Guangzhou Youda Launches Anode Electrophoretic Paint with Good Leveling and High Solid Content

Guangzhou Youda has good leveling, high solid content, high light, high transparency, water-based anode acrylic electrophoretic paint

Electrophoretic paint, also called electrophoretic paint, many people still use the term "electrophoretic paint" instead of "electrophoretic paint". As the defects of conventional spraying continue to emerge, electrophoresis has become more and more popular. The electrophoretic paint has also been continuously updated, from anodic electrophoretic paint to cathodic electrophoretic paint, from single-component electrophoretic paint to two-component electrophoretic paint. The development of electrophoretic paint has also promoted the development of electrophoretic coating, making more products no longer Use spray technology instead of electrophoresis. Therefore, Guangzhou Youda has good leveling, high solid content, high gloss, high transparency, and water-based anode acrylic electrophoretic paint. It uses imported raw materials and has good stability..

 

I. Introduction to Anion Electrocoating (Acrylic)

The polymer of the acrylic resin is introduced into a functional group having a carboxyl (-COOH) type, so that it can generate a high molecular salt with an organic or inorganic base and dissolve in water. Under the action of DC voltage, the salt is broken down, the acrylic resin with anions moves to the anode coating, is neutralized by hydrogen ions and deposits on the coating, and is cured by baking to produce a crosslinking reaction. .

As the electronic painting has the advantages that traditional oil-based baking paint does not have, electronic painting has been widely valued. Its main advantages are as follows:

1. High painting efficiency: During the painting operation, the loss of paint liquid is extremely small, and the painting efficiency can reach more than 95%.

2. Suitable for automation, consistent operation and production, minimal manpower required.

3. Can be coated with any shape of the object, not subject to unevenness, good adhesion, excellent uniformity (throwing power)

4. The thickness of the coating film is uniform and the adhesion is excellent, so the corrosion resistance is good.

5. Use water as solvent, less pollution, low pollution, not easy to burn.

6. Project specificity: wet coating, continuity.

The main disadvantages are as follows:

(1) Limitation of film thickness: It is possible to obtain a film with a thickness of 25 to 30 μ.

(2) The degree of change in the color of the coating film is not large: the electric paint tank is generally large.

(3) The cost of hardware equipment is more expensive.

(4) is limited to the coating of conductive substrates.

 

Composition of Electronic Coatings

基本 The coatings used for anion books are as follows:

(1) skeleton resin: a linear polymer having a carboxyl group (-COOH).

(2) Neutralizing agent: Organic or inorganic alkali compounds which can be neutralized with carboxylic acid.

(3) Hardener: A chemical that can be bridged by its own functional groups and specific functional groups of the backbone polymer.

(4) Solvent: Auxiliary to help the stability of the polymerization reaction and meet the solubilization and improve the properties of the paint film

(5) Others: such as pigments, leveling aids, antioxidants.

 

Third, pre-treatment project

For the coating process of aluminum building materials, it is widely used in the industry as shown in Table 1.

Table 1: Pre-treatment project of aluminum building materials

A

Anodizing operation 1. Hanging the stent

 2. Dehydration water Immersion in the aqueous solution of organic solvents and surfactants

 3.Washing and washing

 4. Alkaline corrosion Etching in alkali or saline solution

 5.Water rinsing, industrial water immersed in overflow

 6.Zhonghehe immersed in acidic aqueous solution

 7.Water rinsing, industrial water immersed in overflow

 8. Anodizing Applying electricity in sulfuric acid solution, the surface of aluminum is oxidized

 9.Washing and washing

 10. Electrolytic discoloration: AC electrolysis in aqueous metal solution, metal precipitation

 11.Water washing and dipping in overflowing industrial water

B

Electrode coating operation 12. Hot water washing, dipping in heated deionized water

 13.Water rinsing, dipping in deionized water

 14. Electrodeposition Immersion in electrocoating coating liquid, energization, precipitation of coating film

 15. Rinse with water, dip in the RO (reverse osmosis device) of the electrolyzing solution, and dialyze out

 16.Remove the water

 17. Roasting simmered in the hot air oven, the coating resin is bridged and hardened

 18, unloading the material to be removed from the rack

 

Project management

Although the surface coating cost of aluminum building materials only accounts for a small part of the cost of building materials, the quality of the coating film affects the appearance and quality of the product. Therefore, each condition in the electronic writing project must be strictly managed to ensure the quality. Uniform.

5.1 Management of electric paint fluid

The composition and properties of the electric paint liquid have a great impact on the quality of the coating film, and the management reasons in each project are as follows:

(1) Liquid temperature: When the liquid temperature of the electric paint liquid is too high, the electric conductivity of the paint liquid will increase. At the same voltage and time, the film thickness will increase, and the uniformity of the coating film will decrease.

(2) Solid content: Although high solid content contributes to the increase in electrical conductivity, film thickness and good uniformity, it causes the paint liquid to be carried out due to the increase in viscosity, while at low solid content, the film thickness will reduce.

(3) PH value: The PH value is the most direct indicator of the degree of neutralization of electric paint resin. The PH value will increase with the increase of working hours and hours. When the pH value exceeds the allowable range, the film thickness will decrease significantly. The uniformity of the coating film is also reduced, leading to the occurrence of re-solubility of the film; but if the pH value is adjusted too low, the stability of the coating film is reduced, and precipitation is easy to occur, and the coating film will deposit gel and agglomerate. Ion exchange is an indispensable management item to control the pH in a suitable range.

(4) Electrical conductivity: Basically, the electrical conductivity is synchronized with the pH value, but during the pretreatment process, once the generated ions are brought into the electrical paint tank, the electrical conductivity of the paint solution will rise abnormally.

(5) Acid value: Under the same solid content, the acid value varies depending on the composition of the paint solution. If the possibility of anion pollution is ruled out, the acid value of acrylic resin and melamine resin content is too high or too low will cause Poor film quality.

(6) Amine value: The increase of amine value is directly related to pH and conductivity. If the amine value is too high, the pH value will increase with the increase of conductivity, so it must be reduced by cation exchange.

(7) Melamine resin amount: Each acrylic electric paint resin has its best melamine resin content. Too high or too low will cause poor film quality.

(8) Solvent: In addition to the consideration of resin synthesis, the role of the solvent has a direct impact on the film thickness and quality of the coating film, and the solvent also helps the resin disperse in water.

(9) Sulfate ions: The acid tank and coloring tank in the pre-treatment of aluminum building materials contain high concentration of sulfate ions. If the water is not washed well, it will be easily brought into the electric paint solution, which will cause great adverse effects. Anion exchange to prevent accumulation.

(10) Precautions for the exchange treatment of electric paint liquid

a. After the anion resin is regenerated with NaOH, it must be cleaned with pure water to a pH below 9.5 before the ion exchange step of the electric paint liquid can be carried out to avoid the residual NaOH being brought into the electric paint liquid and affecting the occurrence of poor coating film. .

b. After the cationic resin is regenerated by HCl, it must be pressure-cleaned with pure water to pH 6.0 or higher before the ion exchange step of the electric paint liquid can be carried out to avoid the residual HCl being brought into the electric paint liquid and affecting the poor coating film.

5.2 Management of pre-treatment project

(1) Cleaning of inorganic ions:

For example, SO–, Al3 + ... plasmas are stored in the film generation tank and the color development tank with extremely high humidity. Therefore, they must be washed with water for many times before writing. Generally, the water washing steps before writing are as follows: Wash with overflowing industrial water, wash with heated deionized water, spit out acid (the other purpose is to seal the holes), and finally use deionized water for the final washing.

(2) Filtration and isolation of impurities in the air

If there are excessive impurities in the air of the coating factory, the coating film will have craters and irritable stains. These impurities, such as dust in the air, must be removed by an air purification system. In addition to the dust, there is an alkali tank. The generated alkali mist, these mist particles will not only cause the shortcomings of the coating film, but also fall into the electroplating tank to condense the agglomeration of the paint solution and the deterioration of the appearance of the coating film, so the electroplating tank must be isolated from the pretreatment.

5.3 Management of deionized water

The pure water used in the electronic writing factory must be deionized water. In particular, the pure water used for diluting the resin must have a conductivity of less than 5 μS㎝– or less.

 

ED–9

1. Specification of ED-9 resin

Item Product Specifications Inspection Conditions

View of nephew

Solid content 60 ± 2% 180 ℃ × 1hrs

Viscosity Y ～ Z2 Gardner at 25 ℃

Chromatin ＜ 2 Grander

 

Second, ED-9 coating liquid use specifications

Items Scope of Application

Outer view milky white eyes contempt

Solid content 6.0 ± 0.5% 105 ℃ × 3hrs

Liquid temperature 20 ～ 25 ℃

PH 7.4 ～ 8.0 6% solid content

Conductivity 800 ～ 1100 6% solid content

Electrical voltage 90 ～ 130V 6%, 120 seconds, 22 ℃

Time 90 ～ 120 seconds 22 ℃, NV 6%

Anion exchange good IRA 400

Cation exchange without precipitation IRC 84 or Imacz-5

 

Three, ED-9

Item Performance test conditions

Outer view, flat and flawless, visual inspection

Gloss (60 ° C) 8μ, brown color

Gloss (60 ℃) 8μ, natural color of aluminum

Hardness 3H ～ 4H Bake at 180 ℃, 30 minutes, Mitsubishi pencil

Adhesion 100∕100 square test

Alkali resistance No exception 0.5%, NaOH 20 +/– 1 ℃ for 24 hours

Acid resistance no abnormal 5% HCl 20 +/– 1 ℃ 24 hours

Weatherability 90% retention rate QUV weathering tester: 300 hours

Boiling water resistance No exception 95 ° C, boiling water 98 ° C 5 hours

Salt resistance no abnormal 5% NaCl × 35 ℃ × 200 hours