High-weather-resistance high-fullness polyurethane finish paint and preparation method thereof

Abstract

The invention discloses a high-weather-resistance and high-fullness polyurethane finish paint capable of being used in the field of heavy corrosion prevention, and aims to provide the high-weather-resistance and high-fullness polyurethane finish paint which is high in hardness, high in mechanical strength and excellent in weather resistance and a preparation method of the high-weather-resistance and high-fullness polyurethane finish paint. The invention relates to a high-weather-resistance high-fullness polyurethane finish paint. The double-component polyurethane finish paint comprises a component A and a component B, the weight ratio of the component A to the component B is (5-8): 1; the prepared paint film has the characteristics of excellent aging resistance, high fullness, good decoration and the like.

Description

Technical Field

[0001] The invention relates to a high-weather-resistant and high-fullness polyurethane topcoat which can be used in the field of heavy corrosion protection. Background Art

[0002] Polyurethane coating has excellent adhesion, chemical resistance, decorative and wear resistance. It is a new type of high-end and durable synthetic resin coating. The combination of polyurethane coating and epoxy primer can become a heavy-duty anti-corrosion coating system. Its excellent comprehensive performance makes it widely used in anti-corrosion projects. Among them, acrylic polyurethane topcoat has good weather resistance and decorative properties, but it loses gloss quickly in high temperature and high humidity environments, and it is also easy to lose gloss after wear at room temperature; chemical resistance and adhesion are not as good as polyester polyurethane topcoat; polyester polyurethane topcoat also has the advantages of brightness and fullness, but poor weather resistance and slow drying speed; polyester resin and acrylic resin are mixed to prepare polyurethane topcoat, which combines the excellent properties of both, but there will be compatibility problems, resulting in unstable coating state and the risk of stratification. In actual applications, there are also problems of wear and tear during workpiece handling, which requires excellent wear resistance, weather resistance and high fullness of polyurethane topcoat to avoid such situations. Summary of the invention

[0003] The object of the present invention is to provide a high-weather-resistant and high-fullness polyurethane topcoat with high hardness, high mechanical strength and excellent weather resistance and a preparation method thereof in view of the deficiencies in the prior art.

[0004] A high-weather-resistant and high-fullness polyurethane topcoat: the two-component polyurethane topcoat comprises component A and component B;

[0005]

[0006]

[0007] The sum of the weight parts of the above-mentioned component A is 100 parts, the sum of the weight parts of the component B is 100 parts, and the ratio of component A to component B is 5-8:1 respectively.

[0008] Component A with a solid content of ≥70% and a viscosity of 90-100S (ISO No. 6 cup, 23° C.) is obtained through the process of feeding, stirring, grinding and filtering; component B is obtained by dispersion, and then the final product is obtained by uniformly mixing according to proportion.

[0009] Preferably, the dispersant is one of BYK-110, EFKA-4608 and EFKA-4060;

[0010] Preferably, the pigment is one or more of titanium dioxide, carbon black, red iron oxide, and yellow iron oxide;

[0011] Preferably, the anti-settling agent is one or more of bentonite powder, fumed silica and wax slurry;

[0012] Preferably, the defoamer is one of BYK-077, BYK-057, and EFKA-2018;

[0013] Preferably, the ultraviolet absorber is one of UV531 and UV326;

[0014] Preferably, the light stabilizer is one of Tinuvin 292 and Tinuvin 400;

[0015] Preferably, the leveling agent is one of BYK-310, BYK-306, and EFKA-3033;

[0016] The acrylic acid modified polyester resin described above is prepared from the following components in parts by weight:

[0017] Add 7-15 parts of neopentyl glycol, 5-9 parts of methyl propanediol, 2-6 parts of maleic anhydride, 15-25 parts of adipic acid, 1-3 parts of 1,4-cyclohexanedicarboxylic acid, 1-5 parts of 1,4-cyclohexanedimethanol, 0.05-1 parts of antioxidant and 0.05-1 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a dropping device, a temperature control device and a vacuum device, raise the temperature to 125°C±5°C, keep it warm for 1h, then raise the temperature to 180°C±5°C and keep it warm for 1h, then raise the temperature to 205°C±5°C and keep it warm for 1h, add xylene, raise the temperature to 220°C±5°C and reflux until the acid value is less than 10mgKOH / g Then, add 30-40 parts of solvent and stir evenly, cool to 125℃±5℃, add dropwise a mixed monomer prepared by 2-6 parts of methyl methacrylate, 1-5 parts of isobornyl methacrylate, 1-5 parts of tert-butyl carbonate, 1-5 parts of hydroxypropyl acrylate, 1-5 parts of butyl acrylate, 1-5 parts of butyl methacrylate, 0.01-0.2 parts of initiator, 0.01-0.5 parts of accelerator and 1-5 parts of solvent, the dropping time is 2h-3h, keep warm for 1h after dropping, add 0.01-0.02 parts of initiator, keep warm for 1h, add 0.01-0.02 parts of initiator, keep warm for 1h, cool to room temperature and set aside. The sum of weight parts of each component is 100 parts.

[0018] Preferably, the catalyst is one or more of stannous oxide, stannous octoate, and monobutyltin oxide;

[0019] Preferably, the initiator is one or more of di-tert-amyl peroxide, di-tert-amyl peroxide and tert-butyl perbenzoate;

[0020] Preferably, the accelerator is one of dimethyl sulfoxide and dimethylacetamide;

[0021] Preferably, the mass ratio of the acrylic resin raw material composition to the unsaturated polyester raw material composition is (0.4-0.6):1;

[0022] The above-mentioned organosilicon-modified polyester resin is prepared from the following components in parts by weight:

[0023] Add 7-15 parts of methyl propanediol, 18-25 parts of adipic acid, 18-22 parts of 1,4-cyclohexanedicarboxylic acid, 4-8 parts of 1,4-cyclohexanedimethanol, 0.05-1 parts of antioxidant and 0.05-1 parts of catalyst to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, raise the temperature to 150℃±5℃, keep it warm for 1h, and then raise the temperature to 180℃±5℃ and keep it warm. 1h, then raise the temperature to 205℃±5℃ and keep warm until clear, then cool to 150℃±5℃, add 4-8 parts of trimethylolpropane and 5-8 parts of silicone monomer, then raise the temperature to 205℃±5℃ and keep warm for 1h, add reflux solvent xylene, then raise the temperature to 220℃±5℃, reflux until the acid value is less than 8mgKOH / g, add 30-40 parts of mixed solvent, stir evenly, cool to room temperature and set aside; the total weight of each component is 100 parts.

[0024] Preferably, the antioxidant is one or more of 2,6-di-tert-butylphenol, phosphorous acid, and triphenyl phosphite.

[0025] Preferably, the catalyst is one or more of stannous oxide, stannous octoate, and monobutyltin oxide;

[0026] The silicone resin is a silicone prepolymer Silmer OH Di-50 with dihydroxyl end-capping;

[0027] Preferably, the solvent is one or more of aromatic hydrocarbon solvent, propylene glycol methyl ether acetate, and butyl acetate;

[0028] The silane-modified nano-alumina described above is prepared in the following manner: nano-Al2O3 is placed in a muffle furnace at 400°C and calcined for 3h-5h, cooled to room temperature, and then 70-85 parts of xylene solution are added to (5-10) parts of the calcined nano-Al2O3, ultrasonicated for 40min-50min, and the solution is transferred to a three-necked flask with a stirring device, a dropping device and a temperature control device, and 1-5 parts of a silane coupling agent are slowly added dropwise, and after the dropping is completed, the temperature is raised to 60°C-70°C and the reaction is carried out for 6h-10h; after the reaction is completed, the silane-modified nano-alumina is obtained by cooling, filtering and drying in sequence.

[0029] The silane coupling agent is one or more of methyltrimethoxysilane, methyltriethoxysilane and triethoxyvinylsilane.

[0030] The core part of the present invention is:

[0031] 1. Select silicone resins with hydroxyl groups at both ends and react with organic acids for esterification to form silicone-modified polyester polymers, introduce CO-Si, Si-O-Si, and Si-C bonds on the main chain of the polyester resin, and improve the thermal oxidation stability, weather resistance, scratch resistance, wear resistance, and mechanical properties of the resin. The silicone-modified polyester adopts a two-step method, first synthesizing a linear short-chain polyester, and then adding trimethylolpropane and silicone resin to introduce silicone resin and form a branched structure. High temperature and water in the system are conducive to inhibiting the self-polymerization of silicone resins, and at the same time, there are a large number of exposed carboxylic acid groups that can quickly undergo esterification reactions with silicone resins;

[0032] Second, adopt the method of copolymerization and grafting to first synthesize hydroxyl-type unsaturated polyester, and then carry out free radical polymerization with acrylic monomers. The introduction of acrylic monomers on the side chain effectively inhibits the hydrolysis of the ester group in the polyester macromolecule. The obtained acrylate / polyester copolymer has high gloss, strong adhesion, high fullness, excellent impact resistance, good light and color retention, excellent weather resistance, good hardness and strong corrosion resistance. This method not only solves the compatibility problem of the two, but also combines the excellent performance of both;

[0033] 3. Combining the advantages of silicone resin, polyester resin and acrylic resin, a paint film coating with high fullness, strong scratch resistance and good weather resistance is prepared.

[0034] Fourth, a mixture of di-tert-amyl peroxide and di-tert-amyl peroxide (1.2-1.5):1 is used as an initiator for acrylic resin. The mixed initiator has weak hydrogen abstraction ability, which enables the acrylic resin to effectively form a straight chain, reduce the resin viscosity, and form a high-solid and low-viscosity resin; dimethyl sulfoxide or dimethylacetamide is introduced as a promoter, which has a strong electron-withdrawing ability and can effectively open the double bonds of maleic anhydride to graft acrylic resin, thereby improving the grafting rate of acrylic acid and polyester.

[0035] 5. Nano-Al2O3 is initially activated by high-temperature calcination and then further activated by ultrasound, so that it has a high specific surface area and pore structure, which greatly enhances the bonding area with the silane coupling agent, and the obtained silane-modified nano-Al2O3 has good stability.

[0036] According to the present invention described above, it has the following effects:

[0037] 1. The present invention synthesizes silicone-modified polyester resin and acrylic-modified polyester resin respectively, which solves the problem of poor compatibility between the resins. After being frozen or placed in a 50°C oven for 30 days, there is no stratification or turbidity.

[0038] Second, the present invention selects a silicone resin with hydroxyl groups at both ends to react with an organic acid to synthesize a silicone-modified polyester resin, and introduces a Si-containing related segment in the middle of the polyester main chain, thereby improving the thermal stability, weather resistance, and aging resistance of the resin, reducing the surface energy of the resin, and increasing the smoothness of the coating surface, thereby improving the wear resistance and scratch resistance of the coating. The prepared paint film has a pencil hardness resistance of up to 4H, and a scratch resistance test / grade ≤0;

[0039] 3. The present invention introduces functional acrylic monomers into unsaturated polyesters by free radical copolymerization to form side chains. Tertiary vinyl carbonate has a tertiary carbon structure and isobornyl methacrylate has a larger side group, forming a larger steric hindrance, thereby enhancing the hydrolysis resistance of the resin; hydroxypropyl acrylate has a hydroxyl group, which increases the curing cross-linking site and is conducive to the formation of a network structure during cross-linking and curing; the introduction of acrylic monomers is conducive to improving the fullness, aging resistance, heat resistance, weather resistance and hardness of the topcoat coating; the grafting rate of acrylic monomers and unsaturated polyesters can be increased by adding dimethyl sulfoxide or dimethylacetamide. The impact strength of the obtained paint film is >50cm;

[0040] Fourth, the present invention introduces organic silicon monomers to increase silicon oxygen bonds in the resin, and the silicon oxygen bonds have large bond energy, which makes up for the disadvantage of poor weather resistance of the polyester resin paint film. In addition, the ultraviolet absorber and light stabilizer work together to produce a paint film with excellent aging resistance, high fullness and good decorative properties.

[0041] 5. The present invention modifies the surface of nano-alumina by using a silane coupling agent. On the one hand, the dispersibility of nano-alumina in the coating is improved. On the other hand, the silane coupling agent acts as a "bridge" to improve the connectivity between nano-alumina and the resin. Nano-alumina effectively fills the pores of the paint film and improves the wear resistance, hardness, etc. of the paint film. DETAILED DESCRIPTION

[0042] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the preferred embodiments.

[0043] Example 1

[0044] Step 1: Preparation of acrylic modified polyester resin

[0045] Preparation process: 9.2 parts of neopentyl glycol, 7 parts of methyl propanediol, 4.8 parts of maleic anhydride, 19 parts of adipic acid, 1.5 parts of 1,4-cyclohexanedicarboxylic acid, 4 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, and the temperature was raised to 125°C ± 5°C, kept warm for 1 hour, then raised to 180°C and kept warm for 1 hour, and then raised to 205°C and kept warm for 1 hour, and 2 parts of xylene were added and heated to 220°C and refluxed until the acid value was low. After 10 mg KOH / g, add 20.1 parts of solvent and stir evenly, cool to 125°C, add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 3.8 parts of isobornyl methacrylate, 4 parts of tert-butyl carbonate, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent, the dropping time is 2h, keep warm for 1h after the dropping is completed, add 0.05 parts of initiator, keep warm for reaction for 1h, add 0.05 parts of initiator again, keep warm for 1h, cool to room temperature and set aside.

[0046] Step 2: Preparation of silicone-modified polyester resin

[0047] Preparation process: add 14 parts of methyl propanediol, 18 parts of adipic acid, 22 parts of 1,4-cyclohexanedicarboxylic acid, 8 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.1 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 125°C, keep warm for 1 hour, then heat to 180°C and keep warm for 1 hour, then heat to 205°C and keep warm until clear, cool to 150°C, add 4.4 parts of trimethylolpropane and 5 parts of silicone monomer, heat to 205°C and keep warm for 1 hour, add 2 parts of xylene, heat to 220°C±, reflux until the acid value is less than 8 mgKOH / g, add 26 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0048] Step 3: Prepare two-component polyurethane topcoat

[0049] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 1 hour, and set aside; add 42.5 parts of silicone-modified polyester resin, 42.5 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 600r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1000r / min, mix and stir for 20 minutes, stir well, sand grind to a fineness of less than 25μm, add 0.8 The invention discloses a kind of preparation method of the present invention, wherein the first step is to add 0.5 parts of light stabilizer, 0.8 parts of leveling agent, 0.5 parts of light stabilizer, adjust the speed to 600r / min, disperse evenly, then add the wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for 20 minutes, filter to obtain component A with a solid content ≥70% and a viscosity of 90-100S (ISO No. 6 cup, 23°C); 70 parts of HDI trimer and 30 parts of butyl acetate are dispersed evenly and filtered to obtain component B; components A and B can be used after being stirred and mixed evenly in a ratio of 6:1 during use.

[0050] Embodiment 2:

[0051] Step 1: Preparation of acrylic modified polyester resin

[0052] Preparation process: 7 parts of neopentyl glycol, 9 parts of methyl propanediol, 2 parts of maleic anhydride, 25 parts of adipic acid, 1.5 parts of 1,4-cyclohexanedicarboxylic acid, 3 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, and the temperature was raised to 120°C, kept warm for 1 hour, then raised to 175°C and kept warm for 1 hour, and then raised to 200°C and kept warm for 1 hour, 2 parts of xylene were added, the temperature was raised to 215°C and refluxed until the acid value was less than 10 After adding 20.1 parts of solvent and stirring evenly, cool to 120℃ and add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 2.8 parts of isobornyl methacrylate, 3 parts of vinyl esters, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent. The dropping time is 3h. After the dropping is completed, keep warm for 1h, add 0.05 parts of initiator, keep warm for 1h, add 0.05 parts of initiator, keep warm for 1h, cool to room temperature and set aside.

[0053] Step 2: Preparation of silicone-modified polyester resin

[0054] Preparation process: add 7 parts of methyl propanediol, 25 parts of adipic acid, 18.7 parts of 1,4-cyclohexanedicarboxylic acid, 8 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.1 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 120°C, keep warm for 1 hour, then heat to 175°C and keep warm for 1 hour, then heat to 200°C and keep warm until clear, cool to 145°C, add 8 parts of trimethylolpropane and 5 parts of silicone monomer, heat to 200°C and keep warm for 1 hour, add 2 parts of xylene, heat to 215°C, reflux until the acid value is less than 8 mgKOH / g, add 25.7 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0055] Step 3: Prepare two-component polyurethane topcoat

[0056] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 2 hours, and set aside; add 56.7 parts of silicone-modified polyester resin, 28.3 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 700r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1200r / min, mix and stir for 30 minutes, stir well, sand grind to a fineness of less than 25μm, add 0 .8 parts of leveling agent, 0.8 parts of ultraviolet absorber, 0.5 parts of light stabilizer, adjust the speed to 700r / min, disperse evenly, then add wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for 30 minutes, filter to obtain component A with a solid content ≥70% and a viscosity of 100s (Tu-6 cup, 25°C); 70 parts of HDI trimer and 30 parts of butyl acetate are dispersed evenly and filtered to obtain component B; components A and B can be used after being stirred and mixed evenly at a ratio of 5:1 during use.

[0057] Embodiment 3:

[0058] Step 1: Preparation of acrylic modified polyester resin

[0059] Preparation process: 15 parts of neopentyl glycol, 5 parts of methyl propanediol, 2 parts of maleic anhydride, 18 parts of adipic acid, 1.5 parts of 1,4-cyclohexanedicarboxylic acid, 4 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, the temperature was raised to 130°C, kept warm for 1 hour, then raised to 185°C and kept warm for 1 hour, then raised to 210°C and kept warm for 1 hour, 2 parts of xylene were added, the temperature was raised to 225°C and refluxed until the acid value was less than 10m gKOH / g, add 20.1 parts of solvent and stir evenly, cool to 130℃, add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 3.8 parts of isobornyl methacrylate, 4 parts of vinyl versatate, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent, the adding time is 2.5h, keep warm for 1h after the dropping is completed, add 0.05 parts of initiator, keep warm for 1h, add 0.05 parts of initiator again, keep warm for 1h, cool to room temperature and set aside.

[0060] Step 2: Preparation of silicone-modified polyester resin

[0061] Preparation process: add 12 parts of methyl propanediol, 20 parts of adipic acid, 20 parts of 1,4-cyclohexanedicarboxylic acid, 10 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.1 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 130°C, keep warm for 1 hour, then heat to 185°C and keep warm for 1 hour, then heat to 210°C and keep warm until clear, cool to 155°C, add 4.7 parts of trimethylolpropane and 5 parts of silicone monomer, heat to 210°C and keep warm for 1 hour, add 2 parts of xylene, heat to 225°C, reflux until the acid value is less than 8 mgKOH / g, add 25.7 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0062] Step 3: Prepare two-component polyurethane topcoat

[0063] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 1.5 hours, and set aside; add 63.7 parts of silicone-modified polyester resin, 21.3 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 655r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1100r / min, mix and stir for 25 minutes, stir well, sand grind to a fineness of less than 25μm, add 0.8 0.5 parts of light stabilizer, 0.8 parts of leveling agent, 0.5 parts of light stabilizer, adjust the speed to 660r / min, disperse evenly, then add wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for (20-30) minutes, filter to obtain component A with a solid content of ≥70% and a viscosity of 95S (ISO No. 6 cup, 23°C); 70 parts of HDI trimer and 30 parts of butyl acetate are dispersed evenly and filtered to obtain component B; components A and B can be used after being stirred and mixed evenly at a ratio of 15:1 during use.

[0064] Example 4

[0065] Step 1: Preparation of acrylic modified polyester resin

[0066] Preparation process: 14 parts of neopentyl glycol, 7 parts of methyl propanediol, 4.8 parts of maleic anhydride, 15 parts of adipic acid, 1.0 parts of 1,4-cyclohexanedicarboxylic acid, 4 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, and the temperature was raised to 125℃±5℃, kept warm for 1h, then raised to 180℃±5℃ and kept warm for 1h, then raised to 205℃±5℃ and kept warm for 1h, and then 2 parts of xylene were added and the temperature was raised to 220℃±5℃ and refluxed until the acid value When the temperature is less than 10 mgKOH / g, add 20.0 parts of solvent and stir evenly, cool to 125℃±5℃, add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 4.6 parts of isobornyl methacrylate, 3 parts of tert-butyl carbonate, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent, the dropping time is 2h-3h, keep warm for 1h after dropping, add 0.05 parts of initiator, keep warm for reaction for 1h, add 0.05 parts of initiator, keep warm for 1h, cool to room temperature and set aside.

[0067] Step 2: Preparation of silicone-modified polyester resin

[0068] Preparation process: add 13 parts of methyl propanediol, 18 parts of adipic acid, 20 parts of 1,4-cyclohexanedicarboxylic acid, 8 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.4 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 125°C, keep warm for 1 hour, then heat to 182°C and keep warm for 1 hour, then heat to 208°C and keep warm until clear, cool to 152°C, add 4.4 parts of trimethylolpropane and 8 parts of silicone monomer, heat to 207°C and keep warm for 1 hour, add 2 parts of xylene, heat to 221°C, reflux until the acid value is less than 8 mgKOH / g, add 25.7 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0069] Step 3: Prepare two-component polyurethane topcoat

[0070] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 1h-2h, and set aside; add 42.5 parts of silicone-modified polyester resin, 42.5 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 668r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1050r / min, mix and stir for 23min, stir well, sand grind to a fineness of less than 25μm, and add Add 0.8 parts of leveling agent, 0.8 parts of ultraviolet absorber, and 0.5 parts of light stabilizer, adjust the speed to 654r / min, disperse evenly, then add the wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for 27 minutes, and filter to obtain component A with a solid content of ≥70% and a viscosity of 93 (ISO No. 6 cup, 23°C); evenly disperse 70 parts of HDI trimer and 30 parts of butyl acetate, and filter to obtain component B; during use, components A and B can be used after being stirred and mixed evenly at a ratio of 8:1.

[0071] Embodiment 5:

[0072] Step 1: Preparation of acrylic modified polyester resin

[0073] Preparation process: 9 parts of neopentyl glycol, 7.2 parts of methyl propanediol, 4.8 parts of maleic anhydride, 19 parts of adipic acid, 1.5 parts of 1,4-cyclohexanedicarboxylic acid, 4 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, and the temperature was raised to 122°C, kept warm for 1 hour, then raised to 175°C and kept warm for 1 hour, and then raised to 207°C and kept warm for 1 hour, 2 parts of xylene were added, the temperature was raised to 195°C and refluxed until the acid value was less than 1 0mgKOH / g, add 20.1 parts of solvent and stir evenly, cool to 122℃, add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 3.8 parts of isobornyl methacrylate, 4 parts of tert-butyl carbonate, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent, the dropping time is 2.3h, keep warm for 1h after dropping, add 0.05 parts of initiator, keep warm for 1h, add 0.05 parts of initiator, keep warm for 1h, cool to room temperature and set aside.

[0074] Step 2: Preparation of silicone-modified polyester resin

[0075] Preparation process: add 13 parts of methyl propanediol, 18 parts of adipic acid, 20 parts of 1,4-cyclohexanedicarboxylic acid, 8 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.4 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 124°C, keep warm for 1 hour, then heat to 176°C and keep warm for 1 hour, then heat to 207°C and keep warm until clear, cool to 145°C, add 4.4 parts of trimethylolpropane and 8 parts of silicone monomer, heat to 206°C and keep warm for 1 hour, add 2 parts of xylene, heat to 223°C, reflux until the acid value is less than 8 mgKOH / g, add 25.7 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0076] Step 3: Prepare two-component polyurethane topcoat

[0077] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 1.2 hours, and set aside; add 56.7 parts of silicone-modified polyester resin, 28.3 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 650r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1080r / min, mix and stir for 22 minutes, stir well, sand grind to a fineness of less than 25μm, and add 0.8 parts of leveling agent, 0.8 parts of ultraviolet absorber, 0.5 parts of light stabilizer, adjust the speed to 654r / min, disperse evenly, then add wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for 22 minutes, filter to obtain component A with a solid content of ≥70% and a viscosity of 93S (ISO No. 6 cup, 23°C); 70 parts of HDI trimer and 30 parts of butyl acetate are dispersed evenly and filtered to obtain component B; components A and B can be used after being stirred and mixed evenly in a ratio of 6:1 during use.

[0078] Embodiment 6:

[0079] Step 1: Preparation of acrylic modified polyester resin

[0080] Preparation process: 9.2 parts of neopentyl glycol, 7 parts of methyl propanediol, 4.8 parts of maleic anhydride, 19 parts of adipic acid, 1.5 parts of 1,4-cyclohexanedicarboxylic acid, 4 parts of 1,4-cyclohexanedimethanol, 0.1 parts of antioxidant and 0.4 parts of catalyst were added to a reactor equipped with a stirring device, a reflux condensing device, a dropping device, a temperature control device and a vacuum device, and the temperature was raised to 125°C, kept warm for 1 hour, then raised to 180°C and kept warm for 1 hour, and then raised to 205°C and kept warm for 1 hour, 2 parts of xylene were added, the temperature was raised to 223°C and refluxed until the acid value was less than After 10mgKOH / g, add 20.1 parts of solvent and stir evenly, cool to 127℃, add dropwise a mixed monomer prepared by 5 parts of methyl methacrylate, 3.8 parts of isobornyl methacrylate, 4 parts of tert-butyl carbonate, 3 parts of hydroxypropyl acrylate, 3 parts of butyl acrylate, 3.5 parts of butyl methacrylate, 0.2 parts of initiator, 0.3 parts of accelerator and 9 parts of solvent, the dropping time is 2h, keep warm for 1h after dropping, add 0.05 parts of initiator, keep warm for 1h, add 0.05 parts of initiator, keep warm for 1h, cool to room temperature and set aside.

[0081] Step 2: Preparation of silicone-modified polyester resin

[0082] Preparation process: add 14 parts of methyl propanediol, 18 parts of adipic acid, 20 parts of 1,4-cyclohexanedicarboxylic acid, 7 parts of 1,4-cyclohexanedimethanol, 0.5 parts of antioxidant and 0.4 parts of catalyst to a reactor equipped with a stirring device, a reflux condensing device, a temperature control device and a vacuum device, heat to 125°C, keep warm for 1 hour, then heat to 180°C and keep warm for 1 hour, then heat to 205°C and keep warm until clear, cool to 150°C, add 4.4 parts of trimethylolpropane and 8 parts of silicone monomer, heat to 205°C and keep warm for 1 hour, add 2 parts of xylene, heat to 220°C, reflux until the acid value is less than 8 mgKOH / g, add 25.7 parts of mixed solvent, stir evenly, cool to room temperature and set aside;

[0083] Step 3: Prepare two-component polyurethane topcoat

[0084] Preparation process: put 0.5 parts of silane-modified nano-alumina and 1 part of butyl acetate into the barrel, soak and moisten for 2 hours, and set aside; add 63.7 parts of silicone-modified polyester resin, 21.3 parts of acrylic acid-modified polyester resin, 1 part of dispersant, and 0.5 parts of defoamer into the barrel, adjust the speed to 700r / min, stir evenly, then slowly add 8 parts of pigment and 1 part of anti-settling agent, adjust the speed to 1200r / min, mix and stir for 20 minutes, stir evenly, sand grind to a fineness of less than 25μm, add 0. 8 parts of leveling agent, 0.8 parts of ultraviolet absorber, 0.5 parts of light stabilizer, adjust the speed to 667r / min, disperse evenly, then add wetted silane-modified nano-alumina and 0.9 parts of butyl acetate, disperse for 25 minutes, filter to obtain component A with a solid content ≥70% and a viscosity of 98S (ISO No. 6 cup, 23°C); 70 parts of HDI trimer and 30 parts of butyl acetate are dispersed evenly and filtered to obtain component B; components A and B can be used after being stirred and mixed evenly at a ratio of 13:1 during use.

[0085] The above Examples 1-6 were coated with a suitable wire rod to prepare test panels, and performance tests were performed after the test panels were completely dry. The results are as follows.

[0086]

[0087]

[0088]

[0089] As long as the ratios between the components meet the requirements of the present invention, the performance of the resulting formula meets the requirements, no more examples will be given herein.

Claims

1. A highly weather-resistant and high-fullness polyurethane topcoat, characterized in that: The two-component polyurethane topcoat comprises component A and component B; the components are respectively Component A: Component B: HDI trimer 60-80 parts 20-40 parts of butyl acetate The sum of the weight parts of the above-mentioned component A is 100 parts, the sum of the weight parts of the component B is 100 parts, and the weight ratio of component A to component B is 5-8:1 respectively.

2. The highly weather-resistant and high-fullness polyurethane topcoat according to claim 1, characterized in that: The acrylic acid modified polyester resin is prepared from the following components in parts by weight: In a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, 7-15 parts of neopentyl glycol, 5-9 parts of methyl propanediol, 2-6 parts of maleic anhydride, 15-25 parts of adipic acid, 1-3 parts of 1,4-cyclohexanedicarboxylic acid, 1-5 parts of 1,4-cyclohexanedimethanol, 0.05-1 parts of antioxidant and 0.05-1 parts of catalyst were added, the temperature was raised to 125°C ± 5°C, kept warm for 1h, then raised to 180°C ± 5°C and kept warm for 1h, then raised to 205°C ± 5°C and kept warm for 1h, then xylene was added, the temperature was raised to 220°C ± 5°C, refluxed until the acid value was less than 10mgKOH / g, and 30- Stir 40 parts of solvent evenly, cool to 125℃±5℃, add dropwise a mixed monomer prepared by 2-6 parts of methyl methacrylate, 1-5 parts of isobornyl methacrylate, 1-5 parts of vinyl versatate, 1-5 parts of hydroxypropyl acrylate, 1-5 parts of butyl acrylate, 1-5 parts of butyl methacrylate, 0.01-0.2 parts of initiator, 0.01-0.5 parts of accelerator and 1-5 parts of solvent, the dropping time is 2h-3h, keep warm for 1h after dropping, add 0.01-0.02 parts of initiator, keep warm for reaction for 1h, add 0.01-0.02 parts of initiator again, keep warm for 1h, cool to room temperature and set aside; the sum of weight parts of each component is 100 parts.

3. The highly weather-resistant and high-fullness polyurethane topcoat according to claim 1, characterized in that: The organosilicon-modified polyester resin is prepared from the following components in parts by weight: Add 7-15 parts of methyl propanediol, 18-25 parts of adipic acid, 18-22 parts of 1,4-cyclohexanedicarboxylic acid, 4-8 parts of 1,4-cyclohexanedimethanol, 0.05-1 parts of antioxidant and 0.05-1 parts of catalyst to a reactor equipped with a stirring device, a reflux condenser, a dropping device, a temperature control device and a vacuum device, raise the temperature to 150℃±5℃, keep it warm for 1h, and then raise the temperature to 180℃±5℃ and keep it warm. 1h, then raise the temperature to 205℃±5℃ and keep warm until clear, then cool to 150℃±5℃, add 4-8 parts of trimethylolpropane and 5-8 parts of silicone monomer, then raise the temperature to 205℃±5℃ and keep warm for 1h, add reflux solvent xylene, then raise the temperature to 220℃±5℃, reflux until the acid value is less than 8mgKOH / g, add 30-40 parts of mixed solvent, stir evenly, cool to room temperature and set aside; the total weight of each component is 100 parts.

4. The highly weather-resistant and high-fullness polyurethane topcoat according to claim 1, characterized in that: The silane-modified nano-alumina described above is prepared in the following manner: nano-Al2O3 is placed in a muffle furnace at 400°C and calcined for 3h-5h, cooled to room temperature, and then 70-85 parts of xylene solution are added to (5-10) parts of the calcined nano-Al2O3, ultrasonicated for 40min-50min, and the solution is transferred to a three-necked flask with a stirring device, a dropping device and a temperature control device, and 1-5 parts of a silane coupling agent are slowly added dropwise, and after the dropping is completed, the temperature is raised to 60°C-70°C and the reaction is carried out for 6h-10h; after the reaction is completed, the silane-modified nano-alumina is obtained by cooling, filtering and drying in sequence.

5. A method for preparing the above-mentioned high-weatherability and high-fullness polyurethane topcoat: put silane-modified nano-alumina and butyl acetate into a barrel, soak and moisten for 2 hours, and set aside; add silicone-modified polyester resin, acrylic acid-modified polyester resin, dispersant, and defoamer into the barrel, adjust the speed to 700r / min, stir evenly, slowly add pigment and anti-settling agent, adjust the speed to 1200r / min, mix and stir for 30 minutes, stir well and sand grind to a fineness of less than 25μm, add leveling agent, ultraviolet absorber, and light stabilizer, adjust the speed to 700r / min, disperse evenly, then add the wetted silane-modified nano-alumina and butyl acetate, disperse for 30 minutes, and filter to obtain component A with a solid content of ≥70% and a viscosity of 100s (Tu-6 cup, 25°C); disperse HDI trimer and butyl acetate evenly in proportion and filter to obtain component B; components A and B can be used after being stirred and mixed evenly at a ratio of 5-8:1 during use.

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