阅读说明：本技术 一种有色电泳涂料及其制备方法 (Colored electrophoretic paint and preparation method thereof ) 是由 林乾隆 林群超 葛丽珠 于 2020-11-11 设计创作，主要内容包括：本发明涉及一种有色电泳涂料及其制备方法,包括以下质量份的组分：丙烯酸树脂25-35份,氨基树脂15-30份,颜料0.6-5份,磷酸锆1-2份,中和剂1.5-3.5份,有机溶剂0.3-1份,去离子水30-50份,其中,颜料为聚羧酸盐改性的颜料,磷酸锆的平均粒径为50-150nm。本发明的有色电泳涂料加入聚羧酸盐改性的颜料和磷酸锆,可大大改善颜料的分散性,且磷酸锆还大大提高耐候性,同时改性颜料、磷酸锆与丙烯酸树脂、氨基树脂相容性好、稳定性好,避免了色差、漆膜表面粗糙的弊端。(The invention relates to a colored electrophoretic paint and a preparation method thereof, wherein the colored electrophoretic paint comprises the following components in parts by mass: 25-35 parts of acrylic resin, 15-30 parts of amino resin, 0.6-5 parts of pigment, 1-2 parts of zirconium phosphate, 1.5-3.5 parts of neutralizing agent, 0.3-1 part of organic solvent and 30-50 parts of deionized water, wherein the pigment is polycarboxylate modified pigment, and the average particle size of the zirconium phosphate is 50-150 nm. The polycarboxylate modified pigment and the zirconium phosphate are added into the colored electrophoretic paint, so that the dispersibility of the pigment can be greatly improved, the weather resistance of the zirconium phosphate is also greatly improved, and meanwhile, the modified pigment, the zirconium phosphate, the acrylic resin and the amino resin have good compatibility and good stability, and the defects of color difference and rough surface of a paint film are avoided.)

1. A colored electrophoretic paint is characterized in that: the paint comprises the following components in parts by mass:

25-35 parts of acrylic resin

15-30 parts of amino resin

0.6-5 parts of pigment

1-2 parts of zirconium phosphate

1.5-3.5 parts of neutralizing agent

0.3-1 part of organic solvent

30-50 parts of deionized water

Wherein the pigment is polycarboxylate modified pigment, and the average particle size of the zirconium phosphate is 50-150 nm.

2. The colored electrocoating paint of claim 1, wherein: the average particle size of the zirconium phosphate is 100 nm.

3. The colored electrocoating paint of claim 1, wherein: the acrylic resin is hydroxyl acrylic resin.

4. The colored electrocoating paint of claim 1, wherein: the amino resin comprises methylated melamine resin and butylated melamine resin, and the mass ratio of the methylated melamine resin to the butylated melamine resin is 1-2: 1-3.

5. The colored electrocoating paint of claim 1, wherein: the average particle size of the pigment is 10-15 nm.

6. The colored electrocoating paint of claim 1, wherein: the polycarboxylate is obtained by copolymerization of a comonomer under the action of an initiator and under the stirring condition, wherein the comonomer is methacrylic acid and sodium allylsulfonate, and the molar ratio of the methacrylic acid to the sodium allylsulfonate is 3-5: 0.5 to 1; the copolymerization reaction temperature is 70-90 ℃, and the time is 2.5-3.5 h.

7. The colored electrocoating paint of claim 1, wherein: the neutralizing agent is one or more of N-methyldiethanolamine, N' -dimethylethanolamine and triethylamine.

8. The colored electrocoating paint of claim 1, wherein: the solvent is one or more of isopropanol, ethylene glycol ethyl ether and n-butyl ether.

9. A preparation method of the colored electrophoretic paint is characterized by comprising the following steps: the method comprises the following steps:

(1) fully mixing acrylic resin, pigment and zirconium phosphate, and uniformly stirring in a sand grinding dispersion machine;

(2) adding a neutralizer into the step (1), uniformly stirring, adding amino resin, and stirring at a high speed;

(3) and finally, sequentially adding an organic solvent and deionized water, uniformly stirring and grinding until the fineness of the coating is not more than 15 mu m to obtain the colored electrophoretic coating.

10. The method for preparing a colored electrodeposition paint according to claim 9, characterized in that: the modified pigment is prepared by the following steps: mixing a pigment and deionized water according to a mass ratio of 1:4-6 to obtain an aqueous suspension, heating to 55-65 ℃, adding 1.5-2.5 mass% of polycarboxylate calculated by the pigment, heating to 75-80 ℃, stirring at a high speed for 30-60min, filtering, and drying to obtain the pigment.

Technical Field

The invention belongs to the technical field of electrophoretic coatings, and particularly relates to a colored electrophoretic coating and a preparation method thereof.

Background

The electrophoretic coating is a novel coating with low pollution, energy conservation, resource conservation and good corrosion resistance, has the advantages of smooth coating and good water resistance and chemical resistance, is easy to realize mechanization and automation of the coating industry, is suitable for coating workpieces with edges, corners and holes, and is widely applied to various fields, such as automobiles, electromechanics, household appliances, medical appliances and other industries requiring electrophoresis. However, the existing electrophoretic coating has the following disadvantages: the coating has the problems of easy sedimentation and easy precipitation, and the problems of uneven paint film thickness, unsatisfactory weather resistance and the like after coating.

In recent years, the electrophoretic coating materials are developed toward ultraviolet-curable type, thick-film type, low-temperature-curable type, edge-and-corner-anticorrosive type, and weather-resistant type. However, the color tone of the electrophoretic paint is often relatively single, and the electrophoretic paint hardly has the same multi-color as other paints. In order to meet the market demand of color diversification, painting users usually use toner to adjust the color required by customers. Thus, the development of the color of the electrodeposition paint is hindered by the large pigment particles, which affect the painting effect, the lack of surface treatment of the pigment, the instability of the paint liquid, the ineffective control of the color difference of the paint film, and the like.

Chinese patent CN109082173A discloses a water-based paint which is wet-on-wet with a wet electrophoretic paint, which comprises acrylic resin, a defoaming agent, a dispersant, pigment fillers, a solvent, amino resin, a leveling agent and deionized water, and integrates the salt spray resistance of the electrophoretic paint, and also ensures the weather resistance of acrylic acid, but the pigment fillers are not directly added through any surface treatment or modification, and have poor compatibility and low affinity with the paint system, and after the paint is placed for a long time, the pigment is easy to deposit, which causes the instability of paint liquid and the rough surface of the paint film prepared from the paint liquid.

Disclosure of Invention

The invention aims to provide a colored electrophoretic paint and a preparation method thereof, and the colored electrophoretic paint has the characteristics of good coloring effect and excellent weather resistance.

The technical scheme adopted by the invention for solving the problems is as follows: the colored electrophoretic paint comprises the following components in parts by mass:

25-35 parts of acrylic resin

15-30 parts of amino resin

0.6-5 parts of pigment

1-2 parts of zirconium phosphate

1.5-3.5 parts of neutralizing agent

0.3-1 part of organic solvent

30-50 parts of deionized water

Wherein the pigment is polycarboxylate modified pigment, and the average particle size of the zirconium phosphate is 50-150 nm.

Preferably, the average particle size of the zirconium phosphate is 100 nm.

Preferably, the acrylic resin is a hydroxy acrylic resin.

Preferably, the amino resin comprises methylated melamine resin and butylated melamine resin, and the mass ratio of the methylated melamine resin to the butylated melamine resin is 1-2: 1-3.

Preferably, the average particle size of the pigment is 10 to 15 nm.

Preferably, the polycarboxylate is obtained by copolymerization of a comonomer under the action of an initiator and under a stirring condition, wherein the comonomer is methacrylic acid and sodium allylsulfonate, and the molar ratio of the methacrylic acid to the sodium allylsulfonate is 3-5: 0.5 to 1; the copolymerization reaction temperature is 70-90 ℃, and the time is 2.5-3.5 h; and after the polymerization reaction is finished, adding sodium hydroxide into the copolymerization product for neutralization, and adjusting the pH value to 6-7.

More preferably, the molar ratio of methacrylic acid to sodium allylsulfonate is 3.3: 1.

preferably, the neutralizing agent is one or more of N-methyldiethanolamine, N' -dimethylethanolamine and triethylamine.

Preferably, the solvent is one or more of isopropanol, ethylene glycol ethyl ether and n-butyl ether.

The invention also aims to provide a preparation method of the colored electrophoretic paint, which comprises the following steps:

(1) fully mixing acrylic resin, pigment and zirconium phosphate, and uniformly stirring in a sand mill dispersing machine.

(2) Adding a neutralizer into the step (1), uniformly stirring, adding an amino resin, and stirring at a high speed.

(3) And finally, sequentially adding an organic solvent and deionized water, uniformly stirring and grinding until the fineness of the coating is not more than 15 mu m to obtain the colored electrophoretic coating.

Preferably, the pigment is prepared by: mixing a pigment and deionized water according to a mass ratio of 1:4-6 to obtain an aqueous suspension, heating to 55-65 ℃, adding 1.5-2.5 mass% of polycarboxylate calculated by the pigment, heating to 75-80 ℃, stirring at a high speed for 30-60min, filtering, and drying to obtain the pigment.

Compared with the prior art, the invention has the advantages that:

(1) the nano zirconium phosphate adopted by the invention has stable structure, high mechanical strength and strong acid and alkali resistance, and can effectively prevent small molecule corrosive medium and oxidizing substance from invading when being added into an electrophoretic coating, thereby greatly improving the weather resistance; meanwhile, the nano zirconium phosphate can improve the dispersion stability of the pigment and prevent agglomeration, the particle size of the zirconium phosphate is 50-150nm, preferably 100nm, and the dispersion effect is better; in addition, the nano-grade zirconium phosphate is compounded with acrylic resin and amino resin to form inorganic particles/resin, so that the net structure is firmer and has good stability.

(2) The pigment is modified by polycarboxylate, and the introduction of the polycarboxylate containing a large number of carboxyl and sulfonic groups can form charges on the surface of the pigment, improve the dispersion of the pigment through charge repulsion and prevent flocculation.

(3) According to the invention, the hydroxyl acrylic resin is matched with the methylated melamine resin and the butylated melamine resin, and the three are crosslinked with each other, so that the firmness of a formed film is greatly improved; the three main resins are good in compatibility with the modified pigment and zirconium phosphate, the pigment is not easy to settle and separate out, the prepared electrophoretic paint is good in stability, and the defects of color difference and rough paint film surface are avoided.

Detailed Description

The present invention will be described in further detail with reference to examples.

Example 1

The colored electrophoretic paint comprises the following components in parts by mass:

30 parts of hydroxy acrylic resin

10 parts of methylated melamine resin

Butyl etherified melamine resin 10 parts

Polycarboxylate modified pigment 1.5 parts

1.5 parts of zirconium phosphate

2 parts of N-methyldiethanolamine

0.5 part of isopropanol

50 portions of deionized water

The average particle size of zirconium phosphate is 100nm, the average particle size of polycarboxylate modified pigment is 10nm, the polycarboxylate is obtained by carrying out copolymerization reaction on a comonomer at 80 ℃ by using sodium hypophosphite as a chain transfer agent under the action of an initiator ammonium persulfate, reacting for 3 hours, and then adding sodium hydroxide to adjust the pH to 6-7, wherein the comonomer is methacrylic acid and sodium allylsulfonate, and the molar ratio of the methacrylic acid to the sodium allylsulfonate is 3.3: 1.

a preparation method of a colored electrophoretic paint comprises the following steps:

(1) the hydroxy acrylic resin, the polycarboxylate modified pigment and the zirconium phosphate are fully mixed and evenly stirred in a sanding disperser.

(2) And (2) adding N-methyldiethanolamine into the step (1), uniformly stirring, and then adding amino resin, and stirring at a high speed for 30 min.

(3) And finally, sequentially adding isopropanol and deionized water, uniformly stirring and grinding until the fineness of the coating is not more than 15 mu m to obtain the colored electrophoretic coating.

Wherein, the preparation of the modified pigment in the step (1) comprises the following steps: mixing the pigment and deionized water according to the mass ratio of 1:5 to obtain an aqueous suspension, heating to 60 ℃, adding 1.5 mass percent of polycarboxylate calculated by the pigment, heating to 80 ℃, stirring at a high speed for 30min, filtering and drying to obtain the pigment-based ink.

Example 2

The colored electrophoretic paint comprises the following components in parts by mass:

26 parts of hydroxyl acrylic resin

12 parts of methylated melamine resin

Butyl etherified melamine resin 12 parts

Polycarboxylate modified pigment 2 parts

2 parts of zirconium phosphate

Triethylamine 1.5 parts

Ethylene glycol Ether 0.3 parts

45 parts of deionized water

The average particle size of zirconium phosphate is 100nm, the average particle size of polycarboxylate modified pigment is 15nm, the polycarboxylate is obtained by carrying out copolymerization reaction on a comonomer at 75 ℃ by using sodium hypophosphite as a chain transfer agent under the action of an initiator ammonium persulfate, reacting for 3.5 hours, and then adding sodium hydroxide to adjust the pH to 6-7, wherein the comonomer is methacrylic acid and sodium allylsulfonate, and the molar ratio of the methacrylic acid to the sodium allylsulfonate is 3.3: 1.

a preparation method of a colored electrophoretic paint comprises the following steps:

(1) the hydroxy acrylic resin, the polycarboxylate modified pigment and the zirconium phosphate are fully mixed and evenly stirred in a sanding disperser.

(2) And (2) adding triethylamine into the step (1), uniformly stirring, then adding methylated melamine resin and butylated melamine resin, and stirring at a high speed for 30 min.

(3) And finally, sequentially adding ethylene glycol ethyl ether and deionized water, uniformly stirring and grinding until the fineness of the coating is not more than 15 mu m to obtain the colored electrophoretic coating.

Wherein, the preparation of the modified pigment in the step (1) comprises the following steps: mixing the pigment and deionized water according to the mass ratio of 1:4 to obtain an aqueous suspension, heating to 55 ℃, adding 2 mass percent of polycarboxylate calculated by the pigment, heating to 75 ℃, stirring at a high speed for 30min, filtering and drying to obtain the pigment-based ink.

Comparative example 1

The only difference from example 1 is: the pigment is not modified and is a common pigment.

Comparative example 2

The only difference from example 1 is: no zirconium phosphate was added.

Comparative example 3

The only difference from example 1 is: the particle size of the zirconium phosphate is 300 nm.

Comparative example 4

The only difference from example 1 is: in the absence of methylated melamine resin.

The electrodeposition coatings obtained in examples and comparative examples were subjected to conventional electrodeposition coating methods to prepare coating films, and the results of the tests are shown in Table 1 below.

Detection method

(1) Precipitability of electrodeposition coating

A250 ml stoppered measuring cylinder (bottom should be flat, other suitable container can be used) is filled with 22cm of the working solution, the cover is closed, and after standing for 24h at (23 + -2) deg.C, the height of the sediment at the bottom is measured in mm. The judgment standard is as follows: 4 is very good, the sedimentation height <1 mm; 3 is better, the sedimentation height is more than or equal to 1mm and less than 2 mm; 2 is a difference, and the precipitation height is more than or equal to 2mm and less than 3 mm; 1 is very poor and the sediment height is more than or equal to 3 mm.

(2) Paint film appearance

And observing whether the orange peel is smooth or uneven or flat by naked eyes. The judgment standard is as follows: 4 is very good, 3 is good, 2 is bad, and 1 is very bad.

(3) Washability of paint film

Detection is carried out according to the standard of GB/T9266-2009. The judgment standard is as follows: 4 is very good, and the washing and brushing resistance is more than or equal to 1 ten thousand times; 3 is good, and the washing resistance is more than or equal to 8 thousand and less than 1 ten thousand; 2 is a difference, and the washing resistance is more than or equal to 6 thousand and less than 8 thousand; 1 is very poor and the scrub resistance is less than 6 thousand.

(4) Weather resistance of paint film (in 1500 h)

The test was carried out in accordance with GB/T1865-1997, and the discoloration (color difference) of the paint film was examined. The judgment standard is as follows: 4 is very good, with a colour difference value < 3.0; 3 is good, the color difference value is more than or equal to 3.0 and less than 6.0; 2 is difference, and the color difference value is more than or equal to 6.0 and less than 9.0; 1 is very poor, and the color difference value is more than or equal to 9.0.

Table 1 table of performance test results

In addition to the above embodiments, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of the claims of the present invention.