High temperature resistant epoxy resin coating and preparation method and application thereof

Abstract

The present application relates to the technical field of paint, and discloses a high-temperature-resistant epoxy resin paint, a preparation method and application thereof, the high-temperature-resistant epoxy resin paint comprises 100 parts by weight of epoxy resin, 5-15 parts by weight of organosilicon modified hydroxyl-terminated butadiene styrene rubber, 2-8 parts by weight of polysiloxane, 22-27 parts by weight of curing agent, 0.6-1 part by weight of curing accelerator and the like.The organosilicon modified hydroxyl-terminated butadiene styrene rubber contains an amide bond, is introduced into an epoxy resin molecular chain, has strong interaction with metals such as tinplate, improves the breaking strength and adhesion between the paint film and the metal substrate, the paint film is not prone to peeling and cracking, the salt fog resistance is good, the corrosion resistance is excellent, strong force is formed between the epoxy resin molecular chains, the molecular chain movement is blocked, the deformation and decomposition are not prone to occur at high temperature, the thermal decomposition temperature is higher, and the high-temperature resistance is good.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a high-temperature resistant epoxy resin coating, its preparation method, and its application. Background Technology

[0002] Epoxy resin coatings possess excellent water resistance, electrical insulation, and mechanical strength, and are widely used in chemical pipelines, electronics, vehicles, ships, and building flooring. However, because epoxy resin forms a dense cross-linked network after curing, its flexibility and impact resistance are poor, making it prone to cracking under stress. Furthermore, over long-term use, the adhesion between the paint film and the substrate decreases, leading to peeling and affecting its anti-corrosion and protective properties. To address this, nanoparticles and high-performance rubbers are typically used to toughen and modify epoxy resin coatings.

[0003] Styrene-butadiene rubber (SBR) possesses excellent heat resistance, aging resistance, abrasion resistance, toughness, and elasticity, and is widely used in materials such as epoxy resins, polyurethanes, and phenolic resins to improve their toughness and aging resistance. Chinese patent CN116426172B discloses a corrosion-resistant and acid / alkali-resistant water-based rubber coating and its preparation method. This coating is made by compounding epoxy resin, SBR, modified fillers, and modified silane coupling agents, resulting in a rubber coating with good corrosion resistance. However, this patent does not improve the adhesion between the coating and substrates such as metals. During long-term use, the coating film cracks and peels, affecting its protective performance. Summary of the Invention

[0004] This invention addresses the problem of low high-temperature resistance and toughness in epoxy resin coatings.

[0005] The technical solution of the present invention is: a high-temperature resistant epoxy resin coating, comprising the following raw materials: 100 parts by weight of epoxy resin, 40-54 parts by weight of solvent, 5-15 parts by weight of silicone-modified hydroxyl-terminated styrene-butadiene rubber, 2-8 parts by weight of polysiloxane, 22-27 parts by weight of curing agent, 0.6-1 parts by weight of curing accelerator, 30-44 parts by weight of filler, 0.7-1.2 parts by weight of dispersant, and 0.6-1 parts by weight of defoamer.

[0006] Furthermore, the fillers include fumed silica, mica powder, barium sulfate, and talc powder.

[0007] Furthermore, solvents include acetone, xylene, ethyl acetate, and butyl acetate.

[0008] Furthermore, the curing agent includes phenolic amine.

[0009] Furthermore, the curing accelerator includes DMP-30 2,4,6-tris(dimethylaminomethyl)phenol.

[0010] Furthermore, the preparation method of the high-temperature resistant epoxy resin coating is as follows: (1) In a nitrogen atmosphere, triethylamine, 2-hydroxyacetamide and dimethylchlorosilane were added to tetrahydrofuran, stirred and reacted, filtered and concentrated under reduced pressure, and the crude product was separated by column chromatography to obtain dimethylchloroacetamide siloxane.

[0011] (2) Add hydroxyl-terminated styrene-butadiene rubber to xylene, heat to the reaction temperature in a nitrogen atmosphere, add the catalyst triphenylphosphine rhodium chloride, stir and add dimethylchloroacetamide siloxane to carry out the reaction, cool and add ethanol, filter and wash the precipitate with ethanol, dry to obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0012] (3) Add solvent, epoxy resin, silicone-modified hydroxyl-terminated styrene-butadiene rubber, polysiloxane, filler, dispersant, and defoamer to the shearing machine, shear and disperse, and finally add curing agent and curing accelerator, mix well, and obtain high-temperature resistant epoxy resin coating.

[0013] Furthermore, in (1), the amount of triethylamine is 240-266 parts by weight, 2-hydroxyacetamide is 100 parts by weight, and dimethylchlorosilane is 138-150 parts by weight.

[0014] Furthermore, in (1), the reaction temperature is 15-30℃ and the reaction time is 12-18h.

[0015] Furthermore, (2) the amount of intermediate hydroxyl styrene-butadiene rubber is 100 parts by weight, the amount of triphenylphosphine rhodium chloride is 0.03-0.15 parts by weight, and the amount of dimethyl chloroacetamide siloxane is 8-35 parts by weight.

[0016] Furthermore, in (2), the reaction temperature is 90-100℃ and the reaction time is 8-12h.

[0017] Furthermore, high-temperature resistant epoxy resin coatings are used in the corrosion protection of metal products.

[0018] The beneficial technical effects of this invention are as follows: using triphenylphosphine rhodium chloride as a catalyst, the Si-H bond of dimethylchloroacetamide siloxane is added to the alkenyl group of hydroxyl-terminated styrene-butadiene rubber to obtain organosilicon-modified hydroxyl-terminated styrene-butadiene rubber, which is then compounded with epoxy resin, filler, curing agent, curing accelerator, etc. to obtain a high-temperature resistant epoxy resin coating.

[0019] In the coating curing process, the terminal hydroxyl groups of the silicone-modified hydroxyl-terminated styrene-butadiene rubber react with the epoxy groups of the epoxy resin, thereby grafting the silicone structure and styrene-butadiene rubber molecules into the epoxy resin. This not only toughens the epoxy resin but also improves the compatibility between the epoxy resin and the polysiloxane, giving the polysiloxane a good toughening effect as well, and significantly improving the toughness and impact resistance of the epoxy resin.

[0020] The organosilicon-modified hydroxyl-terminated styrene-butadiene rubber of this invention contains amide bonds, which, when introduced into the epoxy resin molecular chain, can improve the intermolecular forces and enhance cohesion. Furthermore, the amide bonds have a strong interaction with metals such as tinplate, thereby improving the destructive strength and adhesion between the coating film and the metal substrate. The coating film is less prone to peeling and cracking, and its salt spray resistance and corrosion resistance are improved. Simultaneously, the introduction of amide bonds creates strong intermolecular forces between the epoxy resin molecular chains, hindering molecular chain movement and reducing the likelihood of deformation and decomposition at high temperatures. This results in a higher thermal decomposition temperature and improved high-temperature resistance. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Hydroxyl-terminated styrene-butadiene rubber was prepared according to the method described in the journal article "Research on Synthesis of Low Molecular Weight Hydroxyl-Terminated Styrene-Butadiene Rubber by Free Radical Solution Polymerization" (2013, 41(02):27-29). The mass ratio of solvent ethanol, styrene, butadiene, and initiator hydrogen peroxide solution (mass fraction 30%) was 120:80:20:5.

[0023] Example 1: A method for preparing a high-temperature resistant epoxy resin coating: (1) Under a nitrogen atmosphere, 2.66 g of triethylamine, 1 g of 2-hydroxyacetamide, and 1.5 g of dimethylchlorosilane were added to 50 mL of tetrahydrofuran. The mixture was stirred at 20 °C for 12 h. After filtration, the filtrate was concentrated under reduced pressure. The crude product was separated by column chromatography and eluted with petroleum ether-ethyl acetate to obtain dimethylchloroacetamide siloxane. The reaction formula is as follows: .

[0024] (2) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 200mL xylene, heat to 100℃ in a nitrogen atmosphere, add 7mg of triphenylphosphine rhodium chloride catalyst, stir and then add 1.7g of dimethylchloroacetamide siloxane, stir and react for 10h, cool and then add ethanol, filter and wash the precipitate with ethanol, dry to obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0025] (3) Add 200g xylene, 500g epoxy resin E44, 25g organosilicon modified hydroxyl-terminated styrene-butadiene rubber, 10g polysiloxane, 110g fumed silica, 70g talc, 4.4g dispersant (model byk191), and 5g defoamer (model Deqian Defom6500, the same below) to the shearing machine, shear and disperse, and finally add 122g phenolic amine curing agent (model Shenzhen Huiya New Materials HY-H254, the same below) and 4g DMP-30 2,4,6-tris(dimethylaminomethyl)phenol, mix well, and obtain high temperature resistant epoxy resin coating.

[0026] Example 2, a method for preparing a high-temperature resistant epoxy resin coating: (1) In a nitrogen atmosphere, 2.4 g of triethylamine, 1 g of 2-hydroxyacetamide and 1.38 g of dimethylchlorosilane were added to 60 mL of tetrahydrofuran. The mixture was stirred at 25 °C for 18 h. After filtration, the filtrate was concentrated under reduced pressure. The crude product was separated by column chromatography and eluted with petroleum ether-ethyl acetate to obtain dimethylchloroacetamide siloxane.

[0027] (2) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 200mL xylene, heat to 100℃ in a nitrogen atmosphere, add 3mg of triphenylphosphine rhodium chloride catalyst, stir and add 0.8g of dimethylchloroacetamide siloxane, stir and react for 8h, cool and add ethanol, filter and wash the precipitate with ethanol, dry to obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0028] (3) Add 270g acetone, 500g epoxy resin E44, 40g organosilicon modified hydroxyl-terminated styrene-butadiene rubber, 20g polysiloxane, 110g fumed silica, 40g mica powder, 3.5g dispersant, and 4.6g defoamer to the shearing machine, shear and disperse, and finally add 135g phenolic amine curing agent and 4g DMP-30, mix well, and obtain high temperature resistant epoxy resin coating.

[0029] Example 3, a method for preparing a high-temperature resistant epoxy resin coating: (1) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 300mL xylene, heat to 90℃ in a nitrogen atmosphere, add 15mg of triphenylphosphine rhodium chloride catalyst, stir and then add 3.5g of dimethylchloroacetamide siloxane (prepared according to the method of Example 1), stir and react for 12h, cool and then add ethanol, filter and wash the precipitate with ethanol, dry to obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0030] (2) Add 200g xylene, 500g epoxy resin E44, 60g organosilicon modified hydroxyl-terminated styrene-butadiene rubber, 30g polysiloxane, 120g fumed silica, 80g barium sulfate, 6g dispersant, and 4g defoamer to a shearing machine, shear and disperse, and finally add 110g phenolic amine curing agent and 5g DMP-30, mix well, and obtain a high-temperature resistant epoxy resin coating.

[0031] Example 4: A method for preparing a high-temperature resistant epoxy resin coating: (1) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 250mL xylene, heat to 100℃ in a nitrogen atmosphere, add 11mg of triphenylphosphine rhodium chloride catalyst, stir and then add 2.6g of dimethylchloroacetamide siloxane (prepared according to the method of Example 1), stir and react for 10h, cool and then add ethanol, filter and wash the precipitate with ethanol, dry to obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0032] (2) Add 250g butyl acetate, 500g epoxy resin E44, 75g organosilicon modified hydroxyl-terminated styrene-butadiene rubber, 40g polysiloxane, 110g fumed silica, 50g mica powder, 5.2g dispersant and 5g defoamer to a shearing machine, shear and disperse, and finally add 130g phenolic amine curing agent and 4.3g DMP-30, mix well, and obtain high temperature resistant epoxy resin coating.

[0033] Comparative Example 1: A method for preparing an epoxy resin coating: (1) Add 200g xylene, 500g epoxy resin E44, 25g hydroxyl-terminated styrene-butadiene rubber, 10g polysiloxane, 110g fumed silica, 70g talc, 4.4g dispersant, and 5g defoamer to a shearing machine, shear and disperse, and finally add 122g phenolic amine curing agent and 4g DMP-30, mix well, and obtain epoxy resin coating.

[0034] Comparative Example 2: A method for preparing an epoxy resin coating: (1) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 200mL xylene, heat to 100℃ in a nitrogen atmosphere, add 7mg of triphenylphosphine rhodium chloride catalyst, stir, add 1.7g of triethylsilane, stir for 10h, cool, add ethanol, filter, wash the precipitate with ethanol, dry, and obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

[0035] (2) Add 200g xylene, 500g epoxy resin E44, 25g organosilicon modified hydroxyl-terminated styrene-butadiene rubber, 10g polysiloxane, 110g fumed silica, 70g talc, 4.4g dispersant, and 5g defoamer to a shearing machine, shear and disperse, and finally add 122g phenolic amine curing agent and 4g DMP-30, mix well, and obtain epoxy resin coating.

[0036] Comparative Example 3: A method for preparing an epoxy resin coating: (1) Add 10g of hydroxyl-terminated styrene-butadiene rubber to 200mL xylene, heat to 100℃ in a nitrogen atmosphere, add 7mg of triphenylphosphine rhodium chloride catalyst, stir, add 1.7g of 2-hydroxyacetamide, stir for 10h. 2-hydroxyacetamide does not contain SH bonds and cannot react with the alkenyl group of hydroxyl-terminated styrene-butadiene rubber. After cooling, concentrate under reduced pressure to remove xylene, add the product to water, let stand to separate the layers, remove the aqueous phase, dry the oil phase, and the obtained substance is still hydroxyl-terminated styrene-butadiene rubber.

[0037] (2) Add 200g xylene, 500g epoxy resin E44, 25g hydroxyl-terminated styrene-butadiene rubber, 10g polysiloxane, 110g fumed silica, 70g talc, 4.4g dispersant, and 5g defoamer to a shearing machine, shear and disperse, and finally add 122g phenolic amine curing agent and 4g DMP-30, mix well, and obtain epoxy resin coating.

[0038] Apply epoxy resin coating to the tinplate surface, cure at room temperature for 5 days, then cure at 70°C for 1 day, and leave at room temperature for 1 day to form a coating.

[0039] Adhesion tests were conducted according to standard GB / T 5210-2006; the greater the breaking strength, the higher the adhesion. Flexibility was tested according to standard GB / T1732-2020. The coating's resistance to neutral salt spray was tested according to standard GB / T 10125-2021, and the time it took for the coating to crack was recorded.

[0040] The thermal properties of the coating were tested using a thermogravimetric analyzer in a nitrogen atmosphere at a heating rate of 10℃ / min and a temperature range of 20-700℃.

[0041] Table 1 Performance of Coatings Compared to Comparative Example 1, the organosilicon-modified hydroxyl-terminated styrene-butadiene rubber in Example 1 reacts with the epoxy groups of the epoxy resin, grafting the organosilicon structure and styrene-butadiene rubber molecules into the epoxy resin. This not only toughens the epoxy resin but also improves the compatibility between the epoxy resin and the polysiloxane, giving the polysiloxane a good toughening effect as well. This significantly improves the toughness and impact resistance of the epoxy resin. Furthermore, the organosilicon-modified hydroxyl-terminated styrene-butadiene rubber contains amide bonds, which can enhance the intermolecular forces of the epoxy resin molecules, strengthen the cohesive force, and have a strong interaction with metals such as tinplate. This improves the adhesion between the coating film and the metal substrate, resulting in a higher breaking strength than Comparative Example 1. The coating film is less prone to peeling and cracking, and the salt spray resistance and corrosion resistance are improved. Simultaneously, the strong intermolecular forces between the epoxy resin molecules hinder molecular chain movement, making it less prone to deformation and decomposition at high temperatures, resulting in a higher thermal decomposition temperature and better high-temperature resistance.

[0042] Comparative Example 2 utilizes the Si-H bond of triethylsilane to react with the alkenyl group of hydroxyl-terminated styrene-butadiene rubber. The resulting organically modified hydroxyl-terminated styrene-butadiene rubber does not contain amide bonds. The adhesion and destructive strength between the coating film and the metal substrate are lower than those of Example 1. Furthermore, its resistance to neutral salt spray and corrosion is poor. At the same time, its initial thermal decomposition temperature is also lower than that of Example 1, indicating poor high-temperature resistance.

[0043] The 2-hydroxyacetamide in Comparative Example 3 does not contain SH bonds and cannot react with the alkenyl group of hydroxyl-terminated styrene-butadiene rubber. The resulting substance is still hydroxyl-terminated styrene-butadiene rubber. The adhesion and destructive strength between the coating film and the metal substrate are lower than those in Example 1. Furthermore, its resistance to neutral salt spray and corrosion protection are poor, and its initial thermal decomposition temperature is also lower.

Claims

1. A high-temperature resistant epoxy resin coating, characterized in that, The high-temperature resistant epoxy resin coating comprises the following raw materials: 100 parts by weight of epoxy resin, 40-54 parts by weight of solvent, 5-15 parts by weight of silicone-modified hydroxyl-terminated styrene-butadiene rubber, 2-8 parts by weight of polysiloxane, 22-27 parts by weight of curing agent, 0.6-1 parts by weight of curing accelerator, 30-44 parts by weight of filler, 0.7-1.2 parts by weight of dispersant, and 0.6-1 parts by weight of defoamer.

2. The high-temperature resistant epoxy resin coating according to claim 1, characterized in that, The filler is any one or more of fumed silica, mica powder, barium sulfate, and talc.

3. The high-temperature resistant epoxy resin coating according to claim 1, characterized in that, The solvent is acetone, xylene, ethyl acetate or butyl acetate.

4. The high-temperature resistant epoxy resin coating according to claim 1, characterized in that, The curing agent is phenolic amine, and the curing accelerator is DMP-30.

5. A method for preparing a high-temperature resistant epoxy resin coating as described in any one of claims 1-4, characterized in that, The preparation method is as follows: add solvent, epoxy resin, silicone-modified hydroxyl-terminated styrene-butadiene rubber, polysiloxane, filler, dispersant, and defoamer to a shearing machine, shear and disperse, and finally add curing agent and curing accelerator, mix well, and obtain high-temperature resistant epoxy resin coating.

6. The method for preparing the high-temperature resistant epoxy resin coating according to claim 5, characterized in that, The preparation method of the organosilicon-modified hydroxyl-terminated styrene-butadiene rubber is as follows: (1) In a nitrogen atmosphere, add 240-266 parts by weight of triethylamine, 100 parts by weight of 2-hydroxyacetamide and 138-150 parts by weight of dimethylchlorosilane to tetrahydrofuran, stir and react, filter and concentrate the filtrate under reduced pressure, and separate the crude product by column chromatography to obtain dimethylchloroacetamide siloxane. (2) Add 100 parts by weight of hydroxyl-terminated styrene-butadiene rubber to xylene, heat to the reaction temperature in a nitrogen atmosphere, add 0.03-0.15 parts by weight of triphenylphosphine rhodium chloride catalyst, stir, add 8-35 parts by weight of dimethylchloroacetamide siloxane, react, cool, add ethanol, filter, wash the precipitate, dry, and obtain organosilicon modified hydroxyl-terminated styrene-butadiene rubber.

7. The method for preparing the high-temperature resistant epoxy resin coating according to claim 6, characterized in that, The reaction temperature in (1) is 15-30℃ and the reaction time is 12-18h.

8. The method for preparing the high-temperature resistant epoxy resin coating according to claim 6, characterized in that, The reaction temperature in (2) is 90-100℃ and the reaction time is 8-12h.

9. The application of a high-temperature resistant epoxy resin coating obtained by the preparation method according to any one of claims 1-8 in the corrosion protection of metal products.

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