Unlock instant, AI-driven research and patent intelligence for your innovation.

Lead-free cationic electrodeposition coating composition, and electrodeposition coating process

a technology of cationic electrodeposition and coating composition, which is applied in the direction of electrolytic coatings, coatings, paints for electrolytic applications, etc., can solve the problems of difficult to sufficiently increase the deposition property of binder resin, difficult to deposit coating solids on the substrate, etc., and achieve high throwing power, reduce and increase film resistance of coated films

Inactive Publication Date: 2008-10-23
KOJIMA YOSHIO +2
View PDF8 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012]Another factor seems to be that ionic components contained in the coating composition such as an ionic group and a hydrophilic functional group remains in the coated film formed from the coating composition, the ionic components works as a charge transporting medium, and thereby film resistance of the coated film is reduced. Thus, in order to achieve high throwing power in an electrodeposition coating, film resistance of the coated film have to be raised by removing the factors like these.
[0013]The present invention solves the problems of the background art, and it is an object of the present invention to provide a lead-free cationic electrodeposition coating composition which has high throwing power, and exert a little influence on the environment due to its low VOC, low metal ion content, and reduced consumption of a coating composition itself. It is another object to provide a electrodeposition coating process which can form an electrodeposition coated film having even thickness over the whole portions of a substrate to be coated with using the lead-free cationic electrodeposition coating composition.

Problems solved by technology

Because a voltage applied to an uncoated portion of the substrate is weak, a coating solid is difficult to deposit on the substrate.
For example, a conventional electrodeposition coating composition has relatively low nonvolatile content, for example 20% by weight, and it has been difficult to sufficiently increase deposition property of the binder resin.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

example a

Preparation Example A1

Preparation of Amine-Modified Epoxy Resin

[0079]92 parts of 2,4- / 2,6-tolylenediisocyanate (weight ratio=8 / 2), 95 parts of methyl isobutyl ketone (hereinafter, referred to as MIBK) and 0.5 part of dibutyltin dilaurate were loaded to a flask equipped with a stirrer, a cooling tube, a nitrogen introducing tube, a thermometer and a dropping funnel. 21 parts of methanol was added while stirring the mixture.

[0080]Starting at room temperature, the reaction mixture was allowed to rise to 60° C. by exothermic, the reaction was retained for 30 minutes, and 57 parts of ethylene glycol mono-2-ethylhexyl ether was dropped from the dropping funnel. Furthermore, 42 parts of bisphenol A-propylene oxide 5 mol adduct was added. The reaction was carried out mainly in the temperature range of 60 to 65° C., and continued until absorption based on an isocyanate group disappeared in IR spectrum measurement.

[0081]Next, 365 parts of bisphenol A type epoxy resin of epoxy equivalent 188 s...

preparation example a2

Preparation of Amine-Modified Epoxy Resin

[0083]An amine-modified epoxy resin having a glass transition temperature of 15° C. (solid content: 80%, number average molecular weight: 1640) was prepared according to the same manner as described in Preparation example A1 except that 74 parts of bisphenol A and 17 parts of octylic acid was employed.

preparation example a3

Preparation of Amine-Modified Epoxy Resin

[0084]An amine-modified epoxy resin having a glass transition temperature of 22° C. (solid content: 80%, number average molecular weight: 1810) was prepared according to the same manner as described in Preparation example A1 except that 87 parts of bisphenol A and no octylic acid was employed.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
thicknessaaaaaaaaaa
Tgaaaaaaaaaa
Login to View More

Abstract

The present invention provides a lead-free cationic electrodeposition coating composition which contains an aqueous medium, a binder resin composed of a cationic epoxy resin and a blocked isocyanate curing agent dispersed or dissolved in the aqueous medium, a neutralizing acid in order to neutralize the cationic epoxy resin, an organic solvent, and a metal catalyst, wherein the electrodeposition coating composition has a volatile organic content of 1% by weight or less, a metal ion content of 500 ppm or less, a neutralizing acid amount of 10 to 30 mg equivalent based on 100 g of binder resin solid content. The lead-free cationic electrodeposition coating composition has high throwing power, and exert a little influence on the environment due to its low VOC, low metal ion content, and reduced consumption of a coating composition itself.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a lead-free cationic electrodeposition coating composition, more specifically, a lead-free cationic electrodeposition coating composition having low volatile organic content, low metal ion content and high throwing power. Further the present invention relates to an electrodeposition coating process which is conducted with using the lead-free cationic electrodeposition coating composition.BACKGROUND OF THE INVENTION[0002]According to an electrodeposition coating method, a coated film can be formed even on narrow portions of a substrate to be coated having intricate shape, automatically and continuously. Therefore, the electrodeposition coating method is widely used for primer-coating a substrate having intricate shape and being required to have high rust resistance, such as an automobile body.[0003]Further, an electrodeposition coating method is superior in utilization efficiency of a coating composition to the other coatin...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): C25D9/00C08K9/04C09D5/44
CPCC08K9/04C09D5/44
Inventor KOJIMA, YOSHIOYAMADA, MITSUOUCHIDOI, SATORU
Owner KOJIMA YOSHIO