Fluorine-free super-hydrophobic weather-resistant material and application method thereof

Abstract

The invention discloses a fluorine-free super-hydrophobic weather-resistant top coating material and an application method thereof. The material is composed of a component A and a component B, the component A comprises the following components in percentage by weight: 1-100% of weather-resistant epoxy resin, 1-4% of polyethylene micro powder, 0.5-20% of hydrophobic modified micro powder, 0-10% of a hydrophobic aid, 0-10% of other aids and the balance of an organic solvent A; based on 100% of the component B, the component B comprises 1-100% of a curing agent and the balance of an organic solvent B; the mass ratio of the component A to the component B is (1: 99)-(99: 1). After the component A and the component B are mixed, the mixture is sprayed, dip-coated or brushed on paint or a metal substrate, and a film can be formed through natural drying or thermocuring. On the premise that the prepared top coat does not contain fluorine, the top coat still has excellent weather resistance and hydrophobic and oleophobic capacities; and the top coat is matched with the zinc-aluminum coating primer for use, so that the anti-corrosion capability of the composite coating can be greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and relates to a fluorine-free superhydrophobic weather-resistant material and an application method thereof. Background Art

[0002] At present, zinc-aluminum coatings are commonly used as anti-corrosion coatings for components such as automobile fuel tank oil pipes, and have excellent anti-corrosion performance. However, due to the poor oil resistance of zinc-aluminum coatings, an oil-proof topcoat needs to be applied over the zinc-aluminum coatings.

[0003] CN 113512336B discloses a two-component weather-resistant, hydrophobic and oleophobic topcoat. The topcoat composition consists of component A and component B; calculated by the percentage of the total mass of component A, component A includes: weather-resistant epoxy resin 1-100%, polytetrafluoroethylene 0-10%, hydrophobic auxiliary agent 0-10%, other auxiliary agents 0-10%, and organic solvent A is made up to 100%; calculated by the percentage of the total mass of component B, component B includes: curing agent 1-100%, and organic solvent B is made up to 100%; the mass ratio of component A to component B is 1:99 to 99:1. After component A and component B are mixed, they are sprayed, dip-coated or brushed on a paint or metal substrate, and can form a film by natural drying or heat curing; the obtained topcoat has excellent weather resistance and hydrophobic and oleophobic capabilities; and when this topcoat is used in combination with a zinc-aluminum coating primer, the anti-corrosion ability of the composite coating can be greatly improved. However, this solution uses perfluorosilicic acid and PTFE micropowder, which does not meet the increasingly stringent environmental requirements. For example, the European Union requires that starting from 2025, coatings and interfacial materials do not contain PFAS. Summary of the Invention

[0004] The purpose of the present invention is to provide a fluorine-free superhydrophobic weather-resistant material and an application method thereof to meet the demand for zinc-aluminum coating-matched topcoat materials without PFAS; on the basis of meeting the performance of CN 113512336B, it does not contain PFAS raw materials.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] The present invention relates to a fluorine-free superhydrophobic weather-resistant topcoat material, and the material consists of component A and component B;

[0007] Calculated by the percentage of the total mass of component A, component A includes:

[0008]

[0009]

[0010] The hydrophobic modified micropowder is hydrophobic modified silica micropowder or hydrophobic modified diatomite;

[0011] Component B includes, by percentage of the total mass of Component B:

[0012] Curing agent 1 - 100%,

[0013] Organic solvent B to make up 100%;

[0014] The mass ratio of Component A to Component B is 1:99 to 99:1;

[0015] The curing agent is one or a mixture of a fatty amine modified with a long-chain alkyl acid and an alicyclic amine modified with a long-chain alkyl acid.

[0016] The specific mixing ratio of Component A and Component B is preferably (1 - 1.5):1 according to the epoxy equivalent of "weather-resistant epoxy resin" / amine equivalent of "curing agent".

[0017] As an embodiment of the present invention, the long-chain alkyl acid refers to a straight-chain or branched-chain alkyl acid with C5 - C9. Preferably, the long-chain alkyl acid is one or a combination of valeric acid, caproic acid, octanoic acid, heptanoic acid, and nonanoic acid.

[0018] As an embodiment of the present invention,

[0019] Component A includes, by percentage of the total mass of Component A:

[0020]

[0021] Component B includes, by percentage of the total mass of Component B:

[0022] Curing agent 1 - 100%,

[0023] Organic solvent B to make up 100%;

[0024] The mass ratio of Component A to Component B is 1:99 to 99:1.

[0025] As an embodiment of the present invention, the weather-resistant epoxy resin is an epoxy resin without weather-unresistant functional groups; the weather-unresistant functional groups include double bonds, triple bonds, and benzene rings. Hydrogenated epoxy resin is preferably selected, such as EPONEX Resin 1510 from Hexion. Its mass ratio in Component A is 1 - 100%, and more preferably 40 - 60%.

[0026]

[0027] As an embodiment of the present invention, the polyethylene micropowder has a D90 particle size < 5 μm. Its mass ratio in Component A is 1 - 4%, and more preferably 2 - 4%.

[0028] As an embodiment of the present invention, the D50 particle size of the hydrophobic modified micropowder is 1-5 μm. If the particle size is too small, the oil absorption amount is too large, which affects the addition amount and the oil and water repellent effects of the final material. Its mass ratio in component A is 0.5-20%, and more preferably 10-15%.

[0029] As an embodiment of the present invention, the hydrophobic aid is selected from fluorine-free hydrophobic silanes.

[0030] As an embodiment of the present invention, the hydrophobic aid is selected from one or a combination of several kinds of alkyl silanes. Its mass ratio in component A is 0-10%, and more preferably 3-5%. It includes vinyltriethoxysilane, vinyltrimethoxysilane, octadecylsilane, etc.

[0031] As an embodiment of the present invention, the other aids are selected from one or a combination of several kinds of dispersants, defoamers, wetting agents, thickeners, drying accelerators, and leveling agents. Its mass ratio in component A is 0-10%, and more preferably 2-5%.

[0032] As an embodiment of the present invention, the organic solvent A is selected from one or a combination of several kinds of aromatic solvents, alkane solvents, ketone solvents, alcohol solvents, and ester solvents. The aromatic solvents include xylene, ethylbenzene, toluene, 100# solvent oil, 150# solvent oil, etc.; the alkane solvents include petroleum ether, n-hexane, n-pentane, etc.; the ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; the alcohol solvents include ethanol, butanol, isopropanol, etc.; the ester solvents include ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, etc. It is preferably to use a mixture of aromatic solvents, ketone solvents, and alcohol solvents.

[0033] As an embodiment of the present invention, the curing agent is a self-synthesized curing agent, which is a long-chain alkyl acid-modified aliphatic amine and / or a long-chain alkyl acid-modified alicyclic amine. Among them, the aliphatic amine is selected from one or a combination of several kinds of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. The long-chain alkyl acid is a combination of one or more of valeric acid, hexanoic acid, octanoic acid, heptanoic acid, and nonanoic acid. Preferably, n-hexanoic acid and n-heptanoic acid are used as the modification raw materials. The mass percentage of the self-synthesized curing agent in component B is 1-100%. Considering the problems of the viscosity of component B and the convenience of production, a more preferred choice is 50-80%.

[0034] As an embodiment of the present invention, the organic solvent B is selected from one or a combination of aromatic solvents, alkane solvents, ketone solvents, alcohol solvents, and ester solvents. The aromatic solvents include xylene, ethylbenzene, toluene 100# solvent oil, 150# solvent oil, etc.; the alkane solvents include petroleum ether, n-hexane, n-pentane, etc.; the ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; the alcohol solvents include ethanol, butanol, isopropanol, isobutanol, etc.; the ester solvents include ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, etc. A mixture of aromatic solvents, ketone solvents, and alcohol solvents is preferably used.

[0035] The present invention also relates to an application method of the fluorine-free superhydrophobic weather-resistant topcoat material, which is obtained by spraying, dipping, or brushing any of the foregoing topcoat materials on the surface of paint or a metal substrate.

[0036] As an embodiment of the present invention, after spraying, dipping, or brushing, it is naturally dried or baked at medium and low temperatures until it is completely cured into a film. In a specific implementation, it is naturally dried for at least 4 hours to be completely cured into a film; or baked at 80 °C for at least 30 minutes to be completely cured into a film.

[0037] As an embodiment of the present invention, the paint is a zinc-aluminum coating primer. The topcoat material of the present invention is used in combination with the zinc-aluminum coating primer, which can greatly improve the corrosion resistance of the composite coating.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1) In the system of the present invention, while the long-chain alkyl acid-modified amine curing agent enhances the hydrophobicity, the hydrophobic modified micropowder forms a micron-level papilla structure similar to the surface of a lotus leaf on the coating surface, forming a "lotus leaf effect"; at the same time, the PE micropowder floats to the coating surface, reducing the surface tension and the rolling resistance of water droplets on the coating surface.

[0040] 2) In the system of the present invention, a long-chain alkyl acid-modified amine curing agent is used, which is combined with polyethylene micropowder and hydrophobic modified micropowder, so that the prepared topcoat still has excellent weather resistance and hydrophobic and oleophobic capabilities without fluorine; and when the topcoat is used in combination with the zinc-aluminum coating primer, it can greatly improve the corrosion resistance of the composite coating and make the composite coating have good weather resistance. Description of the Drawings

[0041] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more obvious:

[0042] Figure 1 It is the nuclear magnetic carbon spectrum of the n-heptanoic acid-modified tetraethylenepentamine curing agent;

[0043] Figure 2 13C NMR spectrum of the curing agent modified with n-heptanoic acid

[0044] Figure 3 13C NMR spectrum of the curing agent modified with n-hexanoic acid Detailed implementation manners

[0045] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0046] In the following embodiments, the preparation of the topcoat composition: After the respective components of the topcoat composition are physically mixed, they are uniformly mixed by high-speed dispersion. Then it can be used for performance testing.

[0047] Taking the modification of tetraethylenepentamine with n-heptanoic acid as an example, the modification mechanism is as follows:

[0048]

[0049] The film-forming mechanism of the topcoat material curing is as follows:

[0050]

[0051] Preparation of test plates: Unless otherwise specified, the test plates are Q-panel cold-rolled steel plates with a 10-μm dry film of ST112 zinc-aluminum coating from Shanghai Kuyao New Materials Co., Ltd. The test plates are degreased and cleaned with a degreasing agent and dried for standby. The topcoat is applied to the pretreated test plates by air spraying. After curing, the relevant properties are tested. The adhesion test is carried out in accordance with the standard of GB / T 9286-1998, and the anti-corrosion ability is evaluated by testing the neutral salt spray resistance performance according to the standard of GB / T 1771-2007. The water droplet contact angle is obtained by droplet shape analysis (DSA) with a contact angle measuring instrument. QUV is carried out in accordance with the standard of ISO 11507-2007.

[0052] Example 1

[0053] This example relates to a fluorine-free superhydrophobic and weather-resistant topcoat material, and its composition and mass dosage are as shown in Table 1 below:

[0054] Table 1

[0055]

[0056] Remarks: 1 Hexion hydrogenated epoxy resin, epoxy equivalent 210 g / mol,

[0057] 2 Purchased from Tian Shi Wax Powder Co., Ltd., with an average particle size D50 of 3 μm and D90 particle size < 5 μm.

[0058] 3 Purchased from Hoffmann of Germany, hydrophobic modified silica fine powder, with D50 particle size of 3 μm.

[0059] 4 Evonik's hydrophobic silane

[0060] 5 Evonik's hydrophobic modified fumed silica

[0061] 6，7 Purchased from Sinopec Shell Company

[0062] 8 Curing agent a, which is n - heptanoic acid modified tetraethylenepentamine. Its synthesis raw materials: the molar mass ratio of n - heptanoic acid to tetraethylenepentamine is 2:1; the reaction temperature is 120 °C. The amine equivalent of curing agent a is 82.6 g / mol, and the structure is as follows:

[0063] 1H NMR is as Figure 1 .

[0064] 9 Curing agent b, which is n - heptanoic acid modified diethylenetriamine. Its synthesis raw materials: the molar mass ratio of n - heptanoic acid to diethylenetriamine is 2:1; the reaction temperature is 120 °C. The amine equivalent of curing agent b is 109 g / mol, and the structure is as follows:

[0065] 1H NMR is as Figure 2 .

[0066] 10 Curing agent c, which is n - hexanoic acid modified diethylenetriamine. Its synthesis raw materials: the molar mass ratio of n - hexanoic acid to diethylenetriamine is 2:1; the reaction temperature is 120 °C. The amine equivalent of curing agent c is 100 g / mol, and the structure is as follows:

[0067] 1H NMR is as Figure 3 . The performance test results are as shown in Table 2 - Table 5:

[0068] Table 2

[0069]

[0070] Table 3

[0071]

[0072] Table 4

[0073]

[0074]

[0075] Table 5

[0076]

[0077]

[0078] Comparative Examples 1-3

[0079] Comparative Examples 1-3 were adjusted based on the fluorine-free superhydrophobic weather-resistant topcoat material of Example 1, and their compositions and mass dosages are as shown in Table 6 below:

[0080] Table 6

[0081]

[0082]

[0083]

[0084] In summary, in the system of the present invention, a long-chain alkyl acid-modified amine curing agent is used, which is combined with polyethylene micropowder and hydrophobic modified micropowder, so that the prepared topcoat still has excellent weather resistance and hydrophobic and oleophobic capabilities without fluorine; and when this topcoat is used in combination with a zinc-aluminum coating primer, after curing and film formation, the composite coating has good weather resistance, hydrophobic and oleophobic properties, and extremely excellent anti-corrosion ability.

[0085] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A fluorine-free super-hydrophobic weather-resistant top coating material, characterized in that: The topcoat material is composed of component A and component B; in terms of percentage of the total mass of component A, component A includes: Weathering resistant epoxy resin 1-100%, Polyethylene micro powder 1-4%, Hydrophobic modified micro powder 0.5-20%, Hydrophobic additive 0-10%, Other additives 0-10%, The organic solvent A is made up to 100%; The hydrophobically modified micropowder is hydrophobically modified silicon micropowder or hydrophobically modified diatomaceous earth; Component B includes, as a percentage of the total mass of component B: Curing agent 1-100%, The organic solvent B is made up to 100%; The mass ratio of component A to component B is 1:99 to 99:1; The curing agent is one of long-chain alkyl acid-modified fatty amine and long-chain alkyl acid-modified alicyclic amine, or a mixture of the two.

2. The fluorine-free super-hydrophobic weather-resistant topcoat material according to claim 1, characterized in that: The weather-resistant epoxy resin is an epoxy resin that does not contain weather-resistant functional groups; the weather-resistant functional groups include double bonds, triple bonds and benzene rings.

3. The fluorine-free super-hydrophobic weather-resistant top coating material according to claim 1, characterized in that: The long-chain alkyl acid refers to a C5-C9 straight-chain or branched-chain alkyl acid.

4. The fluorine-free super-hydrophobic weather-resistant top coating material according to claim 1, characterized in that: The polyethylene micropowder is a polyethylene micropowder with a D90 particle size of less than 5 μm; and the hydrophobically modified micropowder has a D50 particle size of 1-5 μm.

5. The fluorine-free super hydrophobic weather-resistant top coating material according to claim 1, characterized in that: The hydrophobic auxiliary agent is selected from alkyl silane.

6. The fluorine-free super-hydrophobic weather-resistant top coating material according to claim 1, characterized in that: The other auxiliary agents are selected from one or a combination of dispersants, defoamers, wetting agents, thickeners, drying agents, and leveling agents.

7. The fluorine-free super-hydrophobic weather-resistant topcoat material according to claim 1, characterized in that: The organic solvent A is selected from one or a combination of aromatic solvents, alkane solvents, ketone solvents, alcohol solvents, and ester solvents.

8. The fluorine-free super-hydrophobic weather-resistant top coating material according to claim 1, characterized in that: The organic solvent B is selected from one or a combination of aromatic solvents, alkane solvents, ketone solvents, alcohol solvents, and ester solvents.

9. A method for applying a fluorine-free super-hydrophobic weather-resistant topcoat material, characterized in that: The surface coating material is obtained by spraying, dipping or brushing the surface coating material as described in any one of claims 1 to 8 on the surface of the paint or metal substrate.

10. The method for applying the fluorine-free super-hydrophobic weather-resistant topcoat material according to claim 9, characterized in that: After the topcoat material is sprayed, dipped or brushed, it is naturally dried or baked at medium to low temperature until it solidifies into a film.

Images