Solvent-free dual-curing asparaginic acid ester polyurea coating as well as preparation method and application thereof

Abstract

The invention provides a solvent-free dual-curing asparaginic acid ester polyurea coating as well as a preparation method and application thereof, and relates to the field of coatings. The coating comprises a component A and a component B in percentage by mass, the component A is prepared from the following raw materials: 30 to 95 percent of polyaspartic acid ester resin, 0.2 to 0.8 percent of dispersing agent, 0.1 to 1.0 percent of defoaming agent, 0.1 to 0.3 percent of flatting agent, 0.3 to 1.0 percent of fumed silica, 5 to 10 percent of molecular sieve, 30 to 50 percent of barium sulfate, 0 to 10 percent of coupling agent, 0 to 5 percent of anti-skid particle powder and 0 to 20 percent of color paste; the component B comprises a siloxane modified isocyanate curing agent, and the mass fraction of the curing agent is 30-100%. The quick-drying property of the polyaspartic acid ester polyurea is maintained, and the quick-drying paint not only has good adhesive force to matt finish tiles used in toilets, but also has good adhesive force to smooth tiles.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically, to a solvent-free, dual-curing aspartic ester polyurea coating, its preparation method, and its application. Background Technology

[0002] Tiles, with their excellent stain resistance, ease of cleaning, and long lifespan, are currently the preferred choice for home decoration (including kitchens and bathrooms). Kitchens and bathrooms, due to their constant contact with water, have very high requirements for waterproofing. However, in reality, leaks and seepage occur in kitchens and bathrooms for various reasons. Finding leaks and seepage often requires dismantling or breaking tiles, which is not only time-consuming and laborious but also expensive. Furthermore, a new waterproofing layer needs to be applied internally afterward, which again introduces the risk of leaks and seepage. Therefore, developing a technology that effectively stops leaks and seepage without dismantling or breaking tiles would not only have significant social benefits but also bring substantial economic returns.

[0003] Polyaspartic acid ester polyurea is a new generation of polyurea composed of secondary amine groups and isocyanate curing agents. It features low viscosity and fast drying, good waterproofing, corrosion resistance, and transparency, excellent abrasion resistance, and weather resistance comparable to fluorocarbon resins. Its low viscosity and fast drying properties ensure solvent-free, environmentally friendly construction and rapid deployment; its good transparency preserves the original color of the tile; and its excellent weather resistance and stable chemical bonds provide long-lasting waterproof protection. However, traditional polyaspartic acid ester polyurea has insufficient adhesion to tiles, easily causing large-scale peeling. Furthermore, maintaining its fast drying properties often requires the addition of solvents to extend the construction time.

[0004] CN115895421A discloses a transparent, solvent-free, non-smash-resistant waterproof coating. This waterproof coating is a polyaspartic acid ester polyurea coating, which improves adhesion by delaying the drying speed to increase wetting time. Specifically, the method involves purifying the low-viscosity polyaspartic acid ester resin to reduce primary amine residue, thereby reducing sensitivity to moisture and lowering reactivity. The low viscosity and low primary amine residue of the resin extend the application time, thus improving adhesion. However, this method has limited effect on improving substrate adhesion and prolongs both surface drying and complete drying times.

[0005] CN115975493A discloses a wear-resistant, transparent, and environmentally friendly waterproof coating for bathrooms. This waterproof coating is a two-component coating. Component A consists of hydroxypropyl resin, polyaspartic acid ester resin, a latently active diluent, and additives. Component B is a curing agent modified with polytetrahydrofuran alcohol and isophorone diisocyanate. The latently active diluent in component A is preferably butyrylylene-branched epichlorohydrin to reduce application viscosity; the mixture of hydroxypropyl resin and polyaspartic acid ester resin is used to balance weather resistance and cost; and the polytetrahydrofuran alcohol-modified isophorone curing agent is used to coordinate hardness and flexibility. However, specific effects and data are not listed.

[0006] CN118085550B discloses a no-tile-removal waterproofing agent and its application in bathroom leak repair. This waterproofing agent is a silicone emulsion and a hydrophobic silica dispersion. The low molecular weight silicone emulsion and hydrophobic silica penetrate from the tile grout into the interior of the tile, then adhere to the concrete mortar surface to form a hydrophobic layer. Simultaneously, it penetrates into the concrete grout and micropores, thereby improving waterproofing performance. Essentially, it strengthens the adhesion between the tile and the concrete, rather than forming a monolithic protective layer on the tile for waterproofing. Summary of the Invention

[0007] The purpose of this invention is to provide a solvent-free, dual-curing aspartic ester polyurea coating that, while maintaining the fast-drying properties of polyaspartic ester polyurea, achieves long-term solvent-free application and good adhesion to ceramic tile substrates. It exhibits good adhesion not only to matte ceramic tiles used in bathrooms but also to glossy ceramic tiles.

[0008] Another objective of this invention is to provide a method for preparing a solvent-free, dual-curing aspartic ester polyurea coating, wherein the prepared coating has strong adhesion to the ceramic tile substrate.

[0009] The technical problem solved by this invention is achieved by the following technical solution.

[0010] On one hand, embodiments of the present invention provide a solvent-free, dual-curing aspartic ester polyurea coating, comprising component A and component B. By mass fraction, component A comprises the following raw materials: 30-95% polyaspartic acid ester resin, 0.2-0.8% dispersant, 0.1-1.0% defoamer, 0.1-0.3% leveling agent, 0.3-1.0% fumed silica, 5-10% molecular sieve, 30-50% barium sulfate, 0-10% coupling agent, 0-5% anti-slip granular powder, and 0-20% color paste; Component B includes a siloxane-modified isocyanate curing agent with a solid content of 95-100%. The mass ratio of component A to component B is A:B = 1:(1-1.2).

[0011] In some embodiments of the present invention, the coupling agent is a methoxysilane coupling agent or an ethoxysilane coupling agent. The coupling agent can be any compound containing methoxysilane or ethoxysilane.

[0012] In some embodiments of the present invention, the polyaspartic ester resin may be one or more of the commercially available brands, such as at least one of Desmophen® NH 1520, Desmophen® NH 1420, F520, F420, F2850, and F2401.

[0013] On the other hand, embodiments of the present invention provide a method for preparing a solvent-free, dual-curing aspartic ester polyurea coating, comprising the following steps: S1 Preparation of Siloxane-Modified Isocyanate Curing Agent: Epoxy-containing siloxanes are reacted with secondary amine compounds to obtain hydroxyl-terminated siloxane modifiers; then, the hydroxyl-terminated siloxane modifiers are added to HDI trimers, heated to 50-90℃, and kept at that temperature for 3-12 hours to obtain siloxane-modified isocyanate curing agents. S2 preparation of coatings: The polyaspartic ester resin, dispersant, defoamer, and leveling agent are mixed evenly using a high-speed disperser at a speed of 1000-1200 r / min for 10-15 min according to the mass ratio. Then, the remaining raw materials of component A are added and mixed evenly at a speed of 2000-2500 r / min for 30-40 min to obtain component A. Then, component B is added and mixed evenly to obtain the polyaspartic ester polyurea coating.

[0014] In some embodiments of the present invention, the mass percentage of -NCO in the siloxane-modified isocyanate curing agent is 10-15%.

[0015] In some embodiments of the present invention, the epoxy-containing siloxane is a siloxane with a monoepoxy functional group.

[0016] In some embodiments of the present invention, the epoxy-containing siloxane is at least one of trimethoxysilane, triethoxysilane, dimethoxysilane, and diethoxysilane.

[0017] In some embodiments of the present invention, the secondary amine group of the secondary amine compound is a monofunctional group; The secondary amine compound is an aliphatic secondary amine compound. The secondary amine compound can be one or more of acyclic aliphatic secondary amine compounds and cyclic aliphatic secondary amine compounds.

[0018] In some embodiments of the present invention, the HDI trimer is at least one of HT-300, HT-600, HT-100, N3900, N3300, and N3600.

[0019] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: 1. This invention achieves long-term solvent-free application and excellent adhesion to ceramic tile substrates while maintaining the fast-drying properties of polyaspartic ester polyurea. This is due to the establishment of a dual-curing system that balances sufficient wetting and rapid curing. The dual-curing system primarily utilizes the secondary amine in the aspartic ester and the isocyanate curing agent for curing, achieving rapid surface and complete drying of the coating. Meanwhile, the condensation polymerization of the siloxane acts as an auxiliary curing agent, extending the wetting time of the coating on the ceramic tile substrate and bridging it with the substrate through chemical bonds, thus achieving excellent adhesion to the ceramic tile substrate while maintaining rapid drying.

[0020] 2. The dual-curing polyaspartic ester polyurea prepared in this invention can be applied to ceramic tiles using solvent-free roller or brush coating. It achieves rapid drying characteristics, with surface drying in 1 hour and complete drying in 3 hours, while maintaining a 30-minute application time. This is because the selected low-viscosity resin provides a flowable base for solvent-free application, while the siloxanes fixed to the resin backbone and the free siloxanes reduce the surface tension of the coating, making it easier to level.

[0021] 3. The solvent-free, dual-curing aspartic ester polyurea prepared in this invention exhibits excellent adhesion not only to matte tiles used in bathrooms but also to glossy tiles. This is due, in part, to the organic portion of the cured polyurea in the dual-curing system providing initial adhesion between the coating and the tile substrate. Furthermore, in the later stages of curing, the siloxanes on the resin backbone, free siloxanes, and the tile surface undergo inorganic-inorganic chemical bridging. Initially, the dual curing process primarily relies on the secondary amine in the aspartic ester and the cyanate ester curing agent. As curing progresses, a three-dimensional cross-linked network forms between the resin and the curing agent, locking the backbone molecules and restricting their migration. The free siloxanes, with their low surface energy and slow condensation reaction, retain migration capability for a considerable period, thus enhancing wetting of the substrate. In the later stages of curing, the hydrolysis of siloxanes leads to condensation bridging between the siloxanes on the backbone and the free siloxanes, anchoring them to the tile surface, further enhancing adhesion and increasing the overall cross-linking degree of the coating. While standalone free siloxanes can enhance the adhesion between the coating and the substrate, they cannot anchor the tile and the substrate in the form of stable chemical bonds. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a picture of the actual product after the cross-cut adhesion test of Example 3, where the coating was applied to a smooth ceramic tile with a thickness of 200µm. Figure 2 This is a picture of the actual product after scraping and scraping with a scraper onto a smooth ceramic tile in Example 3, with a thickness of 200µm. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0026] Example 1 A method for preparing a siloxane-modified isocyanate curing agent is as follows: S1 Preparation of Siloxane-Modified Isocyanate Curing Agent In a nitrogen atmosphere below 60°C, excess diethyl maleate was titrated into dodecylamine, and the mixture was kept at this temperature for 2 hours after the addition was complete. Then, the temperature was gradually increased, and the mixture was kept at 80-90°C for 72-120 hours to obtain a mono-secondary amine compound with a solid content of over 95 wt%. Next, the temperature was increased to 60-140°C, and trimethylsiloxane KH560 was added dropwise, keeping the mixture at this temperature for 12-48 hours to obtain a hydroxyl-terminated siloxane-modified compound. Finally, the hydroxyl-terminated siloxane-modified compound was added to HT-600 trimer, and the temperature was increased to 50-90°C, keeping the mixture at this temperature for 3-12 hours to obtain a siloxane-modified isocyanate curing agent with an NCO mass percentage of 14%.

[0027] S2 Preparation of Double Crosslinked Polyaspartic Ester Polyurea Coating The following mass ratios were used: F520:F2850:dispersant BYK-163:defoamer BYK-1790:defoamer Tego airex 900:leveling agent TEG0-410:silane coupling agent:fumed silica DM-10:molecular sieve 3A activated powder:barium sulfate:color paste = 30:15:0.8:0.3:0.2:1:0.1:0.5:5:42.1:5. F520, F420, dispersant, defoamer, and leveling agent were mixed uniformly at high speed using a high-speed disperser at 1000 r / min for 10 min. Then, fumed silica, molecular sieve, barium sulfate, and color paste were added, and the mixture was stirred at 2000 r / min for 30 min to obtain component A. Next, the components A and siloxane-modified isocyanate curing agent were mixed at a mass ratio of 1:1 to obtain polyaspartic acid ester polyurea coating.

[0028] Example 2: A method for preparing a siloxane-modified isocyanate curing agent is as follows: S1 Preparation of Siloxane-Modified Isocyanate Curing Agent In a nitrogen atmosphere below 60°C, excess diethyl maleate was titrated into dodecylamine, and the mixture was kept at this temperature for 2 hours after the addition was complete. Then, the temperature was gradually increased, and the mixture was kept at 80-90°C for 72-120 hours to obtain a polyaspartic acid ester with a solid content of over 95 wt%. Next, the temperature was increased to 60-140°C, and trimethylsiloxane KH560 was added dropwise, keeping the mixture at this temperature for 12-48 hours to obtain a hydroxyl-terminated siloxane-modified product. Finally, the hydroxyl-terminated siloxane-modified product was added to HT-600 trimer, and the temperature was increased to 50-90°C, keeping the mixture at this temperature for 3-12 hours to obtain a siloxane-modified isocyanate curing agent with an NCO mass percentage of 12%.

[0029] S2 Preparation of Double Crosslinked Polyaspartic Ester Polyurea Coating The following mass ratios were used: F520:F2850:dispersant BYK-163:defoamer BYK-1790:defoamer Tego airex 900:leveling agent TEG0-410:silane coupling agent:fumed silica DM-10:molecular sieve 3A activated powder:barium sulfate:color paste = 30:15:0.8:0.3:0.2:1:0.1:0.5:5:42.1:5. F520, F420, dispersant, defoamer, and leveling agent were mixed uniformly at high speed using a high-speed disperser at 1000 r / min for 10 min. Then, fumed silica, molecular sieve, barium sulfate, and color paste were added, and the mixture was stirred at 2000 r / min for 30 min to obtain component A. Next, the components A and siloxane-modified isocyanate curing agent were mixed at a mass ratio of 1:1.15 to obtain polyaspartic acid ester polyurea coating.

[0030] Example 3: A method for preparing a siloxane-modified isocyanate curing agent is as follows: S1 Preparation of Siloxane-Modified Isocyanate Curing Agent In a nitrogen atmosphere below 60°C, excess diethyl maleate was titrated into dodecylamine, and the mixture was kept at this temperature for 2 hours after the addition was complete. Then, the temperature was gradually increased, and the mixture was kept at 80-90°C for 72-120 hours to obtain a polyaspartic acid ester with a solid content of over 95 wt%. Next, the temperature was increased to 60-140°C, and trimethylsiloxane KH560 was added dropwise, keeping the mixture at this temperature for 12-48 hours to obtain a hydroxyl-terminated siloxane-modified product. Finally, the hydroxyl-terminated siloxane-modified product was added to HT-600 trimer, and the temperature was increased to 50-90°C, keeping the mixture at this temperature for 3-12 hours to obtain an isocyanate curing agent with an NCO mass percentage of 12% modified siloxane.

[0031] S2 Preparation of Double Crosslinked Polyaspartic Ester Polyurea Coating The components F520, F420, dispersant, defoamer, and leveling agent were mixed at high speed using a high-speed disperser at a speed of 1000 r / min for 10 min. The mass ratios were: F520:F2850: dispersant BYK-163: defoamer BYK-1790: defoamer Tego airex 900: leveling agent TEG0-410: silane coupling agent: fumed silica DM-10: molecular sieve 3A activated powder: barium sulfate: color paste = 22.5:22.5:0.8:0.3:0.2:1:0.1:0.5:5:42.1:5. F520, F420, dispersant, defoamer, and leveling agent were then mixed uniformly at high speed using a high-speed disperser at 1000 r / min for 10 min. Then, fumed silica, molecular sieve, barium sulfate, and color paste were added, and the mixture was stirred at 2000 r / min for 30 min to obtain component A. Next, the components A and siloxane-modified isocyanate curing agent were mixed at a mass ratio of 1:1.15 to obtain polyaspartic acid ester polyurea coating.

[0032] Comparative Example 1: In a nitrogen atmosphere below 60°C, excess diethyl maleate was titrated into dodecylamine, and the mixture was kept at this temperature for 2 hours after the addition was complete. Then, the temperature was gradually increased, and the mixture was kept at 80-90°C for 72-120 hours to obtain a mono-secondary amine compound with a solid content of over 95 wt%. Next, the temperature was increased to 60-140°C, and the epoxy monomer AGE was added dropwise, keeping the mixture at this temperature for 12-48 hours to obtain a hydroxyl-terminated modified product. Finally, the hydroxyl-terminated siloxane modified product was added to HT-600 trimer, and the temperature was increased to 50-90°C, keeping the mixture at this temperature for 3-12 hours to obtain a siloxane-modified isocyanate curing agent with an NCO mass percentage of 12%.

[0033] Preparation of polyaspartic acid ester polyurea coating: The mass ratio of F520:F2850: dispersant BYK-163: defoamer BYK-1790: defoamer Tego airex 900: leveling agent TEG0-410: silane coupling agent: fumed silica DM-10: molecular sieve 3A activated powder: barium sulfate: pigment paste = 22.5:22.5:0.8:0.3:0.2:1:0.1:0.5:5:42.1:5 was used. F520, F420, dispersant, defoamer, and leveling agent were mixed uniformly at high speed using a high-speed disperser at 1000 r / min for 10 min. Then, fumed silica, molecular sieve, barium sulfate, and pigment paste were added, and the mixture was stirred at 2000 r / min for 30 min to obtain component A. Next, the components A and HT-600 modified with hydroxyl-terminated compounds were mixed at a mass ratio of 1:1.15 to obtain polyaspartic acid ester polyurea coating.

[0034] Comparative Example 2: Preparation of polyaspartic acid ester polyurea coating: The mass ratio of F520:F2850: dispersant BYK-163: defoamer BYK-1790: defoamer Tego airex 900: leveling agent TEG0-410: silane coupling agent: fumed silica DM-10: molecular sieve 3A activated powder: barium sulfate: pigment paste = 22.5:22.5:0.8:0.3:0.2:1:0.1:0.5:5:42.1:5 was used. F520, F420, dispersant, defoamer, and leveling agent were mixed uniformly at high speed using a high-speed disperser at 1000 r / min for 10 min. Then, fumed silica, molecular sieve, barium sulfate, and pigment paste were added, and the mixture was stirred at 2000 r / min for 30 min to obtain component A. Next, the components A and HT-600 were mixed at a mass ratio of 1:0.6 to obtain a polyaspartic acid ester polyurea coating.

[0035] Example of results: The coatings of Examples 1, 2, and 3 and Comparative Examples 1 and 2 were tested, and the following test results were obtained: Table 1 Comparison of parameters for no-brick-removal polyurea coatings

[0036] The test results above show that by adjusting the amount of hydroxyl-terminated siloxane modified HT-600 in the curing agent and the combination of different types of polyaspartic ester resin, the polyurea coating prepared by the siloxane-modified isocyanate curing agent combined with polyaspartic ester resin can achieve long-term (30 min) solvent-free application and good adhesion (adhesion level 0) to smooth ceramic tile substrates while maintaining the fast-drying (60 min surface dry, 180 h hard dry) characteristics of polyaspartic ester polyurea. The data above show that the isocyanate curing agent modified with hydroxyl-terminated compounds (Examples 1, 2, 3 and Comparative Example 1) has higher reactivity than the unmodified curing agent HT-600 (Comparative Example 2), thus extending the construction time and improving the adhesion to the tile substrate.

[0037] The data above shows that, compared with the hydroxyl-terminated non-siloxane modified isocyanate curing agent (Comparative Example 1), the hydroxyl-terminated siloxane modified isocyanate curing agent (Examples 1-3) has higher adhesion to the ceramic tile substrate; and Example 3 not only has good adhesion to smooth ceramic tiles, but also solves the problem of polyaspartic acid ester polyurea peeling off completely, as shown in the attached figure. Figure 1-2 As shown, the scraper only scrapes off small pieces, rather than removing the entire piece.

[0038] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A solvent-free, dual-curing aspartic ester polyurea coating, characterized in that, It includes component A and component B, with a mass ratio of component A to component B of 1:(1-1.2). By mass fraction, component A comprises the following raw materials: 30-95% polyaspartic acid ester resin, 0.2-0.8% dispersant, 0.1-1.0% defoamer, 0.1-0.3% leveling agent, 0.3-1.0% fumed silica, 0-10% molecular sieve, 0-50% barium sulfate, 0-10% coupling agent, 0-5% anti-slip granular powder, and 0-20% color paste; Component B includes a siloxane-modified isocyanate curing agent with a solid content of 95-100%.

2. The solvent-free, dual-curing aspartic ester polyurea coating according to claim 1, characterized in that, The coupling agent is a methoxysilane coupling agent or an ethoxysilane coupling agent.

3. The solvent-free, dual-curing aspartic ester polyurea coating according to claim 1, characterized in that, The polyaspartic acid ester resin is at least one of Desmophen® NH 1520, Desmophen® NH 1420, F520, F420, F2850, and F2401.

4. A method for preparing a solvent-free, dual-curing aspartic ester polyurea coating as described in any one of claims 1-3, characterized in that, Includes the following steps, S1 Preparation of Siloxane-Modified Isocyanate Curing Agent: Epoxy-containing siloxanes are reacted with secondary amine compounds to obtain hydroxyl-terminated siloxane modified products. The hydroxyl-terminated siloxane modifier is then added to the HDI trimer, heated to 50-90℃, and kept at that temperature for 3-12 hours to obtain the siloxane-modified isocyanate curing agent. S2 preparation of coatings: The polyaspartic ester resin, dispersant, defoamer, and leveling agent are mixed evenly using a high-speed disperser at a speed of 1000-1200 r / min for 10-15 min according to the mass ratio. Then, the remaining raw materials of component A are added and mixed evenly at a speed of 2000-2500 r / min for 30-40 min to obtain component A. Then, component B is added and mixed evenly to obtain the polyaspartic ester polyurea coating.

5. The method for preparing the solvent-free dual-curing aspartic ester polyurea coating according to claim 4, characterized in that, The siloxane-modified isocyanate curing agent contains 10-15% -NCO by mass.

6. The method for preparing the solvent-free dual-curing aspartic ester polyurea coating according to claim 4, characterized in that, The epoxide-containing siloxane is a siloxane with a monoepoxide functional group.

7. The method for preparing the solvent-free dual-curing aspartic ester polyurea coating according to claim 4, characterized in that, The epoxy-containing siloxane is at least one of trimethoxysilane, triethoxysilane, dimethoxysilane, and diethoxysilane.

8. The method for preparing the solvent-free dual-curing aspartic ester polyurea coating according to claim 4, characterized in that, The secondary amine group in the compound is a monofunctional group; The secondary amine compound is an aliphatic secondary amine compound.

9. The method for preparing the solvent-free dual-curing aspartic ester polyurea coating according to claim 4, characterized in that, The HDI trimer is at least one of HT-300, HT-600, HT-100, N3900, N3300, and N3600.

10. The application of a solvent-free, dual-curing aspartic ester polyurea coating as described in any one of claims 1-3, or / and a coating prepared by the method described in any one of claims 4-9, characterized in that, Used for waterproofing tiles.

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