Low temperature matte refinish paint and dry film particle defect online repair method

Abstract

The application discloses a low-temperature matte repair paint and a dry film particle defect online repair method, and belongs to the technical field of coatings. The low-temperature matte repair paint comprises an A component and a B component, the A component comprises the following components in parts by weight: 50-60 parts of a hydroxyl acrylic acid resin, 2-6 parts of a matte powder, 2-10 parts of an amino resin, 2-10 parts of a pigment, 15-30 parts of a solvent A and 5-10 parts of an additive; the B component comprises the following components in parts by weight: 40-50 parts of an isocyanate and 50-60 parts of a solvent B; the paint film formed by the low-temperature matte repair paint has the advantages of low gloss, good interlayer adhesion, high hiding power and good scratch resistance; the dry film particle defect online repair method provided by the application can efficiently process the particle defects of the dry film formed by the existing matte paint by using the repair paint, the comprehensive coating consumption is low, VOC emission is effectively reduced, and the method is more environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a low-temperature matte repair paint and an online repair method for dry film particle defects. Background Technology

[0002] High-gloss metallic paint has always been the preferred choice for customers, but with changing demands for vehicle personalization and aesthetic preferences, customers are beginning to favor matte paint. However, compared to regular paint, matte paint mainly consists of black paste and matting powder. The main component of matting powder is fumed silica, which has a large number of silanol bonds on its surface. These bonds can form hydrogen bonds with the substrate or on their own. In liquid systems, these bonds easily form a uniform three-dimensional network structure (hydrogen bonds), which "supports" pigments or other fillers, preventing them from settling or clumping. However, this three-dimensional network structure (hydrogen bonds) can be disrupted by external forces (pipeline shear force, electric field force, etc.). Prolonged pipeline circulation can cause pigments and matting powder to settle, forming particle deposits. Particle defects account for about 80% of all defects in matte paint, which is the main reason affecting the straight-line performance of matte paint vehicles. At the same time, the surface gloss of matte paint is low. Once high gloss wax is applied, it will cause obvious differences in local gloss. Therefore, the particle defects of the dry film of matte paint cannot be repaired with high gloss wax. It can only be re-sprayed with matte paint, resulting in a lot of material and energy cost losses. Moreover, the delivery cycle is unstable, which can easily cause missing parts in the next process and make it impossible to achieve the goal of stable mass production.

[0003] Therefore, there is an urgent need to develop a low-temperature matte repair paint to meet the current automotive industry's performance requirements for repair paints. Summary of the Invention

[0004] In view of the deficiencies of the existing technology, the purpose of this invention is to provide a low-temperature matte repair paint and an online repair method for dry film particle defects.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a low-temperature matte repair paint, comprising component A and component B. Component A comprises the following components in parts by weight: 50-60 parts of hydroxyl acrylic resin, 2-6 parts of matte powder, 2-10 parts of amino resin, 2-10 parts of pigment, 15-30 parts of solvent A, and 4-10 parts of additives.

[0007] Component B comprises the following components in parts by weight: 40-50 parts isocyanate and 50-60 parts solvent B;

[0008] Solvent A and solvent B may be the same or different organic solvents.

[0009] This invention optimizes and adjusts the components and dosage of the repair paint, enabling it to form a film at low temperature and dry quickly without a catalyst. The resulting paint film has advantages such as low gloss, good interlayer adhesion, high hiding power, and good wear resistance. Therefore, the repair paint provided by this invention is suitable for repairing particle defects in matte dry films.

[0010] The inventors discovered that when components A and B are mixed and sprayed, the isocyanate in component B can react with the active groups (such as hydroxyl, carboxyl, and amino groups) in component A to form crosslinks, which greatly improves the adhesion of the repair paint.

[0011] In a preferred embodiment of the present invention, the organic solvent includes at least one of butyl acetate, ethyl acetate, 120# solvent oil, acetone, cyclohexanone, ethylene glycol butyl ether, xylene, and toluene.

[0012] In a preferred embodiment of the present invention, the additives include at least one of wetting agents, anti-settling agents, and resistance additives.

[0013] As a preferred embodiment of the present invention, the low-temperature matte repair paint includes the following additives in parts by weight: 1-5 parts wetting agent, 1-5 parts anti-settling agent, and 1-5 parts resistivity additive.

[0014] In a preferred embodiment of the present invention, component A further includes the following components in parts by weight: 2-10 parts of polypropylene carbonate. During their research, the inventors unexpectedly discovered that the molecular chain of polypropylene carbonate contains highly polar ester groups, as well as terminal hydroxyl and terminal carboxyl groups. During the curing process, the molecular chains of polypropylene carbonate become entangled in the system, which not only significantly improves the adhesion of the repair paint but also improves the matte finish and abrasion resistance of the repair paint to a certain extent.

[0015] In a preferred embodiment of the present invention, the weight ratio of component B to component A is (0.2-0.6):1.

[0016] In a preferred embodiment of the present invention, the low-temperature matte repair paint further includes a diluent, wherein the mass ratio of the diluent to component A is (0.3-1):1, and the diluent includes at least one of butyl acetate, xylene, and toluene.

[0017] In a preferred embodiment of the present invention, the additives include at least one of wetting agents, anti-settling agents, and resistance additives.

[0018] In a preferred embodiment of the present invention, the low-temperature matte repair paint further includes a diluent, wherein the mass ratio of the diluent to component A is (0.3-1):1, and the diluent includes at least one of butyl acetate, xylene, and toluene.

[0019] In a preferred embodiment of the present invention, component A comprises the following components in parts by weight: 50-55 parts hydroxyl acrylic resin, 3-4 parts matte powder, 6-8 parts amino resin, 3-5 parts polypropylene carbonate, 3-5 parts pigment, 20-22 parts solvent A, and 6-8 parts additives. When the formulation of component A is within the above range, the matte repair paint exhibits better adhesion and abrasion resistance.

[0020] Secondly, the present invention provides an online repair method for dry film particle defects, comprising the following steps:

[0021] S1. Inspect the matte paint dry film for particle defects;

[0022] S2. Attach sandpaper to the grinding head of the electric grinder and use the electric grinder to rotate the sandpaper on the grinding head to grind the particle defects detected in step S1, so as to remove the particle protrusions and form a grinding defect area on the dry film surface.

[0023] S3. Take the low-temperature matte repair paint as described in the first aspect, mix component A, component B and thinner, apply it to the sanding defect area formed in step S2, and the repair work can be completed after drying.

[0024] In a preferred embodiment of the present invention, in step S2, the diameter of the grinding head of the electric polishing pen is 1-5mm, the grinding head speed is 4000-9000rpm, and the polishing time for each particle defect is 1-5s.

[0025] In a preferred embodiment of the present invention, in step S2, the size of the sand grains on the sandpaper is 1000-3000 mesh.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention optimizes and adjusts the components and dosage of the repair paint, enabling it to form a film at low temperature and dry quickly without a catalyst. The resulting paint film has advantages such as low gloss, good interlayer adhesion, high hiding power, and good scratch resistance. Therefore, the repair paint provided by this invention is suitable for repairing particle defects in matte dry films.

[0028] The online repair method for dry film particle defects provided by this invention can efficiently handle particle defects in dry films formed by existing matte paints, solving the industry problem that existing matte paint dry films cannot be sanded or waxed for repair; it significantly improves the overall straight-line rate and avoids material and energy losses caused by batch rework; the method of this invention has a lower overall paint consumption, effectively reducing VOC emissions and making it more environmentally friendly. Detailed Implementation

[0029] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0030] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0031] The raw material source information for each embodiment and comparative example is shown in Table 1 below.

[0032] Table 1

[0033]

[0034] Example 1

[0035] This embodiment provides a low-temperature matte repair paint, the preparation method of which is as follows:

[0036] (1) Weigh the following parts by weight of component A: 55 parts of hydroxyl acrylic resin, 2 parts of wetting agent, 4 parts of matting powder, 11 parts of butyl acetate, 11 parts of xylene, 3 parts of polyamide anti-settling wax paste, 6 parts of amino resin, 5 parts of black pigment, and 2 parts of resistance additive. Mix the weighed raw materials and grind them to a fineness of no more than 1.5 μm to obtain component A.

[0037] (2) Weigh the following parts by weight of component B raw materials: 45 parts of polyisocyanate and 55 parts of butyl acetate. Mix the polyisocyanate and butyl acetate evenly to obtain component B.

[0038] (3) Weigh the following parts by weight of component C raw materials: 50 parts of butyl acetate and 50 parts of xylene. Mix butyl acetate and xylene evenly to obtain component C.

[0039] This embodiment also provides an online repair method for dry film particle defects, including the following steps:

[0040] S1. Inspect the matte paint dry film for particle defects;

[0041] S2. Attach sandpaper to the grinding head of the electric polishing pen. The grinding head of the electric polishing pen has a diameter of 3mm and the abrasive grain size on the sandpaper is 2000 mesh. Use the electric polishing pen to drive the sandpaper on the grinding head to rotate and polish the particle defects detected in step S1. Control the grinding head speed at 7000rpm and polish each particle defect for 1s to remove particle protrusions and form a polishing defect area on the dry film surface.

[0042] S3. Mix component A, component B and thinner in a weight ratio of A:B:thinner = 1:0.4:0.5 to obtain a well-mixed repair paint. Use a watercolor brush with a 3mm tip to apply the well-mixed repair paint to the sanding defect area formed in step S2 three times. After drying, the repair work is complete.

[0043] Example 2

[0044] This embodiment provides a method for online repair of low-temperature matte repair paint and dry film particle defects. The difference between this embodiment and Embodiment 1 is that the raw material of component A in this embodiment is composed of the following parts by weight: 50 parts of hydroxyl acrylic resin, 2 parts of wetting agent, 4 parts of matte powder, 11 parts of butyl acetate, 11 parts of xylene, 3 parts of polyamide anti-settling wax paste, 6 parts of amino resin, 5 parts of polypropylene carbonate, 5 parts of black pigment, and 2 parts of resistance additive.

[0045] Example 3

[0046] This embodiment provides a method for online repair of low-temperature matte repair paint and dry film particle defects. The difference between this embodiment and Embodiment 1 is that the raw material of component A in this embodiment is composed of the following parts by weight: 52 parts of hydroxyl acrylic resin, 2 parts of wetting agent, 4 parts of matte powder, 11 parts of butyl acetate, 11 parts of xylene, 3 parts of polyamide anti-settling wax paste, 6 parts of amino resin, 3 parts of polypropylene carbonate, 5 parts of black pigment, and 2 parts of resistance additive.

[0047] Example 4

[0048] This embodiment provides a method for online repair of low-temperature matte repair paint and dry film particle defects. The difference between this embodiment and Embodiment 1 is that the raw material of component A in this embodiment is composed of the following parts by weight: 53 parts of hydroxyl acrylic resin, 2 parts of wetting agent, 4 parts of matte powder, 11 parts of butyl acetate, 11 parts of xylene, 3 parts of polyamide anti-settling wax paste, 6 parts of amino resin, 2 parts of polypropylene carbonate, 5 parts of black pigment, and 2 parts of resistance additive.

[0049] Example 5

[0050] This embodiment provides a method for online repair of low-temperature matte repair paint and dry film particle defects. The difference between this embodiment and Embodiment 1 is that the raw material of component A in this embodiment is composed of the following parts by weight: 47 parts of hydroxyl acrylic resin, 2 parts of wetting agent, 4 parts of matte powder, 11 parts of butyl acetate, 11 parts of xylene, 3 parts of polyamide anti-settling wax paste, 6 parts of amino resin, 8 parts of polypropylene carbonate, 5 parts of black pigment, and 2 parts of resistance additive.

[0051] Example 6

[0052] This embodiment provides a low-temperature matte repair paint, the preparation method of which is as follows:

[0053] (1) Weigh the following raw materials in parts by weight: 55 parts hydroxy acrylic resin, 1.5 parts wetting agent, 4 parts matting powder, 10 parts butyl acetate, 10 parts xylene, 4 parts polyamide anti-settling wax paste, 8 parts amino resin, 3 parts polypropylene carbonate, 3 parts black pigment, and 1.5 parts resistance additive. Mix and grind the weighed components until the fineness is no greater than 1.5 μm to obtain component A.

[0054] (2) Weigh the following raw materials in parts by weight: 50 parts polyisocyanate and 50 parts butyl acetate. Mix the polyisocyanate and butyl acetate evenly to obtain component B.

[0055] (3) Weigh the following raw materials in parts by weight: 50 parts of butyl acetate and 50 parts of xylene. Mix the butyl acetate and xylene evenly to obtain component C.

[0056] This embodiment also provides an online repair method for dry film particle defects, including the following steps:

[0057] S1. Inspect the matte paint dry film for particle defects;

[0058] S2. Attach sandpaper to the grinding head of the electric polishing pen. The grinding head of the electric polishing pen has a diameter of 3mm and the abrasive grain size on the sandpaper is 2000 mesh. Use the electric polishing pen to drive the sandpaper on the grinding head to rotate and polish the particle defects detected in step S1. Control the grinding head speed at 8000rpm and polish each particle defect for 1s to remove particle protrusions and form a polishing defect area on the dry film surface.

[0059] S3. Mix component A, component B and diluent in a weight ratio of 4:1:1, apply the mixture to the polishing defect area formed in step S2, and the repair work is completed after drying.

[0060] Example 7

[0061] This embodiment provides a low-temperature matte repair paint, the preparation method of which is as follows:

[0062] (1) Weigh the following raw materials in parts by weight: 60 parts of hydroxyl acrylic resin, 0.5 parts of wetting agent, 2 parts of matting powder, 15 parts of butyl acetate, 15 parts of xylene, 3 parts of polyamide anti-settling wax paste, 2 parts of amino resin, 2 parts of polypropylene carbonate, 2 parts of black pigment, and 0.5 parts of resistance additive. Mix the weighed components and grind them until the fineness is no greater than 1.5 μm to obtain component A.

[0063] (2) Weigh the following raw materials in parts by weight: 50 parts polyisocyanate and 50 parts butyl acetate. Mix the polyisocyanate and butyl acetate evenly to obtain component B.

[0064] (3) Weigh the following raw materials in parts by weight: 50 parts of butyl acetate and 50 parts of xylene. Mix the butyl acetate and xylene evenly to obtain component C.

[0065] This embodiment also provides an online repair method for dry film particle defects, including the following steps:

[0066] S1. Inspect the matte paint dry film for particle defects;

[0067] S2. Attach sandpaper to the grinding head of the electric polishing pen. The grinding head of the electric polishing pen has a diameter of 3mm and the abrasive grain size on the sandpaper is 2000 mesh. Use the electric polishing pen to drive the sandpaper on the grinding head to rotate and polish the particle defects detected in step S1. Control the grinding head speed at 9000rpm and polish each particle defect for 1s to remove particle protrusions and form a polishing defect area on the dry film surface.

[0068] S3. Mix component A, component B and diluent in a weight ratio of 4:1:1, apply the mixture to the polishing defect area formed in step S2, and the repair work is completed after drying.

[0069] Example 8

[0070] This embodiment provides a low-temperature matte repair paint, the preparation method of which is as follows:

[0071] (1) Weigh the following raw materials in parts by weight: 45 parts hydroxy acrylic resin, 3 parts wetting agent, 2 parts matting powder, 10 parts butyl acetate, 10 parts xylene, 5 parts polyamide anti-settling wax paste, 10 parts amino resin, 10 parts polypropylene carbonate, 2 parts black pigment, and 3 parts resistance additive. Mix the weighed components and grind them to a fineness of no more than 1.5 μm to obtain component A.

[0072] (2) Weigh the following raw materials in parts by weight: 40 parts of polyisocyanate and 60 parts of butyl acetate. Mix the polyisocyanate and butyl acetate evenly to obtain component B.

[0073] (3) Weigh the following raw materials in parts by weight: 50 parts of butyl acetate and 50 parts of xylene. Mix the butyl acetate and xylene evenly to obtain component C.

[0074] This embodiment also provides an online repair method for dry film particle defects, including the following steps:

[0075] S1. Inspect the matte paint dry film for particle defects;

[0076] S2. Attach sandpaper to the grinding head of the electric polishing pen. The grinding head of the electric polishing pen has a diameter of 3mm and the abrasive grain size on the sandpaper is 2000 mesh. Use the electric polishing pen to drive the sandpaper on the grinding head to rotate and polish the particle defects detected in step S1. Control the grinding head speed at 4500rpm. The polishing time required for each particle defect is 2.5s to remove particle protrusions and form a polishing defect area on the dry film surface.

[0077] S3. Mix component A, component B and diluent in a weight ratio of 4:1:1, apply the mixture to the polishing defect area formed in step S2, and the repair work is completed after drying.

[0078] To verify the performance of the low-temperature matte repair paint described in this invention, the repair paints prepared in each embodiment were filmed according to the following method: the repair paint was sprayed onto the substrate with a thickness of 30 μm, and dried at 80°C for 20 min to obtain a paint film; then the following performance tests were performed, with the specific steps as follows:

[0079] (1) Gloss: The gloss of the paint film was measured using a BYK gloss meter. The standard range of gloss is 20-25.

[0080] (2) Adhesion: The adhesion of the paint film was measured using an A1189 Cross Hatch Cutter (2mm). The adhesion level requirement is ≤1.

[0081] (3) Abrasion resistance: The initial average gloss B1 (60°) of the test panel was measured using a BYK gloss meter along the length of the test panel (i.e., the direction of brushing) (three measurements were taken in the same area, and the average value was taken). Then, an A1193 AATCCC rockmeter color fastness tester (ATLAS CM-5) was used with a normal pressure of 9N and a contact head of 6.6cm. 2 The linear motion speed was 60 times / min, the stroke was 100mm, and 3M self-adhesive 2400 grit sandpaper was used for 15 reciprocating strokes on the mirror surface of the test panel. After the test, the test panel was placed in a 70℃ oven for 2 hours to allow for recovery. After the recovery period, the final average gloss B3 (60°) of the test panel mirror surface was measured using a BYK gloss meter in the direction perpendicular to the length of the test panel (i.e., the direction of brushing), and the B3 of each test area was recorded. The gloss loss ΔB of each sample was calculated as a percentage according to the following formula:

[0082] ΔB = (B1 - B3) / B1 * 100%; where B1 is the average value of the initial gloss and B3 is the average value of the final gloss; the smaller the gloss loss ΔB, the higher the wear resistance grade.

[0083] The test results are shown in Table 2.

[0084] Table 2

[0085] Test Project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 gloss 28° 22° 24° 25° 18° 23° 55° 45° Adhesion rating Level 2 Level 0 Level 0 Level 1 Level 0 Level 0 Level 1 Level 0 Abrasion resistance rating 45％ 32％ 35％ 41％ 28％ 34％ 39％ 20％

[0086] As can be seen from Examples 1-5, the introduction of polypropylene carbonate can significantly improve the adhesion of the repair paint, making the adhesion level of the repair paint reach 0-1, the gloss level drop to no more than 25°, the matte effect is good, the wear resistance is good, and the gloss loss is no more than 41% after repeated sanding.

[0087] As can be seen from Examples 2-8, component A is preferably composed of the following components in parts by weight: 50-55 parts of hydroxyl acrylic resin, 3-4 parts of matte powder, 6-8 parts of amino resin, 3-5 parts of polypropylene carbonate, 3-5 parts of pigment, 20-22 parts of solvent A, and 6-8 parts of additives. When the formulation of component A is within the above range, the gloss of the matte repair paint is in the range of 20-25°, the adhesion grade can reach 0, and the gloss loss after friction is small, the wear resistance is good, and the overall performance is better.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A low-temperature matte repair paint, characterized in that, It includes component A and component B. Component A includes the following components in parts by weight: 50-60 parts of hydroxy acrylic resin, 2-6 parts of matte powder, 2-10 parts of amino resin, 2-10 parts of pigment, 15-30 parts of solvent A, and 5-10 parts of additives. Component A further includes the following components in parts by weight: 2-10 parts of polypropylene carbonate; The preparation method of component A is as follows: mix and grind component A until the fineness is no greater than 1.5 μm to obtain component A; Component B comprises the following components in parts by weight: 40-50 parts isocyanate and 50-60 parts solvent B; Solvent A and solvent B may be the same or different organic solvents.

2. The low-temperature matte repair paint as described in claim 1, characterized in that, The organic solvent includes at least one of butyl acetate, ethyl acetate, 120# solvent oil, acetone, cyclohexanone, ethylene glycol butyl ether, xylene, and toluene.

3. The low-temperature matte repair paint as described in claim 1, characterized in that, The additives include at least one of wetting agents, anti-settling agents, and resistance additives.

4. The low-temperature matte repair paint as described in claim 1, characterized in that, The low-temperature matte repair paint includes the following additives in parts by weight: 1-5 parts wetting agent, 1-5 parts anti-settling agent, and 1-5 parts resistivity additive.

5. The low-temperature matte repair paint as described in claim 1, characterized in that, The weight ratio of component B to component A is (0.2-0.6):

1.

6. The low-temperature matte repair paint as described in claim 1, characterized in that, It also includes a diluent, wherein the mass ratio of the diluent to component A is (0.3-1):1, and the diluent includes at least one of butyl acetate, xylene, and toluene.

7. A method for online repair of dry film particle defects, characterized in that, Includes the following steps: S1. Inspect the matte paint dry film for particle defects; S2. Attach sandpaper to the grinding head of the electric grinder and use the electric grinder to rotate the sandpaper on the grinding head to grind the particle defects detected in step S1, so as to remove the particle protrusions and form a grinding defect area on the dry film surface. S3. Take the low-temperature matte repair paint as described in any one of claims 1-6, mix component A, component B and diluent, apply it to the sanding defect area formed in step S2, and the repair work is completed after drying.

8. The online repair method for dry film particle defects as described in claim 7, characterized in that, In step S2, the diameter of the grinding head of the electric polishing pen is 1-5mm, the grinding head speed is 4000-9000rpm, and the polishing time for each particle defect is 1-5s.

9. The online repair method for dry film particle defects as described in claim 7, characterized in that, In step S2, the abrasive grains on the sandpaper are 1000-3000 mesh.

Images