A self-cleaning coating for coils and its preparation method and application

Abstract

The invention discloses a coil self-cleaning coating, which is composed of the following components in parts by weight: 30-40 parts of high molecular weight polyester resin, 10-15 parts of fluorocarbon resin, 10-15 parts of self-matting resin, 15-20 parts of amino resin, 3-8 parts of antifouling agent, 0.2-1 parts of leveling agent, 0.1-0.5 parts of defoaming agent, 0.5-2 parts of rheological agent and 15-25 parts of solvent, wherein the high molecular weight polyester resin is one or more compositions of ETERKYD-5055-R-70, VYLON-637, GK-360 and ST-5790; the self-matting resin is MT-2350F or MT-2550F. The coil self-cleaning coating provided by the invention has excellent anti-graffiti effect, stain resistance, water resistance, flexibility, scratch resistance, oil resistance and high transparency.

Description

Technical Field

[0001] The invention belongs to the field of coatings, and in particular relates to a coiled material self-cleaning coating and a preparation method and application thereof. Background Art

[0002] Decorative coil coating is an emerging decorative coating in recent years. It is mostly used on substrates such as rolled aluminum and plastic film. Although decorative coatings have a colorful appearance, due to the objective conditions of the application scenarios of decorative coatings, external force majeure factors such as stains, oil stains, graffiti, scratches, etc. seriously affect the service life of decorative coil coatings and customer experience.

[0003] In summary, the market is in urgent need of a coil self-cleaning coating that can be applied to the surface of coils or coil decorative coatings to achieve anti-fouling and anti-graffiti effects while having high light transmittance without affecting the appearance of the decorative coating. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a self-cleaning coating for coils in view of the deficiencies in the prior art, which has excellent anti-graffiti effect, stain resistance, water resistance, flexibility, scratch resistance, oil resistance and high transparency.

[0005] To achieve the above technical purpose, the present invention provides a coil self-cleaning coating, which is composed of the following components in parts by weight: 30-40 parts of high molecular weight polyester resin, 10-15 parts of fluorocarbon resin, 10-15 parts of self-matting resin, 15-20 parts of amino resin, 3-8 parts of antifouling agent, 0.2-1 parts of leveling agent, 0.1-0.5 parts of defoaming agent, 0.5-2 parts of rheological agent and 15-25 parts of solvent, wherein the high molecular weight polyester resin is one or more of ETERKYD-5055-R-70, VYLON-637, GK-360 and ST-5790; the self-matting resin is MT-2350F or MT-2550F. When the amount of fluorocarbon resin added is large, due to the poor compatibility of the fluorocarbon resin itself, the light transmittance of the coating is reduced to, and due to the high surface tension of the fluororesin, the wettability of the coating is poor, and the substrate cannot be well wetted, and shrinkage holes or orange peels are easily generated. When the fluororesin content is reduced, the anti-graffiti effect will be reduced and its weather resistance will be worse. When the amount of self-matting resin added is too low, the matte effect may not be achieved, and when the amount added is too high, the transmittance is low; when the amount of anti-fouling additive added is 4%, the anti-graffiti level is level 2, and the anti-fouling effect is reduced. When the amount added is too high, due to its high surface tension, the wettability of the coating is poor, and it is easy to produce shrinkage holes or orange peel due to the inability to wet the substrate well, and the cost will also increase.

[0006] Among them, high molecular weight polyester resin is used, the molecular weight is 15000-20000, Tg is 30-50°C, the higher molecular weight provides excellent physical properties and adhesion for the coating, and the suitable glass transition temperature makes the coating have sufficient toughness and drying speed.

[0007] The fluorocarbon resin is a combination of one or more of HLR 670, ETERFLON-41215, ETERFLON-41011, and D-4109. The graft-modified parafluororesin is selected to improve weather resistance and antifouling performance while not easily generating a crystal structure to affect light transmittance.

[0008] The amino resin is MR625 or 5717. The use of methyl etherified amino resin can effectively increase the curing speed of the coating.

[0009] The antifouling agent is any one or more of TEGO-5000N, WELLMIX-6610, ZH-8017B or SMA 4015. The use of an organosilicon-modified anti-graffiti agent with a silanol group can ensure the long-term anti-graffiti effect of the coating.

[0010] The leveling agent is any one or more of BYK-333, TEGO 450 or BYK-306, and the leveling agent can ensure the flatness of the paint film during high-speed printing of the coating; the defoamer is BYK-052N or TEGO 945, which is used to eliminate bubbles and microbubbles generated during the dispersion, grinding and construction of the coating; the rheological additive is any one or more of VOK-SD, N-3300, AQH-810, which is used to improve the storage stability and anti-sagging performance of the coating.

[0011] The solvent is any one or more of xylene, trimethylbenzene, butyl acetate, dibasic acid ester, propylene glycol methyl ether acetate, and propylene glycol methyl ether. The fast-drying and slow-drying solvents are matched to balance the leveling effect and surface drying speed of the coating.

[0012] The present invention also provides a method for preparing the above coil self-cleaning coating, comprising the following steps:

[0013] S1: Add the formulated amount of high molecular weight polyester resin, fluorocarbon resin, self-matting resin and amino resin into a kettle in proportion and disperse at 600 RPM for 10 minutes, stirring evenly;

[0014] S2: Add the formulated amount of antifouling agent, leveling agent and defoaming agent to the system prepared in S1 in sequence, and disperse at 1000 RPM for 10 minutes;

[0015] S3: Add the formulated amount of rheological additive to the system prepared in S2, disperse at 1200RPM for 30 minutes, and disperse evenly. Finally, add the formulated amount of solvent to adjust the coating viscosity to 65-85KU.

[0016] The present invention further proposes the use of the coil self-cleaning paint in preparing coil self-cleaning coatings.

[0017] Specifically, the coating is roller-coated or sprayed on the coil and cured at 190-220° C. for 2-3 minutes to obtain the coil self-cleaning coating.

[0018] Beneficial effects: High molecular weight polyester resin, fluorocarbon resin and self-matting resin are used as matrix resins. High molecular weight polyester resin provides excellent flexibility and adhesion. The introduction of fluorocarbon resin can significantly improve the weather resistance and anti-graffiti effect of the coating. The self-matting resin reduces the gloss of the coating while ensuring that it still has a high light transmittance. At the same time, the addition of modified anti-graffiti additives causes Si-OH reaction to migrate to the surface of the coating during the film formation process, firmly anchored on the interface, and reduce the attenuation of the anti-graffiti effect. Finally, amino resin is added to the system as a cross-linking agent. Under high temperature conditions, the amino resin reacts with the hydroxyl group in the system to form a dense IPN structure, ensuring the excellent stability and adhesion of the paint film. At the same time, fast-drying and slow-drying solvents are used in combination, and PM with a lower boiling point is used to ensure that the volatility of the solvent promotes surface drying during the curing process of the coating. The slow-drying solvent BGA can promote the compatibility and mutual solubility between resins. The higher boiling point ensures the leveling of the coating within a limited time and provides better construction performance. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below through specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0020] Example 1

[0021] Ratio: 32 parts of polyester resin ETERKYD-5055-R-70, 1514 parts of fluorocarbon resin ETERFLON-412, 10 parts of self-matting resin MT-2350F, 571718 parts of amino resin, 105 parts of antifouling agent WELLMIX-66, 11 parts of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0022] Preparation method:

[0023] S1: Add high molecular weight polyester resin, fluorocarbon resin, self-matting resin and amino resin into a kettle in proportion, disperse at a low speed and stir evenly at a low speed.

[0024] S2: Add antifouling agent, leveling agent and defoaming agent to the system prepared in S1 in sequence, and stir quickly to make it uniform. S3: Add rheological agent to the system prepared in S2, disperse at medium and high speed for 30 minutes, disperse evenly, and finally add solvent to adjust the coating viscosity to 65-85KU, thus obtaining coil self-cleaning coating.

[0025] Example 2

[0026] Ratio: 28 parts of polyester resin ETERKYD-5055-R-70, 1518 parts of fluorocarbon resin ETERFLON-412, 12 parts of self-matting resin MT-2350F, 18 parts of amino resin 571718 parts, 104 parts of antifouling agent WELLMIX-66, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 16 parts of solvent PM, 2.2 parts of solvent BGA

[0027] Preparation method: Same as Example 1

[0028] Example 3

[0029] Ratio: 30 parts of polyester resin ETERKYD-5055-R-70, 1512 parts of fluorocarbon resin ETERFLON-412, 16 parts of self-matting resin MT-2350F, 571718 parts of amino resin, 103 parts of antifouling agent WELLMIX-66, 11 parts of leveling agent BYK-33, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0030] Preparation method: Same as Example 1

[0031] Example 4

[0032] Ratio: 26 parts of polyester resin ETERKYD-5055-R-70, 1514 parts of fluorocarbon resin ETERFLON-412, 10 parts of self-matting resin MT-2350F, 571720 parts of amino resin, 108 parts of antifouling agent WELLMIX-66, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 15 parts of solvent PM, 4 parts of solvent BGA

[0033] Preparation method: Same as Example 1

[0034] The self-cleaning coatings for coils of Examples 1-4 were tested according to the performance test indicators, and the results are shown in Table 1:

[0035] Table 1. Coil self-cleaning coating performance test

[0036]

[0037]

[0038] Comparative Example 1

[0039] Ratio: 32 parts of polyester resin ETERKYD-5055-R-70, 1518 parts of fluorocarbon resin ETERFLON-412, 31 parts of dispersant BYK-16, 14 parts of matting powder E-10, 571718 parts of amino resin, 105 parts of antifouling agent WELLMIX-66, 31 parts of leveling agent BYK-33, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0040] Preparation method:

[0041] S1: Add high molecular weight polyester resin, fluorocarbon resin, amino resin and dispersant into a kettle in proportion and disperse at a low speed, and stir evenly at a low speed; then add matting powder into the system and disperse to a fineness of ≤35μm.

[0042] S2: Add antifouling agent, leveling agent and defoaming agent to the system prepared in S1 in sequence, and stir quickly to make it uniform. S3: Add rheological agent to the system prepared in S2, disperse at medium and high speed for 30 minutes, disperse evenly, and finally add solvent to adjust the coating viscosity to 65-85KU, thus obtaining coil self-cleaning coating.

[0043] Comparative Example 2

[0044] Ratio: 32 parts of polyester resin ETERKYD-5055-R-70, 1514 parts of fluorocarbon resin ETERFLON-412, 10 parts of self-matting resin MT-2350F, 18 parts of amino resin 571718 parts, 5 parts of antifouling agent ZH-8017B, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0045] Preparation method: Same as Example 1

[0046] Comparative Example 3

[0047] Ratio: 32 parts of polyester resin ETERKYD-5055-R-70, 1514 parts of fluorocarbon resin ETERFLON-412, 10 parts of self-matting resin MT-2350F, 18 parts of amino resin MR 625, 105 parts of antifouling agent WELLMIX-66, 11 parts of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0048] Preparation method: Same as Example 1

[0049] Comparative Example 4

[0050] Ratio: 2 parts of polyester resin ETERKYD-5055-R-703, 14 parts of fluorocarbon resin D-4109, 10 parts of self-matting resin MT-2350F, 18 parts of amino resin 5717, 5 parts of antifouling agent WELLMIX-6610, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, 6.2 parts of solvent BGA

[0051] Preparation method: Same as Example 1

[0052] Test results

[0053] The self-cleaning coatings for coils of Example 1 and Comparative Examples 1-4 were tested according to the performance test indicators, and the results are shown in Table 1:

[0054] Table 1. Coil self-cleaning coating performance test

[0055]

[0056] It can be seen from the data in Table 1 that when matting powder is used to replace matting resin to matt the coating, since the matting powder mainly diffuses the light through the rough structure of the surface to form a matte effect, although the matting effect is better than the matting resin, the matting powder itself has a coarse particle size. While playing a diffuse reflection role, it also has a greater impact on the transmittance of light, causing the paint film to be foggy and misty, and the appearance of the decorative primer cannot be fully displayed. In addition, since the matting powder is distributed on the surface of the coating, the anti-graffiti additive cannot fully migrate to the coating surface, making the anti-fouling and anti-graffiti effect poor (the defect of comparative example 1). While using self-matting resin, since it uses the microphase incompatibility principle to produce a matting effect, the resin molecular chain will not produce oriented crystallization and affect the transmittance, and secondly, it is uniformly dispersed in the paint film as a matrix resin and will not affect the migration of the anti-graffiti additive to the surface. In addition, compared with the same terminal hydroxyl siloxane (WELLMIX-6610), the common modified silicone anti-graffiti additive (ZH-8017B) performs poorly in the anti-graffiti effect attenuation resistance. Although modified silicone can also migrate and arrange on the coating surface during the film-forming stage, the migration is mainly due to physical migration caused by its low surface energy. It cannot be completely anchored on the coating surface, and as time goes by, its effective ingredients will decrease on the surface (the defect of comparative example 2). However, after migrating to the surface, the terminal hydroxyl siloxane is firmly anchored on the surface of the paint film through the amino reaction, and will not decay significantly over time. Due to the large steric hindrance effect, the methyl etherified amino resin cannot fully react and cross-link with the resin within the limited curing time, resulting in the phenomenon of re-sticking and paint peeling during the curing and hot storage process of the coiled material. The steric hindrance effect of the semi-methyl etherified amino resin is less affected, the curing reaction speed is fast, and the reaction degree is complete. The above problems will not occur (the defect of comparative example 3, the use of methyl etherified amino resin, incomplete curing, resulting in re-sticking of the coating). From Comparative Example 4, it can be seen that tetrafluorocarbon resin (other embodiments are grafted modified parafluorocarbon resin) is used. Since the tetrafluorocarbon resin has a symmetrical structure and good crystallinity, it forms a crystalline structure with high regularity after cross-linking, has high strength, but poor toughness and poor bending resistance. The crystalline structure leads to low transmittance of the paint film and fogging of the coating.

[0057] This product is a functional green environmentally friendly coating, which has excellent anti-fouling function and uses environmentally friendly non-toxic solvents to reduce the pollution of the coating construction to the environment and the physical harm of the construction workers. This technology introduces self-matting resin, anti-graffiti additives with specific structures, and semi-methyl etherified amino resin that takes into account the curing efficiency and performance requirements. While ensuring the functionality and high transmittance of the coating, it also ensures the feasibility of its construction and practical application. This product has an anti-graffiti effect level of 1, a UV transmittance of ≥85%, and has the advantages of excellent flexibility and adhesion, which improves the service life and application field of coil coatings.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A self-cleaning coating for coiled materials, characterized in that: The invention is composed of the following components in parts by weight: 30-40 parts of high molecular weight polyester resin, 10-15 parts of fluorocarbon resin, 10-15 parts of self-matting resin, 15-20 parts of amino resin, 3-8 parts of antifouling agent, 0.2-1 parts of leveling agent, 0.1-0.5 parts of defoaming agent, 0.5-2 parts of rheological agent and 15-25 parts of solvent, wherein the high molecular weight polyester resin is ETERKYD-5055-R-70; the self-matting resin is MT-2350; the fluorocarbon resin is ETERFLON-41215; the amino resin is 5717; the antifouling agent is WELLMIX-6610; the leveling agent is BYK-333; the defoaming agent is BYK-052N; and the rheological agent is N-3300.

2. A self-cleaning coating for coiled materials, characterized in that: It is composed of the following components in parts by weight: 32 parts of polyester resin ETERKYD-5055-R-70, 14 parts of fluorocarbon resin ETERFLON-41215, 10 parts of self-matting resin MT-2350, 18 parts of amino resin 5717, 5 parts of anti-fouling agent WELLMIX-6610, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, and 6.2 parts of solvent BGA.

3. A self-cleaning coating for coiled materials, characterized in that: It is composed of the following components in parts by weight: 28 parts of polyester resin ETERKYD-5055-R-70, 18 parts of fluorocarbon resin ETERFLON-41215, 12 parts of self-matting resin MT-2350, 18 parts of amino resin 5717, 4 parts of anti-fouling agent WELLMIX-6610, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 16 parts of solvent PM, and 2.2 parts of solvent BGA.

4. A self-cleaning coating for coiled materials, characterized in that: It is composed of the following components in parts by weight: 30 parts of polyester resin ETERKYD-5055-R-70, 12 parts of fluorocarbon resin ETERFLON-41215, 16 parts of self-matting resin MT-2350, 18 parts of amino resin 5717, 3 parts of anti-fouling agent WELLMIX-6610, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 12.4 parts of solvent PM, and 6.2 parts of solvent BGA.

5. A self-cleaning coating for coiled materials, characterized in that: It is composed of the following components in parts by weight: 26 parts of polyester resin ETERKYD-5055-R-70, 14 parts of fluorocarbon resin ETERFLON-41215, 10 parts of self-matting resin MT-2350, 20 parts of amino resin 5717, 8 parts of anti-fouling agent WELLMIX-6610, 1 part of leveling agent BYK-333, 0.4 parts of defoaming agent BYK-052N, 1 part of rheological additive N-3300, 15 parts of solvent PM, and 4 parts of solvent BGA.

6. The method for preparing the coil self-cleaning coating according to any one of claims 1 to 5, characterized in that: The steps include: S1: Add the formulated amount of high molecular weight polyester resin, fluorocarbon resin, self-matting resin and amino resin into a kettle in proportion and disperse at 600 RPM for 10 minutes, stirring evenly; S2: Add the formulated amount of antifouling agent, leveling agent and defoamer to the system prepared in S1 in sequence, and disperse at 1000 RPM for 10 minutes; S3: Add the formulated amount of rheological additive to the system prepared in S2, disperse at 1200 RPM for 30 minutes, and disperse evenly. Finally, add the formulated amount of solvent to adjust the coating viscosity to 65-85KU.

7. Use of the coil self-cleaning paint according to any one of claims 1 to 5 in the preparation of coil self-cleaning coatings.

8. The use according to claim 7, characterized in that: The coating according to any one of claims 1 to 5 is roller-coated or sprayed on a coil and cured at 190-220° C. for 2-3 minutes to obtain a coil self-cleaning coating.

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