Waterborne epoxy floor finish paint and preparation process thereof

Abstract

The invention relates to the technical field of floor coatings, and discloses a waterborne epoxy floor finish paint and a preparation process thereof, and the preparation process comprises the following steps: designing and synthesizing a macromolecular amine curing agent based on a click reaction mechanism of sulfydryl-alkenyl and an acylation reaction mechanism of amino-carboxyl; the macromolecular amine curing agent is an aliphatic chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent; the water-based epoxy floor finish paint is prepared by taking a water-based epoxy resin emulsion as a film forming component and taking an aliphatic chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent as a cross-linking curing component, the water-based epoxy floor finish paint has excellent water resistance and corrosion resistance, and all the properties meet the technical requirements specified by the GB / T 22374-2018 standard. The comprehensive performance is excellent, and the practical value is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of floor coatings, and specifically to a waterborne epoxy floor topcoat and its preparation process. Background Art

[0002] Epoxy resin coatings have the characteristics of relatively low cost, good abrasion resistance and high adhesion, and are often widely used as floor topcoats in the field of industrial floor coatings. With the continuous improvement of people's environmental awareness, epoxy floor coatings are gradually developing from traditional solvent-based coatings with high VOC content to environmentally friendly waterborne coatings with low toxicity and non-toxicity. Waterborne epoxy coatings use water as the dispersion medium, which is safe and reliable during storage, transportation and use, and has good construction operability. It has great potential, significance and application prospects, and has become the first choice in the floor coating market.

[0003] For waterborne epoxy coatings to obtain a uniform, stable and smooth coating, the curing agent plays a crucial role. The most widely used curing agent in waterborne epoxy coatings is amine curing agent. Traditional small-molecule amine curing agents generally have disadvantages such as too high reaction activity, short pot life, high toxicity and easy volatility, which will cause poor phenomena such as holes on the surface of the epoxy resin coating. Therefore, it is usually necessary to modify traditional small-molecule amine curing agents to meet the actual use requirements. Amine-modified waterborne epoxy curing agents can be mainly divided into three categories: amidated polyamines, polyamides and polyamine-epoxy resin complexes.

[0004] Waterborne epoxy curing agents use water as a solvent. Compared with organic solvents, water has higher heat of vaporization and surface tension, which makes the film-forming and drying time of waterborne epoxy curing agents longer and the wetting and dispersing performance poorer. When making paint, more small-molecule additives need to be added to help film formation, but this will reduce the water resistance and corrosion resistance of the coating film. Therefore, it is necessary to modify waterborne epoxy curing agents. Commonly used modification methods include organosilicon modification, polyurethane modification and Mannich amine modification. The Si-O bond in organosilicon is highly polar. Introducing it into epoxy resin can significantly enhance its water resistance and corrosion resistance, thereby improving the performance and application range of the epoxy system. Summary of the Invention

[0005] The present invention independently developed a macromolecular amine curing agent to replace the existing commercial small-molecule amine curing agent. Using the macromolecular amine curing agent as the curing agent to promote the curing and crosslinking of waterborne epoxy resin, a waterborne epoxy floor topcoat is prepared, which has excellent water resistance and corrosion resistance, and meets the technical requirements specified in the standard of GB / T 22374-2018 "Floor Coating Materials".

[0006] A preparation process of a waterborne epoxy floor topcoat includes the following steps: Step 1: Prepare a macromolecular amine curing agent, which is a fatty chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent; Step 2: Use an aqueous epoxy resin emulsion as the film-forming component and a fatty chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent as the cross-linking and curing component to prepare an aqueous epoxy floor topcoat.

[0007] Preferably, the preparation method of the fatty chain siloxane type macromolecular amine curing agent is as follows: In the presence of a photoinitiator, the alkenyl functional groups of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane react with the mercapto functional groups of 2.01 - 2.09 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light through a click reaction to generate a dicarboxylic monomer; Using the mechanism of nucleophilic substitution reaction, the carboxyl functional groups of 1 molar equivalent of the dicarboxylic monomer and the amino functional groups of 2.01 - 2.09 molar equivalents of hexamethylenediamine are catalyzed by an organic base catalyst to undergo acylation reaction to generate a fatty chain siloxane type macromolecular amine curing agent.

[0008] Preferably, the photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone.

[0009] Preferably, the preparation method of the aromatic etherified siloxane type macromolecular amine curing agent is as follows: Using the mechanism of nucleophilic substitution reaction, the carboxyl functional groups of 1 molar equivalent of the dicarboxylic monomer and the amino functional groups of 2.01 - 2.09 molar equivalents of 4,4'-diaminodiphenyl ether are catalyzed by an organic base catalyst to undergo acylation reaction to generate an aromatic etherified siloxane type macromolecular amine curing agent.

[0010] Preferably, the organic base catalyst is one of pyridine, triethylamine, tributylamine, and imidazole.

[0011] An aqueous epoxy floor topcoat prepared according to the above process, the aqueous epoxy floor topcoat includes component A and component B; The formula of component A is: 10 - 20 parts by weight of water, 5 - 10 parts by weight of talc powder, 10 - 15 parts by weight of barium sulfate, 45 - 55 parts by weight of aqueous epoxy resin emulsion, 5 - 8 parts by weight of aluminum tripolyphosphate, 5 - 8 parts by weight of mica powder, and 0.5 - 5 parts by weight of a composite additive; The formula of component B is: 25 - 30 parts by weight of macromolecular amine curing agent and 70 - 80 parts by weight of water.

[0012] Preferably, the mass ratio of component A to component B in the waterborne epoxy floor topcoat is (3 - 5):1.

[0013] Preferably, the composite auxiliary agent includes a wetting agent, a dispersing agent, an antifoaming agent and a thickening agent. Beneficial effects

[0014] Based on the click reaction mechanism of thiol-alkene and the acylation reaction mechanism of amino-carboxyl, the present invention designed and synthesized two kinds of macromolecular amine curing agents (aliphatic chain-siloxane type macromolecular amine curing agent and aromatic ether-siloxane type macromolecular amine curing agent); Using the aliphatic chain-siloxane type macromolecular amine curing agent or the aromatic ether-siloxane type macromolecular amine curing agent as the crosslinking and curing component of the waterborne epoxy resin emulsion, a waterborne epoxy floor topcoat was prepared. From the performance test results, it can be seen that: the waterborne epoxy floor topcoat prepared by the present invention has excellent water resistance and corrosion resistance, and all performances meet the technical requirements specified in the GB / T 22374-2018 standard, with relatively excellent comprehensive performance and practical value. Specific embodiments

[0015] The present invention designed and synthesized two kinds of macromolecular amine curing agents. On the one hand, their molecular structures contain both hydrophilic amine groups and amide groups and hydrophobic alkyl carbon chains and aromatic rings at the same time. It is a typical amphiphilic surfactant, with certain emulsifying properties, water dispersibility and low toxicity. On the other hand, their molecular structures also contain organosilicon structures. The Si-O bond in the organosilicon structure has a very strong polarity, which can significantly enhance the water resistance and corrosion resistance of epoxy resins. On the third hand, the benzene ring structure contained in their molecular structures can increase their compatibility with epoxy resins. Experimental example 1:

[0016] Prepare an aliphatic chain-siloxane type macromolecular amine curing agent, and its preparation method is as follows: The first step: In the presence of a photoinitiator, the alkenyl functional groups of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane react with the thiol functional groups of 2.05 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light to generate a dicarboxyl monomer, and its chemical structural formula is: ; Among them, the photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2,2-diethoxyacetophenone; in this embodiment, 2,2-dimethoxy-2-phenylacetophenone is selected for use; Step 2: Using the nucleophilic substitution reaction mechanism, the carboxyl functional groups of 1 molar equivalent of dicarboxylic acid monomers and the amino functional groups of 2.08 molar equivalents of hexamethylenediamine are catalyzed by an organic base catalyst to undergo an acylation reaction to produce a fatty-chain silicone-oxygen alkane type macromolecular amine curing agent, and its chemical structural formula is: ; Among them, the organic base catalyst is one of pyridine, triethylamine, tributylamine, and imidazole. In this example, triethylamine is selected for use; The specific experimental steps for preparing the fatty-chain silicone-oxygen alkane type macromolecular amine curing agent are as follows: Under the protection of nitrogen, 3.8 g of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane, 0.5 g of 2,2-dimethoxy-2-phenylacetophenone, and 50 mL of anhydrous tetrahydrofuran are added to a three-necked flask, stirred at room temperature until completely dissolved, and under ultraviolet light irradiation (365 nm, 10 cm), 30 mL of an anhydrous tetrahydrofuran solution containing 3.1 g of 4-mercaptobenzoic acid is added dropwise to the three-necked flask using a constant pressure funnel. After the addition is complete, continue to stir and react for 30 min under ultraviolet light irradiation, rotary evaporate to remove the solvent, wash with deionized water, and dry in vacuo to obtain the dicarboxylic acid monomer; Under the protection of nitrogen, 3.5 g of the dicarboxylic acid monomer, 1.2 g of hexamethylenediamine, and 50 mL of anhydrous tetrahydrofuran are added to a three-necked flask equipped with a water separator, stirred at room temperature until completely dissolved, and then 10 mL of an anhydrous tetrahydrofuran solution containing 0.7 g of triethylamine is added to the three-necked flask. The temperature is raised to 80 °C and stirred under reflux for 10 h, rotary evaporate to remove the solvent, wash with deionized water, and dry in vacuo to obtain the fatty-chain silicone-oxygen alkane type macromolecular amine curing agent; The nuclear magnetic resonance hydrogen spectrum characterization of the fatty-chain silicone-oxygen alkane type macromolecular amine curing agent is as follows: 1 H NMR(CDCl3, 400 MHz) δ: 0.06(s, 12H), 1.07 - 1.11(t, 4H), 1.31 - 1.45(m, 12H), 1.59 - 1.66(m, 4H), 2.63 - 2.66(t, 4H), 2.87 - 2.90(t, 4H), 3.26 - 3.30(t, 4H), 7.28 - 7.82(m, 18H, Ar-H). Experimental Example 2:

[0017] Prepare an aromatic etherified silicone-oxygen alkane type macromolecular amine curing agent: Using the nucleophilic substitution reaction mechanism, the carboxyl functional groups of 1 molar equivalent of dicarboxylic acid monomers and the amino functional groups of 2.08 molar equivalents of 4,4'-diaminodiphenyl ether are catalyzed by an organic base catalyst to undergo an acylation reaction to produce an aromatic etherified silicone-oxygen alkane type macromolecular amine curing agent, and its chemical structural formula is: ; Among them, the organic base catalyst is one of pyridine, triethylamine, tributylamine, and imidazole. In this example, triethylamine is selected for use; The specific experimental steps for preparing the aromatic etherified siloxane-based macromolecular amine curing agent refer to the preparation experiment of the aliphatic chain siloxane-based macromolecular amine curing agent. The only difference is that 2.0 g of 4,4'-diaminodiphenyl ether is used to replace 1.2 g of hexamethylenediamine; The 1H NMR characterization of the aromatic etherified siloxane-based macromolecular amine curing agent is as follows: 1 H NMR(CDCl3, 400 MHz) δ: 0.06(s, 12H), 1.09 - 1.13(t, 4H), 2.86 - 2.90(t, 4H), 6.73 - 7.84(m, 34H, Ar-H). Example 1:

[0018] A waterborne epoxy floor topcoat includes component A and component B; among them, the formulation of component A is shown in Table 1, and the formulation of component B is shown in Table 2; Table 1 Formulation of Component A in Waterborne Epoxy Floor Topcoat

[0019] Table 2 Formulation of Component B in Waterborne Epoxy Floor Topcoat

[0020] Among them, the macromolecular amine curing agent is an aliphatic chain siloxane-based macromolecular amine curing agent or an aromatic etherified siloxane-based macromolecular amine curing agent. Example 2:

[0021] A preparation process of a waterborne epoxy floor topcoat includes the following steps: Step 1, prepare component A: According to the formulation in Table 1, mix the formulated amount of water, BYK-346 wetting agent, FX 600 dispersant, and BYK-011 defoaming agent, stir at a speed of 500 r / min for 10 min, then successively add the formulated amount of CMA-444 talc powder and YX-3000 barium sulfate, raise the speed to 1500 r / min and stir and disperse for 10 min, add zirconium beads (800 g) and grind for 1 h, pass cooling water, then add the formulated amount of 2060H waterborne epoxy resin emulsion, reduce the speed to 1000 r / min and stir for 15 min, keep the speed of 1000 r / min and add the formulated amount of aluminum tripolyphosphate and mica powder, stir and mix for 20 min, finally keep the speed of 1000 r / min and add the formulated amount of bentonite and stir for 5 min, reduce the speed to 300 r / min, defoam at low speed for 30 min, filter through a 100-mesh gauze, and stir evenly to obtain component A of the waterborne epoxy floor topcoat; Step 2: Prepare Component B: According to the formulation in Table 2, mix the formulated amount of macromolecular amine curing agent and water, and stir and dissolve for 30 min at a rotation speed of 100 r / min to obtain Component B of the waterborne epoxy floor paint; Step 3: Mix Component A and Component B evenly in a mass ratio of 4:1 to prepare the waterborne epoxy floor paint; Among them, when the macromolecular amine curing agent is a fatty-chain siloxane-type macromolecular amine curing agent, the prepared product is denoted as waterborne epoxy floor paint I; When the macromolecular amine curing agent is an aromatic etherified siloxane-type macromolecular amine curing agent, the prepared product is denoted as waterborne epoxy floor paint II. Performance test:

[0022] Use a 2 mm trowel to apply the waterborne epoxy floor paint product on the surface of the calcium silicate board by troweling, and control the surface density at 1.0 kg / m 2 , and after curing at room temperature, a waterborne epoxy coating is formed, and the water resistance and corrosion resistance are tested. The results are shown in Table 3; Table 3 Performance test results of waterborne epoxy floor paint I

[0023] Note: The difference between Comparative Example 1 and waterborne epoxy floor paint I is only that: a conventional waterborne epoxy curing agent (commercially available WEH 102 waterborne epoxy curing agent, without organosilicon) is used to replace the fatty-chain siloxane-type macromolecular amine curing agent; the difference between Comparative Example 2 and waterborne epoxy floor paint I is only that: a traditional small-molecule amine curing agent (ethylenediamine) is used to replace the fatty-chain siloxane-type macromolecular amine curing agent; From the experimental results in Table 3, the following conclusions can be drawn: The waterborne epoxy floor paint prepared by the present invention using the self-developed macromolecular amine curing agent has achieved a significantly improved beneficial technical effect in terms of water resistance and corrosion resistance compared with the epoxy coatings using conventional waterborne epoxy curing agents and traditional small-molecule amine curing agents; Among them, the waterborne epoxy floor paint II prepared using the aromatic etherified siloxane-type macromolecular amine curing agent has better water resistance; According to the test methods specified in the standard of GB / T 22374-2018 "Floor Coating Materials", the comprehensive performance of the waterborne epoxy floor paint is tested, and the test results are shown in Table 4 below; Table 4 Performance test results of waterborne epoxy floor paint II

[0024] From the experimental results in Table 4, the following conclusions can be drawn: All the properties of the waterborne epoxy floor topcoat prepared by the present invention meet the technical requirements specified in the standard of GB / T 22374-2018, and it has excellent comprehensive performance and practical application value.

Claims

1. A preparation process of an aqueous epoxy floor topcoat, characterized in that It includes the following steps: Step 1: Prepare a macromolecular amine curing agent, which is a fatty-chain siloxane-type macromolecular amine curing agent or an aromatic-etherified siloxane-type macromolecular amine curing agent; Step 2: Use an aqueous epoxy resin emulsion as the film-forming component and a fatty-chain siloxane-type macromolecular amine curing agent or an aromatic-etherified siloxane-type macromolecular amine curing agent as the crosslinking and curing component to prepare an aqueous epoxy floor topcoat.

2. The preparation process of a waterborne epoxy floor topcoat according to claim 1, characterized in that, The chemical structural formula of the fatty-chain siloxane-type macromolecular amine curing agent is: 。 3. The preparation process of a waterborne epoxy floor topcoat according to claim 2, characterized in that, The preparation method of the fatty-chain siloxane-type macromolecular amine curing agent is: In the presence of a photoinitiator, the alkenyl functional group of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane reacts with the mercapto functional group of 2.01 - 2.09 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light to generate a dicarboxylic acid monomer through a click reaction; Using the mechanism of nucleophilic substitution reaction, the carboxyl functional group of 1 molar equivalent of the dicarboxylic acid monomer and the amino functional group of 2.01 - 2.09 molar equivalents of hexamethylenediamine undergo an acylation reaction catalyzed by an organic basic catalyst to generate a fatty-chain siloxane-type macromolecular amine curing agent.

4. The preparation process of a waterborne epoxy floor topcoat according to claim 3, characterized in that, The photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone.

5. The preparation process of an aqueous epoxy floor topcoat according to claim 1, characterized in that, The chemical structural formula of the aromatic-etherified siloxane-type macromolecular amine curing agent is: 。 6. The preparation process of a waterborne epoxy floor topcoat according to claim 5, characterized in that, The preparation method of the aromatic-etherified siloxane-type macromolecular amine curing agent is: Using the mechanism of nucleophilic substitution reaction, the carboxyl functional group of 1 molar equivalent of the dicarboxylic acid monomer and the amino functional group of 2.01 - 2.09 molar equivalents of 4,4'-diaminodiphenyl ether undergo an acylation reaction catalyzed by an organic basic catalyst to generate an aromatic-etherified siloxane-type macromolecular amine curing agent.

7. The preparation process of a waterborne epoxy floor topcoat according to claim 3 or 6, characterized in that, The organic basic catalyst is one of pyridine, triethylamine, tributylamine, and imidazole.

8. An aqueous epoxy floor topcoat prepared by the process according to any one of claims 1-6, characterized in that, The aqueous epoxy floor topcoat includes component A and component B; The formula of component A is: 10 - 20 parts by weight of water, 5 - 10 parts by weight of talc powder, 10 - 15 parts by weight of barium sulfate, 45 - 55 parts by weight of an aqueous epoxy resin emulsion, 5 - 8 parts by weight of aluminum tripolyphosphate, 5 - 8 parts by weight of mica powder, and 0.5 - 5 parts by weight of a composite auxiliary agent; The formula of component B is: 25 - 30 parts by weight of a macromolecular amine curing agent and 70 - 80 parts by weight of water.

9. The waterborne epoxy floor topcoat according to claim 8, characterized in that The mass ratio of component A to component B in the aqueous epoxy floor topcoat is (3 - 5) :

1.

10. A waterborne epoxy floor topcoat according to claim 8, characterized in that, The composite auxiliary agent includes a wetting agent, a dispersing agent, an antifoaming agent, and a thickening agent.

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