Highlight varnish with ultraviolet aging resistance and wear resistance as well as preparation method and application of highlight varnish

Abstract

The invention relates to the field of functional coatings, in particular to highlight varnish with ultraviolet aging resistance and wear resistance as well as a preparation method and application of the highlight varnish. Organic silicon modified polyurethane resin is developed firstly, the self-made organic silicon modified polyurethane resin and hydroxy acrylic resin are matched to serve as a resin component in a varnish formula, and auxiliary components in the varnish formula are further adjusted; therefore, the wear-resistant highlight varnish with ultraviolet aging resistance, wear resistance and impact toughness is obtained. The wear-resistant highlight varnish provided by the invention is applied to the surface of colored paint, has excellent binding force with the colored paint, can effectively improve the anti-aging performance and scratch resistance of a coating, has good impact toughness and high and low temperature alternation performance, and can ensure that the gloss of the coating is 90 degrees or above.

Description

Technical Field

[0001] The invention relates to the field of functional coatings, and more particularly to a high-gloss varnish with UV aging resistance and wear resistance, and a preparation method and application thereof. Background Art

[0002] Protective coatings are sprayed on the surfaces of transportation vehicles such as airplanes, high-speed trains, and automobiles. The purpose is to protect the surface from chemical or electrochemical reactions with the surrounding medium, prevent or delay the surface from being damaged, and provide decorative effects for the surface of transportation vehicles. With the development of the industry, the demand for protective coatings continues to increase, and the performance requirements for coatings have also evolved from simple anti-corrosion and aesthetics to good aging resistance, excellent wear resistance, and resistance to environmental variability.

[0003] The most common problems encountered during the use of protective coatings on aircraft, high-speed trains, and automobiles are UV aging and surface scratches. Protective coatings will age under long-term exposure to ultraviolet rays. The most direct impact is that the paint film loses its gloss and changes color. Severe aging can cause the paint film to powder, and even reduce strength, crack, blister, crack, and fall off, which will render the protective effect of the protective coating ineffective. During high-speed operation, the protective coating is easily scratched by rain, dust, gravel, and debris mixed in the airflow. In severe cases, the coating may penetrate and expose the substrate, accelerating corrosion of the substrate surface, causing the protective performance of the coating to fail and shortening its service life. These two problems, UV aging and surface scratches, significantly affect the performance of the protective coating and may even threaten driving safety.

[0004] As the outermost layer of the protective coating, the varnish is applied on the primer and topcoat as a whole. The protective coating formed by the existing varnish is difficult to achieve: high resistance to UV aging and wear resistance while having good mechanical properties. Summary of the invention

[0005] Technical problem to be solved: The protective coating formed by the existing varnish is difficult to have high resistance to UV aging, wear resistance and impact toughness.

[0006] The present invention first develops a silicone modified polyurethane resin, and uses the homemade silicone modified polyurethane resin and hydroxy acrylic resin as the resin component in the varnish formula, and further adjusts the auxiliary agent component in the varnish formula, thereby obtaining a wear-resistant high-gloss varnish that takes into account UV aging resistance, wear resistance and impact toughness. The wear-resistant high-gloss varnish provided by the present invention is applied on the surface of the color paint, has excellent bonding strength with the color paint, can effectively improve the anti-aging and scratch resistance of the coating, and has good impact toughness and high and low temperature alternating performance, and can ensure that the gloss of the coating is above 90°.

[0007] One of the objects of the present invention is to provide a high gloss varnish (hereinafter referred to as high gloss varnish) with high resistance to ultraviolet aging and wear.

[0008] The high-gloss varnish with high resistance to ultraviolet aging and wear resistance comprises a base material, a curing material and a diluent; the weight ratio of the base material, the curing material and the diluent is 2: (1.0-1.3): (1.2-2.4), preferably 2: (1.1-1.2): (1.8-2.4);

[0009] Based on 100 parts by weight of the total weight of the base material, the base material comprises the following components:

[0010] 20-40 parts by weight, preferably 25-35 parts by weight, of organosilicon-modified polyurethane resin;

[0011] 30-60 parts by weight, preferably 35-55 parts by weight, of hydroxy acrylic resin;

[0012] 1.0-3.5 parts by weight of anti-sagging agent, preferably 2.0-3.0 parts by weight;

[0013] Defoaming agent 0.1-0.5 weight part, preferably 0.1-0.3 weight part;

[0014] 0.5-2.0 parts by weight of leveling agent, preferably 0.5-1.5 parts by weight;

[0015] 1-10 parts by weight, preferably 2-5 parts by weight, of a light stabilizer;

[0016] 1-10 parts by weight of ultraviolet absorber, preferably 2-5 parts by weight;

[0017] 5-25 parts by weight of base solvent, preferably 10-20 parts by weight;

[0018] Based on 100 parts by weight of the total weight of the curing material, the curing material includes the following components:

[0019] 70-100 parts by weight of curing agent, preferably 75-100 parts by weight;

[0020] The curing agent solvent is 0-30 parts by weight, preferably 0-25 parts by weight.

[0021] The hydroxy acrylic resin can be any existing hydroxy acrylic resin that can be used for varnish. As a preferred embodiment, the hydroxy value of the hydroxy acrylic resin is greater than 150; the hydroxy value is defined as the number of milligrams of potassium hydroxide equivalent to the hydroxyl group in 1g of the sample. Specifically, at least one of Allnex 2155 acrylic resin, Allnex 4266 acrylic resin, Allnex 2810 acrylic resin, and Mitsubishi Chemical 7908 acrylic resin can be used.

[0022] The anti-sagging agent can be any existing anti-sagging agent that can be used for varnish. As a preferred embodiment, the anti-sagging agent is at least one of a modified polyamide solution anti-sagging agent (such as anti-sagging agent BYK 430) and a modified urea anti-sagging agent (such as anti-sagging agent BYK410, VOK-7410ET, etc.).

[0023] The defoamer can be any existing defoamer that can be used for varnish. As a preferred embodiment, the defoamer is at least one of a foam-breaking polymer solution (such as defoamer BYK054, BYK057, etc.) or a polysiloxane solution (such as defoamer BYK024).

[0024] The leveling agent can be any existing leveling agent that can be used for varnish. As a preferred embodiment, the leveling agent is at least one of a polyether-modified silicone leveling agent (such as leveling agent BYK333), an acrylate leveling agent such as leveling agent BYK354, or a fluorocarbon-modified polyacrylate polymer (such as leveling agent AFCONA-3700).

[0025] The light stabilizer can be any existing light stabilizer that can be used for varnish. As a preferred embodiment, the light stabilizer is at least one of a hindered amine light stabilizer (such as light stabilizer UV-292, UV-123, etc.) or a composite light stabilizer (such as light stabilizer UV-791).

[0026] The ultraviolet absorber can be any existing ultraviolet absorber that can be used for varnish. As a preferred embodiment, the ultraviolet absorber is at least one of a triazine ultraviolet absorber (such as ultraviolet absorber UV-1164) and a benzotriazole ultraviolet absorber (such as ultraviolet absorber UV-326, UV-328, etc.); the ultraviolet aging resistance can be significantly improved by compounding ultraviolet absorbers with different action mechanisms and anti-ultraviolet additives.

[0027] The base solvent can be any existing base solvent that can be used for varnish. As a preferred embodiment, the base solvent is one or more of butyl acetate, methyl isobutyl ketone, and propylene glycol methyl ether acetate.

[0028] The curing agent can be any existing curing agent that can be used for varnish. As a preferred embodiment, the curing agent is an aliphatic isocyanate compound with good weather resistance, more preferably a hexamethylene diisocyanate biuret curing agent or an HDI trimer curing agent; for example, Desmodur N75, Desmodur N100, Desmodur N3375, Desmodur N3390, etc.

[0029] The curing agent solvent can be any existing curing agent solvent that can be used for varnish. As a preferred embodiment, the curing agent solvent is at least one of ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, and methyl isobutyl ketone.

[0030] The diluent can be any existing diluent that can be used for varnish. As a preferred embodiment, the diluent contains butyl acetate, and more preferably, is composed of ethyl acetate, butyl acetate, methyl isobutyl ketone, and propylene glycol methyl ether acetate in a mass ratio of (0.1-2): (4-6): (0.1-3): (0.1-3).

[0031] The organosilicon-modified polyurethane resin is self-made by the present invention. The organosilicon-modified polyurethane resin is obtained by adding a solvent after a stepwise polymerization reaction of raw materials including terminal hydroxyl polydimethylsiloxane, polycaprolactone polyol, diisocyanate, chain extender and catalyst.

[0032] The preparation method of the organosilicon-modified polyurethane resin comprises the following steps:

[0033] (1) fully mixing polycaprolactone polyol, diisocyanate and hydroxy-terminated polydimethylsiloxane, and reacting them at 75-85° C. for 1.5-2 h under nitrogen protection;

[0034] (2) Cool down to 40-50°C, add chain extender and catalyst, and mix thoroughly;

[0035] (3) Raise the temperature to 70-80°C and react for 2-3 hours;

[0036] (4) Cooling to 50-60° C., adding a solvent, and stirring evenly to obtain the organosilicon-modified polyurethane resin.

[0037] In the raw materials for preparing the organosilicon-modified polyurethane resin, the terminal hydroxyl polydimethylsiloxane can be selected in a wide range. The molecular weight change of the terminal hydroxyl polydimethylsiloxane will affect the performance of the prepared organosilicon-modified polyurethane resin in high gloss varnish. As a preferred embodiment, the number average molecular weight of the terminal hydroxyl polydimethylsiloxane is 500-3500, more preferably 1000-3000.

[0038] In the raw materials for preparing the organosilicon-modified polyurethane resin, the polycaprolactone polyol can be selected in a wide range. The molecular weight change of the polycaprolactone polyol will affect the performance of the prepared organosilicon-modified polyurethane resin in high gloss varnish. As a preferred embodiment, the number average molecular weight of the polycaprolactone polyol is 300-2500, more preferably 1000-2000.

[0039] In the raw materials for preparing the organosilicon-modified polyurethane resin, the diisocyanate is one or more of dicyclohexylmethane diisocyanate or isophorone diisocyanate. Both dicyclohexylmethane diisocyanate and isophorone diisocyanate are aliphatic isocyanates, and do not contain a benzene ring in the structure, which can increase the anti-yellowing performance of the organosilicon-modified polyurethane resin in high-gloss varnish; the selected HMDI and IPDI both contain a cyclohexane structure similar to a benzene ring and have good reactivity, so that the prepared organosilicon-modified polyurethane resin exhibits excellent impact resistance and tear resistance in high-gloss varnish.

[0040] In the raw materials for preparing the organosilicon-modified polyurethane resin, the chain extender can be any chain extender that can be used for synthesizing organosilicon-modified resin. As a preferred embodiment, the chain extender is one of 1,4-butanediol and ethylene glycol.

[0041] In the raw materials for preparing the organosilicon-modified polyurethane resin, the catalyst can be any catalyst that can be used for the synthesis of organosilicon-modified resin. As a preferred embodiment, the catalyst is dibutyltin dilaurate (DBTDL).

[0042] In the raw materials for preparing the organosilicon-modified polyurethane resin, the solvent can be any solvent that can be used for the synthesis of organosilicon-modified resin. As a preferred embodiment, the solvent is composed of ethyl acetate, butyl acetate, and methyl isobutyl ketone in a mass ratio of (1-3): (4-6): (1-3).

[0043] The amount of raw materials used to prepare the organosilicon-modified polyurethane resin can be selected in a wide range. The change in the amount ratio of the raw materials used to prepare the organosilicon-modified polyurethane resin will affect the performance of the prepared organosilicon-modified polyurethane resin in high-gloss varnish. As a preferred embodiment, based on the total weight of the raw materials and the solvent as 100%, the following components are present: 30%-55% polycaprolactone polyol, 5%-25% terminal hydroxyl polydimethylsiloxane, 20%-40% diisocyanate, 5%-15% chain extender, and 0.5%-1% catalyst. More preferably, based on the total weight of the raw materials as 100%, the following components are present: 35%-55% polycaprolactone polyol, 10%-20% terminal hydroxyl polydimethylsiloxane, 20%-35% diisocyanate, 5%-12% chain extender, and 0.1%-0.5% catalyst.

[0044] Compared with existing organosilicon-modified resins, the organosilicon-modified polyurethane resin prepared by the present invention has an increased crosslinking density, and its hardness is significantly improved after film formation with high-hydroxy acrylate and curing agent. Generally, increasing the crosslinking density of organosilicon-modified resins can increase the hardness of the paint film, but at the same time it will reduce the elasticity and toughness of the paint film and make the paint film very brittle. The present invention selects polycaprolactone polyol as the soft segment of the organosilicon-modified polyurethane resin, which improves the toughness and impact resistance of the organosilicon-modified polyurethane resin while increasing the crosslinking density of the organosilicon-modified polyurethane resin; when the prepared organosilicon-modified polyurethane resin is used in high-gloss varnish, it can significantly improve the hardness, wear resistance, scratch resistance, elasticity, toughness, impact resistance and tear resistance of the paint film.

[0045] The organosilicon-modified polyurethane resin prepared by the present invention does not contain a benzene ring in its structure, which can increase the yellowing resistance of the organosilicon-modified polyurethane resin in high-gloss varnish. The present invention selects polycaprolactone polyol as a chain segment of the organosilicon-modified polyurethane resin, which can make the prepared organosilicon-modified polyurethane resin have excellent yellowing resistance in high-gloss varnish.

[0046] For the appearance decorative coating, its gloss and saturation are very important. After the general organosilicon-modified resin is used in varnish, the gloss performance of the varnish will be lost and it is difficult to achieve above 90°. After the organosilicon-modified polyurethane resin prepared by the present invention is used in high-gloss varnish, the gloss of the coating can be guaranteed to be above 90° under the premise of achieving high hardness and high durability.

[0047] The second object of the present invention is to provide a method for preparing the high-gloss varnish with high resistance to ultraviolet aging and wear resistance as described in the first object of the invention.

[0048] The preparation method comprises: stirring and mixing the components of the base material according to the weight proportions to obtain the base material; stirring and mixing the components of the curing material according to the weight proportions to obtain the curing material; and mixing the base material, the curing material and the diluent according to the amounts to obtain the high-gloss varnish.

[0049] The preparation method can specifically adopt the following scheme:

[0050] Preparation of base material:

[0051] Prepare the paint mixing tank, weigh the raw materials according to the amount specified in the formula, add them into the paint mixing tank in sequence, and use a high-speed disperser to disperse and stir after all the raw materials are added; the stirring speed is controlled at (600-900) r / min, and the stirring time is preferably sufficient to stir evenly, usually about 30 minutes; after the dispersion is completed, the paint is mixed and the non-volatile content is adjusted to be within the range of 60±2%; after the product performance inspection is qualified, filter and package;

[0052] Preparation of curing material:

[0053] Prepare the paint mixing tank, weigh the raw materials according to the amount specified in the formula, and add them to the paint mixing tank in sequence; after all the raw materials are added, use a high-speed disperser to disperse and stir; the stirring speed is controlled at (200-400) r / min, and the stirring time is preferably sufficient to stir evenly, usually about 20 minutes; filter and package the product after it passes the performance inspection;

[0054] Preparation of diluent:

[0055] Prepare the paint mixing tank, weigh the raw materials according to the amount specified in the formula, and add them into the paint mixing tank in sequence; after all the raw materials are added, use a high-speed disperser to disperse and stir; the stirring speed is controlled at (100-300) r / min, and the stirring time is preferably sufficient to stir evenly, usually about 10 minutes; filter and package the product after passing the performance inspection.

[0056] The third object of the present invention is to provide a use of the high-gloss varnish with high UV aging resistance and wear resistance as described in the first object of the invention in a protective coating.

[0057] The application includes mixing the base material, curing material and diluent according to the amount, stirring them fully, standing and aging them to reach the construction viscosity, and then coating and curing them. Preferably, the standing and aging time is 15-30 minutes, the construction viscosity is 12-28 seconds, the coating method is spraying, and the spray dry film thickness after curing is 25-40 μm.

[0058] The application may specifically adopt the following solutions:

[0059] The high-gloss varnish with high UV aging resistance and wear resistance described in one of the objectives of the invention is used in combination with a color paint. The initial substrate treatment is mainly to polish the color paint to activate the surface, and finely polish with sandpaper of 800 mesh or above to improve the wetting ability of the high-gloss varnish to the color paint; after the polishing is completed, the surface is cleaned with ethyl acetate or butyl acetate to ensure that there is no oil stain and powder residue on the surface;

[0060] The high-gloss varnish of the invention comprises three components: a base material, a curing material and a diluent; before construction, the base material, the curing agent and the diluent are mixed and stirred in proportion, and then left to stand and mature for 15-30 minutes; the general construction viscosity is between 12-28 seconds; it is recommended to filter with a filter cloth with a mesh size of 100 or more before spraying; the spray dry film thickness is controlled to be 25-40 μm; air dynamic spraying is preferably used for spraying, and the atomization pressure of the nozzle with a diameter of 1.0-1.5 mm is controlled to be 0.3-0.5 MPa; when spraying, the spray gun should be moved at a uniform speed perpendicular to the spraying surface; after the paint film is sprayed, it can be surface dried for 2 hours at room temperature, and can be completely dried for 24 hours, and it takes 7 days to be completely cured; the coating film can also be cured by heating, but it needs to be placed at room temperature for at least 2 hours and then placed in a 60°C oven for at least 4 hours.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The silicone modified polyurethane resin prepared by the present invention is matched with a high hydroxyl acrylic resin and cross-linked with a curing agent to form a film. This has several advantages: first, the silicone chain segments migrate to the surface to play a shielding role, which can increase weather resistance and medium resistance; second, the high hydroxyl group forms a film with the trimer, improves the cross-linking density, and together with the silicone chain segments, greatly increases the hardness of the paint film and improves the wear resistance; third, by adjusting the content of the silicone group, more polar groups are still present on the coating surface, which will not affect the recoating performance of the paint film, and the glossiness will not be reduced.

[0063] The high-gloss varnish with high UV aging resistance and wear resistance provided by the present invention is applied on the surface of the color paint, can effectively improve the anti-aging performance and scratch resistance of the coating, and at the same time has good impact toughness and high and low temperature alternating performance, and excellent bonding with the color paint. It has the advantages of high gloss, strong UV resistance, good wear resistance and good recoatability. It can be widely used in equipment and transportation vehicles serving in outdoor environments with strong light and wind and sand, and has considerable application value and economic value. DETAILED DESCRIPTION

[0064] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0065] The raw materials used in the following examples and comparative examples are all commercially available products.

[0066] Polycaprolactone polyols are derived from Aladdin reagent, Mn1000-2000;

[0067] Hydroxyl-terminated polydimethylsiloxane is derived from Aladdin reagent, Mn1000-2000.

[0068] Example 1

[0069] (1) Preparation of silicone-modified polyurethane resin:

[0070] 15 g of terminal hydroxyl polydimethylsiloxane was ultrasonically dispersed in 20 g of solvent methyl isobutyl ketone to obtain a terminal hydroxyl polydimethylsiloxane solution; 35 g of polycaprolactone polyol and 30 g of dicyclohexylmethane diisocyanate (Aladdin reagent, isomer mixture) were added to a flask equipped with a stirring paddle, a thermometer, a condenser and a nitrogen protection device and mixed thoroughly, the terminal hydroxyl polydimethylsiloxane solution was added to the flask, stirred thoroughly for 30 min, heated to 80° C. under nitrogen protection for reaction for 2 h, cooled to 50° C., 5 g of chain extender 1-4 butanediol and 0.2 g of catalyst dibutyltin dilaurate were added, the temperature was raised to 70° C. after thorough mixing, reacted for 3 h, cooled to 60° C., a solvent was added (the solvent was composed of ethyl acetate, butyl acetate and methyl isobutyl ketone in a mass ratio of 2:2:1), and the material was discharged after cooling to obtain a silicone modified polyurethane resin.

[0071] (2) Preparation of base material:

[0072] The raw material formula of the base material: 25 g of the silicone modified polyurethane resin prepared in step (1), 46 g of hydroxyl acrylic resin (Zhanxin 2810), 2 g of anti-sagging agent (BYK410), 0.3 g of defoaming agent (BYK054), 0.7 g of leveling agent (AFCONA3700), 3 g of light stabilizer (UV-791), 3 g of ultraviolet absorber (UV-1164), 10 g of butyl acetate, and 10 g of propylene glycol methyl ether acetate.

[0073] The base material preparation process is as follows: prepare a paint mixing tank, add each base material raw material into the paint mixing tank according to the formula. After all the raw materials are added, use a high-speed disperser to disperse and stir, filter and package. The stirring speed is controlled at 600r / min and the stirring time is 30min.

[0074] (3) Preparation of curing material:

[0075] The raw material formula of the curing material: Desmodur N3390 78g, butyl acetate 22g.

[0076] The preparation process of the curing material is as follows: prepare a paint mixing tank, add the raw materials of the curing material into the paint mixing tank according to the formula. After all the raw materials are added, use a high-speed disperser to disperse and stir, filter and package. The stirring speed is controlled at 200r / min and the stirring time is 20min.

[0077] (4) Preparation of diluent:

[0078] The raw material formula of the diluent: 50g butyl acetate, 30g ethyl acetate, and 20g propylene glycol methyl ether acetate.

[0079] The preparation process of the diluent is as follows: prepare a paint mixing tank, add the raw materials into the paint mixing tank according to the formula. After all the raw materials are added, use a high-speed disperser to disperse and stir, filter and package. The stirring speed is controlled at 100r / min and the stirring time is 10min.

[0080] (5) Preparation of high gloss varnish:

[0081] The weight ratio of base material, curing material and diluent is 2:1.2:2.

[0082] The construction process is as follows: first mix the base material, curing material and diluent in proportion and stir, then let it stand for 15 minutes, and the construction viscosity is 15 seconds. Filter with a filter cloth of 100 mesh or more before spraying. Spraying adopts air power spraying, and the nozzle diameter is 1.2mm and the atomization pressure is controlled at 0.4MPa. When spraying, the spray gun should move at a constant speed perpendicular to the spraying surface. After the paint film is sprayed, it will be dry for 2 hours at room temperature, and it will be dry for 24 hours. It will take 7 days to fully cure. The dry film thickness of the paint film is 25-40μm.

[0083] Example 2

[0084] (1) Preparation of silicone-modified polyurethane resin:

[0085] 10g of terminal hydroxyl polydimethylsiloxane is ultrasonically dispersed in 20g of solvent methyl isobutyl ketone to obtain a terminal hydroxyl polydimethylsiloxane solution; 50g of polycaprolactone polyol and 35g of dicyclohexylmethane diisocyanate (Aladdin reagent) are added to a flask equipped with a stirring paddle, a thermometer, a condenser and a nitrogen protection device and mixed thoroughly, the terminal hydroxyl polydimethylsiloxane solution is added to the flask, stirred thoroughly for 30min, heated to 75°C under nitrogen protection for reaction for 2h, cooled to 50°C, 10g of chain extender ethylene glycol and 0.5g of catalyst dibutyltin dilaurate are added, the temperature is raised to 70°C after thorough mixing, reacted for 3h, cooled to 60°C, a solvent is added (the solvent is composed of ethyl acetate, butyl acetate and methyl isobutyl ketone in a mass ratio of 2:2:1), and the material is discharged after cooling to obtain a silicone modified polyurethane resin.

[0086] (2) Preparation of base material:

[0087] The raw material formula of the base material is as follows: 35 g of the organosilicon-modified polyurethane resin prepared in step (1), 40 g of acrylic resin (Mitsubishi 7908), 2.5 g of anti-sagging agent (BYK430), 0.2 g of defoaming agent (BYK054), 1.3 g of leveling agent (BYK354), 5 g of light stabilizer (UV-292), 5 g of ultraviolet absorber (UV-328), 6 g of butyl acetate, and 5 g of methyl isobutyl ketone.

[0088] The base material preparation process is the same as that in Example 1.

[0089] (3) Preparation of curing material:

[0090] The raw material formula of the curing material: Desmodur N100 70g, butyl acetate 30g.

[0091] The preparation process of the solidifying material is the same as that in Example 1.

[0092] (4) Preparation of diluent:

[0093] The raw material formula of the diluent: 50g butyl acetate, 30g propylene glycol methyl ether acetate, and 20g methyl isobutyl ketone.

[0094] The preparation process of the diluent is the same as that in Example 1.

[0095] (5) Preparation of high gloss varnish:

[0096] The weight ratio of base material, curing material and diluent is 2:1:2.

[0097] The construction process is the same as that of Example 1.

[0098] Example 3

[0099] (1) Preparation of silicone-modified polyurethane resin:

[0100] 15 g of terminal hydroxyl polydimethylsiloxane was ultrasonically dispersed in 20 g of methyl isobutyl ketone solvent to obtain a terminal hydroxyl polydimethylsiloxane solution; 50 g of polycaprolactone polyol and 20 g of isophorone diisocyanate (Aladdin reagent) were added to a flask equipped with a stirring paddle, a thermometer, a condenser and a nitrogen protection device, and the mixture was fully mixed; the terminal hydroxyl polydimethylsiloxane solution was added to the flask, and the mixture was fully stirred for 30 min. The mixture was heated to 85° C. under nitrogen protection and reacted for 2 h. After cooling to 50° C., 10 g of 1-4 butanediol chain extender and 0.5 g of dibutyltin dilaurate catalyst were added. The mixture was fully mixed and heated to 80° C. After reacting for 3 h, the mixture was cooled to 60° C., a solvent was added (the solvent was composed of ethyl acetate, butyl acetate and methyl isobutyl ketone in a mass ratio of 2:2:1), and the mixture was discharged after cooling to obtain a silicone modified polyurethane resin.

[0101] (2) Preparation of base material:

[0102] The raw material formula of the base material: 40 g of the silicone modified polyurethane resin prepared in step (1), 35 g of acrylic resin (Zhanxin 2155), 3 g of anti-sagging agent (BYK430), 0.3 g of defoaming agent (BYK024), 1.5 g of leveling agent (BYK333), 2 g of light stabilizer (UV-124), 3.2 g of ultraviolet absorber (UV-326), and 15 g of methyl isobutyl ketone.

[0103] The base material preparation process is the same as that in Example 1.

[0104] (3) Preparation of curing material:

[0105] The raw material formula of the curing material: Desmodur N3390 78g, butyl acetate 23g.

[0106] The preparation process of the solidifying material is the same as that in Example 1.

[0107] (4) Preparation of diluent:

[0108] The raw material formula of the diluent: 60g butyl acetate, 20g ethyl acetate, and 20g methyl isobutyl ketone.

[0109] The preparation process of the diluent is the same as that in Example 1.

[0110] (5) Preparation of high gloss varnish:

[0111] The weight ratio of base material, curing material and diluent is 2:1.2:2.

[0112] The construction process is the same as that of Example 1.

[0113] Comparative Example 1

[0114] Raw material formula of base material: 75g of Allnex 2810 resin, 2.5g of anti-sagging agent (BYK430), 0.2g of defoaming agent (BYK054), 1.3g of leveling agent (BYK354), 5g of light stabilizer (UV-292), 5g of ultraviolet absorber (UV-328), 6g of butyl acetate, and 5g of methyl isobutyl ketone.

[0115] The base material preparation process is the same as that in Example 1.

[0116] Raw material formula of curing material:

[0117] Desmodur N100 70g, butyl acetate 30g.

[0118] The preparation process of the solidifying material is the same as that in Example 1.

[0119] Raw material formula of diluent:

[0120] Butyl acetate 50g, propylene glycol methyl ether acetate 30g, methyl isobutyl ketone 20g.

[0121] The preparation process of the diluent is the same as that in Example 1.

[0122] The weight ratio of base material, curing material and diluent is 2:0.6:2.

[0123] The construction process is the same as that of Example 1.

[0124] Comparative Example 2

[0125] The raw material formula of the base material: 75g of Xinsihai Chemical SH-024 silicone resin, 2g of anti-sagging agent (BYK410), 0.3g of defoaming agent (BYK057), 1.3g of leveling agent (BYK354), 5g of light stabilizer (UV-292), 5g of ultraviolet absorber (UV-328), 6g of butyl acetate, and 5g of methyl isobutyl ketone.

[0126] The base material preparation process is the same as that in Example 1.

[0127] Raw material formula of curing material:

[0128] Desmodur N100 70g, butyl acetate 30g.

[0129] The preparation process of the solidifying material is the same as that in Example 1.

[0130] Raw material formula of diluent:

[0131] Butyl acetate 50g, propylene glycol methyl ether acetate 30g, methyl isobutyl ketone 20g.

[0132] The preparation process of the diluent is the same as that in Example 1.

[0133] The weight ratio of base material, curing material and diluent is 3:1:3.

[0134] The construction process is the same as that of Example 1.

[0135] Performance Testing

[0136] The properties of the paint films formed in Examples 1-3 and Comparative Examples 1-2 were tested, requiring the varnish to be coated on the surface of the color paint; the test standards, test methods and technical index requirements to be achieved by the varnish are shown in Table 1; the test results are shown in Table 2.

[0137] Table 1

[0138]

[0139] In Table 1, A, B, and C represent base material, curing material, and diluent, respectively.

[0140] Specific paint film properties:

[0141] Table 2

[0142]

[0143] From the test results shown in Table 2, it can be seen that the paint films prepared in Examples 1-3 have good mechanical properties, and their flexibility, impact adhesion, etc. all meet the index requirements. They not only have good resistance to UV aging and wear resistance, but also have excellent mechanical properties, excellent recoatability, high gloss characteristics and excellent high and low temperature alternating performance.

[0144] Compared with Comparative Example 1 and Comparative Example 2, Examples 1-3 use different resin components; Examples 1-3 use a homemade silicone-modified polyurethane resin and an acrylic resin as the resin component of the high-gloss varnish, Comparative Example 1 uses a non-silicone-modified resin as the resin component of the varnish, and Comparative Example 2 uses an existing silicone-modified resin as the resin component of the varnish.

[0145] Table 2 shows that compared with Comparative Example 1, the hardness of Examples 1-3 is improved by two levels, the adhesion is improved by one level, the corrosion resistance is improved, the UV aging resistance (the light retention rate is improved by 11-13%, the color retention rate is improved by 58-65%), and the wear resistance is improved by 77-86%. It is shown that compared with the existing resin (non-organosilicon modified), the present invention uses a homemade organosilicon modified polyurethane resin and an acrylic resin compound as the resin component of the varnish, which can improve the hardness, adhesion, corrosion resistance, UV aging resistance (light retention rate, color retention rate) and wear resistance of the varnish. The possible reason is that the organosilicon modified polyurethane resin synthesized by the present invention moves to the surface during film formation, which can play an effective shielding role, not only increasing the anti-corrosion performance, but also improving the UV aging resistance of the coating. In addition, there are a large number of hydroxyl groups in the acrylic resin, which form a network cross-linked structure with the curing material during the film formation process, which not only increases the corrosion resistance of the coating, but also improves the hardness of the coating. In combination with the action of the organosilicon segments, the hardness of the paint film is significantly increased and the wear resistance is enhanced.

[0146] Table 2 shows that compared with Comparative Example 2, the recoatability of Examples 1-3 is improved by one level, the glossiness is improved by 11-13%, the hardness is improved by one level, the flexibility is improved by one level, the adhesion is improved by one level, the impact adhesion is improved, the high and low temperature alternating performance (low temperature impact) is improved by two levels, and the wear resistance is improved by 47-67%. It shows that compared with the existing organosilicon modified resin, the present invention uses a self-made organosilicon modified polyurethane resin and an acrylic resin as the resin component of the varnish, which can improve the recoatability, glossiness, hardness, flexibility, adhesion, impact adhesion, high and low temperature alternating performance, UV aging resistance and wear resistance of the varnish. The possible reason is that the hydroxy acrylic resin in Examples 1-3 increases the polarity of the coating surface, the toughness of the coating is also increased accordingly, the mechanical properties are improved, and the problem of poor recoatability of the coating surface caused by the organosilicon resin is avoided, and the gloss of the paint film is also guaranteed.

[0147] Table 2 shows that compared with Comparative Example 1, the hardness of Comparative Example 2 is significantly improved and the flexibility is reduced; compared with Comparative Example 1, the hardness of Examples 1-3 is significantly improved and the flexibility is equivalent; compared with Comparative Example 2, the hardness and flexibility of Examples 1-3 are significantly improved. It shows that although the use of existing organosilicon-modified resin as the resin component of the varnish can improve the hardness of the varnish, it will make the paint film brittle and reduce the flexibility of the varnish. However, the use of the self-made organosilicon-modified polyurethane resin of the present invention and the acrylic resin as the resin component of the high-gloss varnish can not only significantly improve the hardness of the varnish, but also will not make the paint film brittle due to the increase in the hardness of the varnish; that is, the hardness of the varnish can be significantly improved while maintaining the good flexibility of the varnish.

Claims

1. A high gloss varnish with high UV aging resistance and wear resistance, characterized in that: The high gloss varnish comprises a base material, a curing material and a diluent; the weight ratio of the base material, the curing material and the diluent is 2: (1.0-1.3): (1.2-2.4), preferably 2: (1.1-1.2): (1.8-2.4); Based on 100 parts by weight of the total weight of the base material, the base material comprises the following components: 20-40 parts by weight, preferably 25-35 parts by weight, of organosilicon-modified polyurethane resin; 30-60 parts by weight, preferably 35-55 parts by weight, of hydroxy acrylic resin; 1.0-3.5 parts by weight of anti-sagging agent, preferably 2.0-3.0 parts by weight; 0.1-0.5 parts by weight of defoamer, preferably 0.1-0.3 parts by weight; 0.5-2.0 parts by weight of leveling agent, preferably 0.5-1.5 parts by weight; 1-10 parts by weight, preferably 2-5 parts by weight, of a light stabilizer; 1-10 parts by weight of ultraviolet absorber, preferably 2-5 parts by weight; 5-25 parts by weight of base solvent, preferably 10-20 parts by weight; Based on 100 parts by weight of the total weight of the curing material, the curing material includes the following components: 70-100 parts by weight of curing agent, preferably 75-100 parts by weight; The curing agent solvent is 0-30 parts by weight, preferably 0-25 parts by weight.

2. The high gloss varnish according to claim 1, characterized in that: The hydroxyl value of the hydroxy acrylic resin is greater than 150; or / and, The anti-sagging agent is at least one of a modified polyamide solution anti-sagging agent and a modified urea anti-sagging agent; or / and, The defoaming agent is at least one of a foam-breaking polymer solution or a polysiloxane solution; or / and, The leveling agent is at least one of a polyether-modified silicone leveling agent, an acrylate leveling agent or a fluorocarbon-modified polyacrylate polymer; or / and, The light stabilizer is at least one of a hindered amine light stabilizer or a composite light stabilizer; or / and, The ultraviolet absorber is at least one of a triazine ultraviolet absorber and a benzotriazole ultraviolet absorber; or / and, The base material solvent is one or more of butyl acetate, methyl isobutyl ketone and propylene glycol methyl ether acetate.

3. The high gloss varnish according to claim 1, characterized in that The curing agent is selected from aliphatic isocyanate compounds, preferably selected from hexamethylene diisocyanate biuret curing agent and HDI trimer curing agent; or / and, The curing agent solvent is at least one of ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, and methyl isobutyl ketone.

4. The high gloss varnish according to claim 1, characterized in that: The diluent contains butyl acetate, and is preferably composed of ethyl acetate, butyl acetate, methyl isobutyl ketone, and propylene glycol methyl ether acetate in a mass ratio of (0.1-2):(4-6):(0.1-3):(0.1-3).

5. The high gloss varnish according to claim 1, characterized in that: The organosilicon-modified polyurethane resin is obtained by adding a solvent after a stepwise polymerization reaction of raw materials including terminal hydroxyl polydimethylsiloxane, polycaprolactone polyol, diisocyanate, a chain extender and a catalyst.

6. The high gloss varnish according to claim 5, characterized in that The preparation method of the organosilicon-modified polyurethane resin comprises the following steps: (1) fully mixing polycaprolactone polyol, diisocyanate and hydroxy-terminated polydimethylsiloxane, and reacting them at 75-85° C. for 1.5-2 h under nitrogen protection; (2) Cool down to 40-50°C, add chain extender and catalyst, and mix thoroughly; (3) Raise the temperature to 70-80°C and react for 2-3 hours; (4) Cooling to 50-60° C., adding a solvent, and stirring evenly to obtain the organosilicon-modified polyurethane resin.

7. The high gloss varnish according to claim 5, characterized in that: The number average molecular weight of the hydroxy-terminated polydimethylsiloxane is 500-3500, preferably 1000-3000; or / and The number average molecular weight of the polycaprolactone polyol is 300-2500, preferably 1000-2000; or / and, The diisocyanate is one or more of dicyclohexylmethane diisocyanate and isophorone diisocyanate; or / and, The chain extender is one of 1,4-butanediol and ethylene glycol; or / and, The catalyst is dibutyltin dilaurate; or / and, The solvent is ethyl acetate, butyl acetate, and methyl isobutyl ketone according to (1-3): (4-6): The mass ratio composition of (1-3).

8. The high gloss varnish according to claim 5, characterized in that: The organosilicon-modified polyurethane is calculated based on the total weight of the raw materials as 100%: Polycaprolactone polyol 30%-55%, terminal hydroxyl polydimethylsiloxane 5%-25%, diisocyanate 20%-40%, chain extender 5%-15%, catalyst 0.5%-1%; Preferably, Polycaprolactone polyol 35%-55%, terminal hydroxyl polydimethylsiloxane 10%-20%, diisocyanate 20%-35%, chain extender 5%-12%, catalyst 0.1%-0.5%.

9. A method for preparing a high gloss varnish according to any one of claims 1 to 8, characterized in that: The preparation method comprises: The components of the base material are stirred and mixed according to the weight proportions to obtain the base material; the components of the curing material are stirred and mixed according to the weight proportions to obtain the curing material; the base material, the curing material and the diluent are mixed according to the amounts to obtain the high gloss varnish.

10. Use of the high gloss varnish according to any one of claims 1 to 8 or the high gloss varnish prepared by the preparation method according to claim 9 in protective coatings.

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