Nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating as well as preparation and application thereof

Abstract

The invention discloses a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating as well as preparation and application thereof. The nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating comprises paint and an isocyanate curing agent in a mass ratio of (7-10): 1, the paint vehicle comprises the following components in parts by mass: 15-25 parts of an organic solvent, 30-40 parts of fluorocarbon resin, 5-10 parts of castor oil polyol, 1-3 parts of a dispersing agent, 0.5-1 part of a defoaming agent, 20-30 parts of titanium dioxide, 10-20 parts of barium sulfate, 0.1-1 part of a nano two-dimensional sheet, 0.5-2 parts of a thickening agent and 0.1-1 part of a flatting agent; according to the invention, after the castor oil polyol is added into the fluorocarbon resin for mixing and dissolving, in the curing process, hydroxyl of the castor oil polyol can be cured with isocyanate to form a film, and a polyurethane-fluorocarbon interpenetrating polymer network is formed, so that the flexibility of the fluorocarbon coating is improved; meanwhile, the flexibility and wear resistance of a coating film can be improved by adding the nano two-dimensional sheet into the paint vehicle, and the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating disclosed by the invention is good in wear resistance and flexibility.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorocarbon coatings, and particularly to a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating and its preparation and application. Background Art

[0002] Fluorocarbon coating is a kind of coating with fluorocarbon resin as the main film-forming substance, also known as fluorocarbon paint. Among various coatings, fluorocarbon coating has excellent physical and mechanical properties, anti-corrosion properties, super weather resistance and maintenance-free self-cleaning properties due to the large electronegativity of fluorine element and strong carbon-fluorine bond energy. It is one of the coatings with the highest comprehensive performance and has been widely used in chemical plants, steel structures, bridges, aerospace and other fields.

[0003] However, the application of this coating in the field of bridges, especially in the field of concrete bridges, is greatly limited. Concrete is extremely prone to cracking under the action of load, temperature change, shrinkage, etc. Due to the poor elasticity of traditional fluorocarbon coatings (elongation at break is less than 50%), the coating at the crack is cracked, and the crack is directly exposed to the corrosive environment, which is the main reason for the reduction of the bearing capacity and durability of concrete bridges. In addition, the tidal zone of cross-sea bridges and the like is constantly scoured by seawater and the like. The wear resistance of fluorocarbon coatings is poor (1 Kg, 1000 r, CS-10, film abrasion is greater than 80 mg), and it is quickly washed away in this area, seriously affecting the service life of the bridge.

[0004] Therefore, it is very necessary 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, the present application provides a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating and its preparation and application, which are 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 purpose, the present application adopts the following technical solutions: In the first aspect, the present application provides a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, which includes a paint and an isocyanate curing agent with a mass ratio of 7-10:1; the paint includes the following components in parts by mass: 15-25 parts of organic solvent, 30-40 parts of fluorocarbon resin, 5-10 parts of castor oil polyol, 1-3 parts of dispersant, 0.5-1 part of defoamer, 20-30 parts of titanium dioxide, 10-20 parts of barium sulfate, 0.1-1 part of nano two-dimensional sheet, 0.5-2 parts of thickener, 0.1-1 part of leveling agent.

[0007] Preferably, the nano two-dimensional sheet includes hexagonal boron nitride.

[0008] Preferably, the fluorocarbon resin includes tetrafluoro fluorocarbon resin.

[0009] Preferably, the organic solvent includes xylene and butyl acetate with a mass ratio of 3 - 4:1.

[0010] Preferably, the castor oil polyol includes D290 (from Vertellus).

[0011] Preferably, 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 a silicone defoamer; the thickener includes fumed silica; the leveling agent includes an acrylic leveling agent.

[0012] Preferably, the isocyanate curing agent includes one or more of a biuret - type curing agent and a trimer - type curing agent.

[0013] In a second aspect, the present application provides a method for preparing a nano - two - dimensional sheet - modified flexible wear - resistant fluorocarbon coating, including the following steps: In a mixed solution of fluorocarbon resin and castor oil polyol, add a dispersant, a defoamer, titanium dioxide, and barium sulfate, then grind, and then add nano - two - dimensional sheets, a thickener, and a leveling agent, stir evenly to obtain a paint; mix the paint with a curing agent to obtain the nano - two - dimensional sheet - modified flexible wear - resistant fluorocarbon coating.

[0014] Preferably, the fineness of the material obtained after grinding is ≤30 μm.

[0015] In a third aspect, the present application provides an application of the nano - two - dimensional sheet - modified flexible wear - resistant fluorocarbon coating in the field of bridges.

[0016] The beneficial effects of the present application are as follows: After adding castor oil polyol to the fluorocarbon resin and mixing them, during the curing process, the hydroxyl groups of the castor oil polyol can also react 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. The nano - two - dimensional sheet - modified flexible wear - resistant fluorocarbon coating of the present application has good wear resistance and flexibility, the elongation at break of the coating film can reach more than 100%, and the film abrasion is less than 50 mg (1 Kg, 1000 r, CS - 10). Detailed Embodiments

[0017] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further elaborates on the present invention in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] The present application provides a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, which comprises a paint and an isocyanate curing agent with a mass ratio of 7-10:1; 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 castor oil polyol, 1-3 parts of a dispersant, 0.5-1 part of an antifoaming agent, 20-30 parts of titanium dioxide, 10-20 parts of barium sulfate, 0.1-1 part of nano two-dimensional sheet, 0.5-2 parts of a thickener, and 0.1-1 part of a leveling agent.

[0019] The nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating of the present 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 the fluorocarbon resin. After adding castor oil polyol to the fluorocarbon resin and miscible, during the curing process, the hydroxyl group of castor oil polyol can also react 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.

[0020] In some embodiments, the nano two-dimensional sheet comprises hexagonal boron nitride.

[0021] In this embodiment, nano hexagonal boron nitride has a two-dimensional sheet structure similar to that of graphene. Compared with graphene, it has higher transparency and chemical inertness, is soft in texture, and at the same time has high mechanical strength and extremely low friction coefficient. After adding nano hexagonal boron nitride to the coating in the present application, the flexibility of the coating film can be further improved and the wear resistance of the coating film can be significantly improved.

[0022] In some embodiments, the fluorocarbon resin comprises tetrafluoro fluorocarbon resin K570 (Daikin), and its weather resistance is better than that of trifluoro fluorocarbon resin, and it can be used outdoors for a long time.

[0023] In some embodiments, the organic solvent comprises xylene and butyl acetate with a mass ratio of 3-4:1.

[0024] In some embodiments, the castor oil polyol comprises D290 (Vantrue).

[0025] In some embodiments, the dispersant comprises 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 antifoaming agent comprises a silicone antifoaming agent; the thickener comprises fumed silica; the leveling agent comprises an acrylic leveling agent.

[0026] In some embodiments, the dispersant is BYK 104S, the silicone antifoaming agent is BYK 066N, and the acrylic leveling agent is AFCONA 3777.

[0027] In some embodiments, the isocyanate curing agent includes one or more of biuret curing agents (N75, Covestro) and trimer curing agents (N3390, Covestro).

[0028] The present application provides a method for preparing a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, comprising the following steps: In a mixed solution of fluorocarbon resin and castor oil polyol, a dispersant, an antifoaming agent, titanium dioxide, and barium sulfate are added and ground, and then nano two-dimensional sheets, a thickener, and a leveling agent are added. After stirring evenly, a paint is obtained; the paint is mixed with a curing agent to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0029] In some embodiments, the fineness of the material obtained after grinding is ≤ 30 μm.

[0030] The present application provides an application of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating in the field of bridges.

[0031] The following further illustrates the present solution through specific examples.

[0032] Example 1 A method for preparing a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, comprising the following steps: In a mixed solvent of 160 g of xylene and 50 g of butyl acetate, 340 g of tetrafluoro fluorocarbon resin and 60 g of castor oil polyol D290 are added. After mixing evenly, 15 g of BYK 104S, 7 g of BYK 066N, 220 g of titanium dioxide, and 130 g of precipitated barium sulfate are added, and then ground until the fineness of the material is 30 μm. Then, 5 g of nano hexagonal boron nitride, 9 g of fumed silica, and 4 g of AFCONA 3777 are added. After stirring evenly, a paint is obtained; The paint is mixed evenly with a curing agent (N3390, Covestro) according to a mass ratio of 8:1 to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating.

[0033] Example 2 A method for preparing a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, comprising the following steps: In a mixed solvent of 160 g of xylene and 50 g of butyl acetate, 340 g of tetrafluoro fluorocarbon resin and 60 g of castor oil polyol D290 are added. After mixing evenly, 15 g of BYK 104S, 7 g of BYK 066N, 220 g of titanium dioxide, and 130 g of precipitated barium sulfate are added, and then ground until the fineness of the material is 30 μm. Then, 5 g of nano hexagonal boron nitride, 9 g of fumed silica, and 4 g of AFCONA 3777 are added. After stirring evenly, a paint is obtained; Mix the paint and the curing agent (N75, Covestro) evenly at a mass ratio of 7:1 to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint.

[0034] Example 3 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint, comprising the following steps: Add 340 g of tetrafluoro fluorocarbon resin and 80 g of castor oil polyol D290 to a mixed solvent of 160 g of xylene and 50 g of butyl acetate. After mixing evenly, add 15 g of BYK 104S, 7 g of BYK 066N, 220 g of titanium dioxide, and 110 g of precipitated barium sulfate, and then grind until the fineness of the material is 30 μm. Then add 5 g of nano hexagonal boron nitride, 9 g of fumed silica, and 4 g of AFCONA 3777, and stir evenly to obtain the paint; Mix the paint and the curing agent (N3390, Covestro) evenly at a mass ratio of 8:1 to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint.

[0035] Example 4 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint, comprising the following steps: Add 340 g of tetrafluoro fluorocarbon resin and 60 g of castor oil polyol D290 to a mixed solvent of 160 g of xylene and 50 g of butyl acetate. After mixing evenly, add 15 g of BYK 104S, 7 g of BYK 066N, 220 g of titanium dioxide, and 127 g of precipitated barium sulfate, and then grind until the fineness of the material is 30 μm. Then add 8 g of nano hexagonal boron nitride, 9 g of fumed silica, and 4 g of AFCONA 3777, and stir evenly to obtain the paint; Mix the paint and the curing agent (N3390, Covestro) evenly at a mass ratio of 8:1 to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint.

[0036] Example 5 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint, comprising the following steps: Add 340 g of tetrafluoro fluorocarbon resin and 80 g of castor oil polyol D290 to a mixed solvent of 160 g of xylene and 50 g of butyl acetate. After mixing evenly, add 15 g of BYK 104S, 7 g of BYK 066N, 220 g of titanium dioxide, and 107 g of precipitated barium sulfate, and then grind until the fineness of the material is 30 μm. Then add 8 g of nano hexagonal boron nitride, 9 g of fumed silica, and 4 g of AFCONA 3777, and stir evenly to obtain the paint; Mix the paint and the curing agent (N3390, Covestro) evenly at a mass ratio of 8:1 to obtain the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint.

[0037] Comparative Example 1 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, with other contents being the same as those in Example 1, except that castor oil polyol and nano hexagonal boron nitride are replaced with tetrafluoro fluorocarbon resin.

[0038] Comparative Example 2 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, with other contents being the same as those in Example 1, except that nano hexagonal boron nitride is replaced with tetrafluoro fluorocarbon resin.

[0039] Comparative Example 3 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, with other contents being the same as those in Example 1, except that castor oil polyol is replaced with tetrafluoro fluorocarbon resin.

[0040] Comparative Example 4 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, with other contents being the same as those in Example 1, except that nano hexagonal boron nitride is replaced with graphene.

[0041] Comparative Example 5 A preparation method of a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, with other contents being the same as those in Example 1, except that castor oil polyol is replaced with acrylic polyurethane resin.

[0042] Testing and Evaluation The coatings corresponding to the coatings obtained from each example and comparative example after curing were tested for the elongation at break and film abrasion test (1 Kg, 1000 r, CS-10) of each coating 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 - Rotating Rubber Wheel Method", and the results are shown in Table 1.

[0043] Table 1 Test Results

[0044] As can be seen from Table 1, for Examples 1-5, the elongation at break of the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon paint film prepared by the present invention can all reach more than 100%, and the film abrasion is less than 50 mg. The elongation at break of Example 1 is 108%, and the abrasion is 42 mg. Compared with Example 1, when only the curing agent is replaced (Example 2), since the crosslinking density of the biuret type curing agent is lower than that of the trimer type curing agent, the flexibility of its paint film is improved, the hardness is reduced, the elongation at break of the paint film is increased to 115%, and the abrasion is increased to 46 mg; compared with Example 1, when only the dosage of castor oil polyol is increased (Example 3), the flexibility of the paint film is improved, the elongation at break of the paint film is increased, but the wear resistance is decreased and the abrasion is increased; compared with Example 1, when only the dosage of hexagonal boron nitride is increased (Example 4), the wear resistance of the paint film is significantly improved, the abrasion is reduced, the flexibility of the paint film is slightly improved, and the elongation at break is increased; compared with Example 1, when the dosages of both castor oil polyol and hexagonal boron nitride are increased (Example 5), since the effects of castor oil polyol (the greater the dosage, the better the flexibility) and hexagonal boron nitride (the greater the dosage, the slightly improved flexibility) on the flexibility of the paint film are the same, the elongation at break of the paint film is significantly increased. Since the effects of castor oil polyol (the greater the dosage, the worse the wear resistance) and hexagonal boron nitride (the greater the dosage, the better the wear resistance) on the wear resistance of the paint film are opposite, the wear resistance is slightly improved.

[0045] Compared with Example 1, when using conventional fluorocarbon coatings (Comparative Example 1, without castor oil polyol and nano-hexagonal boron nitride), due to the poor flexibility and wear resistance of the fluorocarbon resin itself, its elongation at break decreased significantly and the abrasion increased significantly; compared with Example 1, when only modified with castor oil polyol (Comparative Example 2, without nano-hexagonal boron nitride), the addition of castor oil polyol would significantly improve the flexibility of the coating film, but due to the poor wear resistance of castor oil polyol, the elongation at break of the coating film decreased slightly, but the abrasion of the coating film increased significantly; compared with Example 1, when only modified with nano-hexagonal boron nitride (Comparative Example 3, without castor oil polyol), due to the soft texture of nano-hexagonal boron nitride, and at the same time having characteristics such as high mechanical strength and extremely low friction coefficient, the abrasion of the coating film was further reduced. However, due to its small impact on the flexibility of the coating film (much smaller than the impact of castor oil polyol on the flexibility of the coating film), the elongation at break of the coating film decreased significantly; compared with Example 1, when only using graphene to replace nano-hexagonal boron nitride (Comparative Example 4), since the flexibility of graphene was slightly higher than that of hexagonal boron nitride, but the hardness was lower than that of hexagonal boron nitride, the elongation at break of the coating film increased slightly and the abrasion of the coating film increased significantly. In addition, since multi-layer graphene is grayish-black and the color becomes darker with the increase in the number of layers, to a certain extent, it limits its application in topcoats (except for grayish-black, the topcoat cannot be color-matched); compared with Example 1, when only replacing castor oil polyol with acrylic polyurethane resin (Comparative Example 5), due to the poor wear resistance and flexibility of acrylic polyurethane resin, the elongation at break of the coating film decreased significantly and the abrasion increased significantly.

[0046] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating, characterized in that: The invention comprises a paint and an isocyanate curing agent in a mass ratio of 7-10:1; the paint comprises the following components in mass parts: 15-25 parts of an organic solvent, 30-40 parts of a fluorocarbon resin, 5-10 parts of castor oil polyol, 1-3 parts of a dispersant, 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 thickener, and 0.1-1 parts of a 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 comprises 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 (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 a controlled flocculation wetting dispersant, a low molecular weight unsaturated polycarboxylic acid polymer and a polysiloxane copolymer solution; the defoamer includes an organic silicon defoamer; the thickener includes fumed silica; and the leveling agent includes an 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 a biuret curing agent and a trimer curing agent.

8. A method for preparing a nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating according to any one of claims 1 to 7, characterized in that: The following steps are involved: In a mixed solution of fluorocarbon resin and castor oil polyol, a dispersant, a defoamer, titanium dioxide, and barium sulfate are added and ground, and then a nano two-dimensional sheet, a thickener, and a leveling agent are added, and after being stirred evenly, a paint is obtained; The paint is mixed with a curing agent 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 the grinding is ≤30 μm.

10. Application of the nano two-dimensional sheet modified flexible wear-resistant fluorocarbon coating as claimed in any one of claims 1 to 7 in the field of bridges.

Images