An oil-based epoxy thick film primer and its preparation method

Abstract

This invention discloses an oil-based epoxy thick film primer and its preparation method, belonging to the technical field of epoxy resin-based coating preparation. The oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component includes the following components: 20-40 parts epoxy resin, 2-7 parts component A, 6-12 parts diluent, 1-10 parts filler, and 0-6 parts additives. The second component includes the following components: 30-60 parts curing agent, 3-6 parts component B, and 5-11 parts accelerator. This invention improves the flexibility of the thick film primer and reduces stress caused by the curing rate through component modification.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin-based coating preparation technology, and particularly to an oil-based epoxy thick film primer and its preparation method. Background Technology

[0002] Epoxy resin refers to organic polymers containing two or more epoxy groups in their molecules, or polymers that undergo cross-linking reactions with various types of curing agents to form insoluble and infusible polymers with a three-dimensional network structure. Epoxy resins possess excellent physical, mechanical, and electrical insulation properties, adhesion to various materials, and flexibility in their application processes, qualities unmatched by other thermosetting plastics. Therefore, they can be used to make coatings, composite materials, casting materials, adhesives, molding materials, and injection molding materials, finding wide application in various sectors of the national economy.

[0003] Common properties of epoxy resins include excellent chemical resistance, especially alkali resistance; strong film adhesion, particularly to metals; and good heat resistance, electrical insulation, and color retention. Therefore, epoxy resins account for a large proportion of coating applications. Due to their high solids content, they can be used as thick-film coatings, especially as anti-corrosion paints, metal primers, and insulating paints to protect the substrate from damage. However, after curing, epoxy resins form a three-dimensional network structure with high crosslinking density, making them brittle and with poor impact resistance. The curing process of epoxy primers is gradual from the inside out. If the coating thickness is too large, incomplete internal curing can create tension, increasing the internal tension of the coating and easily leading to problems such as cracking, peeling, and blistering. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an oil-based epoxy thick film primer that can reduce the curing internal stress of epoxy thick film primer to ensure the integrity of the coating and its preparation method.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises 20-40 parts epoxy resin, 2-7 parts component A, 6-12 parts diluent, 1-10 parts filler, and 0-6 parts additives; the second component comprises 30-60 parts curing agent, 3-6 parts component B, and 5-11 parts accelerator.

[0007] The preparation method of component A includes the following steps:

[0008] Weigh out cage-type γ-glycidyl etheroxypropyl silsesquioxane and dissolve it in xylene solvent. Add amino polydimethylsiloxane, stir and mix thoroughly, then heat to 110-120℃ and keep warm while stirring for 1-3 hours. After the reaction is complete, cool to room temperature, add an equal volume of acetonitrile solvent to dilute the reaction system, take the supernatant, evaporate the solvent and obtain component A.

[0009] The preparation method of component B includes the following steps:

[0010] Weigh 2,6-pyridinedicarboxyl chloride and dissolve it in dichloromethane solvent to obtain solution A; weigh diamine and dissolve it in dichloromethane solvent, add triethylamine as an acid-binding agent to obtain solution B; add solution B dropwise to solution A; after the addition is complete, stir the reaction at room temperature for 6-12 hours; after the reaction is complete, wash with deionized water and saturated sodium chloride solution in sequence; after the organic phase is dried, evaporate the solvent to obtain component B.

[0011] Preferably, the mass ratio of the first component to the second component is 4:(1-2).

[0012] Preferably, the epoxy resin is a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin, for example, E20, E44, E51.

[0013] Preferably, the diluent is one or more of the following: polypropylene glycol diglycidyl ether, o-tolyl glycidyl ether, trimethylolpropane triglycidyl ether, benzyl glycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and epoxidized soybean oil.

[0014] Preferably, the filler is one or more of nano-silica, titanium dioxide, aluminum oxide, magnesium hydroxide, zirconium oxide, calcium carbonate, calcium silicate, and talc.

[0015] Preferably, the additive is one or more of coupling agents, dispersants, defoamers, leveling agents, colorants, and flame retardants; for example, the coupling agent is a silane coupling agent, such as KH560; the dispersant is a surfactant, such as BYK220S type organosilicon dispersant; the defoamer is a polyether organosilicon SXP-107; the leveling agent is BYK-346 or BYK-333; the colorant is a pigment, such as carbon black; and the flame retardant is magnesium hydroxide / aluminum or hexaphenoxycyclophosphamide.

[0016] Preferably, the curing agent is an aliphatic polyamine curing agent, a phenolic amine curing agent, a modified polyether amine curing agent, or a modified amide amine curing agent, such as ZY-1078, EC301, T31, H113, or D0115.

[0017] Preferably, the accelerator is an imidazole accelerator, an organophosphorus accelerator, or a diazacyclic olefin accelerator, such as triphenylphosphine, 2-methylimidazole, 1,5-diazabicyclo[4.3.0]non-5-ene, or DMP30.

[0018] Preferably, the mass ratio of the cage-like γ-glycidoxypropylsilsesquioxane to the aminopolydimethylsiloxane is 1:(6-8).

[0019] Preferably, the diamine is p-phenylenediamine, 4,4-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4-aminophenyl 4-aminobenzoate, or 4,4'-bis(3-aminophenoxy)diphenyl sulfone; the mass ratio of 2,6-pyridinedicarboxyl chloride to the diamine and the triethylamine is 1:(2-4):(1.4-1.8).

[0020] The present invention also provides a method for preparing the oil-based epoxy thick film primer, the steps of which are to weigh each component raw material according to the ratio and mix them to obtain a first component and a second component, and then stir and mix the first component and the second component according to the ratio to obtain the primer.

[0021] This invention uses cage-like γ-glycidyl etheroxypropyl silsesquioxane as a raw material. Through the ring-opening reactive grafting of polydimethylsiloxane onto epoxy groups by amine groups, the cage-like silsesquioxane is introduced into epoxy resin thick-film coatings via copolymerization or non-copolymerization. Based on the ether and methylene groups in its structure, its relatively small steric hindrance endows it with strong spatial mobility, while also increasing the distance between the epoxy curing crosslinking polymer chains, improving the flexibility of the coating film, and reducing stress caused by the curing rate. The polydimethylsiloxane improves the dispersibility of silsesquioxane in the coating and also imparts good waterproof and self-cleaning properties to the coating. Furthermore, this invention prepares a modified polyamine with pyridine dicarboxamide groups through the substitution reaction of acyl chloride and amine groups. This modified polyamine is used as an epoxy curing agent to introduce easily hydrogen-bonded elastic structural units into the curing system, further improving the flexibility of the coating film. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Example 1

[0023] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises the following components: 34 parts epoxy resin E51, 5 parts component A, 8 parts 1,4-butanediol diglycidyl ether, 2 parts nano-silica filler, and 0.1 parts KH560; the second component comprises the following components: 56 parts modified polyether amine curing agent ZY-1078 (Klamar), 5 parts component B, and 6.8 parts 2-methylimidazole.

[0024] The preparation method of component A includes the following steps:

[0025] Weigh out cage-type γ-glycidoxypropylsilsesquioxane and dissolve it in xylene solvent. Add aminopolydimethylsiloxane (weight average molecular weight 2000), stir and mix thoroughly, then heat to 110℃ and keep at this temperature for 2 hours. After the reaction is complete, cool to room temperature, add an equal volume of acetonitrile solvent to dilute the reaction system, take the supernatant, and evaporate the solvent to obtain component A. The mass ratio of cage-type γ-glycidoxypropylsilsesquioxane to aminopolydimethylsiloxane is 1:6.9.

[0026] The preparation method of component B includes the following steps:

[0027] 2,6-pyridinedicarboxylic acid chloride was weighed and dissolved in dichloromethane solvent to obtain solution A; 4,4-diaminodiphenyl ether was weighed and dissolved in dichloromethane solvent, and triethylamine was added as an acid-binding agent to obtain solution B. Solution B was added dropwise to solution A. After the addition was complete, the mixture was stirred at room temperature for 8 hours. After the reaction was completed, the mixture was washed successively with deionized water and saturated sodium chloride solution. The organic phase was dried and the solvent was evaporated to obtain component B; wherein, the mass ratio of 2,6-pyridinedicarboxylic acid chloride to 4,4-diaminodiphenyl ether and triethylamine was 1:3.2:1.6.

[0028] The mass ratio of the first component to the second component is 4:1.2;

[0029] The preparation method of the oil-based epoxy thick film primer is as follows: first, weigh each component raw material according to the ratio and mix them to obtain the first component and the second component respectively; then, stir and mix the first component and the second component according to the ratio to obtain the final product. Example 2

[0030] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises the following components: 34 parts epoxy resin E51, 8 parts 1,4-butanediol diglycidyl ether, 2 parts nano-silica filler, and 0.1 parts KH560; the second component comprises the following components: 56 parts modified polyetheramine curing agent ZY-1078 (Klamar), 5 parts component B, and 6.8 parts 2-methylimidazole.

[0031] The preparation method of component B includes the following steps:

[0032] 2,6-pyridinedicarboxylic acid chloride was weighed and dissolved in dichloromethane solvent to obtain solution A; 4,4-diaminodiphenyl ether was weighed and dissolved in dichloromethane solvent, and triethylamine was added as an acid-binding agent to obtain solution B. Solution B was added dropwise to solution A. After the addition was complete, the mixture was stirred at room temperature for 8 hours. After the reaction was completed, the mixture was washed successively with deionized water and saturated sodium chloride solution. The organic phase was dried and the solvent was evaporated to obtain component B; wherein, the mass ratio of 2,6-pyridinedicarboxylic acid chloride to 4,4-diaminodiphenyl ether and triethylamine was 1:3.2:1.6.

[0033] The mass ratio of the first component to the second component is 4:1.2;

[0034] The preparation method of the oil-based epoxy thick film primer is as follows: first, weigh each component raw material according to the ratio and mix them to obtain the first component and the second component respectively; then, stir and mix the first component and the second component according to the ratio to obtain the final product. Example 3

[0035] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises the following components: 34 parts epoxy resin E51, 5 parts component A, 8 parts 1,4-butanediol diglycidyl ether, 2 parts nano-silica filler, and 0.1 parts KH560; the second component comprises the following components: 56 parts modified polyether amine curing agent ZY-1078 (Klamar), and 6.8 parts 2-methylimidazole.

[0036] The preparation method of component A includes the following steps:

[0037] Weigh out cage-type γ-glycidoxypropylsilsesquioxane and dissolve it in xylene solvent. Add aminopolydimethylsiloxane (weight average molecular weight 2000), stir and mix thoroughly, then heat to 110℃ and keep at this temperature for 2 hours. After the reaction is complete, cool to room temperature, add an equal volume of acetonitrile solvent to dilute the reaction system, take the supernatant, and evaporate the solvent to obtain component A. The mass ratio of cage-type γ-glycidoxypropylsilsesquioxane to aminopolydimethylsiloxane is 1:6.9.

[0038] The mass ratio of the first component to the second component is 4:1.2;

[0039] The preparation method of the oil-based epoxy thick film primer is as follows: first, weigh each component raw material according to the ratio and mix them to obtain the first component and the second component respectively; then, stir and mix the first component and the second component according to the ratio to obtain the final product. Example 4

[0040] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises the following components: 34 parts epoxy resin E51, 5 parts component A, 8 parts 1,4-butanediol diglycidyl ether, 2 parts nano-silica filler, and 0.1 parts KH560; the second component comprises the following components: 56 parts modified polyether amine curing agent ZY-1078 (Klamar), 5 parts component B, and 6.8 parts 2-methylimidazole.

[0041] Component A is an amino-polydimethylsiloxane with a weight-average molecular weight of 2000.

[0042] The preparation method of component B includes the following steps:

[0043] 2,6-pyridinedicarboxylic acid chloride was weighed and dissolved in dichloromethane solvent to obtain solution A; 4,4-diaminodiphenyl ether was weighed and dissolved in dichloromethane solvent, and triethylamine was added as an acid-binding agent to obtain solution B. Solution B was added dropwise to solution A. After the addition was complete, the mixture was stirred at room temperature for 8 hours. After the reaction was completed, the mixture was washed successively with deionized water and saturated sodium chloride solution. The organic phase was dried and the solvent was evaporated to obtain component B; wherein, the mass ratio of 2,6-pyridinedicarboxylic acid chloride to 4,4-diaminodiphenyl ether and triethylamine was 1:3.2:1.6.

[0044] The mass ratio of the first component to the second component is 4:1.2;

[0045] The preparation method of the oil-based epoxy thick film primer is as follows: first, weigh each component raw material according to the ratio and mix them to obtain the first component and the second component respectively; then, stir and mix the first component and the second component according to the ratio to obtain the final product. Example 5

[0046] An oil-based epoxy thick film primer is composed of a first component and a second component. By weight, the first component comprises 34 parts of epoxy resin E51, 8 parts of 1,4-butanediol diglycidyl ether, 2 parts of nano-silica filler, and 0.1 parts of KH560; the second component comprises 56 parts of modified polyetheramine curing agent ZY-1078 (Klamar) and 6.8 parts of 2-methylimidazole.

[0047] The mass ratio of the first component to the second component is 4:1.2;

[0048] The preparation method of the oil-based epoxy thick film primer is as follows: first, weigh each component raw material according to the ratio and mix them to obtain the first component and the second component respectively; then, stir and mix the first component and the second component according to the ratio to obtain the final product.

[0049] The adhesion and elasticity of the oil-based epoxy thick film primers described in Examples 1-5 were measured. The film thickness was 1000 μm. Adhesion was measured according to GB / T5210, and drying time and impact resistance were measured according to chemical standard HG / T 4566-2013. The test results are shown in the table below:

[0050]

[0051] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. An oil-based epoxy thick-film primer, characterized in that, Composed of a first component and a second component, the first component comprises the following components by weight: 20-40 parts epoxy resin, 2-7 parts component A, 6-12 parts diluent, 1-10 parts filler, and 0-6 parts additives. The second component comprises the following components: 30-60 parts of curing agent, 3-6 parts of component B, and 5-11 parts of accelerator; The preparation method of component A includes the following steps: Weigh out cage-type γ-glycidyl etheroxypropyl silsesquioxane and dissolve it in xylene solvent. Add amino polydimethylsiloxane, stir and mix thoroughly, then heat to 110-120℃ and keep warm while stirring for 1-3 hours. After the reaction is complete, cool to room temperature, add an equal volume of acetonitrile solvent to dilute the reaction system, take the supernatant, evaporate the solvent and obtain component A. The preparation method of component B includes the following steps: Weigh 2,6-pyridinedicarboxyl chloride and dissolve it in dichloromethane solvent to obtain solution A; weigh diamine and dissolve it in dichloromethane solvent, add triethylamine as an acid-binding agent to obtain solution B; add solution B dropwise to solution A; after the addition is complete, stir the reaction at room temperature for 6-12 hours; after the reaction is complete, wash with deionized water and saturated sodium chloride solution in sequence; dry the organic phase and evaporate the solvent to obtain component B, wherein the diamine is 4,4-diaminodiphenyl ether.

2. The oil-based epoxy thick film primer according to claim 1, characterized in that, The mass ratio of the first component to the second component is 4:(1-2).

3. The oil-based epoxy thick film primer according to claim 1, characterized in that, The epoxy resin is bisphenol A type epoxy resin and / or bisphenol F type epoxy resin.

4. The oil-based epoxy thick film primer according to claim 1, characterized in that, The diluent is one or more of the following: polypropylene glycol diglycidyl ether, o-tolyl glycidyl ether, trimethylolpropane triglycidyl ether, benzyl glycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and epoxidized soybean oil.

5. The oil-based epoxy thick film primer according to claim 1, characterized in that, The additive is one or more of the following: coupling agent, dispersant, defoamer, leveling agent, colorant, and flame retardant.

6. The oil-based epoxy thick film primer according to claim 1, characterized in that, The curing agent is an aliphatic polyamine curing agent, a phenolic amine curing agent, a modified polyether amine curing agent, or a modified amide amine curing agent.

7. The oil-based epoxy thick-film primer according to claim 1, characterized in that, The accelerator is an imidazole accelerator, an organophosphorus accelerator, or a diazacyclic olefin accelerator.

8. The oil-based epoxy thick film primer according to claim 1, characterized in that, The mass ratio of the cage-type γ-glycidyl etheroxypropyl silsesquioxane to the amino polydimethylsiloxane is 1:(6-8).

9. The oil-based epoxy thick-film primer according to claim 1, characterized in that, The mass ratio of the 2,6-pyridinedicarboxyl chloride to the diamine and the triethylamine is 1:(2-4):(1.4-1.8).

10. A method for preparing an oil-based epoxy thick film primer according to any one of claims 1-9, characterized in that, Each component raw material is weighed and mixed according to the ratio to obtain the first component and the second component. The first component and the second component are then stirred and mixed according to the ratio to obtain the final product.

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