A high temperature resistant high gloss clear coating composition, a method of making the same, and a high temperature resistant high gloss clear coating layer made therefrom

Abstract

The application provides a high-temperature-resistant high-gloss varnish coating composition, a preparation method thereof and a high-temperature-resistant high-gloss varnish coating prepared by the method. The high-temperature-resistant high-gloss varnish coating composition comprises component A and component B; the component A comprises 50-80 parts of a hydroxyl resin, 10-35 parts of a first solvent, 0.1-2 parts of a thermal stability aid, 0.5-3 parts of an ultraviolet light absorber and 0.5-2 parts of a light stabilizer in terms of weight parts; the component B comprises 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent; and the weight ratio of the component A to the component B is 1:10-20:1. The coating obtained by using the coating composition provided by the application has the properties of high-temperature resistance, high transparency, high gloss, chemical corrosion resistance and high weather resistance, and the carbon fiber composite material coated by the coating can meet the application requirements of automobile exterior parts and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of surface coating of carbon fiber composite materials, and particularly comprises a high-temperature-resistant high-gloss varnish coating composition, a preparation method thereof, and a high-temperature-resistant high-gloss varnish coating prepared therefrom. BACKGROUND

[0002] As a high-strength, high-rigidity lightweight material, carbon fiber composite materials (CFRP) are increasingly becoming one of the most popular lightweight materials in the fields of automobiles, rail vehicles, sports equipment, etc. When used for exterior parts of rail vehicles, automobiles, etc., carbon fiber composite materials generally need to be coated to achieve the purposes of aesthetics and protection of the substrate. In order to present the special texture weaving effect of carbon fibers, high-gloss varnish transparent coatings are mostly used in the prior art for coating carbon fiber composite materials. With the expansion of the application range, the performance requirements of high-gloss varnish transparent coatings on carbon fiber composite material coating are becoming higher and higher.

[0003] For carbon fiber automobiles, some exterior or interior parts are used in high-temperature environments, such as automobile hubs, engine covers, exhaust pipes, etc. Therefore, when such carbon fiber parts of automobiles are applied, the varnish coating is required to have high-temperature resistance. At present, high-gloss varnish coatings applied to carbon fiber coating on the market are prone to yellowing, wrinkling, cracking, delamination, etc. under high-temperature environments. In addition, the transparent varnish coating on the surface of carbon fiber composite materials must be able to improve the weather resistance of the substrate, thereby protecting the carbon fiber composite materials, especially epoxy-based carbon fiber composite materials, from yellowing. Although some functional additives that can improve the thermal performance of coatings have been reported, it is found in actual application that the introduction of these functional additives may bring about adverse effects such as reduced transparency and gloss, and there are also certain compatibility problems when different resin systems are used with these functional additives.

[0004] Therefore, how to develop a high-temperature-resistant high-gloss varnish coating composition that can be more efficiently and conveniently used for surface coating of carbon fiber composite materials, so as to achieve high-gloss varnish effects for carbon fiber composite materials while having excellent high-temperature resistance, high transparency, high gloss, chemical corrosion resistance, and high weather resistance, thereby eliminating the above-mentioned defects and shortcomings in the prior art and better serving the needs of exterior paint surfaces of vehicles, etc., is an urgent issue for relevant technical personnel in the industry. SUMMARY

[0005] In view of the above problems existing in the prior art, the first object of the present application is to provide a high-temperature-resistant high-gloss varnish coating composition for carbon fiber composite materials.

[0006] The second object of the present invention is to provide a method for preparing the high-temperature resistant high-gloss varnish coating composition as described above.

[0007] The third object of the present invention is to provide a high-temperature resistant high-gloss varnish coating prepared using the high-temperature resistant high-gloss varnish coating composition as described above.

[0008] To achieve the above first object, the technical solution adopted by the present invention includes:

[0009] The present invention discloses a high-temperature resistant high-gloss varnish coating composition for carbon fiber composite materials, comprising component A and component B;

[0010] In parts by weight, the component A comprises 50-80 parts of a hydroxyl resin, 10-35 parts of a first solvent, 0.1-2 parts of a heat stabilizing agent, 0.5-3 parts of an ultraviolet light absorber, and 0.5-2 parts of a light stabilizer; the component B comprises 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent;

[0011] The weight ratio of component A to component B is 1:10-20:1.

[0012] Furthermore, the heat stabilizing agent is selected from polyhydric hindered phenol antioxidants and / or organic phosphate antioxidants.

[0013] Furthermore, the heat stabilizing agent is selected from one or more of Irganox 1010, Irganox 1076, RIANOX 1010, RIANOX 1076, RIANOX 1098, IRGAFOS 168, and RIANOX 168.

[0014] Furthermore, the hydroxy resin is selected from one or more of hydroxyl-containing acrylic resin, hydroxyl-containing polyester resin, and hydroxyl-containing silicone resin; preferably, hydroxyl-containing acrylic resin and / or hydroxyl-containing silicone resin.

[0015] The isocyanate curing agent is selected from one or more of aliphatic isocyanate monomers, aliphatic isocyanate polymers, alicyclic isocyanate monomers, alicyclic isocyanate polymers, aromatic isocyanate monomers, aromatic isocyanate polymers, isocyanate hybrids, and isocyanate hybrid polymers.

[0016] Further, the first solvent and the second solvent are the same or different, and are each 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.

[0017] Furthermore, the component A further comprises 0.1-2 parts of other auxiliary agents;

[0018] The other additives are selected from one or more of a drying agent, a substrate wetting agent, a wetting and dispersing agent, a leveling agent, and a rheological additive.

[0019] Furthermore, the viscosity of the high-temperature resistant high-gloss varnish coating composition at 23° C. is in the range of 100-20,000 mPa·s; preferably 100-10,000 mPa·s; and more preferably 100-5,000 mPa·s.

[0020] To achieve the above second purpose, the technical solutions adopted by the present invention include:

[0021] The present invention discloses a method for preparing the high-temperature resistant high-gloss varnish coating composition as described above, comprising the following steps:

[0022] (1) adding a hydroxy resin, a heat stabilizing agent, an ultraviolet light absorber, a light stabilizer, and a first solvent to a container A under stirring, and mixing them uniformly to obtain the component A;

[0023] (2) adding an isocyanate curing agent and a second solvent to a container B under stirring, and mixing them uniformly to obtain the component B;

[0024] (3) Component A and component B are mixed in proportion to obtain the high-temperature resistant high-gloss varnish coating composition.

[0025] To achieve the third objective, the present invention employs the following technical solutions:

[0026] The invention discloses a high-temperature resistant high-gloss varnish coating, which is obtained by coating at least one layer of the high-temperature resistant high-gloss varnish coating composition described above on at least one surface of a carbon fiber composite material.

[0027] Furthermore, the coating method is selected from air spraying, airless spraying, online electrostatic spraying or in-mold coating.

[0028] Beneficial effects of the present invention:

[0029] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0030] The high-temperature resistant high-gloss varnish coating composition of the present invention can give the carbon fiber composite material high transparency and an aesthetically pleasing high-gloss varnish effect, and enables the carbon fiber composite material to meet the high-temperature resistance performance requirements of automobile exteriors.

[0031] The high-temperature resistant 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.

[0032] The high-temperature resistant high-gloss varnish coating composition of the present invention has the characteristics of high gloss, low-temperature rapid curing, chemical corrosion resistance, etc., and can meet the application requirements of carbon fiber composite materials such as automotive exterior parts. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] The first aspect of the present invention provides a high-temperature resistant high-gloss clearcoat coating composition for carbon fiber composite materials. By introducing a heat stabilizing additive into a two-component coating formulation, the high-temperature resistance of the resulting coating is improved. The specific formula of the high-temperature resistant high-gloss clearcoat coating composition is:

[0036] Contains component A and component B;

[0037] In parts by weight, the component A comprises 50-80 parts of a hydroxyl resin, 10-35 parts of a first solvent, 0.1-2 parts of a heat stabilizing agent, 0.5-3 parts of an ultraviolet light absorber, and 0.5-2 parts of a light stabilizer; the component B comprises 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent;

[0038] The weight ratio of component A to component B is 1:10-20:1.

[0039] Furthermore, the heat stabilizing agent is selected from a polyfunctional hindered phenol antioxidant and / or an organic phosphate antioxidant; although these heat stabilizing agents currently reported can improve the heat resistance of the coating to a certain extent, they may also sacrifice a certain degree of transparency and gloss. Considering the application scenarios of the high-temperature resistant high-gloss varnish coating composition of the present invention, the requirements for performance such as transparency and gloss are also very high, so it is necessary to screen out heat stabilizing agents that are suitable for the application requirements of the present invention and are adapted to the coating system of the present invention. After a large number of experimental studies by the inventors, when the heat stabilizing agent is selected from one or more of Irganox 1010, Irganox 1076, RIANOX 1010, RIANOX 1076, RIANOX 1098, IRGAFOS168, and RIANOX168, the prepared varnish coating has better comprehensive performance. Preferably, the amount of the heat stabilizing agent in component A may be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1.0 part, 1.1 part, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2.0 parts, etc.

[0040] Furthermore, the hydroxyl resin is selected from one or more of a hydroxyl-containing acrylic resin, a hydroxyl-containing polyester resin, and a hydroxyl-containing silicone resin. Experiments have found that for the coating composition formula provided by the present invention, when the hydroxyl resin is selected from a hydroxyl-containing acrylic resin and / or a hydroxyl-containing silicone resin, the overall performance of the coating obtained is better.

[0041] Furthermore, the hydroxyl-containing acrylic resin is polymerized from acrylic acid monomers, methacrylic acid monomers, or derivatives thereof. For example, the hydroxyl-containing acrylic resin includes, but is not limited to, Setalux 1907BA-75, TIRES 2850, SETALUX 1774SS-65, SETALUX 1215BA-68, SETALUX 1274BA-70, SETALUX 91757VX-60, SETALUX 91795VX-60, SETALUX 61767VX-60, etc., commercially available from Allnex, or Joncryl 507, Joncryl 804, Joncryl 910, etc., commercially available from BASF.

[0042] Furthermore, the hydroxyl-containing silicone resin includes but is not limited to the commercially available silicone resins from EVONIK. E900, E 901, etc., or those sold by WACKER MSE 100, or the one sold by Jiazhi JZ-9522, JZ-9540, etc.

[0043] Furthermore, the hydroxyl-containing polyester resin includes, but is not limited to, conventional saturated polyester polyols, polycaprolactone polyols, polycarbonate diols, etc. For example, it can be SETAL 1612VS-60, SETAL 1715VX-74, SETAL 90173SS-50, SETAL 1603BA-78, SETAL 168SS-80, SETAL 82166SS-64, etc. commercially available from Allnex, or K-Flex XM-332, K-Flex 148, K-Flex XM-337, etc. commercially available from King Industries.

[0044] Further, the component A comprises 60-75 parts of hydroxyl resin; illustratively, it can be 60 parts, 60.5 parts, 61 parts, 61.5 parts, 62 parts, 62.5 parts, 63 parts, 63.5 parts, 64 parts, 64.5 parts, 65 parts, 65.5 parts, 66 parts, 66.5 parts, 67 parts, 67.5 parts, 68 parts, 68.5 parts, 69 parts, 69.5 parts, 70 parts, 70.5 parts, 71 parts, 71.5 parts, 72 parts, 72.5 parts, 73 parts, 73.5 parts, 74 parts, 74.5 parts or 75 parts, and the like.

[0045] Furthermore, the isocyanate curing agent includes but is not limited to one or more of aliphatic isocyanate monomers, aliphatic isocyanate polymers, alicyclic isocyanate monomers, alicyclic isocyanate polymers, aromatic isocyanate monomers, aromatic isocyanate polymers, isocyanate hybrids, and isocyanate hybrid polymers.

[0046] Furthermore, the aliphatic isocyanate monomer includes but is not limited to one or more of tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, 2,2,4-trimethylhexane 1,6-diisocyanate, ethylene diisocyanate, and 1,12-dodecane diisocyanate.

[0047] Furthermore, the aliphatic isocyanate polymer is an aliphatic isocyanate dimer and / or an aliphatic isocyanate trimer.

[0048] Furthermore, the alicyclic isocyanate monomer includes but is not limited to one or more of isophorone diisocyanate, cyclobutane 1,3-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, methylcyclohexyl diisocyanate, 4,4'-methylene dicyclohexyl diisocyanate, and hydrogenated diphenylmethane diisocyanate.

[0049] Furthermore, the alicyclic isocyanate polymer is an alicyclic isocyanate dimer and / or an alicyclic isocyanate trimer.

[0050] Furthermore, the aromatic isocyanate monomer includes but is not limited to one or more of toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, p-phenylene diisocyanate, biphenyl diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate, and hexahydrophenylene 1,3-diisocyanate.

[0051] Furthermore, the aromatic isocyanate polymer is an aromatic isocyanate dimer and / or an aromatic isocyanate trimer.

[0052] Furthermore, the isocyanate hybrid polymer is an isocyanate hybrid dimer and / or an isocyanate hybrid trimer.

[0053] Furthermore, 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 N3600, Desmodur N 3900, Desmodur Z 4470, etc. commercially available from Bayer MaterialScience, or HDT-90, HDT-100, HDT-LV, etc. commercially available from Rhodia Group, or Basonat HI100, etc. commercially available from BASF.

[0054] Further, the component A contains 50-80 parts of isocyanate curing agent; illustratively, it can be 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts or 80 parts, etc.

[0055] Furthermore, the UV 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. Preferably, component A contains 0.5-1.5 parts of the UV absorber; for example, it can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 parts.

[0056] 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. Preferably, component A contains 0.5-1.0 parts of light stabilizer; illustratively, it can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, or 1.0 parts, etc.

[0057] Furthermore, component A may further comprise 0.1-2 parts of other additives, including but not limited to one or more of a drier, a substrate wetting agent, a wetting and dispersing agent, a leveling agent, and a rheological additive. It will be appreciated by those skilled in the art that the additives may be selected based on actual process requirements, and the scope of other additives that may be used in the present invention is not limited to the additives listed above.

[0058] Furthermore, component A may contain 0.01-0.1 parts of a drying agent; component A may contain 0.01-0.3 parts of a substrate wetting agent; component A may contain 0.01-0.2 parts of a wetting and dispersing agent; component A may contain 0.01-0.5 parts of a leveling agent; and component A may contain 0.1-1.0 parts of a rheological additive.

[0059] 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.

[0060] Furthermore, the weight ratio of component A to component B is 1-2:1-2; illustratively, the weight ratio of component A to component B can be 1:1, 5:4, 5:3, 2:1, 4:5, 3:5, 1:2, etc.

[0061] The second aspect of the present invention provides a method for preparing the high-temperature resistant high-gloss varnish coating composition according to the first aspect of the present invention, comprising the steps of:

[0062] (1) Preparation of component A

[0063] Under stirring, add 50-80 parts of hydroxyl resin, 0.1-2 parts of heat stabilizing agent, 0.5-3 parts of ultraviolet light absorber, 0.5-2 parts of light stabilizer, 0.1-2 parts of other additives and 10-35 parts of the first solvent to container A, and mix well to obtain the component A;

[0064] (2) Preparation of component B

[0065] Under stirring, add 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent to container B, wherein the second solvent is pre-filled with an inert gas to eliminate the influence of oxygen, and mix well to obtain the component B;

[0066] (3) Component A and component B are fully mixed in a weight ratio of 1:10 to 20:1 to obtain the high-temperature resistant high-gloss varnish coating composition.

[0067] Furthermore, the viscosity of the high-temperature resistant high-gloss varnish coating composition at 23° C. is in the range of 100-20,000 mPa·s; preferably 100-10,000 mPa·s; and more preferably 100-5,000 mPa·s.

[0068] The third aspect of the present invention provides a high-temperature resistant high-gloss varnish coating prepared using the high-temperature resistant high-gloss varnish coating composition described in the first aspect of the present invention. The high-temperature resistant high-gloss varnish coating composition is applied to at least one surface of a carbon fiber composite material, especially an epoxy-based carbon fiber composite material substrate, and cured at 60-90°C for 40-80 minutes. The above coating and curing operations are repeated 1-4 times to obtain a high-temperature resistant high-gloss varnish coating.

[0069] Furthermore, the coating formed by the single coating has a thickness of 40-60 μm; and the dry film thickness of the high-temperature resistant high-gloss varnish coating is 100-200 μm.

[0070] The specific embodiments of the present invention are described in detail below.

[0071] Example 1

[0072] In this embodiment, a high-temperature resistant high-gloss varnish coating composition is provided. The high-temperature resistant high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 1.1 and Table 1.2.

[0073] Table 1.1 Composition of component A in Example 1

[0074] Components name Number of copies Hydroxyl resin SETALUX 1774 SS-65 69.5 Heat stabilizing additives Irganox 1076 0.5 First solvent 1 Butyl acetate 18 First solvent 2 Xylene 10 Substrate wetting agents Tego Wet 270 0.3 Leveling agent BYK-315N 0.2 UV absorbers Tinuvin 400 1 Light stabilizers Tinuvin 123 0.5

[0075] Table 1.2 Composition of component B in Example 1

[0076] 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

[0077] The specific steps of the preparation method and application of the above-mentioned high-temperature resistant high-gloss varnish coating composition are as follows:

[0078] (1) Under stirring, add SETALUX 1774SS-65, Irganox 1076, butyl acetate and xylene to the main container in sequence, stir for 15-20 minutes, and control the stirring rate at 500-1500 rpm to mix them evenly. Then add TegoWet 270, BYK-315N, Tinuvin 400 and Tinuvin 123 and continue stirring for 20-30 minutes to obtain component A.

[0079] (2) In another container, butyl acetate and propylene glycol methyl ether acetate were added while stirring, and nitrogen was introduced. Desmodur N 3390 was added and stirred for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0080] (3) When in use, component A and component B are fully mixed in a weight ratio of 2:1 to obtain the high-temperature resistant high-gloss varnish coating composition with a viscosity of 100 mPa.s / 23°C.

[0081] (4) The high-temperature resistant high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0082] Example 2

[0083] In this embodiment, a high-temperature resistant high-gloss varnish coating composition is provided. The high-temperature resistant high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 2.1 and Table 2.2.

[0084] Table 2.1 Composition of Component A in Example 2

[0085] Components name Number of copies Hydroxyl resin SETAL 168 SS-80 69.5 Heat stabilizing additives Irganox 1076 0.5 First solvent 1 Butyl acetate 18 First solvent 2 Xylene 10 Substrate wetting agents Tego Wet 270 0.3 Leveling agent BYK-315N 0.2 UV absorbers Tinuvin 400 1 Light stabilizers Tinuvin 123 0.5

[0086] Table 2.2 Composition of component B in Example 2

[0087] 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

[0088] The specific steps of the preparation method and application of the above-mentioned high-temperature resistant high-gloss varnish coating composition are as follows:

[0089] (1) Under stirring, add SETAL 168SS-80, Irganox 1076, butyl acetate and xylene to the main container in sequence and stir for 15-20 minutes at a stirring rate of 500-1500 rpm to mix them evenly. Then add Tego Wet 270, BYK-315N, Tinuvin 400 and Tinuvin 123 and continue stirring for 20-30 minutes to obtain component A.

[0090] (2) In another container, butyl acetate and propylene glycol methyl ether acetate were added while stirring, and nitrogen was introduced. The isocyanate curing agent Desmodur N 3390 was added and stirred for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0091] (3) When in use, component A and component B are fully mixed in a weight ratio of 5:3 to obtain the high-temperature resistant high-gloss varnish coating composition with a viscosity of 150 mPa.s / 23°C.

[0092] (4) The high-temperature resistant high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0093] Example 3

[0094] In this embodiment, a high-temperature resistant high-gloss varnish coating composition is provided. The high-temperature resistant high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 3.1 and Table 3.2.

[0095] Table 3.1 Composition of Component A in Example 3

[0096]

[0097]

[0098] Table 3.2 Composition of component B in Example 3

[0099] 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

[0100] The specific steps of the preparation method and application of the above-mentioned high-temperature resistant high-gloss varnish coating composition are as follows:

[0101] (1) Add the following to the main container in sequence while stirring: E 901, Irganox 1076, butyl acetate, and xylene are stirred for 15-20 minutes at a stirring rate of 500-1500 rpm to mix uniformly. Then, TegoWet 270, BYK-315N, Tinuvin 400, and Tinuvin 123 are added and stirring is continued for 20-30 minutes to obtain component A.

[0102] (2) In another container, butyl acetate and propylene glycol methyl ether acetate were added while stirring, and nitrogen was introduced. Desmodur N 3390 was added and stirred for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0103] (3) When in use, component A and component B are fully mixed in a weight ratio of 5:4 to obtain the high-temperature resistant high-gloss varnish coating composition with a viscosity of 150 mPa.s / 23°C.

[0104] (4) The high-temperature resistant high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0105] Example 4

[0106] In this embodiment, a high-temperature resistant high-gloss varnish coating composition is provided. The high-temperature resistant high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 4.1 and Table 4.2.

[0107] Table 4.1 Composition of Component A in Example 4

[0108]

[0109] Table 4.2 Composition of component B in Example 4

[0110] 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

[0111] The specific steps of the preparation method and application of the above-mentioned high-temperature resistant high-gloss varnish coating composition are as follows:

[0112] (1) Under stirring, add SETALUX 1774SS-65, RIANOX 168, butyl acetate and xylene into the main container in sequence, stir for 15-20 minutes, and control the stirring rate at 500-1500 rpm to mix them evenly. Then add Tego Wet 270, BYK-315N, Tinuvin 400 and Tinuvin 123 and continue stirring for 20-30 minutes to obtain component A.

[0113] (2) In another container, butyl acetate and propylene glycol methyl ether acetate were added while stirring, and nitrogen was introduced. The isocyanate curing agent Desmodur N 3390 was added and stirred for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0114] (3) When in use, component A and component B are fully mixed in a weight ratio of 2:1 to obtain the high-temperature resistant high-gloss varnish coating composition with a viscosity of 100 mPa.s / 23°C.

[0115] (4) The high-temperature resistant high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0116] Comparative Example 1

[0117] In this comparative example, a high-gloss varnish coating composition is provided. The high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 5.1 and Table 5.2.

[0118] Table 5.1 Composition of component A in comparative example 1

[0119] Components name Number of copies Hydroxyl resin SETALUX 1774 SS-65 65 Heat stabilizing additives Irganox 1076 5 First solvent 1 Butyl acetate 18 First solvent 2 Xylene 10 Substrate wetting agents Tego Wet 270 0.3 Leveling agent BYK-315N 0.2 UV absorbers Tinuvin 400 1 Light stabilizers Tinuvin 123 0.5

[0120] Table 5.2 Composition of component B in comparative example 1

[0121] 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

[0122] The specific steps of the preparation method and application of the above-mentioned high-gloss varnish coating composition are as follows:

[0123] (1) Under stirring, add SETALUX 1774SS-65, Irganox 1076, butyl acetate and xylene to the main container in sequence, stir for 15-20 minutes, and control the stirring rate at 500-1500 rpm to mix them evenly. Then add TegoWet 270, BYK-315N, Tinuvin 400 and Tinuvin 123 and continue stirring for 20-30 minutes to obtain component A.

[0124] (2) In another container, butyl acetate and propylene glycol methyl ether acetate were added while stirring, and nitrogen was introduced. The isocyanate curing agent Desmodur N 3390 was added and stirred for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0125] (3) When in use, component A and component B are fully mixed in a weight ratio of 2:1 to obtain the high gloss varnish coating composition having a viscosity of 120 mPa.s / 23°C.

[0126] (4) The high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0127] Comparative Example 2

[0128] In this comparative example, a high-gloss varnish coating composition is provided. The high-gloss varnish coating composition includes component A and component B. The compositions of component A and component B in parts by weight are shown in Table 6.1 and Table 6.2.

[0129] Table 6.1 Composition of component A in comparative example 2

[0130] Components name Number of copies Hydroxyl resin SETALUX 1774 SS-65 69.5 Heat stabilizing additives Tribasic lead sulfate 0.5 First solvent 1 Butyl acetate 18 First solvent 2 Xylene 10 Substrate wetting agents Tego Wet 270 0.3 Leveling agent BYK-315N 0.2 UV absorbers Tinuvin 400 1 Light stabilizers Tinuvin 123 0.5

[0131] Table 6.2 Composition of component B in comparative example 2

[0132] 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

[0133] The specific steps of the preparation method and application of the above-mentioned high-gloss varnish coating composition are as follows:

[0134] (1) Add SETALUX 1774SS-65, tribasic lead sulfate, butyl acetate, and xylene to the main container in sequence while stirring. Stir for 15-20 minutes at a rate of 500-1500 rpm. After uniform mixing, add TegoWet 270, BYK-315N, Tinuvin 400, and Tinuvin 123. Continue stirring for 20-30 minutes to obtain component A.

[0135] While stirring, add butyl acetate and propylene glycol methyl ether acetate to another container, fill with nitrogen, add isocyanate curing agent Desmodur N 3390, and stir for 10-20 minutes at a stirring rate of 300-1000 rpm to obtain component B.

[0136] (3) When in use, component A and component B are fully mixed in a weight ratio of 2:1 to obtain the high gloss varnish coating composition having a viscosity of 150 mPa.s / 23°C.

[0137] (4) The high-gloss varnish coating composition was applied to the epoxy-based carbon fiber composite material substrate and cured at 80°C for 60 min. The above coating and curing operations were repeated twice to obtain a high-temperature resistant high-gloss varnish coating with a dry film thickness of 150 μm. The relevant results are shown in Table 7.

[0138] Table 7 Performance test results of each coating composition on carbon fiber composite material samples

[0139]

[0140] Comparing the performance of Examples 1-4, hydroxyl-containing polyester resins perform inferior to hydroxyl-containing acrylic resins and hydroxyl-containing silicone resins in terms of pencil hardness and 92# gasoline resistance, failing to meet the requirements. Comparing Comparative Example 1 with Examples 1 and 4 demonstrates that exceeding a certain limit in the amount of thermal stabilizer can negatively impact the hardness and adhesion of the paint film. Comparing Comparative Example 2 with Examples 1-4 demonstrates that the commonly used thermal stabilizer (tribasic lead sulfate) is incompatible with the high-gloss clearcoat system of this invention, affecting the paint film's gloss, transparency, appearance, gasoline resistance, and other properties. Secondly, in terms of long-term high temperature resistance (90°C / 1000 hours) and short-term high temperature resistance (150°C / 2 hours), Example 3 and Example 4 are the best, followed by Example 1, then Example 2 and Comparative Example 1, and the worst is Comparative Example 2. This shows that: first, the addition of heat stabilizing agents helps to improve high temperature resistance; second, in terms of high temperature resistance, hydroxyl-containing silicone resin>hydroxyl-containing acrylic resin>hydroxyl-containing polyester resin, and the addition of hydroxyl-containing polyester resin makes it more difficult for the coating to meet the high temperature resistance requirements; third, the heat stabilizing agents commonly used in the market are not suitable for the high-gloss varnish system of the invention, and therefore fail to meet the high temperature resistance; fourth, in terms of resistance to 92# gasoline, both hydroxyl-containing silicone resin and hydroxyl-containing acrylic resin meet the requirements, but the hydroxyl-containing polyester resin has poor resistance to 92# gasoline, and the coating exhibits surface wrinkling.

[0141] Again, in terms of the photoaging performance of Examples 1-4 and Comparative Examples 1-2, it was found that the hydroxyl-containing polyester resin had worse performance than the hydroxyl-containing silicone resin and the hydroxyl-containing acrylic resin. At the same time, too much heat stabilizing additive would affect the photoaging performance of the paint film, and the heat stabilizing additives commonly used in the market were not conducive to the photoaging performance of the high-gloss varnish system of the present invention.

[0142] 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. A high-temperature resistant high-gloss varnish coating composition for carbon fiber composite materials, characterized in that: Contains component A and component B; In parts by weight, the component A is composed of 50-80 parts of a hydroxyl resin, 10-35 parts of a first solvent, 0.1-2 parts of a heat stabilizing agent, 0.5-3 parts of an ultraviolet light absorber, 0.1-2 parts of other additives, and 0.5-2 parts of a light stabilizer; the component B is composed of 40-90 parts of an isocyanate curing agent and 10-60 parts of a second solvent; The weight ratio of component A to component B is 1:10-20:1; The hydroxy resin is selected from hydroxyl-containing silicone resins; The heat stabilizing agent is selected from polyhydric hindered phenol antioxidants and / or organic phosphate antioxidants; The heat stabilizing agent is selected from one or more of Irganox 1010, Irganox 1076, RIANOX 1010, RIANOX 1076, RIANOX 1098, IRGAFOS 168, and RIANOX168.

2. The high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The isocyanate curing agent is selected from one or more of aliphatic isocyanate monomers, aliphatic isocyanate polymers, alicyclic isocyanate monomers, alicyclic isocyanate polymers, aromatic isocyanate monomers, aromatic isocyanate polymers, isocyanate hybrids, and isocyanate hybrid polymers.

3. The high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The first solvent and the second solvent are the same or different, and are each 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 high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The other additives are selected from 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 high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The viscosity of the high-temperature resistant high-gloss varnish coating composition at 23° C. is in the range of 100-20,000 mPa·s.

6. The high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The viscosity of the high-temperature resistant high-gloss varnish coating composition at 23° C. is in the range of 100-10000 mPa·s.

7. The high temperature resistant high gloss varnish coating composition according to claim 1, characterized in that: The viscosity of the high-temperature resistant high-gloss varnish coating composition at 23° C. is in the range of 100-5000 mPa·s.

8. A method for preparing a high-temperature resistant high-gloss varnish coating composition for carbon fiber composite materials according to any one of claims 1 to 7, characterized in that: The following steps are included: (1) Adding a hydroxy resin, a heat stabilizing agent, an ultraviolet light absorber, a light stabilizer, and a first solvent into a container A under stirring, and mixing them uniformly to obtain the component A; (2) Adding an isocyanate curing agent and a second solvent to container B under stirring, and mixing them evenly to obtain component B; (3) Component A and component B are mixed in proportion to obtain the high-temperature resistant high-gloss varnish coating composition.

9. A high-temperature resistant high-gloss varnish coating, characterized in that: At least one layer of the high-temperature resistant high-gloss varnish coating composition for carbon fiber composite materials according to any one of claims 1 to 7 is coated on at least one surface of the carbon fiber composite material to obtain a high-temperature resistant high-gloss varnish coating.

10. The high temperature resistant high gloss varnish coating according to claim 9, characterized in that: The coating method is selected from air spraying, airless spraying, online electrostatic spraying or in-mold coating.

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