Coating composition, preparation method therefor and components thereof

Abstract

A coating composition, a preparation method therefor and components thereof. The coating composition comprises a component A and a component B; the components of component A comprise polymeric magnesium aluminum silicate, an amine neutralizer, a defoamer, a dispersant, barium sulfate, zinc phosphate, an epoxy emulsion, a liquid epoxy resin and a thickener; the components of component B comprise a modified amine water-based epoxy curing agent and an anti-flash rust agent.

Description

A coating composition and its preparation method and component

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310718284.7 filed on June 16, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of coating anti-corrosion, and in particular to a coating composition, a preparation method thereof, and applications thereof. Background Art

[0004] Currently, domestic rail transit vehicles are typically coated with water-based epoxy coatings. However, due to the low film thickness of a single coat and the low corrosion resistance of a single coat (typically, a salt spray resistance index of 500 hours at a dry film thickness of 70 μm), multiple coats are required to achieve the required thickness and corrosion resistance, resulting in a complex construction process and a long construction period. Furthermore, if multiple coats are applied before the primer has dried in its first application, residual moisture in the paint film can easily degrade the coating's interlayer adhesion and corrosion resistance.

[0005] Summary of the Invention

[0006] The present disclosure provides a coating composition, a preparation method thereof, and an application thereof to solve the problem of small one-time film thickness of the current coating.

[0007] In a first aspect, the present disclosure provides a coating composition, comprising component A and component B, wherein the components of component A include polymagnesium aluminum silicate, an amine neutralizer, a defoamer, a dispersant, barium sulfate, zinc phosphate, an epoxy emulsion, a liquid epoxy resin, and a thickener; and the components of component B include a modified amine water-based epoxy curing agent and an anti-flash rust agent.

[0008] In a second aspect, the present disclosure provides a method for preparing a coating composition, the method comprising mixing and grinding a first solvent, polymagnesium aluminum silicate, a dispersant, barium sulfate, zinc phosphate, and a portion of a defoaming agent to obtain a primary mixture; mixing the primary mixture, an epoxy emulsion, and a liquid epoxy resin, and then mixing the mixture with a thickener and the remaining defoaming agent to obtain component A; mixing a modified amine water-based epoxy curing agent, a second solvent, and an anti-flash rust agent to obtain component B; and obtaining a coating composition based on components A and B.

[0009] In a third aspect, the present application provides a component comprising a substrate and a coating applied to at least a portion of the surface of the substrate, wherein the coating comprises component A and component B, wherein the components of component A comprise polymagnesium aluminum silicate, an amine neutralizer, a defoaming agent, a dispersant, barium sulfate, zinc phosphate, an epoxy emulsion, a liquid epoxy resin, and a thickener; and the components of component B comprise: a modified amine water-based epoxy curing agent and an anti-flash rust agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0011] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0012] FIG1 shows a flow chart of a method for preparing a coating composition according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0014] Unless otherwise specified, various raw materials, reagents, instruments, and equipment used in the present disclosure can be purchased from the market or prepared by existing methods.

[0015] An embodiment of the present disclosure provides a coating composition, which includes component A and component B, wherein the ingredients of component A include polymagnesium aluminum silicate, an amine neutralizer, a defoamer, a dispersant, barium sulfate, zinc phosphate, an epoxy emulsion, a liquid epoxy resin and a thickener; the ingredients of component B include: a modified amine water-based epoxy curing agent and an anti-flash rust agent.

[0016] In some embodiments, the components of component A include, by weight, 0.1-0.8 parts of magnesium aluminum polysilicate, 0.3-0.8 parts of an amine neutralizer, 0.2-0.5 parts of a defoamer, 0.5-2 parts of a dispersant, 15-30 parts of barium sulfate, 6-12 parts of zinc phosphate, 10-30 parts of an epoxy emulsion, 20-40 parts of a liquid epoxy resin, 0.2-0.5 parts of a thickener, and 6.5-15 parts of a first solvent. The components of component B include, by weight, 75-85 parts of a modified amine waterborne epoxy curing agent, 8-16 parts of a flash rust preventer, and 8-16 parts of a second solvent. The first and second solvents may be selected from deionized water.

[0017] The function of poly magnesium aluminum silicate is to prevent settling and sagging. The mass fraction of poly magnesium aluminum silicate is controlled to be 0.1 to 0.8 parts. The adverse effect of too large a mass fraction is that the coating viscosity is high, which is not conducive to production and construction. The adverse effect of too small a mass fraction is that the coating will sink to the bottom and easily drip during construction.

[0018] The function of the amine neutralizer is to adjust the pH value of the coating and control the mass fraction of the amine neutralizer to 0.3-0.8 parts. Too high or too low pH value of the coating will affect the storage stability, construction performance and anti-flash rust performance of the coating.

[0019] The mass fraction of the defoaming agent is controlled to be 0.2 to 0.5 parts. A too large mass fraction may result in the formation of craters in the coating film, while a too small mass fraction may result in the inability to defoam. In some embodiments, the defoaming agent may be selected from at least one of polydimethylsiloxane and tributyl phosphate.

[0020] The mass fraction of the dispersant is controlled to be 0.5 to 2 parts. A too large mass fraction adversely affects the water resistance and salt spray resistance of the coating, while a too small mass fraction adversely affects the coating's tendency to become rough and sink to the bottom. In some embodiments, the dispersant can be selected from fatty acid polyethylene glycol.

[0021] The role of zinc phosphate is to enhance the anti-corrosion performance of the coating. The mass fraction of zinc phosphate is controlled to be 6 to 12 parts. If the mass fraction is too small, the adverse effect is that the anti-corrosion performance of the coating is weakened and the coating is prone to rust.

[0022] The role of epoxy emulsion is to form a film. The mass fraction of epoxy emulsion is controlled to be 10 to 30 parts. If the mass fraction is too large, the adverse effect is that the coating has high gloss and affects the adhesion between layers. If the mass fraction is too small, the adverse effect is that it affects the adhesion and anti-corrosion performance of the paint film.

[0023] The liquid epoxy resin acts as a film-forming substance. The mass fraction of the liquid epoxy resin is controlled to be between 20 and 40 parts by weight. A higher mass fraction can negatively impact slow film drying, while a lower mass fraction can negatively impact low crosslink density and poor corrosion resistance. In some embodiments, the liquid epoxy resin comprises a liquid bisphenol A epoxy resin. In some embodiments, the liquid bisphenol A epoxy resin comprises at least one of E55, E51, and E44.

[0024] The purpose of controlling the mass fraction of the thickener to 0.2 to 0.5 parts is to adjust the viscosity of the coating and ensure that the viscosity of the coating is within a certain range. In some embodiments, the thickener can be selected from hydrophobic group-modified ethoxylated polyurethane polymers.

[0025] The mass fraction of the modified amine waterborne epoxy curing agent is controlled to be between 75 and 85 parts. A higher mass fraction can negatively impact the corrosion resistance of the paint film, while a lower mass fraction can lead to incomplete reaction between components A and B, affecting the performance of the coating. The modified amine waterborne epoxy curing agent can be selected from CTW-6061B waterborne epoxy curing agent or EH 613w / 80WA waterborne epoxy curing agent.

[0026] The mass fraction of the anti-flash rust agent is controlled to be 8 to 16 parts. If the mass fraction is too large, the storage stability of the coating will be affected. If the mass fraction is too small, the anti-rust performance will not be achieved. The anti-flash rust agent can be selected from SC2190Z or SC2195A.

[0027] In some embodiments, the mass ratio of component A to component B is (7-9): 1. In some embodiments, the mass ratio of component A to component B is 8:1.

[0028] In some embodiments, the epoxy value of the epoxy emulsion is ≤0.25. The reason for controlling the epoxy value of the epoxy emulsion to be ≤0.25 is that the cross-linking density of the paint film can be increased, thereby enhancing the adhesion and anti-corrosion performance of the coating film.

[0029] The coating composition uses epoxy emulsion and liquid epoxy resin to enhance the solid content, crosslinking density, chemical resistance and corrosion resistance of the paint film. When applied as a paint film, the dry film thickness of the paint film can reach more than 150 μm in a single spray application. Under the condition of a dry film thickness of 70 μm, the salt spray resistance performance index can reach 1000 hours, and under the condition of a dry film thickness of 150 μm, the salt spray resistance performance index can reach more than 1600 hours. The interlayer adhesion between the paint film and the oil / water-based acrylic topcoat and the oil / water-based polyurethane topcoat is not less than 5 MPa.

[0030] As shown in FIG1 , based on a general inventive concept, an embodiment of the present disclosure further provides a method for preparing a coating composition, the method comprising steps S1 to S4 .

[0031] In step S1, the first solvent, poly magnesium aluminum silicate, dispersant, barium sulfate, zinc phosphate and part of the defoaming agent are mixed and ground to obtain a primary mixed material;

[0032] In some embodiments, the fineness of the primary mixed material is ≤40 μm. In this embodiment, deionized water, magnesium aluminum polysilicate, a dispersant, a defoaming agent, barium sulfate, and zinc phosphate are added to a dispersion tank in sequence according to metered quantities, the materials are evenly dispersed, and then ground to a fineness of ≤40 μm to obtain the primary mixed material.

[0033] In step S2, the primary mixed material, epoxy emulsion and liquid epoxy resin are mixed, and then mixed with the thickener and the remaining defoamer to obtain component A;

[0034] In some embodiments, the viscosity of Component A is 2-4 Pa·s. In this embodiment, epoxy emulsion is added to a paint mixing tank according to metered quantities, and liquid epoxy resin and the ground primary mixture are added while stirring. A defoamer and a thickener are then added in sequence. The mixture is stirred for 15-30 minutes, and the viscosity of the filtered material is adjusted to 2-4 Pa·s. The mixture is filtered again to remove impurities, and the mixture is discharged to obtain Component A.

[0035] In step S3, the modified amine waterborne epoxy curing agent, the second solvent and the flash rust preventer are mixed to obtain component B;

[0036] In this embodiment, the modified amine water-based epoxy curing agent, deionized water, and anti-flash rust agent are sequentially added into a dispersion tank according to metering, and the materials are evenly dispersed to obtain component B.

[0037] In step S4, a coating composition is obtained based on component A and component B.

[0038] The present disclosure is further described below with reference to the examples. It should be understood that these examples are intended to illustrate the present disclosure only and are not intended to limit the scope of the present disclosure. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If no corresponding national standards are available, the methods were performed in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0039] Example 1

[0040] A coating comprising the following components:

[0041] Example 2

[0042] A coating comprising the following components:

[0043] Example 3

[0044] A coating comprising the following components:

[0045] Example 4

[0046] A coating comprising the following components:

[0047] Example 5

[0048] A coating comprising the following components:

[0049] Comparative Example 1

[0050] A coating comprising the following components:

[0051] Comparative Example 2

[0052] A coating comprising the following components:

[0053] Comparative Example 3

[0054] A coating comprising the following components:

[0055] Comparative Example 4

[0056] A coating comprising the following components:

[0057] The coatings provided in Examples 1 to 5 and Comparative Examples 1 to 4 were tested, and the operation of each test was based on the following standards:

[0058] The experimental results are shown in the following table:

[0059] As can be seen from the above table, when the coating composition provided in the embodiment of the present disclosure is used as a coating layer, the dry film thickness of a single spray application can reach more than 150 μm; under the condition of a dry film thickness of 70 μm, the salt spray resistance performance index can reach 1000 hours, and under the condition of a dry film thickness of 150 μm, the salt spray resistance performance index can reach more than 1600 hours; the interlayer adhesion with oil / water-based acrylic topcoat and oil / water-based polyurethane topcoat is not less than 5 MPa.

[0060] The coating composition provided in the embodiments of the present disclosure enhances the solid content, crosslinking density, chemical resistance and corrosion resistance of the paint film by adding epoxy emulsion and liquid epoxy resin to the components. The dry film thickness of a single spray application can reach more than 150 μm. Under the condition of a dry film thickness of 70 μm, the salt spray resistance performance index can reach 1000 hours, and under the condition of a dry film thickness of 150 μm, the salt spray resistance performance index can reach more than 1600 hours.

[0061] Various embodiments of the present disclosure may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limit to the scope of the present disclosure; therefore, the range description should be considered to have disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In some embodiments, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0062] In the present disclosure, unless otherwise specified, the directional words used, such as "upper" and "lower", refer to the directions of the drawings in the accompanying drawings. In the description of the present disclosure, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In some embodiments, A and B can be singular or plural. In this article, "at least one" refers to one or more, and "plurality" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all mean: a, b, c, a~b (i.e., a and b), a~c, b~c, or a~b~c. In some embodiments, a, b, c can be single or multiple, respectively.

[0063] The foregoing description is intended to illustrate only some specific embodiments of the present disclosure, which will enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not to be limited to the embodiments shown herein, but is to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A coating composition comprising component A and component B, wherein: The components of component A include polysilicate magnesium aluminum, amine neutralizer, defoamer, dispersant, barium sulfate, zinc phosphate, epoxy emulsion, liquid epoxy resin and thickener; the components of component B include modified amine waterborne epoxy curing agent and anti-flash rust agent.

2. The coating composition according to claim 1, wherein The components of component A include, by weight, 0.1 to 0.8 parts of polysilicate magnesium aluminum, 0.3 to 0.8 parts of amine neutralizer, 0.2 to 0.5 parts of defoamer, 0.5 to 2 parts of dispersant, 15 to 30 parts of barium sulfate, 6 to 12 parts of zinc phosphate, 10 to 30 parts of epoxy emulsion, 20 to 40 parts of liquid epoxy resin and 0.2 to 0.5 parts of thickener; and / or The components of the B component include, by weight: 75 to 85 parts of a modified amine waterborne epoxy curing agent and 8 to 16 parts of an anti-flash rust agent.

3. The coating composition according to claim 2, wherein The components of component A also include 6.5 to 15 parts of a first solvent; and / or The components of the B component also include 8 to 16 parts of a second solvent.

4. The coating composition according to claim 3, wherein The mass ratio of the A component to the B component is (7-9):

1.

5. The coating composition according to any one of claims 1 to 4, wherein The epoxy value of the epoxy emulsion is ≤0.

25.

6. The coating composition according to any one of claims 1 to 4, wherein The liquid epoxy resin comprises liquid bisphenol A type epoxy resin; and / or The liquid bisphenol A epoxy resin includes at least one of E55, E51 and E44.

7. The coating composition according to any one of claims 1 to 4, wherein The defoaming agent comprises at least one of polydimethylsiloxane and tributyl phosphate; and / or The dispersant comprises fatty acid polyethylene glycol; and / or The thickener includes a hydrophobe-modified ethoxylated polyurethane polymer.

8. A method for preparing a coating composition, comprising: The first solvent, poly magnesium aluminum silicate, dispersant, barium sulfate, zinc phosphate and part of defoamer are mixed and ground to obtain a primary mixed material; The primary mixed material, epoxy emulsion and liquid epoxy resin are mixed, and then mixed with a thickener and remaining defoamer to obtain component A; Mixing the modified amine waterborne epoxy curing agent, the second solvent and the flash rust preventer to obtain component B; as well as Based on the A component and the B component, a coating composition is obtained.

9. The method for preparing the coating composition according to claim 8, wherein: The fineness of the primary mixed material is ≤40 μm; and / or The viscosity of the component A is 2-4 Pa·s.

10. A component, comprising a substrate and a coating applied to at least a portion of the surface of the substrate, wherein the coating comprises a component A and a component B, wherein: The components of component A include polysilicate magnesium aluminum, amine neutralizer, defoamer, dispersant, barium sulfate, zinc phosphate, epoxy emulsion, liquid epoxy resin and thickener; the components of component B include modified amine waterborne epoxy curing agent and anti-flash rust agent.

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