Flexible wear-resistant fluorocarbon coating modified by NANO two-dimensional sheet, and preparation and use thereof

Abstract

Disclosed in the present invention are a flexible wear-resistant fluorocarbon coating modified by a nano two-dimensional sheet, and the preparation and use thereof. The flexible wear-resistant fluorocarbon coating modified by a nano two-dimensional sheet comprises paint and an isocyanate curing agent in a mass ratio of 7-10:1, wherein the paint comprises the following components in parts by mass: 15-25 parts of an organic solvent, 30-40 parts of a fluorocarbon resin, 5-10 parts of a castor oil polyol, 1-3 parts of a dispersing agent, 0.5-1 parts of a defoaming agent, 20-30 parts of titanium dioxide, 10-20 parts of barium sulfate, 0.1-1 parts of a nano two-dimensional sheet, 0.5-2 parts of a thickening agent, and 0.1-1 part of a leveling agent. In the present application, after the castor oil polyol and the fluorocarbon resin are mixed until dissolved, during the curing process, hydroxyl of the castor oil polyol can also be cured with the isocyanate to form a film, forming a polyurethane-fluorocarbon interpenetrating polymer network, thereby improving the flexibility of the fluorocarbon coating. In addition, the flexibility and wear resistance of a coating film can be improved by adding the nano two-dimensional sheet into the paint, and the flexible wear-resistant fluorocarbon coating modified by a nano two-dimensional sheet of the present application has good wear resistance and flexibility.

Description

A flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, its preparation and application Technical Field

[0001] This invention relates to the field of fluorocarbon coating technology, and in particular to a flexible wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, its preparation and application. Background Technology

[0002] Fluorocarbon coatings are coatings that use fluorocarbon resins as the main film-forming substance, also known as fluorocarbon paints. Among various coatings, fluorocarbon coatings, due to the high electronegativity of fluorine and the strong carbon-fluorine bond energy, possess excellent physical and mechanical properties, corrosion resistance, superior weather resistance, and maintenance-free self-cleaning properties, making them one of the coatings with the highest comprehensive performance. They are widely used in chemical plants, steel structures, bridges, aerospace, and other fields.

[0003] However, the application of this coating in the bridge industry, especially in concrete bridges, has been greatly limited. Concrete is highly susceptible to cracking under load, temperature changes, and shrinkage. Traditional fluorocarbon coatings have poor elasticity (elongation at break less than 50%), leading to coating cracking at crack sites. These cracks are directly exposed to a corrosive environment, a major cause of reduced load-bearing capacity and durability in concrete bridges. Furthermore, the tidal zones of cross-sea bridges are constantly subjected to erosion by seawater. Fluorocarbon coatings have poor abrasion resistance (1 kg, 1000 r, CS-10, film abrasion greater than 80 mg), and are quickly washed away in these areas, severely impacting the bridge's service life.

[0004] Therefore, it is essential to prepare a flexible wear-resistant fluorocarbon coating with high elongation at break and good wear resistance. Summary of the Invention

[0005] In view of this, this application provides a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating and its preparation and application, which is used to solve the problem of how to improve the elongation at break and wear resistance of fluorocarbon coatings.

[0006] To achieve the above technical objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, comprising a paint and an isocyanate curing agent in a mass ratio of 7-10:1; the paint comprises the following components in parts by mass: 15-25 parts organic solvent, 30-40 parts fluorocarbon resin, 5-10 parts castor oil polyol, 1-3 parts dispersant, 0.5-1 part defoamer, 20-30 parts titanium dioxide, 10-20 parts barium sulfate, 0.1-1 part nano-two-dimensional sheet, 0.5-2 parts thickener, and 0.1-1 part leveling agent.

[0008] Preferably, the nano-two-dimensional sheet comprises hexagonal boron nitride.

[0009] Preferably, the fluorocarbon resin includes tetrafluorocarbon resin.

[0010] Preferably, the organic solvent includes xylene and butyl acetate in a mass ratio of 3-4:1.

[0011] Preferably, the castor oil polyols include D290 (Vantrus).

[0012] Preferably, the dispersant includes one or more of the following: a controlled flocculation wetting dispersant, a solution of a low molecular weight unsaturated polycarboxylic acid polymer, and a polysiloxane copolymer; the defoamer includes an organosilicon defoamer; the thickener includes fumed silica; and the leveling agent includes an acrylic leveling agent.

[0013] Preferably, the isocyanate curing agent includes one or more of biuret-type curing agents and trimer-type curing agents.

[0014] Secondly, this application provides a method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, comprising the following steps:

[0015] In a mixed solution of fluorocarbon resin and castor oil polyol, dispersant, defoamer, titanium dioxide and barium sulfate are added and then ground. Then, nano-two-dimensional sheets, thickener and leveling agent are added and stirred evenly to obtain paint. The paint is then mixed with a curing agent to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0016] Preferably, the fineness of the material obtained after grinding is ≤30μm.

[0017] Thirdly, this application provides an application of a nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating in the field of bridges.

[0018] The beneficial effects of this application are as follows: After the castor oil polyol is mixed with the fluorocarbon resin, the hydroxyl groups of the castor oil polyol can also be cured with the isocyanate to form a film during the curing process, forming a polyurethane-fluorocarbon interpenetrating polymer network, thereby improving the flexibility of the fluorocarbon coating; at the same time, the addition of nano-two-dimensional sheets to the paint can improve the flexibility and wear resistance of the coating film. The nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating of this application has good wear resistance and flexibility, the elongation at break of the coating film can reach more than 100%, and the paint film wear is less than 50mg (1Kg, 1000r, CS-10). Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] This application provides a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, comprising a paint and an isocyanate curing agent in a mass ratio of 7-10:1; the paint comprises the following components in parts by mass: 15-25 parts organic solvent, 30-40 parts fluorocarbon resin, 5-10 parts castor oil polyol, 1-3 parts dispersant, 0.5-1 part defoamer, 20-30 parts titanium dioxide, 10-20 parts barium sulfate, 0.1-1 parts nano-two-dimensional sheets, 0.5-2 parts thickener, and 0.1-1 part leveling agent.

[0021] The nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating of this application has good wear resistance and flexibility. The reason is that castor oil polyol, as a long-chain polyol, has excellent flexibility and can be miscible with fluorocarbon resin. In this application, after the castor oil polyol is added to the fluorocarbon resin for mixing, during the curing process, the hydroxyl groups of the castor oil polyol can also be cured with isocyanate to form a film, forming a polyurethane-fluorocarbon interpenetrating polymer network, thereby improving the flexibility of the fluorocarbon coating. At the same time, adding nano-two-dimensional sheets to the paint can improve the flexibility and wear resistance of the coating film.

[0022] In some embodiments, the nano-two-dimensional sheet comprises hexagonal boron nitride.

[0023] In this embodiment, the nano-hexagonal boron nitride has a two-dimensional sheet structure similar to graphene. Compared with graphene, it has higher transparency and chemical inertness, soft texture, high mechanical strength and extremely low coefficient of friction. By adding nano-hexagonal boron nitride to the coating, this application can further improve the flexibility of the coating film and significantly improve its wear resistance.

[0024] In some embodiments, the fluorocarbon resin includes tetrafluorocarbon resin K570 (Daikin), which has better aging resistance than trifluorocarbon resin and can be used outdoors for a long time.

[0025] In some embodiments, the organic solvent comprises xylene and butyl acetate in a mass ratio of 3-4:1.

[0026] In some embodiments, castor oil polyols include D290 (Vantrus).

[0027] In some embodiments, the dispersant includes one or more of a controlled flocculation wetting dispersant, a solution of a low molecular weight unsaturated polycarboxylic acid polymer, and a polysiloxane copolymer; the defoamer includes an organosilicon defoamer; the thickener includes fumed silica; and the leveling agent includes an acrylic leveling agent.

[0028] In some embodiments, the dispersant is BYK 104S, the silicone defoamer is BYK 066N, and the acrylic leveling agent is AFCONA3777.

[0029] In some embodiments, the isocyanate curing agent includes one or more of biuret-type curing agents (N75, Covestro) and trimer-type curing agents (N3390, Covestro).

[0030] This application provides a method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, comprising the following steps:

[0031] In a mixed solution of fluorocarbon resin and castor oil polyol, dispersant, defoamer, titanium dioxide and barium sulfate are added and then ground. Then, nano-two-dimensional sheets, thickener and leveling agent are added and stirred evenly to obtain paint. The paint is then mixed with a curing agent to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0032] In some embodiments, the fineness of the material obtained after grinding is ≤30μm.

[0033] This application provides a method for modifying flexible, wear-resistant fluorocarbon coatings using nano-two-dimensional sheets in the field of bridge construction.

[0034] The following specific embodiments further illustrate this solution.

[0035] Example 1

[0036] A method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets includes the following steps:

[0037] Add 340g of tetrafluorocarbon resin and 60g of castor oil polyol D290 to a mixed solvent of 160g xylene and 50g butyl acetate. After mixing evenly, add 15g BYK 104S, 7g BYK 066N, 220g titanium dioxide and 130g precipitated barium sulfate. Then grind the material until the fineness is 30μm. Add 5g nano hexagonal boron nitride, 9g fumed silica and 4g AFCONA3777. Stir evenly to obtain the paint.

[0038] The paint and curing agent (N3390, Covestro) are mixed evenly at a mass ratio of 8:1 to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0039] Example 2

[0040] A method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets includes the following steps:

[0041] Add 340g of tetrafluorocarbon resin and 60g of castor oil polyol D290 to a mixed solvent of 160g xylene and 50g butyl acetate. After mixing evenly, add 15g BYK 104S, 7g BYK 066N, 220g titanium dioxide and 130g precipitated barium sulfate. Then grind the material until the fineness is 30μm. Add 5g nano hexagonal boron nitride, 9g fumed silica and 4g AFCONA3777. Stir evenly to obtain the paint.

[0042] Mix the paint and curing agent (N75, Covestro) at a mass ratio of 7:1 to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0043] Example 3

[0044] A method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets includes the following steps:

[0045] Add 340g of tetrafluorocarbon resin and 80g of castor oil polyol D290 to a mixed solvent of 160g xylene and 50g butyl acetate. After mixing evenly, add 15g BYK 104S, 7g BYK 066N, 220g titanium dioxide, and 110g precipitated barium sulfate. Then grind the material until the fineness is 30μm. Add 5g of nano hexagonal boron nitride, 9g of fumed silica, and 4g AFCONA3777. Stir evenly to obtain the paint.

[0046] The paint and curing agent (N3390, Covestro) are mixed evenly at a mass ratio of 8:1 to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0047] Example 4

[0048] A method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets includes the following steps:

[0049] Add 340g of tetrafluorocarbon resin and 60g of castor oil polyol D290 to a mixed solvent of 160g xylene and 50g butyl acetate. After mixing evenly, add 15g of BYK 104S, 7g of BYK 066N, 220g of titanium dioxide and 127g of precipitated barium sulfate. Then grind the material until the fineness is 30μm. Add 8g of nano hexagonal boron nitride, 9g of fumed silica and 4g of AFCONA3777. Stir evenly to obtain the paint.

[0050] The paint and curing agent (N3390, Covestro) are mixed evenly at a mass ratio of 8:1 to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0051] Example 5

[0052] A method for preparing a flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets includes the following steps:

[0053] Add 340g of tetrafluorocarbon resin and 80g of castor oil polyol D290 to a mixed solvent of 160g xylene and 50g butyl acetate. After mixing evenly, add 15g of BYK 104S, 7g of BYK 066N, 220g of titanium dioxide and 107g of precipitated barium sulfate. Then grind the material until the fineness is 30μm. Add 8g of nano hexagonal boron nitride, 9g of fumed silica and 4g of AFCONA3777. Stir evenly to obtain the paint.

[0054] The paint and curing agent (N3390, Covestro) are mixed evenly at a mass ratio of 8:1 to obtain a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0055] Comparative Example 1

[0056] A method for preparing a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating is the same as in Example 1, except that castor oil polyol and nano-hexagonal boron nitride are replaced with tetrafluorofluorocarbon resin.

[0057] Comparative Example 2

[0058] A method for preparing a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating is the same as in Example 1, except that nano-hexagonal boron nitride is replaced with tetrafluorofluorocarbon resin.

[0059] Comparative Example 3

[0060] A method for preparing a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating is the same as in Example 1, except that castor oil polyol is replaced with tetrafluorocarbon resin.

[0061] Comparative Example 4

[0062] A method for preparing a flexible wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets is the same as in Example 1, except that nano-hexagonal boron nitride is replaced with graphene.

[0063] Comparative Example 5

[0064] A method for preparing a nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating is the same as in Example 1, except that castor oil polyol is replaced with acrylic polyurethane resin.

[0065] Testing and Evaluation

[0066] After curing the coatings obtained in each embodiment and comparative example, the corresponding coatings were obtained. According to the test standards of GB / T 528-2009 "Determination of tensile properties of vulcanized rubber or thermoplastic rubber" and GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes by rotating rubber grinding wheel method", the elongation at break and film abrasion test (1Kg, 1000r, CS-10) of each coating were tested. The results are shown in Table 1.

[0067] Table 1 Test Results

[0068] As shown in Table 1, in Examples 1-5, the elongation at break of the modified flexible wear-resistant fluorocarbon coating film prepared by this invention can all reach over 100%, and the film wear is all less than 50 mg. The elongation at break of Example 1 is 108%, and the wear is 42 mg. Compared to Example 1, when only the curing agent was changed (Example 2), the crosslinking density of the biuret-type curing agent was lower than that of the trimer-type curing agent, resulting in improved film flexibility, reduced hardness, increased elongation at break to 115%, and increased abrasion to 46 mg. Compared to Example 1, when only the amount of castor oil polyol was increased (Example 3), the film flexibility and elongation at break were improved, but abrasion resistance decreased and abrasion increased. Compared to Example 1, when only the amount of hexagonal boron nitride was increased (Example 4), the film abrasion resistance was significantly improved, abrasion decreased, film flexibility was slightly improved, and elongation at break increased. Compared to Example 1, when both the amount of castor oil polyol and hexagonal boron nitride were increased (Example 5), the elongation at break of the film was significantly increased because the castor oil polyol (the higher the amount, the better the flexibility) and hexagonal boron nitride (the higher the amount, the slightly improved the flexibility) had the same effect on the film flexibility. Since castor oil polyols (the higher the dosage, the worse the wear resistance) and hexagonal boron nitride (the higher the dosage, the better the wear resistance) have opposite effects on the wear resistance of the coating, the wear resistance is slightly improved.

[0069] Compared to Example 1, when conventional fluorocarbon coatings were used (Comparative Example 1, without castor oil polyol and nano-hexagonal boron nitride), the elongation at break was significantly reduced and the wear was significantly increased due to the poor flexibility and abrasion resistance of the fluorocarbon resin itself. Compared to Example 1, when only castor oil polyol was used for modification (Comparative Example 2, without nano-hexagonal boron nitride), the addition of castor oil polyol significantly improved the flexibility of the coating film, but due to the poor abrasion resistance of castor oil polyol, the elongation at break of the coating film was slightly reduced, but the wear of the coating film increased significantly. Compared to Example 1, when only nano-hexagonal boron nitride was used for modification (Comparative Example 3, without castor oil polyol), the wear of the coating film was further reduced because nano-hexagonal boron nitride is soft and has high mechanical strength and extremely low coefficient of friction. However, due to its relatively small impact on the flexibility of the coating film (far less than the impact of castor oil polyol on the flexibility of the paint film), the elongation at break of the coating film is significantly reduced. Compared with Example 1, when only graphene is used to replace nano-hexagonal boron nitride (Comparative Example 4), the elongation at break of the coating film is slightly increased, and the wear of the coating film is significantly increased, because graphene has slightly higher flexibility than hexagonal boron nitride but lower hardness. In addition, since multilayer graphene is gray-black and the color becomes darker with the increase of the number of layers, its application in topcoat is limited to some extent (the topcoat cannot be tinted except for gray-black). Compared with Example 1, when only acrylic polyurethane resin is used to replace castor oil polyol (Comparative Example 5), the elongation at break of the coating film is significantly reduced, and the wear is significantly increased, because acrylic polyurethane resin has poor wear resistance and flexibility.

[0070] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A flexible, wear-resistant fluorocarbon coating modified with nano-two-dimensional sheets, characterized in that, The paint comprises a paint and an isocyanate curing agent in a mass ratio of 7-10:1; the paint comprises the following components in parts by mass: 15-25 parts organic solvent, 30-40 parts fluorocarbon resin, 5-10 parts castor oil polyol, 1-3 parts dispersant, 0.5-1 part defoamer, 20-30 parts titanium dioxide, 10-20 parts barium sulfate, 0.1-1 part nano-two-dimensional sheet, 0.5-2 parts thickener, and 0.1-1 part leveling agent.

2. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The nano-two-dimensional sheet includes hexagonal boron nitride.

3. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The fluorocarbon resin includes tetrafluorocarbon resin.

4. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The organic solvent comprises xylene and butyl acetate in a mass ratio of 3-4:

1.

5. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The castor oil polyol includes D290 purchased from Vantrus; the mass ratio of the castor oil polyol to hexagonal boron nitride is 5-20:

1.

6. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The dispersant includes one or more of the following: controlled flocculation wetting dispersant, low molecular weight unsaturated polycarboxylic acid polymer, and polysiloxane copolymer solution; the defoamer includes organosilicon defoamer; the thickener includes fumed silica; and the leveling agent includes acrylic leveling agent.

7. The nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 1, characterized in that, The isocyanate curing agent includes one or more of biuret-type curing agents and trimer-type curing agents.

8. A method for preparing a nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating as described in any one of claims 1-7, characterized in that, Includes the following steps: In a mixed solution of fluorocarbon resin and castor oil polyol, dispersant, defoamer, titanium dioxide and barium sulfate are added and then ground. Then, nano-two-dimensional sheets, thickener and leveling agent are added and stirred evenly to obtain paint. The paint and curing agent are mixed to obtain the nano-two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

9. The method for preparing the nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating according to claim 8, characterized in that, The fineness of the material obtained after grinding is ≤30μm.

10. The application of a nano-two-dimensional sheet-modified flexible wear-resistant fluorocarbon coating as described in any one of claims 1-7 in the field of bridges.

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