acrylic resin coating and its preparation method, so as to solve the problems in the prior art where physical blending light stabilizers are easily migrated and extracted, and nanofillers are easily agglossed, resulting in loss of gloss, chalking, increased haze and decreased flexibility of the coating film after long-term aging.

[0006] To achieve the above objectives, the present invention provides an outdoor anti-aging acrylic resin coating, characterized in that it comprises a grafted modified hydroxyl acrylic resin component, butyl acetate, propylene glycol methyl ether acetate and an aliphatic hexamethylene diisocyanate trimer curing agent.

[0007] The coating is prepared from the following raw materials by weight: 500 parts of grafted modified hydroxyl acrylic resin component, 50-70 parts of butyl acetate, 10-30 parts of propylene glycol methyl ether acetate and 95-125 parts of aliphatic hexamethylene diisocyanate trimer curing agent.

[0008] The grafted modified hydroxyl acrylic resin component has a hydroxyl acrylic resin molecular chain, a carbamate linker formed by the reaction of ethyl methacrylate-2-isocyanate with a hydroxyl group, and a methacrylate grafted segment connected to the linker; the grafted segment contains a hindered amine structural unit and a benzotriazole ultraviolet absorbing structural unit, and the methacrylic silane-treated fumed silica is dispersed in the grafted modified hydroxyl acrylic resin component.

[0009] Based on 1000 parts of the hydroxyl acrylic resin, the grafted modified hydroxyl acrylic resin component is prepared from the following raw materials: 1000 parts of hydroxyl acrylic resin, 20-40 parts of ethyl methacrylate-2-isocyanate, 55-85 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 15-30 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 10-21 parts of methacrylic silane-treated fumed silica, 3.5-6.8 parts of azobisisobutyronitrile, 0.15-0.45 parts of dibutyltin dilaurate, and 290-455 parts of butyl acetate.

[0010] Preferably, the hydroxyl acrylic resin is a solvent-based hydroxyl acrylic polyol resin, with a hydroxyl content of 4%-5% and a non-volatile content of 65%-75% based on non-volatile matter.

[0011] Preferably, the methacrylic silane-treated fumed silica is a structurally modified fumed silica treated with methacrylic silane, with a silica content of not less than 99.8% and a specific surface area of ​​100-200 m². 2 / g.

[0012] Preferably, the isocyanate group content of the aliphatic hexamethylene diisocyanate trimer curing agent is 18%-21%.

[0013] Furthermore, the present invention also provides a method for preparing an outdoor anti-aging acrylic resin coating, comprising the following steps:

[0014] S1. Hydroxyacrylate resin and butyl acetate are mixed and dehydrated to obtain a dehydrated resin solution;

[0015] S2. In the presence of dibutyltin dilaurate, ethyl methacrylate-2-isocyanate is reacted with hydroxy acrylic resin in the dehydrated resin solution to obtain a hydroxy acrylic resin intermediate containing a suspended methacrylate double bond.

[0016] S3. 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, methacrylic silane-treated fumed silica, butyl acetate, and azobisisobutyronitrile are formulated into a first grafting feed solution, and the first grafting feed solution is added to the hydroxyl acrylic resin intermediate containing the suspended methacrylate double bond to carry out the first grafting reaction;

[0017] S4. 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, methacrylic silane-treated fumed silica, butyl acetate, and azobisisobutyronitrile are prepared to form a second grafting feed solution. The second grafting feed solution is added to the reaction system obtained in step S3 to carry out the second grafting reaction. Butyl acetate and azobisisobutyronitrile are then added to continue the reaction.

[0018] S5. Add butyl acetate to the system obtained in step S4, stir, cool and filter to obtain the grafted modified hydroxyl acrylic resin component.

[0019] S6. The grafted modified hydroxyl acrylic resin component is mixed with butyl acetate, propylene glycol methyl ether acetate and aliphatic hexamethylene diisocyanate trimer curing agent to obtain an outdoor anti-aging acrylic resin coating.

[0020] Preferably, in step S3, under light-protected conditions, based on 1000 parts of the hydroxy acrylic resin, 15-25 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 12-22 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 1-5 parts of methacrylic silane-treated fumed silica, 30-55 parts of butyl acetate, and 1.5-2.5 parts of azobisisobutyronitrile are added to a dispersion container and dispersed at 500-700 rpm for 25-35 min to obtain the first grafting feed solution; the hydroxy acrylic resin intermediate containing the suspended methacrylate double bond obtained in step S2 is heated to 72-76°C, and the first grafting feed solution is added dropwise over 50-70 min under stirring at 300 rpm and nitrogen protection, and after the dropwise addition is completed, the temperature is maintained at 72-76°C for 20-40 min.

[0021] Preferably, in step S4, under light-protected conditions, based on 1000 parts of the hydroxyl acrylic resin, 40-60 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 3-8 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 9-16 parts of methacrylic silane-treated fumed silica, 65-95 parts of butyl acetate, and 1.5-2.8 parts of azobisisobutyronitrile are added to a dispersion container and dispersed at 700-900 rpm for 35-45 min to obtain a second grafting feed solution; the reaction system obtained in step S3 is heated to 76-80℃, and the second grafting feed solution is added dropwise over 80-100 min; after the dropwise addition is completed, 15-25 parts of butyl acetate and 0.5-1.5 parts of azobisisobutyronitrile are added, and the reaction is continued at 76-80℃ for 2.5-3.5 h.

[0022] Furthermore, the present invention also provides an outdoor anti-aging acrylic resin coating film, which is formed by curing an outdoor anti-aging acrylic resin coating prepared by an outdoor anti-aging acrylic resin paint or a method for preparing an outdoor anti-aging acrylic resin paint.

[0023] Preferably, the coating is formed on the surface of wood, PVC plastic profile or flexible PVC decorative film, and the dry film thickness of the coating is 45±5μm.

[0024] The beneficial effects of this invention are:

[0025] (1) This invention constructs urethane linkers and dangling double bonds on the side chains of hydroxyacrylic acid resin using ethyl methacrylate-2-isocyanate, allowing hindered amines and benzotriazole UV absorption units to be covalently grafted onto the resin molecular chain, fundamentally solving the problems of migration and solvent extraction of small molecule light stabilizers. Data shows that the isopropanol immersion mass loss rate of Example 1 is only 1.3%, far lower than that of the physically blended Comparative Example 2 (5.1%) and Comparative Example 3 (3.2%). After 1000h aging, the 60° gloss retention rate reaches 92.4%, the chalking grade is 0, and the color difference ΔE is only 1.31, achieving a long-term stable light protection effect.

[0026] (2) The process of treating fumed silica with methacrylic silane and adding it in stages allows the reactive groups on its surface to form chemical bonds with the resin matrix, which avoids the increase in haze caused by agglomeration and improves the flexibility of the coating. The haze increase value of Example 1 is only 1.2%, and the elongation at break retention rate is 77.2%, which is significantly better than Comparative Example 4 with untreated silica (haze increase of 4.6%, elongation at break retention rate of 60.2%) and Comparative Example 5 with one-time addition (haze increase of 3.8%, elongation at break retention rate of 64.3%), achieving a balance between high light transmittance and high toughness in transparent / semi-transparent substrate coatings.

[0027] (3) The grafted resin retains its remaining hydroxyl groups, and after curing with the aliphatic hexamethylene diisocyanate trimer, it forms an interpenetrating network structure, which synergistically improves the coating's weather resistance, adhesion, and mechanical properties. In Example 3, even after increasing the amount of functional components, the gloss retention rate after 1000 hours of aging still reached 94.8%, the color difference ΔE was only 1.12, and the cross-cut grade remained at level 0. It is suitable for long-term outdoor protection of various substrates such as wood, rigid PVC profiles, and flexible PVC films. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] Raw material source and model:

[0030] The hydroxy acrylic resin used is SETALUX1753SS-70, which is available through Allnex's China business channels. The supplier is Allnex. This raw material is a solvent-based hydroxy acrylic polyol resin with a hydroxyl content of 4.2% and a non-volatile content of 70%.

[0031] 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole was selected from H1261 of TICE (Shanghai) Chemical Industry Development Co., Ltd., CAS No. 96478-09-0.

[0032] The fumed silica treated with methacrylic silane was selected from Evonik's AEROSIL R7200. This raw material is structurally modified fumed silica treated with methacrylic silane, with a silica content of not less than 99.8% and a specific surface area of ​​150 m². 2 / g.

[0033] The aliphatic hexamethylene diisocyanate trimer curing agent used is Covestro Desmodurultra N3390BA / SN, with an isocyanate group content of 19.5%.

[0034] The wood substrate is selected from the same batch of knot-free pine planks; the PVC plastic profiles are selected from the same batch of white rigid PVC profile samples; and the flexible PVC decorative film is selected from the same batch of transparent flexible PVC decorative film with a thickness of 0.20mm.

[0035] Example 1:

[0036] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 120g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it down to 50℃.

[0037] Step 2: Under stirring conditions of 50℃ and 300rpm, add 300mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 30g of ethyl 2-isocyanate methacrylate and 30g of butyl acetate for 10min, add them dropwise to the reaction system over 40min; after the addition is complete, raise the temperature to 60℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0038] Step 3: Under light-protected conditions, 20g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 18g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 3g of methacrylic silane-treated fumed silica, 40g of butyl acetate, and 2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 600 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 75℃, and the first grafting feed solution was added dropwise over 60 min under stirring at 300 rpm and nitrogen protection, and then kept at 75℃ for 30 min after the addition was completed;

[0039] Step 4: Under light-protected conditions, 50g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 5g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 12g of methacrylic silane-treated fumed silica, 80g of butyl acetate, and 2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 800 rpm for 40 min to obtain the second grafting feed solution; the reaction system obtained in Step 3 was heated to 78℃, and the second grafting feed solution was added dropwise over 90 min; after the dropwise addition was completed, 20g of butyl acetate and 1g of azobisisobutyronitrile were added, and the reaction was continued at 78℃ for 3 h;

[0040] Step 5: Add 80g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0041] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 60g of butyl acetate and 20g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 110g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain outdoor anti-aging acrylic resin coating.

[0042] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0043] Example 2:

[0044] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 110g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it to 50℃.

[0045] Step 2: Under stirring conditions of 50℃ and 300rpm, add 200mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 20g of ethyl methacrylate-2-isocyanate and 20g of butyl acetate for 10min, add them dropwise to the reaction system over 35min; after the addition is complete, raise the temperature to 58℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0046] Step 3: Under light-protected conditions, 15g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 14g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2g of methacrylic silane-treated fumed silica, 38g of butyl acetate, and 1.8g of azobisisobutyronitrile were added to a dispersion container and dispersed at 600 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 74℃, and the first grafting feed solution was added dropwise over 60 min under stirring at 300 rpm and nitrogen protection, and then kept at 74℃ for 30 min after the addition was completed;

[0047] Step 4: Under light-protected conditions, 45g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 4g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 10g of methacrylic silane-treated fumed silica, 75g of butyl acetate, and 1.8g of azobisisobutyronitrile were added to a dispersion container and dispersed at 800 rpm for 40 min to obtain the second grafting feed solution. The reaction system obtained in Step 3 was heated to 77℃, and the second grafting feed solution was added dropwise over 90 min. After the dropwise addition was completed, 20g of butyl acetate and 0.8g of azobisisobutyronitrile were added, and the reaction was continued at 77℃ for 3 h.

[0048] Step 5: Add 75g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0049] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 60g of butyl acetate and 20g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 115g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain outdoor anti-aging acrylic resin coating.

[0050] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0051] Example 3:

[0052] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 130g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it to 50℃.

[0053] Step 2: Under stirring conditions of 50℃ and 300rpm, add 400mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 40g of ethyl 2-isocyanate methacrylate and 40g of butyl acetate for 10min, add them dropwise to the reaction system over 50min; after the addition is complete, raise the temperature to 62℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0054] Step 3: Under light-protected conditions, 24g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 21g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 5g of methacrylic silane-treated fumed silica, 50g of butyl acetate, and 2.4g of azobisisobutyronitrile were added to a dispersion container and dispersed at 650 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 76℃, and the first grafting feed solution was added dropwise over 70 min under stirring at 300 rpm and nitrogen protection. After the dropwise addition was completed, the solution was kept at 76℃ for 30 min.

[0055] Step 4: Under light-protected conditions, 56g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 7g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 13g of methacrylic silane-treated fumed silica, 90g of butyl acetate, and 2.4g of azobisisobutyronitrile were added to a dispersion container and dispersed at 850 rpm for 40 min to obtain the second grafting feed solution. The reaction system obtained in Step 3 was heated to 80℃, and the second grafting feed solution was added dropwise over 100 min. After the dropwise addition was completed, 25g of butyl acetate and 1.2g of azobisisobutyronitrile were added, and the reaction was continued at 80℃ for 3 h.

[0056] Step 5: Add 90g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0057] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 65g of butyl acetate and 25g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 105g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain an outdoor anti-aging acrylic resin coating.

[0058] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0059] Example 4:

[0060] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 125g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it to 50℃.

[0061] Step 2: Under stirring conditions of 50℃ and 300rpm, add 300mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 30g of ethyl 2-isocyanate methacrylate and 30g of butyl acetate for 10min, add them dropwise to the reaction system over 40min; after the addition is complete, raise the temperature to 60℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0062] Step 3: Under light-protected conditions, 25g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 15g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 3g of methacrylic silane-treated fumed silica, 45g of butyl acetate, and 2.2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 600 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 75℃, and the first grafting feed solution was added dropwise over 60 min under stirring at 300 rpm and nitrogen protection. After the addition was completed, the solution was kept at 75℃ for 30 min.

[0063] Step 4: Under light-protected conditions, 60g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 5g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 12g of methacrylic silane-treated fumed silica, 85g of butyl acetate, and 2.2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 800 rpm for 40 min to obtain the second grafting feed solution; the reaction system obtained in Step 3 was heated to 78℃, and the second grafting feed solution was added dropwise over 90 min; after the dropwise addition was completed, 20g of butyl acetate and 1g of azobisisobutyronitrile were added, and the reaction was continued at 78℃ for 3 h;

[0064] Step 5: Add 85g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0065] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 60g of butyl acetate and 20g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 110g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain outdoor anti-aging acrylic resin coating.

[0066] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0067] Example 5:

[0068] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 135g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it to 50℃.

[0069] Step 2: Under stirring conditions of 50℃ and 300rpm, add 350mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 35g of ethyl methacrylate-2-isocyanate and 35g of butyl acetate for 10min, add them dropwise to the reaction system over 45min; after the addition is complete, raise the temperature to 61℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0070] Step 3: Under light-protected conditions, 18g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 19g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 4g of methacrylic silane-treated fumed silica, 48g of butyl acetate, and 2.3g of azobisisobutyronitrile were added to a dispersion container and dispersed at 650 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 75℃, and the first grafting feed solution was added dropwise over 65 min under stirring at 300 rpm and nitrogen protection, and then kept at 75℃ for 30 min after the addition was completed;

[0071] Step 4: Under light-protected conditions, 47g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 6g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 16g of methacrylic silane-treated fumed silica, 90g of butyl acetate, and 2.3g of azobisisobutyronitrile were added to a dispersion container and dispersed at 850 rpm for 40 min to obtain the second grafting feed solution. The reaction system obtained in Step 3 was heated to 79℃, and the second grafting feed solution was added dropwise over 95 min. After the dropwise addition was completed, 25g of butyl acetate and 1.1g of azobisisobutyronitrile were added, and the reaction was continued at 79℃ for 3 h.

[0072] Step 5: Add 90g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0073] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 65g of butyl acetate and 25g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 108g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain outdoor anti-aging acrylic resin coating.

[0074] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0075] Example 6:

[0076] Step 1: Dry the reaction vessel equipped with stirring, condensation and nitrogen inlet at 110℃ for 60 min, cool it to 25℃ and then introduce dry nitrogen; add 1000g of hydroxyl acrylic resin and 115g of butyl acetate to the reaction vessel, and introduce dry nitrogen for 30 min while stirring at 300 rpm; then raise the temperature to 60℃, dehydrate it under -70kPa gauge pressure for 60 min, and then cool it to 50℃.

[0077] Step 2: Under stirring conditions of 50℃ and 300rpm, add 250mg of dibutyltin dilaurate to the system obtained in Step 1; after premixing 25g of ethyl methacrylate-2-isocyanate and 25g of butyl acetate for 10min, add them dropwise to the reaction system over 40min; after the addition is complete, raise the temperature to 59℃ and keep it at that temperature for 3h to obtain a hydroxyl acrylic resin intermediate containing a suspended methacrylate double bond;

[0078] Step 3: Under light-protected conditions, 20g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 17g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 3g of methacrylic silane-treated fumed silica, 42g of butyl acetate, and 2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 600 rpm for 30 min to obtain the first grafting feed solution; the hydroxyl acrylic resin intermediate obtained in Step 2 was heated to 75℃, and the first grafting feed solution was added dropwise over 60 min under stirring at 300 rpm and nitrogen protection, and then kept at 75℃ for 30 min after the addition was completed;

[0079] Step 4: Under light-protected conditions, 50g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 5g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 11g of methacrylic silane-treated fumed silica, 78g of butyl acetate, and 2g of azobisisobutyronitrile were added to a dispersion container and dispersed at 800 rpm for 40 min to obtain the second grafting feed solution; the reaction system obtained in Step 3 was heated to 78℃, and the second grafting feed solution was added dropwise over 90 min; after the dropwise addition was completed, 20g of butyl acetate and 1g of azobisisobutyronitrile were added, and the reaction was continued at 78℃ for 3 h;

[0080] Step 5: Add 80g of butyl acetate to the system obtained in Step 4, stir at 300rpm for 20min and cool to 40℃, then filter through a 25μm filter bag to obtain the grafted modified hydroxyl acrylic resin component.

[0081] Step 6: Take 500g of grafted modified hydroxyl acrylic resin component, add 55g of butyl acetate and 20g of propylene glycol methyl ether acetate, and stir at 300rpm for 30min; then add 113g of aliphatic hexamethylene diisocyanate trimer curing agent, and continue stirring at 300rpm for 20min to obtain outdoor anti-aging acrylic resin coating.

[0082] Step 7: Apply the outdoor anti-aging acrylic resin coating obtained in Step 6 using a 120μm wire rod to the following surfaces: wood surface sanded and dust-free with 240-grit sandpaper, PVC plastic profile surface wiped with isopropyl alcohol for 60s, and flexible PVC decorative film surface treated with corona to a surface tension ≥38mN / m. After coating, place at 25℃ and 50% relative humidity for 30min, then cure at 80℃ for 60min, and finally cure at 25℃ and 50% relative humidity for 7d to obtain the outdoor anti-aging acrylic resin coating film.

[0083] Comparative Example 1:

[0084] The difference from Example 1 is that: in step two, 30g of ethyl 2-isocyanate methacrylate is not added, and the 30g of ethyl 2-isocyanate methacrylate is replaced with 30g of butyl acetate. In step two, 300mg of dibutyltin dilaurate is still added, and the temperature is still maintained at 60°C for 3h; the other conditions are the same as in Example 1.

[0085] Comparative Example 2:

[0086] The difference from Example 1 is that 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate is not added in steps three and four. Instead, the 20g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate in step three and the 50g of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate in step four of Example 1, totaling 70g, is added all at once in step five after cooling to 40°C. The mixture is then stirred at 300 rpm for 20 minutes and filtered. The remaining conditions are the same as in Example 1.

[0087] Comparative Example 3:

[0088] The difference from Example 1 is that 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole is not added in steps three and four. Instead, the 18g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole in step three and the 5g of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole in step four of Example 1, totaling 23g, is added all at once in step five after cooling to 40°C, and then stirred at 300rpm for 20min before filtration. The remaining conditions are the same as in Example 1.

[0089] Comparative Example 4:

[0090] The difference from Example 1 is that the 3g of methacrylic silane-treated fumed silica in step three and the 12g of methacrylic silane-treated fumed silica in step four are replaced with 3g of untreated fumed silica and 12g of untreated fumed silica, respectively, to keep the total amount of fumed silica unchanged at 15g; the other conditions are the same as in Example 1.

[0091] Comparative Example 5:

[0092] The difference from Example 1 is that: in step three, 3g of methacrylsilane is not added to treat fumed silica; in step four, the amount of methacrylsilane used to treat fumed silica is adjusted from 12g to 15g, that is, all the methacrylsilane used to treat fumed silica is added at once in the second grafting feed liquid, and the total amount of methacrylsilane used to treat fumed silica is still 15g; the other conditions are the same as in Example 1.

[0093] Comparative Example 6:

[0094] The difference from Example 1 is that the amount of ethyl 2-isocyanate methacrylate added in step 2 is adjusted from 30g to 10g, and the amount of butyl acetate premixed with ethyl 2-isocyanate methacrylate is adjusted from 30g to 50g, so as to keep the total mass of the feed in step 2 unchanged; the other conditions are the same as in Example 1.

[0095] Comparative Example 7:

[0096] The difference from Example 1 is that the amount of ethyl 2-isocyanate methacrylate added in step 2 is adjusted from 30g to 50g, and the amount of butyl acetate premixed with ethyl 2-isocyanate methacrylate is adjusted from 30g to 10g, so as to keep the total mass of the feed in step 2 unchanged; the other conditions are the same as in Example 1.

[0097] Performance test sample preparation: The outdoor anti-aging acrylic resin coatings obtained in Examples 1-6 and Comparative Examples 1-7 were used as test samples. Unless otherwise specified in the intrinsic characterization, the coatings for each test sample were prepared in the same manner: the coatings were applied using a 120 μm wire rod to a pine wood sample that had been sanded and dusted with 240-grit sandpaper, a white rigid PVC plastic profile sample that had been wiped with isopropyl alcohol for 60 s, and a transparent flexible PVC decorative film that had been corona treated to a surface tension ≥38 mN / m; after coating, the samples were placed at 25℃ and 50% relative humidity for 30 min, then cured at 80℃ for 60 min, and finally cured at 25℃ and 50% relative humidity for 7 days. The dry film thickness was determined according to GB / T 13452.2-2008, and the sample with a dry film thickness of 45±5 μm was retained for subsequent tests. For each test item, three parallel samples were prepared for each embodiment or comparative example. Except for the graded results, the arithmetic mean of the three samples was taken as the test result of that sample. For the graded results, the grade that appeared most frequently among the three samples was taken as the test result of that sample.

[0098] Non-volatile content: The non-volatile content of the grafted modified hydroxyl acrylic resin components obtained in step five of Examples 1-6 and Comparative Examples 1-7 was determined according to GB / T 1725-2007. 1.000±0.010 g of sample was weighed and placed in a pre-weighed aluminum dish. The sample was spread into a uniform thin layer and heated in a 105℃ forced-air drying oven for 1 hour. After removal, it was placed in a desiccator to cool for 30 minutes and weighed. The non-volatile content was calculated as a percentage of the residual mass after drying to the initial sample mass.

[0099] Gloss, color difference, and chalking grade after artificial weathering: Artificial weathering tests with filtered xenon arc radiation were conducted on the coatings of Examples 1-6 and Comparative Examples 1-7 on white rigid PVC profile samples according to GB / T 1865-2009. The test conditions were: irradiance 0.51 W / m². 2The control wavelength was 340nm, the black standard temperature was 65℃, the relative humidity inside the chamber was 50%, the circulation method was 102min of light exposure and 18min of light spraying, the conductivity of the spraying water was less than 5μS / cm, and the total exposure time was 1000h. Before and after aging, the specular gloss at the same location was measured under 60° geometric conditions according to GB / T 9754-2025. Five points were measured for each sample and the average value was taken. The 60° gloss retention rate was calculated by dividing the 60° gloss after aging by the 60° gloss before aging and then multiplying by 100. Before and after aging, the coating color was measured according to GB / T 11186-2025, using a D65 standard illuminator and a 10° observer condition, and the color difference ΔE after aging was calculated relative to before aging. After aging, the chalking grade was assessed using the tape method according to GB / T 30789.6-2015. The tape was pasted in the middle of the sample and peeled off at a uniform speed in a 180° direction. The residue on the tape was compared with the chalking grade chart and the grade was recorded.

[0100] Cross-cut rating after artificial climate aging: On white rigid PVC profile samples that have undergone 1000 hours of artificial climate aging, a cross-cut test was conducted according to GB / T 9286-2021. A manual single-blade cutter was used, with a cutting interval of 2mm and 6 × 6 cuts, reaching the surface of the substrate. After cutting, a soft brush was used to lightly brush along the diagonal of the grid 5 times, and then pressure-sensitive adhesive tape meeting the test requirements was applied. After the tape was applied, it was continuously peeled off in a near 180° direction within 5 minutes. The degree of peeling off the grid area was observed and the cross-cut rating was recorded.

[0101] Mass loss rate after isopropanol immersion: The extraction resistance of the coatings in Examples 1-6 and Comparative Examples 1-7 was evaluated according to the immersion method of GB / T 9274-1988. Each coating was applied to the surface of a polytetrafluoroethylene release film using a 120μm wire rod. Free coatings were prepared by placing the film at 25℃ for 30 min, curing at 80℃ for 60 min, and curing at 25℃ and 50% relative humidity for 7 days. A 25mm × 50mm free coating was cut off, and the initial mass m0 was recorded. The film was completely immersed in 50mL of isopropanol and placed in a sealed container at 25℃ for 24h. After removal, the surface liquid was gently wiped off with lint-free paper, and the film was placed at 25℃ for 30 min, then dried at 80℃ for 30 min. Finally, the film was equilibrated at 25℃ and 50% relative humidity for 24h, and the mass m1 was recorded. The mass loss rate after isopropanol immersion was calculated as (m0-m1) / m0 × 100.

[0102] Elongation at break retention rate of flexible PVC decorative film: The elongation at break retention rate of composite coating strips formed on the surface of transparent flexible PVC decorative film in Examples 1-6 and Comparative Examples 1-7 was determined according to GB / T 1040.3-2006. The coated flexible PVC decorative film, after 7 days of curing, was cut into 150mm × 15mm strips with a gauge length of 50mm and a tensile speed of 100mm / min. The elongation at break before aging was tested. Another strip from the same batch was exposed to the above artificial climate aging conditions for 1000h, and then equilibrated at 25℃ and 50% relative humidity for 24h before testing the elongation at break after aging. The elongation at break retention rate was calculated by dividing the elongation at break after aging by the elongation at break before aging and then multiplying by 100.

[0103] Haze increase: The haze of the composite coatings formed on the surface of transparent flexible PVC decorative films in Examples 1-6 and Comparative Examples 1-7 was determined according to GB / T 2410-2008. The initial haze of the coated transparent flexible PVC decorative films after 7 days of curing was measured using a haze meter. Five locations were measured for each sample, and the average value was taken. Another sample from the same batch was exposed to the above artificial climate aging conditions for 1000 hours, and then equilibrated for 24 hours at 25℃ and 50% relative humidity before the haze was measured after aging. The haze increase was calculated by subtracting the initial haze from the haze after aging.

[0104] Table 1 Performance Test Results

[0105]

[0106] As shown in Table 1, Comparative Example 1 did not introduce suspended methacrylate double bonds into the side chains of the hydroxyl acrylic resin. The hindered amine monomer, benzotriazole UV-absorbing monomer, and fumed silica were difficult to effectively anchor in the resin network. After 1000 hours of artificial weathering, the 60° gloss retention rate was only 66.5%, the color difference ΔE reached 4.85, the chalking grade was 4, and the mass loss rate after isopropanol immersion was 4.6%. This indicates that relying solely on the original hydroxyl acrylic resin and aliphatic isocyanate curing network is insufficient to simultaneously meet the long-term anti-aging and anti-migration requirements of outdoor transparent or semi-transparent coatings.

[0107] Compared with Comparative Example 1, Example 1 uses ethyl methacrylate-2-isocyanate to form urethane linkers and dangling double bonds that can participate in free radical grafting on the side chains of hydroxyacrylate resin. Furthermore, 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, reactive benzotriazole UV-absorbing monomer, and methacrylic silane-treated fumed silica are introduced into the resin system in segments. This results in an increase in the 60° gloss retention rate to 92.4% after 1000h aging, a decrease in color difference ΔE to 1.31, a reduction in chalking grade to 0, and a decrease in mass loss rate after isopropanol immersion to 1.3%. This indicates that the above functional components, when distributed in a relatively stable manner in the coating network, can effectively reduce the performance degradation caused by photo-oxidative aging and solvent extraction.

[0108] Although Comparative Examples 2 and 3 added the same amount of hindered amine monomer and benzotriazole UV-absorbing monomer as in Example 1, they were added later. After 1000 hours of aging, the 60° gloss retention rates were only 73.8% and 69.4%, respectively, and the mass loss rates after isopropanol immersion were 5.1% and 3.2%, respectively. This indicates that free small molecule photostable components are more likely to migrate or be extracted under long-term aging and solvent action, making it difficult to form a continuous and stable photoprotective effect.

[0109] Comparative Example 4 used untreated fumed silica instead of methacryl silane-treated fumed silica, while Comparative Example 5 added methacryl silane-treated fumed silica all at once. The haze increase values ​​of the two increased to 4.6% and 3.8%, respectively, and the elongation at break retention rates decreased to 60.2% and 64.3%, respectively. This indicates that the surface reactivity of silica and the segmented addition method play an important role in maintaining transparency and flexibility.

[0110] In Examples 1-6, Example 3, due to its higher dosage of ethyl 2-isocyanate methacrylate, hindered amine monomer, benzotriazole UV-absorbing monomer, and methacrylic silane-treated fumed silica, achieved a 94.8% gloss retention rate at 60° after 1000 hours of aging, and a color difference ΔE reduced to 1.12, demonstrating stronger long-term weather resistance. However, its elongation at break and elongation at break retention rate before aging were lower than those of Examples 2 and 6, indicating that excessive dosage of functional monomers and inorganic nanophases can affect the flexibility of the coating film. Examples 2 and 6, under conditions of lower grafting density or lower ethyl 2-isocyanate methacrylate dosage, still maintained gloss retention rates of 88.6% and 90.7%, respectively, and elongation at break retention rates of 79.4% and 78.7%, respectively, indicating that the formulation of this invention has certain adaptability in different application viscosities and flexible substrate overlay scenarios.

[0111] As shown in Table 1, the present invention utilizes a combination of side-chain suspended double bond anchoring, reactive hindered amine radical capturing units, reactive benzotriazole UV absorption units, and methacrylic silane-treated fumed silica to construct a segmented nano-shielding phase. This combination enables the coating to maintain high gloss, low color difference, low chalking level, low extraction loss, good cross-cutting grade, and low haze increase value after 1000 hours of artificial climate aging, demonstrating a synergistic effect of anti-migration, anti-chalking, low haze, and flexibility retention.

[0112] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An outdoor anti-aging acrylic resin coating, characterized in that, Includes grafted modified hydroxyl acrylic resin components, butyl acetate, propylene glycol methyl ether acetate, and aliphatic hexamethylene diisocyanate trimer curing agent; The coating is prepared from the following raw materials by weight: 500 parts of grafted modified hydroxyl acrylic resin component, 50-70 parts of butyl acetate, 10-30 parts of propylene glycol methyl ether acetate and 95-125 parts of aliphatic hexamethylene diisocyanate trimer curing agent. The grafted modified hydroxyl acrylic resin component has a hydroxyl acrylic resin molecular chain, a carbamate linker formed by the reaction of ethyl methacrylate-2-isocyanate with a hydroxyl group, and a methacrylate grafted segment connected to the linker; the grafted segment contains a hindered amine structural unit and a benzotriazole ultraviolet absorbing structural unit, and the methacrylic silane-treated fumed silica is dispersed in the grafted modified hydroxyl acrylic resin component. Based on 1000 parts of the hydroxyl acrylic resin, the grafted modified hydroxyl acrylic resin component is prepared from the following raw materials: 1000 parts of hydroxyl acrylic resin, 20-40 parts of ethyl methacrylate-2-isocyanate, 55-85 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 15-30 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 10-21 parts of methacrylic silane-treated fumed silica, 3.5-6.8 parts of azobisisobutyronitrile, 0.15-0.45 parts of dibutyltin dilaurate, and 290-455 parts of butyl acetate.

2. The outdoor anti-aging acrylic resin coating according to claim 1, characterized in that, The hydroxyl acrylic resin is a solvent-based hydroxyl acrylic polyol resin, with a hydroxyl content of 4%-5% and a non-volatile content of 65%-75% based on non-volatile matter.

3. The outdoor anti-aging acrylic resin coating according to claim 1, characterized in that, The methacrylic silane-treated fumed silica is a structurally modified fumed silica treated with methacrylic silane, with a silica content of not less than 99.8% and a specific surface area of ​​100-200 m². 2 / g.

4. The outdoor anti-aging acrylic resin coating according to claim 1, characterized in that, The isocyanate group content of the aliphatic hexamethylene diisocyanate trimer curing agent is 18%-21%.

5. A method for preparing an outdoor anti-aging acrylic resin coating according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Hydroxyacrylate resin and butyl acetate are mixed and dehydrated to obtain a dehydrated resin solution; S2. In the presence of dibutyltin dilaurate, ethyl methacrylate-2-isocyanate is reacted with hydroxy acrylic resin in the dehydrated resin solution to obtain a hydroxy acrylic resin intermediate containing a suspended methacrylate double bond. S3. 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, methacrylic silane-treated fumed silica, butyl acetate, and azobisisobutyronitrile are formulated into a first grafting feed solution, and the first grafting feed solution is added to the hydroxyl acrylic resin intermediate containing the suspended methacrylate double bond to carry out the first grafting reaction; S4. 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, methacrylic silane-treated fumed silica, butyl acetate, and azobisisobutyronitrile are prepared to form a second grafting feed solution. The second grafting feed solution is added to the reaction system obtained in step S3 to carry out the second grafting reaction. Butyl acetate and azobisisobutyronitrile are then added to continue the reaction. S5. Add butyl acetate to the system obtained in step S4, stir, cool and filter to obtain the grafted modified hydroxyl acrylic resin component. S6. The grafted modified hydroxyl acrylic resin component is mixed with butyl acetate, propylene glycol methyl ether acetate and aliphatic hexamethylene diisocyanate trimer curing agent to obtain an outdoor anti-aging acrylic resin coating.

6. The method for preparing outdoor anti-aging acrylic resin coating according to claim 5, characterized in that, In step S3, under light-protected conditions, based on 1000 parts of the hydroxy acrylic resin, 15-25 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 12-22 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 1-5 parts of methacrylic silane-treated fumed silica, 30-55 parts of butyl acetate, and 1.5-2.5 parts of azobisisobutyronitrile are added to a dispersion container and dispersed at 500-700 rpm for 25-35 min to obtain the first grafting feed solution; the hydroxy acrylic resin intermediate containing the suspended methacrylate double bond obtained in step S2 is heated to 72-76°C, and the first grafting feed solution is added dropwise over 50-70 min under stirring at 300 rpm and nitrogen protection, and after the dropwise addition is completed, the temperature is maintained at 72-76°C for 20-40 min.

7. The method for preparing outdoor anti-aging acrylic resin coating according to claim 5, characterized in that, In step S4, under light-protected conditions, based on 1000 parts of the hydroxyl acrylic resin, 40-60 parts of 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 3-8 parts of 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 9-16 parts of methacrylic silane-treated fumed silica, 65-95 parts of butyl acetate, and 1.5-2.8 parts of azobisisobutyronitrile are added to a dispersion container and dispersed at 700-900 rpm for 35-45 min to obtain the second grafting feed solution; the reaction system obtained in step S3 is heated to 76-80℃, and the second grafting feed solution is added dropwise over 80-100 min; after the dropwise addition is completed, 15-25 parts of butyl acetate and 0.5-1.5 parts of azobisisobutyronitrile are added, and the reaction is continued at 76-80℃ for 2.5-3.5 h.

8. An outdoor anti-aging acrylic resin coating, characterized in that, The outdoor anti-aging acrylic resin coating is formed by curing the outdoor anti-aging acrylic resin coating prepared by any one of claims 1-4 or by any one of claims 5-7.

9. The outdoor anti-aging acrylic resin coating according to claim 8, characterized in that, The coating is formed on the surface of wood, PVC plastic profiles, or flexible PVC decorative film, and the dry film thickness of the coating is 45±5μm.

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