A water-based two-component polyurethane coating and rubber sealing material and preparation method thereof

Abstract

The present invention provides a water-based two-component polyurethane coating and a rubber sealing material and a preparation method thereof, and relates to the technical field of protective coatings. The water-based two-component polyurethane coating of the present invention comprises component A and component B, wherein component A comprises a lubricating slurry, a water-based resin, a polytetrafluoroethylene emulsion and glass microbeads, and the lubricating slurry comprises a solid lubricating filler, a wetting dispersant, a defoaming agent, a thickener and water; and component B comprises an isocyanate curing agent, a film-forming aid and water. The present invention uses a water-based two-component polyurethane as a continuous phase, which ensures anti-adhesion while ensuring elastic properties equivalent to those of the base rubber; solid lubricating fillers are used as lubricants to obtain outstanding lubrication effects; and polytetrafluoroethylene emulsion and glass microbeads are added to achieve anti-adhesion effects. The polyurethane coating provided by the present invention can form an elastic anti-adhesion, anti-friction and anti-wear lubricating coating, has the dual effects of anti-adhesion and lubrication, and has outstanding application value in the field of rubber sealing.

Description

Technical Field

[0001] The present invention relates to the technical field of protective coatings, and in particular to a water-based two-component polyurethane coating and a rubber sealing material and a preparation method thereof. Background Art

[0002] Rubber, a highly elastic polymer with reversible deformation properties, is widely used as a sealing material in automobiles, construction machinery, electronic equipment, household items, and other fields. In dynamic sealing applications, rubber material, under load, comes into contact with the contact surface and experiences relative slippage, generating friction with the contact surface and causing wear. Furthermore, under the influence of contact materials and media such as metal, rubber material can age and become stuck to the metal. These conditions can ultimately lead to startup difficulties, seal failure, and other serious consequences, including accidents and irreparable losses. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a two-component polyurethane coating and a rubber sealing material and a preparation method thereof. The two-component polyurethane coating provided by the present invention is used for rubber surface modification and has outstanding friction reduction, anti-wear, lubrication and anti-adhesion effects.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a water-based two-component polyurethane coating, comprising component A and component B;

[0006] The component A comprises a lubricating slurry, an aqueous resin, a polytetrafluoroethylene emulsion and glass microspheres, wherein the aqueous resin comprises aqueous polyurethane and / or aqueous hydroxyl-functional polyacrylic acid, and the lubricating slurry comprises a solid lubricating filler, a wetting and dispersing agent, a defoaming agent, a thickener and water; the mass ratio of the lubricating slurry, the aqueous resin, the polytetrafluoroethylene emulsion and the glass microspheres is (2-10):(1-10):(0-2):(0-0.2), and the mass ratio of the solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and water is (5-20):(0.1-4.0):(0.1-2.0):(0-1.0):(40-100);

[0007] The component B comprises an isocyanate curing agent, a film-forming aid and water, wherein the mass ratio of the isocyanate curing agent, the film-forming aid and the water is (5-15): (0-5): (10-30);

[0008] The mass ratio of component A to component B is 1:(0.2-1.5).

[0009] Preferably, the lubricating filler includes one or more of graphite, graphite fluoride, silicon nitride, boron nitride and molybdenum disulfide.

[0010] Preferably, the thickener comprises one or more of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, ethyl hydroxyethyl cellulose and polyurethane thickener.

[0011] Preferably, the aqueous resin is a resin emulsion or a resin dispersion.

[0012] Preferably, the film-forming aid includes one or more of ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether, ethylene glycol butyl ether acetate, ethyl 3-ethoxypropionate and dodecyl alcohol ester.

[0013] The present invention provides a method for preparing the water-based two-component polyurethane coating described in the above technical solution, comprising the following steps:

[0014] The solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and water are mixed and ball-milled to obtain a lubricating slurry;

[0015] Mixing the lubricating slurry, water-based resin, polytetrafluoroethylene emulsion and glass microspheres to obtain component A;

[0016] The isocyanate curing agent, the film-forming aid and water are mixed to obtain component B.

[0017] Preferably, the ball milling time is 5 to 12 hours.

[0018] The present invention provides the use of the water-based two-component polyurethane coating described in the above technical solution or the water-based two-component polyurethane coating prepared by the preparation method described in the above technical solution in the preparation of rubber sealing materials.

[0019] The present invention also provides a rubber sealing material, comprising a rubber base and a lubricating coating applied to the surface of the rubber base, wherein the lubricating coating is formed by the water-based two-component polyurethane coating described in the above technical solution or the water-based two-component polyurethane coating prepared by the preparation method described in the above technical solution.

[0020] The present invention provides a method for preparing the rubber sealing material described in the above technical solution, comprising the following steps:

[0021] The component A and the component B are mixed, and the obtained water-based two-component polyurethane coating is applied to the surface of the rubber substrate. After curing, the rubber sealing material is obtained.

[0022] The present invention provides a water-based two-component polyurethane coating, comprising component A and component B, wherein component A comprises a lubricating slurry, a water-based resin, a polytetrafluoroethylene emulsion and glass microspheres, the water-based resin comprises water-based polyurethane and / or water-based hydroxyl functional polyacrylic acid, the lubricating slurry comprises a solid lubricating filler, a wetting dispersant, a defoamer, a thickener and water; the mass ratio of the lubricating slurry, the water-based resin, the polytetrafluoroethylene emulsion and the glass microspheres is (2-10): (1-10): (0-2): (0 ~0.2), the mass ratio of the lubricating filler, wetting dispersant, defoamer, thickener and water is (5-20):(0.1-4.0):(0.1-2.0):(0-1.0):(40-100); the component B includes an isocyanate curing agent, a film-forming aid and water, and the mass ratio of the isocyanate curing agent, the film-forming aid and water is (5-15):(0-5):(10-30); the mass ratio of the component A to the component B is 1:(0.2-1.5). Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention uses an elastic two-component waterborne polyurethane (WPU) as a base material, ensuring anti-adhesion effects while maintaining elastic properties comparable to those of the base rubber, and can well adapt to the elastic deformation of the rubber. Solid lubricating fillers are used as lubricants to achieve outstanding lubrication effects. Anti-adhesion effects are achieved by adding polytetrafluoroethylene emulsion and glass microbeads, which are chemically stable at high temperatures and have outstanding anti-adhesion effects. The waterborne two-component polyurethane coating provided by the present invention can form an elastic anti-adhesion, anti-friction and anti-wear lubricating coating, with dual anti-adhesion and lubrication effects, and has more outstanding application value in the field of rubber sealing.

[0024] The two-component polyurethane coating provided by the present invention is a water-based system, which is environmentally friendly and safe;

[0025] The two-component polyurethane coating provided by the present invention can be used to modify the surface of rubber by dipping, spraying, etc., is not restricted by shape and size, and has low equipment requirements; and has a low curing temperature (can be cured by air drying at room temperature or drying), and has wider applicability.

[0026] The results of the examples show that when the rubber surface is modified with the water-based two-component polyurethane coating provided by the present invention, the friction coefficient of the modified rubber surface is reduced from 1.11 to 0.12; the adhesion to steel is reduced from 18.4N to 0N and the adhesion to copper is reduced from 32.4N to 0N at 100°C and 1MPa pressure for 24 hours, and the wear reduction, anti-wear performance and anti-adhesion performance are greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1The following are optical microscopic photographs of the coating surfaces of the lubricating coating modified nitrile rubber obtained in Application Examples 1 to 5 and the nitrile rubber (blank) after being stretched 50%. Figure 1 From left to right, they correspond to Application Example 1, Application Example 2, Application Example 3, Application Example 4, Application Example 5, and Nitrile Rubber (blank);

[0028] Figure 2 The test results of the anti-friction and anti-wear properties of the lubricating coating modified nitrile rubber and nitrile rubber (blank) in Application Example 7 are as follows: Figure 2 (a) shows the friction coefficient and wear diagram of the lubricating coating and nitrile rubber (blank), and (b) shows the long wear diagram of the lubricating coating. DETAILED DESCRIPTION

[0029] The present invention provides a water-based two-component polyurethane coating, comprising component A and component B;

[0030] The component A comprises a lubricating slurry, an aqueous resin, a polytetrafluoroethylene emulsion and glass microspheres, wherein the aqueous resin comprises aqueous polyurethane and / or aqueous hydroxyl-functional polyacrylic acid, and the lubricating slurry comprises a solid lubricating filler, a wetting and dispersing agent, a defoaming agent, a thickener and water; the mass ratio of the lubricating slurry, the aqueous resin, the polytetrafluoroethylene emulsion and the glass microspheres is (2-10):(1-10):(0-2):(0-0.2), and the mass ratio of the solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and water is (5-20):(0.1-4.0):(0.1-2.0):(0-1.0):(40-100);

[0031] The component B comprises an isocyanate curing agent, a film-forming aid and water, wherein the mass ratio of the isocyanate curing agent, the film-forming aid and the water is (5-15): (0-5): (10-30);

[0032] The mass ratio of component A to component B is 1:(0.2-1.5).

[0033] In the present invention, unless otherwise specified, all raw materials involved are commercially available products well known in the art.

[0034] The present invention provides a water-based two-component polyurethane coating, comprising component A. In the present invention, component A comprises a lubricating slurry, a water-based resin, a polytetrafluoroethylene emulsion, and glass microspheres, wherein the mass ratio of the lubricating slurry, the water-based resin, the polytetrafluoroethylene emulsion, and the glass microspheres is (2-10):(1-10):(0-2):(0-0.2), preferably (3-4):(2-3):(0.6-1.5):(0-0.1). In an embodiment of the present invention, the mass ratio of the lubricating slurry, the water-based resin, the polytetrafluoroethylene emulsion, and the glass microspheres is 3:2:0:0, 4:2:0:0, 3:2:0.6:0, 3:2:0:0.04, or 3:2:0.6:0.04.

[0035] In the present invention, the lubricating slurry includes a solid lubricating filler, a wetting and dispersing agent, a defoaming agent, a thickener and water. The mass ratio of the solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and the water is (5-20): (0.1-4.0): (0.1-2.0): (0-1.0): (40-100), preferably (10-15): (1.0-2.0): (0.5-1.5): (0.01-0.5): (40-60), more preferably (10-12): (1.0-1.5): (0.5-1.0): (0.01-0.05): (40-50), and further preferably 10:1.2:1.0:0.04:40. In the present invention, the solid lubricating filler preferably includes one or more of graphite, graphite fluoride, silicon nitride, boron nitride, and molybdenum disulfide, more preferably graphite, silicon nitride, and molybdenum disulfide. The mass ratio of graphite, silicon nitride, and molybdenum disulfide is preferably 6:3:1, 3:6:1, 6:1:3, or 3:1:6. In the present invention, the particle size of the solid lubricating filler is preferably 0.5 to 5.0 μm. In the present invention, the wetting and dispersing agent preferably includes one or more of TEGO Dispers655, TEGO Dispers 735W, TEGO Dispers 740W, TEGO Dispers 750W, TEGO Dispers 755W, TEGO Dispers760W, ZetaSperse 2500, ZetaSperse 3100, ZetaSperse 3400, ZetaSperse3600, B 6090, DisperBYK-180, DisperBYK-190, DisperBYK-191, DisperBYK-23160, DisperBYK-2010, Triton CF-10, Triton X-405, Triton OT-75, Triton X-100, OROTAN 731A, SN5040, AdditolVXW 6208 / 60 and LCN 407. In the present invention, the defoaming agent preferably includes one or more of BYK-019, BYK-023, BYK-024, BYK-034, BYK 1780, TEGO FOAMEX 810, Tego Foamex 825, TEGOFOAMEX 920, TEGO FOAMEX 1488, TEGO Airex 904W, FoamStar 2410AC, FoamStar SI 2250 and Foamaster 328.In the present invention, the thickener preferably includes one or more of hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC), carboxymethyl cellulose (CMC), ethyl hydroxyethyl cellulose (EHEC) and polyurethane thickener.

[0036] In the present invention, the waterborne resin includes a waterborne polyurethane and / or a waterborne hydroxyl-functional polyacrylic acid, wherein the waterborne hydroxyl-functional polyacrylic acid reacts with an isocyanate curing agent to form a polyurethane; the waterborne resin is preferably a resin emulsion or a resin dispersion. In the present invention, the waterborne polyurethane preferably includes one or more of NeoRez R-600, NeoRez R-605, NeoRez R-961, NeoRez R-970, NeoRez R-974, NeoRez R-987, Alberdingk U2101, Alberdingk U6300, and Bayhydrol UH 2648 / 1, and the waterborne hydroxyl-functional polyacrylic acid preferably includes Bayhydrol A 2695 and / or Bayhydrol A 145.

[0037] In the present invention, the polytetrafluoroethylene emulsion is preferably one or more of DuPont TE 3859, DISP 30, DISP 33, and DISP40, and the solid content of the polytetrafluoroethylene emulsion is preferably 60 wt %.

[0038] In the present invention, the particle size of the glass microbeads is preferably one or more of 3M's S15, K15, IM30K, S60HS and IM16K. The particle size of the glass microbeads is preferably 10 to 100 μm, more preferably 10 to 40 μm.

[0039] The water-based two-component polyurethane coating provided by the present invention includes component B. In the present invention, the component B includes an isocyanate curing agent, a film-forming aid and water, and the mass ratio of the isocyanate curing agent, the film-forming aid and the water is (5-15):(0-5):(10-30), preferably (10-12):(2-3):(10-15), and more preferably (10-11):(2-2.5):(10-12.5). In the present invention, the isocyanate curing agent preferably includes one or more of Bayhydur 3100, Bayhydur 302, Bayhydur 304, Bayhydur 305, Bayhydur 307, Bayhydur 401-60, Bayhydur 401-70, Bayhydur XP 2451 / 1, Bayhydur XP 2487 / 1, Bayhydur XP 2547, Bayhydur XP 2655, Bayhydur XP 2700, HT-100, Aquolin 268 and Aquolin 270. In the present invention, the film-forming aid preferably includes one or more of ethylene glycol butyl ether (EB), propylene glycol methyl ether (PM), propylene glycol ethyl ether, propylene glycol butyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol monopropyl ether (DPnP), dipropylene glycol monobutyl ether (DPnB), tripropylene glycol n-butyl ether (TPnB), propylene glycol phenyl ether (PPH), ethylene glycol butyl ether acetate, ethyl 3-ethoxypropionate (EEP) and dodecyl alcohol ester (i.e., alcohol ester-12).

[0040] In the present invention, the mass ratio of component A to component B is 1:(0.2-1.5), preferably 1:(0.5-1), and more preferably 1:1.

[0041] The present invention utilizes a water-based two-component polyurethane as the continuous phase, graphite and molybdenum disulfide as solid lubricating fillers, and PTFE emulsion and glass microspheres as anti-adhesion fillers. This produces a polyurethane coating with outstanding wear-reducing, anti-wear, and anti-adhesion properties. The resulting coating also exhibits excellent flexibility and adapts well to the elastic deformation of rubber. Furthermore, the water-based two-component polyurethane coating provided by the present invention is a water-based system, making it environmentally friendly and safe.

[0042] The present invention provides a method for preparing the water-based two-component polyurethane coating described in the above technical solution, comprising the following steps:

[0043] The solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and water are mixed and ball-milled to obtain a lubricating slurry;

[0044] Mixing the lubricating slurry, water-based resin, polytetrafluoroethylene emulsion and glass microspheres to obtain component A;

[0045] The isocyanate curing agent, the film-forming aid and water are mixed to obtain component B.

[0046] The present invention mixes a solid lubricating filler, a wetting dispersant, a defoaming agent, a thickener and water (referred to as the first mixing) and performs ball milling to obtain a lubricating slurry. In the present invention, the method of the first mixing is preferably: adding the thickener to water under stirring conditions, then adding the wetting dispersant and the defoaming agent thereto, stirring until uniform, adding the solid lubricating filler, and stirring at a speed of 1000 to 2000 r / min until uniform. In the present invention, when the amount of the thickener added is 0, the addition of the thickener is omitted. In the present invention, the ball milling time is preferably 5 to 12 hours, more preferably 6 to 10 hours, and further preferably 8 hours. After the ball milling, the obtained slurry is preferably allowed to stand and filter in sequence to obtain the lubricating slurry; the standing time is preferably 10 to 24 hours.

[0047] After obtaining the lubricating slurry, the present invention mixes the lubricating slurry, an aqueous resin, a polytetrafluoroethylene emulsion (PTFE emulsion), and glass microspheres (referred to as the second mixing) to obtain component A. In the present invention, the second mixing method is preferably: mixing the lubricating slurry with the aqueous resin, stirring uniformly, and then adding the PTFE emulsion and glass microspheres thereto, stirring uniformly, to obtain component A. In the present invention, when the amount of the PTFE emulsion and glass microspheres added is 0, the addition of the PTFE emulsion and glass microspheres is omitted.

[0048] In the present invention, an isocyanate curing agent, a film-forming aid, and water are mixed (referred to as the third mixing) to obtain component B. In the present invention, the third mixing method is preferably as follows: the isocyanate curing agent and the film-forming aid are mixed (i.e., the curing agent is diluted with the film-forming aid), stirred uniformly, and then water is added thereto, and stirred at high speed to disperse uniformly to obtain component B.

[0049] The present invention provides the use of the water-based two-component polyurethane coating described in the above technical solution or the water-based two-component polyurethane coating prepared by the preparation method described in the above technical solution in the preparation of rubber sealing materials.

[0050] The present invention also provides a rubber sealing material, comprising a rubber base and a lubricating coating applied to the surface of the rubber base, wherein the lubricating coating is formed by the water-based two-component polyurethane coating described in the above technical solution or the water-based two-component polyurethane coating prepared by the preparation method described in the above technical solution.

[0051] In the present invention, the thickness of the lubricating coating is preferably 15 to 20 μm.

[0052] In the present invention, the water-based two-component polyurethane coating forms an elastic, anti-adhesive, and anti-friction lubricating coating on the rubber surface, simultaneously resolving the issues of insufficient wear resistance and susceptibility to adhesion in rubber sealing materials. Furthermore, the polyurethane emulsion or dispersion employed in the present invention is elastic, and when combined with a curing system of suitable strength, a coating is obtained that is compatible with the rubber substrate, thereby ensuring both anti-adhesive properties and elastic properties comparable to rubber.

[0053] The present invention provides a method for preparing the rubber sealing material described in the above technical solution, comprising the following steps:

[0054] The component A and the component B are mixed, and the obtained water-based two-component polyurethane coating is applied to the surface of the rubber substrate. After curing, the rubber sealing material is obtained.

[0055] In the present invention, the method for mixing component A and component B is preferably: adding component B to component A and stirring uniformly. In the present invention, water is preferably added to the waterborne two-component polyurethane coating to adjust the viscosity or workability of the coating before application; the mass ratio of the waterborne two-component polyurethane coating to water is preferably 2 to 5:1, more preferably 3 to 4:1.

[0056] In the present invention, the application method is preferably spray coating or dipping. Prior to application, the rubber surface is preferably cleaned. The present invention does not particularly require the surface cleaning method; methods well known to those skilled in the art may be employed. The present invention is not limited by the shape or size of the rubber and has low equipment requirements.

[0057] In the present invention, the curing is preferably air drying at room temperature, or heating and drying, or surface drying at room temperature followed by heating and drying; the heating and drying temperature is preferably 40-60° C., more preferably 50° C. The curing temperature in the present invention is low, and the adaptability is wider.

[0058] To further illustrate the present invention, the water-based two-component polyurethane coating and rubber sealing material and their preparation methods provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of protection of the present invention.

[0059] Examples 1 to 4 (Preparation of Lubricating Slurry)

[0060] The composition and dosage of the lubricating slurry are shown in Table 1, wherein the particle size of the solid lubricating filler is 0.5 to 5.0 μm.

[0061] The preparation method of the lubricating slurry is as follows:

[0062] The thickener is added to the water under stirring conditions, and then the wetting dispersant and defoaming agent are added. After stirring until uniform, the solid lubricating filler is added, and the mixture is stirred at 1500r / min until uniform. The mixture is transferred to a ball mill, and after 8 hours of grinding, the mixture is allowed to stand overnight and filtered to obtain the lubricating slurry for later use.

[0063] Table 1 Lubricating slurry formulations for Examples 1 to 4 (unit: g)

[0064]

[0065] Examples 5 to 10 (Preparation of Component A)

[0066] The composition and dosage of component A are shown in Table 2, wherein the particle size of the glass microspheres is 10 to 40 μm.

[0067] The preparation method of component A is as follows:

[0068] The lubricating slurry (prepared in Examples 1-2) and the aqueous polyurethane were mixed and stirred uniformly, and then the PTFE emulsion and the glass microbeads were added thereto and stirred uniformly to obtain component A.

[0069] Table 2 Formulation of Component A in Examples 5 to 10

[0070]

[0071] Examples 11-12 (Preparation of Component B, i.e., Curing Agent Emulsion)

[0072] The composition and dosage of component B are shown in Table 3. The preparation method of component B is as follows:

[0073] Dilute the curing agent with a film-forming aid, stir evenly, then add water and stir at high speed to disperse evenly to obtain component B.

[0074] Table 3 Formula of Component B of Examples 11 to 12

[0075]

[0076] Application Examples 1 to 6

[0077] Component A and component B were mixed uniformly under mechanical stirring according to the proportions in Table 4 to obtain a waterborne polyurethane coating.

[0078] Table 4 Waterborne polyurethane coating formula

[0079]

[0080] The coatings of Application Examples 1 to 6 were evenly sprayed onto the surface of nitrile rubber, with a dry film thickness of 15 to 20 μm. After drying at room temperature until the surface was dry, they were dried at 50°C for 24 hours. The adhesion, friction coefficient (dry grinding), and anti-adhesion properties of the coatings were tested. The test results are shown in Table 5. In Table 5, the friction coefficient test conditions are: the friction pair is a φ6mm steel ball, the load is 5N, 200 cycles, the frequency is 1Hz, and dry grinding; the adhesion strength test conditions are: GCr15 steel and copper with a surface finish of RA0.8 are in contact with rubber, and the rubber is left to stand at 100°C and a pressure of 1MPa for 24 hours. After cooling to room temperature, the tangential peel strength is measured.

[0081] Table 5 Test results of coating adhesion, anti-adhesion and lubrication performance

[0082]

[0083] Figure 1 The following are optical microscopic photographs of the coating surface of the modified nitrile rubber obtained in Application Examples 1 to 5 and the nitrile rubber (blank) after being stretched 50%. Figure 1 From left to right, they correspond to Application Example 1, Application Example 2, Application Example 3, Application Example 4, Application Example 5, and Nitrile Rubber (blank). Figure 1 It can be seen that, except for Application Example 2, the other anti-friction and anti-wear coatings can adapt to 50% deformation without cracking or peeling, and have good elastic properties; in Application Examples 4 and 5 where glass beads are added, the glass beads do not fall off after deformation, and the adhesion performance is good.

[0084] Application Example 7

[0085] Component A of Example 7 and component B of Example 12 were mixed uniformly under mechanical stirring in a mass ratio of 1:1, and the obtained water-based polyurethane coating was sprayed uniformly onto the surface of the nitrile rubber. The coating dry film thickness was 15 to 20 μm. After drying at room temperature until the surface was dry, it was dried at 50°C for 24 hours. The friction reduction and anti-wear properties of the coating were tested under the following test conditions: friction pair φ6mm steel ball, load 5N, frequency 1Hz, dry grinding. The test results are shown in Figure 2. Figure 2 As shown, Figure 2 The test results of the anti-friction and anti-wear properties of the lubricating coating modified nitrile rubber and nitrile rubber (blank) in Application Example 7 are as follows: Figure 2 (a) shows the friction coefficient and wear diagram of the lubricating coating and nitrile rubber (blank), and (b) shows the long wear diagram of the lubricating coating.

[0086] Figure 2The test results showed that after 100 friction cycles, the surface of the blank nitrile rubber showed obvious wear and tear, producing a large amount of wear debris. However, the nitrile rubber modified with the polyurethane lubricating coating showed excellent anti-friction and anti-wear properties, with a friction coefficient (μ) of 0.24. Even after 2,000 dry grinding cycles, no obvious wear marks were observed. Further investigation of the coating's anti-friction and anti-wear properties was conducted through 20,000 friction cycles. The average friction coefficient was 0.23, and the coating still maintained its good anti-friction and anti-wear effects after 20,000 friction cycles, with a friction coefficient of less than 0.25.

[0087] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A water-based two-component polyurethane coating for rubber sealing materials, characterized in that: It is composed of component A and component B; The component A is composed of a lubricating slurry, an aqueous resin, a polytetrafluoroethylene emulsion and glass microspheres, wherein the aqueous resin comprises aqueous polyurethane and / or aqueous hydroxyl-functional polyacrylic acid, and the lubricating slurry comprises a solid lubricating filler, a wetting and dispersing agent, a defoamer, a thickener and water; the mass ratio of the lubricating slurry, the aqueous resin, the polytetrafluoroethylene emulsion and the glass microspheres is (3-4):(2-3):(0.6-1.5):(0-0.1), and the mass ratio of the solid lubricating filler, the wetting and dispersing agent, the defoamer, the thickener and water is (5-20):(0.1-4.0):(0.1-2.0):(0-1.0):(40-100); The component B is composed of an isocyanate curing agent, a film-forming aid and water, and the mass ratio of the isocyanate curing agent, the film-forming aid and the water is (5-15): (0-5): (10-30); The mass ratio of component A to component B is 1:(0.2~1.5).

2. The water-based two-component polyurethane coating for rubber sealing materials according to claim 1, characterized in that: The solid lubricating filler includes one or more of graphite, graphite fluoride, silicon nitride, boron nitride and molybdenum disulfide.

3. The water-based two-component polyurethane coating for rubber sealing materials according to claim 1, characterized in that: The thickener includes one or more of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, ethyl hydroxyethyl cellulose and polyurethane thickener.

4. The water-based two-component polyurethane coating for rubber sealing materials according to claim 1, characterized in that: The water-based resin is a resin emulsion or a resin dispersion.

5. The water-based two-component polyurethane coating for rubber sealing materials according to claim 1, characterized in that: The film-forming aid includes one or more of ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether, ethylene glycol butyl ether acetate, ethyl 3-ethoxypropionate and dodecyl alcohol ester.

6. The method for preparing the water-based two-component polyurethane coating for rubber sealing materials according to any one of claims 1 to 5, characterized in that: The following steps are involved: The solid lubricating filler, the wetting and dispersing agent, the defoaming agent, the thickener and water are mixed and ball-milled to obtain a lubricating slurry; Mixing the lubricating slurry, water-based resin, polytetrafluoroethylene emulsion and glass microspheres to obtain component A; The isocyanate curing agent, the film-forming aid and water are mixed to obtain component B.

7. The preparation method according to claim 6, characterized in that The ball milling time is 5 to 12 hours.

8. A rubber sealing material, characterized in that: The invention comprises a rubber substrate and a lubricating coating applied to the surface of the rubber substrate, wherein the lubricating coating is formed by the water-based two-component polyurethane coating for rubber sealing materials according to any one of claims 1 to 5 or the water-based two-component polyurethane coating for rubber sealing materials prepared by the preparation method according to any one of claims 6 to 7.

9. The method for preparing the rubber sealing material according to claim 8, characterized in that: The following steps are involved: The component A and the component B are mixed, and the obtained water-based two-component polyurethane coating is applied to the surface of the rubber substrate. After curing, the rubber sealing material is obtained.

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