An easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, and its preparation method and application

Abstract

The present invention provides an easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, its preparation method, and application. The varnish coating composition comprises component A and component B; component A comprises the following raw material components in parts by weight: 20-80 parts of hydroxyl acrylic resin, 3-30 parts of organosilicon-modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional auxiliary agent; component B comprises the following raw material components in parts by weight: 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent; wherein the weight ratio of component A to component B is 1:10-10:1. The varnish coating composition imparts high transparency, high gloss, good weather resistance, easy cleaning, recoatability, chemical resistance, low-temperature curing, and other characteristics to the paint film, which can meet the application requirements of carbon fiber composite automotive exterior parts.

Description

Technical Field

[0001] The present invention belongs to the field of surface coating of carbon fiber composite materials, and specifically comprises an easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, and a preparation method and application thereof. Background Art

[0002] Carbon fiber composite material (CFRP), as a new type of material with low density, high strength and high stiffness, is becoming one of the most popular lightweight materials in the fields of automobiles, rail transportation vehicles, sports equipment, etc. When it is used for the exterior surface of transportation vehicles such as rail transportation and automobiles, in order to improve the appearance and protect the substrate, the carbon fiber composite material generally needs to be painted. In order to present the special texture weaving effect of carbon fiber, most of the existing technologies use high-gloss varnish transparent coating to paint the carbon fiber composite material. However, the current high-gloss varnish is easily contaminated by dust, oil, hand sweat, etc. in the outdoor environment. After contamination, it is difficult to remove it by simple methods such as wiping. Generally, it requires the help of high-pressure steam shock to clean it. Therefore, after long-term outdoor use, it is difficult for the surface of the high-gloss varnish to maintain the high appearance requirements. In addition, the varnish with anti-graffiti properties commonly used on the market generally requires high-temperature curing, and it is difficult to balance the anti-graffiti effect and recoatability of the paint film when using graffiti additives. For carbon fiber composite materials with high recoatability requirements, their application is seriously hindered.

[0003] In view of this, how to design an easy-to-clean high-gloss varnish coating composition that can be used for surface coating of carbon fiber composite materials, so as to achieve the high-gloss varnish effect of giving carbon fiber composite materials visible fiber texture while having excellent low-temperature curing, easy cleaning, recoatability, high transparency, beautiful appearance and chemical resistance, so as to eliminate the above-mentioned defects and deficiencies in the existing technology and better serve the use needs of exterior coatings such as vehicles, is a topic that needs to be urgently solved by relevant technical personnel in the industry. Summary of the Invention

[0004] In view of the above-mentioned problems existing in the prior art, the first object of the present invention is to provide an easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials.

[0005] The second object of the present invention is to provide a method for preparing the clear coating composition as described above.

[0006] The third object of the present invention is to provide a surface treatment method.

[0007] To achieve the above first object, the technical solution adopted by the present invention includes:

[0008] The present invention discloses an easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, wherein the varnish coating composition comprises component A and component B;

[0009] The component A comprises the following raw material components in parts by weight:

[0010] 20-80 parts of hydroxy acrylic resin, 3-30 parts of organosilicon-modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional additive;

[0011] The component B comprises the following raw material components in parts by weight:

[0012] 40-90 parts of isocyanate curing agent and 10-60 parts of a second solvent;

[0013] Wherein, the weight ratio of component A to component B is 1:10-10:1;

[0014] The organosilicon-modified acrylic resin is a modified resin formed by reacting a polyacrylate resin containing a hydroxyl functional group with an organosilicon oligomer containing a hydroxyl or alkoxy functional group.

[0015] Furthermore, the component A comprises the following raw material components in parts by weight:

[0016] 30-50 parts of hydroxy acrylic resin, 5-20 parts of organosilicon modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional auxiliary agent.

[0017] Furthermore, the weight ratio of component A to component B is 1:5-5:1.

[0018] Furthermore, the organosilicon-modified acrylic resin is selected from modified acrylic resins with a water contact angle greater than 100°.

[0019] Furthermore, the organosilicon-modified acrylic resin includes but is not limited to the commercially available JZ-9522 and / or JZ-9540;

[0020] The hydroxyl value of the hydroxy acrylic resin is between 0.5-8%.

[0021] Furthermore, the hydroxylated acrylic resin includes but is not limited to one or more of Setalux 1907BA-75, TIRES 2850, SETALUX 1774SS-65, SETALUX 1215BA-68, SETALUX 1274BA-70 from Allnex, Joncryl 507, Joncryl 804, Joncryl 910 from BASF, and Hypomer MT-2550K, Hypomer MT-2550F, and Hypomer MT-2350 from Elementis.

[0022] Furthermore, the isocyanate curing agent includes, but is not limited to, one or more of aliphatic isocyanate polymers, alicyclic isocyanate polymers, aromatic isocyanate polymers, isocyanate hybrids, and isocyanate hybrid polymers.

[0023] Further, the first solvent and the second solvent are independently selected from one or more of hexane, heptane, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, butyl acetate, ethyl acetate, 3-ethoxyethyl propionate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, propylene carbonate, dimethyl carbonate, No. 100 solvent oil, No. 150 solvent oil, and No. 200 solvent oil.

[0024] Furthermore, the additional additives include one or more of a drying agent, a substrate wetting agent, a wetting and dispersing agent, a leveling agent, and a rheological additive.

[0025] Furthermore, the viscosity of the varnish coating composition at 23° C. is in the range of 100-10000 mPa·s, preferably 100-5000 mPa·s.

[0026] To achieve the above second purpose, the technical solutions adopted by the present invention include:

[0027] The present invention discloses a method for preparing the above-mentioned clear coating composition, comprising the following steps:

[0028] (1) adding a hydroxy acrylic resin, a silicone-modified acrylic resin, an additional additive, an ultraviolet light absorber, a light stabilizer, and a first solvent to a first container under stirring, and stirring until the mixture is uniformly mixed to obtain the component A;

[0029] (2) adding an isocyanate curing agent and a second solvent to a second container under stirring, and stirring until the mixture is uniform, thereby obtaining the component B;

[0030] (3) Component A and component B are mixed in proportion to obtain the varnish coating composition.

[0031] To achieve the third objective, the present invention employs the following technical solutions:

[0032] The present invention discloses a surface treatment method, which comprises coating at least one layer of the clear coating composition described above on at least one surface of a carbon fiber composite material.

[0033] Furthermore, the coating method is selected from air spraying, airless spraying, online electrostatic spraying or in-mold coating.

[0034] Beneficial effects of the present invention:

[0035] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0036] The easy-to-clean high-gloss varnish coating composition of the present invention can impart high transparency and an aesthetically pleasing high-gloss varnish effect to the carbon fiber composite material, and the carbon fiber texture of the composite material is clearly visible.

[0037] The easy-to-clean high-gloss varnish coating composition of the present invention has good weather resistance and can provide good protection for the surface of carbon fiber composite materials after the addition of an ultraviolet light absorber and a light stabilizer.

[0038] The easy-to-clean high-gloss varnish coating composition of the present invention has the characteristics of low-temperature curing, easy cleaning, recoatability, high transparency, beautiful appearance and chemical resistance, and can meet the application requirements of carbon fiber composite material automotive exterior parts. DETAILED DESCRIPTION

[0039] To more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments. It should be understood that the embodiments described are only a portion of the present invention, not all of the embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0040] In the following examples, the components of the composition are explained in parts by weight as a general standard. Unless otherwise specified, for the sake of simplicity, the "parts" in the examples of the present invention have the same meaning as parts by weight.

[0041] It should be noted that in the present invention, the easy-to-clean property of a clearcoat composition refers to the ability of the paint film to be easily cleaned by wiping or other simple methods after being contaminated by dust, oil, sweat, etc. This is different from traditional anti-graffiti properties, which refer to the resistance to leaving traces of contamination on the paint film. Therefore, even if an anti-graffiti additive is added to the formulation, the stain removal effect may not be obvious, and recoating problems may occur, which greatly affects the application of the coating in carbon fiber composites.

[0042] In order to obtain a two-component varnish coating composition that is easy to clean, has high gloss, has a low curing temperature and good recoatability, the present invention introduces a specific type of silicone-modified acrylic resin into the varnish coating composition formula. After addition, the addition can give the paint film good easy-to-clean performance. After reaction and curing with hydroxyl acrylic resin and isocyanate curing agent, the comprehensive performance of the paint film can be further improved, and there will be no recoating problem when coating on the surface of carbon fiber composite materials.

[0043] Specifically, the present invention provides an easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, wherein the varnish coating composition comprises component A and component B;

[0044] The component A comprises the following raw material components in parts by weight:

[0045] 20-80 parts of hydroxy acrylic resin, 3-30 parts of organosilicon-modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional additive;

[0046] The component B comprises the following raw material components in parts by weight:

[0047] 40-90 parts of isocyanate curing agent and 10-60 parts of a second solvent;

[0048] Wherein, the weight ratio of component A to component B is 1:10-10:1;

[0049] The organosilicon-modified acrylic resin is a modified resin formed by reacting a polyacrylate resin containing a hydroxyl functional group with an organosilicon oligomer containing a hydroxyl or alkoxy functional group.

[0050] The clearcoat coating composition provided by the present invention effectively decorates and protects the surface of carbon fiber composite materials, exhibiting high transparency and gloss, and imparting a clearly visible fiber texture to the carbon fiber composite materials. Furthermore, the clearcoat coating composition exhibits low-temperature curing, easy cleaning, excellent recoatability, and chemical resistance. Carbon fiber composite materials coated with the clearcoat coating composition can meet the requirements of applications such as automotive exterior trim.

[0051] Furthermore, the formula of component A was optimized, specifically including the following raw material components in parts by weight:

[0052] 30-50 parts of hydroxy acrylic resin, 5-20 parts of organosilicon modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional auxiliary agent.

[0053] Furthermore, the weight ratio of component A to component B is 1:5-5:1; illustratively, the weight ratio of component A to component B can be 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0054] Furthermore, the organosilicon-modified acrylic resin used in the present invention is a commercially available product with large hydrophobicity (water contact angle>100°), oleophobicity, and excellent solvent-resistant wiping performance. The paint film formed can be removed by simple methods such as wiping to remove pollutants adhering to the surface of the paint film, without the need for traditional high-pressure steam impact cleaning, thereby reducing the adverse effects of high-pressure steam impact on the paint film, making the cleaning method more convenient, and also ensuring the recoatability of the coating, which is difficult to achieve with many self-cleaning coatings currently available. For example, the organosilicon-modified acrylic resin includes but is not limited to the commercially available JZ-9522 and / or JZ-9540.

[0055] Furthermore, the hydroxy acrylic resin is polymerized from acrylic acid monomers, methacrylic acid monomers, and derivatives thereof, and is selected from commercially available hydroxy acrylic resins with a hydroxyl value of 0.5-8%. It has abundant active hydroxyl groups that can cross-link with other components of the varnish coating composition, thereby improving the adhesion of the paint film to the carbon fiber composite material. Furthermore, the hydroxy acrylic resin has good compatibility with additives and is easy to disperse. For example, the hydroxy acrylic resin includes, but is not limited to, one or more of Setalux 1907BA-75, TIRES 2850, SETALUX 1774SS-65, SETALUX 1215BA-68, and SETALUX 1274BA-70 from Allnex, Joncryl 507, Joncryl 804, and Joncryl 910 from BASF, and Hypomer MT-2550K, Hypomer MT-2550F, and Hypomer MT-2350 from Elementis.

[0056] Furthermore, the isocyanate curing agent includes, but is not limited to, one or more of aliphatic isocyanate polymers, alicyclic isocyanate polymers, aromatic isocyanate polymers, isocyanate hybrids, and isocyanate hybrid polymers. More specifically, the isocyanate curing agent can be any commercially available isocyanate curing agent that meets the above description, including but not limited to Desmodur N 3300, Desmodur N 3390, Desmodur N 3600, Desmodur N 3900, and Desmodur Z 4470 commercially available from Bayer MaterialScience, or HDT-90, HDT-100, and HDT-LV commercially available from Rhodia Group, or Basonat HI100 commercially available from BASF.

[0057] Furthermore, the first solvent and the second solvent may be the same or different, including but not limited to hexane, heptane, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, butyl acetate, ethyl acetate, 3-ethoxyethyl propionate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, propylene carbonate, dimethyl carbonate, No. 100 solvent oil, No. 150 solvent oil, No. 200 solvent oil, etc.

[0058] Furthermore, the ultraviolet light absorber includes but is not limited to one or more of Tinuvin 328, Tinuvin 384-2, Tinuvin 900, Tinuvin 928, Tinuvin 1130, Tinuvin 400, Tinuvin 479, Tinuvin 477, and Tinuvin CarboProtect.

[0059] Furthermore, the light stabilizer includes but is not limited to one or more of Tinuvin 144, Tinuvin 123, Tinuvin 292, Tinuvin 440 and Tinuvin 622.

[0060] Furthermore, the additional additives include one or more of a drier, a substrate wetting agent, a wetting and dispersing agent, a leveling agent, and a rheological additive. Those skilled in the art will appreciate that the additives can be selected based on actual process requirements, and the scope of other additives that can be used in the present invention is not limited to the additives listed above.

[0061] Furthermore, the component A may contain 0.01-0.5 parts of a drying agent; the component A may contain 0.01-0.5 parts of a substrate wetting agent; the component A may contain 0.01-0.5 parts of a wetting and dispersing agent; the component A may contain 0.01-1 parts of a leveling agent; and the component A may contain 0.1-1.0 parts of a rheological additive.

[0062] Furthermore, the viscosity of the varnish coating composition at 23° C. is in the range of 100-10000 mPa·s, preferably 100-5000 mPa·s.

[0063] The present invention also provides a method for preparing the above-mentioned varnish coating composition, comprising the steps of:

[0064] (1) Preparation of component A

[0065] Under stirring, 20-80 parts of hydroxy acrylic resin, 3-30 parts of silicone-modified acrylic resin, 0.1-3 parts of an external additive, 0.5-3 parts of an ultraviolet light absorber, and 0.5-2 parts of a light stabilizer are added to a first container, and 10-35 parts of a first solvent is provided for dispersion, and stirred until uniformly mixed to obtain the component A;

[0066] (2) Preparation of component B

[0067] Under stirring, adding 40-90 parts of an isocyanate curing agent to a second container and providing 10-60 parts of a second solvent for dispersion, wherein the second solvent is pre-filled with an inert gas to eliminate the influence of oxygen, and stirring until the mixture is uniformly mixed to obtain the component B;

[0068] (3) Component A and component B are fully mixed in a weight ratio of 1:10 to 10:1 to obtain the varnish coating composition.

[0069] The present invention also provides a surface treatment method, which comprises coating at least one layer of the varnish coating composition of the present invention as described above on at least one surface of the carbon fiber composite material, especially on an epoxy-based carbon fiber composite material substrate, curing the mixture at 60-90°C for 40-80 minutes, and repeating the above coating and curing operations 1-4 times to obtain an easy-to-clean, high-gloss varnish coating.

[0070] Furthermore, the coating formed by the single coating has a thickness of 40-60 μm; and the dry film thickness of the easy-to-clean high-gloss varnish coating is 100-200 μm.

[0071] Furthermore, the coating method is selected from air spraying, airless spraying, online electrostatic spraying or in-mold coating.

[0072] The following will provide further details through specific examples.

[0073] Example 1

[0074] In this embodiment, a clear varnish coating composition 1 having high gloss and easy cleaning properties is provided. The clear varnish coating composition 1 having high gloss and easy cleaning properties comprises component A and component B. The compositions of component A and component B are as follows, in parts by weight:

[0075] Table 1.1 Composition of component A in Example 1

[0076]

[0077] Table 1.2 Composition of component B in Example 1

[0078]

[0079]

[0080] The specific steps of the preparation method and application of the easy-to-clean high-gloss varnish coating composition 1 are as follows:

[0081] (1) Add SETALUX 1774SS-65, JZ-9540, butyl acetate and propylene glycol methyl ether acetate are stirred for 15-20 minutes at a stirring rate of 500-1500 rpm to mix uniformly. Then, Tego wet 270, BYK-315N, Tinuvin 1130 and Tinuvin 292 are added and stirring is continued for 20-30 minutes to obtain component A. The viscosity of component A at 23°C is 500-1000 mPa·s.

[0082] (2) Nitrogen was charged into a composite solvent of butyl acetate and propylene glycol methyl ether acetate, and Desmodur N 3390 was added under stirring. The mixture was stirred for 10-20 minutes to obtain component B. The mass percentage of the isocyanate curing agent in component B was 70%.

[0083] (3) When in use, component A and component B are fully mixed in a weight ratio of 3:1 to obtain the easy-to-clean high-gloss varnish coating composition 1.

[0084] The easy-to-clean high-gloss varnish coating composition 1 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain a varnish coating having a dry film thickness of 40-50 μm. Performance testing was then performed, and the relevant results are shown in Table 6.

[0085] Example 2

[0086] In this embodiment, an easy-to-clean high-gloss varnish coating composition 2 is provided. The easy-to-clean high-gloss varnish coating composition 2 includes component A and component B. The compositions of component A and component B are as follows, in parts by weight:

[0087] Table 2.1 Composition of Component A in Example 2

[0088]

[0089] Table 2.2 Composition of component B in Example 2

[0090] Components name Number of copies Isocyanate curing agent Desmodur N 3390 70 Second solvent 1 Butyl acetate 15 Second solvent 2 Propylene glycol methyl ether acetate 15

[0091] The specific steps of the preparation method and application of the easy-to-clean high-gloss varnish coating composition 2 are as follows:

[0092] (1) Add SETALUX 1774SS-65, JZ-9540, butyl acetate and propylene glycol methyl ether acetate are stirred for 15-20 minutes at a stirring rate of 500-1500 rpm to mix uniformly. Then, Tego wet 270, BYK-315N, Tinuvin 1130 and Tinuvin 292 are added and stirring is continued for 20-30 minutes to obtain component A. The viscosity of component A at 23°C is 500-1000 mPa·s.

[0093] (2) Nitrogen was charged into a composite solvent of butyl acetate and propylene glycol methyl ether acetate, and Desmodur N 3390 was added under stirring, and stirred for 10-20 minutes to obtain component B. The mass percentage of the isocyanate curing agent in component B was 70%.

[0094] (3) When in use, component A and component B are fully mixed in a weight ratio of 3:1 to obtain the easy-to-clean high-gloss varnish coating composition 2.

[0095] The easy-to-clean high-gloss varnish coating composition 2 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain an easy-to-clean high-gloss varnish coating having a dry film thickness of 40-50 μm. Performance testing was then performed, and the relevant results are shown in Table 6.

[0096] Comparative Example 1

[0097] In this comparative example, a varnish coating composition 1 is provided. The varnish coating composition 1 comprises component A and component B. The compositions of component A and component B are as follows, in parts by weight:

[0098] Table 3.1 Composition of component A in comparative example 1

[0099]

[0100] Table 3.2 Composition of component B in comparative example 1

[0101] Components name Number of copies Isocyanate curing agent Desmodur N 3390 70 Second solvent 1 Butyl acetate 15 Second solvent 2 Propylene glycol methyl ether acetate 15

[0102] The specific steps of the preparation method of the above-mentioned varnish coating composition 1 are as follows:

[0103] (1) Add SETALUX 1774SS-65, JZ-9540, butyl acetate and propylene glycol methyl ether acetate are stirred for 15-20 minutes at a stirring rate of 500-1500 rpm to mix uniformly. Then, Tego wet 270, BYK-315N, Tinuvin 1130 and Tinuvin 292 are added and stirring is continued for 20-30 minutes to obtain component A. The viscosity of component A at 23°C is 500-1000 mPa·s.

[0104] (2) Nitrogen was charged into a composite solvent of butyl acetate and propylene glycol methyl ether acetate, and Desmodur N 3390 was added under stirring. The mixture was stirred for 10-20 minutes to obtain component B. The mass percentage of the isocyanate curing agent in component B was 70%.

[0105] (3) When in use, component A and component B are fully mixed in a weight ratio of 3:1 to obtain the varnish coating composition 1.

[0106] The varnish coating composition 1 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain a varnish coating having a dry film thickness of 40-50 μm. The performance test was then performed, and the relevant results are shown in Table 6.

[0107] Example 3

[0108] In this embodiment, an easy-to-clean high-gloss varnish coating composition 3 is provided. The easy-to-clean high-gloss varnish coating composition 3 includes component A and component B. The compositions of component A and component B are as follows, in parts by weight:

[0109] Table 4.1 Composition of Component A in Example 3

[0110]

[0111] Table 4.2 Composition of component B in Example 3

[0112] Components name Number of copies Isocyanate curing agent Desmodur N 3390 70 Second solvent 1 Butyl acetate 15 Second solvent 2 Propylene glycol methyl ether acetate 15

[0113] The specific steps of the preparation method of the easy-to-clean high-gloss varnish coating composition 3 are as follows:

[0114] (1) Add SETALUX 1774SS-65, JZ-9522, butyl acetate, and propylene glycol methyl ether acetate are stirred for 15-20 minutes at a stirring rate of 500-1500 rpm to uniformly mix. Then, Tego wet 270, BYK-315N, Tinuvin 1130, and Tinuvin 292 are added and stirring is continued for 20-30 minutes to obtain component A. The viscosity of component A at 23°C is 500-1000 mPa·s.

[0115] (2) Nitrogen was charged into a composite solvent of butyl acetate and propylene glycol methyl ether acetate, and Desmodur N 3390 was added under stirring, and stirred for 10-20 minutes to obtain component B. The mass percentage of the isocyanate curing agent in component B was 70%.

[0116] (3) When in use, component A and component B are fully mixed in a weight ratio of 3:1 to obtain the easy-to-clean high-gloss varnish coating composition 3.

[0117] The easy-to-clean high-gloss varnish coating composition 3 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain a varnish coating having a dry film thickness of 40-50 μm. Performance testing was then performed, and the relevant results are shown in Table 6.

[0118] Comparative Example 2

[0119] In this comparative example, a varnish coating composition 2 is provided, which comprises component A and component B, wherein, by weight, the compositions of component A and component B are as follows:

[0120] Table 5.1 Composition of component A in comparative example 2

[0121]

[0122] Table 5.2 Composition of component B in comparative example 2

[0123] Components name Number of copies Isocyanate curing agent Desmodur N 3390 70 Second solvent 1 Butyl acetate 15 Second solvent 2 Propylene glycol methyl ether acetate 15

[0124] It should be noted that: in this example, component A contains only hydroxy acrylic resin and does not contain silicone modified acrylic resin. Its easy-to-clean effect is mainly achieved by adding anti-graffiti additives. Protect 5000N is achieved, so it is not within the scope of the present invention and is therefore used as Comparative Example 2.

[0125] The specific steps of the preparation method of the above-mentioned varnish coating composition 2 are as follows:

[0126] (1) Add SETALUX 1774SS-65, butyl acetate and propylene glycol methyl ether acetate to the main container in sequence under stirring, stir for 15-20 minutes, and control the stirring rate at 500-1500 rpm. After mixing evenly, add Protect 5000N, stir for 15-20 minutes at a stirring rate of 500-1500 rpm. Once thoroughly mixed, add Tego wet 270, BYK-315N, Tinuvin 1130, and Tinuvin 292 and continue stirring for 20-30 minutes to obtain Component A. The viscosity of Component A at 23°C is 500-1000 mPa·s.

[0127] (2) Nitrogen was charged into a composite solvent of butyl acetate and propylene glycol methyl ether acetate, and Desmodur N 3390 was added under stirring, and stirred for 10-20 minutes to obtain component B. The mass percentage of the isocyanate curing agent in component B was 70%.

[0128] (3) When in use, component A and component B are fully mixed in a weight ratio of 3:1 to obtain the varnish coating composition 2.

[0129] The varnish coating composition 2 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain a varnish coating having a dry film thickness of 40-50 μm. The performance test was then performed, and the relevant results are shown in Table 6.

[0130] Comparative Example 3

[0131] In this comparative example, a varnish coating composition 3 is provided, which is a commercially available nano self-cleaning varnish product (NOVclean TM Self-cleaning nano coating), the product is a single component.

[0132] The varnish coating composition 3 was applied to an epoxy-based carbon fiber composite substrate coated with a transparent primer and cured at 80°C for 60 minutes to obtain a varnish coating having a dry film thickness of 5-10 μm. The performance test was then performed, and the relevant results are shown in Table 6.

[0133] Comparison results

[0134] In this embodiment, the easy-to-clean high-gloss varnish coating composition 1 of Example 1, the easy-to-clean high-gloss varnish coating composition 2 of Example 2, the easy-to-clean high-gloss varnish coating composition 3 of Example 3, the varnish coating composition 1 of Comparative Example 1, the varnish coating composition 2 of Comparative Example 2, and the varnish coating composition 3 of Comparative Example 3 are compared.

[0135] The performance test results of each sample are shown in Table 6.

[0136] Table 6 Performance test results of each coating composition on carbon fiber composite material samples

[0137]

[0138] The easy-to-clean effect is achieved by writing on the coating surface with an oil-based marker and then wiping it directly with a non-woven fabric. The applicant used a carbon fiber composite material sample as a substrate to prepare the above coatings (Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3) with the same film thickness to compare the easy-to-clean effects of the above coatings.

[0139] The results in Table 6 show that Examples 1-3 performed similarly to Comparative Examples 1-2 in terms of gloss, pencil hardness, substrate adhesion, gasoline resistance, and light aging resistance. However, since Comparative Example 3 failed to fully cure at 80°C for 60 minutes, the resulting coatings exhibited poor hardness, gloss, and substrate adhesion, making gasoline resistance and light aging resistance untestable. In terms of easy-to-clean performance, Examples 1-3 and Comparative Example 2 significantly outperformed Comparative Example 3, also due to poor film formation under these curing conditions. However, Comparative Examples 1-3 exhibited poor recoat adhesion. Examples 1-2 and Comparative Example 1 demonstrate that increasing the amount of organosilicon-modified acrylic resin improves the easy-to-clean performance. However, after reaching a certain level, recoat adhesion fails to meet requirements. Therefore, the amount of organosilicon-modified acrylic resin needs to be properly controlled to achieve a balance between easy-to-clean performance and recoat adhesion. Furthermore, Comparative Example 2 demonstrates that anti-graffiti additives significantly affect the recoatability of the paint film, making them unsuitable for the multi-coating requirements of carbon fiber.

[0140] The present invention is described in this specification as a preferred embodiment of the present invention. The above embodiment is intended to illustrate the technical solutions of the present invention and is not intended to limit the present invention. Any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning, or limited experimentation based on the concept of the present invention shall be within the scope of protection of the present invention.

Claims

1. An easy-to-clean high-gloss varnish coating composition for surface coating of carbon fiber composite materials, characterized in that: The clearcoat coating composition comprises component A and component B; The component A comprises the following raw material components in parts by weight: 60-80 parts of hydroxy acrylic resin, 3-10 parts of organosilicon-modified acrylic resin, 10-35 parts of a first solvent, 0.5-3 parts of an ultraviolet light absorber, 0.5-2 parts of a light stabilizer, and 0.1-3 parts of an additional additive; The component B comprises the following raw material components in parts by weight: 70-90 parts of isocyanate curing agent and 10-60 parts of a second solvent; Wherein, the weight ratio of component A to component B is 1:10-10:1; The hydroxy acrylic resin is selected from SETALUX 1774 SS-65 of Allnex Company; The organosilicon-modified acrylic resin is selected from JZ-9522 and / or JZ-9540 commercially available from JZ-Sino Corporation; The isocyanate curing agent is selected from Desmodur N 3390.

2. The clear coating composition according to claim 1, characterized in that The weight ratio of component A to component B is 1:5-5:

1.

3. The clear coating composition according to claim 1, characterized in that The first solvent and the second solvent are independently selected from one or more of hexane, heptane, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, butyl acetate, ethyl acetate, 3-ethoxyethyl propionate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, propylene carbonate, dimethyl carbonate, No. 100 solvent oil, No. 150 solvent oil, and No. 200 solvent oil.

4. The clear coating composition according to claim 1, wherein The additional additives include one or more of a drying agent, a substrate wetting agent, a wetting and dispersing agent, a leveling agent, and a rheological additive.

5. The clear coating composition according to claim 1, characterized in that The viscosity of the clear coating composition at 23° C. is in the range of 100-10000 mPa·s.

6. The clear coating composition according to claim 1, characterized in that The viscosity of the clear coating composition at 23° C. is in the range of 100-5000 mPa·s.

7. The method for preparing the clear coating composition according to any one of claims 1 to 6, wherein: The following steps are included: (1) Adding a hydroxy acrylic resin, a silicone-modified acrylic resin, an additional additive, an ultraviolet light absorber, a light stabilizer, and a first solvent to a first container under stirring, and stirring until the mixture is uniformly mixed to obtain the component A; (2) adding an isocyanate curing agent and a second solvent to a second container under stirring, and stirring until the mixture is uniform to obtain the component B; (3) Component A and component B are mixed in proportion to obtain the varnish coating composition.

8. A surface treatment method, characterized in that: The surface treatment method comprises coating at least one layer of the varnish coating composition according to any one of claims 1 to 6 on at least one surface of the carbon fiber composite material.

9. The surface treatment method according to claim 8, characterized in that: The coating method is selected from air spraying, airless spraying, online electrostatic spraying or in-mold coating.

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