Composition capable of being used for two-component matte metal color finish paint, repair metal color finish paint containing composition, preparation method and application of repair metal color finish paint

Abstract

The invention discloses a composition capable of being used for two-component matte metallic color finish paint, two-component matte repairing metallic color finish paint containing the composition as well as a preparation method and application of the composition. The composition is prepared from the following components in parts by weight: 10 to 20 parts of high-hydroxyl acrylic resin, 18 to 30 parts of medium-hydroxyl acrylic resin, 10 to 20 parts of matting resin, 5 to 10 parts of coloring pigment paste, 15 to 35 parts of auxiliaries and 10 to 20 parts of solvent, wherein the hydroxyl value of the high-hydroxyl acrylic resin is 130-150 mgKOH / g, the acid value is 5-25 mgKOH / g, the solid content is greater than or equal to 70%, and the viscosity is 2000-5000 mpa.s; the hydroxyl value of the medium-hydroxyl acrylic resin is 90-110 mgKOH / g, the acid value is 5-15 mgKOH / g, the solid content is greater than or equal to 60%, and the viscosity is 1000-4000 mpa.s. The problem that color difference easily occurs after the automobile matte paint film is repaired can be solved.

Description

Technical Field

[0001] The present invention relates to the field of automotive matte repair paint, and more specifically, to a composition that can be used for a two-component matte metallic topcoat, a repair metallic topcoat containing the composition, and a preparation method and application thereof. Background Art

[0002] The repair of metallic topcoat of common car paint requires two spraying processes, namely one repair metallic paint and one two-component clear coat. Although such spraying process is time-consuming and labor-intensive for high-gloss paint film, the construction process and paint are very mature, and there will be no color difference and gloss difference between the overall color of the car and the repaired part, and the effect after repair is basically the same as the original paint film. When the matte paint film adopts the two-layer spraying process, the flash of the repair metallic paint will affect the gloss of the two-component matte varnish, and the refraction of light by the two-component matte varnish will also affect the color display. Therefore, under the superposition of the mutual influence of the repair metallic paint and the matte varnish, the repair construction of the metallic matte paint film becomes more difficult, and color difference and film blooming are prone to occur. The interface boundary marks and gloss inconsistency with the original matte paint, commonly known as "patches", seriously affect the appearance of the car paint.

[0003] The matte paint film on the car body is prone to color difference after repair. This is because the interface boundary marks and glossiness of the sprayed matte repair varnish and the original matte paint are inconsistent, resulting in the paint film blooming. The above phenomenon has always been a major problem in the repair of matte paint films on cars, and the construction operation is cumbersome and difficult to master.

[0004] In view of the above problems, it is particularly important to develop a two-component matte metallic topcoat that has both coloring and glazing functions. Summary of the invention

[0005] Based on the above problems, the purpose of the present invention is to provide a composition that can be used for a two-component matte metallic topcoat, a repair metallic topcoat containing the composition, and a preparation method and application, so as to solve the problem of color difference that easily occurs after the matte paint film of an automobile is repaired.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a composition that can be used for a two-component matte metallic topcoat, comprising the following components in parts by weight:

[0008]

[0009] The high-hydroxy acrylic resin has a hydroxyl value of 130-150 mg KOH / g, an acid value of 5-25 mg KOH / g, a solid content of ≥70%, and a viscosity of 2000-5000 mpa.s;

[0010] The medium hydroxy acrylic resin has a hydroxyl value of 90-110 mg KOH / g, an acid value of 5-15 mg KOH / g, a solid content of ≥60%, and a viscosity of 1000-4000 mpa.s.

[0011] Furthermore, the auxiliary agent contains 5-10 parts of matting powder;

[0012] The matting powder contains inorganic matting powder and organic matting powder, wherein the particle size of the inorganic matting powder ranges from 4-10 μm and 1-3 μm, preferably from 4-6 μm and 1-3 μm, and the particle size of the organic matting powder is 3-7 μm.

[0013] Furthermore, the particle size of the inorganic matting powder in the matting powder ranges from 4 to 5 μm and 1.5 to 2.5 μm, and the particle size of the organic matting powder ranges from 3.5 to 6 μm.

[0014] Furthermore, the auxiliary agent also contains 0.5-3 parts of micro powder wax.

[0015] Furthermore, the particle size of the micropowder wax is 6-14 μm.

[0016] Furthermore, the additive further comprises 5-15 parts of a rheological additive, and the rheological additive is selected from polyethylene wax and / or EVA wax.

[0017] Furthermore, the solvent is one or more of butyl acetate, propylene glycol methyl ether acetate, DBA, IBIB, MAK and EEP.

[0018] Furthermore, the auxiliary agent also contains one or more of the following components:

[0019] 0.5-3 parts of micro powder wax, 3-8 parts of metal effect pigments, 0.5-2 parts of cellulose acetate, 0.5-2 parts of chloroacetic resin, 0.3-1 parts of light stabilizer, 0.3-1 parts of ultraviolet light absorber, 0.2-1 parts of leveling agent, 0.5-1 parts of dispersant and 0.01-0.2 parts of catalyst.

[0020] In another aspect, the present invention provides a two-component matte repair metallic color topcoat, which comprises a main agent prepared from the composition as described above, and a curing agent component.

[0021] Furthermore, the molar ratio of OH in the main agent to NCO in the curing agent is 1:0.9-1.1.

[0022] In another aspect, the present invention provides a method for preparing the above-mentioned two-component matte repair metallic color topcoat, comprising the preparation of a main agent, wherein the preparation of the main agent comprises the following steps:

[0023] Providing a composite matte slurry obtained by mixing part of a solvent, part of an auxiliary agent and a medium-hydroxy acrylic resin;

[0024] Providing a metallic pigment premixed solution obtained by mixing a part of solvent, a part of auxiliary agent and a high-hydroxy acrylic resin;

[0025] After the matting resin and the remaining solvent are mixed, the metal pigment premixed liquid, the composite matting slurry, the remaining auxiliary agents and the coloring pigment paste are added under stirring conditions and mixed evenly to obtain the main agent.

[0026] Furthermore, the preparation of the main agent comprises the following steps:

[0027] Under stirring conditions, cellulose acetate and chloroacetate resin are dissolved in part of the solvent to obtain a solution with a fineness of ≤5 μm; medium hydroxy acrylic resin, dispersant, matting powder, and micro powder wax are added under stirring conditions to disperse to a fineness of ≤20 μm to obtain a composite matting pulp;

[0028] After mixing part of the solvent and the metal effect pigment until there are no particles, add the rheological additive, continue stirring, add the high hydroxyl acrylic resin, and stir until the fineness is ≤25μm to obtain the metal pigment premix;

[0029] After the matting resin and the remaining solvent are mixed, the metal pigment premixed liquid, the composite matting slurry, the catalyst, the ultraviolet light absorber, the light stabilizer, the leveling agent, and the coloring pigment paste are added under stirring conditions and mixed evenly to obtain the main agent.

[0030] In another aspect, the present invention provides a matte repair metallic topcoat coating, which is prepared by mixing a main agent and a curing agent in the two-component matte repair metallic topcoat as described above and applying the mixture to a substrate.

[0031] The beneficial effects of the present invention are as follows:

[0032] According to the metallic color topcoat composition provided by the present invention, by adjusting the ratio or type of high hydroxyl acrylic resin and medium hydroxyl acrylic resin and preferably using a plurality of hydroxyl-containing polymers (including cellulose acetate, chlorovinyl resin, matting resin and organic matting powder), the hydroxyl groups of hydroxyl acrylic resin and hydroxyl-containing polymer react with curing agent to form a paint film with high crosslinking density, so that the matte metallic color topcoat has good hardness, chemical resistance and directional arrangement of metallic pigments. Preferably, a plurality of matting particles of different particle sizes and types and rheological directing agents, cellulose acetate, chlorovinyl resin and functional additives are matched to form more uniform microparticles on the surface of the paint film to evenly diffusely scatter light, and the gloss error range is between 1-5 (60°) under different film thicknesses (error is 5-10 μm). Therefore, the paint film has good construction tolerance and gloss stability. The repair paint film formed by the repair metallic color topcoat provided by the present invention has excellent chemical resistance and weather resistance, outstanding light retention and excellent mechanical properties and hardness. DETAILED DESCRIPTION

[0033] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0034] A specific embodiment of the present invention provides a composition that can be used for a two-component matte metallic topcoat, comprising the following components in parts by weight:

[0035]

[0036] The high-hydroxy acrylic resin has a hydroxyl value of 130-150 mg KOH / g, an acid value of 5-25 mg KOH / g, a solid content of ≥70%, and a viscosity of 2000-5000 mpa.s;

[0037] The medium hydroxy acrylic resin has a hydroxyl value of 90-110 mg KOH / g, an acid value of 5-15 mg KOH / g, a solid content of ≥60%, and a viscosity of 1000-4000 mpa.s.

[0038] The high hydroxyl acrylic resin has a high hydroxyl content and forms a paint film with a high cross-linking density after reacting with a curing agent. The paint film is tough and plump, and has excellent weather resistance, light retention and chemical resistance. Exemplarily, the hydroxyl value of the high hydroxyl acrylic resin is 130-140 mg KOH / g, 140-150 mg KOH / g, 138.6 mg KOH / g, etc. Exemplary addition amounts of high hydroxyl acrylic resins include, but are not limited to, 10-18 parts, 15-18 parts, 15-20 parts, 18-20 parts, 18 parts, etc.

[0039] Exemplarily, the high hydroxyl acrylic resin includes, but is not limited to, Tires 2885 from Allnex and / or Hypomer FS-4470 from Hypomer.

[0040] The medium hydroxy acrylic resin has good wettability and dispersibility for pigments or matting agents, and especially has a higher carrying capacity for matting agents. For example, the hydroxyl value of the medium hydroxy acrylic resin is 90-100 mg KOH / g, 100-110 mg KOH / g, etc.

[0041] Exemplary medium hydroxyl acrylic resins include, but are not limited to, TIRES selected from Allnex TM 2890 and / or Hypomer FS-2860A of Himes. Exemplary addition amounts of the medium hydroxyl acrylic resin include, but are not limited to, 18-25 parts, 25-30 parts, 18-22 parts, 18.9-25 parts, 18.9-22 parts, 22 parts, 18.9 parts, and the like.

[0042] By adjusting the ratio and type of high-hydroxyl acrylic resin and medium-hydroxyl acrylic resin and preferably using a variety of hydroxyl-containing polymers in combination, the hydroxyl groups of the acrylic resin and the hydroxyl-containing polymer react with the curing agent to form a paint film with a high cross-linking density, so that the matte metallic topcoat has better hardness, chemical resistance and directional arrangement of the metallic pigment.

[0043] Furthermore, the auxiliary agent contains 5-10 parts of matting powder.

[0044] In some examples, the matting powder contains inorganic matting powder and organic matting powder, wherein the particle size of the inorganic matting powder ranges from 4-10 μm and 1-3 μm, preferably 4-6 μm and 1-3 μm, and the particle size of the organic matting powder is 3-7 μm.

[0045] That is to say, in this example, the matting powder contains inorganic matting powder (inorganic matting powder with large particle size) with a particle size of 4-10 μm and inorganic matting powder (inorganic matting powder with small particle size) with a particle size of 1-3 μm, and organic matting powder with a particle size of 3-7 μm. The inorganic matting powder with large particle size (such as silica matting powder) has excellent matting efficiency and scratch resistance. The particle size of the exemplary inorganic matting powder with large particle size includes but is not limited to 4-5 μm, 4-6 μm, 5-6 μm, 8-10 μm, etc.; the inorganic matting powder with small particle size (such as silica matting powder) has a delicate feel and is not easy to bloom when applied thinly. The particle size of the exemplary inorganic matting powder with small particle size includes but is not limited to 1.5-2.5 μm, etc.; the organic matting powder is a spherical particle, and its particle size is controlled so that the micro-hemispherical particles evenly distributed on the surface of the paint film form a more effective scattering of light. Because of its high refractive index, it has excellent compatibility with resins, does not affect the transparency of the paint film while matting, does not thicken, and has very little effect on the viscosity and fluidity of the coating. Exemplary organic matting powders include, but are not limited to, 3.5-6 μm.

[0046] In some examples, the mass ratio of the inorganic matting powder with a particle size of 4-10 μm, the inorganic matting powder with a particle size of 1-3 μm, and the organic matting powder with a particle size of 3-7 μm is 1:0.5-2:0.5-2. In this case, the chemical resistance, weather resistance, gloss retention and mechanical properties of the paint film are better. Exemplarily, the mass ratio is 1:0.5-1:0.5-1, 1:1-2:1-2, 1:1:1, etc.

[0047] Exemplarily, the inorganic matting powder is selected from silicon dioxide matting powder. The selection of silicon dioxide matting powder includes but is not limited to TS100 matting powder (particle size is 8-10 μm), OK607 matting powder (particle size is 4-5 μm) and Tosoh E-1011 matting powder (particle size is 1.5-2.5 μm) from Evonik.

[0048] For example, the organic matting powder includes, but is not limited to, 2098PMMA polymer microspheres from Longhai Chemical, M5, M6, etc.

[0049] Further, the additive also contains 0.5-3 parts of micro powder wax. The particle size of the micro powder wax is preferably 6-14 μm. Further exemplary particle sizes of micro powder wax include but are not limited to 9-14 μm, etc. Such wax powder particles will protrude from the surface of the paint film under the action of the rheological additive, and while matting, they will also become contact points for surface friction, thereby protecting the real paint film, thereby reducing the damage to the paint film caused by friction; micro powder wax forms a smooth lubricating layer on the paint film, which can reduce the friction coefficient of the coating and improve the surface smoothness and scratch resistance. Exemplary micro powder wax is a mixed wax of polyethylene and polyamide wax or PTFE modified polyethylene wax, such as one or more of Lubrizol wax powder Lanco 1400SF, Lanco 1588SF, Lanco TF 1778, BASF's LuwaxAF30 and BYK's CERAFLOUR-996 wax powder. Exemplary micro powder wax content includes but is not limited to 0.5-1 parts, 1-3 parts, 1 part, etc.

[0050] Exemplarily, the matting resin includes but is not limited to one or more selected from Hypomer MT-2550K, MT-2550F, and Hypomer MT-2350 of Hymens. Such matting resin has self-matting property, and when used with matting powder, the amount of matting powder added can be reduced to provide a delicate and soft paint film appearance. Exemplary contents of the matting resin include but are not limited to 10-15 parts, 15-20 parts, 15 parts, etc.

[0051] In this technical solution, the composite matting slurry prepared by using matting resin, inorganic matting powder of different particle sizes, organic matting powder and micro-powder wax can reduce the gloss of the paint film under the synergistic matting effect of several matting powders while also having good scratch resistance and wear resistance. Due to the use of matting powders of different particle sizes and types, the matte paint film still has a uniform gloss under different paint film thickness conditions, thereby avoiding the paint film blooming phenomenon caused by different film thicknesses.

[0052] Exemplarily, the additive further comprises 5-15 parts of rheological additives, which are selected from polyethylene wax and / or EVA wax. Such rheological additives may also be referred to as rheological orienting agents. Such rheological additives can provide viscosity stability, and their good thixotropy can effectively prevent the precipitation of metallic pigments, prevent sagging and help the directional arrangement of metallic pigments during the film formation process, and improve the glitter of metallic pigments. Exemplary contents of rheological additives include, but are not limited to, 8-15 parts, 5-8 parts, 8 parts, etc.

[0053] Exemplarily, the rheological additive is a polymer formed by the aggregation of polyethylene wax slurry and EVA wax slurry. It has a good lifting effect on the metal effect particles. In addition, its rheological thickening effect increases the viscosity of the system, effectively preventing the metal effect particles from drifting randomly, thereby helping the metal effect particles to be oriented, reducing cloud-like color difference and spots, and enhancing the metallic feel of the paint film. It also prevents the metal effect pigments in the matte metallic topcoat from precipitating during storage, and does not produce sagging during construction and spraying. It can also effectively prevent the matte particles from micro-precipitating during the drying process, making the paint film gloss more stable.

[0054] Suitable rheological additives include, but are not limited to, one or more selected from CERAFAK 110, Disparlon NS-5501 of BYK, DeuRheo 556S of Hemmings, and 226 silver powder directing agent of Longhai Chemical.

[0055] Exemplarily, the solvent is one or more of butyl acetate, propylene glycol methyl ether acetate, DBA, IBIB, MAK and EEP. In a preferred example, the solvent includes butyl acetate, propylene glycol methyl ether acetate, Eastman's DBA, IBIB, MAK and EEP. The use of solvents with different boiling points and high solvency reduces the viscosity of matte metallic topcoat and is also beneficial to the wet film spreadability of matte metallic topcoat, so that it can form a complete paint film in the case of thin coating, preventing the paint film from blooming and uneven gloss. Because this type of solvent is an environmentally friendly solvent with strong solvency, moderate evaporation rate, and does not contain benzene-based substances, it also greatly reduces the VOC in matte metallic topcoat.

[0056] Furthermore, the auxiliary agent also contains one or more of the following components:

[0057] 0.5-3 parts of micro powder wax, 3-8 parts of metal effect pigments, 0.5-2 parts of cellulose acetate, 0.5-2 parts of chloroacetic resin, 0.3-1 parts of light stabilizer, 0.3-1 parts of ultraviolet light absorber, 0.2-1 parts of leveling agent, 0.5-1 parts of dispersant and 0.01-0.2 parts of catalyst.

[0058] Adding cellulose acetate and chlorovinyl resin to matte metallic topcoat can accelerate the release of solvent from the paint film, greatly shorten the surface drying time of the paint film, and effectively reduce the micro-sedimentation of matting particles. Since cellulose acetate and chlorovinyl resin contain hydroxyl groups, they can react with isocyanate curing agent in the presence of catalyst to form a hardener that does not affect its own hardness but gives the paint film flexibility and enhances wear resistance.

[0059] Exemplary cellulose acetate includes, but is not limited to, CAB, such as CAB-553-0.4, CAB-381-2, CAB-551-0.01, CAB-531-1, etc. from Eastman. Such cellulose acetate has excellent weather resistance, provides outstanding viscosity stability and excellent leveling performance, promotes the orientation performance of metallic pigments, and enhances the glitter of metallic pigments.

[0060] Exemplary vinyl chloride resins are hydroxyl-containing vinyl chloride / vinyl acetate copolymers and terpolymers, such as Wacker's E 22 / 48A, H15 / 45M and one or more of Nissin Chemical's chlorovinyl resins SOLBIN TA3 and SOLBIN A. This type of chlorovinyl resin contains hydroxyl functional groups, which can undergo cross-linking reactions with curing agents to enhance the adhesion, flexibility, hardness and chemical resistance of the coating, as well as very good water resistance.

[0061] By adding metallic effect pigments and coloring pigment paste, the matte repair metallic color topcoat has metallic effect, tinting power and hiding power. There is no need to pay special attention to the construction of this matte repair metallic color topcoat when spraying. It only needs to be applied and dried in the same way as other metal repair topcoats. No additional matte varnish is required. After the paint film is completely dry, it has both the tinting power, metallic feel and sparkle of the metallic color topcoat and the various properties of the matte varnish.

[0062] Exemplary metal effect pigments are aluminum powder pigments and pearlescent pigments. Aluminum powder pigments include, but are not limited to, Toyo aluminum paste, aluminum silver paste from Starlink, aluminum silver paste from Schlenk, etc. Pearlescent pigments include, but are not limited to, one or more of Merck's pearlescent pigments and CQV's pearlescent pigments. Such metal effect pigments provide a strong metallic effect and have excellent weather resistance and coloring ability.

[0063] Exemplary color pigment pastes are commercially available pastes, including but not limited to one or more of Nippon Paint's LACS BASE black, white, blue, purple, and chestnut red. Such pastes are color pigment pastes made by grinding acrylic resin as a grinding carrier, adding a mixed solvent, a dispersant, and inorganic or organic pigments. They are used to adjust the color of matte metallic topcoats, have a narrow particle size distribution, high transparency, good coloring ability and weather resistance, and improve the color and hiding power of the paint film.

[0064] Exemplarily, the light stabilizer is a hindered amine light stabilizer, such as one or more of RIASORB UV-292 and RIASORB UV-123 from Rianlon New Materials and TINUVIN 123 from BASF. The light stabilizer effectively prevents paint defects such as cracking, gloss loss, and chalking, thereby increasing the service life of the coating.

[0065] Exemplarily, the ultraviolet light absorber is a benzotriazole ultraviolet light absorber, such as one or more of RIASORB 384-2 and RIASORB UV-1130 of Lianlong New Materials Company, Tinuvin 384-2 and Tinuvin 1130 of BASF Company. The ultraviolet light absorber has very high thermal stability and light resistance, and is suitable for use in coating surfaces exposed to high temperatures for a long time and in extreme climate environments. Its wide ultraviolet absorption spectrum can effectively protect the paint film.

[0066] Exemplarily, the leveling agent is an organic silicone leveling agent. For example, one or more of BYK's BYK-320, BYK-310 and Evonik's Tego-410, Tego-280. This type of leveling agent can effectively reduce the surface tension of the coating solution, which is beneficial to the atomization of the coating and the wetting and spreading of the substrate. Even a very thin paint film can be quickly leveled; when the paint film is completely dry, the organic silicone leveling agent migrates to the surface of the paint film, increasing the smoothness and scratch resistance of the paint film.

[0067] Exemplarily, the dispersant is a copolymer solution having a pigment affinity group, such as BYK-103, BYK-P104S of BYK or Borchi Gen0755, Borchi Gen1051 of OMG. This type of dispersant has good wettability and dispersibility for organic and inorganic matting powders, can improve the fluidity of matting slurry and good anti-floating performance; because of its excellent compatibility, it can achieve a very good transparency effect.

[0068] Exemplarily, the catalyst is a commercially available metal salt catalyst, such as one or more of Borchi Kat 22, Borchi Kat 0243 and Air Chemical T-12 from OMG. Compared with other catalysts, this type of catalyst has a longer activation period at the same addition amount without affecting the drying time, and improves the crosslinking density and hardness of the paint film.

[0069] In this technical solution, high hydroxyl acrylic resin, medium hydroxyl acrylic resin and matting resin are selected as the main resin, and matting particles of various sizes and types, rheological directing agents, cellulose acetate, chlorovinyl resin and functional additives are matched to form more uniform microparticles on the surface of the paint film to evenly diffuse and scatter light, so that the gloss error range is between 1-5 (60°) under different film thicknesses (error is 5-10μm). Therefore, the paint film has good construction tolerance and gloss stability.

[0070] On the other hand, a specific embodiment of the present invention provides a two-component matte repair metallic topcoat, which comprises a main agent prepared from the composition as described above, and a curing agent component.

[0071] Exemplarily, the curing agent component includes 40-70 parts of HDI polyurethane curing agent, 30-60 parts of solvent, and 0.5-1 part of dehydrating agent.

[0072] The HDI polyurethane curing agent is a commercially available aliphatic polyisocyanate, such as BASF's HI-100, Asahi Kasei's Duranate TPA 100, Covestro's Desmodur N3390 or Wanhua Chemical's One or more of HT-100. This type of curing agent is a low-viscosity and highly reactive isocyanate, which forms a paint film with hydroxyl functional groups and has excellent chemical resistance and weather resistance, outstanding gloss retention and excellent mechanical properties and hardness.

[0073] The dehydrating agent is a low-viscosity single-functional group isocyanate or ester compound, such as one or more of Additive TI and Additive OF from OMG. This type of dehydrating agent has high reactivity and can eliminate a very small amount of water in the system, thereby solving the problem caused by the intervention of water in the air or the intervention of water in the solvent during the preparation of the paint, and can also solve the adverse phenomena caused by the intervention of water in the humid construction environment.

[0074] An exemplary solvent is selected from butyl acetate.

[0075] Exemplarily, the molar ratio of OH in the main agent to NCO in the curing agent is 1:0.9-1.1.

[0076] Furthermore, the two-component matte metallic repair topcoat is a car paint repair matte metallic topcoat.

[0077] According to another specific embodiment of the present invention, a method for preparing a two-component matte repair metallic color topcoat is provided, comprising the preparation of a main agent, wherein the preparation of the main agent comprises the following steps:

[0078] Providing a composite matte slurry obtained by mixing part of a solvent, part of an auxiliary agent and a medium-hydroxy acrylic resin;

[0079] Providing a metallic pigment premixed solution obtained by mixing a part of solvent, a part of auxiliary agent and a high-hydroxy acrylic resin;

[0080] After the matting resin and the remaining solvent are mixed, the metal pigment premixed liquid, the composite matting slurry, the remaining auxiliary agents and the coloring pigment paste are added under stirring conditions and mixed evenly to obtain the main agent.

[0081] Furthermore, the preparation of the main agent comprises the following steps:

[0082] Under stirring conditions (preferably at a stirring speed of 400-600 r / min), cellulose acetate and chloroacetate resin are dissolved in part of the solvent to obtain a solution with a fineness of ≤5 μm; medium-hydroxy acrylic resin, dispersant, matting powder, and micro-powder wax are added under stirring conditions (preferably at a stirring speed of 400-600 r / min) to disperse to a fineness of ≤20 μm to obtain a composite matting pulp;

[0083] After mixing part of the solvent and the metal effect pigment (preferably at a stirring speed of 400-600 r / min) until there are no particles, add the rheological additive, continue stirring (preferably at a stirring speed of 1500-3000 r / min), add the high hydroxyl acrylic resin, and stir until the fineness is ≤25 μm to obtain a metal pigment premix;

[0084] After mixing the matting resin and the remaining solvent, add the metallic pigment premix, composite matting slurry, catalyst, ultraviolet light absorber, light stabilizer, leveling agent, and coloring pigment paste under stirring (preferably at a stirring speed of 400-600 r / min) and mix well to obtain the main agent.

[0085] In the preparation process of the above composite matte slurry, the addition speed of the chlorovinyl resin cannot be too fast, in order to make it evenly distributed in the solvent to facilitate rapid dissolution. If it is added too quickly, the powder will agglomerate and be difficult to dissolve.

[0086] The composite matte slurry prepared as above has the characteristics of good fluidity, good redispersibility, stable matte property, easy addition and the like.

[0087] The metallic pigment premix prepared as above has the characteristics of good directional arrangement, strong metallic feel, not easy to aggregate and coarse, and easy to add.

[0088] Furthermore, in the above preparation process, after adding coloring pigment paste and the like and mixing evenly, the steps of adjusting color, adjusting viscosity, adjusting gloss and the like are also included.

[0089] In some examples, the preparation of the curing agent component includes the following steps:

[0090] Add solvent and dehydrating agent to a clean, water-free reactor, start stirring at 400-600r / min for 5-10 minutes, then slowly add HDI polyurethane curing agent and continue stirring for 10-20 minutes, then adjust to the appropriate viscosity with an appropriate amount of solvent, and use it as a curing agent component after passing the inspection.

[0091] The curing agent has good storage stability, does not contain benzene solvents and has little odor. After forming a paint film with the hydroxyl functional group in the main agent, it has excellent chemical resistance, weather resistance, outstanding gloss retention, and excellent mechanical properties and hardness.

[0092] According to another specific embodiment of the present invention, a matte repair metallic topcoat coating is provided, which is prepared by mixing a substance comprising a main agent and a curing agent component of the two-component matte repair metallic topcoat as described above and applying the mixture to a substrate.

[0093] Exemplarily, the dry film thickness of the coating is 20±5 μm.

[0094] The coating film has a gloss of 20±2 (60°); a hardness of HB-H (Mitsubishi pencil); and a coating film appearance of fine and smooth without blooming.

[0095] In actual operation, after the main agent and the curing agent components are mixed, a diluent may be further added according to actual viscosity requirements, and the mixture is diluted with the diluent before being applied to the substrate.

[0096] Exemplarily, the main agent, the curing agent component and the diluent in the two-component matte repair metallic topcoat are mixed in a mass ratio of 3:1:0.3-1 and then applied to the substrate.

[0097] Exemplarily, the diluent is a mixed solvent, and the mixing ratio is butyl acetate: propylene glycol methyl ether acetate: S-100# solvent in a mass ratio of 1:1:1.

[0098] The substrate is where the car body needs to be repaired with matte metallic finish.

[0099] Exemplarily, the method for forming the coating specifically includes the following steps:

[0100] After mixing the main agent and curing agent components, add diluent to dilute to the required viscosity according to actual needs to obtain the coating liquid;

[0101] The coating liquid is sprayed on the substrate and baked at 70-90° C. for 30-40 minutes to obtain the coating.

[0102] In some more specific examples, the method of forming the coating specifically includes the following steps:

[0103] After mixing the main agent and curing agent components, dilute with diluent to a viscosity of 24-28S (FORD#4CUP / 25℃);

[0104] Use an IWATA W-101 spray gun with a caliber of 1.0mm to spray. Adjust the spray gun to fully open the spray fan, the spit volume is 2 circles, the compressed air pressure is 0.2-0.3Mpa, the distance between the spray gun nozzle and the substrate is kept between 180-220mm, and then use two cross-spraying methods to evenly spray the matte metallic topcoat where it is needed to be repaired;

[0105] The sprayed wet film is allowed to stand for 8-15 minutes and then baked at 70-90°C for 30-40 minutes to obtain a coating.

[0106] The dry film thickness of the coating is 20±5 μm; the paint film gloss is 20±2 (60°); the hardness is HB-H (Mitsubishi pencil); the coating film appearance is fine and smooth without blooming.

[0107] The technical solution of the present invention is described below in conjunction with some specific embodiments:

[0108] Example 1

[0109] The two-component matte repair metallic topcoat comprises a main agent and a curing agent component, wherein the composition of the main agent is shown in Table 1 below.

[0110] The preparation of the repair metallic color topcoat comprises the following steps:

[0111] Preparation of main agent:

[0112] Step a. Preparation of composite matte pulp: according to the raw material ratio, add a mixed solvent into a clean mixing tank, slowly add cellulose acetate and chloroacetic resin powders under stirring at a speed of 400-600r / min to dissolve until completely transparent and particle-free, and then detect the fineness ≤5μm to determine complete dissolution. Continue to stir at a speed of 400-600r / min, sequentially add medium hydroxy acrylic resin, dispersant, silica matting powder, organic matting powder, and micro powder wax, stir for 5-10 minutes until the powder is completely immersed in the resin solution, and then disperse at a stirring speed of 1500-3000r / min for 20-30 minutes, detect the fineness ≤20μm, and prepare composite matte pulp.

[0113] Step b. Preparing a metallic pigment premix: Add a mixed solvent and metallic effect pigments to a clean mixing tank according to the raw material ratio. Start stirring and stir at a speed of 400-600 r / min for 5-10 minutes until the mixture is completely uniform and free of particles, then slowly add a rheological additive and continue stirring for 5-10 minutes. Then add a high hydroxyl acrylic resin and stir for 5-10 minutes. Detect the fineness to be ≤25 μm to prepare a metallic pigment premix.

[0114] Step c. preparing a matte metallic topcoat main agent A: according to the raw material ratio, add a matte resin and a solvent into a clean mixing tank, start stirring, and add a metallic pigment premix, a composite matte slurry, a catalyst, an ultraviolet light absorber, a light stabilizer, a leveling agent, and a coloring pigment slurry at a speed of 400-600 r / min and stir for 10-20 minutes, then use an appropriate amount of the coloring pigment slurry to adjust to a suitable color, an appropriate amount of the solvent to adjust to a suitable viscosity, and an appropriate amount of the composite matte slurry to adjust to a suitable gloss. After passing the inspection, it is used as the matte metallic topcoat main agent A.

[0115] Preparation of curing agent component:

[0116] Preparation of curing agent component B: according to the raw material ratio, add solvent (59.2 parts of butyl acetate) and dehydrating agent (0.3 parts of Additive TI and 0.5 parts of Additive OF) into a clean and water-free reactor, start stirring and stir at a speed of 400-600r / min for 5-10 minutes, and then slowly add HDI polyurethane curing agent (40 parts HI-100) continue stirring for 10-20 minutes, then adjust to a suitable viscosity with an appropriate amount of butyl acetate, and use it as curing agent B component after passing the inspection.

[0117] Among them, the mass ratio of the main agent A and the curing agent B components of the matte metallic topcoat is 3:1.

[0118] application:

[0119] The repair metal color topcoat is used to repair the car body, and the specific steps are as follows:

[0120] After mixing the main agent and curing agent components, dilute with an appropriate amount of diluent (the mass ratio of main agent, curing agent and diluent is 3:1:0.3-1) to a viscosity of 24-28S (FORD#4CUP / 25℃);

[0121] Use an IWATA W-101 spray gun with a caliber of 1.0mm to spray, adjust the spray gun to fully open the spray fan, the spit volume is 2 circles, and the compressed air pressure is 0.2-0.3Mpa. Keep the distance between the spray gun nozzle and the substrate between 180-220mm, and then spray evenly in two cross-spraying methods on the matte metallic topcoat that needs to be repaired;

[0122] After the sprayed wet film is left to stand for 8-15 minutes, it is baked at 70-90℃ for 30-40 minutes to obtain a dry film.

[0123] The performance results of the coating films are shown in Table 1 below.

[0124] Table 1

[0125]

[0126]

[0127] Example 2-Example 3 and Comparative Example 1-Comparative Example 6

[0128] The two-component matte repair metallic topcoat of Examples 2-3 and Comparative Examples 1-6 comprises a main agent and a curing agent component, wherein the composition of the main agent is shown in Table 1. Other components and application methods are as in Example 1. The performance results of the obtained coating film are shown in Table 1.

[0129] Embodiment 4-6

[0130] The curing agent component formula in the formula of Example 4 to Example 6 is shown in Table 2 below, and the formula of the main agent is shown in Example 1. The preparation method and application method are the same as in Example 1. The results obtained are shown in Table 2 below.

[0131] Table 2

[0132]

[0133]

[0134] Embodiment 7-9

[0135] The main agent formula in the formula of Example 7 to Example 9 is shown in Table 3 below, and the formula of the curing agent is shown in Example 1. The preparation method and application method thereof are the same as in Example 1. The obtained results are shown in Table 3 below.

[0136] Table 3

[0137]

[0138]

[0139] Comparative Example 7-Comparative Example 10

[0140] The formulations of Comparative Examples 7 to 10 are shown in Table 3 above. The preparation methods and application methods thereof are the same as those of Example 1. The results obtained are shown in Table 3 above.

[0141] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A composition for a two-component matte metallic topcoat, characterized in that: By weight, it contains the following components: The high-hydroxy acrylic resin has a hydroxyl value of 130-150 mg KOH / g, an acid value of 5-25 mg KOH / g, a solid content of ≥70%, and a viscosity of 2000-5000 mpa.s; The medium hydroxy acrylic resin has a hydroxyl value of 90-110 mg KOH / g, an acid value of 5-15 mg KOH / g, a solid content of ≥60%, and a viscosity of 1000-4000 mpa.s.

2. The composition according to claim 1, characterized in that The auxiliary agent contains 5-10 parts of matting powder; The matting powder contains inorganic matting powder and organic matting powder, wherein the particle size of the inorganic matting powder ranges from 4-10 μm and 1-3 μm, preferably from 4-6 μm and 1-3 μm, and the particle size of the organic matting powder is 3-7 μm.

3. The composition according to claim 1, characterized in that The auxiliary agent further comprises 5-15 parts of a rheological auxiliary agent, and the rheological auxiliary agent is selected from polyethylene wax and / or EVA wax.

4. The composition according to claim 1, characterized in that The solvent is one or more of butyl acetate, propylene glycol methyl ether acetate, DBA, IBIB, MAK and EEP.

5. The composition according to any one of claims 1 to 4, characterized in that The auxiliary agent also includes one or more of the following components: 0.5-3 parts of micro powder wax, 3-8 parts of metal effect pigments, 0.5-2 parts of cellulose acetate, 0.5-2 parts of chloroacetic resin, 0.3-1 parts of light stabilizer, 0.3-1 parts of ultraviolet light absorber, 0.2-1 parts of leveling agent, 0.5-1 parts of dispersant and 0.01-0.2 parts of catalyst.

6. A two-component matte repair metallic finish, characterized in that: The invention comprises a main agent prepared from the composition according to any one of claims 1 to 5, and a curing agent component.

7. The two-component matte repair metallic color topcoat according to claim 6, characterized in that: The molar ratio of OH in the main agent to NCO in the curing agent is 1:0.9-1.

1.

8. The method for preparing a two-component matte repair metallic color topcoat according to claim 6 or 7, characterized in that: The preparation of the main agent includes the following steps: Providing a composite matte slurry obtained by mixing part of a solvent, part of an auxiliary agent and a medium-hydroxy acrylic resin; Providing a metallic pigment premixed solution obtained by mixing a part of solvent, a part of auxiliary agent and a high-hydroxy acrylic resin; After the matting resin and the remaining solvent are mixed, the metal pigment premixed liquid, the composite matting slurry, the remaining auxiliary agents and the coloring pigment paste are added under stirring conditions and mixed evenly to obtain the main agent.

9. The method for preparing a two-component matte repair metallic color topcoat according to claim 8, characterized in that: The preparation of the main agent comprises the following steps: Under stirring conditions, cellulose acetate and chloroacetate resin are dissolved in part of the solvent to obtain a solution with a fineness of ≤5 μm; medium hydroxy acrylic resin, dispersant, matting powder, and micro powder wax are added under stirring conditions to disperse to a fineness of ≤20 μm to obtain a composite matting pulp; After mixing part of the solvent and the metal effect pigment until there are no particles, add the rheological additive, continue stirring, add the high hydroxyl acrylic resin, and stir until the fineness is ≤25μm to obtain the metal pigment premix; After the matting resin and the remaining solvent are mixed, the metal pigment premixed liquid, the composite matting slurry, the catalyst, the ultraviolet light absorber, the light stabilizer, the leveling agent, and the coloring pigment paste are added under stirring conditions and mixed evenly to obtain the main agent.

10. A matte repair metallic topcoat coating, characterized in that: The main agent in the two-component matte repair metallic topcoat as described in any one of claims 6-7 or the main agent and the curing agent component in the two-component matte repair metallic topcoat prepared by the preparation method according to any one of claims 8-9 are mixed and applied to the substrate.

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