JPS5831217B2 - Aeon Kokanjiyushino Shiyorihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating a cation exchange resin, and in particular, to recovering and reusing a concentrated paint from a cation exchange resin that has adsorbed a concentrated paint mainly composed of a neutralized product of a resin containing acidic groups. With,
The present invention relates to a method for treating an ion exchange resin, which comprises regenerating a washed cation exchange resin.

In recent years, methods using water-based paints have attracted attention for their advantages over conventional methods using organic solvent-based paints for the purpose of preventing pollution problems or streamlining the painting process.

However, the water-based paints that have been developed to date contain highly polar low-molecular substances contained in the resin that makes up the paint. The above-mentioned highly polar low-molecular compounds are eluted into the aqueous medium over time from the paint particles constituting the paint bath, creating a stable dispersion equilibrium of the paint particles in the aqueous medium.
The dispersion stability of paint particles was impaired.

In addition, when water-based paints are made by neutralizing resins with acidic groups such as those mentioned above, especially in dip coating using a water-based paint bath or electrodeposition coating, there may be The amount of base contained in the paint does not match the amount of base contained in the replenishment paint, and the amount of base that is always carried out as a coating film from the water-based paint bath is always smaller. Water-based paint baths should not be used because excessive bases tend to accumulate in paint baths and deteriorate the properties of the water-based paint bath or the properties of the coatings of coated articles painted using such water-based paint baths. A method has been developed in which the base concentration in the aqueous coating bath is kept constant by constantly treating the base with a cation exchange resin, but such a method inevitably requires complicated operations.

Therefore, the present inventors investigated a method for producing water-based paints that does not require such complicated operations, and treated a resin having an acid group or its neutralized product with an anion exchange resin, and then neutralized it if necessary. After adding the agent, we have established a technology for further treating this resin with a cation exchange resin, and have previously applied for a patent.

The problem with this S is that when a neutralized product of an acidic group-containing resin is treated with a cation exchange resin and the cation exchange resin is further regenerated, the concentrated paint adsorbed on the cation exchange resin This is the handling of

This can be easily removed by washing with water using normal methods, but if this washing water is used directly as waste water, the waste water itself becomes a cause of pollution and becomes a major social problem. Rather, if the concentrated paint adsorbed on the cation exchange resin is itself used as a paint, it can be used without any problems, and the problem lies in how well this concentrated paint can be recovered.

In order to solve the above problems, the present inventors investigated an efficient method for recovering this thick paint, and completed the present invention.

The gist of the present invention is to use a cation exchange resin that has adsorbed a neutralized product of an acid group-containing resin, deionized water, and a resin that has been treated with a cation exchange resin that has adsorbed a neutralized product of the acid group-containing resin. A water-based paint bath made, or waste liquid from washing with deionized water of painted products electrodeposited using this water-based paint bath, or water obtained by passing these through an ultra-ultrafilter or a reverse osmosis filter. or use this washing water as a dilution solvent when diluting the neutralized product of the acidic group-containing resin to form an aqueous paint bath. A method for treating a cation exchange resin, which is characterized in that the finished cation exchange resin is further washed with water if necessary, and then regenerated.

According to the method of the present invention, unlike conventional methods, tap water or industrial water is not used when removing paint from a cation exchange resin that has adsorbed concentrated paint, so the recovered paint-containing water is directly transferred to the aqueous paint bath. Even if the recovered water is recovered or used as part of the paint dilution solvent to make an aqueous paint bath, it does not contain any obscene ions that would reduce the bath stability of the paint. Compared to the stability of water-based paint baths made using ionized water, it is possible to create a water-based paint bath that does not cause color loss.

Furthermore, the cationic resin to be treated can also very efficiently prevent the adsorption of obscene ions from the outside, making this an extremely convenient method.

The method of the present invention exhibits its effects most efficiently because:
Acidic group-containing resin or its neutralized product is treated with an anion exchange resin to remove highly polar acidic substances contained in the acidic group-containing resin, especially unpolymerized monomers exhibiting acidity, or their reduced Polymerization products, polymerization catalysts, decomposition products of stabilizers such as hydroquinone contained in the monomers used, etc. may reduce the dispersion stability of paints in aqueous media, and coatings formed from these water-based paints may Applicable to the treatment of cationic disguised resins that have adsorbed neutralized products of acidic group-containing resins from which substances that reduce the heat reflow properties during heat curing of films and reduce the corrosion resistance and water resistance of the resulting coating films are removed. According to the method of the present invention, the cation exchange resin that has adsorbed concentrated paint can be treated in a closed cycle, so there is no problem of pollution caused by wastewater, and the recovered paint can be used effectively. The big advantage is that you can.

Example In a flask equipped with a stirrer, a reflux condenser and a thermometer, 39.9 parts of 2-ethylhexyl acrylate, 25.8 parts of styrene, and 1 part of N-butoxymethylacrylamide were added.
9.1 parts, itaconic acid 3.23 parts, azobisisobutyronitrile 2.93 parts, 2-mercaptoethanol 1.1
2 parts and 62.5 parts of isopropyl alcohol were charged, the temperature was raised to 70'C over 2 hours and 30 minutes, and then polymerization was continued at 70C for 5 hours and 30 minutes.

Thereafter, the temperature was raised to 75°C and the temperature was maintained for 4 hours to complete the polymerization.

The resin was neutralized by adding β-dimethylamine ethanol in an amount corresponding to 45% of the total carboxyl groups to the acidic resin solution obtained as described above.

To 100 parts of this neutralized resin solution, 75 parts of titanium oxide (JR-600E, manufactured by Teikoku Kaisha Ltd.) was added, thoroughly kneaded in a ball mill, and then 200 parts of the above neutralized resin solution was added to prepare a white enamel paste.

After adding 5 g of deionized water (Bi' to 1 ky of white enamel paste) and 5 g of 200 mesh OH type anion exchange resin (Diaion 5A-2OA manufactured by Mitsubishi Chemical Corporation) and stirring well, The ion exchange resin is removed by a filter and white enamel paste is created.■
made.

A white enamel paste O was prepared by passing the white enamel paste (1) through a column packed with an H-type strong acid type cation exchange resin (Diaion WK-10 manufactured by Mitsubishi Chemical Industries, Ltd.).

The white enamel paste KCII that had adsorbed the cation exchange resin in this way was washed with deionized water and used as a cleaning solution CI'), and the white enamel paste 0 was adjusted to have a solid content concentration of about 15% by weight. The cleaning liquid mark is obtained by washing the electrodeposition coating bath with water obtained by passing it through an ultra-ultrafilter, and further washing the painted product electrodeposited using the above electrodeposition coating bath with deionized water. What was washed with water was used as a washing liquid (9).

Furthermore, the washing water used to wash the ion exchange resin packed tower with the electrodeposition coating bath was designated as washing water (2).

In addition, the white enamel paste (Al) was passed through a cation exchange resin packed tower similar to that used in the above method, and then the cation exchange resin packed tower was washed with deionized water, and the recovered liquid was used as a cleaning solution.

The washing water (7) obtained as described above was concentrated or added with white enamel paste (2) to a solid content of about 15% by weight to prepare an electrodeposition coating bath, and the white enamel paste (IC) was added with deionized water. An electrodeposition coating bath was prepared by adjusting the solid content concentration to 15% by weight.

Using the electrodeposition coating bath prepared as described above, using a zinc phosphate treated plate as the object to be coated, voltage 120v1 electrodeposition time 2
The properties of the coating film formed by washing the obtained coated product with water and baking it at 180° C. for 30 minutes, as well as the properties of each electrodeposition coating bath, are shown in the following table.

As is clear from the results in the table above, it can be seen that the paint recovered by the method of the present invention can be used in white enamel paste circles without color loss.

In addition, after washing the ion exchange resin, the adsorbed resin content was completely removed, so the regeneration process was extremely easy.

Claims (1)

[Claims] 1. A water-based paint bath made by using a cation exchange resin with a particle size of 1200μ or less that has adsorbed a neutralized product of an acid group-containing resin, deionized water, and a neutralized product of the acid group-containing resin, or this water-based paint bath. washing wastewater with deionized water of a coated product that has been electrodeposited using the method, or washing the water-based paint bath or washing wastewater with water obtained by passing it through a super extraocular filtration device or a reverse osmosis filter, This washing water is returned to the aqueous paint bath or used as a diluting solvent when diluting the neutralized product of the acidic group-containing resin to form an aqueous paint bath, and the cation exchange resin after the washing process is recycled. 1. A method for treating a cation exchange resin, the method comprising: treating a cation exchange resin;