High-adhesion high-weather-resistance varnish coating and preparation method thereof

Abstract

The present application relates to the technical field of paint, and discloses a varnish paint with high adhesion and high weather resistance and a preparation method thereof.The preparation steps are as follows: S1: taking polyhydroxy additive, ethylene glycol, neopentyl glycol, isophthalic acid, uniformly stirring under nitrogen protection, adding dibutyl tin laurate, keeping warm for 1-2 h, increasing temperature to 200-220 DEG C, keeping warm until the acid value is less than or equal to 100 mg / g, and then decreasing temperature to 80-85 DEG C; adding neopentyl glycol and maleic anhydride, increasing temperature to 160-170 DEG C, keeping warm for 1-2 h, increasing temperature to 200-220 DEG C again, keeping warm until the acid value is less than or equal to 5 mg / g, and then obtaining polyester; S2: taking polyester, acrylic resin, defoaming agent, dispersant, leveling agent and anti-sagging aid, mixing uniformly, adding modified silicon dioxide, and uniformly stirring to obtain component A; mixing cobalt isooctoate and methyl ethyl ketone peroxide to obtain component B; mixing component A and component B, adjusting viscosity, and obtaining the varnish paint.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paint technology, and discloses a varnish coating with high adhesion and high weather resistance and a preparation method thereof. BACKGROUND

[0002] With the continuous development of the paint industry, polyester varnish is widely used in various fields due to its excellent hardness, gloss and wear resistance. The polyester varnish for automotive interior and exterior decoration often uses vertical spraying process, which has the problem of easy sagging. Sagging refers to the phenomenon that the lower part of the wet film becomes thick and the upper part becomes thin after the coating is applied on the vertical surface due to the influence of gravity, resulting in performance degradation.

[0003] At the same time, the existing polyester varnish still has some deficiencies in actual application, especially in adhesion and weather resistance. The paint film has poor adhesion and is easy to fall off under impact. The insufficient weather resistance leads to problems such as discoloration, powdering and loss of gloss of the paint film, which seriously affects the service life. In summary, it is of great significance to study a varnish coating with no sagging, high adhesion and high weather resistance and a preparation method thereof. SUMMARY

[0004] The present application relates to the field of paint technology, and discloses a varnish coating with high adhesion and high weather resistance and a preparation method thereof.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme: a preparation method of a varnish coating with high adhesion and high weather resistance, comprising the following steps: S1: taking triallylphenylsilane, adding ethanol and stirring uniformly, adding weather-resistant antioxidant, mercapto-polyethylene glycol-hydroxyl and 1-thioglycerol, stirring uniformly, adding a photoinitiator, stirring under ultraviolet light for 5-10 min, removing the solvent, and obtaining a polyhydroxy additive;

[0006] S2: taking the polyhydroxy additive, ethylene glycol, neopentyl glycol and isophthalic acid, heating to 160-170 DEG C under nitrogen protection, stirring uniformly, adding dibutyltin laurate, and keeping warm for 1-2 h; when the acid value (calculated by KOH) is less than or equal to 100 mg / g, the temperature is lowered to 80-85 DEG C; neopentyl glycol and maleic anhydride are added, heated to 160-170 DEG C and kept warm for 1-2 h, then heated to 200-220 DEG C and kept warm until the acid value is less than or equal to 5 mg / g, and a polyester is obtained;

[0007] S3: taking the polyester, acrylic resin, defoaming agent, dispersant, leveling agent, anti-sagging additive (Japan Cabot M-5), mixing uniformly, adding modified silica, stirring uniformly, obtaining component A; taking cobalt isooctanoate and methyl ethyl ketone peroxide mixture, obtaining component B; mixing component A and component B, adjusting the viscosity as needed, and obtaining a varnish coating.

[0008] More preferably, the polyhydroxyl additive comprises the following raw materials in parts by mass: 2-2.5 parts of triallylphenylsilane, 50-150 parts of ethanol, 3-3.5 parts of weather-resistant antioxidant, 8-10 parts of mercapto-polyethylene glycol-hydroxyl, 1-1.5 parts of 1-thioglycerol, and 0.01-0.015 parts of photoinitiator.

[0009] More preferably, the polyester comprises the following raw materials in parts by mass: 20-30 parts of polyhydroxyl additive, 2-3 parts of ethylene glycol, 30-50 parts of neopentyl glycol, 20-25 parts of isophthalic acid, and 0.1-0.2 parts of dibutyltin laurate, and 15-25 parts of maleic anhydride.

[0010] More preferably, the polyester is prepared as follows: 20-30 parts of polyhydroxyl additive, 2-3 parts of ethylene glycol, 15-20 parts of neopentyl glycol, and 20-25 parts of isophthalic acid are heated to 160-170°C under nitrogen protection, stirred uniformly, 0.1-0.2 parts of dibutyltin laurate is added, and heated to 200-220°C for 1-2 hours, until the acid value (in terms of KOH) is less than 100 mg / g, and then cooled to 80-85°C; 18-25 parts of neopentyl glycol and 15-25 parts of maleic anhydride are added, heated to 160-170°C for 1-2 hours, and then heated to 200-220°C, until the acid value is ≤5 mg / g, to obtain the polyester.

[0011] More preferably, the component A comprises the following raw materials in parts by mass: 40-50 parts of polyester, 6-10 parts of acrylic resin, 0.1-0.2 parts of defoaming agent, 0.3-0.5 parts of dispersant, 0.3-0.5 parts of leveling agent, 0.1-0.2 parts of anti-sagging aid, and 10-15 parts of modified silica; the component B comprises cobalt isooctanoate and methyl ethyl ketone peroxide in a mass ratio of 1:(2-3); and the mass ratio of the component A to the component B is 100:(1-2).

[0012] More preferably, the weather-resistant antioxidant is prepared by the following steps: 1-hydroxybenzotriazole, 5-chlorobenzimidazole-2-thiol, sodium carbonate, and tetrahydrofuran are mixed uniformly, stirred at 50-60°C for 4-6 hours, and then the solvent and unreacted substances are removed to obtain the weather-resistant antioxidant.

[0013] More preferably, the weather-resistant antioxidant comprises the following raw materials in parts by mass: 10-15 parts of 1-hydroxybenzotriazole, 16-20 parts of 5-chlorobenzimidazole-2-thiol, 8-12 parts of sodium carbonate, and 60-80 parts of tetrahydrofuran.

[0014] More preferably, the preparation of the modified silica comprises the following steps: taking nano-silica, chloromethyl trimethoxysilane, adding to 50wt% ethanol aqueous solution, adjusting pH to 5-6, stirring at 50-60 DEG C for 6-8h, filtering, washing and drying the solid to obtain chloro-containing silica; taking the chloro-containing silica, adding to water, adding allyl hydroxyethyl ether, hydroxyethyl acrylate, stirring uniformly, stirring at 25-30 DEG C for 8-12h, filtering, washing and drying the solid to obtain the modified silica.

[0015] More preferably, the chloro-containing silica comprises the following raw materials in parts by mass: 10-15 parts of nano-silica, 1-2 parts of chloromethyl trimethoxysilane; the modified silica comprises the following raw materials in parts by mass: 10-15 parts of chloro-containing silica, 0.5-1 parts of allyl hydroxyethyl ether, 1-2 parts of hydroxyethyl acrylate.

[0016] Compared with the prior art, the application has the beneficial effects that: the polyester prepared by the application contains a polyhydroxy additive, and the preparation steps are as follows: 1-hydroxybenzotriazole with ultraviolet resistance is compounded with 5-chlorobenzimidazole-2-thiol with anti-aging performance to obtain a thiol-containing weather-resistant anti-aging agent; then, using triallylphenylsilane as a matrix and using its double bond structure, the weather-resistant anti-aging agent, thiol-polyethylene glycol-hydroxyl and 1-thioglycerol are grafted; triallylphenylsilane itself has good heat resistance and contains multiple active groups, the introduction of thiol-polyethylene glycol-hydroxyl improves the overall polarity and enhances the adhesion of the coating, and the introduction of 1-thioglycerol introduces multiple active hydroxyl groups, which is helpful for the next reaction; the addition amount of the above substances needs to be controlled to ensure that the polyhydroxy additive prepared contains multiple hydroxyl groups that can participate in the next reaction and has sufficient weather resistance, anti-aging performance and adhesion; the method ensures the uniform dispersion of the functional compounds in the varnish matrix and reduces the migration problem, thereby improving the adhesion and service life of the varnish.

[0017] The addition amount of the polyhydroxy additive in the polyester also needs to be controlled, and the addition amount determines the branching degree of the polyester; the improvement of the branching degree helps to improve the mechanical properties, weather resistance, flexibility and film-forming properties, but due to the large molecular weight, if too much is introduced, it may affect polymerization or lead to poor dispersibility, thereby leading to performance degradation; and too many benzene rings introduced will cause the varnish to yellow easily.

[0018] The present application adds leveling agent and anti-sagging assistant in varnish, and introduces acrylic resin to further improve adhesion, but the compatibility of acrylic resin and polyester is poor, which affects the leveling performance of the system, therefore, the present application controls the amount of acrylic resin, and introduces modified silica to improve the above problems: first, prepare chlorine-containing silica, then introduce allyl hydroxyethyl ether and hydroxyethyl acrylate to obtain modified silica; wherein, hydroxyethyl acrylate has good compatibility with acrylic resin, allyl hydroxyethyl ether has similar segments in polyester, and the compatibility is improved, therefore, the addition of the modified silica helps to improve the compatibility between acrylic resin and polyester, and allyl hydroxyethyl ether and hydroxyethyl acrylate can be used as active diluent monomers, which can reduce the viscosity and improve the performance of varnish film on the one hand, and improve the dispersibility of silica in varnish on the other hand.

[0019] In summary, through the above process, varnish coating with good anti-sagging property, good weather resistance and good adhesion can be prepared. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] It should be noted that there is no special limitation on the purchase manufacturer of all raw materials involved in the present application, which exemplarily includes: ethanol (CAS: 64-17-5); acrylic resin (M.W~3000, Aldrich); defoaming agent (TOYNOLDY-80 defoaming agent, TL-110D, Jihewangchang); anti-sagging assistant (Japan Cabot M-5); allyl hydroxyethyl ether (CAS: 111-45-5); hydroxyethyl acrylate (CAS: 818-61-1); 1-hydroxybenzotriazole (CAS: 2592-95-2); 5-chlorobenzimidazole-2-thiol (CAS: 25369-78-2); triallylphenylsilane (CAS: 2633-57-0); mercapto-polyethylene glycol-hydroxyl (Mn~1000, Tansh); 1-thioglycerol (CAS: 96-27-5); dispersant (coating dispersant CP88, Linyi Guolihua Chemical Co., Ltd.); leveling agent (TL-J65A, Jihewangchang); cobalt isooctoate (CAS: 136-52-7); methyl ethyl ketone peroxide (CAS: 1338-23-4); nano-silica (ML-SiO2-N12, Manli); chloromethyltrimethoxysilane (CAS: 5926-26-1); sodium carbonate (anhydrous sodium carbonate, CAS: 497-19-8); photoinitiator (photoinitiator 1173, CAS: 7473-98-5);

[0022] The following are all mass parts, mass ratios, unless otherwise specified.

[0023] Example 1: S1: Take 10 parts of nano-silicon dioxide, 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50wt% ethanol aqueous solution, adjust pH to 5, stir at 60℃ for 6h, filter, wash and dry the solid to obtain chloro-containing silicon dioxide;

[0024] S2: Take 12 parts of chloro-containing silicon dioxide, add to 100 parts of water, add 0.8 parts of allyl hydroxyethyl ether, 1.5 parts of hydroxyethyl acrylate, stir uniformly, stir at 25℃ for 12h, filter, wash and dry the solid to obtain modified silicon dioxide;

[0025] S3: Mix 13 parts of 1-hydroxybenzotriazole, 18 parts of 5-chlorobenzimidazole-2-thiol, 10 parts of sodium carbonate, 80 parts of tetrahydrofuran uniformly, stir at 60℃ for 6h, remove the solvent to obtain a weather-resistant antioxidant;

[0026] S4: Take 2.5 parts of triallylphenylsilane, add to 60 parts of ethanol and stir uniformly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, 1.5 parts of 1-thioglycerol, stir uniformly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 6min, remove the solvent to obtain a polyhydroxy additive;

[0027] S5: Take 28 parts of polyhydroxy additive, 2 parts of ethylene glycol, 16 parts of neopentyl glycol, 25 parts of isophthalic acid, heat to 160℃ under nitrogen protection, stir uniformly, add 0.1 parts of dibutyltin laurate, heat for 2h, heat to 220℃ until the acid value is 100mg / g, then cool to 85℃; add 20 parts of neopentyl glycol and 20 parts of maleic anhydride, heat to 160℃ for 1h, then heat to 220℃ until the acid value is 5mg / g to obtain a polyester;

[0028] S6: Take 45 parts of polyester, 8 parts of acrylic resin, 0.1 parts of defoaming agent, 0.3 parts of dispersant, 0.3 parts of leveling agent, 0.1 parts of anti-sagging aid, mix uniformly, add 12 parts of modified silicon dioxide, stir uniformly to obtain component A; take mass ratio of 1:2 of cobalt isooctoate and methyl ethyl ketone peroxide, mix to obtain component B; mix component A and component B according to mass ratio of 100:2 to obtain a clear paint.

[0029] Example 2: S1: Take 10 parts of nano-silicon dioxide, 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50wt% ethanol aqueous solution, adjust pH to 5, stir at 60℃ for 6h, filter, wash and dry the solid to obtain chloro-containing silicon dioxide;

[0030] S2: Take 10 parts of chlorinated silica dioxide, add 100 parts of water, add 0.5 parts of allyl hydroxyethyl ether, 2 parts of hydroxyethyl acrylate, stir uniformly, stir at 25℃ for 12h, filter, wash and dry the solid, obtain modified silica dioxide;

[0031] S3: Mix 10 parts of 1-hydroxybenzotriazole, 16 parts of 5-chlorobenzimidazole-2-thiol, 8 parts of sodium carbonate, 80 parts of tetrahydrofuran uniformly, stir at 60℃ for 6h, remove the solvent, obtain weather-resistant antioxidant;

[0032] S4: Take 2 parts of triallylphenylsilane, add 60 parts of ethanol and stir uniformly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, 1 part of 1-thioglycerol, stir uniformly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 5min, remove the solvent, obtain polyhydroxy additive;

[0033] S5: Take 20 parts of polyhydroxy additive, 2 parts of ethylene glycol, 15 parts of neopentyl glycol, 20 parts of isophthalic acid, heat to 160℃ under nitrogen protection, stir uniformly, add 0.1 parts of dibutyl tin laurate, heat for 2h, heat to 220℃, when the acid value is 100mg / g, cool to 85℃; Add 18 parts of neopentyl glycol, 18 parts of maleic anhydride, heat to 160℃ for 1h, then heat to 220℃ until the acid value is 5mg / g, obtain polyester;

[0034] S6: Take 40 parts of polyester, 6 parts of acrylic resin, 0.1 parts of defoaming agent, 0.3 parts of dispersant, 0.3 parts of leveling agent, 0.1 parts of anti-sagging aid, mix uniformly, add 10 parts of modified silica dioxide, stir uniformly, obtain component A; Take mass ratio of 1:2 of cobalt isooctanoate and methyl ethyl ketone peroxide, mix, obtain component B; Mix component A and component B according to mass ratio of 100:2, obtain clear paint.

[0035] Example 3: S1: Take 10 parts of nano-silica, 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50wt% ethanol aqueous solution, adjust pH to 5, stir at 60℃ for 6h, filter, wash and dry the solid, obtain chlorinated silica dioxide;

[0036] S2: Take 15 parts of chlorinated silica dioxide, add 100 parts of water, add 1 part of allyl hydroxyethyl ether, 2 parts of hydroxyethyl acrylate, stir uniformly, stir at 25℃ for 12h, filter, wash and dry the solid, obtain modified silica dioxide;

[0037] S3: Mix 15 parts of 1-hydroxybenzotriazole, 20 parts of 5-chlorobenzimidazole-2-thiol, 12 parts of sodium carbonate, 80 parts of tetrahydrofuran uniformly, stir at 60℃ for 6h, remove the solvent, obtain weather-resistant antioxidant;

[0038] S4: Take 2.5 parts of triallyl phenyl silane, add 60 parts of ethanol and stir evenly, add 3.5 parts of weather-resistant antioxidant, 10 parts of mercapto-polyethylene glycol-hydroxyl, 1.5 parts of 1-thioglycerol, stir evenly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 10 min, remove the solvent, and obtain the polyhydroxy additive;

[0039] S5: Take 30 parts of polyhydroxy additive, 3 parts of ethylene glycol, 20 parts of neopentyl glycol, 25 parts of isophthalic acid, and stir evenly under nitrogen protection at 160°C. Add 0.1 parts of dibutyl tin laurate, and heat for 2 h. When the acid value is 100 mg / g, heat to 220°C, and then cool to 85°C. Add 25 parts of neopentyl glycol and 25 parts of maleic anhydride, heat to 160°C for 1 h, and then heat to 220°C until the acid value is 5 mg / g. The polyester is obtained.

[0040] S6: Take 50 parts of polyester, 10 parts of acrylic resin, 0.1 parts of defoaming agent, 0.3 parts of dispersant, 0.3 parts of leveling agent, and 0.1 parts of anti-sagging aid, mix evenly, add 15 parts of modified silica, and stir evenly to obtain component A. Take mass ratio of 1:2 of cobalt isooctanoate and methyl ethyl ketone peroxide, mix to obtain component B. Mix component A and component B according to the mass ratio of 100:2 to obtain the clear paint.

[0041] Comparative Example 1 (change the amount of raw materials in the polyester, and the rest of the method steps are consistent with Example 1): S1: Take 10 parts of nano-silica and 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50 wt% ethanol aqueous solution, adjust the pH to 5, stir at 60°C for 6 h, filter, wash and dry the solid to obtain chloro-containing silica;

[0042] S2: Take 12 parts of chloro-containing silica, add to 100 parts of water, add 0.8 parts of allyl hydroxyethyl ether and 1.5 parts of hydroxyethyl acrylate, stir evenly, and stir at 25°C for 12 h. Filter, wash and dry the solid to obtain modified silica;

[0043] S3: Mix 13 parts of 1-hydroxybenzotriazole, 18 parts of 5-chlorobenzimidazole-2-thiol, 10 parts of sodium carbonate, and 80 parts of tetrahydrofuran evenly, stir at 60°C for 6 h, and remove the solvent to obtain the weather-resistant antioxidant;

[0044] S4: Take 2.5 parts of triallyl phenyl silane, add 60 parts of ethanol and stir evenly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, and 1.5 parts of 1-thioglycerol, stir evenly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 6 min, remove the solvent, and obtain the polyhydroxy additive;

[0045] S5: Take 40 parts of polyhydroxy additive, 1 part of ethylene glycol, 16 parts of neopentyl glycol, 25 parts of isophthalic acid, under nitrogen protection, heat to 160°C, stir evenly, add 0.1 part of dibutyl tin laurate, heat for 2h, heat to 220°C, when the acid value is 100mg / g, cool to 85°C; add 20 parts of neopentyl glycol, 20 parts of maleic anhydride, heat to 160°C for 1h, then heat to 220°C, heat until the acid value is 5mg / g, to get polyester;

[0046] S6: Take 45 parts of polyester, 8 parts of acrylic resin, 0.1 part of defoaming agent, 0.3 part of dispersant, 0.3 part of leveling agent, 0.1 part of anti-sagging aid, mix evenly, add 12 parts of modified silica, stir evenly, get component A; take mass ratio 1:2 of cobalt isooctanoate, methyl ethyl ketone peroxide, mix, get component B; mix component A, component B according to mass ratio 100:2, get clear paint.

[0047] Comparative example 2 (change the amount of raw materials in polyester, the rest of the method steps are consistent with example 1): S1: take 10 parts of nano silica, 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50wt% ethanol aqueous solution, adjust pH to 5, stir at 60°C for 6h, filter, wash and dry the solid to get chloro-containing silica;

[0048] S2: take 12 parts of chloro-containing silica, add to 100 parts of water, add 0.8 parts of allyl hydroxyethyl ether, 1.5 parts of hydroxyethyl acrylate, stir evenly, stir at 25°C for 12h, filter, wash and dry the solid to get modified silica;

[0049] S3: mix 13 parts of 1-hydroxybenzotriazole, 18 parts of 5-chlorobenzimidazole-2-thiol, 10 parts of sodium carbonate, 80 parts of tetrahydrofuran evenly, stir at 60°C for 6h, remove the solvent to get weather-resistant antioxidant;

[0050] S4: take 2.5 parts of triallyl phenyl silane, add to 60 parts of ethanol and stir evenly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, 1.5 parts of 1-thioglycerol, stir evenly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 6min, remove the solvent to get polyhydroxy additive;

[0051] S5: take 10 parts of polyhydroxy additive, 4 parts of ethylene glycol, 16 parts of neopentyl glycol, 25 parts of isophthalic acid, under nitrogen protection, heat to 160°C, stir evenly, add 0.1 part of dibutyl tin laurate, heat for 2h, heat to 220°C, when the acid value is 100mg / g, cool to 85°C; add 20 parts of neopentyl glycol, 20 parts of maleic anhydride, heat to 160°C for 1h, then heat to 220°C, heat until the acid value is 5mg / g, to get polyester;

[0052] S6: Take 45 parts of polyester, 8 parts of acrylic resin, 0.1 part of defoaming agent, 0.3 part of dispersing agent, 0.3 part of leveling agent, 0.1 part of anti-sagging aid, mix uniformly, add 12 parts of modified silica, stir uniformly, get component A; take mass ratio 1:2 of cobalt isooctanoate, methyl ethyl ketone peroxide, mix, get component B; mix component A, component B according to mass ratio 100:2, get varnish coating.

[0053] Comparative Example 3 (change the preparation method of modified silica, the rest of the method steps are consistent with Example 1): S1: take 10 parts of nano silica, add 0.8 parts of allyl hydroxyethyl ether, 1.5 parts of hydroxyethyl acrylate, stir uniformly, get modified silica;

[0054] S2: mix 13 parts of 1-hydroxybenzotriazole, 18 parts of 5-chlorobenzimidazole-2-thiol, 10 parts of sodium carbonate, 80 parts of tetrahydrofuran uniformly, stir at 60℃ for 6h, remove the solvent, get weather-resistant antioxidant;

[0055] S3: take 2.5 parts of triallyl phenyl silane, add 60 parts of ethanol and stir uniformly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, 1.5 parts of 1-thioglycerol, stir uniformly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 6min, remove the solvent, get polyhydroxy additive;

[0056] S4: take 28 parts of polyhydroxy additive, 2 parts of ethylene glycol, 16 parts of neopentyl glycol, 25 parts of isophthalic acid, under nitrogen protection, heat to 160℃, stir uniformly, add 0.1 parts of dibutyl tin laurate, heat for 2h, heat to 220℃, when the acid value is 100mg / g, cool to 85℃; add 20 parts of neopentyl glycol, 20 parts of maleic anhydride, heat to 160℃ for 1h, then heat to 220℃, when the acid value is 5mg / g, get polyester;

[0057] S5: take 45 parts of polyester, 8 parts of acrylic resin, 0.1 part of defoaming agent, 0.3 part of dispersing agent, 0.3 part of leveling agent, 0.1 part of anti-sagging aid, mix uniformly, add 12 parts of modified silica, stir uniformly, get component A; take mass ratio 1:2 of cobalt isooctanoate, methyl ethyl ketone peroxide, mix, get component B; mix component A, component B according to mass ratio 100:2, get varnish coating.

[0058] Comparative Example 4 (change the amount of raw materials in component A, the rest of the method steps are consistent with Example 1): S1: take 10 parts of nano silica, 2 parts of chloromethyl trimethoxysilane, add to 100 parts of 50wt% ethanol aqueous solution, adjust pH to 5, stir at 60℃ for 6h, filter, wash and dry the solid, get chloro-containing silica;

[0059] S2: Take 12 parts of chlorinated silicon dioxide, add 100 parts of water, add 0.8 parts of allyl hydroxyethyl ether, 1.5 parts of hydroxyethyl acrylate, stir uniformly, stir at 25℃ for 12h, filter, wash and dry the solid, obtain modified silicon dioxide;

[0060] S3: Mix 13 parts of 1-hydroxybenzotriazole, 18 parts of 5-chlorobenzimidazole-2-thiol, 10 parts of sodium carbonate, 80 parts of tetrahydrofuran uniformly, stir at 60℃ for 6h, remove the solvent, obtain weather-resistant antioxidant;

[0061] S4: Take 2.5 parts of triallylphenylsilane, add 60 parts of ethanol and stir uniformly, add 3 parts of weather-resistant antioxidant, 8 parts of mercapto-polyethylene glycol-hydroxyl, 1.5 parts of 1-thioglycerol, stir uniformly, add 0.01 parts of photoinitiator, stir under ultraviolet light for 6min, remove the solvent, obtain polyhydroxy additive;

[0062] S5: Take 28 parts of polyhydroxy additive, 2 parts of ethylene glycol, 16 parts of neopentyl glycol, 25 parts of isophthalic acid, heat to 160℃ under nitrogen protection, stir uniformly, add 0.1 parts of dibutyl tin laurate, heat for 2h, heat to 220℃, heat until the acid value is 100mg / g, cool to 85℃; add 20 parts of neopentyl glycol, 20 parts of maleic anhydride, heat to 160℃ for 1h, then heat to 220℃ until the acid value is 5mg / g, obtain polyester;

[0063] S6: Take 45 parts of polyester, 12 parts of acrylic resin, 0.1 parts of defoaming agent, 0.3 parts of dispersant, 0.3 parts of leveling agent, 0.1 parts of anti-sagging aid, mix uniformly, add 12 parts of modified silicon dioxide, stir uniformly, obtain component A; take mass ratio of 1:2 of cobalt isooctoate and methyl ethyl ketone peroxide, mix, obtain component B; mix component A and component B according to mass ratio of 100:2, obtain clear paint.

[0064] Performance test: take the clear paint prepared in examples 1~3 and comparative examples 1~4, cure to obtain 50μm coating, detect; (1) detect its adhesion; (2) refer to GB / T1865, test its gloss 1, then irradiate the coating with xenon lamp for 1500h, test the gloss 2 again, calculate the gloss retention to evaluate its weather resistance; gloss retention=(gloss 2 / gloss 1)×100%; see table 1 in detail;

[0065] Table 1:

[0066] adhesion gloss retention / % example 1 5B 74.2 example 2 5B 72.9 example 3 5B 73.1 comparative example 1 5B 68.2 comparative example 2 4B 63.9 comparative example 3 4B 66.0 comparative example 4 4B 66.7

[0067] Conclusion: The performance of Comparative Example 1 and Comparative Example 2 is not as good as that of the embodiment, which indicates that the branching degree needs to be strictly controlled; the performance of Comparative Example 3 is reduced due to the compatibility and other factors, because the preparation method of the modified silica is changed, and the nano-silica, allyl hydroxyethyl ether and hydroxyethyl acrylate are directly stirred uniformly to obtain the modified silica; the performance is reduced due to the compatibility problem and the poor leveling property caused by the increase of the acrylic resin in Comparative Example 4, which indicates that it is important to control the addition amount of the raw materials; in conclusion, the varnish coating prepared by the application has good adhesion, good leveling property, no sagging and good weather resistance.

[0068] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A method for preparing a high-adhesion, high-weather-resistant varnish coating, characterized in that: Includes the following steps: S1: Take triallylphenylsilane, add it to ethanol and stir evenly, add weather-resistant antioxidant, mercapto-polyethylene glycol-hydroxyl, 1-thioglycerol, stir evenly, add photoinitiator, stir under ultraviolet light for 5~10 minutes, remove solvent, and obtain polyhydroxyl additive. S2: Take polyhydroxy additives, ethylene glycol, neopentyl glycol, and isophthalic acid, heat to 160~170℃ under nitrogen protection, stir evenly, add dibutyltin laurylate, keep warm for 1~2 hours, heat to 200~220℃ and keep warm until the acid value is ≤100mg / g, then cool to 80~85℃; add neopentyl glycol and maleic anhydride, heat to 160~170℃ and keep warm for 1~2 hours, then heat to 200~220℃ and keep warm until the acid value is ≤5mg / g to obtain polyester; S3: Take polyester, acrylic resin, defoamer, dispersant, leveling agent, and anti-sagging agent, mix them evenly, add modified silica, and stir evenly to obtain component A; take cobalt isooctanoate and methyl ethyl ketone peroxide and mix them to obtain component B; mix component A and component B, adjust the viscosity, and obtain clear varnish coating; The polyhydroxy additive comprises the following raw materials, in parts by weight: 2-2.5 parts triallylphenylsilane, 50-150 parts ethanol, 3-3.5 parts weather-resistant antioxidant, 8-10 parts mercapto-polyethylene glycol-hydroxy, 1-1.5 parts 1-thioglycerol, and 0.01-0.015 parts photoinitiator; The preparation of the weather-resistant antioxidant includes the following steps: 1-hydroxybenzotriazole, 5-chlorobenzimidazole-2-thiol, sodium carbonate, and tetrahydrofuran are mixed evenly and stirred at 50~60℃ for 4~6h. The solvent is removed to obtain the weather-resistant antioxidant. The weather-resistant and antioxidant agent comprises the following raw materials, in parts by weight: 10-15 parts 1-hydroxybenzotriazole, 16-20 parts 5-chlorobenzimidazole-2-thiol, 8-12 parts sodium carbonate, and 60-80 parts tetrahydrofuran.

2. The method for preparing a high-adhesion, high-weather-resistant varnish coating according to claim 1, characterized in that: The polyester comprises the following raw materials, by mass parts: 20-30 parts polyhydroxy additives, 2-3 parts ethylene glycol, 30-50 parts neopentyl glycol, 20-25 parts isophthalic acid, 0.1-0.2 parts dibutyltin laurate, and 15-25 parts maleic anhydride.

3. The method for preparing a high-adhesion, high-weather-resistant varnish coating according to claim 1, characterized in that: Component A comprises the following raw materials, by mass parts: 40-50 parts polyester, 6-10 parts acrylic resin, 0.1-0.2 parts defoamer, 0.3-0.5 parts dispersant, 0.3-0.5 parts leveling agent, 0.1-0.2 parts anti-sagging agent, and 10-15 parts modified silica; Component B comprises cobalt isooctanoate and methyl ethyl ketone peroxide in a mass ratio of 1:(2-3); the mass ratio of component A to component B is 100:(1-2).

4. The method for preparing a high-adhesion, high-weather-resistant varnish coating according to claim 1, characterized in that: The preparation of the modified silica includes the following steps: Nano-silica and chloromethyltrimethoxysilane were added to an ethanol aqueous solution, the pH was adjusted to 5-6, and the mixture was stirred at 50-60℃ for 6-8 hours. After filtration, the solid was washed and dried to obtain chlorinated silica. The chlorinated silica was then added to water, along with allyl hydroxyethyl ether and hydroxyethyl acrylate. The mixture was stirred evenly at 25-30℃ for 8-12 hours, and after filtration, the solid was washed and dried to obtain modified silica.

5. The method for preparing a high-adhesion, high-weather-resistant varnish coating according to claim 4, characterized in that: The chlorinated silica comprises the following raw materials, by mass: 10-15 parts nano silica, 1-2 parts chloromethyltrimethoxysilane; the modified silica comprises the following raw materials, by mass: 10-15 parts chlorinated silica, 0.5-1 parts allyl hydroxyethyl ether, 1-2 parts hydroxyethyl acrylate.

6. The varnish coating prepared by the method for preparing a high-adhesion, high-weather-resistant varnish coating according to any one of claims 1 to 5.