Cathode electrophoretic coating with bio-based tall oil acid modified acrylic acid and preparation method of cathode electrophoretic coating

Abstract

The invention discloses a preparation method of a cathode electrophoretic coating with bio-based tall oil acid modified acrylic acid. The preparation method comprises the following steps: S1, synthesizing acrylic resin taking glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and 2-ethylhexyl acrylate as monomers; s2, mixing the bio-based tall oil acid with polyamine to prepare tall oil amide; s3, the acrylic resin prepared in the step S1 and the tall oil amide prepared in the step S2 continue to react, then a curing agent and a neutralizing agent are added, and the bio-based tall oil acid modified acrylic cathode electrophoretic coating is prepared. The modified acrylic electrophoretic coating prepared by the method has weather resistance and salt fog resistance at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of electrophoretic coatings, and in particular to a bio-based tall oil acid-modified acrylic acid cathode electrophoretic coating and a preparation method thereof. Background Art

[0002] As a kind of water-based coating, electrophoretic coating has the characteristics of low pollution and green environmental protection. It is easy to realize mechanized and automated production, and is suitable for coating workpieces with complex shapes, edges and corners, and holes. Electrophoretic coatings are mostly based on epoxy resins, which mainly play an anti-corrosion role and protect the metal substrate. In addition, some of them need to have weather resistance, and no second layer of coating is sprayed after the primer. Since epoxy resin coating itself is not weather-resistant, acrylic resin coating is needed to achieve weather resistance. It is necessary to meet weather resistance and salt spray resistance at the same time to achieve the effect of bottom and surface integration. Due to the lack of rigid groups and the lack of more polar groups compared to epoxy resin, especially the larger the molecular weight of acrylic resin, the worse the wetting. Therefore, ordinary acrylic resin electrophoretic coatings have poor adhesion to the substrate, and then poor salt spray resistance. It is also easy to have construction problems during the electrophoresis process, and the paint film has defects such as pinholes and accumulation.

[0003] Acrylic resin electrophoretic coating needs to be modified to increase the wettability of the coating on the surface of the metal substrate and increase the adhesion between the paint film and the substrate, thereby improving the corrosion resistance and making the modified acrylic electrophoretic coating both weather-resistant and salt spray-resistant. Summary of the invention

[0004] The object of the present invention is to provide a bio-based tall oil acid modified acrylic cathodic electrophoretic coating and a preparation method thereof, so as to solve one or more of the above-mentioned prior art problems.

[0005] On the one hand, the present invention provides a method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating, comprising the following steps:

[0006] S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers;

[0007] S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide;

[0008] S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

[0009] In certain embodiments, the acrylic resin in step S1 is prepared by including the following components in parts by weight:

[0010]

[0011] In certain embodiments, the organic solvent is a ketone solvent, an alcohol ether solvent, toluene, xylene or isopropanol.

[0012] In certain embodiments, the synthesis method of the acrylic resin in step S1 is:

[0013] Add a formulated amount of organic solvent into a reaction container, stir the reaction monomer and initiator BPO evenly in a monomer tank, wait for the organic solvent in the reaction container to heat up to 80-90°C, start dripping the mixture of monomer and initiator BPO, keep the dripping temperature at 80-90°C, and keep the dripping time at 2.5-3.5h; after the dripping is completed, continue to control the temperature at 80-90°C and keep it warm for 1h-2h to obtain acrylic resin.

[0014] In certain embodiments, the molar ratio of bio-based tall oil acid to polyamine is 1:(1-3).

[0015] In certain embodiments, the synthesis method of tall oil amide in step S2 is:

[0016] Under nitrogen protection, bio-based tall oil acid and polyamine are added to a reaction container respectively, heated to 140-160° C. for reaction for 3-5 hours, and then purified to obtain tall oil amide.

[0017] In certain embodiments, the bio-based tall oil acid-modified acrylic cathodic electrophoretic coating in step S3 includes the following components in parts by weight:

[0018]

[0019] In certain embodiments, the synthesis method of the bio-based tall oil acid-modified acrylic cathodic electrophoretic coating in step S3 is:

[0020] a. Add tall oil amide from step S2 and acrylic resin from step S1 into a reaction vessel, raise the temperature to 110-130°C, and keep warm for 1.5-4h;

[0021] b. After cooling to 90°C, add the blocked curing agent and stir for 1-2 hours;

[0022] c. After adding the neutralizer, continue stirring for 1-2 hours, and after adding pure water, stir for 1-2 hours to obtain the acrylic cathode electrophoretic coating.

[0023] In certain embodiments, the blocked curing agent is an aliphatic isocyanate, an alicyclic isocyanate or an aromatic isocyanate, and the blocking agent is an alcohol ether solvent or a ketoxime solvent; the alcohol ether solvent is at least one of ethylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol hexyl ether, and the ketoxime solvent is at least one of acetone oxime and butanone oxime;

[0024] The neutralizing agent is at least one of formic acid, acetic acid, aminosulfonic acid and methanesulfonic acid.

[0025] On the other hand, the present invention provides a bio-based tall oil acid modified acrylic cathodic electrophoretic coating, which is prepared by the following preparation method:

[0026] S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers;

[0027] S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide;

[0028] S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

[0029] In summary, the present invention has the following beneficial effects:

[0030] 1. By introducing tall oil amide into acrylic resin, the interaction between the substrates is increased, the interfacial energy between the solid and the liquid is reduced, and the wettability of the acrylic electrophoretic coating on the metal substrate is significantly improved, thereby improving the actual construction performance;

[0031] 2. The polarity of tall oil amide improves the adhesion between the coating and the substrate, thereby enhancing the anti-corrosion performance of the coating, making it both weather-resistant and salt spray-resistant, and expanding its application range;

[0032] 3. The use of bio-based tall oil amide improves the environmental performance of the coating. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below through embodiments.

[0034] Example 1

[0035] A bio-based tall oil acid-modified acrylic cathodic electrophoretic coating is prepared by the following preparation method:

[0036] S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers;

[0037] S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide;

[0038] S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

[0039] The synthesis method of acrylic resin in step S1 is:

[0040] Add a formulated amount of organic solvent into the reaction container, stir the reaction monomer and initiator BPO evenly in the monomer tank, wait for the organic solvent in the reaction container to heat up to 80°C, start to drop the mixture of monomer and initiator BPO, keep the dropping temperature at 80°C, and keep the dropping time at 2.5h; after the dropping is completed, continue to control the temperature at 80°C and keep it warm for 1h to obtain acrylic resin.

[0041] Wherein: the acrylic resin in step S1 is prepared by comprising the following components in parts by weight:

[0042]

[0043] The organic solvent is a ketone solvent, an alcohol ether solvent, toluene, xylene or isopropanol.

[0044] The synthesis method of tall oil amide in step S2 is:

[0045] Under nitrogen protection, bio-based tall oil acid and polyamine were added to a reaction vessel respectively, heated to 140° C. for reaction for 3 h, and then purified to obtain tall oil amide.

[0046] Wherein: the molar ratio of bio-based tall oil acid to polyamine is 1:1.

[0047] The synthesis method of the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 is:

[0048] a. Add tall oil amide from step S2 and acrylic resin from step S1 into a reaction vessel, raise the temperature to 110°C, and keep warm for 1.5h;

[0049] b. After cooling to 90°C, add the blocked curing agent and stir for 1 hour;

[0050] c. After adding the neutralizer, continue stirring for 1 hour, and after adding pure water, stir for 1 hour to obtain the acrylic cathode electrophoretic coating.

[0051] Wherein: the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 comprises the following components in parts by weight:

[0052]

[0053] The blocked curing agent is formed by the reaction of HDI trimer and methyl ethyl ketone oxime at 80°C;

[0054] The neutralizing agent is at least one of formic acid, acetic acid, aminosulfonic acid and methanesulfonic acid.

[0055] Based on the above preparation method, a bio-based tall oil acid modified acrylic cathodic electrophoretic coating was produced, mixed with HLS black slurry, placed in an electrophoretic tank for aging for 24 hours, with a tank temperature of 30°C, a controlled voltage of 190V, electrophoresis for 60s, and then baked at 180°C for 20min to obtain a paint film with good appearance.

[0056] Example 2

[0057] A bio-based tall oil acid-modified acrylic cathodic electrophoretic coating is prepared by the following preparation method:

[0058] S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers;

[0059] S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide;

[0060] S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

[0061] The synthesis method of acrylic resin in step S1 is:

[0062] Add a formulated amount of organic solvent into the reaction container, stir the reaction monomer and initiator BPO evenly in the monomer tank, wait for the organic solvent in the reaction container to heat up to 85°C, start to drop the mixture of monomer and initiator BPO, keep the dropping temperature at 85°C, and keep the dropping time at 3.0h; after the dropping is completed, continue to control the temperature at 85°C and keep it warm for 1.5h to obtain acrylic resin.

[0063] Wherein: the acrylic resin in step S1 is prepared by comprising the following components in parts by weight:

[0064]

[0065]

[0066] The organic solvent is a ketone solvent, an alcohol ether solvent, toluene, xylene or isopropanol.

[0067] The synthesis method of tall oil amide in step S2 is:

[0068] Under nitrogen protection, bio-based tall oil acid and polyamine were added to a reaction vessel respectively, heated to 150° C. for reaction for 4 hours, and then purified to obtain tall oil amide.

[0069] Wherein: the molar ratio of bio-based tall oil acid to polyamine is 1:2.

[0070] The synthesis method of the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 is:

[0071] a. Add tall oil amide from step S2 and acrylic resin from step S1 into a reaction vessel, raise the temperature to 120°C and keep warm for 2.5h;

[0072] b. After cooling to 90°C, add the blocked curing agent and stir for 1.5 hours;

[0073] c. After adding the neutralizer, stirring was continued for 1.5 hours, and after adding pure water, stirring was continued for 1.5 hours to obtain the acrylic cathode electrophoretic coating.

[0074] Wherein: the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 comprises the following components in parts by weight:

[0075]

[0076] The blocked curing agent is formed by the reaction of HDI trimer and methyl ethyl ketone oxime at 80°C;

[0077] The neutralizing agent is at least one of formic acid, acetic acid, aminosulfonic acid and methanesulfonic acid.

[0078] Based on the above preparation method, a bio-based tall oil acid modified acrylic cathodic electrophoretic coating was produced, mixed with HLS black slurry, placed in an electrophoretic tank for aging for 24 hours, with a tank temperature of 30°C, a controlled voltage of 190V, electrophoresis for 60s, and then baked at 180°C for 20min to obtain a paint film with good appearance.

[0079] Example 3

[0080] A bio-based tall oil acid-modified acrylic cathodic electrophoretic coating is prepared by the following preparation method:

[0081] S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers;

[0082] S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide;

[0083] S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

[0084] The synthesis method of acrylic resin in step S1 is:

[0085] Add a formulated amount of organic solvent into the reaction container, stir the reaction monomer and initiator BPO evenly in the monomer tank, wait for the organic solvent in the reaction container to heat up to 90°C, start to drop the mixture of monomer and initiator BPO, keep the dropping temperature at 90°C, and keep the dropping time at 3.5h; after the dropping is completed, continue to control the temperature at 90°C and keep it warm for 2h to obtain acrylic resin.

[0086] Wherein: the acrylic resin in step S1 is prepared by comprising the following components in parts by weight:

[0087]

[0088] The organic solvent is a ketone solvent, an alcohol ether solvent, toluene, xylene or isopropanol.

[0089] The synthesis method of tall oil amide in step S2 is:

[0090] Under nitrogen protection, bio-based tall oil acid and polyamine were added to a reaction vessel respectively, heated to 160° C. for reaction for 5 h, and then purified to obtain tall oil amide.

[0091] Wherein: the molar ratio of bio-based tall oil acid to polyamine is 1:3.

[0092] The synthesis method of the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 is:

[0093] a. Add tall oil amide from step S2 and acrylic resin from step S1 into a reaction vessel, raise the temperature to 130°C and keep warm for 4h;

[0094] b. After cooling to 90°C, add the blocked curing agent and stir for 2h;

[0095] c. After adding the neutralizer, continue stirring for 2 hours, and after adding pure water, stir for 2 hours to obtain the acrylic cathode electrophoretic coating.

[0096] Wherein: the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 comprises the following components in parts by weight:

[0097]

[0098]

[0099] The blocked curing agent is formed by the reaction of HDI trimer and methyl ethyl ketone oxime at 80°C;

[0100] The neutralizing agent is at least one of formic acid, acetic acid, aminosulfonic acid and methanesulfonic acid.

[0101] Based on the above preparation method, a bio-based tall oil acid modified acrylic cathodic electrophoretic coating was produced, mixed with HLS black slurry, placed in an electrophoretic tank for aging for 24 hours, with a tank temperature of 30°C, a controlled voltage of 190V, electrophoresis for 60s, and then baked at 180°C for 20min to obtain a paint film with good appearance.

[0102] The performance tests were conducted on the bath liquid and board surface, performance of the products in Examples 1-3 and the bath liquid and board surface of ordinary products. The relevant parameters are shown in Table 1:

[0103] Table 1

[0104]

[0105] As can be seen from Table 1, through the relevant tests that meet the standards and requirements, the wettability of the modified acrylic cathodic electrophoretic coating is significantly improved, and the salt spray resistance is significantly improved while maintaining the weather resistance.

[0106] In summary, the present invention has the following beneficial effects:

[0107] 1. By introducing tall oil amide into acrylic resin, the wettability of acrylic electrophoretic coating on metal substrate is significantly improved, and the actual construction performance is improved;

[0108] 2. The polarity of tall oil amide improves the adhesion between the coating and the substrate, thereby enhancing the anti-corrosion performance of the coating, making it both weather-resistant and salt spray-resistant, and expanding its application range;

[0109] 3. The use of bio-based tall oil amide improves the environmental performance of the coating.

[0110] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, and these should also be regarded as within the scope of protection of the invention.

Claims

1. A method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating, characterized in that: The following steps are involved: S1. Synthesize acrylic resin with glycidyl methacrylate, methyl methacrylate, styrene, butyl acrylate, hydroxyethyl methacrylate and isooctyl acrylate as monomers; S2, mixing bio-based tall oil acid and polyamine to prepare tall oil amide; S3, continuing to react the acrylic resin obtained in step S1 and the tall oil amide obtained in step S2, and then adding a curing agent and a neutralizing agent to obtain the bio-based tall oil acid modified acrylic cathodic electrophoretic coating.

2. The method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 1, characterized in that: In step S1, the acrylic resin is prepared by including the following components in parts by weight:

3. A method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 2, characterized in that: The organic solvent is a ketone solvent, an alcohol ether solvent, toluene, xylene or isopropanol.

4. A method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 2, characterized in that: The synthesis method of acrylic resin in step S1 is: Add a formulated amount of organic solvent into a reaction container, stir the reaction monomer and initiator BPO evenly in a monomer tank, wait for the organic solvent in the reaction container to heat up to 80-90°C, start dripping the mixture of monomer and initiator BPO, keep the dripping temperature at 80-90°C, and keep the dripping time at 2.5-3.5h; after the dripping is completed, continue to control the temperature at 80-90°C and keep it warm for 1h-2h to obtain acrylic resin.

5. A method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 1, characterized in that: The molar ratio of bio-based tall oil acid to polyamine is 1:(1-3).

6. The method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 5, characterized in that: The synthesis method of tall oil amide in step S2 is: Under nitrogen protection, bio-based tall oil acid and polyamine are added to a reaction container respectively, heated to 140-160° C. for reaction for 3-5 hours, and then purified to obtain tall oil amide.

7. The method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 1, characterized in that: In step S3, the bio-based tall oil acid-modified acrylic cathodic electrophoretic coating comprises the following components in parts by weight:

8. The method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 7, characterized in that: The synthesis method of the bio-based tall oil acid modified acrylic cathodic electrophoretic coating in step S3 is: a. Add tall oil amide from step S2 and acrylic resin from step S1 into a reaction vessel, raise the temperature to 110-130°C, and keep warm for 1.5-4h; b. After cooling to 90°C, add the blocked curing agent and stir for 1-2 hours; c. After adding the neutralizer, continue stirring for 1-2 hours, and after adding pure water, stir for 1-2 hours to obtain the acrylic cathode electrophoretic coating.

9. The method for preparing a bio-based tall oil acid modified acrylic cathodic electrophoretic coating according to claim 7, characterized in that: The blocked curing agent is an aliphatic isocyanate, an alicyclic isocyanate or an aromatic isocyanate, and the blocking agent is an alcohol ether solvent or a ketoxime solvent; the alcohol ether solvent is at least one of ethylene glycol butyl ether, propylene glycol methyl ether, ethylene glycol ethyl ether and ethylene glycol hexyl ether, and the ketoxime solvent is at least one of acetone oxime and butanone oxime; The neutralizing agent is at least one of formic acid, acetic acid, aminosulfonic acid and methanesulfonic acid.

10. A bio-based tall oil acid modified acrylic cathodic electrophoretic coating, characterized in that: The compound is prepared by the preparation method described in any one of claims 1 to 9.

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