A waterborne epoxy floor finish and its preparation process

Abstract

The present invention relates to the technical field of floor coatings and discloses a waterborne epoxy floor topcoat and a preparation process thereof. The method comprises the following steps: designing and synthesizing a macromolecular amine curing agent based on a click reaction mechanism of a mercapto-alkenyl group and an acylation reaction mechanism of an amino-carboxyl group, wherein the macromolecular amine curing agent is a fatty chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent; and using a waterborne epoxy resin emulsion as a film-forming component and the fatty chain siloxane type macromolecular amine curing agent or the aromatic etherified siloxane type macromolecular amine curing agent as a cross-linking and curing component to prepare the waterborne epoxy floor topcoat. The waterborne epoxy floor topcoat has excellent water resistance and corrosion resistance, and various properties meet the technical requirements specified in the GB / T 22374-2018 standard, has relatively good comprehensive performance, and has practical value.

Description

Technical Field

[0001] The present invention relates to the technical field of floor coatings, in particular to a water-based epoxy floor finish and a preparation process thereof. Background Art

[0002] Epoxy resin coatings, characterized by their relatively low cost, excellent abrasion resistance, and strong adhesion, are widely used as floor topcoats in industrial floor coatings. With increasing environmental awareness, epoxy floor coatings are gradually evolving from traditional solvent-based coatings with high VOC content to low-toxic, non-toxic, and environmentally friendly water-based coatings. Water-based epoxy coatings use water as a dispersion medium, offering safe and reliable storage, transportation, and application, and excellent workability. With their enormous potential, significance, and application prospects, they have become the preferred choice in the floor coating market.

[0003] Curing agents play a key role in achieving a uniform, stable, and smooth coating for waterborne epoxy coatings. Amines are the most commonly used curing agents in waterborne epoxy coatings. Traditional small-molecule amine curing agents generally suffer from shortcomings such as excessive reactivity, short pot life, high toxicity, and volatility, which can lead to undesirable phenomena such as holes in the epoxy resin coating surface. Therefore, traditional small-molecule amine curing agents often need to be modified to meet actual application requirements. Amine-modified waterborne epoxy curing agents can be mainly divided into three categories: amidated polyamines, polyamides, and polyamine-epoxy resin complexes.

[0004] Water-based epoxy curing agent uses water as solvent. Compared with organic solvents, water has higher heat of evaporation and surface tension, which makes the film-forming and drying time of water-based epoxy curing agent longer and its wetting and dispersion properties poor. 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. Therefore, the water-based epoxy curing agent needs to be modified. Common modification methods include silicone modification, polyurethane modification and Mannich amine modification. The Si-O bond in silicone is very 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 develops a macromolecular amine curing agent to replace the existing commercial small-molecule amine curing agent. The macromolecular amine curing agent is used as a curing agent to promote the curing and cross-linking of water-based epoxy resin to prepare a water-based epoxy floor topcoat, which has excellent water resistance and corrosion resistance and meets the technical requirements specified in the GB / T 22374-2018 "Floor Coating Materials" standard.

[0006] A preparation process of a water-based epoxy floor finish comprises the following steps:

[0007] Step 1: preparing a macromolecular amine curing agent, wherein the macromolecular amine curing agent is a fatty chain siloxane type macromolecular amine curing agent or an aromatic ether siloxane type macromolecular amine curing agent;

[0008] Step 2: Prepare a water-based epoxy floor topcoat using a water-based epoxy resin emulsion as a film-forming component and a fatty chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent as a cross-linking curing component.

[0009] Preferably, the preparation method of the fatty chain siloxane type macromolecular amine curing agent is:

[0010] In the presence of a photoinitiator, a click reaction occurs between the alkenyl functional group of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane and the mercapto functional group of 2.01-2.09 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light to generate a dicarboxyl monomer;

[0011] By utilizing the nucleophilic substitution reaction mechanism, an organic alkaline catalyst is used to catalyze the acylation reaction between the carboxyl functional group of 1 molar equivalent of dicarboxyl monomer and the amino functional group of 2.01-2.09 molar equivalents of hexamethylenediamine to generate a fatty chain siloxane type macromolecular amine curing agent.

[0012] Preferably, the photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone.

[0013] Preferably, the preparation method of the aromatic etherified siloxane type macromolecular amine curing agent is: utilizing a nucleophilic substitution reaction mechanism, catalyzing an acylation reaction between 1 molar equivalent of the carboxyl functional group of a dicarboxyl monomer and 2.01-2.09 molar equivalents of the amino functional group of 4,4'-diaminodiphenyl ether by an organic alkaline catalyst, to generate an aromatic etherified siloxane type macromolecular amine curing agent.

[0014] Preferably, the organic alkaline catalyst is one of pyridine, triethylamine, tributylamine and imidazole.

[0015] A waterborne epoxy floor finish prepared according to the above process comprises component A and component B;

[0016] The formula of the component A is: 10-20 parts by weight of water, 5-10 parts by weight of talc, 10-15 parts by weight of barium sulfate, 45-55 parts by weight of water-based 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 composite additives;

[0017] The formula of the B component is: 25-30 parts by weight of a macromolecular amine curing agent and 70-80 parts by weight of water.

[0018] Preferably, the mass ratio of component A to component B in the waterborne epoxy floor finish is (3-5):1.

[0019] Preferably, the composite auxiliary agent includes a wetting agent, a dispersant, a defoaming agent and a thickener. Beneficial effects

[0020] Based on the thiol-alkenyl click reaction mechanism and the amino-carboxyl acylation reaction mechanism, the present invention designed and synthesized two macromolecular amine curing agents (fatty chain siloxane type macromolecular amine curing agent and aromatic etherified siloxane type macromolecular amine curing agent);

[0021] A water-based epoxy floor topcoat is prepared by using a fatty chain siloxane-type macromolecular amine curing agent or an aromatic etherified siloxane-type macromolecular amine curing agent as a cross-linking and curing component of a water-based epoxy resin emulsion. Performance test results show that the water-based epoxy floor topcoat prepared by the present invention has excellent water resistance and corrosion resistance, and all performances meet the technical requirements specified in GB / T 22374-2018 standard. It has excellent comprehensive performance and practical value. DETAILED DESCRIPTION

[0022] The present invention designs and synthesizes two macromolecular amine curing agents. On the one hand, their molecular structures simultaneously contain hydrophilic amino and amide groups and hydrophobic alkyl carbon chains and aromatic rings, and are typical amphiphilic surfactants with certain emulsification, water dispersibility, and low toxicity. On the other hand, their molecular structures also contain organic silicon structures. The Si-O bonds in the organic silicon structures have strong polarity and can significantly enhance the water resistance and corrosion resistance of epoxy resins. Thirdly, the benzene ring structure contained in their molecular structures can increase their compatibility with epoxy resins.

[0023] Experimental Example 1:

[0024] Preparation of fatty chain siloxane type macromolecular amine curing agent, the preparation method is as follows:

[0025] Step 1: In the presence of a photoinitiator, a click reaction occurs between the alkenyl functional group of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane and the mercapto functional group of 2.05 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light to generate a dicarboxyl monomer, the chemical structure of which is:

[0026] ;

[0027] The photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylacetone, and 2,2-diethoxyacetophenone; 2,2-dimethoxy-2-phenylacetophenone is selected in this embodiment;

[0028] Step 2: Using the nucleophilic substitution reaction mechanism, an organic alkaline catalyst is used to catalyze the acylation reaction between the carboxyl functional group of 1 molar equivalent of dicarboxyl monomer and the amino functional group of 2.08 molar equivalents of hexamethylenediamine to generate a fatty chain siloxane type macromolecular amine curing agent, the chemical structure of which is:

[0029] ;

[0030] The organic alkaline catalyst is one of pyridine, triethylamine, tributylamine, and imidazole. In this embodiment, triethylamine is used.

[0031] The specific experimental steps for preparing the fatty chain siloxane type macromolecular amine curing agent are as follows:

[0032] Under nitrogen protection, 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 were added to a three-necked flask and stirred at room temperature until completely dissolved. Under ultraviolet light irradiation (365 nm, 10 cm), 30 mL of anhydrous tetrahydrofuran solution containing 3.1 g of 4-mercaptobenzoic acid was added dropwise to the three-necked flask using a constant pressure funnel. After the addition was complete, stirring and reacting were continued under ultraviolet light for 30 minutes. The solvent was removed by rotary evaporation, and the mixture was washed with deionized water and dried in vacuo to obtain a dicarboxyl monomer.

[0033] Under nitrogen protection, 3.5 g of dicarboxyl monomer, 1.2 g of hexamethylenediamine and 50 mL of anhydrous tetrahydrofuran were added to a three-necked flask with a water separator and stirred at room temperature until completely dissolved. Then, 10 mL of anhydrous tetrahydrofuran solution containing 0.7 g of triethylamine was added to the three-necked flask, and the temperature was raised to 80° C. and stirred under reflux for 10 h. The solvent was removed by rotary evaporation, and the mixture was washed with deionized water and dried in vacuo to obtain a fatty chain siloxane type macromolecular amine curing agent.

[0034] The nuclear magnetic resonance hydrogen spectrum of the fatty chain siloxane type macromolecular amine curing agent is characterized as follows: 1 H NMR (CDCl3, 400MHz) δ: 0.06 (s, 12H), 1.07-1.11 (t, 4H), 1.31-1.45 (m, 12H), 1.59-1.66 (m, 4H), 2.6 3-2.66(t, 4H), 2.87-2.90(t, 4H), 3.26-3.30(t, 4H), 7.28-7.82(m, 18H, Ar-H).

[0035] Experimental Example 2:

[0036] Preparation of aromatic etherified siloxane macromolecular amine curing agent: Using the nucleophilic substitution reaction mechanism, an organic alkaline catalyst is used to catalyze the acylation reaction of the carboxyl functional group of 1 molar equivalent of dicarboxyl monomer and the amino functional group of 2.08 molar equivalents of 4,4'-diaminodiphenyl ether to produce an aromatic etherified siloxane macromolecular amine curing agent, whose chemical structure is:

[0037] ;

[0038] The organic alkaline catalyst is one of pyridine, triethylamine, tributylamine, and imidazole. In this embodiment, triethylamine is used.

[0039] The specific experimental steps for preparing the aromatic etherified siloxane type macromolecular amine curing agent refer to the preparation experiment of the fatty chain siloxane type macromolecular amine curing agent, with the only difference being that 2.0g of 4,4'-diaminodiphenyl ether is used to replace 1.2g of hexamethylenediamine;

[0040] The nuclear magnetic resonance hydrogen spectrum of the aromatic etherified siloxane type macromolecular amine curing agent is characterized as follows: 1 H NMR (CDCl3, 400MHz) 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:

[0041] A water-based epoxy floor finish, comprising component A and component B; wherein the formula of component A is shown in Table 1, and the formula of component B is shown in Table 2;

[0042] Table 1 Formula of component A in waterborne epoxy floor paint

[0043]

[0044] Table 2 Formula of component B in waterborne epoxy floor paint

[0045]

[0046] The macromolecular amine curing agent is a fatty chain siloxane type macromolecular amine curing agent or an aromatic ether siloxane type macromolecular amine curing agent. Example 2:

[0047] A preparation process of a water-based epoxy floor finish comprises the following steps:

[0048] Step 1, prepare component A: according to the formula in Table 1, mix the formulated amount of water, BYK-346 wetting agent, FX 600 dispersant and BYK-011 defoamer, stir at 500 r / min for 10 minutes, then add the formulated amount of CMA-444 talc powder and YX-3000 barium sulfate in sequence, increase the speed to 1500 r / min and stir and disperse for 10 minutes, add zirconium beads (800g) and grind for 1 hour, pass cooling water, then add the formulated amount of 2060H water-based epoxy resin emulsion, reduce the speed to 1000 r / min and stir for 15 minutes, maintain the speed of 1000 r / min and add the formulated amount of aluminum tripolyphosphate and mica powder, stir and mix for 20 minutes, finally maintain the speed of 1000 r / min and add the formulated amount of bentonite and stir for 5 minutes, reduce the speed to 300 r / min, defoam at low speed for 30 minutes, filter through 100 mesh gauze, and stir evenly to obtain component A of the water-based epoxy floor paint;

[0049] Step 2: Prepare component B: According to the formula in Table 2, mix the macromolecular amine curing agent and water, and stir and dissolve at a speed of 100 r / min for 30 minutes to obtain component B of the water-based epoxy floor finish;

[0050] Step 3: Mix component A and component B in a mass ratio of 4:1 to prepare a water-based epoxy floor finish;

[0051] Among them, when the macromolecular amine curing agent is a fatty chain siloxane type macromolecular amine curing agent, the prepared product is recorded as water-based epoxy floor topcoat I;

[0052] When the macromolecular amine curing agent is an aromatic etherified siloxane-type macromolecular amine curing agent, the prepared product is recorded as water-based epoxy floor topcoat II.

[0053] Performance testing:

[0054] Use a 2mm trowel to apply the water-based epoxy floor finish product on the surface of the calcium silicate board by trowel coating, and control the surface density at 1.0kg / m 2 After the room temperature curing is completed, a water-based epoxy coating is formed, and the water resistance and corrosion resistance tests are carried out. The results are shown in Table 3;

[0055] Table 3 Performance test results of waterborne epoxy floor paint

[0056]

[0057] Note: The only difference between Comparative Example 1 and Waterborne Epoxy Floor Topcoat I is that conventional waterborne epoxy curing agent (commercially available WEH 102 waterborne epoxy curing agent, without silicone) is used instead of fatty chain siloxane type macromolecular amine curing agent; the only difference between Comparative Example 2 and Waterborne Epoxy Floor Topcoat I is that traditional small molecule amine curing agent (ethylenediamine) is used instead of fatty chain siloxane type macromolecular amine curing agent;

[0058] The following conclusions can be drawn from the experimental results in Table 3:

[0059] The waterborne epoxy floor topcoat prepared by the present invention using the independently developed macromolecular amine curing agent has achieved the beneficial technical effect of significantly improving water resistance and corrosion resistance compared to epoxy coatings using conventional waterborne epoxy curing agents and traditional small molecule amine curing agents;

[0060] Among them, the water-based epoxy floor topcoat II prepared with aromatic etherified siloxane-type macromolecular amine curing agent has better water resistance;

[0061] The comprehensive performance of waterborne epoxy floor paint was tested according to the test method specified in GB / T 22374-2018 "Floor Coating Materials". The test results are shown in Table 4 below;

[0062] Table 4 Performance test results of waterborne epoxy floor paint II

[0063]

[0064] The following conclusions can be drawn from the experimental results in Table 4:

[0065] The various properties of the waterborne epoxy floor paint prepared by the present invention meet the technical requirements specified in the GB / T 22374-2018 standard, and the comprehensive performance is relatively good, and it has practical application value.

Claims

1. A preparation process for a waterborne epoxy floor finish, characterized in that: The following steps are involved: Step 1: preparing a macromolecular amine curing agent, wherein the macromolecular amine curing agent is a fatty chain siloxane type macromolecular amine curing agent or an aromatic ether siloxane type macromolecular amine curing agent; Step 2: using water-based epoxy resin emulsion as a film-forming component and a fatty chain siloxane type macromolecular amine curing agent or an aromatic etherified siloxane type macromolecular amine curing agent as a cross-linking curing component to prepare a water-based epoxy floor topcoat; The chemical structural formula of the fatty chain siloxane type macromolecular amine curing agent is: ； The chemical structural formula of the aromatic etherified siloxane type macromolecular amine curing agent is: 。 2. The preparation process of a waterborne epoxy floor finish according to claim 1, wherein: The preparation method of the fatty chain siloxane type macromolecular amine curing agent is: In the presence of a photoinitiator, a click reaction occurs between the alkenyl functional group of 1 molar equivalent of 1,5-divinyl-3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane and the mercapto functional group of 2.01-2.09 molar equivalents of 4-mercaptobenzoic acid under the action of ultraviolet light to generate a dicarboxyl monomer; By utilizing the nucleophilic substitution reaction mechanism, an organic alkaline catalyst is used to catalyze the acylation reaction between the carboxyl functional group of 1 molar equivalent of dicarboxyl monomer and the amino functional group of 2.01-2.09 molar equivalents of hexamethylenediamine to generate a fatty chain siloxane type macromolecular amine curing agent.

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

4. A preparation process for a waterborne epoxy floor finish according to claim 2, characterized in that, The preparation method of the aromatic etherified siloxane-type macromolecular amine curing agent comprises: utilizing a nucleophilic substitution reaction mechanism to catalyze an acylation reaction between the carboxyl functional group of 1 molar equivalent of a dicarboxyl monomer and the amino functional group of 2.01-2.09 molar equivalents of 4,4'-diaminodiphenyl ether using an organic alkaline catalyst to generate an aromatic etherified siloxane-type macromolecular amine curing agent.

5. The preparation process of a water-based epoxy floor finish according to claim 2 or 4, wherein: The organic alkaline catalyst is one of pyridine, triethylamine, tributylamine and imidazole.

6. A waterborne epoxy floor finish prepared by the process according to any one of claims 1 to 4, characterized in that: The waterborne epoxy floor finish paint comprises component A and component B; The formula of the component A is: 10-20 parts by weight of water, 5-10 parts by weight of talc, 10-15 parts by weight of barium sulfate, 45-55 parts by weight of water-based 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 composite additives; The formula of the B component is: 25-30 parts by weight of a macromolecular amine curing agent and 70-80 parts by weight of water.

7. A waterborne epoxy floor finish according to claim 6, characterized in that: The mass ratio of component A to component B in the waterborne epoxy floor finish is (3-5):

1.

8. A waterborne epoxy floor finish according to claim 6, characterized in that: The composite auxiliary agent includes a wetting agent, a dispersant, a defoaming agent and a thickener.

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