Water-based high-constructability epoxy primer as well as preparation method and application thereof

Abstract

The invention discloses a water-based high-constructability epoxy primer as well as a preparation method and application thereof.The preparation raw materials comprise a component A and a component B, and the weight ratio of the component A to the component B is (5-15): 1; the component A is prepared from the following components in parts by weight: 40 to 50 parts of epoxy emulsion, 0.5 to 3 parts of dispersing agent, 0.1 to 0.2 part of defoaming agent, 15 to 25 parts of toner, 1 to 10 parts of anti-rust pigment, 5 to 15 parts of filler, 0.2 to 0.5 part of anti-sagging aid, 10 to 15 parts of deionized water I, 1 to 2 parts of cosolvent I, 0.1 to 0.2 part of wetting agent, 0.1 to 0.2 part of flatting agent and 0.1 to 0.3 part of thickening agent; the component B comprises the following components in parts by weight: 5-10 parts of a modified amine curing agent, 0.2-0.5 part of a rheological additive, 2-4 parts of a cosolvent II and 1-3 parts of deionized water II. The anti-sagging and salt spray-resistant waterborne epoxy primer realizes the balance of anti-sagging and salt spray-resistant properties, and can meet the use standard of rail transit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating compositions, in particular to a water-based high-build epoxy primer, a preparation method and application thereof. BACKGROUND

[0002] With the improvement of people's environmental awareness, water-based coatings are increasingly used. In the field of rail transit, due to the high requirement for anti-corrosion, the use of water-based coatings is relatively small. It is necessary to develop water-based primers with high corrosion resistance. Water-washing epoxy primer has great application potential in rail transit car body, parts and interior decoration. However, high corrosion resistance primer has high demand for construction window, which increases the difficulty of construction for workers. Therefore, it is important to develop water-based epoxy primer that can adapt to various manual and mechanical spraying methods, and at the same time meet the requirements of corrosion resistance.

[0003] Chinese patent CN118879159B discloses a water-based two-component epoxy primer for rail transit coating and a preparation method thereof. A specific rheological agent and an anti-sagging agent are used in combination. The two-component epoxy primer contains a large amount of powder and particles, has excellent anti-sagging performance, and can adapt to electrostatic spraying. However, the corrosion resistance is not good. Chinese patent CN115595027B discloses a water-based two-component acrylic modified epoxy primer, a preparation method and application thereof. A water-insoluble low-shear polyurethane thickening agent is added to the curing agent B component. The mixed coating maintains a certain viscosity, thereby maintaining good anti-sagging performance. However, the corrosion resistance is not significantly improved. SUMMARY

[0004] In order to develop a water-based epoxy primer that can adapt to various manual and mechanical spraying methods, and at the same time meet the requirements of corrosion resistance, the first aspect of the present application provides a water-based high-build epoxy primer. The preparation raw materials include component A and component B. The weight ratio of the A component and the B component is (5-15):1. In terms of weight parts, the A component includes epoxy emulsion 40-50 parts, dispersing agent 0.5-3 parts, defoaming agent 0.1-0.2 parts, color powder 15-25 parts, anti-rust pigment 1-10 parts, filler 5-15 parts, anti-sagging aid 0.2-0.5 parts, deionized water 10-15 parts, cosolvent 1-2 parts, wetting agent 0.1-0.2 parts, leveling agent 0.1-0.2 parts, and thickening agent 0.1-0.3 parts. The B component includes modified amine curing agent 5-10 parts, rheological aid 0.2-0.5 parts, cosolvent 2-4 parts, and deionized water 1-3 parts.

[0005] As an implementation, the weight ratio of the A component and the B component is 10:1.

[0006] As an embodiment, the anti-sagging aid includes a montmorillonite clay and a lignocellulosic complexing aid.

[0007] As an embodiment, the montmorillonite clay is an organically modified hectorite clay.

[0008] As an embodiment, the lignocellulosic complexing aid is an aid containing 5-15 wt% lignocellulosic aqueous solution.

[0009] As an embodiment, the weight ratio of the montmorillonite clay and the lignocellulosic complexing aid is (0.1-0.3):(0.1-0.3).

[0010] As an embodiment, the weight ratio of the montmorillonite clay and the lignocellulosic complexing aid is 0.2:0.2.

[0011] As an embodiment, the rheological aid is a polyamide wax.

[0012] As an embodiment, the acid value of the rheological aid is 5-10.

[0013] As an embodiment, the anti-rust pigment includes at least one of talc, a phosphate, a molybdate, or a chromate.

[0014] As an embodiment, the phosphate includes at least one of aluminum tripolyphosphate, aluminum zinc phosphomolybdate, zinc phosphate; the molybdate includes at least one of zinc molybdate, aluminum molybdate.

[0015] As an embodiment, the anti-rust pigment is a combination of talc and zinc phosphate / zinc molybdate complex.

[0016] As an embodiment, the weight ratio of the talc and the zinc phosphate / zinc molybdate complex is (2-4):(2-4).

[0017] As an embodiment, the weight ratio of the talc and the zinc phosphate / zinc molybdate complex is 3:3.

[0018] As an embodiment, the dispersant is a polymeric non-ionic wet dispersant.

[0019] As an embodiment, the defoaming agent includes, but is not limited to, a silicone-based defoaming agent.

[0020] As an embodiment, the defoaming agent is a polyether-modified polydimethylsiloxane aqueous defoaming agent.

[0021] As an embodiment, the toner includes at least one of titanium white, red iron oxide, or yellow iron oxide.

[0022] As an implementation form, the color powder is a combination of titanium white powder, red iron oxide and yellow iron oxide.

[0023] As an implementation form, the weight ratio of the titanium white powder, the red iron oxide and the yellow iron oxide is (10-20):(2-4):(1-3).

[0024] As an implementation form, the weight ratio of the titanium white powder, the red iron oxide and the yellow iron oxide is 15:3:2.

[0025] As an implementation form, the filler is barium sulfate.

[0026] As an implementation form, the epoxy emulsion has an epoxy equivalent of 460-630 g / mL, and a dynamic viscosity of 400-4000 mPa·s at 25°C.

[0027] As an implementation form, the co-solvent one and the co-solvent two each include but are not limited to at least one of ethylene glycol monobutyl ether, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol monobutyl ether, an alcohol solvent, and an ester solvent.

[0028] As an implementation form, the co-solvent one and the co-solvent two are both propylene glycol methyl ether.

[0029] As an implementation form, the wetting agent includes but is not limited to a silicone-based wetting agent.

[0030] As an implementation form, the leveling agent includes but is not limited to a polyether siloxane polymer leveling agent.

[0031] As an implementation form, the thickening agent is a non-ionic polyurethane thickening agent.

[0032] As an implementation form, the modified amine curing agent has an active hydrogen equivalent of 100-200 g / mol, and a dynamic viscosity of 4000-11000 mPa·s at 25°C.

[0033] The second aspect of the present application provides a preparation method of an aqueous high-build epoxy primer, including the following steps: Preparation of A component: Deionized water one is added with a dispersing agent and a defoaming agent under a stirring speed of 100-400 r / min, and stirred until mixed uniformly, and then the color powder, the filler, the anti-rust pigment and the anti-sagging agent are added, the stirring speed is increased to 200-500 r / min, and stirred until mixed uniformly, and then ground until the grinding fineness is ≤20 μm; in a stirring state, the epoxy emulsion is added to the ground material, and stirred until mixed uniformly, the stirring speed is adjusted to 300-600 r / min, and then the co-solvent one, the wetting agent, the leveling agent and the thickening agent are added, and stirred until mixed uniformly, to obtain the A component. Preparation of component B: The modified amine curing agent, rheology modifier, cosolvent II, and deionized water II were mixed and stirred until homogeneous to obtain component B. Component A and component B are mixed in a certain mass ratio to obtain a water-based epoxy primer with high workability.

[0034] A third aspect of the present invention provides an application of a water-based, highly workable epoxy primer in rail transit products.

[0035] Compared with the prior art, the present invention has the following beneficial effects: (1) The water-based high workability epoxy primer of the present invention uses a combination of montmorillonite clay and lignocellulose composite additive as an anti-sagging additive, which can improve the workability of the coating and avoid sagging.

[0036] (2) The water-based high workability epoxy primer of the present invention uses a compounded anti-sagging agent combined with a rheology modifier of polyamide wax. After the two components A and B are mixed, the anti-sagging property is improved again, the spraying window is widened, and the construction is convenient for workers.

[0037] (3) The water-based high workability epoxy primer of the present invention uses a combination of talc powder and zinc phosphate / zinc molybdate composite as an anti-rust pigment, which can make up for the problem of reduced salt spray resistance caused by the use of anti-sagging additives and achieve a balance between anti-sagging and salt spray resistance.

[0038] (4) The water-based high-workability epoxy primer of the present invention uses a combination of titanium dioxide, iron oxide red and iron oxide yellow pigments, which can further improve the salt spray resistance of the epoxy primer so that it can meet the standards for use in rail transit.

[0039] (5) The water-based high workability epoxy primer of the present invention can, through the synergistic effect of epoxy emulsion, dispersant, defoamer, cosolvent, wetting agent, leveling agent and thickener, make the anti-sagging agent, color powder and anti-rust pigment dispersed evenly in the primer to form a stable paint film. Detailed Implementation

[0040] Example A water-based epoxy primer with high workability, the raw materials for which are prepared are shown in Table 1-3 below.

[0041] Table 1

[0042] Table 2

[0043] Table 3

[0044] The anti-sagging additive BENTONE LT is an organically modified lithium montmorillonite clay; the additive F01-V is an additive containing 5-15 wt% lignocellulose aqueous solution.

[0045] The rheology modifier Disparon AQH-800 is a polyamide wax with an acid value of 7.5; the Fenghong PA-670 is a polyamide wax with an acid value of 12-13.

[0046] Guangyuan Chemical HS-658 is talc powder, Xinjing APW-2 is aluminum tripolyphosphate, and Nubirox 106 is an organically treated zinc phosphate / zinc molybdate composite.

[0047] The epoxy emulsion Qirun EP137 has an epoxy equivalent of 460-630 g / mL and a dynamic viscosity of 400-4000 mPa·s at 25°C. The modified amine curing agent Qirun EH3504 has an active hydrogen equivalent of 100-200 g / mol and a dynamic viscosity of 4000-11000 mPa·s at 25℃.

[0048] A method for preparing a water-based epoxy primer with high workability includes the following steps: Preparation of component A: Deionized water is stirred at 300 rpm with dispersant and defoamer added until homogeneous. Color powder, filler, rust-preventive pigment, and anti-sagging agent are then added, and the stirring speed is increased to 400 rpm until homogeneous. The mixture is then ground until the fineness is ≤ 20 μm. While stirring, epoxy emulsion is added to the ground material and stirred until homogeneous. The stirring speed is adjusted to 500 rpm, and cosolvent, wetting agent, leveling agent, and thickener are added and stirred until homogeneous to obtain component A. Preparation of component B: The modified amine curing agent, rheology modifier, cosolvent II, and deionized water II were mixed and stirred until homogeneous to obtain component B. Component A and component B are mixed in a certain mass ratio to obtain a water-based epoxy primer with high workability.

[0049] Performance testing 1. Sagging performance test: After mixing components A and B of the example and comparative example, add 5-10 wt% water relative to component A to dilute. Use a capillary viscometer to test the viscosity to reach 40-50 s, so that it meets the viscosity of the construction process, and then apply it.

[0050] Using a 120mm×50mm glass plate, hold the sag meter and press its toothed surface vertically onto the substrate, pulling the coating downwards at a uniform speed to form a continuous wet film ranging from 50μm to 300μm in thickness on the substrate. After 15-20 minutes, observe the upper grid reading where the distance between the two wet films does not change. This is the sag data of the coating. The higher the sag value, the better the anti-sag property.

[0051] 2. Salt spray resistance test: An environmental test that uses artificially simulated salt spray conditions created by salt spray testing equipment to assess the corrosion resistance of products or metallic materials. It is conducted in a salt spray test chamber, which is equipped with a spray system, a heating system, and a control system.

[0052] The epoxy primers used in the examples and comparative examples were sprayed onto the surfaces of a metal plate and a composite material plate, respectively, to form coatings. The coatings were ensured to be completely dry as test panels. The metal plate was an aluminum alloy plate, and the composite material plate was a fiberglass SMC plate.

[0053] A 5wt% sodium chloride solution was used as the salt spray source and added to the spray tower. Spraying time, temperature, humidity, and other parameters were set according to GB / T 1771.

[0054] Place the test plate into the salt spray chamber and start the spray system to ensure the salt spray fully covers the sample surface. During the test, periodically observe the corrosion on the sample surface and record the time when corrosion occurs.

[0055] The test results are shown in Table 4.

[0056] Table 4

[0057] The comparative test results show that Example 10 meets the requirements and has the best effect.

Claims

1. A water-based epoxy primer with high workability, characterized in that, The raw materials for preparation include component A and component B, wherein the weight ratio of component A to component B is (5-15):1; By weight: Component A comprises 40-50 parts epoxy emulsion, 0.5-3 parts dispersant, 0.1-0.2 parts defoamer, 15-25 parts color powder, 1-10 parts anti-rust pigment, 5-15 parts filler, 0.2-0.5 parts anti-sagging agent, 10-15 parts deionized water, 1-2 parts cosolvent, 0.1-0.2 parts wetting agent, 0.1-0.2 parts leveling agent, and 0.1-0.3 parts thickener; Component B comprises 5-10 parts modified amine curing agent, 0.2-0.5 parts rheology modifier, 2-4 parts cosolvent, and 1-3 parts deionized water.

2. The water-based, highly workable epoxy primer according to claim 1, characterized in that, The anti-sagging additive includes a composite additive of montmorillonite clay and lignocellulose.

3. The water-based, highly workable epoxy primer according to claim 2, characterized in that, The montmorillonite clay is an organically modified lithium montmorillonite clay.

4. The water-based, highly workable epoxy primer according to claim 2, characterized in that, The lignocellulose composite additive is an additive containing 5-15 wt% lignocellulose aqueous solution.

5. The water-based, highly workable epoxy primer according to claim 1, characterized in that, The rheology modifier is a polyamide wax.

6. The water-based, highly workable epoxy primer according to claim 5, characterized in that, The rheology modifier has an acid value of 5-10.

7. The water-based, highly workable epoxy primer according to claim 1, characterized in that, The rust-preventive pigment includes at least one of talc, phosphate, molybdate, or chromate.

8. The water-based, highly workable epoxy primer according to claim 7, characterized in that, The phosphate includes at least one of aluminum tripolyphosphate, zinc aluminum phosphomolybdate, and zinc phosphate; the molybdate includes at least one of zinc molybdate and aluminum molybdate.

9. A method for preparing a water-based, highly workable epoxy primer according to any one of claims 1-8, characterized in that, Includes the following steps: Preparation of component A: Add dispersant and defoamer to deionized water at a stirring speed of 100-400 r / min, stir until uniformly mixed, add color powder, filler, rust-preventive pigment and anti-sagging agent, increase the stirring speed to 200-500 r / min, stir until uniformly mixed, grind until the fineness is ≤ 20μm; Under stirring, add epoxy emulsion to the ground material and stir until uniformly mixed. Adjust the stirring speed to 300-600 r / min, add cosolvent one, wetting agent, leveling agent and thickener, and stir until uniformly mixed to obtain component A. Preparation of component B: The modified amine curing agent, rheology modifier, cosolvent II, and deionized water II were mixed and stirred until homogeneous to obtain component B. Component A and component B are mixed in a certain mass ratio to obtain a water-based epoxy primer with high workability.

10. An application of the water-based, highly workable epoxy primer according to any one of claims 1-8, characterized in that, It is used in rail transit products.

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