Two-component varnish composition, spraying method and color register finish paint

Abstract

The invention provides a two-component varnish composition, a spraying method and a color register finishing coat, and belongs to the technical field of vehicle body spraying, the two-component varnish composition comprises a first main agent and a first curing agent, the weight ratio of the first main agent to the first curing agent is 3.5: 1-4: 1; wherein the first main agent is prepared from the following components in parts by weight: 30 to 39 parts of acrylic resin, 12 to 19 parts of amino resin, 15 to 22 parts of anti-sagging resin, 0.6 to 1.1 parts of an auxiliary agent and 14 to 37 parts of a first solvent; the first curing agent comprises a polyisocyanate curing agent. According to the present invention, by optimizing the ratio of the components in the two-component varnish composition, the adhesion between the paint layers is improved when the two-component varnish composition is used for spraying the vehicle body, such that the polishing on the vehicle body is reduced after the paint spraying is completed, or even the polishing is not performed, the process flow beat is reduced, and the batch production requirement of the vehicle is met.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle body spraying, and in particular to a two-component varnish composition, a spraying method and a color-matching topcoat. Background Art

[0002] With the rapid development of the new energy vehicle industry, personalized consumer demand has become a major trend in the automotive market, especially for vehicle appearance. A single color scheme can no longer meet the needs of consumers.

[0003] At present, the color spraying process is often used to spray the vehicle body to achieve a multi-color vehicle body. However, in the related technology, during the spraying process, the adhesion between the paint layers is low, which requires multiple polishing and finishing of the vehicle body, resulting in a long process cycle and unable to meet the mass production needs of vehicles. Summary of the invention

[0004] In view of this, the present application proposes a two-component varnish composition, a spraying method and a color topcoat to enhance the interlayer adhesion, thereby reducing or even eliminating the need to polish the vehicle body during spraying, saving process time and meeting the mass production needs of vehicles.

[0005] The first aspect of the embodiment of the present application provides a two-component varnish composition, comprising: a first main agent and a first curing agent, wherein the weight ratio of the first main agent to the first curing agent is 3.5:1 to 4:1;

[0006] Wherein, the first main agent comprises, by weight: 30 to 39 parts of acrylic resin, 12 to 19 parts of amino resin, 15 to 22 parts of anti-sagging resin, 0.6 to 1.1 parts of auxiliary agent and 14 to 37 parts of first solvent;

[0007] The first curing agent includes a polyisocyanate curing agent.

[0008] Optionally, the acrylic resin includes one or a mixture of multiple types in any proportion of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate and lauryl methacrylate.

[0009] Optionally, the amino resin includes one of methyl etherified melamine resin and methyl etherified hexamethylol melamine resin or a mixture of multiple thereof in any proportion.

[0010] Optionally, the anti-sagging resin includes one of modified acrylic resin and polyamide wax slurry or a mixture of multiple thereof in any proportion.

[0011] Optionally, the auxiliary agent includes one of a leveling agent, a defoaming agent and a drying agent, or a plurality of the above-mentioned agents mixed in any proportion;

[0012] Among them, the leveling agent includes one of modified silicone, epoxy-modified polyacrylate and modified organic polysiloxane polyisocyanate or a combination of multiple thereof in any proportion; the defoaming agent includes one of polyamide hydrophobic particle polymer and propylene glycol methyl ether acetate or a combination of multiple thereof in any proportion; the drying agent includes one of dibutyltin dilaurate and p-toluenesulfonic acid amino salt solution or a combination of multiple thereof in any proportion.

[0013] Optionally, the first solvent includes one of ethyl acetate, solvent oil, ethylene glycol butyl ether acetate, diethylene glycol butyl ether, dimethyl carbonate, isopropyl alcohol and diethyl carbonate, or a mixture of multiple thereof in any proportion.

[0014] A second aspect of an embodiment of the present application provides a spraying method, the spraying method comprising:

[0015] Step S1, spraying a water-based intermediate coating on the electrophoresis treated vehicle body to form a first water-based intermediate coating layer, and then spraying a first color paint on the color matching area of ​​the vehicle body to form a first color paint layer;

[0016] Step S2, performing a first flash-drying treatment on the vehicle body sprayed with the first color paint;

[0017] Step S3, after the first flash-drying treatment is completed, spraying a first two-component varnish composition on the vehicle body, and after the spraying is completed, performing a first drying treatment on the vehicle body to obtain a first varnish layer;

[0018] Step S4, after the first drying process is completed, the defective points on the vehicle body are polished, and the vehicle body is cleaned with a second solvent to complete the paint surface production of the color matching area;

[0019] Step S5, masking the color-matching area, and after masking, spraying the water-based intermediate coating and the second color paint on the main color area in sequence to form a second water-based intermediate coating layer and a second color paint layer, and then performing a second flash-drying process;

[0020] Step S6, after the second flash-drying treatment is completed, spraying a second two-component varnish composition on the main color area to form a second varnish layer;

[0021] Step S7, after the spraying is completed, the main color area is subjected to a second drying process, and after the drying is completed, the shielding is removed to obtain a two-color topcoat vehicle body;

[0022] Wherein, the first two-component varnish composition is the two-component varnish composition described in the first aspect above; the first color paint and the second color paint have different colors; and the second solvent is alcohol or isopropyl alcohol.

[0023] Optionally, the second two-component varnish composition comprises: a second main agent and a second curing agent, wherein the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1;

[0024] Wherein, the second main agent comprises, by weight, 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of the first solvent.

[0025] Optionally, in step S1, the thickness of the water-based mid-coat sprayed is 9 to 15 μm;

[0026] In the step S2, the first color paint is sprayed to a thickness of 10 to 15 μm;

[0027] In the step S3, the first two-component varnish composition is sprayed to a thickness of 35 to 45 μm;

[0028] In the step S5, the water-based intermediate coating is sprayed to a thickness of 9 to 15 μm, and the second color paint is sprayed to a thickness of 10 to 15 μm;

[0029] In the step S6, the second two-component varnish composition is sprayed to a thickness of 45-60 μm.

[0030] Optionally, the first flash-drying treatment and the second flash-drying treatment include: flash-drying the vehicle body at 75 to 85° C. for 4 to 6 minutes;

[0031] The first drying process and the second drying process include: baking at 130-150° C. for 20-30 minutes.

[0032] The third aspect of the embodiment of the present application provides a color matching topcoat, including a color matching area topcoat and a main color area topcoat; wherein,

[0033] The color-matching area topcoat comprises: a first water-based intermediate coating layer, a first color paint layer and a first clear varnish layer which are sequentially stacked on the surface of the vehicle body;

[0034] The main color area topcoat comprises: a second water-based intermediate coating layer, a second color paint layer and a second clear varnish layer which are sequentially stacked on the surface of the vehicle body;

[0035] The topcoat at the junction of the overprinting area and the main color area includes: a first water-based intermediate coating layer, a first color paint layer, a first clear coat layer, a second water-based intermediate coating layer, a second color paint layer and a second clear coat layer which are sequentially stacked on the surface of the vehicle body; wherein

[0036] The first color paint and the second color paint have different colors;

[0037] The first aqueous mid-coat layer and the second aqueous mid-coat layer are both formed by spraying an aqueous mid-coat;

[0038] The first varnish layer is formed by spraying the two-component varnish composition according to any one of claims 1 to 5;

[0039] The second varnish layer is formed by spraying a second two-component varnish composition, and the second two-component varnish composition comprises: a second main agent and a second curing agent, and the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1; counted by weight, the second main agent comprises: 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of first solvent.

[0040] The present application has the following advantages over the prior art:

[0041] (1) The present application optimizes the weight ratio of the first main agent to the first curing agent and reduces the amount of the first curing agent, so that when the vehicle body is sprayed, the acrylic resin in the first main agent can leave more unreacted active groups to combine with the active groups in the second two-component varnish composition sprayed later to form chemical bonds and enhance interlayer adhesion. (2) The present application reduces the weight of the amino resin in the first main agent, thereby reducing the cross-linking density and leaving more active sites, so that further chemical reactions occur during the second drying treatment of the vehicle body, thereby improving interlayer adhesion. (3) The present application reduces the weight of the auxiliary agent in the first main agent, improves the surface roughness of the paint film, and is conducive to the formation of physical forces between layers in the form of hydrogen bonds or mechanical riveting, further enhancing interlayer adhesion.

[0042] Therefore, the first two-component varnish composition provided by the present application is used to spray the vehicle body, which ensures the interlayer adhesion requirements. Only the defective points on the vehicle body need to be polished, and even polishing is not required after spraying the second two-component varnish composition, which saves process beats and meets the mass production needs of vehicles. In addition, the present application adopts a five-coat and two-bake topcoat process to improve the overall feel, flatness, brightness, fullness, etc. of the paint surface, greatly improving the appearance of the paint surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0044] Figure 1 A flow chart showing the steps of the spraying method according to an embodiment of the present application;

[0045] Figure 2 This is a schematic diagram of a car body with topcoat in a color-matching area shown in an embodiment of the present application;

[0046] Figure 3 This is a schematic diagram of a vehicle body with topcoat in the main color area shown in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned purpose, features and advantages of the present application more obvious and easy to understand, the preferred embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and replacements to the present invention without departing from the purpose and spirit of the present invention. The materials, reagents, etc. used in the following examples, if not otherwise specified, can all be obtained from commercial sources.

[0048] In the related art, the B1B2 spraying process is often used to achieve the painting of two-color vehicles. The B1B2 spraying process is: electrophoretic grinding - wiping - spraying intermediate paint (color matching) - spraying color paint (color matching) - flash drying - spraying varnish (color matching) - drying - fine grinding - masking - wiping - spraying intermediate paint (primary color) - spraying color paint (primary color) - flash drying - spraying varnish (primary color) - drying - lower masking - fine repair - submission. In this process, due to the low adhesion between the paint layers, manual fine grinding is required after each drying, resulting in a long time for the entire spraying process, and the beat cannot meet the mass production demand of more than 30 vehicles per hour. In addition, the use of manual fine grinding also has the disadvantages of low operating efficiency, high grinding quality requirements, increased labor costs, and easy generation of particles.

[0049] In view of this, the first aspect of the embodiment of the present application proposes a two-component varnish composition to improve the layer adhesion, so that when spraying the vehicle body, the grinding is reduced or even eliminated, the process beat is saved, and the mass production requirements of the vehicle are met. The two-component varnish composition includes: a first main agent and a first curing agent, and the weight ratio of the first main agent to the first curing agent is 3.5:1 to 4:1;

[0050] Wherein, by weight, the first main agent includes: 30 to 39 parts of acrylic resin, 12 to 19 parts of amino resin, 15 to 22 parts of anti-sagging resin, 0.6 to 1.1 parts of auxiliary agent and 14 to 37 parts of first solvent.

[0051] In an embodiment of the present application, the two-component varnish composition includes a first main agent and a first curing agent, wherein the first main agent includes 30 to 39 parts of acrylic resin, 12 to 19 parts of amino resin, 15 to 22 parts of anti-sagging resin, 0.6 to 1.1 parts of auxiliary agent and 14 to 37 parts of first solvent; the first curing agent includes a polyisocyanate curing agent.

[0052] Before the two-component varnish composition is used, the first main agent and the first curing agent are packaged and stored separately. When in use, the first main agent and the first curing agent are mixed in proportion, and the two undergo addition polymerization to form a paint film. In the embodiment of the present application, the weight ratio of the first main agent to the first curing agent is 3.5:1 to 4:1. In this way, the amount of the first curing agent is reduced, so that after the addition polymerization reaction, the acrylic resin in the first main agent can leave a large number of unreacted active groups, which can be combined with the active groups in the subsequently sprayed two-component varnish to form chemical bonds, thereby enhancing interlayer adhesion and reducing grinding operations.

[0053] In one example, the polyisocyanate curing agent may include aliphatic polyisocyanates and alicyclic polyisocyanates. Such curing agents do not contain aromatic groups, will not produce benzene ring conjugated quinone chromophores, will not produce yellowing, and are beneficial to the color stability of the paint film.

[0054] The aliphatic polyisocyanate includes one of hexamethylene diisocyanate and 2,2,4-trimethylhexane diisocyanate or a plurality of them mixed in any proportion; the alicyclic isocyanate includes one of dicyclohexylmethylene diisocyanate and isophorone diisocyanate or a plurality of them mixed in any proportion.

[0055] In addition, the embodiment of the present application also reduces the weight percentage of the amino resin in the first main agent, and adopts 12 to 19 parts of amino resin, thereby reducing the cross-linking density when the addition polymerization reaction occurs, leaving more active sites, so that further chemical reactions can occur when the car body is subsequently dried, thereby improving the interlayer adhesion.

[0056] The auxiliary agent includes one or more of leveling agent, defoamer and drying agent in any proportion. The leveling agent is used to reduce the surface tension between the two-component varnish composition and the vehicle body, so that the two-component varnish composition and the vehicle body have good wettability and do not form a surface tension gradient between the substances that cause shrinkage cavities; on the other hand, it is used to adjust the evaporation rate of the first solvent, reduce viscosity, improve the fluidity of the two-component varnish composition, prolong the leveling time, and make the formed paint film more glossy; the defoamer has a spontaneous defoaming effect, can prevent microbubbles, and can effectively improve the paint film surface from bubbling; the drying agent can shorten the coating curing film forming time, increase the coating film strength and water resistance, and is also beneficial to the wetting and dispersion of the pigment, and improves the viscoelasticity of the coating.

[0057] In an embodiment of the present application, the first main agent includes 0.6 to 1.1 parts of the above-mentioned auxiliary agent. In this way, reducing the amount of auxiliary agent, especially reducing the amount of leveling agent, can improve the surface roughness of the formed paint film, which is conducive to the formation of physical forces between layers in the form of hydrogen bonds or mechanical riveting, thereby further enhancing adhesion.

[0058] Therefore, the embodiment of the present application optimizes the proportion of each component in the two-component varnish composition, so that when the two-component varnish composition is used to spray the vehicle body, the adhesion between the paint layers is improved, thereby reducing the polishing of the vehicle body after the painting is completed, or even eliminating the polishing, reducing the process flow rhythm, and meeting the mass production needs of vehicles.

[0059] In an optional embodiment, the acrylic resin includes one or a mixture of multiple thereof in any proportion among methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate and lauryl methacrylate.

[0060] In the embodiments of the present application, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate and lauryl methacrylate are all thermosetting resins. The above thermosetting resins have good gloss and color retention, water resistance and chemical resistance, so that the formed paint film has excellent fullness, gloss, hardness, solvent resistance, weather resistance, and does not change color or turn yellow when baked at high temperature.

[0061] In an optional embodiment, the amino resin includes one of methyl etherified melamine resin and methyl etherified hexamethylol melamine resin or a mixture of multiple thereof in any proportion.

[0062] In the embodiments of the present application, methyl etherified melamine resin and / or methyl etherified hexamethylol melamine resin are used so that the formed paint film has excellent gloss.

[0063] In an optional embodiment, the anti-sagging resin includes one of modified acrylic resin and polyamide wax slurry or a mixture of multiple thereof in any proportion.

[0064] In the embodiments of the present application, the anti-sagging resin includes modified acrylic resin and / or polyamide wax slurry, which significantly improves the anti-sagging performance, high gloss and dust-proof effect of the paint film.

[0065] In an optional embodiment, the auxiliary agent includes one or a plurality of the following selected from the group consisting of a leveling agent, a defoaming agent and a drying agent in any proportion;

[0066] The leveling agent includes one or a plurality of polyisocyanates of modified silicone, epoxy-modified polyacrylate and modified organic polysiloxane in any proportion; the defoaming agent includes polyamide hydrophobic particle polymer; and the drying agent includes dibutyltin dilaurate.

[0067] In an optional embodiment, the first solvent includes one or a mixture of multiple solvents selected from the group consisting of ethyl acetate, solvent oil, ethylene glycol butyl ether acetate, diethylene glycol butyl ether, dimethyl carbonate, isopropyl alcohol and diethyl carbonate in any proportion.

[0068] In the embodiments of the present application, the use of the above-mentioned solvent is not only green and environmentally friendly, but also can significantly improve the deep surface quality and provide a good product construction environment.

[0069] Based on the common knowledge in this field, the above-mentioned preferred conditions can be combined with each other to obtain a specific implementation method.

[0070] Based on the same inventive concept, the second aspect of the embodiment of the present application proposes a spraying method, which adopts a five-coat and two-bake topcoat process, combined with the two-component varnish composition described in the first aspect above, so that during the entire spraying process, grinding is reduced or even eliminated, saving process time and meeting the mass production requirements of vehicles. The spraying method can refer to Figure 1 , Figure 1 A flow chart of the steps of a spraying method described in an embodiment of the present application is shown. Figure 1 As shown, the spraying method comprises the following steps:

[0071] Step S1, spraying a water-based intermediate coating on the electrophoresis-treated vehicle body color-coating area to form a first water-based intermediate coating layer, and then spraying a first color paint on the vehicle body color-coating area to form a first color paint layer;

[0072] Step S2, performing a first flash-drying treatment on the vehicle body sprayed with the first color paint;

[0073] Step S3, after the first flash-drying treatment is completed, spraying a first two-component varnish composition on the color-coated area of ​​the vehicle body, and after the spraying is completed, performing a first drying treatment on the vehicle body to obtain a first varnish layer;

[0074] Step S4, after the first drying process is completed, the defective points on the vehicle body are polished, and the vehicle body is cleaned with a second solvent to complete the paint surface production of the color matching area;

[0075] Step S5, masking the color-matching area, and after masking, spraying the water-based intermediate coating and the second color paint on the main color area in sequence to form a second water-based intermediate coating layer and a second color paint layer, and then performing a second flash-drying process;

[0076] Step S6, after the second flash-drying treatment is completed, spraying a second two-component varnish composition on the main color area to form a second varnish layer;

[0077] Step S7, after the spraying is completed, the main color area is subjected to a second drying process, and after the drying is completed, the shielding is removed to obtain a two-color topcoat vehicle body;

[0078] Wherein, the first two-component varnish composition is the two-component varnish composition described in the first aspect above; the first color paint and the second color paint have different colors; and the second solvent is alcohol or isopropyl alcohol.

[0079] In the embodiment of the present application, a five-coat and two-bake topcoat process is used to spray two colors on the vehicle body. First, the body is electrophoretically treated to obtain an electrophoretic body, and then a water-based mid-coat is sprayed on the electrophoretic body. After the spraying is completed, the color matching area of ​​the body is determined, and the first color paint is sprayed in the color matching area. The first color paint can be a color paint of any color.

[0080] After spraying the first color paint, the vehicle body is subjected to a first flash drying treatment. Specifically, the vehicle is moved into a flash drying oven for leveling and dehydration.

[0081] After the first flash-drying treatment, the vehicle body is sprayed with a first two-component varnish composition, which is the two-component varnish composition described in the first aspect, and after the spraying is completed, the vehicle body is subjected to a first drying treatment. Specifically, the vehicle is moved into a topcoat drying oven for leveling and curing.

[0082] Next, the defective points on the car body are confirmed and polished. After polishing, the car body is cleaned with a second solvent, such as alcohol or isopropyl alcohol. In this way, not only the dust and foreign matter on the car body can be wiped clean, but also the car body can be kept dry. In this way, the topcoat preparation of the color matching area is completed, and the following is obtained: Figure 2 Topcoat of the color-coded area shown.

[0083] Next, the color-matching area is masked, and after the masking is completed, the water-based intermediate coating and the second color paint are sprayed on the body in sequence. The second color paint is different in color from the first color paint. After the spraying is completed, a second flash drying process is performed. Specifically, the vehicle is moved into a flash drying oven for leveling and dehydration.

[0084] After the second flash-drying treatment is completed, a second two-component varnish composition is sprayed on the vehicle body, and the second two-component varnish composition is different from the first two-component varnish composition.

[0085] After the spraying is completed, the car body is subjected to a second drying treatment. Specifically, the vehicle is moved into a topcoat drying oven for leveling, curing and drying to complete the topcoat preparation of the main color area. Figure 3 Finally, remove the masking of the overprinted color area to complete the vehicle topcoat preparation.

[0086] In the embodiment of the present application, in step S3, when the vehicle body is sprayed with the first two-component varnish composition, since the weight ratio of the first main agent to the first curing agent in the first two-component varnish composition is 3.5:1 to 4:1, the amount of the first curing agent is reduced, so that after the addition polymerization reaction of the first main agent and the first curing agent, the acrylic resin in the first main agent can leave a large number of unreacted active groups, and these active groups can combine with the active groups of the subsequently sprayed two-component varnish composition, that is, the second two-component varnish composition sprayed in step S6, to form chemical bonds, thereby enhancing the interlayer adhesion and reducing the polishing operation.

[0087] Secondly, since the weight proportion of the amino resin in the first main agent is relatively small, 12 to 19 parts, the crosslinking density is reduced during the addition polymerization reaction, leaving more active sites, so that in step S7, when the car body is subjected to the second drying treatment, further chemical reactions can occur to improve the interlayer adhesion.

[0088] In addition, the embodiment of the present application adopts a first two-component varnish composition to reduce the amount of additives, especially the amount of leveling agent, thereby improving the surface roughness of the formed paint film, which is conducive to the formation of physical forces between layers in the form of hydrogen bonds or mechanical riveting, thereby further enhancing adhesion.

[0089] Therefore, in the two-color spraying process, the embodiment of the present application combines the first two-component varnish composition to ensure the interlayer adhesion requirements. After the first drying treatment, the defects caused by the paint mist pollution in the middle coating process are reduced. There is no need to polish the entire car body, and only the defective points of the car body need to be polished; and, after the second drying treatment, due to the enhanced interlayer adhesion, there is no need to polish the car body, thereby achieving polish-free operation, solving the problems of long polishing operation and high polishing quality requirements in the traditional two-color car process, greatly improving efficiency and reducing costs.

[0090] In addition, the embodiment of the present application also adopts a five-coat and two-bake topcoat process to greatly improve the overall feel, smoothness, brightness, and fullness of the paint surface.

[0091] In an optional embodiment, the second two-component varnish composition comprises: a second main agent and a second curing agent, wherein the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1;

[0092] Wherein, the second main agent comprises, by weight, 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of the first solvent.

[0093] The acrylic resin includes one or a plurality of them mixed in any proportion among methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate and lauryl methacrylate.

[0094] The amino resin includes one of methyl etherified melamine resin and methyl etherified hexamethylol melamine resin or a mixture of multiple types in any proportion.

[0095] The anti-sagging resin includes one of modified acrylic resin and polyamide wax slurry or a mixture of multiple thereof in any proportion.

[0096] The auxiliary agent includes one or more of a leveling agent, a defoaming agent and a drying agent in any proportion. The leveling agent includes one or more of modified silicone, epoxy-modified polyacrylate and modified polyisocyanate of organic polysiloxane in any proportion; the defoaming agent includes one or more of polyamide hydrophobic particle polymer and propylene glycol methyl ether acetate in any proportion; the drying agent includes one or more of dibutyltin dilaurate and p-toluenesulfonic acid amino salt solution in any proportion.

[0097] The first solvent includes one of ethyl acetate, solvent oil, ethylene glycol butyl ether acetate, diethylene glycol butyl ether, dimethyl carbonate, isopropyl alcohol and diethyl carbonate, or a mixture of multiple solvents in any proportion.

[0098] In an embodiment of the present application, in step S6, a second two-component varnish composition is used to spray the vehicle body, so that the acrylic resin in the second main agent can leave more active groups to combine with the active groups left in the previous step S3 to form chemical bonds, thereby greatly enhancing the interlayer adhesion.

[0099] In an optional embodiment, in the step S1, the thickness of the water-based mid-coat sprayed is 9 to 15 μm;

[0100] In the step S2, the first color paint is sprayed to a thickness of 10 to 15 μm;

[0101] In the step S3, the first two-component varnish composition is sprayed to a thickness of 35 to 45 μm;

[0102] In the step S5, the water-based intermediate coating is sprayed to a thickness of 9 to 15 μm, and the second color paint is sprayed to a thickness of 10 to 15 μm;

[0103] In the step S6, the second two-component varnish composition is sprayed to a thickness of 45-60 μm.

[0104] In an embodiment of the present application, the thickness of the water-based mid-coat is set to 9-15 μm, the thickness of the first color paint is set to 10-15 μm, the thickness of the first two-component clear coat composition is set to 35-45 μm, the thickness of the second color paint is set to 10-15 μm, and the thickness of the second two-component clear coat composition is set to 45-60 μm, so as to achieve the best effect of orange peel protection for the car body under the condition of minimum cost.

[0105] In an optional embodiment, the first flash drying treatment and the second flash drying treatment include: flash drying the vehicle body at 75 to 85° C. for 4 to 6 minutes;

[0106] The first drying process and the second drying process include: baking at 130-150° C. for 20-30 minutes.

[0107] In the embodiment of the present application, the first flash-drying treatment and the second flash-drying treatment can make the sprayed water-based intermediate coating and color paint obtain excellent leveling and dehydration, and improve the spraying quality; through the first drying treatment and the second drying treatment, the sprayed two-component varnish (the first two-component varnish composition, the second two-component varnish composition) can obtain excellent leveling and curing, and further improve the spraying quality. Thus, the present application adopts a five-coating and two-baking topcoat process, combined with the first two-component varnish composition and the second two-component varnish composition, while greatly improving the overall sense, flatness, brightness, and fullness of the paint surface, ensuring the interlayer adhesion requirements, after the first drying treatment, reducing the defects caused by the paint mist pollution in the intermediate coating process, without the need to polish the entire body, only the defective points of the body need to be polished; and, after the second drying treatment, due to the enhancement of the interlayer adhesion, there is no need to polish the body, and the polishing-free is realized, which solves the problem that the polishing operation of the traditional two-color car process is time-consuming and the polishing quality requirements are high, greatly improving efficiency and reducing costs.

[0108] Based on the same inventive concept, the third aspect of the embodiment of the present application provides a color matching topcoat, including a color matching area topcoat and a main color area topcoat; Figure 2 Schematic diagram of a painted vehicle body in a color-matching area shown in an embodiment of the present application; Figure 2 As shown, the color-matching area topcoat comprises: a first water-based intermediate coating layer, a first color paint layer and a first clear varnish layer sequentially stacked on the surface of the vehicle body; Figure 3 This is a schematic diagram of a main color area topcoat vehicle body shown in an embodiment of the present application, such as Figure 3 As shown, the main color area topcoat includes: a second water-based mid-coat layer, a second color paint layer and a second clear varnish layer which are sequentially stacked on the surface of the vehicle body.

[0109] The topcoat at the junction of the overprinting area and the main color area includes: a first water-based intermediate coating layer, a first color paint layer, a first clear coat layer, a second water-based intermediate coating layer, a second color paint layer and a second clear coat layer which are sequentially stacked on the surface of the vehicle body.

[0110] The first color paint and the second color paint have different colors;

[0111] The first aqueous mid-coat layer and the second aqueous mid-coat layer are both formed by spraying an aqueous mid-coat;

[0112] The first varnish layer is formed by spraying the two-component varnish composition according to any one of claims 1 to 5;

[0113] The second varnish layer is formed by spraying a second two-component varnish composition, and the second two-component varnish composition comprises: a second main agent and a second curing agent, and the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1; counted by weight, the second main agent comprises: 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of first solvent.

[0114] Below, in order to enable those skilled in the art to better understand the present application, the two-component varnish composition and the spraying method thereof provided by the present application are described below through a number of specific embodiments.

[0115] Example 1

[0116] This embodiment 1 provides a first two-component varnish composition, including a first main agent and a first curing agent, the weight ratio of the first main agent to the first curing agent is 4:1, wherein the first curing agent is hexamethylene diisocyanate, and the composition of the first main agent is as follows:

[0117]

[0118] This embodiment 1 also provides a second two-component varnish composition, including a second main agent and a second curing agent, wherein the weight ratio of the second main agent to the second curing agent is 3:1, wherein the second curing agent is hexamethylene diisocyanate, and the composition of the second main agent is as follows:

[0119]

[0120] A five-coat and two-bake topcoat spraying method comprises the following steps:

[0121] Step S1, spraying a water-based intermediate coating on the color-matching area of ​​the vehicle body treated by electrophoresis, with a film thickness of 12 μm, and then spraying a silver paint on the color-matching area of ​​the vehicle body and the roof, with a film thickness of 13 μm;

[0122] Step S2, moving the vehicle into a flash drying oven for leveling and dehydration, the flash drying condition is 80° C. for 5.5 min;

[0123] Step S3, after flash drying, spray the first two-component varnish composition on the color-matching area of ​​the vehicle body, with a film thickness of 40 μm. After spraying, move the vehicle into a topcoat baking oven for leveling and curing, and the drying condition is baking at 140° C. for 20 minutes;

[0124] Step S4, after drying, polishing the defective points on the car body and wiping the car body clean with alcohol;

[0125] Step S5, masking the roof, after masking is completed, spraying water-based intermediate coating and black paint on the main color area of ​​the vehicle body in sequence, wherein the water-based intermediate coating film thickness is 12μm, and the black paint film thickness is 13μm. Then, the vehicle is moved into a flash drying oven for leveling and dehydration, and the flash drying condition is 80℃ flash drying for 5.5min;

[0126] Step S6, after flash drying is completed, spraying the second two-component varnish composition on the main color area of ​​the vehicle body;

[0127] Step S7, after spraying is completed, the vehicle is moved into a topcoat drying oven for leveling and curing. The drying condition is baking at 140°C for 20 minutes. After drying, the shielding is removed to obtain a two-color topcoat vehicle body.

[0128] Comparative Example 1

[0129] This comparative example 1 provides a two-component varnish composition, including a main agent and a curing agent, the weight ratio of the main agent to the curing agent is 3:1, wherein the curing agent is hexamethylene diisocyanate, and the composition of the main agent is as follows:

[0130]

[0131] This comparative example also provides a second two-component varnish composition, which is consistent with Example 1.

[0132] A five-coat and two-bake topcoat spraying method includes the same method as embodiment 1.

[0133] Next, the performance board was manufactured and tested according to the conditions of Example 1 and Comparative Example 1, and the results are shown in Table 1 below:

[0134] Table 1. Performance test results of Example 1 and Comparative Example 1

[0135]

[0136]

[0137] As shown in Table 1 above, Example 1 adopts the first two-component varnish composition, which can significantly improve its appearance data such as DOI and orange peel, as well as physical and chemical properties such as adhesion, impact resistance, and moisture and heat resistance, while ensuring the construction performance, which is higher than that of Comparative Example 1.

[0138] Each embodiment in this specification focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other.

[0139] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0140] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0141] The present application has been introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A two-component varnish composition, characterized in that: include: A first main agent and a first curing agent, wherein the weight ratio of the first main agent to the first curing agent is 3.5:1 to 4:1; Wherein, the first main agent comprises, by weight: 30 to 39 parts of acrylic resin, 12 to 19 parts of amino resin, 15 to 22 parts of anti-sagging resin, 0.6 to 1.1 parts of auxiliary agent and 14 to 37 parts of first solvent; The first curing agent includes a polyisocyanate curing agent.

2. A two-component varnish composition according to claim 1, characterized in that: The acrylic resin includes one or a mixture of any proportion of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, hexyl (meth)acrylate and lauryl methacrylate; The amino resin includes one of methyl etherified melamine resin and methyl etherified hexamethylol melamine resin or a mixture of two or more of them in any proportion.

3. A two-component varnish composition according to claim 1, characterized in that: The anti-sagging resin includes one of modified acrylic resin and polyamide wax slurry or a mixture of multiple types in any proportion.

4. A two-component varnish composition according to claim 1, characterized in that: The auxiliary agent includes one or a mixture of multiple agents selected from the group consisting of a leveling agent, a defoaming agent and a drying agent in any proportion; Among them, the leveling agent includes one of modified silicone, epoxy-modified polyacrylate and modified organic polysiloxane polyisocyanate or a combination of multiple thereof in any proportion; the defoaming agent includes one of polyamide hydrophobic particle polymer and propylene glycol methyl ether acetate or a combination of multiple thereof in any proportion; the drying agent includes one of dibutyltin dilaurate and p-toluenesulfonic acid amino salt solution or a combination of multiple thereof in any proportion.

5. A two-component varnish composition according to claim 1, characterized in that: The first solvent includes one of ethyl acetate, solvent oil, ethylene glycol butyl ether acetate, diethylene glycol butyl ether, dimethyl carbonate, isopropyl alcohol and diethyl carbonate, or a mixture of multiple thereof in any proportion.

6. A spraying method, characterized in that: The spraying method comprises: Step S1, spraying a water-based intermediate coating on the color-coated area of ​​the vehicle body treated by electrophoresis to form a first water-based intermediate coating layer, and then spraying a first color paint on the color-coated area of ​​the vehicle body to form a first color paint layer; Step S2, performing a first flash-drying treatment on the vehicle body sprayed with the first color paint; Step S3, after the first flash-drying treatment is completed, spraying a first two-component varnish composition on the color-coated area of ​​the vehicle body, and after the spraying is completed, performing a first drying treatment on the vehicle body to obtain a first varnish layer; Step S4, after the first drying process is completed, the defective points on the vehicle body are polished, and the vehicle body is cleaned with a second solvent to complete the paint surface production of the color matching area; Step S5, masking the color-matching area, and after masking, spraying the water-based intermediate coating and the second color paint on the main color area in sequence to form a second water-based intermediate coating layer and a second color paint layer, and then performing a second flash-drying process; Step S6, after the second flash-drying treatment is completed, spraying a second two-component varnish composition on the main color area to form a second varnish layer; Step S7, after the spraying is completed, the main color area is subjected to a second drying process, and after the drying is completed, the shielding is removed to obtain a two-color topcoat vehicle body; Wherein, the first two-component varnish composition is the two-component varnish composition according to any one of claims 1 to 5; the first color paint and the second color paint have different colors; and the second solvent is alcohol or isopropyl alcohol.

7. A spraying method according to claim 6, characterized in that: The second two-component varnish composition comprises: a second main agent and a second curing agent, wherein the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1; Wherein, the second main agent comprises, by weight, 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of the first solvent.

8. A spraying method according to claim 6, characterized in that: In the step S1, the thickness of the water-based intermediate coating sprayed is 9 to 15 μm; In the step S2, the first color paint is sprayed to a thickness of 10 to 15 μm; In the step S3, the first two-component varnish composition is sprayed to a thickness of 35 to 45 μm; In the step S5, the water-based intermediate coating is sprayed to a thickness of 9 to 15 μm, and the second color paint is sprayed to a thickness of 10 to 15 μm; In the step S6, the second two-component varnish composition is sprayed to a thickness of 45-60 μm.

9. A spraying method according to claim 6, characterized in that: The first flash drying treatment and the second flash drying treatment include: flash drying the vehicle body at 75 to 85° C. for 4 to 6 minutes; The first drying process and the second drying process include: baking at 130-150° C. for 20-30 minutes.

10. A color topcoat, characterized in that: It includes topcoat for the overlay area and topcoat for the main color area; among which, The color-matching area topcoat comprises: a first water-based intermediate coating layer, a first color paint layer and a first clear varnish layer which are sequentially stacked on the surface of the vehicle body; The main color area topcoat comprises: a second water-based intermediate coating layer, a second color paint layer and a second clear varnish layer which are sequentially stacked on the surface of the vehicle body; The topcoat at the junction of the overprinting area and the main color area includes: a first water-based intermediate coating layer, a first color paint layer, a first clear coat layer, a second water-based intermediate coating layer, a second color paint layer and a second clear coat layer which are sequentially stacked on the surface of the vehicle body; wherein The first color paint and the second color paint have different colors; The first aqueous mid-coat layer and the second aqueous mid-coat layer are both formed by spraying an aqueous mid-coat; The first varnish layer is formed by spraying the two-component varnish composition according to any one of claims 1 to 5; The second varnish layer is formed by spraying a second two-component varnish composition, and the second two-component varnish composition comprises: a second main agent and a second curing agent, and the weight ratio of the second main agent to the second curing agent is 3:1 to 3.5:1; counted by weight, the second main agent comprises: 40 to 50 parts of acrylic resin, 20 to 25 parts of amino resin, 20 to 25 parts of anti-sagging resin, 1 to 1.4 parts of auxiliary agent and 10 to 30 parts of first solvent.

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