High weatherable polyurethane coating and method of making same

Abstract

This invention discloses a high weather-resistant polyurethane coating, comprising the following raw materials in parts by weight: 50-70 parts of component A polyurethane coating, 30-40 parts of component B polyurethane coating, and 4-11 parts of weather-resistant additives. The invention also discloses a method for preparing the high weather-resistant polyurethane coating, comprising the following steps: S1, preparing component A polyurethane coating; S2, preparing component B polyurethane coating; S3, mixing component A and component B polyurethane coatings, placing them in a constant-temperature reactor, filling the reactor with inert gas, starting the reactor for stirring and heating, ensuring thorough mixing and reaction, stirring until homogeneous, adding the weather-resistant additives, mixing and stirring again, filtering, and then dispersing the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating. This method for preparing the high weather-resistant polyurethane coating combines cathodic electrophoretic coating technology with weathering technology and is suitable for surface coating of metal substrates.

Description

Technical Field

[0001] This invention relates to the field of electrophoretic coating technology, and in particular to a high weather-resistant polyurethane coating and its preparation method. Background Technology

[0002] Polyurethane (PU) possesses a series of excellent characteristics and surface properties, showing promising applications in antifouling coatings, biocompatible materials, and anti-corrosion coatings. Its core characteristic lies in the repeating urethane bonds (—NHCOO—) in its molecular chain. However, the hydrophilic groups (-CH2OH) on the polyurethane chain readily absorb water, leading to decreased water resistance and affecting the coating's corrosion protection effect. Two-component polyurethane coatings generally consist of a component (a hydroxyl resin containing —OH, such as acrylic polyols or polyester polyols) and a component (an isocyanate curing agent containing —NCO, such as IPDI trimer). The curing method involves mixing the two components before application and curing through the reaction of —NCO and —OH. This results in optimal performance (high weather resistance and high hardness), accounting for over 85% of high-end industrial applications. The introduction of fluorinated compounds leverages their low surface tension and low coefficient of friction, playing a crucial role in the preparation of hydrophobic surfaces. Polyurethane coatings are commonly used in industrial protection, automotive original / repair paints, wooden fixtures, and electronic product casing coatings. Summary of the Invention

[0003] The purpose of this invention is to provide a high weather-resistant polyurethane coating and its preparation method, thereby solving one or more of the problems in the prior art. On one hand, the present invention provides a high weather-resistant polyurethane coating comprising the following raw materials in parts by weight: Component A, polyurethane coating, 50-70 parts. Component B, polyurethane coating, 30-40 parts. 4-11 parts of weather-resistant additives.

[0004] In some embodiments, component A, the polyurethane coating, comprises the following raw materials in parts by weight: 50-55 parts of fluorinated hydroxyl acrylic resin, 0.1-0.2 parts of nano-alumina, Dispersant 0.3-0.5 parts, Leveling agent 0.3-0.5 parts, Defoamer 0.3-0.5 parts, Catalyst 0.05-0.07 parts.

[0005] In some embodiments, the fluorinated hydroxyl acrylic resin comprises the following raw materials in parts by weight: 2-5 parts of trifluorochloroethylene monomer 20-30 parts of styrene 40-50 parts of hydroxyethyl acrylate 20-25 parts of dimethylaminoethyl methacrylate 30-33 parts of butyl acrylate Solvent 20-25 parts.

[0006] In some embodiments, component A, the polyurethane coating, is prepared by the following method: a. Prepare a fluorinated hydroxy acrylic resin by mixing 2-5 parts of trifluorochloroethylene monomer, 20-30 parts of styrene, 40-50 parts of hydroxyethyl acrylate, 20-25 parts of dimethylaminoethyl methacrylate, 30-33 parts of butyl acrylate, and 20-25 parts of solvent. b. Add 0.1-0.2 parts of nano-alumina, 0.3-0.5 parts of dispersant, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of defoamer and 0.05-0.07 parts of catalyst to the fluorinated hydroxyl acrylic resin. After the reaction is complete, stir evenly to obtain component A polyurethane coating. In some embodiments, component B of the polyurethane coating comprises the following raw materials in parts by weight: 8-10 parts of isoflurane diisocyanate 6-10 parts of toluene diisocyanate 8-10 parts of diphenylmethane diisocyanate, 8-12 parts of fluoroethanol.

[0007] In some embodiments, component B polyurethane coating is prepared by the following method: Add 8-10 parts of isoflurane diisocyanate, 6-10 parts of toluene diisocyanate, 8-10 parts of diphenylmethane diisocyanate and 8-12 parts of fluoroethanol to a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, and after thorough mixing and reaction, stir evenly to obtain component B polyurethane coating.

[0008] In some embodiments, the weather-resistant agent is a mixture of nano-graphene and nano-zinc oxide in a mass ratio of (1-1.6):(1.5-2.8).

[0009] On the other hand, the method for preparing the high weather-resistant polyurethane coating provided by the present invention includes the following steps: S1. Preparation of component A polyurethane coating: a. Prepare a fluorinated hydroxy acrylic resin by mixing 2-5 parts of trifluorochloroethylene monomer, 20-30 parts of styrene, 40-50 parts of hydroxyethyl acrylate, 20-25 parts of dimethylaminoethyl methacrylate, 30-33 parts of butyl acrylate, and 20-25 parts of solvent. b. Add 0.1-0.2 parts of nano-alumina, 0.3-0.5 parts of dispersant, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of defoamer and 0.05-0.07 parts of catalyst to the fluorinated hydroxyl acrylic resin. After the reaction is complete, stir evenly to obtain component A polyurethane coating. S2. Preparation of component B polyurethane coating: Add 8-10 parts of isoflurone diisocyanate, 6-10 parts of toluene diisocyanate, 8-10 parts of diphenylmethane diisocyanate and 8-12 parts of fluoroethanol to a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, and after thorough mixing and reaction, stir evenly to obtain component B polyurethane coating. S3. Mix component A polyurethane coating and component B polyurethane coating, put them into a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, mix thoroughly and stir evenly after reaction, then add weather-resistant additives, mix and stir again, filter, and disperse the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating. Beneficial effects: The preparation method of the high weather-resistant polyurethane coating of the present invention, combined with the cathodic electrophoretic coating process, is suitable for surface coating of metal substrates and has high mechanical properties and high weather resistance. Detailed Implementation

[0010] The present invention will be further described in detail below through embodiments.

[0011] A high weather-resistant polyurethane coating comprises the following raw materials in parts by weight: 60 parts of component A polyurethane coating, 35 parts of component B polyurethane coating, and 10 parts of weather-resistant additives.

[0012] The weather-resistant additive is a mixture of nano-graphene and nano-zinc oxide in a mass ratio of 1:2.5.

[0013] Component A, the polyurethane coating, is prepared by the following method: A fluorinated hydroxy acrylic resin was prepared by mixing 5 parts of trifluorochloroethylene monomer, 20 parts of styrene, 50 parts of hydroxyethyl acrylate, 20 parts of dimethylaminoethyl methacrylate, 30 parts of butyl acrylate, and 20 parts of solvent. 50 parts of the fluorinated hydroxy acrylic resin were then mixed thoroughly with 0.2 parts of nano-alumina, 0.3 parts of dispersant, 0.3 parts of leveling agent, 0.3 parts of defoamer, and 0.07 parts of catalyst. After the mixture was fully stirred and reacted, component A (polyurethane coating) was obtained.

[0014] Component B, the polyurethane coating, is prepared by the following method: 10 parts of isophorone diisocyanate, 10 parts of toluene diisocyanate, 8 parts of diphenylmethane diisocyanate, and 8 parts of fluoroethanol were added to a constant temperature reactor, and inert gas was filled into the reactor. The reactor was started to stir and heated to 80°C. After thorough mixing and reaction, the polyurethane coating of component B was obtained.

[0015] A method for preparing a high weather-resistant polyurethane coating includes the following preparation steps: S1, Component A polyurethane coating Component A, the polyurethane coating, comprises the following components in parts by weight: 5 parts trifluorochloroethylene monomer, 20 parts styrene, 35 parts hydroxyethyl acrylate, 20 parts dimethylaminoethyl methacrylate, 30 parts butyl acrylate, and 20 parts solvent; A fluorinated hydroxy acrylic resin was prepared by mixing 5 parts of trifluorochloroethylene monomer, 20 parts of styrene, 50 parts of hydroxyethyl acrylate, 20 parts of dimethylaminoethyl methacrylate, 30 parts of butyl acrylate, and 20 parts of solvent. 50 parts of the fluorinated hydroxy acrylic resin were then mixed thoroughly with 0.2 parts of nano-alumina, 0.3 parts of dispersant, 0.3 parts of leveling agent, 0.3 parts of defoamer, and 0.07 parts of catalyst. After the mixture was fully stirred and reacted, component A polyurethane coating was obtained. S2, Component B polyurethane coating Component B, the polyurethane coating, comprises the following components in parts by weight: 10 parts isoflurane diisocyanate, 10 parts toluene diisocyanate, 8 parts diphenylmethane diisocyanate, 8 parts fluoroethanol; 10 parts of isoflurane diisocyanate, 10 parts of toluene diisocyanate, 8 parts of diphenylmethane diisocyanate, and 8 parts of fluoroethanol were added to a constant temperature reactor, and inert gas was filled into the reactor. The reactor was started to stir and heated to 80°C. After thorough mixing and reaction, the mixture was stirred evenly to obtain component B polyurethane coating. S3. Mix 60 parts of component A polyurethane coating with 35 parts of component B polyurethane coating, put them into a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, mix thoroughly and stir evenly after reaction, then add 10 parts of weather-resistant additive, mix and stir again, filter, and disperse the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating.

[0016] Example 2 A high weather-resistant polyurethane coating comprises the following raw materials in parts by weight: 55 parts of component A polyurethane coating, 30 parts of component B polyurethane coating, and 5 parts of weather-resistant additives.

[0017] The weather-resistant additive is a mixture of nano-graphene and nano-zinc oxide in a mass ratio of 1:1.5.

[0018] Component A, the polyurethane coating, is prepared by the following method: A fluorinated hydroxy acrylic resin was prepared by mixing 3 parts trifluorochloroethylene monomer, 25 parts styrene, 45 parts hydroxyethyl acrylate, 23 parts dimethylaminoethyl methacrylate, 32 parts butyl acrylate, and 22 parts solvent. 55 parts of the fluorinated hydroxy acrylic resin were then mixed thoroughly with 0.15 parts nano-alumina, 0.32 parts dispersant, 0.3 parts leveling agent, 0.33 parts defoamer, and 0.05 parts catalyst. After the mixture was fully stirred and reacted, component A polyurethane coating was obtained.

[0019] Component B, the polyurethane coating, is prepared by the following method: Eight parts of isophorone diisocyanate, nine parts of toluene diisocyanate, ten parts of diphenylmethane diisocyanate, and ten parts of fluoroethanol were added to a constant-temperature reactor, and inert gas was filled into the reactor. The reactor was started to stir and heated to 80°C. After thorough mixing and reaction, the polyurethane coating of component B was obtained.

[0020] A method for preparing a high weather-resistant polyurethane coating includes the following preparation steps: S1, Component A polyurethane coating Component A, the polyurethane coating, comprises the following components in parts by weight: 3 parts trifluorochloroethylene monomer, 25 parts styrene, 45 parts hydroxyethyl acrylate, 23 parts dimethylaminoethyl methacrylate, 32 parts butyl acrylate, and 22 parts solvent; S2, Component B polyurethane coating Component B, the polyurethane coating, comprises the following components in parts by weight: Mix 8 parts isoflurone diisocyanate, 9 parts toluene diisocyanate, 10 parts diphenylmethane diisocyanate, and 10 parts fluoroethanol. S3. Mix 55 parts of component A polyurethane coating with 30 parts of component B polyurethane coating, put them into a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, mix thoroughly and stir evenly after reaction, then add 5 parts of weather-resistant additive, mix and stir again, filter, and disperse the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating.

[0021] Example 3 A high weather-resistant polyurethane coating comprises the following raw materials in parts by weight: 50 parts of component A polyurethane coating and 30 parts of component B polyurethane coating.

[0022] Component A, the polyurethane coating, is prepared by the following method: A fluorinated hydroxy acrylic resin was prepared by mixing 20 parts styrene, 40 parts hydroxyethyl acrylate, 20 parts dimethylaminoethyl methacrylate, 30 parts butyl acrylate, and 20 parts solvent. 50 parts of the hydroxy acrylic resin were then mixed thoroughly with 0.3 parts dispersant, 0.3 parts leveling agent, 0.3 parts defoamer, and 0.05 parts catalyst. After the mixture was fully stirred and reacted, component A polyurethane coating was obtained.

[0023] Component B, the polyurethane coating, is prepared by the following method: 10 parts of isoflurane diisocyanate, 10 parts of toluene diisocyanate, 8 parts of diphenylmethane diisocyanate, and 8 parts of methyl isobutyl ketone were added to a constant temperature reactor, and inert gas was filled into the reactor. The reactor was started to stir and heated to 80°C. After thorough mixing and reaction, the mixture was stirred evenly to obtain component B polyurethane coating.

[0024] A method for preparing a high weather-resistant polyurethane coating includes the following preparation steps: S1, Component A polyurethane coating Component A, the polyurethane resin, comprises the following components in parts by weight: 20 parts styrene, 40 parts hydroxyethyl acrylate, 20 parts dimethylaminoethyl methacrylate, 30 parts butyl acrylate, 20 parts solvent; S2, Component B polyurethane coating Component B, the polyurethane resin, comprises the following components in parts by weight: Mix 10 parts isoflurane diisocyanate, 10 parts toluene diisocyanate, 8 parts diphenylmethane diisocyanate, and 8 parts methyl isobutyl ketone. S3. Mix 50 parts of component A polyurethane coating with 30 parts of component B polyurethane coating, put them into a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, mix thoroughly and stir evenly after reaction, filter and disperse the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating.

[0025] Compare with Example 1: Commercially available industrial protective grade fluorocarbon modified polyurethane coatings.

[0026] Compare with Example 2: Commercially available high-solids polyurethane marine coatings. Compare with Example 3: Commercially available polyurethane for automotive repair.

[0027] Performance testing The following performance tests were performed on the products of Examples 1-3 and Comparative Examples 1-3:

[0028] In summary, compared with existing similar products, the high weather-resistant polyurethane coating of the present invention, through precise compounding of components and combination with weather-resistant materials, achieves high mechanical properties and high weather resistance while maintaining environmental friendliness.

[0029] Specifically: (1) Weather resistance: In Examples 1 and 2, the fluoropolymer and fluorinated isocyanate curing agent work synergistically, and with the addition of weather-resistant additives, the salt spray resistance is better than that of Example 3 and Control Examples 1-3; (2) Mechanical properties: The hardness of both Examples 1 and 2 reached 2H, and their impact resistance and elongation at break were superior to those of Control Examples 1-3. The fluorinated hydroxyl acrylic resin, through the introduction of trifluorochloroethylene monomer copolymerization, enriched fluorine on the coating surface, which significantly reduced the surface energy (contact angle > 110°). At the same time, isoflurane diisocyanate has high hardness and excellent solvent resistance. The combination of the two can improve the tensile strength, elongation at break and hardness of the film after film formation. (3) Experiments showed that the performance of Example 2 was better than that of Example 1, indicating that the content of nano silica plays a key role in the weather resistance and self-healing performance of the paint film. The higher the content of nano silica, the better the weather resistance and self-healing performance of the paint film.

[0030] In summary, the preparation method of the weather-resistant self-healing coating of the present invention combines cathodic electrophoretic coating process with weather-resistant self-healing technology, and is suitable for surface coating of metal substrates. It has the characteristics of strong self-healing, strong environmental protection and excellent coating performance.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these should also be considered within the scope of protection of the invention.

Claims

1. A high weather-resistant polyurethane coating, characterized in that, Including the following parts by weight of raw materials: Component A, polyurethane coating, 50-70 parts. Component B, polyurethane coating, 30-40 parts. 4-11 parts of weather-resistant additives.

2. The high weather-resistant polyurethane coating according to claim 1, characterized in that, Component A, the polyurethane coating, comprises the following raw materials in parts by weight: 50-55 parts of fluorinated hydroxyl acrylic resin, 0.1-0.2 parts of nano-alumina, Dispersant 0.3-0.5 parts, Leveling agent 0.3-0.5 parts, Defoamer 0.3-0.5 parts, Catalyst 0.05-0.07 parts.

3. The high weather-resistant polyurethane coating according to claim 1, characterized in that, Fluorinated hydroxyl acrylic resin comprises the following raw materials in parts by weight: 2-5 parts of trifluorochloroethylene monomer 20-30 parts of styrene 40-50 parts of hydroxyethyl acrylate 20-25 parts of dimethylaminoethyl methacrylate 30-33 parts of butyl acrylate Solvent 20-25 parts.

4. The high weather-resistant polyurethane coating according to claim 1, characterized in that, Component A, the polyurethane coating, is prepared by the following method: a. Prepare a fluorinated hydroxy acrylic resin by mixing 2-5 parts of trifluorochloroethylene monomer, 20-30 parts of styrene, 40-50 parts of hydroxyethyl acrylate, 20-25 parts of dimethylaminoethyl methacrylate, 30-33 parts of butyl acrylate, and 20-25 parts of solvent. b. Add 0.1-0.2 parts of nano-alumina, 0.3-0.5 parts of dispersant, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of defoamer and 0.05-0.07 parts of catalyst to the fluorinated hydroxyl acrylic resin. After the reaction is complete, stir evenly to obtain component A polyurethane coating.

5. The high weather-resistant polyurethane coating according to claim 1, characterized in that, Component B, the polyurethane coating, comprises the following raw materials in parts by weight: 8-10 parts of isoflurane diisocyanate 6-10 parts of toluene diisocyanate 8-10 parts of diphenylmethane diisocyanate, 8-12 parts of fluoroethanol.

6. The high weather-resistant polyurethane coating according to claim 1, characterized in that, Component B polyurethane coating is prepared by the following method: Add 8-10 parts of isoflurane diisocyanate, 6-10 parts of toluene diisocyanate, 8-10 parts of diphenylmethane diisocyanate and 8-12 parts of fluoroethanol to a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, and after thorough mixing and reaction, stir evenly to obtain component B polyurethane coating.

7. The high weather-resistant polyurethane coating according to claim 1, characterized in that, The weather-resistant additive is a mixture of nano-graphene and nano-zinc oxide in a mass ratio of (1-1.6):(1.5-2.8).

8. A method for preparing the high weather-resistant polyurethane coating according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Preparation of component A polyurethane coating: a. Prepare a fluorinated hydroxy acrylic resin by mixing 2-5 parts of trifluorochloroethylene monomer, 20-30 parts of styrene, 40-50 parts of hydroxyethyl acrylate, 20-25 parts of dimethylaminoethyl methacrylate, 30-33 parts of butyl acrylate, and 20-25 parts of solvent. b. Add 0.1-0.2 parts of nano-alumina, 0.3-0.5 parts of dispersant, 0.3-0.5 parts of leveling agent, 0.3-0.5 parts of defoamer and 0.05-0.07 parts of catalyst to the fluorinated hydroxyl acrylic resin. After the reaction is complete, stir evenly to obtain component A polyurethane coating. S2. Preparation of component B polyurethane coating: Add 8-10 parts of isoflurone diisocyanate, 6-10 parts of toluene diisocyanate, 8-10 parts of diphenylmethane diisocyanate and 8-12 parts of fluoroethanol to a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, and after thorough mixing and reaction, stir evenly to obtain component B polyurethane coating. S3. Mix component A polyurethane coating and component B polyurethane coating, put them into a constant temperature reactor, fill the reactor with inert gas, start the reactor to stir and heat to 80°C, mix thoroughly and stir evenly after reaction, then add weather-resistant additives, mix and stir again, filter, and disperse the coating using a high-speed disperser to obtain the desired high weather-resistant polyurethane coating.

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