A two-component polyaspartic acid ester polyurea coating, its preparation method and application method

Abstract

This invention discloses a two-component polyaspartic ester polyurea coating, its preparation method, and its application method. In preparing the two-component polyaspartic ester polyurea coating, epoxidized soybean oil and acrylic acid are reacted to obtain a modified soybean oil diluent; polyphenolized lignin and excess toluene diisocyanate are reacted, followed by reactions with excess 2,4-dihydroxybenzophenone and p-allylphenol to obtain a blocked isocyanate curing agent; polyaspartic resin, modified soybean oil diluent, dispersant, thixotropic agent, rheology modifier, defoamer, silane coupling agent, titanium dioxide, precipitated barium sulfate, and talc are mixed evenly as component A; the blocked isocyanate curing agent, butyl acetate, and propylene glycol methyl ether acetate are mixed evenly as component B. When using, components A and B are mixed at a mass ratio of 2:1. The two-component polyaspartic ester polyurea coating prepared by this invention exhibits excellent tensile strength and adhesion.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a two-component polyaspartic ester polyurea coating and its preparation and application methods. Background Technology

[0002] Polyurea elastomers are solvent-free, pollution-free, high-performance, and environmentally friendly materials. They are a new type of material developed in recent years, following environmentally friendly coatings such as high-solids coatings, water-based coatings, UV-cured coatings, and powder coatings. Currently, they are widely used in the field of material protection. Polyaspartic acid ester is an aliphatic secondary amine chain extender. Polyurea prepared from polyaspartic acid ester and aliphatic isocyanate is a novel aliphatic polyurea with excellent physicochemical properties, representing the latest stage in polyurea development. Compared with traditional polyurea, the reaction time of polyaspartic acid ester polyurea is adjustable, and the resulting coating has very few surface defects.

[0003] Vegetable oil, as an environmentally friendly and renewable resource, has long been used in the chemical industry. Today, products using vegetable oil to replace traditional petrochemical raw materials are widely used in various industrial sectors. However, research on the industrial applications of soybean oil is mostly still in the laboratory stage, and in many areas, it is even a blank slate. Therefore, modifying vegetable oil as an active diluent to prepare polyaspartic ester polyurea coatings with good mechanical properties and adhesion has significant market value. Summary of the Invention

[0004] To address the above-mentioned technical problems, this invention provides a two-component polyaspartic ester polyurea coating, its preparation method, and its application method.

[0005] In a first aspect, the present invention provides a two-component polyaspartic ester polyurea coating, which is achieved by the following technical solution.

[0006] A two-component polyaspartic ester polyurea coating, comprising component A and component B,

[0007] Component A comprises the following components in parts by weight: 35-40 parts polyaspartic resin, 10-15 parts modified soybean oil diluent, 0.5-1 part dispersant, 0.3-0.5 parts thixotropic agent, 0.1-0.2 parts rheology modifier, 0.2-0.3 parts defoamer, 0.5-1 part silane coupling agent, 30-35 parts titanium dioxide, 5-10 parts precipitated barium sulfate, and 3-5 parts talc.

[0008] Component B comprises the following components in parts by weight: 70-80 parts of blocked isocyanate curing agent, 3-5 parts of butyl acetate, and 3-5 parts of propylene glycol methyl ether acetate.

[0009] Furthermore, the polyaspartic acid ester resin is selected from one or more of F520, F420, F220, NH1420, NH1520, and NH1220.

[0010] Furthermore, the modified soybean oil diluent is prepared by reacting epoxidized soybean oil and acrylic acid.

[0011] Furthermore, the modified soybean oil diluent is prepared as follows: epoxidized soybean oil and the catalyst triphenylphosphine are mixed evenly at a mass ratio of 1:0.006-0.008. Under stirring conditions of 80-90℃ and 200-300r / min, acrylic acid with an equimolar amount of epoxy groups in the epoxidized soybean oil is added dropwise over 40-50 minutes. After the addition is completed, the temperature is raised to 110-120℃ and the reaction is continued to be stirred for 6-8 hours to obtain the modified soybean oil diluent.

[0012] Furthermore, the blocked isocyanate curing agent is prepared by reacting polyphenolized lignin with excess toluene diisocyanate to obtain a semi-blocked isocyanate curing agent, which is then prepared by reacting the semi-blocked isocyanate curing agent with excess 2,4-dihydroxybenzophenone and p-allylphenol.

[0013] Furthermore, the preparation method of the blocked isocyanate curing agent is as follows: polyphenolized lignin, toluene diisocyanate and acetone are mixed evenly in a mass ratio of 1:4:6-8, and stirred at 50-60°C and 200-300 r / min for 3-4 hours in a nitrogen atmosphere. Then, the mixture is poured into 20-30 times the mass of polyphenolized lignin in diethyl ether, allowed to stand for 20-30 minutes, centrifuged, washed 3-5 times with diethyl ether, and dried at 40-50°C for 6-8 hours in a nitrogen atmosphere to obtain a semi-blocked isocyanate curing agent. A semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol, and acetone were mixed evenly in a mass ratio of 1:0.3-0.4:3-4:6-8. The mixture was stirred at 50-60°C and 200-300 rpm for 3-4 hours under a nitrogen atmosphere. The mixture was then poured into 20-30 times its mass of polyphenolized lignin in diethyl ether, allowed to stand for 20-30 minutes, centrifuged, washed 3-5 times with diethyl ether, and dried at 40-50°C for 6-8 hours under a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0014] Furthermore, the preparation method of the polyphenolized lignin is as follows: lignin and 1-hexyl-3-methylimidazolium bromide are mixed in a mass ratio of 1:2 to 3, and the mixture is placed in a sealed system under a nitrogen atmosphere and stirred at 110 to 120°C and 200 to 300 r / min for 3 to 4 hours. The mixture is then washed with a mixture of water and ethyl acetate in a volume ratio of 1:1 for 8 to 10 minutes. After standing and separating into layers, the oil phase is collected and dried at 50 to 60°C and 50 to 100 Pa for 6 to 8 hours to obtain polyphenolized lignin.

[0015] Furthermore, the toluene diisocyanate is selected from one or more of toluene-2,3-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,4-diisocyanate, and toluene-3,5-diisocyanate.

[0016] Furthermore, the dispersant is selected as BYK163.

[0017] Furthermore, the thixotropic agent is selected as type R972.

[0018] Furthermore, the rheology modifier is selected as EFKA-3777.

[0019] Furthermore, the defoamer is selected from one or more of BYK-077 and BYK-1790.

[0020] Furthermore, the silane coupling agent is selected from one or more of allyltriethoxysilane, allyltrimethoxysilane, vinyltriethoxysilane, and vinyltrimethoxysilane.

[0021] Furthermore, the titanium dioxide is selected as type R902.

[0022] Furthermore, the talc powder is 1250 mesh talc powder.

[0023] Secondly, the present invention provides a method for preparing a two-component polyaspartic ester polyurea coating, which is achieved by the following technical solution.

[0024] A method for preparing the above-mentioned two-component polyaspartic ester polyurea coating includes the following steps:

[0025] The specified amounts of polyaspartic resin, modified soybean oil diluent, dispersant, thixotropic agent, rheology modifier, defoamer, silane coupling agent, titanium dioxide, precipitated barium sulfate, and talc are mixed and dispersed evenly, with a grinding fineness ≤30μm, as component A; the specified amounts of blocked isocyanate curing agent, butyl acetate, and propylene glycol methyl ether acetate are mixed evenly as component B; when using, components A and B are mixed at a mass ratio of 2:1 to obtain a two-component polyaspartic ester polyurea coating.

[0026] Thirdly, the present invention provides a method for using a two-component polyaspartic ester polyurea coating, which is achieved by the following technical solution.

[0027] A method for using the above-mentioned two-component polyaspartic ester polyurea coating is as follows: the two-component polyaspartic ester polyurea coating is uniformly coated on the surface of the substrate, heated to 125-130°C, and irradiated with a 350W or 500W high-pressure mercury lamp at a distance of 2-3cm above the coated surface for 40-50s. The surface is then kept at 125-130°C for 60-80min, and allowed to cool naturally to room temperature and stand for 20-24h.

[0028] This application has the following beneficial effects.

[0029] (1) The solid content of this application is high, the activity of polyaspartic resin and isocyanate curing agent is strong, and their reaction rate will be greatly accelerated. Therefore, a blocked isocyanate curing agent is prepared and cross-linking and curing are carried out by thermal initiation. The lignin is polyphenolized to form a benzene polyphenol structure, which has good antioxidant properties and can block more isocyanates. The subsequent binding of 2,4-dihydroxybenzophenone and p-allylphenol corresponds to more, making the degree of cross-linking higher, thereby improving tensile strength and adhesion. 2,4-dihydroxybenzophenone is used to participate in the end-capping. 2,4-dihydroxybenzophenone can be used as a photoinitiator to initiate the polymerization of free radical unsaturated bonds and form a photoinitiated cross-linking network, which further improves tensile strength and adhesion.

[0030] (2) The epoxy groups on the modified soybean oil diluent open to form hydroxyl groups, and the acrylic acid binds to the modified soybean oil diluent by forming ester groups, so that the modified soybean oil diluent can participate in the curing of isocyanate and photo-initiated free radical polymerization through double bonds and hydroxyl groups, thereby improving tensile strength and adhesion; the use of silane coupling agents with double bonds can participate in the photo-initiated polymerization of unsaturated free radicals, which further improves adhesion. Detailed Implementation

[0031] The present patent application will be further described below with reference to the embodiments.

[0032] Unless otherwise specified, the experimental methods used in the following preparation examples and embodiments are conventional methods; the materials and reagents used in the following preparation examples and embodiments are commercially available unless otherwise specified.

[0033] Example 1

[0034] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0035] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2. The reactor was sealed under a nitrogen atmosphere and stirred at 110°C and 200 r / min for 4 h. The mixture was washed with a mixture of pure water and ethyl acetate at a volume ratio of 1:1 for 8 min. After standing and separating the layers, the oil phase was collected and dried at 50°C and 50 Pa for 8 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:6 and stirred at 50°C and 200 r / min for 4 h under a nitrogen atmosphere. Then, polyphenolized lignin was added. A semi-closed isocyanate curing agent was prepared by standing in 20 times its weight of diethyl ether for 30 minutes, centrifuging, washing three times with diethyl ether, and drying at 40°C for 8 hours under a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.3:3:6 and stirred at 50°C and 200 r / min for 4 hours under a nitrogen atmosphere. The mixture was then poured into 20 times its weight of diethyl ether for 20 minutes, centrifuged, washed three times with diethyl ether, and dried at 40°C for 8 hours under a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0036] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.008. Under the stirring conditions of 80℃ and 200r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 40min. After the addition was completed, the temperature was raised to 110℃ and the reaction was stirred for 8h to obtain modified soybean oil diluent.

[0037] (3) Weigh out the following components by mass: 105g of F520 polyaspartic resin, 30g of modified soybean oil diluent, 1.5g of BYK163 dispersant, 0.9g of R972 thixotropic agent, 0.3g of EFKA-3777 rheology modifier, 0.6g of BYK-077 defoamer, 1.5g of allyltriethoxysilane, 90g of R902 titanium dioxide, 15g of precipitated barium sulfate, and 9g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 70g of blocked isocyanate curing agent, 3g of butyl acetate, and 3g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain a two-component polyaspartic ester polyurea coating.

[0038] Example 2

[0039] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0040] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2.5. The reactor was sealed under a nitrogen atmosphere and stirred at 115°C and 250 r / min for 3.5 h. The mixture was washed with a 1:1 volume ratio of pure water and ethyl acetate for 9 min. After standing and separating the layers, the oil phase was collected and dried at 55°C and 70 Pa for 7 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:7 and stirred at 55°C and 250 r / min for 3.5 h under a nitrogen atmosphere. Then the mixture was added to the high-pressure reactor. A semi-closed isocyanate curing agent was prepared by standing in 25 times the mass of polyphenolized lignin in diethyl ether for 25 min, centrifuging, washing with diethyl ether 4 times, and drying at 45°C for 7 h in a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.35:3.5:7 and stirred at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. The mixture was then poured into 25 times the mass of polyphenolized lignin in diethyl ether, stood for 25 min, centrifuged, washed with diethyl ether 4 times, and dried at 45°C for 7 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0041] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.007. Under the stirring conditions of 85℃ and 250r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 45min. After the addition was completed, the temperature was raised to 115℃ and the reaction was continued for 7h to obtain modified soybean oil diluent.

[0042] (3) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of modified soybean oil diluent, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 2.4g of allyltriethoxysilane, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0043] Example 3

[0044] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0045] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:3. The reactor was sealed under a nitrogen atmosphere and stirred at 120°C and 300 r / min for 3 h. The mixture was washed with a mixture of pure water and ethyl acetate at a volume ratio of 1:1 for 10 min. After standing and separating into layers, the oil phase was collected and dried at 60°C and 100 Pa for 6 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:8 and stirred at 60°C and 300 r / min for 3 h under a nitrogen atmosphere. Then, the polyphenolized lignin was added to the mixture. A semi-closed isocyanate curing agent was prepared by standing in 30 times the mass of polyphenolized lignin in diethyl ether for 30 min, centrifuging, washing with diethyl ether 5 times, and drying at 50°C for 6 h in a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.4:4:8 and stirred at 300 r / min for 3 h in a nitrogen atmosphere. The mixture was then poured into 30 times the mass of polyphenolized lignin in diethyl ether, stood for 30 min, centrifuged, washed with diethyl ether 5 times, and dried at 50°C for 6 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0046] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.008. Under the stirring conditions of 90℃ and 300r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 50min. After the addition was completed, the temperature was raised to 120℃ and the reaction was continued for 6h to obtain modified soybean oil diluent.

[0047] (3) Weigh out the following components by mass: 120g of F520 polyaspartic resin, 45g of modified soybean oil diluent, 3g of BYK163 dispersant, 1.5g of R972 thixotropic agent, 0.6g of EFKA-3777 rheology modifier, 0.9g of BYK-077 defoamer, 3g of allyltriethoxysilane, 105g of R902 titanium dioxide, 30g of precipitated barium sulfate, and 15g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 80g of blocked isocyanate curing agent, 5g of butyl acetate, and 5g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain a two-component polyaspartic ester polyurea coating.

[0048] Comparative Example 1

[0049] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0050] (1) Mix lignin, toluene-2,4-diisocyanate and acetone in a mass ratio of 1:4:7. Stir and react at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. Then pour into 25 times the mass of lignin in diethyl ether, let stand for 25 min, centrifuge, wash with diethyl ether 4 times, and dry at 45°C for 7 h in a nitrogen atmosphere to obtain a semi-closed isocyanate curing agent. Mix the semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone in a mass ratio of 1:0.35:3.5:7. Stir and react at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. Then pour into 25 times the mass of lignin in diethyl ether, let stand for 25 min, centrifuge, wash with diethyl ether 4 times, and dry at 45°C for 7 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0051] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.007. Under the stirring conditions of 85℃ and 250r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 45min. After the addition was completed, the temperature was raised to 115℃ and the reaction was continued for 7h to obtain modified soybean oil diluent.

[0052] (3) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of modified soybean oil diluent, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 2.4g of allyltriethoxysilane, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0053] Comparative Example 2

[0054] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0055] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2.5. The reactor was sealed under a nitrogen atmosphere and stirred at 115°C and 250 r / min for 3.5 h. The mixture was washed with a mixture of pure water and ethyl acetate at a volume ratio of 1:1 for 9 min. After standing and separating the layers, the oil phase was collected and dried at 55°C and 70 Pa for 7 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:7 and stirred at 55°C and 250 r / min for 3.5 h under a nitrogen atmosphere. Then, pour the mixture into 25 times the mass of polyphenolized lignin in diethyl ether, let it stand for 25 minutes, centrifuge, wash it 4 times with diethyl ether, and dry it at 45°C for 7 hours in a nitrogen atmosphere to obtain a semi-closed isocyanate curing agent. Mix the semi-closed isocyanate curing agent, p-allylphenol, and acetone at a mass ratio of 1:3.5:7 evenly, stir and react at 55°C and 250 r / min for 3.5 hours in a nitrogen atmosphere, then pour the mixture into 25 times the mass of polyphenolized lignin in diethyl ether, let it stand for 25 minutes, centrifuge, wash it 4 times with diethyl ether, and dry it at 45°C for 7 hours in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0056] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.007. Under the stirring conditions of 85℃ and 250r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 45min. After the addition was completed, the temperature was raised to 115℃ and the reaction was continued for 7h to obtain modified soybean oil diluent.

[0057] (3) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of modified soybean oil diluent, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 2.4g of allyltriethoxysilane, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0058] Comparative Example 3

[0059] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0060] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2.5. The reactor was sealed under a nitrogen atmosphere and stirred at 115°C and 250 r / min for 3.5 h. The mixture was washed with a 1:1 volume ratio of pure water and ethyl acetate for 9 min. After standing and separating the layers, the oil phase was collected and dried at 55°C and 70 Pa for 7 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:7 and stirred at 55°C and 250 r / min for 3.5 h under a nitrogen atmosphere. Then the mixture was added to the high-pressure reactor. A semi-closed isocyanate curing agent was prepared by standing in 25 times the mass of polyphenolized lignin in diethyl ether for 25 min, centrifuging, washing with diethyl ether 4 times, and drying at 45°C for 7 h in a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.35:3.5:7 and stirred at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. The mixture was then poured into 25 times the mass of polyphenolized lignin in diethyl ether, stood for 25 min, centrifuged, washed with diethyl ether 4 times, and dried at 45°C for 7 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0061] (2) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of soybean oil, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 2.4g of allyltriethoxysilane, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0062] Comparative Example 4

[0063] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0064] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2.5. The reactor was sealed under a nitrogen atmosphere and stirred at 115°C and 250 r / min for 3.5 h. The mixture was washed with a 1:1 volume ratio of pure water and ethyl acetate for 9 min. After standing and separating the layers, the oil phase was collected and dried at 55°C and 70 Pa for 7 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:7 and stirred at 55°C and 250 r / min for 3.5 h under a nitrogen atmosphere. Then the mixture was added to the high-pressure reactor. A semi-closed isocyanate curing agent was prepared by standing in 25 times the mass of polyphenolized lignin in diethyl ether for 25 min, centrifuging, washing with diethyl ether 4 times, and drying at 45°C for 7 h in a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.35:3.5:7 and stirred at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. The mixture was then poured into 25 times the mass of polyphenolized lignin in diethyl ether, stood for 25 min, centrifuged, washed with diethyl ether 4 times, and dried at 45°C for 7 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0065] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.007. Under the stirring conditions of 85℃ and 250r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 45min. After the addition was completed, the temperature was raised to 115℃ and the reaction was continued for 7h to obtain modified soybean oil diluent.

[0066] (3) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of modified soybean oil diluent, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 2.4g of propyltriethoxysilane, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0067] Comparative Example 5

[0068] A method for preparing a two-component polyaspartic acid ester polyurea coating mainly includes the following preparation steps:

[0069] (1) Lignin and 1-hexyl-3-methylimidazolium bromide were placed in a high-pressure reactor at a mass ratio of 1:2.5. The reactor was sealed under a nitrogen atmosphere and stirred at 115°C and 250 r / min for 3.5 h. The mixture was washed with a 1:1 volume ratio of pure water and ethyl acetate for 9 min. After standing and separating the layers, the oil phase was collected and dried at 55°C and 70 Pa for 7 h to obtain polyphenolized lignin. Polyphenolized lignin, toluene-2,4-diisocyanate and acetone were mixed evenly at a mass ratio of 1:4:7 and stirred at 55°C and 250 r / min for 3.5 h under a nitrogen atmosphere. Then the mixture was added to the high-pressure reactor. A semi-closed isocyanate curing agent was prepared by standing in 25 times the mass of polyphenolized lignin in diethyl ether for 25 min, centrifuging, washing with diethyl ether 4 times, and drying at 45°C for 7 h in a nitrogen atmosphere. The semi-closed isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol and acetone were mixed evenly in a mass ratio of 1:0.35:3.5:7 and stirred at 55°C and 250 r / min for 3.5 h in a nitrogen atmosphere. The mixture was then poured into 25 times the mass of polyphenolized lignin in diethyl ether, stood for 25 min, centrifuged, washed with diethyl ether 4 times, and dried at 45°C for 7 h in a nitrogen atmosphere to obtain a closed isocyanate curing agent.

[0070] (2) Epoxidized soybean oil and triphenylphosphine were mixed evenly at a mass ratio of 1:0.007. Under the stirring conditions of 85℃ and 250r / min, acrylic acid of equimolar amount of epoxy group in epoxidized soybean oil was added dropwise over 45min. After the addition was completed, the temperature was raised to 115℃ and the reaction was continued for 7h to obtain modified soybean oil diluent.

[0071] (3) Weigh out the following components by mass: 114g of F520 polyaspartic resin, 36g of modified soybean oil diluent, 2.4g of BYK163 dispersant, 1.2g of R972 thixotropic agent, 0.45g of EFKA-3777 rheology modifier, 0.75g of BYK-077 defoamer, 96g of R902 titanium dioxide, 24g of precipitated barium sulfate, and 12g of 1250-mesh talc powder. Mix and disperse the components evenly, and grind them to a fineness ≤30um as component A. Weigh out the following components by mass: 75g of blocked isocyanate curing agent, 4g of butyl acetate, and 4g of propylene glycol methyl ether acetate. Mix and disperse the components evenly as component B. When using, mix component A and component B at a mass ratio of 2:1 to obtain the two-component polyaspartic ester polyurea coating.

[0072] Performance testing

[0073] 1. Tensile strength test

[0074] Test method: The two-component polyaspartic acid ester polyurea coatings obtained in each example and comparative example were placed in a polytetrafluoroethylene mold, heated to 130°C, and irradiated with a 500W high-pressure mercury lamp at a distance of 2cm above the coating surface for 50s. The coating was then kept at 130°C for 60min, allowed to cool naturally to room temperature, and left to stand for 24h. The coatings were then removed, and tensile specimens were prepared according to GB / T258 standard and the tensile strength was tested.

[0075] 2. Adhesion test

[0076] Test method: The two-component polyaspartic acid ester polyurea coatings obtained in each example and comparative example were uniformly coated on a 1 mm thick iron sheet that had been cross-polished and cleaned with acetone. The temperature was raised to 130°C, and a 500W high-pressure mercury lamp was used to irradiate the coated surface from 2 cm above it for 50 seconds. The temperature was then maintained at 130°C for 60 minutes, and the coating was allowed to cool naturally to room temperature and stand for 24 hours. The adhesion was then determined according to GB / T5210.

[0077] The experimental results are shown in Table 1.

[0078] Table 1

[0079] tensile strength Adhesion Example 1 36.2MPa 9.8MPa Example 2 36.5MPa 10.2MPa Example 3 36.8MPa 10.4MPa Comparative Example 1 30.3MPa 8.4MPa Comparative Example 2 25.1MPa 6MPa Comparative Example 3 28.6MPa 8.6MPa Comparative Example 4 36.3MPa 5.8MPa Comparative Example 5 36.5MPa 4.2MPa

[0080] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 1 reveals that the two-component polyaspartic acid ester polyurea coating prepared by the present invention exhibits good tensile strength and adhesion.

[0081] By comparing Examples 1-3 and Comparative Example 1, it can be found that polyphenolization of lignin can block more isocyanates, resulting in more subsequent binding of 2,4-dihydroxybenzophenone and p-allylphenol, leading to a higher degree of crosslinking and thus improving tensile strength and adhesion.

[0082] By comparing Examples 1-3 and Comparative Example 2, it can be found that by using 2,4-dihydroxybenzophenone for end-capping, 2,4-dihydroxybenzophenone can act as a photoinitiator to initiate the polymerization of free radical unsaturated bonds, forming a photoinitiated crosslinking network, which further improves tensile strength and adhesion.

[0083] By comparing Examples 1-3 and Comparative Example 3, it can be found that, compared with the direct use of soybean oil, the modified soybean oil diluent has the effect of ring-opening of the epoxy groups to form hydroxyl groups, and the acrylic acid binds to the modified soybean oil diluent by forming ester groups. This allows the modified soybean oil diluent to participate in the curing of isocyanate and photo-initiated free radical polymerization through double bonds and hydroxyl groups, thereby improving tensile strength and adhesion.

[0084] By comparing Examples 1-3 and Comparative Examples 4-5, it can be found that the use of silane coupling agents can improve adhesion. The use of silane coupling agents with double bonds can participate in the photo-initiated polymerization of unsaturated free radicals, which further improves adhesion.

[0085] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A two-component polyaspartic ester polyurea coating, characterized in that: Includes component A and component B. Component A comprises the following components in parts by weight: 35-40 parts polyaspartic resin, 10-15 parts modified soybean oil diluent, 0.5-1 part dispersant, 0.3-0.5 parts thixotropic agent, 0.1-0.2 parts rheology modifier, 0.2-0.3 parts defoamer, 0.5-1 part silane coupling agent, 30-35 parts titanium dioxide, 5-10 parts precipitated barium sulfate, and 3-5 parts talc. Component B comprises the following components in parts by weight: 70-80 parts of blocked isocyanate curing agent, 3-5 parts of butyl acetate, and 3-5 parts of propylene glycol methyl ether acetate; The modified soybean oil diluent is prepared by reacting epoxidized soybean oil and acrylic acid; The blocked isocyanate curing agent is prepared by reacting polyphenolized lignin with excess toluene diisocyanate to obtain a semi-blocked isocyanate curing agent, which is then prepared by reacting the semi-blocked isocyanate curing agent with excess 2,4-dihydroxybenzophenone and p-allylphenol.

2. The two-component polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The polyaspartic acid ester resin is selected from one or more of F520, F420, F220, NH1420, NH1520, and NH1220.

3. The two-component polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The modified soybean oil diluent is prepared as follows: Epoxidized soybean oil and triphenylphosphine catalyst are mixed evenly at a mass ratio of 1:0.006~0.

008. Under stirring conditions of 80~90℃ and 200~300r / min, acrylic acid with an equimolar amount of epoxy groups in the epoxidized soybean oil is added dropwise over 40~50min. After the addition is completed, the temperature is raised to 110~120℃ and the reaction is continued to be stirred for 6~8h to obtain the modified soybean oil diluent.

4. The two-component polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The preparation method of the blocked isocyanate curing agent is as follows: Polyphenolized lignin, toluene diisocyanate and acetone are mixed evenly in a mass ratio of 1:4:6~8. The mixture is stirred at 50~60℃ and 200~300 r / min for 3~4 h under a nitrogen atmosphere. Then, it is poured into 20~30 times the mass of the polyphenolized lignin in diethyl ether, allowed to stand for 20~30 min, centrifuged, washed 3~5 times with diethyl ether, and dried at 40~50℃ for 6~8 h under a nitrogen atmosphere to obtain a semi-blocked isocyanate curing agent. A blocked isocyanate curing agent, 2,4-dihydroxybenzophenone, p-allylphenol, and acetone are mixed evenly in a mass ratio of 1:0.3~0.4:3~4:6~8. The mixture is stirred at 50~60℃ and 200~300r / min for 3~4h under a nitrogen atmosphere. The mixture is then poured into 20~30 times the mass of polyphenolized lignin in diethyl ether, allowed to stand for 20~30min, centrifuged, washed 3~5 times with diethyl ether, and dried at 40~50℃ for 6~8h under a nitrogen atmosphere to obtain the blocked isocyanate curing agent.

5. The two-component polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The preparation method of the polyphenolized lignin is as follows: lignin and 1-hexane-3-methylimidazolium bromide are mixed in a mass ratio of 1:2~3, and the mixture is placed in a closed system under a nitrogen atmosphere and stirred at 110~120℃ and 200~300r / min for 3~4h. The mixture is then washed with a mixture of water and ethyl acetate in a volume ratio of 1:1 for 8~10min. After standing and separating into layers, the oil phase is collected and dried at 50~60℃ and 50~100Pa for 6~8h to obtain polyphenolized lignin.

6. The two-component polyaspartic acid ester polyurea coating according to claim 1, characterized in that: The toluene diisocyanate is selected from one or a mixture of toluene-2,3-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,4-diisocyanate, and toluene-3,5-diisocyanate.

7. A method for preparing a two-component polyaspartic acid ester polyurea coating according to any one of claims 1-6, characterized in that: Includes the following steps: The specified amounts of polyaspartic resin, modified soybean oil diluent, dispersant, thixotropic agent, rheology modifier, defoamer, silane coupling agent, titanium dioxide, precipitated barium sulfate, and talc are mixed and dispersed evenly, with a grinding fineness ≤30μm, as component A; the specified amounts of blocked isocyanate curing agent, butyl acetate, and propylene glycol methyl ether acetate are mixed evenly as component B; when using, components A and B are mixed at a mass ratio of 2:1 to obtain a two-component polyaspartic ester polyurea coating.

8. A method of using the two-component polyaspartic ester polyurea coating according to any one of claims 1-6, characterized in that: The two-component polyaspartic acid ester polyurea coating is uniformly applied to the substrate surface, heated to 125~130℃, and irradiated with a 350W or 500W high-pressure mercury lamp at a distance of 2~3cm above the coating surface for 40~50s. The temperature is then maintained at 125~130℃ for 60~80min, and the coating is allowed to cool naturally to room temperature and stand for 20~24h.