Super-hydrophobic high-solid-content coating and preparation method thereof

Abstract

The invention discloses a super-hydrophobic high-solid-content coating and a preparation method thereof. The super-hydrophobic high-solid-content coating comprises the following components in parts by mass: 38-42 parts of polyaspartic acid ester; 41-47 parts of an isocyanate curing agent; and 11-21 parts of hydrophobic modified inorganic nanoparticles. The preparation method disclosed by the invention has the characteristics of simplicity and easiness in implementation, and the prepared super-hydrophobic high-solid-content coating has very good hydrophobic performance and relatively high comprehensive paint film performance.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and more specifically to a super-hydrophobic high-solid content coating and a preparation method thereof. Background Art

[0002] Asparagus polyurea is a new type of aliphatic, slow-reacting, high-performance coating material in the polyurea industry. It is called the third-generation polyurea. Compared with other resin coatings, it has more convenient construction methods, better adhesion, and more energy-saving and environmentally friendly properties. Asparagus polyurea is a high-solid chemical material with extremely low VOCs emissions, low odor, environmental friendliness, safety and non-toxicity. It is an ideal new environmentally friendly material. It is currently widely used in the fields of anti-corrosion, flooring, adhesives, structural materials, etc. It has excellent weather resistance, UV resistance, aging resistance, acid and alkali resistance, etc. that far exceed other materials. It will not turn yellow, crack or powder after years of direct outdoor exposure.

[0003] In recent years, the anti-fouling and self-cleaning properties of super-hydrophobic materials have received widespread attention in the fields of ships, outdoor buildings, etc. However, poor wear resistance and weather resistance have always been important issues that need to be addressed. Therefore, if polyurea resin with excellent outdoor performance is combined with super-hydrophobic materials, it can not only improve the poor weather resistance of super-hydrophobic coatings, but also provide a new direction for the application expansion of high-solid coatings. Summary of the invention

[0004] In view of the defects existing in the prior art, the purpose of the present invention is to provide a super hydrophobic high solid content coating and a preparation method thereof, which is simple and easy to implement. The prepared super hydrophobic high solid content coating has good hydrophobic performance and high comprehensive paint film performance.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a super hydrophobic high solid content coating, the components of which are calculated by mass fraction as follows:

[0007] 38-42 parts of polyaspartic acid;

[0008] 41-47 parts of isocyanate curing agent;

[0009] 11 to 21 parts of hydrophobically modified inorganic nanoparticles.

[0010] Preferably, the isocyanate curing agent is isocyanate HDI trimer.

[0011] Preferably, the hydrophobically modified inorganic nanoparticles are obtained by modifying inorganic nanoparticles with a silane coupling agent containing an amino functional group and a fluorine-containing silane.

[0012] Preferably, the silane coupling agent is selected from one of 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane and N-2-aminoethyl-3-aminopropylmethyldimethoxysilane;

[0013] The fluorine-containing silane is selected from one of heptadecafluorodecyltrimethoxysilane and perfluorooctyltrichlorosilane;

[0014] The inorganic nanoparticles are one of nano silicon dioxide, nano calcium sulfate, nano zinc oxide or nano titanium oxide.

[0015] The second aspect of the present invention provides a method for preparing a super-hydrophobic high-solid coating as described in the first aspect of the present invention, wherein polyaspartic acid ester and hydrophobically modified inorganic nanoparticles are mixed and fully stirred, and then an isocyanate curing agent is added and continued to be stirred evenly to obtain a super-hydrophobic high-solid coating.

[0016] Preferably, the preparation process of the hydrophobically modified inorganic nanoparticles is as follows:

[0017] S1, dissolving an amino-containing silane coupling agent in a solution of ethanol and deionized water, adjusting the pH to acidic, and magnetically stirring at room temperature to obtain a mixed solution; then adding inorganic nanoparticles to the mixed solution, mechanically stirring under heating conditions to fully react, collecting the reaction product by suction filtration or centrifugation, and vacuum drying the reaction product to obtain amino-modified nanoparticles;

[0018] S2, dispersing the amino-modified nanoparticles in ethanol, adding fluorinated silane, and stirring fully at room temperature, then collecting the reaction product by suction filtration or centrifugation, and vacuum drying to obtain hydrophobically modified inorganic nanoparticles.

[0019] Preferably, in step S1:

[0020] In the mixed solution, the mass ratio of the amino-containing silane coupling agent to ethanol and deionized water is 1:3.6-5.0:0.4-4.5;

[0021] The mass ratio of the inorganic nanoparticles to the mixed solution is 1:10 to 50;

[0022] The size of the inorganic nanoparticles is 10-100 nm.

[0023] Preferably, in step S1:

[0024] When adjusting the pH to acidic, a weak acid is used to adjust the pH of the solution to 5.5-6.5;

[0025] The magnetic stirring mixing time is 0.5 to 4 hours;

[0026] When the inorganic nanoparticles are added to the mixed solution, the heating temperature is 80 to 90° C. and the mechanical stirring time is 4 to 24 hours;

[0027] During the vacuum drying, the drying temperature is 50-60° C. and the drying time is 1-12 hours.

[0028] Preferably, in step S2, the mass ratio of the amino-modified nanoparticles, the fluorinated silane, and the ethanol is 1:0.2-0.6:10-100.

[0029] Preferably, in the vacuum drying process of step S2, the drying temperature is 60-70° C. and the drying time is 1-12 hours.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention adopts high-solid polyurea resin as the polymer component of the coating. The high-solid coating can not only meet environmental protection requirements, but also has excellent weather resistance, UV resistance, aging resistance, acid and alkali resistance and other properties far exceeding other materials;

[0032] 2. The hydrophobically modified inorganic nanoparticles of the present invention have amino groups that are covalently bonded to the curing agent, which greatly improves the mechanical properties of the super-hydrophobic coating;

[0033] 3. The present invention is simple and easy to implement. The prepared super-hydrophobic high-solid coating has excellent hydrophobic properties and high comprehensive paint film performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of a method for preparing a super-hydrophobic high-solid coating;

[0035] Figure 2 This is a static contact angle observation diagram of a high-solid super-hydrophobic coating sample prepared from the super-hydrophobic coating of Example 1 of the present invention. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0037] The super hydrophobic high solid content coating of the present invention has the following components by mass fraction:

[0038] 38-42 parts of polyaspartic acid;

[0039] 41-47 parts of isocyanate curing agent;

[0040] 11 to 21 parts of hydrophobically modified inorganic nanoparticles.

[0041] The super hydrophobic high solid content coating of the present invention is a polyurea resin of AB two components, wherein component A is polyaspartic acid ester and component B is an isocyanate curing agent (i.e. isocyanate HDI trimer).

[0042] The hydrophobically modified inorganic nanoparticles are obtained by modifying the inorganic nanoparticles with a silane coupling agent containing an amino functional group and a fluorine-containing silane. The silane coupling agent is selected from one of 3-aminopropyl triethoxysilane, N-2-aminoethyl-3-aminopropyl trimethoxysilane or N-2-aminoethyl-3-aminopropyl methyl dimethoxysilane; the fluorine-containing silane is selected from one of heptadecafluorodecyl trimethoxysilane and perfluorooctyl trichlorosilane; and the inorganic nanoparticles are selected from one of nano silicon dioxide, nano calcium sulfate, nano zinc oxide or nano titanium oxide.

[0043] Combination Figure 1 As shown, the present invention also provides a method for preparing the above-mentioned super-hydrophobic high-solid coating, which comprises mixing polyaspartic acid ester and hydrophobically modified inorganic nanoparticles and stirring them sufficiently, then adding isocyanate curing agent and continuing to stir evenly to obtain the super-hydrophobic high-solid coating.

[0044] The preparation process of hydrophobically modified inorganic nanoparticles is as follows:

[0045] S1, dissolving an amino-containing silane coupling agent in a solution of ethanol and deionized water, adjusting the pH to acidic, and magnetically stirring at room temperature to obtain a mixed solution, then adding inorganic nanoparticles and the mixed solution to ethanol, mechanically stirring under heating conditions to obtain uniform mixture, collecting the reaction product by suction filtration or centrifugation, and vacuum drying the reaction product to obtain amino-modified nanoparticles;

[0046] In this step, a silane coupling agent containing amino groups, ethanol and deionized water are prepared in a mass ratio of 1:3.6-5.0:0.4-4.5. After the silane coupling agent containing amino groups is dissolved in a solution of ethanol and deionized water, a weak acid is used to adjust the pH of the solution to 5.5-6.0, and a mixed solution is obtained after magnetic stirring at room temperature for 0.5-4 hours. Then, inorganic nanoparticles are added to the mixed solution, and mechanical stirring is performed to fully react under heating conditions of 60-70° C. The mechanical stirring time is 4-24 hours. Then, the reaction product is collected by suction filtration or centrifugation, and the reaction product is vacuum dried at a drying temperature of 50-60° C. for 1-12 hours to finally obtain amino-modified nanoparticles. The mass ratio of the inorganic nanoparticles to the mixed solution is 1:10-50, and the size of the inorganic nanoparticles is 10-100 nm.

[0047] S2, dispersing the amino-modified nanoparticles in ethanol, adding fluorinated silane, and stirring fully at room temperature, then collecting the reaction product by suction filtration or centrifugation, and vacuum drying to obtain hydrophobically modified inorganic nanoparticles.

[0048] In this step, the amino-modified nanoparticles prepared in S1 are dispersed in ethanol, and then fluorinated silane is added and stirred at room temperature, wherein the mass ratio of amino-modified nanoparticles, fluorinated silane, and ethanol is 1:0.2-0.6:10-100. The reaction product is then collected by suction filtration or centrifugation, and the reaction product is vacuum dried at a drying temperature of 60-70°C for 1-12 hours to obtain hydrophobically modified inorganic nanoparticles.

[0049] After the super hydrophobic high solid content coating prepared by the present invention is applied to a substrate, a high solid content super hydrophobic coating is obtained, and the water contact angle of the coating is ≥130° (for example, the water contact angle can be 130° to 145°).

[0050] Example 1

[0051] A method for preparing a super hydrophobic high solid content coating, the specific process is as follows:

[0052] (1) Preparation of hydrophobically modified silica of component C

[0053] The specific process of preparing the C component hydrophobically modified silica is as follows: dissolve aminopropyltriethoxysilane (APTES) in ethanol and deionized water, adjust the pH to 5.5 with weak acid, mix APTES, ethanol and deionized water in a mass ratio of 1:3.6:0.4, and magnetically stir at room temperature for 1 hour to obtain a mixed solution, then add nano-silica with a particle size of about 50nm to the mixed solution, mechanically stir at 70°C for 8 hours, collect the reaction product by suction filtration or centrifugation, and vacuum dry the reaction product at 60°C for 12 hours to obtain amino-modified silica. Disperse the amino-modified silica in ethanol, then add perfluorooctyltrichlorosilane (PFOTS), stir thoroughly at room temperature, the mass ratio of amino-modified silica, PFOTS and ethanol is 1:0.2:10, then collect the reaction product by suction filtration or centrifugation, and vacuum dry at 60°C for 8 hours to obtain hydrophobically modified silica.

[0054] In the above process, nano-silica is grafted with amino functional groups by reacting with APTES, and the surface hydroxyl groups are not completely reacted. Then the hydroxyl groups are reacted with PFOTS to graft hydrophobic groups to generate hydrophobically modified silica particles with surface hydrophobic groups and amino groups. The modification process is as follows:

[0055]

[0056] (2) Preparation of super-hydrophobic high-solid coatings and high-solid super-hydrophobic coatings

[0057] Select component A: polyaspartic acid ester, 38 parts; select component B: isocyanate curing agent HDI trimer, 41 parts; component C: hydrophobically modified silica 11 parts.

[0058] The polyaspartic acid resin of component A and the hydrophobically modified inorganic nanoparticles of component C are mixed and stirred thoroughly, and then the isocyanate curing agent of component B is added and stirred evenly to obtain a super hydrophobic high solid content coating. The reaction mechanism of component B and component A is as follows:

[0059]

[0060] The super-hydrophobic high-solid coating is immediately brushed or scraped onto the substrate, and a high-solid super-hydrophobic coating can be obtained after drying. Figure 2 From the static contact angle observation diagram of the high solid content super hydrophobic coating sample shown, it can be seen that the water contact angle of the high solid content super hydrophobic coating is 132°, which shows that the coating has good hydrophobic properties.

[0061] Example 2

[0062] A method for preparing a super hydrophobic high solid content coating, the specific process is as follows:

[0063] (1) Preparation of hydrophobically modified zinc oxide of component C

[0064] The specific process for preparing the hydrophobically modified zinc oxide of component C is as follows: N-2-aminoethyl-3-aminopropyltrimethoxysilane is dissolved in ethanol and deionized water, the pH is adjusted to 6.0 with a weak acid, N-2-aminoethyl-3-aminopropyltrimethoxysilane, ethanol and deionized water are mixed in a mass ratio of 1:4:1, and magnetically stirred at room temperature for 1.2 hours to obtain a mixed solution, and then nano zinc oxide with a particle size of about 80 nm is added to the mixed solution. After mechanical stirring at 60°C for 24 hours, the reaction product is collected by filtration or centrifugation, and the reaction product is vacuum dried at 55°C for 10 hours to obtain amino-modified zinc oxide. The amino-modified zinc oxide is dispersed in ethanol, and then heptadecafluorodecyltrimethoxysilane is added, and the mixture is fully stirred at room temperature. The amino-modified zinc oxide, heptadecafluorodecyltrimethoxysilane and ethanol are mixed in a mass ratio of 1:0.5:20. The reaction product is then collected by filtration or centrifugation, and dried at 65°C for 6 hours to obtain hydrophobic modified zinc oxide.

[0065] In the above process, nano zinc oxide is reacted with N-2-aminoethyl-3-aminopropyltrimethoxysilane to graft amino functional groups, and the surface hydroxyl groups are not completely reacted. The hydroxyl groups are then reacted with heptadecafluorodecyltrimethoxysilane to graft hydrophobic groups to generate hydrophobic modified zinc oxide particles with surface hydrophobic groups and amino groups.

[0066] (2) Preparation of super-hydrophobic high-solid coatings and high-solid super-hydrophobic coatings

[0067] Select component A: polyaspartic acid ester, 40 parts; select component B: isocyanate curing agent HDI trimer, 45 parts; component C: hydrophobically modified zinc oxide 15 parts.

[0068] The polyaspartic acid resin of component A and the hydrophobically modified zinc oxide of component C are mixed and stirred thoroughly, and then the isocyanate curing agent of component B is added and stirred evenly to obtain a super hydrophobic high solid content coating;

[0069] The super-hydrophobic high-solid coating is immediately brushed or scraped onto the substrate, and a high-solid super-hydrophobic coating is obtained after drying. The hydrophobic performance of the coating is tested, and its water contact angle is 138°, which shows that its hydrophobic performance is good.

[0070] Example 3

[0071] A method for preparing a super hydrophobic high solid content coating, the specific process is as follows:

[0072] (1) Preparation of hydrophobically modified titanium oxide component C

[0073] The specific process for preparing the C component hydrophobically modified titanium oxide is as follows: N-2-aminoethyl-3-aminopropylmethyldimethoxysilane is dissolved in ethanol and deionized water, the pH is adjusted to 6.0 with a weak acid, N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, ethanol and deionized water are mixed in a mass ratio of 1:5:4.5, and magnetically stirred at room temperature for 1.5 hours to obtain a mixed solution, and then nano-titanium oxide with a particle size of about 100 nm is added to the mixed solution. After mechanical stirring at 65°C for 18 hours, the reaction product is collected by filtration or centrifugation, and the reaction product is vacuum dried at 55°C for 6 hours to obtain amino-modified titanium oxide. The amino-modified titanium oxide is dispersed in ethanol, and then perfluorooctyltrichlorosilane is added and fully stirred at room temperature. The mass ratio of amino-modified titanium oxide, perfluorooctyltrichlorosilane and ethanol is 1:0.6:80. The reaction product is then collected by filtration or centrifugation and dried at 70°C for 5 hours to obtain hydrophobic modified titanium oxide.

[0074] In the above process, nano-titanium oxide is grafted with amino functional groups by reaction with N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, and the surface hydroxyl groups are not completely reacted. The hydroxyl groups are then reacted with perfluorooctyltrichlorosilane to graft hydrophobic groups to generate hydrophobic modified silica particles with surface hydrophobic groups and amino groups.

[0075] (2) Preparation of super-hydrophobic high-solid coatings and high-solid super-hydrophobic coatings

[0076] Select component A: polyaspartic acid ester, 40 parts; select component B: isocyanate curing agent HDI trimer, 45 parts; component C: hydrophobically modified titanium oxide 15 parts.

[0077] The polyaspartic acid resin of component A and the hydrophobically modified titanium oxide of component C are mixed and stirred thoroughly, and then the isocyanate curing agent of component B is added and stirred evenly to obtain a super hydrophobic high solid content coating;

[0078] The super-hydrophobic high-solid coating is immediately brushed or scraped onto the substrate, and a high-solid super-hydrophobic coating is obtained after drying. The hydrophobic performance of the coating is tested, and its water contact angle is 141°, which shows that its hydrophobic performance is good.

[0079] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A super hydrophobic high solid content coating, characterized in that: Its components are calculated by mass fraction as follows: 38-42 parts of polyaspartic acid; 41-47 parts of isocyanate curing agent; 11 to 21 parts of hydrophobically modified inorganic nanoparticles.

2. The super hydrophobic high solid content coating according to claim 1, characterized in that: The isocyanate curing agent is isocyanate HDI trimer.

3. The super hydrophobic high solid content coating according to claim 1, characterized in that: The hydrophobically modified inorganic nanoparticles are obtained by modifying the inorganic nanoparticles with a silane coupling agent containing an amino functional group and a fluorine-containing silane.

4. The super hydrophobic high solid content coating according to claim 3, characterized in that: The silane coupling agent is selected from one of 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane and N-2-aminoethyl-3-aminopropylmethyldimethoxysilane; The fluorine-containing silane is selected from one of heptadecafluorodecyltrimethoxysilane and perfluorooctyltrichlorosilane; The inorganic nanoparticles are one of nano silicon dioxide, nano calcium sulfate, nano zinc oxide or nano titanium oxide.

5. A method for preparing a super hydrophobic high solid content coating as claimed in any one of claims 1 to 4, characterized in that: The polyaspartic acid ester and the hydrophobically modified inorganic nanoparticles are mixed and stirred fully, and then an isocyanate curing agent is added and stirred evenly to obtain a super hydrophobic high-solid coating.

6. The preparation method of super hydrophobic high solid coating according to claim 5, characterized in that, The preparation process of the hydrophobically modified inorganic nanoparticles is as follows: S1, dissolving an amino-containing silane coupling agent in a solution of ethanol and deionized water, adjusting the pH to acidic, and magnetically stirring at room temperature to obtain a mixed solution, then adding inorganic nanoparticles to the mixed solution, mechanically stirring under heating conditions to fully react, collecting the reaction product by suction filtration or centrifugation, and vacuum drying the reaction product to obtain amino-modified nanoparticles; S2, dispersing the amino-modified nanoparticles in ethanol, adding fluorinated silane, and stirring fully at room temperature, then collecting the reaction product by suction filtration or centrifugation, and vacuum drying to obtain hydrophobically modified inorganic nanoparticles.

7. The preparation method of super hydrophobic high solid coating according to claim 6, characterized in that, In step S1: In the mixed solution, the mass ratio of the amino-containing silane coupling agent to ethanol and deionized water is 1:3.6-5.0:0.4-4.5; The mass ratio of the inorganic nanoparticles to the mixed solution is 1:10 to 50; The size of the inorganic nanoparticles is 10-100 nm.

8. The preparation method of super hydrophobic high solid coating according to claim 6, characterized in that, In step S1: When adjusting the pH to acidic, a weak acid is used to adjust the pH of the solution to 5.5-6.5; The magnetic stirring mixing time is 0.5 to 4 hours; The heating temperature is 80-90°C; the mechanical stirring time is 4-24h; During the vacuum drying, the drying temperature is 50-60° C. and the drying time is 1-12 hours.

9. The method for preparing a super hydrophobic high solid coating according to claim 6, wherein In the step S2, the mass ratio of the amino-modified nanoparticles, the fluorinated silane, and the ethanol is 1:0.2-0.6:10-100.

10. The method for preparing a super hydrophobic high solid coating according to claim 6, wherein: During the vacuum drying process of step S2, the drying temperature is 60-70° C. and the drying time is 1-12 hours.

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