Thin coating type polyurea coating and preparation method thereof

Abstract

The invention provides a thin coating type polyurea coating and a preparation method thereof. The thin coating type polyurea coating comprises a component A and a component B. The component A is prepared from, by mass, 100 parts of polyaspartic acid ester resin, 5-10 parts of nanoscale filler, 30-60 parts of micron inorganic filler, 0.5-1.0 part of defoaming agent, 0.5-1.5 parts of wetting dispersant, 0.5-1.5 parts of leveling agent and 20-30 parts of xylene. The component B is prepared from 30 to 40 parts of isocyanate N3390 with three degrees of functionality and 5 to 10 parts of isocyanate GB926 with two degrees of functionality. Nano-scale spherical and micron-scale flaky hydrophobic fillers are introduced, through multi-level filler compounding and introduction of nano-scale and micron-scale hydrophobic fillers, the excellent hydrophobic property of the coating is realized, and finally, the coating can show excellent water vapor barrier property under the condition of thin coating, so that a good protection effect on a matrix is realized; and water vapor infiltration is slowed down.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering, and in particular relates to a thin-coat polyurea coating and a preparation method thereof. Background Art

[0002] Paint films with high water vapor barrier properties usually need to have a denser molecular network structure and stronger van der Waals forces between molecules, thereby effectively reducing the permeation channels of water vapor.

[0003] Polyurea is a commonly used thick-coat waterproof coating with a thickness of usually more than 1 mm. Polyurea has the advantages of rapid curing, insensitivity to temperature and humidity of the construction environment, high construction efficiency, good toughness, and impact resistance. It has broad application prospects in the industrial field, but its water vapor barrier property is poor and cannot be compared with special water vapor barrier coatings such as ethylene-vinyl acetate copolymer (EVA) coatings.

[0004] Table 1 Water vapor barrier rate of common typical coating materials

[0005] Summary of the invention

[0006] In order to overcome the deficiencies in the prior art, the present invention provides a thin-coat polyurea coating and a preparation method thereof, wherein a trifunctional isocyanate is used as the main curing agent, and a difunctional isocyanate is used to adjust the flexibility of the material, thereby ultimately obtaining a polyurea coating with a high crosslinking density. Meanwhile, by introducing nano-scale spherical and micron-scale flaky hydrophobic fillers, by compounding multiple layers of fillers, and by introducing nano-scale and micron-scale hydrophobic fillers, the coating achieves excellent hydrophobic properties, thereby ultimately ensuring that the coating can exhibit excellent water vapor barrier properties when thinly coated, thereby achieving a good protective effect on the substrate and slowing down water vapor penetration.

[0007] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A thin-coat polyurea coating comprises two components, A and B. The components A have the following mass fractions: 100 parts of polyaspartic acid ester resin, 5-10 parts of nano-scale filler, 30-60 parts of micron inorganic filler, 0.5-1.0 parts of defoamer, 0.5-1.5 parts of wetting dispersant, 0.5-1.5 parts of leveling agent, and 20-30 parts of xylene; and the components B have the following mass fractions: 30-40 parts of trifunctional isocyanate N3390 and 5-10 parts of difunctional isocyanate GB926.

[0009] The polyaspartic acid ester resin is one or two of F420, F520 or F2850.

[0010] The nano-scale filler is surface hydrophobically modified white carbon black H2000.

[0011] The micron inorganic filler is at least one of talcum powder and boron nitride, and the surface is modified by heptadecafluorodecyltriethoxysilane.

[0012] The modification method is as follows: 100 mL of deionized water is added to 900-1000 mL of ethanol, ammonia water with a mass concentration of 25% is added to adjust the pH of the solution to 9-10, 80-100 g of micron inorganic filler is added after mixing evenly, 3.0-4.0 g of heptadecafluorodecyltriethoxysilane is added after further mixing evenly, magnetic stirring is performed at a speed of 800-1000 rmp for 24-28 hours, the obtained solution is dried, and the modified micron inorganic filler is obtained after grinding.

[0013] The wetting and dispersing agent is BYK-110.

[0014] The defoamer is one of BYK-1790 and BYK-028.

[0015] The leveling agent is one of BYK-306 and Tego Glide 450.

[0016] The preparation method of component A is as follows: (1) mixing and stirring the micron inorganic filler, the wetting and dispersing agent and xylene, transferring the mixture to a sand mill for grinding, and grinding the mixture 2-5 times to obtain a mixed slurry;

[0017] (2) The mixed slurry obtained in step (1), the nano-scale filler, the polyaspartic acid ester resin, the leveling agent, and the defoaming agent are uniformly mixed and transferred to a sand mill for grinding, and the grinding fineness is controlled to be below 40 μm to obtain component A.

[0018] A preparation method of a thin-coat polyurea coating is as follows: after uniformly mixing components A and B of the thin-coat polyurea coating, coating the coating on the surface of a substrate, curing the coating at room temperature for more than 72 hours or more than 24 hours, and heating and curing the coating at 60-80°C for more than 10 hours to obtain a thin-coat polyurea coating, wherein the coating method includes spraying, scraping, brushing, and rolling.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] (1) The present invention provides a thin-coat polyurea coating and a preparation method thereof, which realizes a molecular network structure with a high cross-linking density through the design of coating components. The strong intermolecular force between urea groups also lays a foundation for improving the water vapor barrier performance, while also ensuring the excellent mechanical properties of the coating;

[0021] (2) The present invention provides a thin-coat polyurea coating and a preparation method thereof, which greatly improves the hydrophobicity and film density of the coating surface by introducing hydrophobically modified nano-spherical and micron-flaky filler particles and compounding them at multiple levels, thereby greatly improving the water vapor barrier property of the coating;

[0022] (3) The present invention provides a thin-coat polyurea coating and a preparation method thereof, which has excellent mechanical properties, a simple preparation process, a coating solid content of ≥70% and can be cured at room temperature, is easy to construct, and can be applied on a large area by brushing, spraying, roller coating, dipping, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a comparison diagram of the microstructure of the paint film compactness of Comparative Example 1 and Example 1;

[0024] Figure 2 This is a comparison diagram of the hydrophobic angles of nano-silica before and after hydrophobic modification in Example 1;

[0025] Figure 3 This is a diagram of the hydrophobic effect of the coating surface in Example 1. DETAILED DESCRIPTION

[0026] Example 1

[0027] A component coating formula (mass fraction):

[0028]

[0029]

[0030] Component B (mass parts): N3390 30 parts, GB926 5 parts.

[0031] Among them, the modification method of modified talcum powder is as follows: add 100 mL of deionized water to 1000 mL of ethanol, add 25% ammonia water to adjust the pH of the solution to 10, mix well, add 100 g of talcum powder, further mix well, add 4.0 g of heptadecafluorodecyltriethoxysilane, stir magnetically at a speed of 1000 rpm for 24 hours, place the obtained solution in an oven at 100°C for drying, and grind to obtain the modified talcum powder.

[0032] The preparation method of component A coating is as follows:

[0033] 1) Mix the modified talcum powder, BYK-110 and xylene according to the proportion and stir them evenly, transfer them to a sand mill for grinding, and grind them 3 times to obtain a mixed slurry;

[0034] 2) The mixed slurry, H2000, F2850, BYK-1790 and Tego Glide 450 are mixed evenly according to a certain proportion, and transferred to a sand mill for grinding. After grinding, the grinding fineness is controlled to be below 40 μm to obtain component A.

[0035] The preparation method of the coating of this embodiment is as follows:

[0036] The obtained coating components A and B are mixed evenly, diluted with xylene, and then sprayed on the polished substrate surface, and cured at room temperature for more than 72 hours to achieve the preparation of a thin coating of about 150 μm.

[0037] Figure 1 The following is a comparison of the microstructure of the paint film compactness of Comparative Example 1 and Example 1. Figure 1 The lower part shows the microstructure of the paint film density of Example 1, and it can be seen that the paint film is dense and has no defects such as pores.

[0038] Figure 2 The figure shows the comparison of the hydrophobic angle of the filler before and after hydrophobic modification. It can be seen that the water contact angle increases significantly after hydrophobic modification. The filler changes from the surface hydrophilic state before modification to the surface hydrophobic state, and the surface contact angle after modification is 133.2°.

[0039] Figure 3 The figure shows the hydrophobic effect of the coating surface in Example 1. It can be seen that water is in a significant non-wetting and spreading state on the coating surface, and the hydrophobic effect is significant.

[0040] Example 2

[0041] A component coating formula (mass fraction):

[0042]

[0043] Component B (mass fractions): 35 parts of N3390 and 8.3 parts of GB926.

[0044] Among them, the modification method of modified boron nitride is as follows: 100 mL of deionized water is added to 1000 mL of ethanol, 25% ammonia water is added to adjust the pH of the solution to 10, 100 g of boron nitride powder is added after mixing evenly, 3.0 g of heptadecafluorodecyltriethoxysilane is added after further mixing evenly, and the solution is placed in an oven at 100 ° C. and dried after grinding to obtain the modified boron nitride powder.

[0045] The preparation method of component A coating is as follows:

[0046] 1) Mix the modified boron nitride powder, BYK-110 and xylene according to the proportion and stir them evenly, transfer them to a sand mill for grinding, and grind them 3 times to obtain a mixed slurry;

[0047] 2) The mixed slurry, H2000, F420, BYK-1790 and BYK-306 are mixed evenly according to a certain proportion, and transferred to a sand mill for grinding. After grinding, the grinding fineness is controlled to be below 40 μm to obtain component A.

[0048] The preparation method of the coating of this example is as follows:

[0049] The obtained coating components A and B are mixed evenly, diluted with xylene, and then sprayed on the polished substrate surface, and cured at room temperature for more than 72 hours to achieve the preparation of a thin coating of about 150 μm.

[0050] Comparative Example 1

[0051] This comparative example is consistent with Example 1, except that the coating formulation uses unmodified white carbon black instead of H2000.

[0052] Figure 1 The upper part shows the microstructure of the paint film of Comparative Example 1. It can be seen that the paint film has poor density and has significant microscopic defects such as pores, which is the core reason for the poor density of the paint film.

[0053] Comparative Example 2

[0054] This comparative example is consistent with Example 1, except that the coating formula uses unmodified talcum powder.

[0055] The coating performance test results of Examples 1-2 and Comparative Examples 1-2 are shown in Table 2:

[0056] Table 2 Coating performance test results of Examples 1-2 and Comparative Examples 1-2

[0057]

[0058] In summary, compared with Comparative Examples 1 and 2, Example 1 and Example 2 have excellent hydrophobicity through the hydrophobic modification of the filler, and the hydrophobic angles are both above 140°, and both have low water vapor permeability and excellent water vapor barrier properties. At the same time, the filler modification makes the filler have excellent mechanical properties, which is mainly due to the surface modification of the filler to improve the compatibility with the resin and reduce the internal defects of the system.

[0059] The above description is only the best specific implementation mode 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 any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0060] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A thin-coat polyurea coating, characterized in that: The invention comprises two components, A and B. The components A have the following weight proportions: 100 parts of polyaspartic acid ester resin, 5 to 10 parts of nano-scale filler, 30 to 60 parts of micron inorganic filler, 0.5 to 1.0 parts of defoamer, 0.5 to 1.5 parts of wetting and dispersing agent, 0.5 to 1.5 parts of leveling agent and 20 to 30 parts of xylene; the components B have the following weight proportions: 30 to 40 parts of trifunctional isocyanate N3390 and 5 to 10 parts of difunctional isocyanate GB926.

2. The thin-coat polyurea coating according to claim 1, characterized in that: The polyaspartic acid ester resin is one or two of F420, F520 or F2850.

3. The thin-coat polyurea coating according to claim 1, characterized in that: The nano-scale filler is surface hydrophobically modified white carbon black H2000.

4. The thin-coat polyurea coating according to claim 1, characterized in that: The micron inorganic filler is at least one of talcum powder and boron nitride, and the surface is modified by heptadecafluorodecyltriethoxysilane.

5. The thin-coat polyurea coating according to claim 4, characterized in that: The modification method is as follows: 100 mL of deionized water is added to 900-1000 mL of ethanol, ammonia water with a mass concentration of 25% is added to adjust the pH of the solution to 9-10, 80-100 g of micron inorganic filler is added after mixing evenly, 3.0-4.0 g of heptadecafluorodecyltriethoxysilane is added after further mixing evenly, magnetic stirring is performed at a speed of 800-1000 rmp for 24-28 hours, the obtained solution is dried, and the modified micron inorganic filler is obtained after grinding.

6. The thin-coat polyurea coating according to claim 1, characterized in that: The wetting and dispersing agent is BYK-110.

7. The thin-coat polyurea coating according to claim 1, characterized in that: The defoamer is one of BYK-1790 and BYK-028.

8. The thin-coat polyurea coating according to claim 1, characterized in that: The leveling agent is one of BYK-306 and Tego Glide 450.

9. The thin-coat polyurea coating according to claim 1, characterized in that: The preparation method of component A is as follows: (1) mixing and stirring the micron inorganic filler, the wetting and dispersing agent and xylene, transferring the mixture to a sand mill for grinding, and grinding the mixture 2-5 times to obtain a mixed slurry; (2) The mixed slurry obtained in step (1), the nano-scale filler, the polyaspartic acid ester resin, the leveling agent, and the defoaming agent are uniformly mixed and transferred to a sand mill for grinding, and the grinding fineness is controlled to be below 40 μm to obtain component A.

10. A method for preparing a thin-coat polyurea coating, characterized in that: After uniformly mixing the components A and B of the thin-coat polyurea coating according to any one of claims 1 to 9, the components are applied to the surface of the substrate, cured at room temperature for more than 72 hours or more than 24 hours, and heated at 60 to 80°C for more than 10 hours to obtain a thin-coat polyurea coating, wherein the coating method includes spraying, scraping, brushing, and rolling.

11. A thin-coat polyurea coating, characterized in that: Prepared according to the preparation method according to claim 10.

Images