Epoxy primer-topcoat coating for engine surface and preparation method of epoxy primer-topcoat coating

Abstract

The invention relates to the technical field of water-based coatings, in particular to an epoxy primer-topcoat coating for the surface of an engine and a preparation method of the epoxy primer-topcoat coating, and the epoxy primer-topcoat coating comprises a component A and a component B in a weight ratio of 1: 1, the component A comprises the following raw materials in percentage by weight: 10.0% of a water-based amine curing agent; 36.0% of pure water; 2.0% of a dispersant; 0.5% of a defoaming agent; 15.0% of a pigment; 28.0% of a filler; 5.0% of an organic solvent; 2.0% of an anti-flash rust agent; 1.0% of a wetting agent; 0.5% of a thickening agent; the component B is prepared from the following raw materials: 65.0 to 75.0 percent of epoxy dispersion 1; 10.0 to 20.0% of an epoxy dispersion 2; and 15.0% of water-based acrylic resin. Compared with the prior art, the adhesive force of the coating on a base material is remarkably improved by selecting the epoxy resin of a specific type and adjusting the proportion of different epoxy resins, and meanwhile, the proper water-based acrylic resin is added, so that the miscibility with an epoxy dispersion is improved, and the adhesive force of the coating on the base material is improved. And the aging resistance of the coating film and the adhesive force of the base material are further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of water-based coatings, and in particular to an epoxy primer-top coating for an engine surface and a preparation method thereof. Background Art

[0002] The water-based coatings currently used by engine OEMs are basically water-based epoxy systems or water-based polyurethane systems. These two systems have their own advantages, but they also have limitations. Water-based epoxy system coatings are favored for their excellent chemical resistance and salt spray resistance, but they are not as good as water-based polyurethane systems in terms of aging resistance. On the contrary, water-based polyurethane system coatings are highly praised for their excellent flexibility and aging resistance, but they may be slightly inferior in terms of salt spray resistance. This makes it difficult to meet the dual requirements of aging resistance and salt spray resistance at the same time in practical applications, and at the customer's site, the compatibility issues of different substrates also limit the application of coatings, and cannot fully cover the needs of all substrates at the customer's site.

[0003] The invention patent with Chinese patent publication number CN114437610A discloses a water-based two-component epoxy primer-top coating and a preparation method thereof. The water-based two-component epoxy primer-top coating prepared in the patent has excellent salt spray resistance, but its aging resistance and compatibility with different substrates still need to be further improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide an epoxy primer-top coating for engine surface and a preparation method thereof, so as to solve the problem that the water-based coatings on the market can only have one of the aging resistance and salt spray resistance and have poor adaptability to different substrates.

[0005] In order to achieve the above object, the present invention is designed to provide an epoxy primer-top coating for an engine surface, comprising a component A and a component B in a weight ratio of 1:1; Component A includes the following raw materials by weight percentage: Water-based amine curing agent 10.0%; Pure water 36.0%; Dispersant 2.0%; Defoaming agent 0.5%; Pigment 15.0%; Filler 28.0%; Organic solvent 5.0%; Anti-flash rust agent 2.0%; Wetting agent 1.0%; Thickener 0.5%; Component B includes the following raw materials by weight percentage: Epoxy dispersion 1 65.0-75.0%; Epoxy dispersion 2 10.0-20.0%; Water-based acrylic resin 15.0%.

[0006] Preferably, the epoxy dispersion 1 is a quick-drying epoxy, and the epoxy dispersion 2 is a modified flexible epoxy.

[0007] Preferably, the water-based acrylic resin has a MFFT ≤ 50°C.

[0008] Preferably, the pigment is selected from titanium dioxide, phthalocyanine blue and the like.

[0009] Preferably, the filler is selected from one or more of mica powder, talc powder, barite powder and glass powder.

[0010] Preferably, the dispersant is a nonionic dispersant, the defoamer includes a silicone defoamer and an emulsified defoamer, the organic solvent is BCS, PNB, DPNB or a mixture of the two, the wetting agent is an acetylenic diol type wetting agent, the water-based amine curing agent is a polyamide, an aromatic amine or a mixture of the two, and the anti-flash rust agent is HALOXFLASH-X 150.

[0011] The present invention also provides a method for preparing an epoxy primer-top coating for an engine surface, comprising the following steps: S1. Take all the aqueous amine curing agent, dispersant and defoamer, dissolve in part of deionized water, and disperse in a disperser at a speed of 500-800r / min for 15-20min to obtain a premixed solution; S2. The disperser speed is adjusted to 300-400r / min, and pigment and filler are added to the premixed liquid to obtain a pigment mixture; S3 continue to disperse the pigment mixture, dispersed in a disperser at a speed of 2000-3000r / min for 30min, and the remaining deionized water was added during the dispersion process to obtain a pre-grinded mixture; S4. The pre-grinded mixture was continuously ground, the grinding medium was zirconium oxide beads, and after grinding, it was added to the pull cylinder, and an organic solvent, an anti-flash rust agent, a wetting agent, and a thickener were sequentially added in a dispersed state at 300-400r / min to obtain component A; S5. The epoxy dispersion 1, epoxy dispersion 2, and water-based acrylic resin were stirred and mixed in a container to obtain component B; S6. Mix component A and component B in a weight ratio of 1:1 to obtain the epoxy primer and surface all-in-one coating.

[0012] Preferably, the particle size of the zirconia beads is 1.2-1.5 mm.

[0013] Compared with the prior art, the present invention significantly improves the adhesion of the coating on the substrate by selecting a specific type of epoxy resin and adjusting the ratio between different epoxy resins. At the same time, the addition of a suitable water-based acrylic resin not only improves the miscibility with the epoxy dispersion, but also further enhances the aging resistance of the coating and the substrate adhesion. DETAILED DESCRIPTION

[0014] In order to make the purpose and principle of the present invention more clear, it is further described below in conjunction with specific embodiments.

[0015] Example 1-2 This embodiment provides an epoxy primer-top coating for the engine surface, including a component formula table as described in Table 1, in units of weight percentage, and the materials are prepared according to the contents of Table 1.

[0016] Epoxy dispersion 1 uses EP136 from Guangdong Qirun New Materials Co., Ltd., epoxy dispersion 2 uses EP146 from Guangdong Qirun New Materials Co., Ltd., water-based acrylic resin uses PA-4867 from Guangzhou Guanzhi New Materials Technology Co., Ltd., dispersant uses BYK190, defoamer uses tego 810, pigment uses LR-996 from Longmang, filler uses 1250 mesh precipitated barium sulfate, organic solvent uses BCS, wetting agent uses Evonik Dynol 607, thickener uses RHEOLATE®299 from Haimingsdeqian, water-based amine curing agent uses EH3510 from Guangdong Qirun New Materials Co., Ltd., and anti-flash rust agent uses HALOX FLASH-X 150.

[0017] Table 1

[0018] The preparation method of Example 1-2 is as follows: S1. Take all the aqueous amine curing agent, dispersant and defoamer, dissolve in part of deionized water, and disperse in a disperser at a speed of 500-800r / min for 15-20min to obtain a premixed solution; S2. The disperser speed is adjusted to 300-400r / min, and pigment and filler are added to the premixed liquid to obtain a pigment mixture; S3 continue to disperse the pigment mixture, dispersed in a disperser at a speed of 2000-3000r / min for 30min, and the remaining deionized water was added during the dispersion process to obtain a pre-grinded mixture; S4. The pre-grinded mixture was continuously ground, the grinding medium was zirconium oxide beads, and after grinding, it was added to the pull cylinder, and organic solvent, anti-flash rust agent, wetting agent, thickener were sequentially obtained in a dispersed state at 300-400r / min to obtain component A; S5. The epoxy dispersion 1, epoxy dispersion 2, and water-based acrylic resin were stirred and mixed in a container to obtain component B; S6. Mix component A and component B in a weight ratio of 1:1 to obtain the epoxy primer and surface all-in-one coating.

[0019] Comparative Example Comparative Example 1 is a commercially available two-component epoxy bottom-surface integrated product, and Comparative Example 2 is a commercially available two-component polyurethane bottom-surface integrated product.

[0020] Performance Testing The epoxy primer and surface coating prepared in Example 1-2 was sprayed using a Yantian W101 air spray gun, leveled at room temperature for 10 minutes, and baked at 80°C for 30 minutes. The sprayed substrates were cold-rolled plates, different substrates, and plates with different primers. Specific test data are shown in the table below.

[0021] Example topcoat performance test results:

[0022]

[0023] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical solutions and novel concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An epoxy primer-top coating for engine surface, characterized in that: comprising a component A and a component B in a weight ratio of 1:1; Component A includes the following raw materials by weight percentage: Water-based amine curing agent 10.0%; Pure water 36.0%; Dispersant 2.0%; Defoaming agent 0.5%; Pigment 15.0%; Filler 28.0%; Organic solvent 5.0%; Anti-flash rust agent 2.0%; Wetting agent 1.0%; Thickener 0.5%; Component B includes the following raw materials by weight percentage: Epoxy dispersion 1 65.0-75.0%; Epoxy dispersion 2 10.0-20.0%; Water-based acrylic resin 15.0%.

2. An epoxy primer-top coating for engine surface as claimed in claim 1, characterized in that: The epoxy dispersion 1 is a quick-drying epoxy, and the epoxy dispersion 2 is a modified flexible epoxy.

3. An epoxy primer-top coating for engine surface as claimed in claim 1, characterized in that: The water-based acrylic resin has a MFFT of ≤50°C.

4. The epoxy primer-top coating for engine surface as claimed in claim 1, characterized in that: The pigment is selected from titanium dioxide and phthalocyanine blue.

5. The epoxy primer-top coating for engine surface as claimed in claim 1, characterized in that: The filler is selected from one or more of mica powder, talc powder, barite powder and glass powder.

6. An epoxy primer-top coating for engine surface as claimed in claim 1, characterized in that: The dispersant is a non-ionic dispersant. The defoamer includes silicone defoamer and emulsified defoamer. The organic solvent is BCS, PNB, DPNB or a mixture of the two. The wetting agent is an acetylenic diol type wetting agent, The water-based amine curing agent is a curing agent of polyamide, aromatic amine or a mixture of the two. The anti-flash rust agent is HALOX FLASH-X 150.

7. A method for preparing an epoxy primer-top coating for an engine surface as claimed in claim 1, characterized in that: The steps include: S1. Take all the aqueous amine curing agent, dispersant and defoamer, dissolve in part of deionized water, and disperse in a disperser at a speed of 500-800r / min for 15-20min to obtain a premixed solution; S2. The disperser speed is adjusted to a low speed, and pigments and fillers are added to the premixed liquid to obtain a pigment mixture; S3. Continue to disperse the pigment mixture, disperse at high speed in a disperser for 30 min, and add the remaining deionized water during the dispersion process to obtain a pre-grinded mixture; S4. The pre-grinded mixture is continuously ground, the grinding medium is zirconia beads, and after grinding, it is added to the pull cylinder, and an organic solvent, an anti-flash rust agent, a wetting agent, and a thickener are sequentially added in a low-speed dispersion state to obtain component A; S5. The epoxy dispersion 1, epoxy dispersion 2, and water-based acrylic resin were stirred and mixed in a container to obtain component B; S6. Component A and component B are mixed in a weight ratio of 1:1 to obtain the epoxy primer-top coating for the engine surface.

8. A method for preparing an epoxy primer-top coating for an engine surface as claimed in claim 7, characterized in that: The particle size of the zirconia beads is 1.2-1.5 mm.

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