Process for the preparation of anti-stiction, stain resistant, lubricious, wear resistant coatings and layers

Abstract

The present application relates to the technical field of functional coating, in particular to a kind of anti-adhesion, stain-resistant, lubricated and wear-resistant coating and preparation method thereof, comprising, by mass percentage: 12-22% of self-quenching polyurethane resin emulsion; 30-40% of medium-soft polyurethane resin emulsion; 10-20% of water-based polyolefin resin emulsion; 2-6% of silicone dispersion water-based silicone emulsion; 2-6% of PTFE dispersion emulsion; 2-8% of high-silicon modified polyurethane emulsion; 1-5% of modified intermediate silicone resin emulsion; 1-12% of isocyanate curing agent and / or gamma-glycidyl ether oxypropyl trimethoxysilane; 1-6% of water; 0.0-0.5% of leveling agent; 0.0-1% of surfactant; 0.0-0.8% of thickening agent; 0-18% of cosolvent.The present application obtains a kind of temperature-resistant and wear-resistant coating by formula optimization, which has good adhesion and close adhesion on the surface of non-polar elastic substrate, and can adapt to the stretching of elastic substrate without peeling off.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional coating, in particular to a kind of anti-adhesion pollution lubrication wear-resistant coating and preparation method of coating. BACKGROUND

[0002] At present, the sealing ring of washing machine often appears mutual adhesion before installation, pollutant blockage of water outlet, easy breakage of sealing element connecting part and lip treatment, and is more prone to aging in the drum washing machine with heating and drying function, especially in the drum washing machine and when the rubber base material is EPDM rubber, the problem is more prominent. By coating a functional coating on the surface of the base material, the wear resistance and high temperature resistance of the sealing ring and other devices can be improved. The coating usually needs to have good adhesion with the base material to improve the service life of the coating.

[0003] The adhesion of the coating on the surface of the non-polar rubber base material is difficult to guarantee due to its elasticity and non-polar characteristics, and the coating is prone to cracking or peeling with the stretching and contraction of the base material. Therefore, the elasticity and adhesion of the coating for such base material also need to be improved to adapt to the elastic working state of the base material. Patent CN201910337663.5 discloses a functional waterborne polyurethane coating for EPDM rubber and a preparation method thereof, which is composed of A component and B component. When used, A component and B component are mixed in a mass ratio of 6-10:1, wherein A component is composed of waterborne hydroxyl acrylic dispersion, waterborne fluorocarbon emulsion, waterborne polyurethane dispersion, dispersing agent, titanium white, base material wetting agent, defoaming agent, thickening agent, adhesion promoter, hand feel additive, anti-graffiti additive and deionized water; B component is composed of HDI type isocyanate polymer, anhydrous diluent and dehydrating agent. The functional waterborne polyurethane coating for EPDM rubber has excellent adhesion to the surface of EPDM rubber, and the formed coating has good flexibility, smooth hand feel, small friction coefficient and significant self-cleaning effect. However, it needs to add an adhesion promoter, and its high temperature resistance is unknown. According to its composition, it is speculated that its temperature resistance does not exceed 120℃; its bending flexibility is only observed whether the paint film is broken through bending experiment, and the deformation amount of one bending is not large, so this degree of test cannot reflect the adaptability of the coating to elastic deformation.

[0004] Therefore, it is necessary to provide an improved anti-adhesion pollution lubrication wear-resistant coating and preparation method of coating to solve the problems of poor adhesion and adhesion of the coating for non-polar elastic base material, and poor temperature resistance. SUMMARY

[0005] The present application aims to provide an anti-adhesion pollution lubrication wear-resistant coating and preparation method of coating. Through formula optimization, a temperature-resistant and wear-resistant coating is obtained, which has good adhesion and adhesion on the surface of non-polar elastic base material and can adapt to the stretching of elastic base material without peeling.

[0006] To achieve the above object, the present application provides a kind of anti-adhesion pollution-resistant lubrication wear-resistant coating, by mass percentage includes the following components:

[0007]

[0008] Further, the high-silicon modified polyurethane emulsion is a silicone-modified aliphatic polyurethane emulsion, the mass percentage of silicone chain is 65-75%, preferably 68-72%, and the silicone chain can be polymethylsiloxane or polyphenylsiloxane, etc., which is copolymerized with aliphatic polyurethane chain;The solid content of the silicone-modified aliphatic polyurethane emulsion is 25-35%, preferably 28-32%.

[0009] Further, the modified intermediate silicone resin is a methoxy low molecular weight active silicone intermediate, and the molecular weight is 10000-20000.The solid content is 38-42%.

[0010] The high-silicon modified polyurethane emulsion and the modified intermediate silicone resin can both improve the temperature resistance of the coating. When only the high-silicon modified polyurethane emulsion is added, the temperature resistance is improved to 150℃ without falling off and the coating does not yellow. After adding the modified intermediate silicone resin, the long-term temperature resistance of the coating can reach 180℃.

[0011] Further, the water-based polyolefin resin emulsion is a water-based chlorinated polypropylene resin, and the solid content is 38-40%, and the chlorine content is 12-18%;The amount of the water-based polyolefin resin emulsion is 13-16%.This component can significantly improve the adhesion to non-polar substrates, especially improve the adhesion and adhesion of the coating to EPDM.If the water-based chlorinated polypropylene resin is not added, the adhesion is only level 2, and after adding, the adhesion can reach level 0-1.

[0012] Further, the solid content of the silicone dispersion water-based silicone emulsion is 75-85%, preferably 78-82%, and the particle size of the silicone dispersion is 100-300nm.The silicone dispersion is a white semi-transparent paste.Silicone dispersion is usually polymethylsiloxane, which has low surface energy, good affinity to non-polar substrates, and can improve self-cleaning function.Silicone dispersion can be filled between the pores of the coating to improve adhesion.

[0013] Further, the solid content of the PTFE dispersion emulsion is 55-65%, and the particle size of the PTFE dispersion is 100-300nm.The surface energy of PTFE dispersion is lower than that of silicone dispersion, which can play a similar role to silicone dispersion.

[0014] Further, the solid content of the self-extinguishing polyurethane resin emulsion is 30-33%, the solid content of the medium-soft polyurethane resin emulsion is 28-32%, and the self-extinguishing polyurethane resin and the medium-soft polyurethane resin are aliphatic polyester anionic polyurethane resins. Taking aliphatic polyester anionic polyurethane resin as the main body adhesive resin, the surface energy and affinity of the coating and the non-polar substrate (EPDM ternary ethylene-propylene rubber) can be solved and improved, and the adhesion can be improved; by compounding the self-extinguishing and medium-soft polyurethane resins in a certain proportion, the elongation, gloss and wear resistance requirements can be solved, and the tensile strength requirements of the coating on the rubber can be met.

[0015] The solvents of the emulsions involved in the components of the present application are all water. Preferably, the paint includes, according to the effective content of each component, 3.6-7.0% of the self-extinguishing polyurethane resin; 8.4-12% of the medium-soft polyurethane resin; 3.8-8% of the water-based polyolefin resin; 1.6-4.8% of the silicone dispersion water-based silicon; 1.2-3.6% of the PTFE dispersion; 1.4-5.6% of the high-silicon modified polyurethane; 1.4-3.5% of the modified intermediate silicone resin; 1-12% of the isocyanate curing agent and / or gamma-glycidyl ether oxypropyl trimethoxysilane; 30-78% of water; 0.0-0.5% of the leveling agent; 0.0-1% of the surfactant; 0.0-0.8 of the thickening agent; and 0-18% of the cosolvent.

[0016] Further, the addition of the isocyanate curing agent and / or gamma-glycidyl ether oxypropyl trimethoxysilane can increase the crosslinking density. The isocyanate curing agent is preferably BI220 latent curing agent, which can maintain the storage stability of the paint and make it possible to be made into a single component. The addition of the KH560 siloxane coupling agent can enhance the crosslinking density of the paint, improve the adhesion, reduce the baking temperature, improve the production efficiency, and make it possible to be cured at room temperature. The amounts of the two are set according to the requirements in actual application.

[0017] Further, the cosolvent is ethanol;

[0018] And / or, the leveling agent is an acrylate leveling agent;

[0019] And / or, the surfactant is polyoxyethylene-8-octylphenyl ether;

[0020] And / or, the thickening agent is one or more of hydroxypropyl methylcellulose, hydroxyethyl cellulose and polyurethane associated thickening agent.

[0021] Preferably, the following components are included according to the mass percentage:

[0022]

[0023]

[0024] The application also provides a preparation method of the anti-sticking, stain-resistant, lubricating and wear-resistant coating, which sprays the anti-sticking, stain-resistant, lubricating and wear-resistant coating according to any one of the above to the surface of a substrate, and solidifies to obtain the anti-sticking, stain-resistant, lubricating and wear-resistant coating. Preferably, the solidification is achieved by baking at 110-130 DEG C for 15-30 min, and the solidification can also be achieved at a lower temperature or even at room temperature by adjusting the formula, which is convenient for production operation, for example, using gamma-glycidoxypropyltrimethoxysilane as a curing agent.

[0025] The self-extinguishing and medium-soft polyurethane resin can ensure the basic elasticity of the coating, the high-silicon modified polyurethane emulsion and the modified intermediate silicone resin emulsion can synergistically improve the high-temperature resistance of the coating, the silicone dispersion aqueous silicone emulsion and the PTFE dispersion emulsion can fill into the pores of the polyurethane coating, and synergistically improve the anti-sticking lubricity, adhesion and stain resistance of the coating. The isocyanate curing agent and / or gamma-glycidoxypropyltrimethoxysilane can increase the crosslinking density, thereby enhancing the adhesion to the substrate, and can also accelerate the solidification film forming speed, reduce the baking temperature, and improve the production efficiency. Therefore, by the components and the ratio of the application, a coating with excellent adhesion, wear resistance and high-temperature resistance on a non-polar elastic substrate can be obtained.

[0026] Further, the thickness of the coating is 5-20 um.

[0027] Further, in order to be suitable for manual spraying or machine spraying, the coating is diluted with water or ethanol at a mass ratio of 1:0.2-1, and then preheated to 40-50 DEG C before being sprayed onto the surface of the substrate, so that a very smooth and complete coating film surface can be obtained.

[0028] Further, the substrate is a non-polar substrate, preferably a non-polar elastic substrate, and more preferably an EPDM rubber. EPDM, i.e. ethylene propylene diene rubber, is a saturated rubber and also a non-polar rubber, which has a relatively low surface energy and a large viscosity, and many materials cannot be attached thereto. Based on the fact that EPDM rubber is a non-polar substrate, the application uses an aliphatic polyester modified anionic polyurethane resin.

[0029] The application also provides an anti-sticking, stain-resistant, lubricating and wear-resistant coating prepared by the preparation method according to any one of the above. The coating is an anti-sticking, stain-resistant, lubricating and wear-resistant coating for a sealing ring door seal of a washing machine, which can withstand a temperature of 180 DEG C. After the anti-sticking, lubricating and wear-resistant coating for the sealing ring and the water blocking ring of the washing machine is sprayed onto the workpiece, low-temperature baking and solidification are performed, and the film after film forming has good adhesion, good wear resistance, excellent anti-sticking and stain resistance, and the effect of waterproof and easy cleaning.

[0030] The application has the following beneficial effects:

[0031] 1. The anti-sticking, stain-resistant, lubricating and wear-resistant coating provided by the present application is prepared by compounding a matting polyurethane resin and a medium-soft polyurethane resin, which meets the requirements of gloss, elasticity and hardness of the coating. The water-based polyolefin resin emulsion can complement the curing agent and siloxane coupling agent to further improve the adhesion of the coating to the substrate, cross-link to form a network structure, and improve the strength and wear resistance of the coating. The high-silicon modified polyurethane PA emulsion and the modified intermediate silicon resin ensure the slipperiness and non-stickiness of the coating, and greatly improve the temperature resistance of the coating, so that the coating can maintain its performance without falling off at 180 DEG C for a long time. The use of PTFE dispersion emulsion and silicone dispersion water-based silicone emulsion improves the slipperiness and assembly performance of the product, and improves the anti-sticking, anti-pollution, wear resistance and medium resistance of the product.

[0032] 2. The anti-sticking, stain-resistant, lubricating and wear-resistant coating not only solves the yield of the rubber sealing ring of the washing machine, improves the service life of the sealing ring, and improves the quality, but also reduces the after-sales maintenance cost of the consumer. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] Examples 1-2 and Comparative Examples 1-5

[0035] An anti-sticking, stain-resistant, lubricating and wear-resistant coating includes the components shown in Table 1 by mass percentage.

[0036] Table 1 Composition of Examples and Comparative Examples

[0037]

[0038]

[0039] The self-dispersed urethane resin emulsion is a self-dispersed aliphatic polyester anionic polyurethane resin emulsion with a 60° glossiness of less than or equal to 0.5; the medium-soft polyurethane resin emulsion is an aliphatic polyester anionic polyurethane resin emulsion with an elongation of greater than or equal to 850% (elongation after the emulsion is formed into a film). The water-based chlorinated polypropylene has a chlorine content of 15%. The silicone dispersion water-based silicone emulsion is obtained by emulsifying polysiloxane powder with an average particle size of 240 nm, the high-silicon modified polyurethane emulsion is an organic-silicon modified aliphatic polyurethane emulsion, and the mass ratio of the organic-silicon chain is 70%. The modified intermediate silicone resin emulsion is a methoxy low-molecular-weight active silicone intermediate, and the number average molecular weight is 15000.

[0040] After the components are uniformly mixed, they are sprayed onto the surface of the EPDM substrate, and the baking temperature is 120°C for 20 minutes.

[0041] Performance test

[0042] Coating adhesion test: gauze is wrapped around a 50-gram weight and rubbed against the sprayed part for 40 times in succession, and whether the surface coating falls off is observed. This standard is a test standard provided by a washing machine manufacturer.

[0043] Temperature resistance test: 150°C for 96 hours, and whether the coating falls off and turns yellow is observed; 180°C for 96 hours, and whether the coating falls off and turns yellow is observed.

[0044] Stretch resistance test (elasticity): the product is stretched by 1.5 times, the coating is wiped with a fingernail, and whether the coating falls off is observed; in addition, the final test is performed, the adhesive strip is broken, and whether the coating falls off is observed.

[0045] Table 2: Performance test results of the examples and comparative examples

[0046]

[0047] As can be seen from Table 2, when the amount of chlorinated polypropylene is reduced, partial cracking occurs after the break test, the surface coating partially falls off in the adhesion test, and cracking and falling off of different degrees occur when the product is stretched by 1.5 times and broken, which indicates that the chlorinated polypropylene can improve the adhesion of the coating. When the high-silicon modified polyurethane emulsion is not added, the performance at 180°C is reduced. When the modified intermediate silicone resin is not added, the performance at 180°C is slightly reduced, and partial cracking and falling off occur after the break, which indicates that the high-silicon modified polyurethane emulsion and the modified intermediate silicone resin can synergistically improve the high-temperature resistance and elastic adhesion.

[0048] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An anti-blocking, stain repellent, lubricious, wear resistant coating for EPDM rubber, characterized in that, By mass percentage, the following components are included: Self-extinguishing polyurethane resin emulsion 12~22%; Medium-soft polyurethane resin emulsion 30~40%; Water-based chlorinated polypropylene resin emulsion 10~20%; Silicone dispersion water-based silicone emulsion 2~6%; PTFE dispersion emulsion 2~6%; Silicone-modified aliphatic polyurethane emulsion 2~8%; Modified intermediate silicone resin emulsion 1~5%; Isocyanate curing agent and / or γ-glycidyl ether oxypropyl trimethoxysilane 1~12%; Water 1~6%; Leveling agent 0.0~0.5%; Surfactant 0.0~1%; Thickening agent 0.0~0.8%; Co-solvent 0~18%; The modified intermediate silicone resin emulsion is a methoxy low molecular weight active silicone intermediate with a molecular weight of 10000~20000 and a solid content of 38~42%.

2. The anti-blocking, stain resistant, lubricious wear resistant coating of claim 1, wherein, The mass percentage of silicone chains in the silicone-modified aliphatic polyurethane emulsion is 65~75%, and the solid content of the silicone-modified aliphatic polyurethane emulsion is 25~35%.

3. The anti-galling, stain resistant, lubricious wear resistant coating of claim 1, wherein, The solid content of the water-based chlorinated polypropylene resin emulsion is 38~40%.

4. The anti-galling, stain resistant, lubricious wear resistant coating of claim 1, wherein, The solid content of the silicone dispersion water-based silicone emulsion is 75~85%; And / or, the solid content of the PTFE dispersion emulsion is 55~65%; And / or, the solid content of the self-extinguishing polyurethane resin emulsion is 30~33%, and the solid content of the medium-soft polyurethane resin emulsion is 28~32%. The self-extinguishing polyurethane resin and the medium-soft polyurethane resin are aliphatic polyester anionic polyurethane resins.

5. The anti-galling, stain resistant, lubricious wear resistant coating of claim 1, wherein, The co-solvent is ethanol; And / or, the leveling agent is an acrylate leveling agent; And / or, the surfactant is polyoxyethylene-8-octylphenyl ether; And / or, the thickening agent is one or more of hydroxypropyl methylcellulose, hydroxyethyl cellulose, and polyurethane associative thickening agent.

6. The anti-adhesive, stain resistant, lubricant resistant, wear resistant coating of any of claims 1-5, wherein, By mass percentage, the following components are included: Self-extinguishing polyurethane resin emulsion 15~20%; Medium-soft polyurethane resin emulsion 33~38%; Water-based chlorinated polypropylene resin emulsion 12~18%; Silicone dispersion water-based silicone emulsion 2~6%; PTFE dispersion emulsion 2~6%; Silicone-modified aliphatic polyurethane emulsion 2~8%; Modified intermediate silicone resin emulsion 1~5%; Isocyanate curing agent 2~4%; γ-glycidyl ether oxypropyl trimethoxysilane 3~6%; Water 2~6%; Leveling agent 0.1~0.4%; Surfactant 0.5~1%; Thickening agent 0.3~0.6%; Co-solvent 10~15%.

7. A method of making an anti-stiction, stain resistant, lubricious, wear resistant coating, characterized by, The anti-sticking, stain-resistant, lubricating, and wear-resistant coating is obtained by spraying the anti-sticking, stain-resistant, lubricating, and wear-resistant coating of any one of claims 1-6 onto the surface of the substrate and curing.

8. The method of making a stain and smear resistant, lubricant resistant, wear resistant coating of claim 7, wherein, The curing is baking at 110~130℃ for 15~30min, and the thickness of the coating is 5~20μm; And / or, the coating is diluted with water in a mass ratio of 1:(0.2~1), then preheated to 40~50℃ before being sprayed onto the surface of the substrate.

9. The anti-sticking, stain-resistant, lubricating, and wear-resistant coating prepared by the method of claim 7 or 8.

Images