Bio-based weather-resistant finish paint with good adhesion and preparation method of bio-based weather-resistant finish paint

Abstract

The invention discloses a bio-based weather-resistant finish paint with good adhesion and a preparation method thereof, the finish paint comprises a component A and a component B. The component A comprises polyol resin, an adhesion promoter, a dispersant, a defoaming agent, a leveling agent, an anti-ultraviolet agent, a coalescing agent and a solvent; the component B comprises a bio-based curing agent and deionized water; the weight of the component B is 10-22% of the weight of the component A; wherein the preparation of the adhesion promoter comprises the following steps: dispersing 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, methacryloxy ester and an initiator in a solvent in a nitrogen atmosphere, and carrying out primary heating reaction in a stirring state; after the reaction is finished, adding boric acid, and carrying out secondary heating reaction in a stirring state; and after the reaction is finished, removing the solvent by reduced pressure distillation. The finish paint has excellent adhesive force, and is not easy to blister, partially peel off or integrally peel off after being used for a long time.

Description

Technical Field

[0001] The invention relates to a bio-based weather-resistant topcoat with good adhesion and a preparation method thereof, belonging to the technical field of coatings. Background Art

[0002] Polyol resin topcoats usually have good weather resistance, abrasion resistance and chemical resistance, and are widely used in various coating fields. They use polyol resin as the main film-forming substance. Polyol resin topcoats can resist the damage of ultraviolet rays for a long time, are not prone to yellowing and fading, and have high hardness, can resist wear and scratches, maintain the integrity and aesthetics of the coating, and have good construction performance. They can be easily applied by spraying, roller coating, etc. Although polyol resin topcoats can adhere to the substrate to a certain extent, they are still prone to blistering, partial peeling or overall peeling after long-term use. Summary of the invention

[0003] The object of the present invention is to provide a bio-based weather-resistant topcoat with good adhesion and a preparation method thereof. The topcoat has excellent adhesion and is not prone to blistering, partial peeling or overall peeling after long-term use.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A bio-based weather-resistant topcoat with good adhesion, comprising component A and component B, wherein component A comprises the following components by mass percentage: 65-80% of polyol resin, 3-7% of adhesion promoter, 0.2-1% of dispersant, 0.5-3% of defoamer, 0.5-3% of leveling agent, 0.5-2% of anti-ultraviolet agent, 2-5% of film-forming aid, and 10-20% of solvent;

[0006] Component B includes the following components by mass percentage: 50-60% bio-based curing agent, 40-50% deionized water;

[0007] Among them, the preparation method of the adhesion promoter is: under a nitrogen atmosphere, 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, methacrylate and initiator are dispersed in a solvent, and heated for a first reaction under stirring; after the reaction is completed, boric acid is added, and heated for a second reaction under stirring; after the reaction is completed, the solvent is removed by reduced pressure distillation.

[0008] The weight of component B is 10-22% of the weight of component A.

[0009] Preferably, the polyol resin is at least one of polyester polyol and polyether polyol.

[0010] Preferably, the methacrylate oxyester is at least one of 2-ethoxyethyl methacrylate and methoxyethyl methacrylate.

[0011] Preferably, the mass ratio of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, methacrylate, initiator and boric acid is (30-80):(20-50):(0.2-1):(3-10).

[0012] Preferably, the initiator is AIBN and the solvent is dimethyl sulfoxide.

[0013] Preferably, the conditions for the first heating reaction are: 65-85°C, 4-6h; the conditions for the second heating reaction are: 60-70°C, 2-4h.

[0014] Preferably, the preparation method of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid is as follows: under nitrogen protection, 1-hydroxypropyl imidazole and allyl chloride are mixed, heated to reflux at 50-70°C for 5-9h, extracted with ether, and then rotary evaporated at 25-35°C for 0.5-2h, then water and potassium hexafluorophosphate are added, and rotary evaporated at 75-85°C for 2-4h. After the solution is separated, the water layer is removed, the organic phase is washed, and then rotary evaporated at 75-90°C for 3-6h.

[0015] Preferably, the mass ratio of 1-hydroxypropyl imidazole, allyl chloride, water and potassium hexafluorophosphate is 1:(1.1-1.5):(50-80):(1-5).

[0016] Preferably, the organic phase is washed with water and diethyl ether.

[0017] The method for preparing any of the above-mentioned bio-based weather-resistant topcoats with good adhesion comprises the following steps:

[0018] Preparation of component A: Mix and stir the polyol resin, adhesion promoter, dispersant, solvent and part of the defoamer, then add the anti-ultraviolet agent, film-forming aid and the remaining defoamer, stir to obtain a blended liquid of component A;

[0019] Preparation of component B: blending the bio-based curing agent and deionized water to obtain a blended liquid of component B;

[0020] Preparation of topcoat: Mix the blending liquid of component A and component B according to the proportion to obtain a topcoat.

[0021] The beneficial effects of the present invention are:

[0022] Dynamic cross-linking is carried out between the copolymer of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid and methacrylate and boric acid. The obtained boric acid ester can expose the terminal hydroxyl group of the ionic liquid side chain after dissociation in water, and then non-covalent interaction occurs between the substrate and the adhesion is improved. DETAILED DESCRIPTION

[0023] The bio-based weather-resistant topcoat prepared by the present invention comprises component A and component B, wherein component A comprises the following components by mass percentage: 65-80% of polyol resin (polyester polyol or polyether polyol), 3-7% of adhesion promoter, 0.2-1% of dispersant, 0.5-3% of defoamer, 0.5-3% of leveling agent, 0.5-2% of anti-ultraviolet agent, 2-5% of film-forming aid, and 10-20% of solvent. Component B comprises the following components by mass percentage: 50-60% of bio-based curing agent and 40-50% of deionized water. The weight of component B is 10-22% of the weight of component A.

[0024] Among them, the preparation method of the adhesion promoter is: disperse 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, 30g 2-ethoxyethyl methacrylate or 27g methoxyethyl methacrylate and 0.5g AIBN in 200ml dimethyl sulfoxide, heat to 70°C and react for 5h under stirring; after the reaction is completed, cool to room temperature, add 5g boric acid, heat to 65°C and react for 3h under stirring; after the reaction is completed, remove the solvent by reduced pressure distillation.

[0025] The preparation method of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid is as follows: under nitrogen protection, 1 part of 1-hydroxypropyl imidazole and 1.3 parts of allyl chloride are mixed by mass, heated to reflux at 60°C for 7 hours, extracted twice with ether, and then rotary evaporated at 30°C for 1 hour, then 70 parts of water and 2.5 parts of potassium hexafluorophosphate are added, and rotary evaporated at 80°C for 3 hours. After the solution is separated, the water layer is removed, the organic phase is washed once with water and ether, and then rotary evaporated at 80°C for 5 hours.

[0026] In the following examples, some of the components used in the topcoat are as follows:

[0027] Dispersant: 4240;

[0028] Leveling agent: RM-2020;

[0029] Solvent: alcohol solvent;

[0030] Defoaming agent: 334;

[0031] Film-forming aid: C-12;

[0032] Bio-based curing agent: Stabio D-3725N.

[0033] Example 1

[0034] The components and contents of topcoat component A are as follows:

[0035] Polyester polyols 70％ Leveling agent 2％ Adhesion promoter 5％ Film-forming aids 3％ Dispersants 0.5％ Solvents 18％ Defoaming agent 1.5％ total 100％

[0036] The components and contents of component B are as follows:

[0037] Bio-based curing agent 60％ Deionized water 40％

[0038] The method for preparing the above-mentioned bio-based weather-resistant topcoat comprises the following steps:

[0039] Preparation of component A: Add polyol resin, adhesion promoter, dispersant, solvent and half of defoamer into a reaction kettle, stir at 500 rpm, then add anti-ultraviolet agent, film-forming aid and remaining defoamer, continue stirring to obtain component A blending liquid;

[0040] Preparation of component B: adding the bio-based curing agent and deionized water into a reaction kettle and blending at a speed of 500 rpm to obtain a blended liquid of component B;

[0041] Preparation of topcoat: The blended liquid of component A and component B were mixed at a ratio of 8:1 (800 rpm) to obtain a topcoat.

[0042] Example 2

[0043] The components and contents of topcoat component A are as follows:

[0044] Polyether polyols 70％ Leveling agent 2％ Adhesion promoter 5％ Film-forming aids 3％ Dispersants 0.5％ Solvents 18％ Defoaming agent 1.5％ total 100％

[0045] The components and contents of component B are as follows:

[0046] Bio-based curing agent 60％ Deionized water 40％

[0047] The method for preparing the above-mentioned bio-based weather-resistant topcoat comprises the following steps:

[0048] Preparation of component A: Add polyol resin, adhesion promoter, dispersant, solvent and half of defoamer into a reaction kettle, stir at 500 rpm, then add anti-ultraviolet agent, film-forming aid and remaining defoamer, continue stirring to obtain component A blending liquid;

[0049] Preparation of component B: adding the bio-based curing agent and deionized water into a reaction kettle and blending at a speed of 500 rpm to obtain a blended liquid of component B;

[0050] Preparation of topcoat: The blended liquid of component A and component B were mixed at a ratio of 8:1 (800 rpm) to obtain a topcoat.

[0051] Comparative Example 1

[0052] The components and contents of topcoat component A are as follows:

[0053] Polyester polyols 75％ Film-forming aids 3％ Dispersants 0.5％ Solvents 18％ Defoaming agent 1.5％ total 100％ Leveling agent 2％

[0054] The components and contents of component B are as follows:

[0055] Bio-based curing agent 60％ Deionized water 40％

[0056] The method for preparing the above-mentioned bio-based weather-resistant topcoat comprises the following steps:

[0057] Preparation of component A: Add polyol resin, dispersant, solvent and half of defoamer into a reaction kettle, stir at 500 rpm, then add anti-ultraviolet agent, film-forming aid and remaining defoamer, continue stirring to obtain component A blending liquid;

[0058] Preparation of component B: adding the bio-based curing agent and deionized water into a reaction kettle and blending at a speed of 500 rpm to obtain a blended liquid of component B;

[0059] Preparation of topcoat: The blended liquid of component A and component B were mixed at a ratio of 8:1 (800 rpm) to obtain a topcoat.

[0060] Comparative Example 2

[0061] The components and contents of topcoat component A are as follows:

[0062] Polyether polyols 70％ Film-forming aids 3％ Dispersants 0.5％ Solvents 18％ Defoaming agent 1.5％ total 100％ Leveling agent 2％

[0063] The components and contents of component B are as follows:

[0064] Bio-based curing agent 60％ Deionized water 40％

[0065] The method for preparing the above-mentioned bio-based weather-resistant topcoat comprises the following steps:

[0066] Preparation of component A: Add polyol resin, dispersant, solvent and half of defoamer into a reaction kettle, stir at 500 rpm, then add anti-ultraviolet agent, film-forming aid and remaining defoamer, continue stirring to obtain component A blending liquid;

[0067] Preparation of component B: adding the bio-based curing agent and deionized water into a reaction kettle and blending at a speed of 500 rpm to obtain a blended liquid of component B;

[0068] Preparation of topcoat: The blended liquid of component A and component B were mixed at a ratio of 8:1 (800 rpm) to obtain a topcoat.

[0069] The adhesion test of the topcoat prepared in Example 1-2 and Comparative Example 1-2 was performed, and the specific process was as follows:

[0070] The hot-dip galvanized steel sheet was immersed in a 5% sodium hydroxide solution for 8 hours, then rinsed with clean water, dried and shot peened; a primer was sprayed on the surface of the hot-dip galvanized steel sheet, and a 0.3-0.5 mm thick primer layer was formed after drying; and the topcoat prepared in the above embodiment and comparative example was sprayed on the surface of the primer layer, and a 0.5-0.6 mm thick topcoat layer was formed after drying.

[0071] The hot-dip galvanized steel sheets with the topcoat layer were immersed in hot water at 85°C for different lengths of time to test the adhesion level of the topcoat layer. The specific results are shown in Table 1; Level 1 and Level 2 are firm adhesion without separation and a smooth surface, Level 3 is firm adhesion but bubbles are generated on the surface, Level 4 is partial peeling, and Level 5 is peeling of the topcoat layer.

[0072] Table 1 Test results of the adhesion of the topcoat layer on hot-dip galvanized steel plates sprayed with different topcoats

[0073] Example 1 Example 2 Comparative Example 1 Comparative Example 2 0h 1 1 1 1 24h 1 1 1 1 48h 1 1 1 1 8d 1 1 2 2 20d 1 1 3 3 30d 2 2 4 4

[0074] As can be seen from Table 1, after the adhesion promoter is used in Example 1-2, the obtained topcoat layer has excellent adhesion effect. The reason is that the 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid is copolymerized with methacrylate and then dynamically cross-linked with boric acid. The obtained boric acid ester can expose the terminal hydroxyl group of the ionic liquid side chain after dissociation in water, and then non-covalent interaction occurs with the substrate, thereby improving adhesion and enhancing the adhesion effect.

[0075] The above is only a preferred implementation of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.

Claims

1. A bio-based weather-resistant topcoat with good adhesion, characterized in that: It includes component A and component B, wherein component A includes the following components by mass percentage: 65-80% polyol resin, 3-7% adhesion promoter, 0.2-1% dispersant, 0.5-3% defoamer, 0.5-3% leveling agent, 0.5-2% anti-ultraviolet agent, 2-5% film-forming aid, and 10-20% solvent; Component B includes the following components by mass percentage: 50-60% bio-based curing agent, 40-50% deionized water; The preparation method of the adhesion promoter is as follows: in a nitrogen atmosphere, 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, methacrylate and initiator are dispersed in a solvent, and heated for a first reaction under a stirring state; after the reaction is completed, boric acid is added, and heated for a second reaction under a stirring state; after the reaction is completed, the solvent is removed by reduced pressure distillation; The weight of component B is 10-22% of the weight of component A.

2. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The polyol resin is at least one of polyester polyol and polyether polyol.

3. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The oxymethacrylate is at least one of 2-ethoxyethyl methacrylate and methoxyethyl methacrylate.

4. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The mass ratio of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid, methacrylate, initiator and boric acid is (30-80):(20-50):(0.2-1):(3-10).

5. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The initiator was AIBN and the solvent was dimethyl sulfoxide.

6. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The conditions for the first heating reaction are: 65-85°C, 4-6h; the conditions for the second heating reaction are: 60-70°C, 2-4h.

7. The bio-based weather-resistant topcoat with good adhesion according to claim 1, characterized in that: The preparation method of 1-allyl-3-hydroxypropyl imidazole hexafluorophosphate ionic liquid is as follows: under nitrogen protection, 1-hydroxypropyl imidazole and allyl chloride are mixed, heated to reflux at 50-70°C for 5-9h, extracted with ether, and then rotary evaporated at 25-35°C for 0.5-2h, then water and potassium hexafluorophosphate are added, and rotary evaporated at 75-85°C for 2-4h, the water layer is removed after the solution is separated, the organic phase is washed, and then rotary evaporated at 75-90°C for 3-6h.

8. The bio-based weather-resistant topcoat with good adhesion according to claim 7, characterized in that: The mass ratio of 1-hydroxypropyl imidazole, allyl chloride, water and potassium hexafluorophosphate is 1:(1.1-1.5):(50-80):(1-5).

9. The bio-based weather-resistant topcoat with good adhesion according to claim 7, characterized in that: The organic phase was washed with water and diethyl ether.

10. The method for preparing the bio-based weather-resistant topcoat with good adhesion according to any one of claims 1 to 9, characterized in that: The steps include: Preparation of component A: Mix and stir the polyol resin, adhesion promoter, dispersant, solvent and part of the defoamer, then add the anti-ultraviolet agent, film-forming aid and the remaining defoamer, stir to obtain a blended liquid of component A; Preparation of component B: blending the bio-based curing agent and deionized water to obtain a blended liquid of component B; Preparation of topcoat: Mix the blending liquid of component A and component B according to the proportion to obtain a topcoat.