High-solid-content low-VOC (volatile organic compound) water-based bi-component heavy-duty anticorrosive primer and preparation method thereof

Abstract

The invention discloses a high-solid-content low-VOC (volatile organic compound) water-based bi-component heavy-duty anticorrosive primer and a preparation method thereof, and belongs to the technical field of heavy-duty anticorrosive coatings. The water-based paint is prepared from the following raw materials in parts by weight: 25-45 parts of self-emulsifying water-based epoxy resin, 25-45 parts of a surface modified pigment and filler system, 3-10 parts of a functional aid, 18-35 parts of a polyether amine-acylamino modified water-based epoxy curing agent and 18-35 parts of deionized water, through self-emulsifying resin system construction, pigment and filler interface modification and curing process optimization, the water-based double-component heavy anti-corrosion primer which is remarkably improved in solid content, environmental protection property, anti-corrosion property and construction efficiency is provided, the bottleneck of a traditional heavy anti-corrosion coating is broken through, and the efficient anti-corrosion effect is achieved.

Description

Technical Field

[0001] This invention belongs to the field of heavy-duty anti-corrosion coating technology, and particularly relates to a high-solids-content, low-VOC waterborne two-component heavy-duty anti-corrosion primer and its preparation method. Background Technology

[0002] In the field of industrial corrosion protection, solvent-based heavy-duty anti-corrosion primers have long dominated the market due to their excellent film-forming properties and anti-corrosion effects. However, their solvent systems contain a large amount of volatile organic compounds (VOCs), with typical products having a VOC content exceeding 300g / L, which seriously pollutes the environment and endangers the health of construction workers.

[0003] Existing water-based heavy-duty anti-corrosion primers suffer from the following core technological bottlenecks:

[0004] Low solid content: This results in insufficient film thickness in a single application, requiring multiple coats to achieve an effective anti-corrosion film thickness, leading to low construction efficiency and high energy consumption.

[0005] Insufficient corrosion resistance: Traditional water-based resins rely on added emulsifiers, which easily form defects in the paint film, have poor dispersion stability of pigments and fillers, and have low corrosion resistance time in salt spray tests;

[0006] Incomplete curing: The water-based curing agent has poor compatibility with the resin and low crosslinking density, resulting in poor solvent resistance and mechanical properties of the paint film. Summary of the Invention

[0007] The purpose of this invention is to provide a high-solids-content, low-VOC waterborne two-component heavy-duty anti-corrosion primer and its preparation method in order to solve the above-mentioned problems.

[0008] On the one hand, in order to achieve the above objectives, the present invention adopts the following technical solution: a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer, which is composed of the following raw materials in parts by weight: 25-45 parts of self-emulsifying waterborne epoxy resin, 25-45 parts of surface-modified pigment and filler system, 3-10 parts of functional additives, 18-35 parts of polyetheramine-amide-modified waterborne epoxy curing agent, and 18-35 parts of deionized water.

[0009] As a further description of the above technical solution:

[0010] The self-emulsifying waterborne epoxy resin is an epoxy-amine adduct containing hydroxyl-terminated polyether segments, wherein the epoxy equivalent is 350-550 g / eq, the particle size is 0.05-0.4 μm, and the emulsifier content is ≤2%.

[0011] As a further description of the above technical solution:

[0012] The surface-modified pigment and filler system is composed of the following raw materials in parts by weight: 12-22 parts of zinc phosphate modified with silane coupling agent KH550, 8-15 parts of flaky sericite powder, and 5-10 parts of nano barium sulfate.

[0013] As a further description of the above technical solution:

[0014] The silane coupling agent KH550 modified zinc phosphate has a modifier loading of 1.5%-3% and an oil absorption of ≤35mL / 100g; the flaky sericite powder has an aspect ratio ≥80 and is treated with a titanate coupling agent; the nano barium sulfate has a particle size ≤100nm and its surface is modified with stearic acid.

[0015] As a further description of the above technical solution:

[0016] The functional additive is composed of the following raw materials in parts by weight: 1-3 parts of polycarboxylate dispersant, 0.5-2 parts of organosilicon-polyether block defoamer, 0.5-2 parts of fluorocarbon modified leveling agent, and 2-5 parts of film-forming aid.

[0017] As a further description of the above technical solution:

[0018] The polycarboxylate dispersant has a molecular weight of 5000-10000; the film-forming aid is a compound of propylene glycol phenyl ether and dipropylene glycol methyl ether in a 1:1 ratio.

[0019] As a further description of the above technical solution:

[0020] The polyetheramine-amide modified waterborne epoxy curing agent has an amine value of 350-550 mgKOH / g, an active hydrogen equivalent of 120-200 g / mol, and contains polyethylene glycol segments with a molecular weight of 800-1500.

[0021] On the other hand, in order to achieve the above objectives, the present invention employs the following method: a method for preparing a high-solids-content, low-VOC waterborne two-component heavy-duty anti-corrosion primer, characterized by comprising the following steps:

[0022] 1) Raw material grouping: self-emulsifying waterborne epoxy resin, surface modified pigment and filler system, functional additives and some deionized water are added to group A, and polyetheramine-amide modified waterborne epoxy curing agent and the remaining deionized water are added to group B.

[0023] 2) Pre-dispersion of Group A: Under stirring at 300-600 r / min, add deionized water, polycarboxylate dispersant, silicone-polyether block defoamer, and fluorocarbon modified leveling agent to the dispersion tank, and stir for 15-25 min until the additives are completely dissolved;

[0024] 3) Group A resin dispersion: Slowly add self-emulsifying waterborne epoxy resin at a speed of 500-900 r / min, and maintain stirring for 20-30 min to form a stable oil-in-water dispersion system, at which point the particle size distribution D90≤0.6μm;

[0025] 4) Grinding of pigments and fillers in group A: Increase the rotation speed to 1500-2000 r / min, add silane coupling agent KH550 modified zinc phosphate, flake sericite powder and nano barium sulfate in sequence, disperse at high speed for 30-40 min, then transfer to a sand mill for grinding until the fineness is ≤25μm;

[0026] 5) Preparation of film-forming aids for component A: Add film-forming aids and stir at a low speed of 200-400 r / min for 10-15 min to obtain the finished product of component A;

[0027] 6) Dispersion of component B: Mix the polyetheramine-amide modified waterborne epoxy curing agent with deionized water at 200-500 r / min for 15-20 min until a uniform and transparent solution is formed to obtain the finished product of component B;

[0028] 7) The finished products of component A and component B are packaged separately to obtain a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer.

[0029] As a further description of the above technical solution:

[0030] In step 4), the diameter of the zirconia beads added to the sand mill is 0.5-1.0 mm, and the grinding pressure is 0.4-0.7 MPa.

[0031] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0032] 1. In this invention, a water-based two-component heavy-duty anti-corrosion primer is provided by constructing a self-emulsifying resin system, modifying the interface of pigments and fillers, and optimizing the curing process. This primer significantly improves the solid content, environmental friendliness, anti-corrosion performance, and construction efficiency, breaking through the bottleneck of traditional heavy-duty anti-corrosion coatings and achieving a highly efficient anti-corrosion effect.

[0033] 2. In this invention, by using an internally emulsified epoxy resin and introducing hydrophilic groups into the hydroxyl-terminated polyether segments, self-emulsification is achieved, avoiding the membrane pore defects caused by traditional external emulsifiers.

[0034] 3. In this invention, by adopting a three-stage grinding process of high-speed dispersion and sand milling, the fineness of pigments and fillers is controlled to ≤25μm, which significantly improves the dispersion stability and avoids problems such as stratification and flocculation during construction. Attached Figure Description

[0035] Figure 1 This is a flowchart of a method for preparing a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. 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. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the embodiments of this invention, it should be noted that the terms "upper," "inner," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Example 1:

[0038] S01: Raw material grouping: 35 parts of self-emulsifying waterborne epoxy resin, 38 parts of surface-modified pigment and filler system, 7 parts of functional additives and 15 parts of deionized water are added to group A, and 25 parts of polyetheramine-amide modified waterborne epoxy curing agent and 12 parts of deionized water are added to group B.

[0039] Among them, the self-emulsifying waterborne epoxy resin is an epoxy-amine adduct containing hydroxyl-terminated polyether segments, wherein the epoxy equivalent is 350-550 g / eq, the particle size is 0.05-0.4 μm, and the emulsifier content is ≤2%.

[0040] S02: Group A pre-dispersion: Under stirring at 400 r / min, add 15 parts deionized water, 2 parts polycarboxylate dispersant, 1 part silicone-polyether block defoamer, and 1 part fluorocarbon modified leveling agent to the dispersion tank, and stir for 20 min until the additives are completely dissolved.

[0041] The polycarboxylate dispersant has a molecular weight of 5000-10000; the film-forming aid is a mixture of propylene glycol phenyl ether and dipropylene glycol methyl ether in a 1:1 ratio.

[0042] S03: Group A resin dispersion: Self-emulsifying waterborne epoxy resin was slowly added at a speed of 600 r / min and stirred for 25 min to form a stable oil-in-water dispersion system. At this time, the particle size distribution D90 ≤ 0.6 μm.

[0043] S04: Grinding of pigments and fillers in group A: Increase the rotation speed to 1500 r / min, add 18 parts of silane coupling agent KH550 modified zinc phosphate, 12 parts of flake sericite powder and 8 parts of nano barium sulfate in sequence, disperse at high speed for 35 min, then transfer to a sand mill for grinding until the fineness is ≤25μm;

[0044] The zinc phosphate modified by the silane coupling agent KH550 has a modifier loading of 1.5%-3% and an oil absorption of ≤35mL / 100g; the flaky sericite powder has an aspect ratio ≥80 and is treated with a titanate coupling agent; the nano barium sulfate has a particle size ≤100nm and its surface is modified with stearic acid.

[0045] S05: Preparation of membrane aids for component A: Add 3 parts of film-forming aids and stir at a low speed of 300r / min for 15min to obtain the finished product of component A. The solid content at this time is 65% and the VOC is 42g / L.

[0046] S06: Group B Dispersion: Mix 25 parts of polyetheramine-amide modified waterborne epoxy curing agent with 12 parts of deionized water at 300 r / min for 15 min until a uniform and transparent solution is formed to obtain the finished product of Group B;

[0047] The polyetheramine-amide modified waterborne epoxy curing agent has an amine value of 350-550 mgKOH / g, an active hydrogen equivalent of 120-200 g / mol, and contains polyethylene glycol segments with a molecular weight of 800-1500.

[0048] S07: After the finished products of component A and component B are packaged separately, a high-solids-content, low-VOC waterborne two-component heavy-duty anti-corrosion primer is prepared.

[0049] In practical use, mix the finished product of component A by weight in a ratio of 2-3:1, and apply it by high-pressure airless spraying at a pressure of 0.4-0.6MPa. The wet film thickness of a single coating is 80-120μm, and the corresponding dry film thickness is 50-70μm.

[0050] Example 2:

[0051] S01: Raw material grouping: 45 parts of self-emulsifying waterborne epoxy resin, 42 parts of surface-modified pigment and filler system, 7 parts of functional additives and 10 parts of deionized water are added to group A, and 25 parts of polyetheramine-amide modified waterborne epoxy curing agent and 12 parts of deionized water are added to group B.

[0052] Among them, the self-emulsifying waterborne epoxy resin is an epoxy-amine adduct containing hydroxyl-terminated polyether segments, wherein the epoxy equivalent is 350-550 g / eq, the particle size is 0.05-0.4 μm, and the emulsifier content is ≤2%.

[0053] S02: Group A pre-dispersion: Under stirring at 500 r / min, add 10 parts deionized water, 2 parts polycarboxylate dispersant, 1 part silicone-polyether block defoamer, and 1 part fluorocarbon modified leveling agent to the dispersion tank, and stir for 18 min until the additives are completely dissolved.

[0054] The polycarboxylate dispersant has a molecular weight of 5000-10000; the film-forming aid is a mixture of propylene glycol phenyl ether and dipropylene glycol methyl ether in a 1:1 ratio.

[0055] S03: Group A resin dispersion: Self-emulsifying waterborne epoxy resin was slowly added at a speed of 800 r / min and stirred for 23 min to form a stable oil-in-water dispersion system. At this time, the particle size distribution D90 ≤ 0.6 μm.

[0056] S04: Grinding of pigments and fillers in group A: Increase the rotation speed to 1900 r / min, add 22 parts of silane coupling agent KH550 modified zinc phosphate, 12 parts of flake sericite powder and 8 parts of nano barium sulfate in sequence, disperse at high speed for 32 min, then transfer to a sand mill for grinding until the fineness is ≤25μm;

[0057] The zinc phosphate modified by the silane coupling agent KH550 has a modifier loading of 1.5%-3% and an oil absorption of ≤35mL / 100g; the flaky sericite powder has an aspect ratio ≥80 and is treated with a titanate coupling agent; the nano barium sulfate has a particle size ≤100nm and its surface is modified with stearic acid.

[0058] S05: Preparation of membrane-forming aids for component A: Add 3 parts of membrane-forming aids and stir at a low speed of 350 r / min for 12 min to obtain the finished product of component A. The solid content at this time is 70% and the VOC is 38 g / L.

[0059] S06: Group B Dispersion: 25 parts of polyetheramine-amide modified waterborne epoxy curing agent and 12 parts of deionized water are stirred and mixed at 400 r / min for 18 min until a uniform and transparent solution is formed to obtain the finished product of Group B;

[0060] The polyetheramine-amide modified waterborne epoxy curing agent has an amine value of 350-550 mgKOH / g, an active hydrogen equivalent of 120-200 g / mol, and contains polyethylene glycol segments with a molecular weight of 800-1500.

[0061] S07: After the finished products of component A and component B are packaged separately, a high-solids-content, low-VOC waterborne two-component heavy-duty anti-corrosion primer is prepared.

[0062] In practical use, mix the finished product of component A by weight in a ratio of 2-3:1, and apply it by high-pressure airless spraying at a pressure of 0.4-0.6MPa. The wet film thickness of a single coating is 80-120μm, and the corresponding dry film thickness is 50-70μm.

[0063] Comparative example:

[0064] Purchase a primer from the market. Its characteristics are tested as follows: solid content 48%, VOC 85g / L, single film thickness 25μm, salt spray test 800h scratch corrosion 5mm, and 4 coats are required to achieve a film thickness of 100μm.

[0065] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0066] 1. In this invention, a water-based two-component heavy-duty anti-corrosion primer is provided by constructing a self-emulsifying resin system, modifying the interface of pigments and fillers, and optimizing the curing process. This primer significantly improves the solid content, environmental friendliness, anti-corrosion performance, and construction efficiency, breaking through the bottleneck of traditional heavy-duty anti-corrosion coatings and achieving a highly efficient anti-corrosion effect.

[0067] 2. In this invention, by using an internally emulsified epoxy resin and introducing hydrophilic groups into the hydroxyl-terminated polyether segments, self-emulsification is achieved, avoiding the membrane pore defects caused by traditional external emulsifiers.

[0068] 3. In this invention, by adopting a three-stage grinding process of high-speed dispersion and sand milling, the fineness of pigments and fillers is controlled to ≤25μm, which significantly improves the dispersion stability and avoids problems such as stratification and flocculation during construction.

[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-solids, low-VOC water-based two-component heavy-duty anti-corrosion primer, characterized in that, It is composed of the following raw materials in parts by weight: 25-45 parts of self-emulsifying waterborne epoxy resin, 25-45 parts of surface-modified pigment and filler system, 3-10 parts of functional additives, 18-35 parts of polyetheramine-amide modified waterborne epoxy curing agent, and 18-35 parts of deionized water.

2. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 1, characterized in that, The self-emulsifying waterborne epoxy resin is an epoxy-amine adduct containing hydroxyl-terminated polyether segments, wherein the epoxy equivalent is 350-550 g / eq, the particle size is 0.05-0.4 μm, and the emulsifier content is ≤2%.

3. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 2, characterized in that, The surface-modified pigment and filler system is composed of the following raw materials in parts by weight: 12-22 parts of zinc phosphate modified with silane coupling agent KH550, 8-15 parts of flaky sericite powder, and 5-10 parts of nano barium sulfate.

4. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 3, characterized in that, The silane coupling agent KH550 modified zinc phosphate has a modifier loading of 1.5%-3% and an oil absorption of ≤35mL / 100g; the flaky sericite powder has an aspect ratio ≥80 and is treated with a titanate coupling agent; the nano barium sulfate has a particle size ≤100nm and its surface is modified with stearic acid.

5. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 4, characterized in that, The functional additive is composed of the following raw materials in parts by weight: 1-3 parts of polycarboxylate dispersant, 0.5-2 parts of organosilicon-polyether block defoamer, 0.5-2 parts of fluorocarbon modified leveling agent, and 2-5 parts of film-forming aid.

6. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 5, characterized in that, The polycarboxylate dispersant has a molecular weight of 5000-10000; the film-forming aid is a compound of propylene glycol phenyl ether and dipropylene glycol methyl ether in a 1:1 ratio.

7. The high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 6, characterized in that, The polyetheramine-amide modified waterborne epoxy curing agent has an amine value of 350-550 mgKOH / g, an active hydrogen equivalent of 120-200 g / mol, and contains polyethylene glycol segments with a molecular weight of 800-1500.

8. A method for preparing a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer as described in any one of claims 1-7, characterized in that, Includes the following steps: 1) Raw material grouping: self-emulsifying waterborne epoxy resin, surface modified pigment and filler system, functional additives and some deionized water are added to group A, and polyetheramine-amide modified waterborne epoxy curing agent and the remaining deionized water are added to group B. 2) Pre-dispersion of Group A: Under stirring at 300-600 r / min, add deionized water, polycarboxylate dispersant, silicone-polyether block defoamer, and fluorocarbon modified leveling agent to the dispersion tank, and stir for 15-25 min until the additives are completely dissolved; 3) Group A resin dispersion: Slowly add self-emulsifying waterborne epoxy resin at a speed of 500-900 r / min, and maintain stirring for 20-30 min to form a stable oil-in-water dispersion system, at which point the particle size distribution D90≤0.6μm; 4) Grinding of pigments and fillers in group A: Increase the rotation speed to 1500-2000 r / min, add silane coupling agent KH550 modified zinc phosphate, flake sericite powder and nano barium sulfate in sequence, disperse at high speed for 30-40 min, then transfer to a sand mill for grinding until the fineness is ≤25μm; 5) Preparation of film-forming aids for component A: Add film-forming aids and stir at a low speed of 200-400 r / min for 10-15 min to obtain the finished product of component A; 6) Dispersion of component B: Mix the polyetheramine-amide-modified waterborne epoxy curing agent with deionized water at 200-500 r / min for 15-20 min until a uniform and transparent solution is formed to obtain the finished product of component B; 7) The finished products of component A and component B are packaged separately to obtain a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer.

9. The method for preparing a high-solids, low-VOC waterborne two-component heavy-duty anti-corrosion primer according to claim 8, characterized in that, In step 4), the diameter of the zirconia beads added to the sand mill is 0.5-1.0 mm, and the grinding pressure is 0.4-0.7 MPa.

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