Modified polyurea coating

Abstract

The invention relates to the technical field of coatings, in particular to a modified polyurea coating which is characterized by comprising a component A prepolymer and a component B prepolymer, the component A prepolymer is prepared from the following components in parts by weight: 20 parts of a hydroxyl-terminated compound, 50 to 80 parts of hexamethylene diisocyanate, 6 to 9 parts of an N-dimethyl-N-carboxymethyl ammonium chloride dispersing agent and 20 to 30 parts of benzoyl chloride; the component B prepolymer comprises the following components in parts by weight: 40 parts of amino-terminated resin, 1-3 parts of an amino-terminated chain extender and 40-50 parts of high-purity aminated graphene oxide powder; according to the modified polyurea coating disclosed by the invention, the hexamethylene diisocyanate tripolymer compound has the characteristics of good yellowing resistance, stable structure and difficulty in dissolving at high temperature, so that the modified polyurea coating has better wear resistance, corrosion resistance and thermal stability; through high flexibility, high strength and good thermal conductivity of the high-purity aminated graphene oxide powder, the flexibility, the structural strength and the heat dissipation performance of the modified polyurea coating can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a modified polyurea coating. Background Art

[0002] Polyurea coating is a new type of environmentally friendly coating developed to meet environmental protection needs. It is a two-component, solvent-free, fast-curing elastic material, in which component A prepolymer is a semi-prepolymer made by the reaction of terminal hydroxyl compounds and isocyanates, and component B prepolymer is a mixture of terminal amino resin and terminal amino chain extender. It does not contain any hydroxyl components and catalysts, but is allowed to contain a small amount of pigments and dispersing aids. Component A prepolymer and component B prepolymer are mixed in the spray gun of special spraying equipment and then sprayed out, and quickly react and cure to form an elastomeric waterproof film; the coating is insensitive to water and moisture, is less affected by ambient temperature and humidity, and has excellent physical properties. It can be widely used in metal (non-metal) anti-corrosion and waterproof coating fields in industries such as oil pipelines, refining and chemical industry, power equipment, bridge engineering, ship protection, marine facilities, airport runways, sewage treatment, subways, tunnels, and power plant desulfurization.

[0003] In order to improve the performance and application scope of polyurea coatings, polyurea coatings are modified with nano materials. Nano-modified polyurea coatings are prepared by adding different nano materials to polyurea coatings so as to improve one or several physical and chemical properties of polyurea coatings in a targeted manner. Some existing polyurea coatings have some problems during use: first, when existing polyurea coatings are used in oil pipelines or sewage treatment fields, the environment contains various corrosive acidic and alkaline substances, which will corrode the coating surface, and the existing polyurea coatings are not corrosion resistant enough; second, when existing polyurea coatings are used in oil pipelines or sewage treatment fields, the ambient temperature may be high, and the existing polyurea coatings are not heat-dissipating and thermally stable enough. Therefore, a modified polyurea coating is proposed to address the above problems. Summary of the invention

[0004] The object of the present invention is to provide a modified polyurea coating to solve the problems of insufficient corrosion resistance, heat dissipation and thermal stability of the existing polyurea coating when it is used in the field of petroleum pipelines or sewage treatment.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A modified polyurea coating, characterized in that it comprises a component A prepolymer and a component B prepolymer; in parts by weight, the content of each component in the component A prepolymer is: 20 parts of terminal hydroxyl compound, 50-80 parts of hexamethylene diisocyanate, 6-9 parts of N-dimethyl-N-carboxymethyl ammonium chloride dispersant, and 20-30 parts of benzoyl chloride; the content of each component in the component B prepolymer is: 40 parts of terminal amino resin, 1-3 parts of terminal amino chain extender, and 40-50 parts of high-purity amino-treated graphene oxide powder.

[0007] Preferably, the high-purity aminated graphene oxide powder is prepared according to the following steps:

[0008] S1) mixing graphene oxide oxygen powder and dimethylformamide uniformly to obtain a suspension of graphene oxide oxygen powder and dimethylformamide, wherein the mass ratio of the graphene oxide oxygen powder to the dimethylformamide is 1:15-300;

[0009] S2) mixing tetrahydrofuran and N,N'-dicyclohexylcarbodiimide uniformly to obtain a tetrahydrofuran solution of N,N'-dicyclohexylcarbodiimide, wherein the mass ratio of tetrahydrofuran to N,N'-dicyclohexylcarbodiimide is 5:1-10:1;

[0010] S3) adding the tetrahydrofuran solution of N,N'-dicyclohexylcarbodiimide to a suspension of graphene oxide powder and dimethylformamide, and then adding ethylenediamine to the suspension of graphene oxide powder and dimethylformamide to obtain a reaction solution, wherein the mass ratio of ethylenediamine to N,N'-dicyclohexylcarbodiimide is 1:1;

[0011] S4) stirring the reaction solution for 3-5 d and filtering with suction to obtain an amination-modified graphene oxide powder with certain impurities;

[0012] S5) washing the aminated graphene oxide powder with certain impurities for multiple times with methanol, and then washing the aminated graphene oxide powder with certain impurities for multiple times with distilled water to remove residual organic matter during the operation, so as to obtain high-purity aminated graphene oxide powder.

[0013] Preferably, the A component prepolymer is prepared according to the following steps:

[0014] S1) adding 20 parts of the terminal hydroxyl compound and 6-9 parts of N-dimethyl-N-carboxymethyl ammonium chloride dispersant into a reactor, closing the reactor, and filling the reactor with nitrogen to discharge air;

[0015] S2) starting the reaction kettle for high-speed stirring and heating at the same time, the heating temperature is 36-48° C., after 6-8 minutes, 50-80 parts of the hexamethylene diisocyanate are dropwise added into the reaction kettle, and heating and stirring are continued to cause the hexamethylene diisocyanate to undergo a trimerization reaction to generate a hexamethylene diisocyanate trimer;

[0016] S3) 30-40 minutes later, adding 20-30 parts of the benzoyl chloride into the reactor, continuing the reaction for 20-30 minutes, and the trimerization reaction is terminated. At this time, the trimerization reaction generates a mixture containing a large amount of the hexamethylene diisocyanate trimer compound and a small amount of the hexamethylene diisocyanate pentamer compound and a small amount of the hexamethylene diisocyanate heptamer compound;

[0017] S4) raising the temperature of the reaction kettle to 110-126° C. and continuously evacuating the reactor for 2-3 hours to remove small molecule water and residual monomers to obtain a prepolymer of component A.

[0018] Preferably, the B component prepolymer is prepared according to the following steps:

[0019] S1) adding 40 parts of amino-terminated resin, 1-3 parts of amino-terminated chain extender, and 40-50 parts of high-purity amino-terminated graphene oxide powder into a reactor, and then adding acetone into the reactor, wherein the weight of acetone is twice the total weight of the above components, to obtain a solution mixture;

[0020] S2) starting the reactor to stir and heat at the same time, the heating temperature is 50-60° C.;

[0021] S3) After 20-30 minutes, the temperature of the reaction kettle is raised to 90-98°C, and vacuum is continuously drawn for 2-3 hours to remove acetone to obtain a prepolymer of component B.

[0022] Preferably, the A component prepolymer and the B component prepolymer need to be stored separately after preparation. When using the coating, the A component prepolymer and the B component prepolymer are respectively charged into the spray gun of a special spraying equipment, and the special spraying equipment mixes and sprays the A component prepolymer and the B component prepolymer through the spray gun. The A component prepolymer and the B component prepolymer react and solidify quickly to form an elastomeric waterproof film. The solidification time of the A component prepolymer and the B component prepolymer is 12-22s.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In the present invention, hexamethylene diisocyanate (HDI) undergoes a trimerization reaction under heating catalytic conditions, and the trimerization reaction is terminated by benzoyl chloride to obtain a large amount of hexamethylene diisocyanate trimer compound and a small amount of hexamethylene diisocyanate pentamer compound and a small amount of hexamethylene diisocyanate heptamer compound. The hexamethylene diisocyanate trimer compound is an aliphatic compound, does not contain easily oxidizable groups such as benzene rings, has good yellowing resistance, and has a stable structure and is not easily decomposed at high temperatures. It can make the modified polyurea coating have better wear resistance, corrosion resistance and thermal stability. In the present invention, the oxide stone The graphene oxide powder is modified by a chemical method. The modified and purified high-purity aminated graphene oxide powder has a high steric effect, and therefore has good dispersibility and fluidity. The high-purity aminated graphene oxide powder can be stably and evenly distributed in the solvent and composite material matrix for a long time, and the high-purity aminated graphene oxide powder can play a role in chain extension and cross-linking, which can further improve the stability of the nanomaterial in the matrix resin. At the same time, the high-purity aminated graphene oxide powder has high flexibility, high strength and good thermal conductivity, which can significantly improve the flexibility, structural strength and heat dissipation of the modified polyurea coating. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a technical solution:

[0027] A modified polyurea coating, characterized in that it comprises a prepolymer of component A and a prepolymer of component B; in terms of weight, the content of each component in the prepolymer of component A is: 20 parts of terminal hydroxyl compound, 50-80 parts of hexamethylene diisocyanate, 6-9 parts of N-dimethyl-N-carboxymethyl ammonium chloride dispersant, and 20-30 parts of benzoyl chloride; the content of each component in the prepolymer of component B is: 40 parts of terminal amino resin, 1-3 parts of terminal amino chain extender, and 40-50 parts of high-purity amino-modified graphene oxide powder;

[0028] Furthermore, high-purity amino-modified graphene oxide powder is prepared according to the following steps: first, graphene oxide oxygen powder and dimethylformamide are mixed evenly to obtain a suspension of graphene oxide oxygen powder and dimethylformamide, wherein the mass ratio of graphene oxide oxygen powder to dimethylformamide is 1:15-300; then, tetrahydrofuran and N, N'-dicyclohexylcarbodiimide are mixed evenly to obtain a tetrahydrofuran solution of N, N'-dicyclohexylcarbodiimide, wherein the mass ratio of tetrahydrofuran to N, N'-dicyclohexylcarbodiimide is 5:1-10:1; then, the tetrahydrofuran solution of N, N'-dicyclohexylcarbodiimide is added to the graphene oxide; The method comprises the following steps: adding ethylenediamine to a suspension of graphene oxide powder and dimethylformamide, and then adding ethylenediamine to the suspension of graphene oxide powder and dimethylformamide to obtain a reaction solution, wherein the mass ratio of ethylenediamine to N, N'-dicyclohexylcarbodiimide is 1:1, and then stirring the reaction solution for 3-5 days and filtering to obtain amino graphene oxide powder with certain impurities, and finally washing the amino graphene oxide powder with certain impurities with methanol for multiple times, and then washing the amino graphene oxide powder with certain impurities with distilled water for multiple times to remove residual organic matter in the operation process, so as to obtain high-purity amino graphene oxide powder.

[0029] Furthermore, the prepolymer of component A is prepared according to the following steps: first, 20 parts of the terminal hydroxyl compound and 6-9 parts of the N-dimethyl-N-carboxymethyl ammonium chloride dispersant are added into a reactor, the reactor is closed, nitrogen is filled into the reactor to exhaust the air, and then the reactor is started for high-speed stirring and heating at the same time, the heating temperature is 36-48° C. After 6-8 minutes, 50-80 parts of hexamethylene diisocyanate are added dropwise into the reactor, and heating and stirring are continued to cause the hexamethylene diisocyanate to undergo a trimerization reaction to generate hexamethylene diisocyanate. Isocyanate trimer; after waiting for 30-40 minutes, add 20-30 parts of benzoyl chloride into the reactor, continue to react for 20-30 minutes, and the trimerization reaction is terminated. At this time, the trimerization reaction generates a mixture containing more hexamethylene diisocyanate trimer compounds and a small amount of hexamethylene diisocyanate pentamer compounds and a small amount of hexamethylene diisocyanate heptamer compounds. Finally, the temperature of the reactor is increased to 110-126°C, and vacuum is continuously drawn for 2-3 hours to remove small molecular water and residual monomers to obtain component A prepolymer.

[0030] Furthermore, the B component prepolymer is prepared according to the following steps: first, 40 parts of terminal amino resin, 1-3 parts of terminal amino chain extender, and 40-50 parts of high-purity amino-modified graphene oxide powder are added into a reactor, and then acetone is added into the reactor, wherein the weight of acetone is twice the total weight of the above components, to obtain a solution mixture, and then the reactor is started for stirring and heating at the same time, and the heating temperature is 50-60°C. After waiting for 20-30 minutes, the temperature of the reactor is raised to 90-98°C, and vacuum is continuously drawn for 2-3 hours to remove acetone to obtain the B component prepolymer.

[0031] Furthermore, after the preparation of the A component prepolymer and the B component prepolymer is completed, it is necessary to store them separately. When using the coating, the A component prepolymer and the B component prepolymer are respectively charged into the spray gun of the special spraying equipment. The special spraying equipment mixes and sprays the A component prepolymer and the B component prepolymer through the spray gun. The A component prepolymer and the B component prepolymer react and solidify quickly to form an elastomeric waterproof film. The solidification time of the A component prepolymer and the B component prepolymer is 12-22s.

[0032] Workflow: In the first step, high-purity amino-modified graphene oxide powder needs to be prepared. The high-purity amino-modified graphene oxide powder is prepared according to the following steps: first, the graphene oxide oxygen powder and dimethylformamide are evenly mixed to obtain a suspension of graphene oxide oxygen powder and dimethylformamide, and the mass ratio of graphene oxide oxygen powder to dimethylformamide is 1:15-300; then, tetrahydrofuran and N, N'-dicyclohexylcarbodiimide are evenly mixed to obtain a tetrahydrofuran solution of N, N'-dicyclohexylcarbodiimide, and the mass ratio of tetrahydrofuran to N, N'-dicyclohexylcarbodiimide is 5:1-10. : 1, then adding a tetrahydrofuran solution of N, N'-dicyclohexylcarbodiimide to a suspension of graphene oxide powder and dimethylformamide, then adding ethylenediamine to the suspension of graphene oxide powder and dimethylformamide to obtain a reaction solution, wherein the mass ratio of ethylenediamine to N, N'-dicyclohexylcarbodiimide is 1:1, then stirring the reaction solution for 3-5 days and filtering to obtain amino graphene oxide powder with certain impurities, finally washing the amino graphene oxide powder with certain impurities with methanol for multiple times, and then washing the amino graphene oxide powder with certain impurities with distilled water. The reaction mixture is washed several times to remove residual organic matter during the operation to obtain high-purity amino-modified graphene oxide powder. The second step is to prepare a prepolymer of component A. The prepolymer of component A is prepared according to the following steps: first, 20 parts of a terminal hydroxyl compound and 6-9 parts of an N-dimethyl-N-carboxymethyl ammonium chloride dispersant are added to a reactor, the reactor is closed, nitrogen is filled into the reactor to exhaust the air, and then the reactor is started for high-speed stirring and heating at the same time. The heating temperature is 36-48°C. After 6-8 minutes, 50-80 parts of hexamethylene diisocyanate are added dropwise to the reactor, and heating and stirring are continued. Stirring to allow hexamethylene diisocyanate to undergo a trimerization reaction to generate hexamethylene diisocyanate trimer; after waiting for 30-40 minutes, adding 20-30 parts of benzoyl chloride into the reactor, continuing the reaction for 20-30 minutes, the trimerization reaction terminates, at which time the trimerization reaction generates a mixture containing a large amount of hexamethylene diisocyanate trimer compound and a small amount of hexamethylene diisocyanate pentamer compound and a small amount of hexamethylene diisocyanate heptamer compound; finally, raising the temperature of the reactor to 110-126° C., continuously evacuating the reactor for 2-3 hours, removing small molecular water and residual monomers, and obtaining a prepolymer of component A;The third step is to prepare the prepolymer of component B. The prepolymer of component B is prepared according to the following steps: first, 40 parts of terminal amino resin, 1-3 parts of terminal amino chain extender, and 40-50 parts of high-purity amino-modified graphene oxide powder are added into the reactor, and then acetone is added into the reactor. The weight of acetone is twice the total weight of the above components to obtain a solution mixture, and then the reactor is started to stir and heat at the same time. The heating temperature is 50-60°C. After waiting for 20-30 minutes, the temperature of the reactor is raised to 90-98°C, and vacuum is continuously drawn for 2-3 hours to remove the mixture. The acetone is removed to obtain a prepolymer of component B; the fourth step is to store the prepolymer of component A and the prepolymer of component B separately after preparation; when using the coating, the prepolymer of component A and the prepolymer of component B are respectively charged into the spray gun of a special spraying device, and the special spraying device mixes and sprays the prepolymer of component A and the prepolymer of component B through the spray gun, and the prepolymer of component A and the prepolymer of component B react and solidify quickly to form an elastomeric waterproof film, and the solidification time of the prepolymer of component A and the prepolymer of component B is 12-22s; in the present invention, hexamethylene diisocyanate (HDI) is heated and catalyzed to generate a waterproof film; The trimerization reaction is terminated by benzoyl chloride to obtain a large amount of hexamethylene diisocyanate trimer compound and a small amount of hexamethylene diisocyanate pentamer compound and a small amount of hexamethylene diisocyanate heptamer compound. The hexamethylene diisocyanate trimer compound belongs to an aliphatic compound, does not contain easily oxidizable groups such as benzene rings, has good yellowing resistance, and has a stable structure and is not easy to decompose at high temperatures. It can make the modified polyurea coating have better wear resistance, corrosion resistance and thermal stability; in the present invention, the graphene oxide powder is modified by a chemical method The modified and purified high-purity aminated graphene oxide powder has a high steric effect, so it has good dispersibility and fluidity. The high-purity aminated graphene oxide powder can be stably and evenly distributed in the solvent and composite matrix for a long time, and the high-purity aminated graphene oxide powder can play a role in chain extension and cross-linking, which can further improve the stability of nanomaterials in the matrix resin. At the same time, the high-purity aminated graphene oxide powder has high flexibility, high strength and good thermal conductivity, which can significantly improve the flexibility, structural strength and heat dissipation of the modified polyurea coating. ;

[0033] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A modified polyurea coating, comprising a prepolymer of component A and a prepolymer of component B, characterized in that: In parts by weight, the contents of each component in the prepolymer of component A are: 20 parts of terminal hydroxyl compound, 50-80 parts of hexamethylene diisocyanate, 6-9 parts of N-dimethyl-N-carboxymethyl ammonium chloride dispersant, and 20-30 parts of benzoyl chloride; the contents of each component in the prepolymer of component B are: 40 parts of terminal amino resin, 1-3 parts of terminal amino chain extender, and 40-50 parts of high-purity amino-modified graphene oxide powder.

2. A modified polyurea coating according to claim 1, characterized in that: The high-purity aminated graphene oxide powder is prepared according to the following steps: S1) mixing graphene oxide oxygen powder and dimethylformamide uniformly to obtain a suspension of graphene oxide oxygen powder and dimethylformamide, wherein the mass ratio of the graphene oxide oxygen powder to the dimethylformamide is 1:15-300; S2) mixing tetrahydrofuran and N,N'-dicyclohexylcarbodiimide uniformly to obtain a tetrahydrofuran solution of N,N'-dicyclohexylcarbodiimide, wherein the mass ratio of tetrahydrofuran to N,N'-dicyclohexylcarbodiimide is 5:1-10:1; S3) adding the tetrahydrofuran solution of N,N'-dicyclohexylcarbodiimide to a suspension of graphene oxide powder and dimethylformamide, and then adding ethylenediamine to the suspension of graphene oxide powder and dimethylformamide to obtain a reaction solution, wherein the mass ratio of ethylenediamine to N,N'-dicyclohexylcarbodiimide is 1:1; S4) stirring the reaction solution for 3-5 d and filtering with suction to obtain an amination-modified graphene oxide powder with certain impurities; S5) washing the aminated graphene oxide powder with certain impurities for multiple times with methanol, and then washing the aminated graphene oxide powder with certain impurities for multiple times with distilled water to remove residual organic matter during the operation, so as to obtain high-purity aminated graphene oxide powder.

3. A modified polyurea coating according to claim 1, characterized in that: The A component prepolymer is prepared according to the following steps: S1) adding 20 parts of the terminal hydroxyl compound and 6-9 parts of N-dimethyl-N-carboxymethyl ammonium chloride dispersant into a reactor, closing the reactor, and filling the reactor with nitrogen to discharge air; S2) starting the reaction kettle for high-speed stirring and heating at the same time, the heating temperature is 36-48° C., after 6-8 minutes, 50-80 parts of the hexamethylene diisocyanate are dropwise added into the reaction kettle, and heating and stirring are continued to cause the hexamethylene diisocyanate to undergo a trimerization reaction to generate a hexamethylene diisocyanate trimer; S3) 30-40 minutes later, adding 20-30 parts of the benzoyl chloride into the reactor, continuing the reaction for 20-30 minutes, and the trimerization reaction is terminated. At this time, the trimerization reaction generates a mixture containing a large amount of the hexamethylene diisocyanate trimer compound and a small amount of the hexamethylene diisocyanate pentamer compound and a small amount of the hexamethylene diisocyanate heptamer compound; S4) raising the temperature of the reaction kettle to 110-126° C. and continuously evacuating the reactor for 2-3 hours to remove small molecule water and residual monomers to obtain a prepolymer of component A.

4. A modified polyurea coating according to claim 1, characterized in that: The B component prepolymer is prepared according to the following steps: S1) adding 40 parts of amino-terminated resin, 1-3 parts of amino-terminated chain extender, and 40-50 parts of high-purity amino-terminated graphene oxide powder into a reactor, and then adding acetone into the reactor, wherein the weight of acetone is twice the total weight of the above components, to obtain a solution mixture; S2) starting the reactor to stir and heat at the same time, the heating temperature is 50-60° C.; S3) After 20-30 minutes, the temperature of the reaction kettle is raised to 90-98°C, and vacuum is continuously drawn for 2-3 hours to remove acetone to obtain a prepolymer of component B.

5. The modified polyurea coating according to claim 1, characterized in that: After the preparation of the A component prepolymer and the B component prepolymer is completed, they need to be stored separately. When using the coating, the A component prepolymer and the B component prepolymer are respectively charged into the spray gun of a special spraying device, and the special spraying device mixes and sprays the A component prepolymer and the B component prepolymer through the spray gun. The A component prepolymer and the B component prepolymer react and solidify quickly to form an elastomeric waterproof film. The solidification time of the A component prepolymer and the B component prepolymer is 12-22s.