A solvent-free polyurethane coating and its preparation method

Abstract

This invention relates to a solvent-free polyurethane coating, comprising component A and component B. Component A comprises the following raw materials by mass parts: polyaspartic acid ester resin, 30-50 parts; hydroxyl acrylic resin, 5-15 parts; non-reactive diluent, 5-30 parts; anti-settling agent, 0.5-3 parts; dispersant, 1-5 parts; defoamer, 0.1-1 parts; titanium dioxide, 10-30 parts; barium sulfate, 5-40 parts; leveling agent, 0.1-1 parts; coupling agent, 1-5 parts. Component B comprises the following raw material by mass parts: curing agent, 100 parts. The coating preparation method includes the following steps: step S1, preparation of component A; step S2, preparation of component B. The advantage of this invention is that the coating does not require the use of solvents, avoiding VOC emissions caused by solvent evaporation during film formation and preparation, and preventing the coating's solid content from being affected by evaporation, thus ensuring that the formed coating has good film quality.

Description

Technical Field

[0001] This invention relates to the field of industrial anti-corrosion coatings, and in particular to a solvent-free polyurethane coating and its preparation method. Background Technology

[0002] Polyurethane coatings are based on polyurethane resins and are applied to objects to be protected to form a protective coating. They are widely used in the automotive, shipbuilding, and civil engineering industries.

[0003] However, traditional polyurethane coatings contain a large amount of organic solvents. During the preparation and formulation process, because the organic solvents have low vaporization temperatures, they can easily evaporate into the external environment quickly, causing pollution. Furthermore, the reduction in solvents also affects the volume solids content of the coating, thus reducing the film quality.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a solvent-free polyurethane coating and its preparation method.

[0006] A solvent-free polyurethane coating comprising component A and component B; Component A comprises raw materials in parts by mass: Polyaspartic acid ester resin, 30-50 parts; Hydroxy acrylic resin, 5-15 parts; Non-reactive diluent, 5-30 parts; Anti-settling agent, 0.5-3 parts; Dispersant, 1-5 parts; Defoamer, 0.1 to 1 part; Titanium dioxide, 10-30 parts; Barium sulfate, 5-40 parts; Leveling agent, 0.1~1 part; Coupling agent, 1-5 parts; Component B comprises raw materials in parts by mass: Hardener, 100 parts.

[0007] Furthermore, the mass ratio of component A to component B ranges from 3 to 8:1.

[0008] Furthermore, the polyaspartic acid ester resin has a secondary amine group -NH- equivalent of 290 eq and a viscosity of 900~2000 (mpa.s / 25℃).

[0009] Furthermore, the hydroxyl acrylic resin has a hydroxyl content of 82.5 eq and a solid content of 90%.

[0010] Furthermore, the anti-settling agent is organic bentonite, and the inactive diluent is a hydrocarbon resin.

[0011] Furthermore, the dispersant is a block polymer dispersant containing acidic groups.

[0012] Furthermore, the leveling agent is an acrylate leveling agent.

[0013] Furthermore, the defoamer is an organosilicon defoamer, and the coupling agent is an epoxy-containing silane coupling agent.

[0014] Furthermore, the curing agent is a trimer curing agent.

[0015] A method for preparing a solvent-free polyurethane coating includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is completed, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use. Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use; Step S3, Mixing: Component A and Component B are mixed according to the designed mass ratio to obtain a solvent-free polyurethane coating.

[0016] The advantages of this invention are: 1. Component A uses a combination of polyaspartic acid ester resin and hydroxyl acrylic resin. The polyaspartic acid ester resin itself is aliphatic and does not contain benzene rings and ester bonds that are degraded by ultraviolet light, which is beneficial to improving the structural stability of the resin. The polyurethane resin has excellent elasticity and bending resistance. When combined with a suitable curing agent, it completes the cross-linking and curing reaction to form a stable resin cross-linking structure. It does not require the use of a large amount of organic solvents, reducing VOC emissions during preparation and film formation. The coating has an ultra-high volume solids content and can form a film of 90~150um in one go, which improves the film thickness and quality. Moreover, the large single film thickness eliminates the need for repeated coatings, greatly reducing the difficulty of construction.

[0017] 2. Anti-settling agents adsorb onto the surfaces of titanium dioxide and barium sulfate, increasing interparticle friction and supporting particle suspension, thus preventing the coating from having a clear upper layer and a sedimentary lower layer; dispersants increase the electrostatic repulsion between powder fillers, breaking up the powder agglomerates of titanium dioxide and barium sulfate; defoamers can quickly penetrate into the liquid film of bubbles, disrupting the stability of the liquid film and causing bubbles generated during stirring to break up quickly; leveling agents reduce the tension of the coating and improve its fluidity; coupling agents connect fillers and organic resins, improving the interfacial adhesion between fillers and resins. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the steps involved in the preparation of a solvent-free polyurethane coating. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below. Example 1:

[0020] A solvent-free polyurethane coating comprising component A and component B.

[0021] Component A comprises raw materials in parts by mass: Polyaspartic acid ester resin, 40 parts. The secondary amine group -NH- equivalent in the polyaspartic acid ester resin is 290 eq, and the viscosity is 900~2000 (mpa.s / 25℃).

[0022] Hydroxyacrylate resin, 10 parts. The hydroxyl content of the hydroxyacrylate resin is 82.5 eq, and the solid content is 90%.

[0023] Non-reactive diluent, specifically hydrocarbon resin, 10 parts.

[0024] The anti-settling agent is BP-184 organic bentonite, 0.5 parts.

[0025] Dispersant, specifically a block polymer dispersant containing acidic groups (model WE-D232S), 1 part.

[0026] Defoamer, specifically silicone defoamer (model 6800 defoamer), 0.2 parts; Titanium dioxide, 25 parts.

[0027] Barium sulfate, 12 parts.

[0028] Leveling agent, specifically an acrylic leveling agent (model WE-D8772R), 0.3 parts.

[0029] Coupling agent, specifically an epoxy-containing silane coupling agent (model KH560), 1 part.

[0030] Component B includes a curing agent, a trimer curing agent (model HT600), 100 parts.

[0031] The prepared component A and component B are mixed in a mass ratio of 5:1 to obtain the coating.

[0032] Preparation methods of solvent-free polyurethane coatings, such as Figure 1 As shown, it includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide, and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is complete, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use.

[0033] Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use.

[0034] Step S3, Mixing: The solvent-free polyurethane coating is obtained by mixing component A and component B at a mass ratio of 5:1. Example 2:

[0035] A solvent-free polyurethane coating comprising component A and component B.

[0036] Component A comprises raw materials in parts by mass: Polyaspartic acid ester resin, 30 parts. The secondary amine group -NH- equivalent in the polyaspartic acid ester resin is 290 eq, and the viscosity is 900~2000 (mpa.s / 25℃).

[0037] Hydroxyacrylate resin, 5 parts. The hydroxyl content of the hydroxyacrylate resin is 82.5 eq, and the solid content is 90%.

[0038] Non-reactive diluent, specifically hydrocarbon resin, 10 parts.

[0039] The anti-settling agent is BP-184 organic bentonite, 0.5 parts.

[0040] Dispersant, specifically a block polymer dispersant containing acidic groups (model WE-D232S), 1 part.

[0041] Defoamer, specifically silicone defoamer (model 6800 defoamer), 0.2 parts; Titanium dioxide, 25 parts.

[0042] Barium sulfate, 27 parts.

[0043] Leveling agent, specifically an acrylic leveling agent (model WE-D8772R), 0.3 parts.

[0044] Coupling agent, specifically an epoxy-containing silane coupling agent (model KH560), 1 part.

[0045] Component B includes a curing agent, a trimer curing agent (model HT600), 100 parts.

[0046] The prepared component A and component B are mixed in a mass ratio of 5:1 to obtain the coating.

[0047] Preparation methods of solvent-free polyurethane coatings, such as Figure 1 As shown, it includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide, and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is complete, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use.

[0048] Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use.

[0049] Step S3, Mixing: The solvent-free polyurethane coating is obtained by mixing component A and component B at a mass ratio of 5:1.

[0050] The prepared component A and component B are mixed in a mass ratio of 7:1 to obtain the coating.

[0051] Preparation methods of solvent-free polyurethane coatings, such as Figure 1 As shown, it includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide, and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is complete, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use.

[0052] Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use.

[0053] Step S3, Mixing: The solvent-free polyurethane coating is obtained by mixing component A and component B at a mass ratio of 7:1. Example 3:

[0054] A solvent-free polyurethane coating comprising component A and component B.

[0055] Component A comprises raw materials in parts by mass: Polyaspartic acid ester resin, 45 parts. The secondary amine group -NH- equivalent in the polyaspartic acid ester resin is 290 eq, and the viscosity is 900~2000 (mpa.s / 25℃).

[0056] Hydroxyacrylate resin, 5 parts. The hydroxyl content of the hydroxyacrylate resin is 82.5 eq, and the solid content is 90%.

[0057] Non-reactive diluent, specifically hydrocarbon resin, 12 parts.

[0058] The anti-settling agent is BP-184 organic bentonite, 0.5 parts.

[0059] Dispersant, specifically a block polymer dispersant containing acidic groups (model WE-D232S), 1 part.

[0060] Defoamer, specifically silicone defoamer (model 6800 defoamer), 0.2 parts; Titanium dioxide, 25 parts.

[0061] Barium sulfate, 9.5 parts.

[0062] Leveling agent, specifically an acrylic leveling agent (model WE-D8772R), 0.3 parts.

[0063] The coupling agent, specifically an epoxy-containing silane coupling agent (model KH560), is 1.5 parts.

[0064] Component B includes a curing agent, a trimer curing agent (model HT600), 100 parts.

[0065] The prepared component A and component B are mixed in a mass ratio of 4:1 to obtain the coating.

[0066] Preparation methods of solvent-free polyurethane coatings, such as Figure 1 As shown, it includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide, and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is complete, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use.

[0067] Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use.

[0068] Step S3, Mixing: The solvent-free polyurethane coating is obtained by mixing component A and component B at a mass ratio of 4:1.

[0069] Product performance testing: Experimental group: Coating products obtained in Examples 1, 2, and 3.

[0070] Experimental results: See Table 1 for details.

[0071] Table 1 in conclusion: 1. The coating has an average non-volatile content of 99.3%, reducing VOC pollution from the coating.

[0072] 2. The coating adhesion exceeds the standard by about 4 MPa. The coating shows no cracks in the bending test, indicating good bending resistance. The impact resistance test data are all greater than the target of 50 kg, and the abrasion resistance test data are all less than or equal to 0.1 g, indicating good mechanical properties.

[0073] 3. In the water resistance test of the coating, the coating showed no damage within 7 days. In the gasoline resistance test of the coating, the coating did not show any blistering, peeling, rusting or cracking.

[0074] 4. The surface drying time of the coating is less than or equal to 4 hours, and the actual drying time of the coating is less than or equal to 24 hours. The coating can be rapidly cooled and set.

[0075] 5. The coating has a salt spray resistance of over 1000 hours, with an average of 1210 hours. The coating remains intact for 30 days in an alkaline environment and for 30 days in an acidic environment.

[0076] In summary, the coating does not require solvents, thus avoiding VOC emissions caused by solvent evaporation during film formation and preparation. It also avoids the situation where coating evaporation affects the solid content of the coating, ensuring that the formed coating has good film quality.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A solvent-free polyurethane coating, characterized in that, Includes component A and component B; Component A comprises raw materials in parts by mass: Polyaspartic acid ester resin, 30-50 parts; Hydroxy acrylic resin, 5-15 parts; Non-reactive diluent, 5-30 parts; Anti-settling agent, 0.5-3 parts; Dispersant, 1-5 parts; Defoamer, 0.1 to 1 part; Titanium dioxide, 10-30 parts; Barium sulfate, 5-40 parts; Leveling agent, 0.1~1 part; Coupling agent, 1-5 parts; Component B comprises raw materials in parts by mass: Hardener, 100 parts.

2. The solvent-free polyurethane coating according to claim 1, characterized in that: The mass ratio of component A to component B is in the range of 3 to 8:

1.

3. The solvent-free polyurethane coating according to claim 1, characterized in that: The polyaspartic acid ester resin has a secondary amine group -NH- equivalent of 290 eq and a viscosity of 900~2000 (mpa.s / 25℃).

4. The solvent-free polyurethane coating according to claim 1, characterized in that: The hydroxyl acrylic resin has a hydroxyl content of 82.5 eq and a solid content of 90%.

5. The solvent-free polyurethane coating according to claim 1, characterized in that: The anti-settling agent is organic bentonite, and the inactive diluent is a hydrocarbon resin.

6. The solvent-free polyurethane coating according to claim 1, characterized in that: The dispersant is a block polymer dispersant containing acidic groups.

7. The solvent-free polyurethane coating according to claim 1, characterized in that: The leveling agent is an acrylate leveling agent.

8. The solvent-free polyurethane coating according to claim 1, characterized in that: The defoamer is an organosilicon defoamer, and the coupling agent is an epoxy-containing silane coupling agent.

9. The solvent-free polyurethane coating according to claim 1, characterized in that: The curing agent is a trimer curing agent.

10. A method for preparing a solvent-free polyurethane coating as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S1, Preparation of Component A: In a dry and clean jacketed reactor, polyaspartic acid ester resin, hydroxyl acrylic resin, and non-reactive diluent are added according to the design ratio and stirred. The stirring speed is controlled at 600~1200 r / min and the stirring time is controlled at 10~30 min. After stirring evenly, anti-settling agent, dispersant, defoamer, titanium dioxide and barium sulfate are added and stirred. The stirring speed is controlled at 1000~1500 r / min and the stirring time is controlled at 30~60 min. After stirring is completed, the material is sent to a sand mill to grind to a fineness of ≤20μm to obtain a slurry. A coupling agent is added to the slurry and the stirring speed is controlled at 500~800 r / min. After mixing evenly, component A is obtained for later use. Step S2, Preparation of Component B: Prepare the curing agent to obtain component B for later use; Step S3, Mixing: Component A and Component B are mixed according to the designed mass ratio to obtain a solvent-free polyurethane coating.

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