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Electro-Deposition
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Electro-Deposition

As a process to extract film of paint on the surface of the metal products (material ) hung on the positive & negative poles through uniting dyes of the various colors with metal ion using the electric-chemical property, it creates new higher value-added products through realizing high-class color.

Principle & instrument of Electro-Deposition coating

As for electro-deposition coating, paints comes to be attached to the surface of material with the phenomenon like following below if direct current passes between the material deposited to the positive or negative pole and its opposite poles in the electro-deposition paint solution.

(Electrolysis) If direct current passes to electrolyte solution, the chemical decomposition happens through discharge from the positive & negative pole respectively, and this phenomenon is called Electrolysis. In case of electro-deposition, this Electrolysis also happens, and emits ion from the positive & negative pole.

(Electro-Phoresis) If an electric field is given to the particles separated as the state of colloid in the electrolyte solution, it’s the phenomenon to move toward a pole having the opposite electric charge because of having electric charge by dissociation of dispersion solute & absorption of ion. Resin particle is salt having much carboxyl group & neutralized into organic amine, so it’s dissociated in the water.

(Electro-deposition) It’s the phenomenon for the particles moving to the positive & negative poles to be extracted as a state of a molecule after mutual reacting.

(Electro-Osmosis) Dehydration happens through extracting of paint film on the metal surface of material and operating of paint film with the porous plate.

In other words, setting time after electro-deposition isn’t necessary after moisture left in film of paint passes through film of paint by electric penetration during applying an electric current and emits into solution. Like above, among 4 phenomenon, Electrolysis & Electro-Phoresis have relations to moving of paint particles happened around poles, and Electro-deposition & Electro-Osmosis have relations to attaching to the surface of material.

Comparative table of Electro-deposition coating

Anion Cation
Resin Polycarboxyl Resin
(Many carboxyl radicals(-COOH) among resin)
Polyamine Resin
(Many Amine radicals among resin)
Counteractive Base like Amine& KOH-COOH + A →
-COO- + A+ (for water insoluble) (Counteractive)
(for water insoluble)
Organic & mineral acid + AH → + A-()
(for water soluble)
Coating method At material(Positive)
① OH- → 1/2 ↑ + H+ (Electrolysis) (Acid)
② -COO- + H+ → - COOH (insoluble extraction)
③ Me → + + Ne- (Material) (Metal elution)
④ N-COO- + + → (Extraction) At material (Negative)
① H+ + → ↑ + OH- (Electrolysis)(Alkali)
② + + OH- → + (insoluble extraction)
※ No elution of material

Make-up Composition & Range of Electro-Deposition Coating

Item Electro-Deposition Coating Remark
Basic composition water 90 wt% Management of paint(dyes)is important, Conductivity control
Pigment(resin+dye) 10 wt%
Leveling agent 0.1~1 wt% Precise amount(small)
Antifoaming agent Precise amount(small)
Antifoaming agent Precise amount(small)
Antifoaming agent 0.1~1 wt%
pH 3.6~4
Viscosity 6~7
Voltage 27V Voltage adjustment method
Electro-deposition speed 40secs
Solution temp 25~30(27)℃
Filtration STIRRER agitation
Whole processing No organic matters/ rust preventive oil/foreign matters Adhesion inferiority of electro-deposition coating-primary cause
Drying temp 150~180(170) ℃*30min

Main flow chart of Electro-Deposition Coating(CSP)

Applications

Cell phone/camera/ Exterior Mp3 cases, Mobile electroforming camera/ Key button decorations, Name plate, key ring. Electro-deposition materials for lower extremity, other accessories for decoration, RoHS substitute, products of high-solidity.