An epoxy polyolefin thermosetting coating material, its preparation method and application

Abstract

The application belongs to the technical field of paint, and particularly relates to an epoxy polyolefin thermosetting paint, a preparation method and application thereof. The epoxy polyolefin thermosetting paint comprises component A and component B. Raw materials of the component A comprise, in weight percentage, 50-70 parts of epoxy resin, 20-30 parts of polyolefin resin, 10-15 parts of auxiliary additive and 20-50 parts of mica powder. Raw materials of the component B comprise, in weight percentage, 70-80 parts of polyamide resin and 2-10 parts of a catalyst. The paint has excellent physical properties, hot water resistance, processing adaptability and wide applicability. The epoxy-polyolefin crosslinking forms a high-toughness and impact-resistant structure, is hydrophobic, resistant to high-temperature and high-pressure corrosion, easy to spray due to low viscosity, and suitable for multiple scenes in harsh environments.

Description

Technical Field

[0001] This invention relates to an epoxy polyolefin thermosetting coating, its preparation method and application, belonging to the field of coating technology. Background Technology

[0002] In the petrochemical and fine chemical industries, chemical reactors, high-temperature pipelines, storage tanks, and steel structures in acid and alkali workshops face multiple harsh conditions, including long-term exposure to medium and high temperatures, strong acid and alkali corrosion, organic solvents, and chemical waste. Coatings must withstand continuous use at temperatures above 120°C for extended periods, possess excellent resistance to strong acids, strong alkalis, and organic solvent penetration, and exhibit good thermal cycling stability, remaining undamaged and free from cracking or peeling after over a hundred cycles of hot and cold temperatures. They must also resist long-term penetration and corrosion by chemical media, eliminating the risk of equipment corrosion and leakage due to coating damage.

[0003] In the power energy sector, equipment such as thermal power boilers, high-temperature flues, substation structures, outdoor power steel structures, and photovoltaic supporting facilities are exposed to high-temperature baking, strong outdoor ultraviolet aging, industrial dust, and acid rain corrosion for extended periods. On the one hand, coatings are required to possess excellent high-temperature resistance and thermal insulation properties to withstand continuous scouring by high-temperature flue gas; on the other hand, they must meet long-term weather resistance standards, with salt spray resistance lasting 2000–3000 hours.

[0004] In the metallurgical and high-temperature industrial sectors, facilities such as blast furnaces, heat treatment equipment, industrial kilns, and high-temperature exhaust pipes operate under continuous high-temperature conditions exceeding 100°C for extended periods, with localized instantaneous high-temperature shocks. This field demands extremely high heat resistance from coatings, requiring overcoming the drawbacks of traditional epoxy coatings that are prone to softening and degradation at high temperatures, and ensuring the integrity of the paint film structure under high-temperature environments.

[0005] With the rapid development of industry, the performance requirements for coatings in these fields are increasingly stringent. However, traditional epoxy coatings have certain limitations in terms of heat resistance, corrosion resistance, and chemical resistance. The typical temperature range for epoxy coatings to withstand heat media is 60-100℃; exceeding this temperature will damage the coating film, causing it to lose its anti-corrosion properties and deteriorate in performance. Furthermore, the corrosion resistance and chemical resistance of epoxy coatings need improvement in special environments such as high humidity and high pH values.

[0006] To address these issues, researchers have been exploring new coating materials and technologies. Among them, polyolefin resins have become an ideal modification material due to their excellent heat resistance, chemical resistance, and mechanical properties. However, polyolefin resins have poor compatibility with epoxy resins and are prone to sagging at room temperature, affecting the quality and performance of the coating.

[0007] Therefore, developing a novel coating that can combine epoxy resin and polyolefin resin, overcoming the limitations of traditional epoxy coatings and solving the incompatibility problem between polyolefin resin and epoxy resin, has become an important direction in current coating research. This new coating not only needs to possess excellent heat resistance and corrosion resistance, but also good processability and applicability to meet the stringent requirements of different fields.

[0008] Several invention patents have been granted to address the issues of coating toughness, impact resistance, corrosion resistance, and chemical resistance. For example: Chinese Patent Publication No. CN106554705A discloses a solvent-free epoxy coating and its preparation method. The coating comprises a first component and a second component. The first component includes bisphenol F resin, bisphenol A epoxy resin E51, liquid petroleum resin, and glycidyl isomeric monocarboxylic acid esters, etc. The second component includes phenolic-modified aliphatic amines and allylphenol-modified alicyclic amines, etc. This coating exhibits excellent thin-film properties, enabling the achievement of thin coating thicknesses, effectively reducing coating costs and improving construction efficiency. However, this coating still has shortcomings in heat resistance and cannot meet the anti-corrosion requirements under high-temperature environments.

[0009] Chinese patent CN111334166A discloses a high-temperature, high-pressure, solvent-free, heavy-duty anti-corrosion coating composition. This coating comprises component A and component B. Component A consists of phenolic epoxy resin, bisphenol F resin, and a reactive toughening agent, while component B is a mixture of modified aliphatic amines and modified phenolic amines. The coating itself is a solvent-free system, can be applied normally between 0-40℃, and cures at room temperature. However, its high-temperature resistance still needs improvement, as it is difficult to maintain good anti-corrosion performance under high-temperature environments.

[0010] Chinese Patent Publication No. CN118126625A discloses a hard-film polysiloxane coating, its preparation method, and its application. This coating is obtained by reacting epoxy resin and / or modified epoxy resin with a silane coupling agent to form a silane coupling agent-modified epoxy resin, which is then mixed with a polysiloxane containing active end groups, followed by a series of reaction steps. In this coating, the epoxy resin and polysiloxane are coupled together by the coupling agent to form a multi-layered cross-linked network structure, within which functional fillers are filled. However, the ratio of epoxy resin to modified epoxy resin still needs optimization to obtain better toughness, adhesion, and abrasion resistance.

[0011] In the aforementioned applications, the high-temperature resistance of existing coatings still needs improvement, as they struggle to maintain good anti-corrosion performance under high-temperature environments and cannot meet stringent anti-corrosion requirements. Existing coating formulations and properties need further optimization to enhance toughness, impact resistance, corrosion resistance, chemical resistance, and high-temperature resistance, thereby meeting the stringent requirements of different fields. Summary of the Invention

[0012] To address the above-mentioned problems, this invention provides an epoxy polyolefin thermosetting coating, its preparation method, and its application.

[0013] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides an epoxy polyolefin thermosetting coating, the epoxy polyolefin thermosetting coating comprising component A and component B; The raw materials of component A, by weight, include: 50-70 parts epoxy resin, 20-30 parts polyolefin resin, 10-15 parts auxiliary additives, and 20-50 parts mica powder. The raw materials of component B, by weight, include: 70-80 parts of polyamide resin and 2-10 parts of catalyst.

[0014] This invention solves the problems of heat resistance, corrosion resistance, and compatibility of traditional coatings. Specifically, the design of components A and B allows for mixing during application, avoiding pre-reaction issues during storage and ensuring controllable reaction. The epoxy resin in component A serves as the base resin, providing thermosetting and adhesive properties and forming the core of the cross-linked network. The polyolefin resin in component A undergoes specific modification to enhance heat and chemical resistance, resolving compatibility issues with epoxy resin and preventing sagging. Auxiliary additives in component A optimize processing performance, such as improving leveling and reducing defects. Mica powder in component A acts as a filler, enhancing heat resistance and mechanical strength and reducing deformation at high temperatures. The polyamide resin in component B acts as a curing agent, reacting with the epoxy resin in component A to form a cross-linked structure, enhancing corrosion resistance. The catalyst in component B accelerates the curing process, and the polyolefin resin participates in the cross-linking reaction through ring-opening, improving the coating's chemical resistance and heat resistance.

[0015] Preferably, the polyolefin resin is prepared by reacting maleic anhydride-modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane-modified polybutadiene, and butyl acrylate.

[0016] The mass ratio of the maleic anhydride-modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane-modified polybutadiene, and butyl acrylate is (30-45):(5-10):(5-10):(1-5):(5-10); the auxiliary additives are selected from inorganic pigments and fillers. The inorganic pigments and fillers include activated calcium carbonate and / or feldspar powder.

[0017] Preferably, the catalyst in component B is a transition metal catalyst; the transition metal catalyst includes ruthenium catalyst, platinum catalyst and cobalt catalyst, and the mass ratio of the three is (20-35):(20-40):(35-45).

[0018] In a second aspect, the present invention provides a method for preparing the epoxy polyolefin thermosetting coating described in the first aspect, comprising the following steps: (1) Preparation of component A: Mix epoxy resin, polyolefin resin and auxiliary additives evenly, grind them, and then add mica powder and mix evenly. (2) Preparation of component B: Mix the polyamide resin and catalyst and stir evenly.

[0019] This invention involves uniformly mixing epoxy resin, polyolefin resin, and auxiliary additives, which promotes initial compatibility between different resins and avoids interfacial separation caused by incompatibility between polyolefin resin and epoxy resin. Next, sand milling is performed, which refines the particles in the mixture, improves dispersion uniformity, prevents agglomeration, and lays the foundation for the subsequent addition of additives. Then, mica powder is added and stirred evenly. The mica powder, added after sand milling, avoids structural damage during grinding, ensures uniform distribution in the coating, and enhances the heat resistance and mechanical strength of the coating. In the step of preparing component B, polyamide resin and catalyst are mixed and stirred evenly, which achieves uniform dispersion of the curing agent component, facilitating rapid and sufficient catalyst initiation of the reaction when mixed with component A, avoiding incomplete curing or performance defects. Overall, this method, through step-by-step optimization of component processing, solves the problems of uniformity, stability, and reaction sufficiency in coating preparation in the prior art, providing a guarantee for the consistency of coating performance.

[0020] Preferably, the preparation process of the polyolefin resin in step (1) is as follows: maleic anhydride modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane modified polybutadiene and butyl acrylate are mixed, and the mixture is heated to 130℃-160℃ under catalytic conditions and reacted for 3-5 hours.

[0021] Preferably, in step (1), the grinding time is 30-40 minutes.

[0022] Preferably, in step (1), the mica powder is added after the epoxy resin, polyolefin resin and auxiliary additives are mixed and milled.

[0023] Thirdly, the present invention provides an application of the epoxy polyolefin thermosetting coating described in the first aspect, wherein the coating is applied by mixing component A and component B and spraying them onto the surface of a substrate; specifically, the coating is applied by an airless spraying process.

[0024] Preferably, the steel surface is sandblasted according to the SSPC SP10 standard before spraying.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This coating has a special structure formed by the cross-linking reaction of epoxy and polyolefin resins, which has excellent toughness and impact resistance and can withstand large external impacts without cracking or damage. At the same time, it has a good balance of stiffness and toughness, which can provide a certain degree of flexibility while ensuring the strength of the material.

[0026] (2) The coating prepared by the present invention is hydrophobic and can still maintain excellent adhesion and performance in hot water at high temperature, and still has high anti-corrosion performance in high temperature and high pressure water.

[0027] (3) The coating prepared by this invention has ultra-low viscosity, enabling rapid processing. A single spray coating thickness of up to 1 mm can be achieved without sagging. The curing time is adjustable, and the spraying temperature range is wide, allowing it to adapt to different construction environments and process requirements. It can be applied to harsh corrosive environments such as oil pipelines, municipal heating, and factory corrosion protection. Detailed Implementation

[0028] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0029] The specific sources of raw materials in the following preparation examples, embodiments, and comparative examples are as follows: Epoxy resin: Bisphenol A type epoxy resin of model SM618 from Sanmu Company was selected, with an epoxy equivalent of 190g / eq.

[0030] Polyamide resin: The polyamide curing agent BS890 from Baisheng Company was selected, with an amine value of 271 mgKOH / g.

[0031] Catalyst mixture: Ruthenium catalyst is Kaida Chemical JWH-98, platinum catalyst is Elyst Pt500550, and cobalt catalyst is Borchers Deca 421 aqua.

[0032] Auxiliary additives: composed of dispersant, defoamer, and leveling agent, in a weight ratio of (0.3-0.8):(0.2-0.5):(0.1-0.3), based on a total of 100 parts of epoxy resin and polyolefin resin. Optionally, the dispersant is BYK-161, and the defoamer is BYK-066.

[0033] Mica powder: Use Gree mica powder.

[0034] Maleic anhydride-modified liquid polybutadiene: purchased from Evonik Industries, product model POLYVEST® MA75, which is maleic anhydride-modified low molecular weight 1,4-cis liquid polybutadiene with a viscosity (20℃) of 6000-9000 mPa·s, an acid value of 70-90 mg KOH / g, and a number average molecular weight of approximately 3000 g / mol.

[0035] Preparation Example 1 In a four-necked reactor equipped with a mechanical stirrer, condenser, thermometer, and heating device, 30 parts of maleic anhydride-modified liquid polybutadiene, 5 parts of styrene, 5 parts of carboxyl polybutadiene resin, 1 part of triethoxysilane-modified polybutadiene, and 5 parts of butyl acrylate were added sequentially. The stirrer was turned on and the speed was controlled at 400 rpm to mix evenly. 0.5 parts of a catalyst mixture (composed of ruthenium catalyst, platinum catalyst, and cobalt catalyst in a mass ratio of 3:3:4) were added, and the heating device was turned on to raise the temperature to 130°C and maintain it at 130°C for 3 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, filtered, and a pale yellow, transparent, viscous liquid was obtained, denoted as polyolefin resin A1.

[0036] Preparation Example 2 This preparation example follows the same operational steps as Preparation Example 1, except that: 37 parts of maleic anhydride-modified polybutadiene, 7 parts of styrene, 7 parts of carboxylated polybutadiene resin, 3 parts of triethoxysilane-modified polybutadiene, 7 parts of butyl acrylate, and a catalyst mixture (composed of ruthenium catalyst, platinum catalyst, and cobalt catalyst in a mass ratio of 5:7:10) are added. The reaction temperature is set at 145℃, and the constant temperature reaction time is 4 hours. A pale yellow, transparent, viscous liquid is obtained, denoted as polyolefin resin A2.

[0037] Preparation Example 3 The same operating procedure as in Preparation Example 1 was followed, except that: 45 parts of maleic anhydride-modified polybutadiene, 10 parts of styrene, 10 parts of carboxylated polybutadiene resin, 5 parts of triethoxysilane-modified polybutadiene, and 10 parts of butyl acrylate catalyst mixture (composed of ruthenium catalyst, platinum catalyst, and cobalt catalyst in a mass ratio of 7:7:6) were added. The reaction temperature was set at 160℃, and the constant temperature reaction time was 5 hours. A pale yellow, transparent, viscous liquid was obtained, denoted as polyolefin resin A3.

[0038] Example 1 This embodiment provides an epoxy polyolefin thermosetting coating, the formulation of which (in parts by weight) is as follows: Component A: 50 parts epoxy resin, 20 parts polyolefin resin A1 prepared in Preparation Example 1, 8 parts activated calcium carbonate, 0.5 parts dispersant, 0.3 parts defoamer, 0.2 parts leveling agent, and 50 parts mica powder.

[0039] Component B: 70 parts polyamide resin, 2 parts cobalt isooctanoate catalyst.

[0040] Preparation process: (1) Add epoxy resin, polyolefin resin A1, activated calcium carbonate, dispersant, defoamer, and leveling agent from component A to a high-speed disperser and mix evenly. Then, transfer the mixture to a sand mill and grind it for 30 minutes. After the fineness is qualified, add mica powder under low-speed stirring, disperse it evenly at high speed, and filter to obtain the finished product of component A.

[0041] (2) Mix the polyamide resin and catalyst in component B evenly to obtain component B.

[0042] Application and Curing: Mix component A and component B at a weight ratio of 7:1, apply the mixture to the sandblasted carbon steel substrate using airless spraying, achieve a wet film thickness of 1 mm, and bake at 80℃ for curing.

[0043] Example 2 This embodiment provides an epoxy polyolefin thermosetting coating, the formulation (parts by weight) of which is as follows: Component A: 60 parts epoxy resin, 25 parts polyolefin resin A2 prepared in Preparation Example 2, 10 parts activated calcium carbonate, 0.5 parts dispersant, 0.3 parts defoamer, 0.2 parts leveling agent, and 35 parts mica powder.

[0044] Component B: 75 parts polyamide resin, 6 parts cobalt isooctanoate catalyst.

[0045] Preparation process: Same as in Example 1, with a sanding time of 35 min.

[0046] Application and Curing: Mix component A and component B at a weight ratio of 5:1, apply the mixture to the sandblasted carbon steel substrate using airless spraying, achieve a wet film thickness of 1 mm, and bake at 80℃ for curing.

[0047] Example 3 This embodiment provides an epoxy polyolefin thermosetting coating, the formulation (parts by weight) of which is as follows: Component A: 70 parts epoxy resin, 30 parts polyolefin resin A3 prepared in Preparation Example 3, 13 parts feldspar powder, 0.5 parts dispersant, 0.3 parts defoamer, 0.2 parts leveling agent, and 20 parts mica powder.

[0048] Component B: 80 parts polyamide resin, 10 parts cobalt isooctanoate catalyst.

[0049] Preparation process: Same as in Example 1, with a sanding time of 40 min.

[0050] Application and Curing: Mix component A and component B at a weight ratio of 8:1, apply the mixture to the sandblasted carbon steel substrate using airless spraying, achieve a wet film thickness of 1 mm, and bake and cure at 80℃.

[0051] Comparative Example 1 This comparative example provides a coating whose formulation and process differ from Example 2 only in that: polyolefin resin A2 is not added to component A, and the amount of epoxy resin is increased accordingly to 85 parts.

[0052] Test case The following tests were conducted on Examples 1-3, Comparative Example 1, and commercially available epoxy phenolic coatings, silicone heat-resistant coatings, and polyurethane coatings. The test methods are as follows: Adhesion test: Standards to be followed: Refer to GB / T5210-2006 "Paints and Varnishes - Pull-off Adhesion Test" or ASTM D4541.

[0053] Specific steps: The test column (Dolly) is bonded to the cured coating surface with high-strength epoxy adhesive. After curing at room temperature for 24 hours, an automatic pull-off adhesion tester is used to apply a vertical tensile force until the coating separates from the substrate. The maximum tensile force value (MPa) at the time of breakage is recorded.

[0054] Water boiling adhesion test: Test conditions: 95℃, 168h, deionized water.

[0055] Specific steps: Immerse the prepared sample in a constant temperature water bath containing deionized water, controlling the water temperature at 95±2℃. After soaking for 168 hours, remove the sample, wipe the surface dry with absorbent paper, and place it at room temperature for 2 hours. Then, determine its wet adhesion according to the adhesion test steps described above.

[0056] High-temperature and high-pressure autoclave test: Test conditions: 150℃, 10MPa, deionized water, 168h.

[0057] Specific steps: Place the sample in an autoclave and add deionized water until the sample is completely submerged. Seal the autoclave, heat to 150℃, and pressurize to 10MPa. Maintain this temperature and pressure conditions for 168 hours. After the test, allow it to cool naturally and release the pressure. Remove the sample and visually inspect the coating surface for blistering, cracking, or peeling.

[0058] Acid resistance test Test conditions: 10% sulfuric acid (H2SO4) solution, room temperature, 30 days.

[0059] Specific steps: After sealing the edges of the sample, immerse it in a 10% sulfuric acid solution. Immerse it at room temperature (25±2℃) for 30 days. Remove it, clean and dry it, and observe whether there is discoloration, blistering, rusting or peeling on the coating surface.

[0060] Alkali resistance test Test conditions: 5% sodium hydroxide (NaOH) solution, room temperature, 30 days.

[0061] Specific steps: After sealing the edges of the sample, immerse it in a 5% sodium hydroxide solution. Immerse it at room temperature (25±2℃) for 30 days. Remove it, clean and dry it, and observe whether there is discoloration, blistering or softening on the coating surface.

[0062] The test results are shown in Table 1.

[0063] Table 1. Performance test results of Examples 1-3, comparative examples, and commercially available products.

[0064] According to data comparison, the performance is significantly better after adding polyolefins than without them, and the resistance is significantly improved under high temperature and strong acid conditions.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy polyolefin thermosetting coating, comprising component A and component B, characterized in that, The raw materials of component A, by weight, include: 50-70 parts epoxy resin, 20-30 parts polyolefin resin, 10-15 parts auxiliary additives, and 20-50 parts mica powder. The raw materials of component B, by weight, include: 70-80 parts of polyamide resin and 2-10 parts of catalyst.

2. The epoxy polyolefin thermosetting coating according to claim 1, characterized in that, The polyolefin resin is prepared by reacting maleic anhydride-modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane-modified polybutadiene, and butyl acrylate. The mass ratio of the maleic anhydride-modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane-modified polybutadiene, and butyl acrylate is (30-45):(5-10):(5-10):(1-5):(5-10). The auxiliary additives include active calcium carbonate and / or feldspar powder.

3. The epoxy polyolefin thermosetting coating according to claim 1, characterized in that, The catalyst in component B is a transition metal catalyst; the transition metal catalyst includes ruthenium catalyst, platinum catalyst and cobalt catalyst, and the mass ratio of the three is (20-35):(20-40):(35-45).

4. A method for preparing the epoxy polyolefin thermosetting coating according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Preparation of component A: Mix epoxy resin, polyolefin resin and auxiliary additives evenly, grind them, and then add mica powder and mix evenly. (2) Preparation of component B: Mix the polyamide resin and catalyst and stir evenly.

5. The preparation method according to claim 4, characterized in that, The preparation process of the polyolefin resin in step (1) is as follows: maleic anhydride modified polybutadiene, styrene, carboxylated polybutadiene resin, triethoxysilane modified polybutadiene and butyl acrylate are mixed and heated to 130℃-160℃ under catalytic conditions, and reacted for 3-5 hours.

6. The preparation method according to claim 5, characterized in that, In step (1), the grinding time is 30-40 minutes.

7. The preparation method according to claim 4, characterized in that, In step (1), the mica powder is added after the epoxy resin, polyolefin resin and auxiliary additives are mixed and milled.

8. The application of the epoxy polyolefin thermosetting coating according to any one of claims 1-3, characterized in that, During construction, component A and component B are mixed and sprayed onto the surface of the substrate, with the mass ratio of component A to component B being 5-8:

1.

9. The application according to claim 8, characterized in that, Before spraying, the steel surface is sandblasted according to the SSPC SP10 standard.

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