JPH0924333A - Method for recovering water base coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily recover an oversprayed coating material in a spray coating booth to be used when an article is coated and to recover the coating material as a reusable one as it is or after simple conditioning. SOLUTION: A collecting material with the surface temp. relative to a spray coating booth temp. cooled below the dew point temp. is set on this side of the filer for collecting the oversprayed water base coating material or wet dust collector in the spray coating booth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to collect easily oversprayed paint in a spray painting booth used for painting an article and collect it as a paint that can be reused as it is or by simple adjustment. The present invention relates to a method for recovering a water-based paint adapted for the purpose.

[0002]

2. Description of the Related Art Conventionally, for the purpose of preventing environmental pollution, a method for recovering oversprayed paint has been used when painting articles. The methods are roughly classified into dry type and wet type. The dry method is a method of collecting paint that has been oversprayed on a shroud, a filtration filter made of glass wool, non-woven fabric, paper, or the like. The wet method is a method of collecting the liquid mist such as water or oil, the curtain-shaped liquid flow, and the oversprayed paint on the recovery liquid tank.

[0003]

However, in the dry method, it is difficult to easily peel off and remove the overspray paint collected on the surrounding plate, the filtration filter made of glass wool, non-woven fabric, paper or the like. After being used for a certain period of time, it is general to discard the filtration filter and the overspray paint without reusing them, but there is an increase in running cost for the filter to be replaced and an environmental problem due to industrial waste generation.
In the wet type, liquid mist such as water or oil, curtain-shaped liquid flow, overspray paint collected in a recovery liquid tank, etc. is solid-liquid separated by using a chemical called a non-sticking agent to form a solid overcoat. Although it is common to dispose of spray paint, there are environmental problems due to the generation of industrial waste.
In the wet type, there is a method of concentrating the collected liquid that collects the overspray paint to regenerate and reuse the paint.
A recovery liquid treatment device was required for concentration and paint adjustment, and it was not easy to recover and reuse overspray paint. Under such circumstances, there is a demand for an invention of a recovery method as a paint that can be easily recovered as an oversprayed paint in a spray painting booth used when painting an article and can be reused as it is or with a simple adjustment. There is.

[0004]

In order to solve the above-mentioned problems, the inventors of the present invention have earnestly studied the method for recovering the paint, and as a result, before the filter or the wet dust collector for collecting the oversprayed paint. By installing a collection material whose surface relative temperature with respect to the spray coating booth temperature is cooled below the dew point temperature, the overspray paint adhering to the collection material flows down in the direction of gravity, and as a result, below the collection material. It was found that overspray paint can be recovered as a paint that can be reused as it is or with simple adjustment. Since water-based paint uses water, it is easily affected by humidity, and under high humidity, it may sag or may not dry. Due to the characteristics of this water-based paint, by cooling the relative temperature of the trapping material surface to the spray coating booth temperature below the dew point temperature, dew condensation occurs on the trapping material surface, and the overspray paint adhering to this trapping material surface is gravitated. It is thought to flow in the direction. Based on these findings, with the aim of recovering the oversprayed water-based paint easily as it is or as a paint that can be reused with simple adjustment in the spray painting booth used when painting articles The present invention has been completed by finding out an applicable water-based paint recovery method.

That is, according to the present invention, in a spray coating booth used for coating an article, a surface relative temperature to a spray coating booth temperature is set as a dew point temperature before a filter or a wet dust collector that collects oversprayed aqueous paint. The present invention relates to a method for recovering a water-based paint, which comprises installing a cooled trapping material.

The trapping material used in the present invention is most preferably installed in a spray painting booth, but it can be installed and used in other places when the article is painted. As the spray coating booth, a conventionally known dry type or wet type can be used. In this case, the trapping material needs to be installed behind or on the side of the coated article as viewed from the coating machine and before the filter or wet dust collector of the spray coating booth for collecting the coating material.

The trapping material used in the present invention has an arbitrary shape,
Although any size and any number can be used, it is preferable to install the column-shaped trapping material in the vertical direction, and it is most preferable to install several column-shaped trapping materials with a gap. Further, it is also possible to install the scavenger only on a portion where there is a large amount of oversprayed paint, and in this case, the trapping material can be fixed by an arbitrary support. If a plate-shaped trapping material is installed, or if a column-shaped trapping material is installed without leaving a gap, it interferes with the original dust collection capability of the spray coating booth, and as a result dust adheres to the coated article, It is not preferable because the smell of solvent may be muffled at the painting site.

The scavenger used in the present invention is iron, steel, cast iron, cast steel, stainless steel, and other iron, alloy material metals thereof, various plastics, composite materials thereof, or the like, on the surface of which dew condensation is possible. Materials can be used. Further, the surface of the collecting material can be subjected to various plating treatments or a water-repellent substance such as silicon or fluorine.

The trapping material used in the present invention is required to cool the relative temperature of the trapping material surface with respect to the spray coating booth temperature to a temperature below the dew point temperature. A method of cooling the collecting material through various liquids such as water or a refrigerant of various gases such as air, and a method of cooling through various heat conductors can be used.

The coating composition used in the present invention can be coated by a coating method such as air spray coating, airless spray coating, electrostatic coating or the like, but can also be coated by a shower coating, curtain flow coating or the like. .

The paint used in the present invention may be any water-based paint such as a water-soluble paint or a water-dispersed paint, and any paint containing water may be used. For example, there are alkyd resin paints, acrylic resin paints, polyester resin paints, vinyl resin paints, melamine resin paints, epoxy resin paints, urethane resin paints and the like.

In the present invention, the overspray paint adhering to the trapping material flows down in the direction of gravity, and the overspray paint is collected below the trapping material. It is also possible to collect the overspray paint on the side of the trapping material by installing, for example, below the trapping material. A collection tank can be installed to store the paint where the overspray paint flows down in the direction of gravity. The recovered paint can be reused as it is or after being adjusted. If adjustment is necessary, depending on the constituents of the overspray paint, for example, diluents such as water, neutralizing agents such as amines and acids, solvents such as alcohols, glycols and cellosolves, and other additions. Agents and the like can be added, mixed, filtered, and reused.

[0013]

Next, an embodiment of the present invention will be described. Example 1 A steel pipe having a length of 100 cm, a diameter of 0.8 cm, and a thickness of 0.1 cm was placed in front of a dry spray coating booth at an interval of 0.
We made a collection material that was fixed in the vertical direction with 63 pieces at 8 cm,
An overspray paint collection container was placed below the collector. Orion Machinery Co., Ltd. “Unit Cooler MOD
Water cooled to 10 ° C. with a cooler of “ELRKS-250S-D” is circulated through the steel pipe through a PVC tube at a flow rate of 1500 cc / min, and a surface temperature of 12 ° C.
A steel pipe collector was obtained. Example 2 Example 1 except that water cooled to 15 ° C. in a cooler is circulated.
In the same manner as above, a steel pipe collector having a surface temperature of 17 ° C. was obtained. Comparative Example 1 Example 1 except that water cooled to 20 ° C. in a cooler was circulated.
In the same manner as above, a steel pipe collector having a surface temperature of 22 ° C. was obtained. Comparative Example 2 A steel pipe collector having a surface temperature of 23 ° C. was obtained in the same manner as in Example 1 except that the water cooled by the cooler was not circulated.

Test Example 1 The steel pipe collecting material obtained as described above was heated to a temperature of 23.
In a spray coating booth environment with a temperature of 59 ° C, a humidity of 59% and a dew point of 18 ° C, a room-temperature drying type water-based rust preventive coating "OVAS AW # 70" manufactured by Shinto Paint Co., Ltd. with a solid content of 36% is used, and a discharge amount of 300 g / Less spray painting for 5 seconds / minute and then leaving for 60 seconds 36 times for a total of 900
The paint of 3 g was airless spray-painted without placing the article to be painted. After that, the mixture was left for 10 minutes, and the weight of the recovered coating material collected in the overspray coating material recovery container placed below the collection material and the solid content of the recovered coating material were measured. Further, a paint whose solid content of the recovered paint was adjusted to 36% with water was obtained, and the weight of the adjusted paint was measured. Further, the weight of the adjusted paint relative to the weight of the paint was measured as the recovery rate. The results are shown in Table 1. As described above, according to the water-based coating method of the present invention, in a spray coating booth used when coating an article, the oversprayed coating material can be easily collected and used as it is or as a coating material that can be reused by simple adjustment. It is possible to collect the paint and save the paint, and because the amount of paint waste is reduced, it is not necessary to dispose of the filter of the spray painting booth or the wet dust collector for a long period of time or to separate the solid and liquid. It is clear that

[0015]

[Table 1]

[0016]

According to the method for recovering the water-based paint of the present invention,
A method for recovering a water-based paint adapted for the purpose of easily recovering oversprayed paint in a spray painting booth used when painting an article and recovering it as a paint that can be reused as it is or with simple adjustment. Is suitable as

Claims (1)

[Claims] 1. In a spray coating booth used for coating articles, a surface relative temperature with respect to the spray coating booth temperature is cooled to a dew point temperature or lower in front of a filter or a wet dust collector that collects oversprayed aqueous paint. A method for recovering a water-based paint, characterized by installing the collected material.