Abstract: A method for treating a circulating water in a wet paint booth, the method including adding a treatment agent including an aqueous solution including a tannin and an alkali metal hydroxide and/or an alkali metal carbonate to the circulating water in any of passages for the circulating water in the wet paint booth, wherein the passages include for supplying the circulating water from a water tank to a paint booth, for collecting an uncoated paint in the circulating water, and for returning the circulating water to the water tank; to detackify the uncoated paint collected in the circulating water.

Abstract: To efficiently perform an adhesion reduction treatment of water that circulates through a wet paint booth which contains a solvent-based paint by adding a relatively small amount of chemical to the water without the need for another chemical except that the alkaline chemical is used for pH adjustment, that is, with only one chemical. An aluminum salt having a basicity of 60% or more and an alkaline chemical are added to water that circulates through a wet paint booth which contains a solvent-based paint. An adhesion reduction treatment of the solvent-based paint is performed at a pH of 7 or more and is preferably performed at a pH of 7.5 or more. Using a powder mixture produced by mixing a powder of the aluminum salt with a powder of the alkaline chemical facilitates the treatment.

Abstract: To efficiently perform an adhesion reduction treatment of water that circulates through a wet paint booth which contains a solvent-based paint by adding a relatively small amount of chemical to the water without the need for another chemical except that the alkaline chemical is used for pH adjustment, that is, with only one chemical. An aluminum salt having a basicity of 60% or more and an alkaline chemical are added to water that circulates through a wet paint booth which contains a solvent-based paint. An adhesion reduction treatment of the solvent-based paint is performed at a pH of 7 or more and is preferably performed at a pH of 7.5 or more. Using a powder mixture produced by mixing a powder of the aluminum salt with a powder of the alkaline chemical facilitates the treatment.

Abstract: Provided is an agent for treating water circulating through a wet paint booth, the agent being capable of reducing the adhesion of a solvent-based paint and coagulating a solvent-based paint to a sufficient degree regardless of the type of the paint, the type of the curing agent used, or the facility conditions, the agent also being capable of markedly reducing the foaming of a water-based paint, even when being used in a small amount. An agent for treating water circulating through a wet paint booth includes a phenolic resin having a weight-average molecular weight of more than 3,000 and 100,000 or less, the phenolic resin serving as an active component. A method for treating circulating water circulating through a wet paint booth includes coagulating a water-based paint and/or a solvent-based paint included in the circulating water by adding the agent to the circulating water.

Abstract: An adequate control of a pH of circulating water circulating through a wet paint booth enables an efficient coagulation treatment of a paint included in the circulating water. A method for treating circulating water circulating through a wet paint booth and including a paint includes treating the paint included in the circulating water by adding an alkaline solution of a phenolic resin to the circulating water, and adjusting a pH of the circulating water to 6.5 to 8.0. An amount of the alkaline solution of the phenolic resin added to the circulating water is increased when the pH of the circulating water is a predetermined value of 8.0 or less. An acidic aluminum salt is further added to the circulating water. An amount of the acidic aluminum salt added to the circulating water is increased when the pH of the circulating water is a predetermined value of 6.5 or more.

Abstract: A method for treating a circulating water in a wet paint booth, the method including adding a treatment agent including an aqueous solution including a tannin and an alkali metal hydroxide and/or an alkali metal carbonate to the circulating water in any of passages for the circulating water in the wet paint booth, wherein the passages include for supplying the circulating water from a water tank to a paint booth, for collecting an uncoated paint in the circulating water, and for returning the circulating water to the water tank; to detackify the uncoated paint collected in the circulating water.