Antistatic polyurea coating and method for its preparation

Abstract

The application provides an antistatic polyurea coating and a preparation method thereof. The polyurea coating comprises the following components in parts by weight: polyaspartic ester resin 30-50 parts, isocyanate composition 25-40 parts, composite antistatic agent 5-10 parts, stabilizer 0.5-2 parts, chain extender 2-8 parts, dispersing agent 0.2-1 part, and defoaming agent 0.2-1 part. The polyurea coating prepared by the application has low surface resistivity, minimum spindle rod diameter and high oxygen index, indicating that the antistatic performance, mechanical property and flame retardant property are good, and the preparation process is simple, suitable for industrial production, and has important application value.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and particularly relates to an antistatic polyurea coating and its preparation method. Background Technology

[0002] Polyurea coatings are widely used in the construction, transportation, chemical, and electronics industries for floor, wall, and equipment protection due to their excellent abrasion resistance, corrosion resistance, high strength, and rapid curing properties. However, traditional polyurea coatings are typically insulating materials with high surface resistivity (generally greater than 10 Ω·cm). 12 (Ω), which easily accumulates static charge during use, leading to electrostatic discharge, and does not meet the application requirements for anti-static applications such as electronic cleanrooms, petrochemical storage tanks, and mining equipment.

[0003] Currently, the main methods to improve the antistatic properties of polyurea coatings are to add conductive fillers (such as carbon black, metal powder, etc.) or conductive polymers. However, single conductive fillers are often added in large quantities, which can affect the flexibility, adhesion, and appearance of the coating film; while conventional conductive polymers have problems such as rapid migration, poor durability of antistatic effects, and significant performance degradation after long-term use. In addition, existing antistatic polyurea coatings are difficult to meet the requirements of complex environments that require both fire resistance and antistatic properties.

[0004] Therefore, how to develop a polyurea coating with good antistatic properties, good mechanical properties, and superior flame retardant properties is a problem that this invention urgently needs to solve. Summary of the Invention

[0005] The purpose of this invention is to provide an antistatic polyurea coating and its preparation method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides an antistatic polyurea coating, characterized in that the polyurea coating comprises the following components in parts by weight: 30-50 parts of polyaspartic acid ester resin, 25-40 parts of isocyanate composition, 5-10 parts of composite antistatic agent, 0.5-2 parts of stabilizer, 2-8 parts of chain extender, 0.2-1 parts of dispersant, and 0.2-1 parts of defoamer; The composite antistatic agent is a combination of a polyoxyethylene ether type antistatic agent and modified conductive mica.

[0007] As a further improvement, the synthesis of the polyoxyethylene ether type antistatic agent includes the following steps: (1) Add octylphenol polyoxyethylene ether to a flask, then add organic solvent and catalyst in sequence, stir and mix for 10-30 min under ice bath conditions, then add 3-butenoyl chloride dropwise into the mixture, stir and react at room temperature for 10-15 h, after the reaction is completed, and then perform post-treatment to obtain intermediate one. (2) Under a nitrogen atmosphere, deionized water, initiator, intermediate one and dimethylaminoethyl methacrylate were added to the flask in sequence. The reaction was carried out at 70-80℃ for 12-15h. After the reaction was completed, the product was post-processed to obtain a polyoxyethylene ether type antistatic agent.

[0008] As a further improvement, the octylphenol polyoxyethylene ether in step (1) is either OP-4 or OP-7.

[0009] For better compatibility, the octylphenol polyoxyethylene ether is preferably OP-4.

[0010] As a further improvement, the modified conductive mica is a conductive mica modified with a phthalate coupling agent.

[0011] As a further improvement, the preparation of the modified conductive mica includes the following steps: The titanate coupling agent was dissolved in anhydrous ethanol to obtain a mixed solution of titanate coupling agent. The mixed solution of titanate coupling agent and conductive mica powder were added to a flask and stirred at 50-60℃ for 2-5 hours. After mixing, the mixture was post-treated to obtain modified conductive mica.

[0012] As a further improvement, the titanate coupling agent is bis(dioctylpyrophosphate)ethylene titanate.

[0013] As a further improvement, the mass ratio of the polyoxyethylene ether type antistatic agent to the modified conductive mica is 1:2-4.

[0014] As a further improvement, the amine value of the polyaspartic acid ester resin is 210-260 mg KOH / g.

[0015] As a further improvement, the isocyanate composition is a combination of any one of isophorone diisocyanate and hexamethylene diisocyanate with HDI trimer.

[0016] Preferably, the isocyanate composition is a combination of isophorone diisocyanate and HDI trimer; more preferably, the mass ratio of isophorone diisocyanate to HDI trimer is 3-5:1.

[0017] The multifunctionality of HDI trimer can form a uniform cross-linked network, and it has strong interfacial bonding with polyaspartic acid ester resin and modified conductive mica, which can improve the wear resistance and toughness of coating films to a certain extent.

[0018] As a further improvement, the chain extender is at least one selected from ethylenediamine, trimethylhexanediamine, diethyltoluenediamine, and diethanolamine.

[0019] Preferably, the chain extender is trimethylhexanediamine.

[0020] As a further improvement, the stabilizer is at least one of antioxidant 1010 and antioxidant 1076; for better anti-aging effect, antioxidant 1010 is preferred.

[0021] As a further improvement, the dispersant is a polycarboxylate dispersant, more preferably BYK-110; the defoamer is an organosilicon defoamer, more preferably BYK-066N.

[0022] This invention also provides a method for preparing an antistatic polyurea coating, characterized by comprising the following steps: (1) Add polyaspartic acid ester resin, stabilizer, dispersant and defoamer to the reaction vessel according to the weight parts and stir to mix. Then add composite antistatic agent and continue to mix evenly to obtain a premixed system. (2) Add chain extender and isocyanate composition to the premixed system of step (1) in sequence, mix evenly, and the antistatic polyurea coating is obtained.

[0023] Compared with the prior art, the beneficial effects of the present invention are: This invention provides an antistatic polyurea coating and its preparation method. The obtained polyurea coating has lower surface resistivity, minimum shaft diameter, and higher oxygen index, indicating good antistatic properties, high flexibility, and good flame retardant properties. This invention improves the dispersibility and compatibility of conductive mica powder with the resin matrix by preparing phthalate coupling agents to modify conductive mica. Combined with the prepared polyoxyethylene ether-type antistatic agent, this further enhances the antistatic properties of polyurea coatings. The phthalate coupling agent-modified conductive mica, as a conductive filler, also improves the compatibility with polyaspartic acid ester resin and isocyanate compositions to a certain extent, resulting in better flexibility of the coating, allowing it to adapt to slight deformation of the substrate and reducing the likelihood of cracking and peeling. Furthermore, the polyoxyethylene ether-type antistatic agent prepared in this invention contains a structure similar to phosphorus-based flame retardants, which further improves the flame retardant properties of polyurea coatings and broadens their application scenarios. Detailed Implementation

[0024] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0025] In the following examples, except for the polyoxyethylene ether type antistatic agent, modified conductive mica 1, and modified conductive mica 2, all other compound monomers and related reagents used can be purchased from the market. Among them, octylphenol polyoxyethylene ether was purchased from Nantong Boya Environmental Protection Technology Co., Ltd., model OP-4; conductive mica was purchased from Hebei Jiegui Mineral Products Co., Ltd.; polyaspartic acid ester resin was purchased from Quzhou Deyu Technology Co., Ltd., model JH-8122; HDI trimer was purchased from Jinan Anying Trading Co., Ltd., model HT-100; and silicone defoamer and polycarboxylate dispersant were purchased from Shanghai Mengdihu Industrial Co., Ltd., models BYK-066N and BYK-110, respectively.

[0026] The synthesis of polyoxyethylene ether type antistatic agents includes the following steps: (1) Add 20.3g of octylphenol polyoxyethylene ether to a flask, then add 200mL of dichloromethane, 12mL of triethylamine and 0.8g of cuprous chloride in sequence. Stir and mix for 15min under ice bath conditions. Then add 10.5g of 3-butenoyl chloride dropwise to the mixture. Stir and react at room temperature for 12h. After the reaction is completed, filter and evaporate the filtrate by rotary evaporation. Separate by column chromatography to obtain intermediate one. (2) Under a nitrogen atmosphere, 100 mL of deionized water, 0.5 g of potassium persulfate, 4.5 g of intermediate I, and 3.1 g of dimethylaminoethyl methacrylate were added to the flask in sequence. The reaction was carried out at 80 °C for 15 h. After the reaction was completed, the mixture was filtered and washed with methanol. The mixture was dried at 70 °C to obtain a polyoxyethylene ether type antistatic agent.

[0027] The synthesis of modified conductive mica 1 includes the following steps: 10g of titanate coupling agent was dissolved in 300mL of anhydrous ethanol to obtain a mixed solution of titanate coupling agent. 100mL of the mixed solution of titanate coupling agent and 200g of conductive mica powder were added to a flask and stirred at 60℃ for 3h. The solvent was removed by vacuum distillation and then dried at 90℃ for 12h to obtain modified conductive mica 1.

[0028] The synthesis of modified conductive mica 2 includes the following steps: 10g of γ-aminopropyltriethoxysilane was dissolved in 250mL of anhydrous ethanol to obtain a silane coupling agent mixed solution. 100mL of the silane coupling agent mixed solution and 200g of conductive mica powder were added to a flask and stirred at 60℃ for 3h. The solvent was removed by vacuum distillation and then dried at 90℃ for 12h to obtain modified conductive mica 2.

[0029] The preparation methods of Examples 1-3 and Comparative Examples 1-4 include the following steps: (1) Add polyaspartic acid ester resin, stabilizer, dispersant and defoamer to the reaction vessel according to the weight parts and stir to mix. Then add composite antistatic agent and continue to mix evenly to obtain a premixed system. (2) Add chain extender and isocyanate composition to the premixed system of step (1) in sequence, mix evenly, and the antistatic polyurea coating is obtained.

[0030] The components and their contents used in Examples 1-3 and Comparative Examples 1-4 are shown in Table 1 below: Table 1

[0031] The polyurea coatings prepared in Examples 1-3 and Comparative Examples 1-4 were applied to steel plates using a coating scraper, with the film thickness controlled at 300 μm. After curing at room temperature for 7 days, the resulting film was obtained, and its surface resistivity and flexibility were then tested. Alternatively, the polyurea coating was poured into a flat silicone mold, with the thickness controlled at 3 mm, and cured at room temperature for 7 days. The oxygen index was then tested using the following methods: Surface resistivity: determined according to GB / T 31838.3-2019; Flexibility: According to GB / T 1731-2020, it is expressed as the smallest shaft diameter (mm) that does not cause damage to the paint film. The smaller the diameter, the better the flexibility. Oxygen index: determined according to GB / T 2406.2-2009.

[0032] Table 2

[0033] As can be seen from the test results in Table 2, the polyurea coating prepared by the method provided by this invention has a lower surface resistivity, a smaller shaft diameter, and a higher oxygen index. This indicates that by preparing a polyoxyethylene ether-type antistatic agent and phthalate coupling agent to modify conductive mica, the synergistic effect of the two as a composite antistatic agent can improve the antistatic performance of the polyurea coating. The compatibility and dispersibility between the components are good, resulting in good flexibility of the coating film after formation. The use of the polyoxyethylene ether-type antistatic agent improves the flame retardancy of the coating to a certain extent. The preparation process of the polyurea coating of this invention is simple and suitable for industrial production.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An antistatic polyurea coating, characterized in that, The polyurea coating comprises the following components in parts by weight: 30-50 parts of polyaspartic ester resin, 25-40 parts of isocyanate composition, 5-10 parts of composite antistatic agent, 0.5-2 parts of stabilizer, 2-8 parts of chain extender, 0.2-1 parts of dispersant, and 0.2-1 parts of defoamer; The composite antistatic agent is a combination of a polyoxyethylene ether type antistatic agent and modified conductive mica.

2. The antistatic polyurea coating according to claim 1, characterized in that, The synthesis of the polyoxyethylene ether type antistatic agent includes the following steps: (1) Add octylphenol polyoxyethylene ether to a flask, then add organic solvent and catalyst in sequence, stir and mix for 10-30 min under ice bath conditions, then add 3-butenoyl chloride dropwise into the mixture, stir and react at room temperature for 10-15 h, after the reaction is completed, and then perform post-treatment to obtain intermediate one. (2) Under a nitrogen atmosphere, deionized water, initiator, intermediate one and dimethylaminoethyl methacrylate were added to the flask in sequence. The reaction was carried out at 70-80℃ for 12-15h. After the reaction was completed, the product was post-processed to obtain a polyoxyethylene ether type antistatic agent.

3. The antistatic polyurea coating according to claim 2, characterized in that, In step (1), the octylphenol polyoxyethylene ether is either OP-4 or OP-7.

4. The antistatic polyurea coating according to claim 1, characterized in that, The modified conductive mica is a conductive mica modified with phthalate coupling agent.

5. The antistatic polyurea coating according to claim 1, characterized in that, The preparation of the modified conductive mica includes the following steps: The titanate coupling agent was dissolved in anhydrous ethanol to obtain a mixed solution of titanate coupling agent. The mixed solution of titanate coupling agent and conductive mica powder were added to a flask and stirred at 50-60℃ for 2-5 hours. After mixing, the mixture was post-treated to obtain modified conductive mica.

6. The antistatic polyurea coating according to claim 1, characterized in that, The mass ratio of the polyoxyethylene ether type antistatic agent to the modified conductive mica is 1:2-4.

7. The antistatic polyurea coating according to claim 1, characterized in that, The amine value of the polyaspartic acid ester resin is 210-260 mg KOH / g.

8. The antistatic polyurea coating according to claim 1, characterized in that, The isocyanate composition is a combination of any one of isophorone diisocyanate and hexamethylene diisocyanate with HDI trimer.

9. The antistatic polyurea coating according to claim 1, characterized in that, The chain extender is at least one of ethylenediamine, trimethylhexanediamine, diethyltoluenediamine, and diethanolamine.

10. A method for preparing an antistatic polyurea coating according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Add polyaspartic acid ester resin, stabilizer, dispersant and defoamer to the reaction vessel according to the weight parts and stir to mix. Then add composite antistatic agent and continue to mix evenly to obtain a premixed system. (2) Add chain extender and isocyanate composition to the premixed system of step (1) in sequence, mix evenly, and the antistatic polyurea coating is obtained.

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