Organic-inorganic hybrid cross-linked polyurea coating, preparation method and application of organic-inorganic hybrid cross-linked polyurea coating in scratch resistance and oil stain resistance

Abstract

The invention discloses an organic-inorganic hybrid cross-linked polyurea coating, a preparation method and application of the organic-inorganic hybrid cross-linked polyurea coating to scratch resistance and oil stain resistance. The polyurea coating is obtained by crosslinking an isocyanate-containing component, an amino-containing compound and an inorganic nanoparticle. The polyurea coating generated by the reaction of the isocyanate group and the amino group has better oil stain resistance, acid and alkali resistance, ultraviolet radiation resistance and excellent adhesiveness on the surface of the membrane, and is not resistant to fingernail scratch due to lower hardness. The inorganic nanoparticles have the characteristics of small particle size, high hardness and the like, and the fingernail scratch resistance of the polyurea coating can be further enhanced after the inorganic nanoparticles are added. The organic-inorganic hybrid cross-linked polyurea coating prepared by the preparation method disclosed by the invention has excellent scratch resistance, oil stain resistance, ultraviolet radiation resistance and high temperature resistance.

Description

Technical Field

[0001] The invention relates to the field of materials, and in particular to an organic-inorganic hybrid cross-linked polyurea coating, a preparation method and an application thereof that is resistant to scratches and oil stains. Background Art

[0002] Polyurea is a high-performance elastomeric coating material known for its excellent physical and chemical properties, including wear resistance, corrosion resistance, water resistance and fast curing. Although traditional polyurea coatings have excellent physical and chemical properties, their surface hardness is relatively low and they are easily scratched by sharp objects or high friction. In addition, improper application conditions (such as low temperature, poor humidity control, etc.) or insufficient coating thickness will further reduce the scratch resistance of the coating. These problems limit the application of polyurea in some environments with high surface integrity requirements. Summary of the invention

[0003] The present invention aims to solve the problem that polyurea coating is prone to scratches and has insufficient scratch resistance, and designs an organic-inorganic hybrid cross-linked scratch-resistant and oil-resistant polyurea coating. The polyurea coating adopts isocyanate components and amino compounds to cross-link to obtain polyurea, and inorganic nanoparticles are used as fillers, and react with isocyanate to generate an organic-inorganic hybrid network structure, which effectively improves the scratch resistance of the polyurea coating. The polyurea coating prepared by the present invention has excellent adhesion performance, and has excellent properties of scratch resistance, oil resistance, ultraviolet radiation resistance, and acid and alkali resistance.

[0004] The preparation method provided by the present invention is specifically as follows: (1) Ultrasonic mixing of an amino compound and an isocyanate in a mass ratio of 1:1 to 4 to obtain a crosslinker emulsion; (2) dispersing the inorganic nanoparticles in a solvent and subjecting the solvent to ultrasonic treatment to obtain a suspension; (3) stirring and mixing the crosslinking agent emulsion obtained in step (1) and the suspension obtained in step (2) to be uniform, wherein the mass ratio of the amino compound to the inorganic nanoparticles is 1:0.5-2, preferably 1:1; (4) The mixed solution obtained in step (3) is evenly coated on the base film with a coater, and dried in an oven to obtain a thin film, thereby obtaining an organic-inorganic hybrid cross-linked polyurea coating.

[0005] Furthermore, the amino compound in step (1) comprises one of polyaspartic acid, 4,4'-diaminodiphenyl ether and diaminoformate.

[0006] Furthermore, the isocyanate in step (1) includes one of hexamethylene diisocyanate, toluene diisocyanate or methane diisocyanate.

[0007] Furthermore, the ultrasonic time in step (1) is 10 to 30 min.

[0008] Furthermore, the inorganic nanoparticles in step (2) include one of nano-silicon dioxide, aluminum oxide and carbon nanotubes. The isocyanate in step (1) can react with the inorganic nanoparticles in step (2) to form covalent bonds.

[0009] Furthermore, the solvent in step (2) includes one of water, ethanol or hydrofluoric acid.

[0010] The present invention also provides an organic-inorganic hybrid cross-linked polyurea coating prepared by the above preparation method.

[0011] The present invention also provides an application of the above-mentioned organic-inorganic hybrid cross-linked polyurea coating. The mixture prepared by the method is coated on the surface of a base film and dried. It has excellent adhesion on the film, is resistant to nail scratches, oil stains, and ultraviolet radiation, and has no obvious change when hot-pressed at a high temperature of 180°C for 10 seconds.

[0012] The beneficial effects of the present invention are: (1) A coating with both flexibility and strength is obtained by crosslinking organic polyurea with inorganic nanoparticles. The organic component and the inorganic component react to form covalent bonds, which makes the nanoparticles have good dispersion in the organic component and improves the mechanical properties of the organic-inorganic hybrid coating.

[0013] (2) The coating prepared by the present invention is simple and easy to prepare, and can improve the film's anti-ultraviolet aging performance, oil resistance and high temperature resistance while retaining the performance of the decorative film; (3) The polyurea coating of the present invention is a water-based coating, which is environmentally friendly and highly safe and can be firmly attached to the membrane surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a comparison diagram of the polyurea coating in Example 1 after adding soy sauce and vinegar (a) and after cleaning (b); Figure 2 is a nail scratch resistance graph of the polyurea coating in Example 2; Figure 3 The original PVC decorative film (a) and the polyurea coating with added UV shielding agent (b) in Example 3 were photographed after being tested in a UV aging box for 100 hours; Figure 4 These are pictures of polyurea coatings without and with inorganic nanoparticles after being scratched by fingernails. DETAILED DESCRIPTION

[0015] The following examples are used to further illustrate the present invention, and their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, all parts by weight and weight percentages are used below.

[0016] The raw materials used in the present invention, unless otherwise specified, are conventional commercially available products; the methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0017] The embodiments of the present invention are further described below with reference to a plurality of embodiments.

[0018] It should be clear that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0020] Example 1 (1) Weigh 1.0 g of polyaspartic acid and 3.0 g of hexamethylene diisocyanate, and continuously ultrasonicate for 10 min at room temperature to obtain an emulsion as an organic crosslinking agent; (2) Weigh 1.0 g of fumed silica and 25 mL of ethanol to prepare an inorganic nanoparticle suspension, stir at room temperature, and then use an ultrasonic crushing instrument to evenly disperse the inorganic nanoparticles in the ethanol to obtain an inorganic nanoparticle suspension as a filler; (3) Weigh 4 g of the mixed liquid containing isocyanate components and amino compounds in (1) and 1.0 g of the inorganic nanoparticle suspension and stir and mix them at room temperature. After stirring and mixing, use a coater to evenly apply them on the PVC base film and dry them in an oven at 110°C for 2 h to obtain a thin film, which is a cross-linked polyurea coating. Add soy sauce and vinegar to the polyurea coating and wash it off after 16 h. Figure 1 As shown, it has good oil resistance.

[0021] Example 2 (1) Weigh 1.0 g of diurethane and 2.0 g of toluene diisocyanate, and continue ultrasonication at room temperature for 30 min to obtain an emulsion as an organic crosslinking agent; (2) The experimental apparatus and operation were the same as those in Example 1, except that 1.0 g of fumed silica in step (2) was replaced by 0.5 g of aluminum oxide, and 25 mL of ethanol was replaced by 25 mL of water.

[0022] (3) The experimental device and operation are the same as in Example 1. The results of the scratch resistance test using fingernails on the laboratory table are as follows: Figure 2 As shown, it has good scratch resistance.

[0023] Example 3 (1) The experimental apparatus and operation were the same as those in Example 1. In step (1), 1.0 g of polyaspartic acid was replaced by 1.0 g of 4,4'-diaminodiphenyl ether, and 3.0 g of hexamethylene diisocyanate was replaced by 2.0 g of methane diisocyanate.

[0024] (2) The experimental apparatus and operation were the same as those in Example 1, except that in step (2), 1.0 g of fumed silica was replaced by 2 g of carbon nanotubes, and 25 mL of ethanol was replaced by 25 mL of hydrofluoric acid.

[0025] (3) The experimental device and operation were the same as those in Example 1, except that 0.0029 g of ultraviolet shielding agent was added in step (3). The polyurea coating prepared in this example was scraped onto a PVC decorative film and placed in a UV aging chamber for 100 h. Figure 3 After adding UV shielding agent, the polyurea coating has obvious anti-UV aging effect.

[0026] Example 4 (1) The experimental apparatus and operation were the same as those in Example 1. In step (1), 1.0 g of polyaspartic acid was replaced by 1.0 g of diurethane, and 3.0 g of hexamethylene diisocyanate was replaced by 4 g of methane diisocyanate.

[0027] (2) The experimental apparatus and operation were the same as those in Example 1, except that in step (2), 1.0 g of fumed silica was replaced with 1.0 g of silica.

[0028] (3) The experimental device and operation are the same as those in Example 1. In step (3), sample a is not added with carbon nanotube suspension, and sample b is a polyurea coating with carbon nanotubes added. The polyurea coating prepared in this example is coated on the surface of the PVC base film and compared with sample b. The results of scratching samples a and b with fingernails on the experimental table are shown in Figure 1. Figure 4 As shown, the anti-scratch effect of sample b is significantly better than that of sample a.

[0029] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the protection scope of the present invention.

Claims

1. A method for preparing an organic-inorganic hybrid cross-linked polyurea coating, characterized in that: The specific steps are as follows: (1) Ultrasonic mixing of an amino compound and an isocyanate in a mass ratio of 1:1 to 4 to obtain a crosslinker emulsion; (2) dispersing the inorganic nanoparticles in a solvent and subjecting the solvent to ultrasonic treatment to obtain a suspension; (3) stirring and mixing the crosslinking agent emulsion obtained in step (1) and the suspension obtained in step (2) to be uniform, wherein the mass ratio of the amino compound to the inorganic nanoparticles is 1:0.5-2; (4) The mixed solution obtained in step (3) is coated on the base film by knife coating and dried in an oven to obtain an organic-inorganic hybrid cross-linked polyurea coating on the base film.

2. The preparation method according to claim 1, characterized in that: The amino compound in step (1) comprises one of polyaspartic acid, 4,4'-diaminodiphenyl ether and diaminoformate.

3. The preparation method according to claim 1, characterized in that: The isocyanate in step (1) includes one of hexamethylene diisocyanate, toluene diisocyanate or methane diisocyanate.

4. The preparation method according to claim 1, characterized in that: The isocyanate in step (1) can react with the inorganic nanoparticles in step (2) to form a covalent bond.

5. The preparation method according to claim 1, characterized in that: The inorganic nanoparticles in step (2) include one of nano silicon dioxide, aluminum oxide and carbon nanotubes.

6. The preparation method according to claim 1, characterized in that: The solvent in step (2) includes one of water, ethanol and hydrofluoric acid.

7. The organic-inorganic hybrid cross-linked polyurea coating prepared by the preparation method according to claims 1 to 6.

8. Use of the organic-inorganic hybrid cross-linked polyurea coating as claimed in claim 7 as a base film scratch-resistant and oil-resistant coating.

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