Method for capturing a water treatment agent, paint, and water treatment method for a wet painting booth

Abstract

The present application relates to a kind of wet painting room circulating water treatment agent for the paint in the wet painting room circulating water of solvent-based paint and its manufacturing method, solvent-based paint trapping method and the treatment method of the wet painting room circulating water of solvent-based paint.The wet painting room circulating water treatment agent of the present application contains phenolic resin, hydrophobic cationic polymer and clay mineral, which are independently encapsulated, and the mass content ratio of phenolic resin, hydrophobic cationic polymer and clay mineral is 1-5:0.1-0.5:2-5.The present application can better make it not sticky when treating paint with high curing agent content, the paint residue floating rate is high, and the moisture content of discharged paint residue is low, which can reduce the discharge of waste, extend the water change cycle and system maintenance cycle, save water resources and manpower.

Description

Technical Field

[0001] The present invention relates to a wet coating room circulating water treatment agent for non-stick treatment of coatings in the circulating water of a wet coating room containing solvent-based coatings, a manufacturing method thereof, a method for capturing solvent-based coatings, and a method for treating the circulating water of a wet coating room containing solvent-based coatings. Background Art

[0002] As environmental protection laws and regulations become increasingly complete, more and more factories have increasingly detailed water management requirements.

[0003] In factories that produce automobiles, electrical equipment, metal products, etc., spray coating is required in the coating process, which produces a large amount of overspray paint (uncoated paint) that is not applied to the coated objects. Except for electrostatic coating with high coating efficiency, the amount of uncoated paint produced reaches about 50% to 60% of the paint used. Therefore, it is necessary to remove the uncoated paint from the environment of the coating process and recycle it. Usually, a wet coating room based on water washing is used to capture the uncoated paint, and the washing water is recycled. In order to prevent the paint from remaining and accumulating in the circulating water, the uncoated paint in the circulating water is agglomerated and separated.

[0004] Paints are broadly divided into solvent-based paints, which use only organic solvents such as thinners, and water-based paints, which use water. Compared to water-based paints, solvent-based paints offer superior weather resistance and peeling resistance, and are particularly popular for automotive topcoats and clear coatings. When using solvent-based paints, uncoated particles trapped in circulating water are highly sticky, which can cause serious contamination by adhering to various equipment or aggregate into large solids, which can easily cause blockages.

[0005] Therefore, when coagulating the circulating water of a wet paint booth containing solvent-based paint, it is very important to make the solvent-based paint non-stick.

[0006] Patent Document 1 proposes a method for making paint non-stick by adding a phenolic resin, an organic binder, and a hydrophobic cationic polymer to the circulating water in a wet painting booth. However, this method is specifically designed for making acrylic water-based paint non-stick.

[0007] The aforementioned method of adding phenolic resins, organic binders, and hydrophobic cationic polymers to make coatings non-stick is ineffective for solvent-based coatings, particularly those with high curing agent content, such as new UV coatings and 2K clearcoats. The non-sticking effect is poor, and sticky coatings are not removed, resulting in highly viscous lacquer lumps (similar to chewed gum) that cling to equipment pipes, causing equipment failures and downtime, and increasing product defect rates. Furthermore, the system requires frequent maintenance, requiring frequent replacement of the circulating water, resulting in water waste and increased production costs. Furthermore, maintenance requires significant time, labor, and resources.

[0008] Patent Document 2 discloses a method for treating circulating water in a wet painting booth. To minimize the generation of bubbles during the intermittent addition of excess water treatment agent at long intervals, and to achieve a long-lasting, non-sticking effect on the paint, hectorite and a cationic polymer coagulant are added to the circulating water in the wet painting booth. However, this method is designed for conventional solvent-based paints and exhibits poor non-sticking effects on high-curing agent-rich coatings, such as new UV coatings and 2K clearcoats. Furthermore, the discharged paint residue has a high moisture content, making it difficult to handle and resulting in high waste disposal costs.

[0009] Therefore, it is necessary to provide a wet painting room circulating water treatment agent for non-stick treatment of paint in the circulating water of a wet painting room containing solvent-based paint, and its manufacturing method, a method for capturing solvent-based paint, and a method for treating the circulating water of a wet painting room. When treating paint with a high curing agent content, the agent can better remove the stickiness, has a high paint residue floating rate, and has a low water content in the discharged paint residue, thereby reducing waste discharge, extending the water change cycle and system maintenance cycle, and saving water resources and manpower and material resources.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-149249.

[0013] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-29894. Summary of the Invention

[0014] The object of the present invention is to provide a wet painting room circulating water treatment agent for non-stick treatment of paint in the circulating water of a wet painting room containing solvent-based paint, and a manufacturing method thereof, a method for capturing solvent-based paint, and a treatment method for the circulating water of a wet painting room containing solvent-based paint. When treating paint with a high curing agent content, the agent can effectively remove viscosity, has a high paint residue floating rate, and has a low water content in the discharged paint residue, which can reduce waste discharge, extend the water change cycle and system maintenance cycle, and save water resources and manpower and material resources.

[0015] Through intensive research, the present inventors discovered that by adding a specific phenolic resin, a clay mineral, and a cationic polymer in specific proportions, solvent-based paint can be readily rendered non-sticky in circulating water, causing it to flocculate and float, resulting in small, non-sticky paint residue particles with a low moisture content. Based on these findings, the present invention was completed.

[0016] Therefore, the present invention provides the following technical solutions.

[0017] [1] A wet coating room circulating water treatment agent, which is a treatment agent for wet coating room circulating water containing solvent-based paint, characterized in that it contains a phenolic resin, a hydrophobic cationic polymer and a clay mineral, the phenolic resin, the hydrophobic cationic polymer and the clay mineral are all independently encapsulated, and the mass content ratio of the phenolic resin, the hydrophobic cationic polymer and the clay mineral is 1 to 5:0.1 to 0.5:2 to 5.

[0018] [2] The wet coating room circulating water treatment agent as described in [1] above, wherein the mass content ratio of the phenolic resin, hydrophobic cationic polymer and clay mineral is 2-3:0.25-0.35:3-4.

[0019] [3] The wet coating room circulating water treatment agent according to [1] or [2] above, wherein the phenolic resin is prepared as an alkaline aqueous solution having an alkali concentration of 1 to 25% by mass and a phenolic resin concentration of 1 to 50% by mass.

[0020] [4] The wet coating room circulating water treatment agent according to any one of [1] to [3] above, wherein the clay mineral is prepared as an aqueous suspension, and the content of the clay mineral in the aqueous suspension is 1 to 20% by mass.

[0021] [5] The wet coating room circulating water treatment agent according to any one of [1] to [4] above, wherein the hydrophobic cationic polymer is prepared as an aqueous suspension, and the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass.

[0022] [6] The wet coating room circulating water treatment agent according to any one of [1] to [5] above, wherein the phenolic resin is a phenolic resin before cross-linking and curing.

[0023] [7] The wet coating room circulating water treatment agent according to any one of [1] to [6] above, wherein the weight average molecular weight of the phenolic resin is 100 to 1000.

[0024] [8] The wet coating room circulating water treatment agent as described in any one of [1] to [7] above, wherein the hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of (meth)acrylate and a benzyl group bonded to the nitrogen atom of the quaternary ammonium salt.

[0025] [9] The wet coating room circulating water treatment agent according to any one of [1] to [8] above, wherein the weight average molecular weight of the hydrophobic cationic polymer is 9,000,000 to 11,000,000.

[0026]

[10] The wet coating room circulating water treatment agent according to any one of [1] to [9] above, wherein the clay mineral is hectorite.

[0027]

[11] The wet coating room circulating water treatment agent as described in

[10] above, wherein the hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

[0028]

[12] A method for producing a circulating water treatment agent for a wet painting room, which is the method for producing a circulating water treatment agent for a wet painting room as described in any one of [1] to

[11] above, characterized in that it includes a step of independently encapsulating the phenolic resin, hydrophobic cationic polymer and clay mineral.

[0029]

[13] A method for capturing solvent-based paint, characterized in that it includes a step of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral, wherein the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to water containing the solvent-based paint so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass, and the amount of the clay mineral added is 2 to 5% by mass relative to 100% by mass of the solvent-based paint.

[0030]

[14] A method for capturing solvent-based paint as described in

[13] above, wherein, in the step of adding phenolic resin, hydrophobic cationic polymer and clay mineral, phenolic resin, hydrophobic cationic polymer and clay mineral are added to water containing solvent-based paint so that the amount of phenolic resin added is 2 to 3% by mass, the amount of hydrophobic cationic polymer added is 0.25 to 0.35% by mass, and the amount of clay mineral added is 3 to 4% by mass relative to 100% by mass of the solvent-based paint content.

[0031]

[15] A method for capturing a solvent-based coating as described in

[13] or

[14] above, which includes a step of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline concentration of the alkaline aqueous solution is 1 to 25% by mass and the concentration of the phenolic resin is 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0032]

[16] A method for capturing a solvent-based coating as described in any one of

[13] to

[15] above, comprising the step of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the clay mineral added in the step of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral.

[0033]

[17] A method for capturing a solvent-based coating as described in any one of

[13] to

[16] above, comprising a step of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the hydrophobic cationic polymer to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0034]

[18] The method for capturing a solvent-based coating as described in any one of

[13] to

[17] above, wherein the phenolic resin is a phenolic resin before cross-linking and curing.

[0035]

[19] The method for capturing a solvent-based coating as described in any one of

[13] to

[18] above, wherein the weight average molecular weight of the phenolic resin is 100 to 1000.

[0036]

[20] A method for capturing a solvent-based coating as described in any one of

[13] to

[19] above, wherein the hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of a (meth)acrylate and having a benzyl group bonded to a nitrogen atom of the quaternary ammonium salt.

[0037]

[21] The method for capturing a solvent-based coating as described in any one of

[13] to

[20] above, wherein the weight average molecular weight of the hydrophobic cationic polymer is 9 million to 11 million.

[0038]

[22] The method for capturing a solvent-based coating as described in any one of

[13] to

[21] above, wherein the clay mineral is hectorite.

[0039]

[23] The method for capturing solvent-based coatings as described in

[22] above, wherein the hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

[0040]

[24] A method for treating circulating water in a wet coating room containing solvent-based paint, characterized in that it includes a process of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral, in which the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to any path of the wet coating room circulating water that supplies the wet coating room circulating water from a water tank to the coating room, captures uncoated solvent-based paint, and then returns to the water tank, so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass, and the amount of the clay mineral added is 2 to 5% by mass relative to 100% by mass of the content of uncoated solvent-based paint.

[0041]

[25] A method for treating circulating water in a wet coating room as described in

[24] above, wherein, in the step of adding phenolic resin, hydrophobic cationic polymer and clay mineral, phenolic resin, hydrophobic cationic polymer and clay mineral are added to any path of the wet coating room circulating water that supplies the wet coating room circulating water from the water tank to the coating room, captures uncoated solvent-based paint and then returns to the water tank, so that the amount of the phenolic resin added is 2 to 3 mass%, the amount of the hydrophobic cationic polymer added is 0.25 to 0.35 mass% and the amount of the clay mineral added is 3 to 4 mass% relative to the content of the uncoated solvent-based paint of 100 mass%.

[0042]

[26] A method for treating circulating water in a wet coating room as described in

[24] or

[25] above, wherein the method includes a step of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline concentration of the alkaline aqueous solution is 1 to 25% by mass and the concentration of the phenolic resin is 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0043]

[27] A method for treating circulating water in a wet coating room as described in any one of

[24] to

[26] above, which includes a step of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the clay mineral added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0044]

[28] A method for treating circulating water in a wet coating room as described in any one of

[24] to

[27] above, wherein the method comprises a step of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the hydrophobic cationic polymer to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0045]

[29] The method for treating circulating water in a wet coating room as described in any one of

[24] to

[28] above, wherein the phenolic resin is a phenolic resin before cross-linking and curing.

[0046]

[30] The method for treating circulating water in a wet coating room as described in any one of

[24] to

[29] above, wherein the weight average molecular weight of the phenolic resin is 100 to 1000.

[0047]

[31] A method for treating circulating water in a wet coating room as described in any one of

[24] to

[30] above, wherein the hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of (meth)acrylate and having a benzyl group bonded to the nitrogen atom of the quaternary ammonium salt.

[0048]

[32] The method for treating circulating water in a wet coating room as described in any one of

[24] to

[31] above, wherein the weight average molecular weight of the hydrophobic cationic polymer is 9 million to 11 million.

[0049]

[33] The method for treating circulating water in a wet coating room as described in any one of

[24] to

[32] above, wherein the clay mineral is hectorite.

[0050]

[34] The method for treating circulating water in a wet coating room as described in

[33] above, wherein the hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

[0051] The wet painting room circulating water treatment agent of the present invention can effectively remove viscosity when treating paint with a high curing agent content, and the paint residue floating rate is high. It can also reduce the water content of the paint residue discharged from the wet painting room circulating water, reduce the discharge of waste, extend the water change cycle and system maintenance cycle of the wet painting room circulating water, and save water resources and manpower and material resources.

[0052] The above-mentioned wet-type painting room circulating water treatment agent of the present invention can be produced by the method for producing the wet-type painting room circulating water treatment agent of the present invention.

[0053] The method for capturing solvent-based paint of the present invention can better capture solvent-based paint in water containing solvent-based paint with a high curing agent content, with a high paint residue floating rate and a low water content in the discharged paint residue, thereby reducing waste discharge, extending the water change cycle and system maintenance cycle, and saving water resources and manpower and material resources.

[0054] The method for treating circulating water in a wet painting room containing solvent-based paint of the present invention can make the uncoated paint captured by the circulating water non-adhesive when treating paint with a high curing agent content, and the paint residue has a high floating rate, and the water content of the discharged paint residue is low, thereby reducing the discharge of waste, extending the water change cycle and system maintenance cycle, and saving water resources and manpower and material resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram showing an example of the configuration of a wet coating booth.

[0056] The description of the accompanying drawings is as follows:

[0057] 1: Painting room; 2: Drip board; 3: Venturi port; 4: Water-gas separation chamber; 5: Air filter bag; 6: Circulating water tank; 7: Paint residue pump; 8: Paint residue recovery device; 9: Paint residue recovery container; 10: Water washing chamber; 11: Circulating water pump; 12: Exhaust fan. DETAILED DESCRIPTION

[0058] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0059] [Phenolic resin]

[0060] The phenolic resin used in the present invention may be, for example, a condensate of a phenol such as phenol, cresol, or xylenol with an aldehyde such as formaldehyde, or a modified product thereof before crosslinking and curing. The molecular weight of these phenolic resins is, for example, 100 to 1000, preferably 200 to 500.

[0061] Specific examples include the following condensates of phenol and formaldehyde, condensates of cresol and formaldehyde, condensates of xylenol and formaldehyde, and alkyl-modified phenolic resins obtained by alkylating the above-mentioned phenolic resins.

[0062] These phenolic resins may be of novolac type, resol type, or a mixture thereof.

[0063] As the novolac-type phenolic resin and the resol-type phenolic resin, phenolic resins represented by the following general formulas (I) and (II) are preferred.

[0064] <Novolac-type phenolic resin>

[0065]

[0066] The molecular weight is preferably 1000 or less, n is less than 10, preferably 1 or more, and m is less than 0.5, preferably 0 or more.

[0067] <Resol-type phenolic resin>

[0068]

[0069] Among them, p, q = 0~2.

[0070] The phenolic resin described above is poorly soluble in water and is preferably used in the form of a solution or emulsion by dissolving or dispersing it in a water-soluble solvent, or in the form of an alkaline aqueous solution. Examples of the solvent include water-soluble organic solvents such as ketones such as acetone, esters such as methyl acetate, and alcohols such as methanol. Examples of the alkaline aqueous solution include aqueous solutions of NaOH, KOH, amines, and the like.

[0071] When the phenolic resin is used as an alkaline aqueous solution, the alkaline aqueous solution preferably has an alkaline agent concentration of 1 to 25% by weight and a phenolic resin concentration of 1 to 50% by weight.

[0072] The hardness of the water used in the present invention is not particularly limited, but from the perspective of suppressing precipitates, the hardness is preferably 0 to 120 mg / l, more preferably 0 to 60 mg / l, even more preferably 0 to 10 mg / l, and most preferably 0 mg / l. In the present invention, pure water, such as deionized water and distilled water, is preferably used.

[0073] It should be noted that, in the present invention, the weight-average molecular weight of the phenolic resin is measured by GPC (gel permeation chromatography). Specifically, the weight-average molecular weight measurement sample is prepared as a tetrahydrofuran solution of the sample, an HLC-8120GPC manufactured by Toso Co., Ltd. is used as an analysis device (GPC), tetrahydrofuran is used as a solvent, and the weight-average molecular weight is calculated based on standard polystyrene conversion.

[0074] [Hydrophobic cationic polymer]

[0075] Examples of the hydrophobic cationic polymer used in the present invention include a polymer having a cationic structural unit derived from a quaternary ammonium salt of a (meth)acrylate, wherein a benzyl group is bonded to the nitrogen atom of the quaternary ammonium salt.

[0076] As the hydrophobic cationic polymer, a polymer composed of the structural unit (A) represented by the following general formula (III) can be used.

[0077]

[0078] In the general formula (III), R 1 represents a hydrogen atom or a methyl group, R 2 and R 3 Each independently represents an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

[0079] A 1 represents a linear or branched alkylene group having 2 to 4 carbon atoms, and examples thereof include ethylene, propylene, trimethylene, and various butylene groups. (X 1 ) a- An anion having a valence of a. a is generally an integer of 1 to 3. Specific examples of such anions include chloride, fluoride, bromide, iodide, sulfate, nitrate, phosphate, methylsulfate, and perchlorate. Of these, chloride, fluoride, bromide, and iodide are preferred.

[0080] Examples of the quaternary ammonium salt of (meth)acrylate as a monomer forming the structural unit (A) include (meth)acryloyloxyalkyl(benzyl)dialkylammonium salts, and specifically include [2-(acryloyloxy)ethyl]benzyldimethylammonium salt, [2-(acryloyloxy)ethyl]benzyldiethylammonium salt, [2-(acryloyloxy)ethyl]benzylethylmethylammonium salt, [2-(methacryloyloxy)ethyl]benzyldimethylammonium salt, [2-(methacryloyloxy)ethyl]benzyl [2-(methacryloyloxy)ethyl]benzylethylmethylammonium salt, [3-(acryloyloxy)propyl]benzyldimethylammonium salt, [3-(acryloyloxy)propyl]benzyldiethylammonium salt, [3-(acryloyloxy)propyl]benzylethylmethylammonium salt, [3-(methacryloyloxy)propyl]benzyldimethylammonium salt, [3-(methacryloyloxy)propyl]benzyldiethylammonium salt, [3-(methacryloyloxy)propyl]benzylethylmethylammonium salt, and the like.

[0081] These monomers may be used alone or in combination of two or more.

[0082] The cationic hydrophobic polymer used in the present invention can be a copolymer composed of the above-mentioned (A) structural unit and a nonionic structural unit and / or other cationic structural units. There is no particular limitation on the above-mentioned nonionic structural unit and other cationic structural unit, but the following copolymers can be preferably used.

[0083] The cationic hydrophobic polymer used in the present invention is preferably a copolymer (hereinafter referred to as copolymer I) having the above-mentioned (A) structural unit and the nonionic (B) structural unit represented by the following general formula (IV).

[0084]

[0085] In the general formula (IV), R 4 represents a hydrogen atom or a methyl group, R 5 and R 6 Each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a dimethylaminoalkyl group. Examples of the alkyl group having 1 to 3 carbon atoms include methyl, ethyl, n-propyl, and isopropyl. Examples of the dimethylaminoalkyl group include 2-dimethylaminoethyl and 3-dimethylaminopropyl.

[0086] Examples of the monomer forming the structural unit (B) include (meth)acrylamides such as acrylamide, N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-diisopropylacrylamide, N-ethyl-N-methylacrylamide, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-isopropylmethacrylamide, N,N-dimethylmethacrylamide, N,N-diethylmethacrylamide, N,N-diisopropylmethacrylamide, N-ethyl-N-methylmethacrylamide, N-(2-dimethylaminoethyl)acrylamide, N-(2-dimethylaminoethyl)methacrylamide, N-(3-dimethylaminopropyl)acrylamide, and N-(3-dimethylaminopropyl)methacrylamide.

[0087] These monomers may be used alone or in combination of two or more.

[0088] From the viewpoint of coagulation performance against uncoated coatings, the molar ratio of the constituent units (A) to (B) in the copolymer I is preferably 2:8 to 9:1, more preferably 3:7 to 6:4.

[0089] The cationic hydrophobic polymer used in the present invention is preferably a copolymer (hereinafter referred to as copolymer II) having the above-mentioned (A) structural unit and a cationic (C) structural unit represented by the following general formula (V).

[0090]

[0091] In the general formula (V), R 7 represents a hydrogen atom or a methyl group, R 8 、R 9 and R 10 Each independently represents an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

[0092] A 2 represents a linear or branched alkylene group having 2 to 4 carbon atoms, and specific examples thereof include ethylene, propylene, trimethylene, and various butylene groups. (X 2 ) b- An anion having a valence of b. b is generally an integer from 1 to 3. Specific examples of such anions include chloride, fluoride, bromide, iodide, sulfate, nitrate, phosphate, methylsulfate, and perchlorate. Among these, chloride, fluoride, bromide, and iodide are preferred.

[0093] Examples of the monomer forming the structural unit (C) include (meth)acryloyloxyalkyl (trialkyl) ammonium salts, specifically [2-(acryloyloxy)ethyl]trimethylammonium salt, [2-(acryloyloxy)ethyl]triethylammonium salt, [2-(acryloyloxy)ethyl]ethyldimethylammonium salt, [2-(methacryloyloxy)ethyl]trimethylammonium salt, [2-(methacryloyloxy)ethyl]triethylammonium salt, [2-(methacryloyloxy)ethyl]ethyldimethylammonium salt, [3-(acryloyloxy)propyl]trimethylammonium salt, [3-(acryloyloxy)propyl]triethylammonium salt, [3-(acryloyloxy)propyl]ethyldimethylammonium salt, [3-(methacryloyloxy)propyl]trimethylammonium salt, [3-(methacryloyloxy)propyl]triethylammonium salt, [3-(methacryloyloxy)propyl]ethyldimethylammonium salt, and the like.

[0094] These monomers may be used alone or in combination of two or more.

[0095] From the viewpoint of coagulation performance against uncoated coatings, the molar ratio of the constituent units (A) to (C) in the copolymer II is preferably 8:2 to 2:8, more preferably 6:4 to 4:6.

[0096] As the cationic hydrophobic polymer used in the present invention, a copolymer (hereinafter referred to as copolymer III) having the aforementioned (A) structural unit, the aforementioned nonionic (B) structural unit, and the aforementioned cationic (C) structural unit can be particularly preferably used.

[0097] From the viewpoint of the coagulation performance of the uncoated coating, the content ratios of the above-mentioned (A) constituent unit, (B) constituent unit and (C) constituent unit in the copolymer III are preferably 5 to 90%, 30 to 90% and 0 to 90%, respectively, on a molar basis, and more preferably 10 to 40%, 50 to 70% and 10 to 40%, respectively.

[0098] Representative examples of the copolymer III include acrylamide / [2-(acryloyloxy)ethyl]benzyldimethylammonium chloride / [2-(acryloyloxy)ethyl]trimethylammonium chloride, acrylamide / [3-(acryloyloxy)propyl]benzyldimethylammonium chloride / [2-(acryloyloxy)ethyl]trimethylammonium chloride, acrylamide / [2-(acryloyloxy)ethyl]benzyldimethylammonium chloride / [3-(acryloyloxy)propyl]trimethylammonium chloride, and acrylamide / [3-(acryloyloxy)propyl]benzyldimethylammonium chloride / [3-(acryloyloxy)propyl]trimethylammonium chloride.

[0099] From the perspective of coagulation performance against uncoated coatings, the weight-average molecular weight of the cationic hydrophobic polymer used in the present invention is a value converted to polyethylene glycol, as measured by gel permeation chromatography (GPC) using a 0.1 mol / L sodium chloride aqueous solution as the eluent, and is preferably 6 million or more, more preferably 9 million to 11 million.

[0100] The polymerization method of the hydrophobic cationic polymer is not particularly limited, and a general polymerization method can be employed.

[0101] The cationic hydrophobic polymer can be used in any form of an aqueous solution, a suspension, or an emulsion.

[0102] The hydrophobic cationic polymer of the present invention is preferably dispersed in water and supplied as an aqueous suspension.

[0103] The amount of the hydrophobic cationic polymer contained in the aqueous suspension of the hydrophobic cationic polymer of the present invention is 1 to 20% by mass, preferably 3 to 15% by mass, and more preferably 5 to 10% by mass relative to the mass of the aqueous suspension.

[0104] The hardness of the water used in the present invention is not particularly limited, but from the perspective of suppressing precipitates, the hardness is preferably 0 to 120 mg / l, more preferably 0 to 60 mg / l, even more preferably 0 to 10 mg / l, and most preferably 0 mg / l. In the present invention, pure water, such as deionized water and distilled water, is preferably used.

[0105] [Clay minerals]

[0106] Clay minerals used in the present invention include, for example, clay minerals of the kaolinite group, illite group, montmorillonite group, vermiculite group, and sepiolite group. These may be used alone or in combination of two or more.

[0107] The clay mineral of the present invention is preferably Na 0.3 (Mg,Li)3Si4O 10 The hectorite represented by (OH)2 has a negative charge when prepared as an aqueous suspension. The hectorite of the present invention may be naturally occurring or artificially synthesized.

[0108] The hectorite of the present invention is preferably dispersed in water and supplied as an aqueous suspension.

[0109] The amount of hectorite contained in the aqueous suspension of hectorite of the present invention is 1 to 20% by mass, preferably 3 to 15% by mass, and more preferably 5 to 10% by mass, based on the mass of the aqueous suspension.

[0110] The volume average particle size of the hectorite used in the present invention is preferably 0.01 to 2 μm, more preferably 0.01 to 1 μm. If the particle diameter is too large, it tends to be difficult to maintain a suspended state. If the particle diameter is too small, it tends to settle or gel due to aggregation.

[0111] A dispersant may be used in the aqueous suspension of the hectorite of the present invention, and an acrylate polymer may be used as the dispersant.

[0112] The hardness of the water used in the present invention is not particularly limited, but from the perspective of suppressing precipitates, the hardness is preferably 0 to 120 mg / l, more preferably 0 to 60 mg / l, even more preferably 0 to 10 mg / l, and most preferably 0 mg / l. In the present invention, pure water, such as deionized water and distilled water, is preferably used.

[0113] [Wet coating room circulating water treatment agent]

[0114] The wet coating room circulating water treatment agent of the present invention is a treatment agent for the wet coating room circulating water containing solvent-based paint, and is characterized in that it contains a phenolic resin, a hydrophobic cationic polymer and a clay mineral, and the phenolic resin, hydrophobic cationic polymer and clay mineral are all independently encapsulated, and the mass content ratio of the phenolic resin, hydrophobic cationic polymer and clay mineral is 1 to 5:0.1 to 0.5:2 to 5.

[0115] In the wet coating room circulating water treatment agent of the present invention, the mass content ratio of the phenolic resin, the hydrophobic cationic polymer and the clay mineral is preferably 2-3:0.25-0.35:3-4.

[0116] In factories producing automobiles, electrical equipment, metal products, etc., spray coating is required during the coating process, which produces a large amount of overspray paint (uncoated paint) that is not applied to the object being coated. The uncoated paint needs to be removed from the environment of the coating process and recycled. Usually, a wet coating room based on water washing is used to capture the uncoated paint, and the washing water is recycled. In order to prevent the paint from remaining and accumulating in the circulating water, the uncoated paint in the circulating water is agglomerated and separated. When using solvent-based paint, the particles of uncoated paint captured in the circulating water have high adhesion, so they will adhere to various equipment and cause serious pollution, or agglomerate into large solids and easily form blockages.

[0117] The wet coating room circulating water treatment agent of the present invention makes the hydrophobic solvent-based paint non-adhesive through the chemical reaction, causes it to flocculate and float, removes the paint residue, and then the treated water is continuously circulated for use.

[0118] Although the mechanism of action is not too clear, but, can be inferred as, on the nitrogen-atoms of quaternary ammonium salt, in conjunction with benzyl and form the polymer of the cationic constituent unit with the quaternary ammonium salt that derives from (methyl) acrylate, on the benzyl that hydrophobicity is strong, be combined with the hydrophobic part of uncoated coating, make uncoated coating agglomeration, and this polymer easily reacts with the phenolic resin that is charged as anionic and forms strong hydrophobic particles and is coated on the coating, in addition, the clay mineral that has negative charge also easily reacts with this polymer, and promotes this polymer to the effect of uncoated coating agglomeration. As its result, firmly form thick flocculate. In addition, because this polymer is strong hydrophobicity, so this flocculate obtains and easily separates with water, floats the effect easily.

[0119] There is no particular restriction on the form of the wet coating room for the wet coating room circulating water treatment agent of the present invention. For example, it can be a rinse type, a non-pump type, a water curtain type, a Venturi type, etc., and is basically composed of a blowing chamber, an air suction device, an exhaust system and a circulating water system.

[0120] Below, use Figure 1 The schematic diagram of a Venturi-type painting booth shown in FIG. 1 will explain the outline of the wet painting booth circulating water treatment using the wet painting booth circulating water treatment agent of the present invention.

[0121] like Figure 1 As shown, an inverted trumpet-shaped exhaust hood is installed beneath the grille of the painting booth 1. The hood's shape gradually tapers from top to bottom, causing the air entering the room from the ceiling to gradually contract, forming a laminar flow, which is then discharged through the gap in the center of the hood. The wet painting booth circulating water flowing down the drip plate 2 forms a water curtain wall at the Venturi port 3. Air containing solvent-based paint is carried by the laminar airflow to the exhaust hood, where the airflow meets the water curtain wall. As the airflow passes through the water curtain wall, the solvent-based paint is trapped in the circulating water. In the water-gas separation chamber 4, the gas is separated from the circulating water containing solvent-based paint. The air then passes through the air filter bag 5 and is discharged to the atmosphere via the exhaust fan 12. The circulating water then flows back to the circulating water tank 6, where it is treated with a wet painting booth circulating water treatment agent to form paint residue. This residue is then sent to the paint residue recovery device 8 via a paint residue pump 7, where solid-liquid separation is performed. The solid matter after solid-liquid separation is recovered as paint sludge in the paint residue recovery container 9. A filter is provided in the circulating water tank 6 to form a washing water chamber 10, and the water in the washing water chamber is circulated to the coating room 1 by a circulating water pump 11. After the solid-liquid separation, the water passes through the filter and the circulating water pipeline and returns to the circulating water tank 6.

[0122] The wet coating room circulating water treatment agent of the present invention can be added to the wet coating room circulating water in any path of the wet coating room circulating water, which supplies the wet coating room circulating water from the water tank to the coating room, collects the unapplied solvent-based paint, and then returns to the water tank. The wet coating room circulating water treatment agent of the present invention can be added to the wet coating room circulating water in any path of the wet coating room circulating water, as long as the amount is 1 part by mass relative to 100 parts by mass of the unapplied solvent-based paint content.

[0123] [Method for producing a circulating water treatment agent for a wet coating room]

[0124] The method for producing a wet painting room circulating water treatment agent of the present invention is the above-mentioned method for producing a wet painting room circulating water treatment agent, characterized in that it includes a step of independently encapsulating the phenolic resin, hydrophobic cationic polymer and clay mineral.

[0125] The method of independently encapsulating the phenolic resin, hydrophobic cationic polymer and clay mineral may be a method known in the art, for example, the phenolic resin, hydrophobic cationic polymer and clay mineral are independently packed into glass bottles, plastic bags and the like.

[0126] After the phenolic resin, the hydrophobic cationic polymer and the clay mineral are packaged independently, the three can be combined and assembled together, for example, in a box or a glass container.

[0127] [Method for capturing solvent-based paint]

[0128] The method for capturing solvent-based paint of the present invention is characterized in that it includes a step of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral. In this step, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to water containing the solvent-based paint so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass, and the amount of the clay mineral added is 2 to 5% by mass, relative to 100% by mass of the solvent-based paint content.

[0129] In the method for capturing solvent-based paint of the present invention, it is preferred that in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to the water containing the solvent-based paint so that the amount of the phenolic resin added is 2 to 3% by mass, the amount of the hydrophobic cationic polymer added is 0.25 to 0.35% by mass, and the amount of the clay mineral added is 3 to 4% by mass, relative to 100% by mass of the content of the solvent-based paint.

[0130] In the method for capturing solvent-based coatings of the present invention, the adding method may be a method known in the art, for example, the phenolic resin, hydrophobic cationic polymer and clay mineral are added to different parts or the same part of the water containing the solvent-based coating through a feeder, and stirred at the same time or after the addition to fully disperse them. Preferably, they are added to different parts of the water containing the solvent-based coating and stirred at the same time or after the addition to fully disperse them.

[0131] The method for capturing solvent-based paint of the present invention preferably includes a step of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline aqueous solution has an alkali concentration of 1 to 25% by mass and a phenolic resin concentration of 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0132] The method for capturing a solvent-based coating of the present invention preferably includes a step of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the clay mineral added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0133] The method for capturing a solvent-based coating of the present invention preferably includes a step of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the hydrophobic cationic polymer added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0134] [Treatment method of circulating water in wet coating room]

[0135] The method for treating circulating water in a wet painting room of the present invention is characterized in that it includes a step of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral. In this step, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to any path of the wet painting room circulating water that supplies the wet painting room circulating water from a water tank to the painting room, captures uncoated solvent-based paint, and then returns to the water tank, so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass, and the amount of the clay mineral added is 2 to 5% by mass relative to 100% by mass of the content of the uncoated solvent-based paint.

[0136] In the method for treating circulating water in a wet painting room of the present invention, it is preferred that in the step of adding phenolic resin, hydrophobic cationic polymer and clay mineral, phenolic resin, hydrophobic cationic polymer and clay mineral are added to any path of the wet painting room circulating water that supplies the circulating water from the water tank to the painting room, captures uncoated solvent-based paint and then returns to the water tank, so that the amount of the phenolic resin added is 2 to 3 mass%, the amount of the hydrophobic cationic polymer added is 0.25 to 0.35 mass% and the amount of the clay mineral added is 3 to 4 mass% relative to 100 mass% of the content of the uncoated solvent-based paint.

[0137] The method for treating circulating water in a wet coating room of the present invention preferably includes a step of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline concentration of the alkaline aqueous solution is 1 to 25% by mass and the phenolic resin concentration is 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0138] The method for treating circulating water in a wet coating room of the present invention preferably includes a step of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the clay mineral added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0139] The method for treating circulating water in a wet coating room of the present invention preferably includes a step of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and the aqueous suspension is used as the hydrophobic cationic polymer added in the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral.

[0140] In the method for treating circulating water in a wet coating room of the present invention, it is preferred that a hydrophobic cationic polymer and a clay mineral are added to the circulating water on the upstream side of the circulating water tank of the wet coating room, and a phenolic resin and a hydrophobic cationic polymer are added to the circulating water on the downstream side of the above-mentioned circulating water tank.

[0141] By adding a hydrophobic cationic polymer and a clay mineral to the circulating water upstream of the circulating water pipe, the hydrophobic cationic polymer and the clay mineral react to form particles. These particles quickly coat the surface of the solvent-based paint, removing its stickiness and effectively agglomerating the unapplied paint. Meanwhile, by adding a phenolic resin and a hydrophobic cationic polymer to the circulating water downstream of the tank, the phenolic resin and the hydrophobic cationic polymer react to form particles. These particles coat the surface of the solvent-based paint, easily forming paint residue particles with a low moisture content.

[0142] As a method for adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral to the circulating water, any method known in the art may be used.

[0143] In the method for treating circulating water in a wet coating room of the present invention, in addition to adding phenolic resin, hydrophobic cationic polymer, and clay mineral, other known coagulants can be added. Examples of known coagulants include alumina sol, linear cationic polyamine, sodium zincate, and the like.

[0144] In the present invention's method for treating circulating water in a wet painting booth, the paint residue generated readily floats and can be easily recovered. For example, the paint residue can be separated and recovered using methods such as flotation separation, wedge wire, rotary screens, bar screens, cyclones, centrifuges, and filtration devices. The recovered paint residue can be dehydrated by gravity or conventional methods and then incinerated or buried.

[0145] Example

[0146] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following Examples are merely illustrative of the present invention and the present invention is not limited thereto.

[0147] [Use medicine]

[0148] In the following examples and comparative examples, the following agents were used.

[0149] Phenolic resin 1: a novolac-type phenolic resin manufactured by Gunei Chemical Co., Ltd. (model: PSM4324, molecular weight 800).

[0150] Phenolic resin 2: resol-type phenolic resin (model: PL3630, molecular weight 300) manufactured by Gunei Chemical Co., Ltd. of Japan.

[0151] Hydrophobic cationic polymer: acrylamide / [2(acryloyloxy)ethyl]benzyldimethylammonium chloride / [2(acryloyloxy)ethyl]trimethylammonium chloride copolymer, copolymerization molar ratio 66 / 17 / 17, weight average molecular weight 10,000,000.

[0152] Clay minerals: Na 0.3 (Mg,Li)3Si4O 10 Hectorite represented by (OH)2 has a negative charge when prepared as an aqueous suspension and has an average particle size of 1 μm.

[0153] [Use paint]

[0154] In the following examples and comparative examples, the following coating materials were used.

[0155] 2K clear varnish paint: paint produced by Nippon Paint Holdings Co., Ltd. (model: OG173).

[0156] [Test method]

[0157] use Figure 1 The experiments were carried out using the experimental setup shown.

[0158] The experimental apparatus was configured to circulate circulating water in a 100L water tank via a pump. The phenolic resin, hydrophobic cationic polymer, and clay mineral listed in Table 1 were added to the circulating water in the amounts shown in Table 1. Then, 1000g of paint was sprayed into the circulating water over a 10-minute period. After the apparatus was stopped, the paint residue moisture content, paint residue viscosity, and paint residue floating rate were measured using the following methods and evaluated according to the following criteria. The evaluation results are recorded in Table 2.

[0159] (Paint residue moisture content)

[0160] The lower the moisture content of the paint residue, the less water is contained in the formed paint residue, the less waste is recovered in the paint residue recovery container, and the easier it is to handle.

[0161] Detection of moisture content of paint residue: Take some paint residue and leave it for two hours; weigh the sample after standing, put it into a dryer at 120℃ and dry it for 30 minutes; weigh the dried sample and calculate the moisture content. The calculation formula is as follows.

[0162] Paint residue moisture content = (ba) / b × 100%

[0163] a: Weight of paint residue sample after drying.

[0164] b: Weight of paint residue sample before drying.

[0165] (Paint residue viscosity)

[0166] The lower the viscosity of the paint residue, the easier it is to handle. Conversely, the higher the viscosity of the paint residue, the more difficult it is to handle.

[0167] Immediately after stopping the apparatus, the adhesion of the paint residue floating to the water surface of the circulating water tank was checked by finger touch and evaluated based on the following criteria.

[0168] Criteria for judging the viscosity of paint residue:

[0169] ◎◎: It feels good to the touch and can be formed into a ball by rubbing with fingers.

[0170] ◎: It feels sticky to the touch and comes off easily with a wipe.

[0171] ○: It feels sticky to the touch and is difficult to remove.

[0172] ×: Adhesive residue remains.

[0173] ××: High adhesion.

[0174] (Paint residue floating rate)

[0175] The higher the paint residue floating rate is, the more paint residue is floating, and the easier it is to remove it from the circulating water of the wet coating room and transfer it to the paint residue recovery container for the next step of treatment.

[0176] The total amount of paint residue produced is weighed, and then the floating paint residue is weighed, and then the paint residue floating rate is calculated using the following formula.

[0177] Paint residue floating rate = (M1-M2) / M1×100%

[0178] M1: Total weight of paint residue.

[0179] M2: The weight of the floating paint residue.

[0180] Evaluation was conducted based on the following criteria.

[0181] The criteria for judging the paint residue floating rate are as follows.

[0182] ◎◎: More than 95% float.

[0183] ◎: 85% to 95% floating.

[0184] ○: 75% to 85% floated.

[0185] ×: 65% to 75% floating.

[0186] ××: 65% or less.

[0187] Table 1

[0188]

[0189] The results of the paint residue floating rate, paint residue viscosity, and paint residue moisture content of the examples and comparative examples are shown in Table 2.

[0190] Table 2

[0191] Paint residue moisture content Paint residue viscosity Paint residue floating rate Example 1 75.0％ ◎◎ ◎◎ Example 2 74.5％ ◎◎ ◎◎ Example 3 77.4％ ◎◎ ◎◎ Comparative Example 1 52.4％ ○ ◎◎ Comparative Example 2 56.5％ × ◎◎ Comparative Example 3 85.6％ ◎◎ ◎ Example 4 72.5％ ◎◎ ◎◎ Example 5 48.7％ ◎◎ ◎◎ Example 6 53.6％ ◎◎ ◎◎ Comparative Example 4 51.4％ ○ ◎ Comparative Example 5 51.3％ × ◎◎ Comparative Example 6 87.6％ ◎◎ ◎ Comparative Example 7 69.5％ × ◎◎ Comparative Example 8 81.5％ ○ ◎ Comparative Example 9 85.6％ ◎ ◎◎ Comparative Example 10 88.2％ ◎◎ ◎◎ Comparative Example 11 58.2％ ×× ◎◎ Comparative Example 12 88.5％ ◎◎ ◎ Comparative Example 13 97.6％ ◎◎ ×× Comparative Example 14 96.3％ ◎◎ ×× Comparative Example 15 61.2％ ×× ◎◎ Comparative Example 16 62.7％ ○ ◎◎ Comparative Example 17 56.8％ × ◎◎ Comparative Example 18 61.6％ × ◎◎ Comparative Example 19 66.2％ ×× ◎◎ Comparative Example 20 51.8％ ◎ ◎◎ Comparative Example 21 67.4％ ×× ×× Comparative Example 22 73.4％ ×× ×× Comparative Example 23 67.7％ ×× ◎◎ Comparative Example 24 62.4％ ○ ◎◎ Comparative Example 25 53.8％ × ◎◎ Comparative Example 26 60.5％ ○ ◎◎ Comparative Example 27 66.3％ ×× ◎◎ Comparative Example 28 59.8％ ◎ ◎◎ Comparative Example 29 67.4％ ×× ×× Comparative Example 30 73.4％ ×× ××

[0192] According to the above test results, the following conclusions can be drawn.

[0193] First, according to the experimental results of Examples 1-6 and Comparative Examples 1-6, it can be seen that when phenolic resin, hydrophobic cationic polymer and clay mineral are added to the circulating water of the wet coating room, so that the added amount of the phenolic resin is 1-5 mass%, the added amount of the hydrophobic cationic polymer is 0.1-0.5 mass% and the added amount of the clay mineral is 2-5 mass% relative to the content of the uncoated solvent-based paint is 100 mass%, compared with the case where the added amount exceeds this range, it is possible to obtain technical effects such as excellent paint residue moisture content, paint residue viscosity and paint residue floating rate.

[0194] In addition, according to the experimental results of Examples 1-6 and Comparative Examples 1-2 and 4-5, it can be seen that when the addition amount of the clay mineral is less than 2% by mass in the circulating water of the wet painting room, the paint residue has high viscosity and is difficult to handle.

[0195] In addition, according to the experimental results of Examples 1-6 and Comparative Examples 3 and 6, it can be seen that in the circulating water of the wet painting room, when the addition amount of the phenolic resin exceeds 5% by mass, the addition amount of the hydrophobic cationic polymer exceeds 0.5% by mass, and the addition amount of the clay mineral exceeds 5% by mass, the paint residue floating rate and the paint residue moisture content are poor.

[0196] Furthermore, the experimental results of Examples 1-6 and Comparative Examples 8-10 and 12-14 show that the addition of phenolic resin, hydrophobic cationic polymer, and clay mineral significantly reduced the moisture content of the paint residue compared to the addition of only the hydrophobic cationic polymer and clay mineral. Furthermore, while the paint residues of Comparative Examples 7 and 11 had good moisture contents, they were also highly viscous, making them difficult to handle.

[0197] In addition, according to the experimental results of Examples 1-6 and Comparative Examples 15-30, it can be seen that adding phenolic resin, hydrophobic cationic polymer, and clay mineral to the circulating water of the wet painting room can achieve the excellent effect of significantly reducing the viscosity of paint residue compared to the case of adding only hydrophobic cationic polymer and phenolic resin.

[0198] In addition, according to the experimental results of Examples 1-6 and Comparative Examples 9-10, 12-14, 18, 20-22, 26, and 28-30, it can be seen that in the circulating water of the wet painting room, simply relying on increasing the amount of clay minerals, hydrophobic cationic polymers or increasing the amount of phenolic resins, hydrophobic cationic polymers cannot obtain excellent results. When phenolic resins, hydrophobic cationic polymers, and clay minerals are added, a synergistic effect is achieved between the three, thereby achieving technical effects of excellent paint residue moisture content, paint residue viscosity, and floating rate.

[0199] In addition, in the reagent scheme system, it is necessary to achieve a balance between anions and cations between the reagents in order to obtain good results. In the above experiment, when the anions and cations are unbalanced, the moisture content and viscosity of the paint residue are very poor, and the floating effect of the paint residue is also poor. Especially when the cations are excessive, the paint residue is severely dispersed and it is difficult to conduct relevant evaluation. Therefore, the comparative example of excessive cations is not shown in the above table.

[0200] Therefore, the use of the wet painting room circulating water treatment agent of the present invention can better remove viscosity when treating paints with high curing agent content, and the paint residue floating rate is high. It can also make the water content of the paint residue discharged from the wet painting room circulating water low, reduce waste discharge, and extend the water change cycle and system maintenance cycle of the wet painting room circulating water, saving water resources and manpower and material resources.

[0201] Furthermore, the wet-type painting room circulating water treatment agent of the present invention can be produced by the method for producing the wet-type painting room circulating water treatment agent of the present invention.

[0202] The method for capturing solvent-based paint of the present invention can better capture solvent-based paint in water containing solvent-based paint with a high curing agent content, with a high paint residue floating rate and a low water content in the discharged paint residue, thereby reducing waste discharge, extending the water change cycle and system maintenance cycle, and saving water resources and manpower and material resources.

[0203] The method for treating circulating water in a wet painting room containing solvent-based paint of the present invention can make the uncoated paint captured by the circulating water non-adhesive when dealing with paint with a high curing agent content, and the paint residue has a high floating rate, and the water content of the discharged paint residue is low, thereby reducing the discharge of waste, extending the water change cycle and system maintenance cycle, and saving water resources and manpower and material resources.

[0204] Although the present invention has been described in detail above in conjunction with exemplary embodiments, it should be understood that the present invention should not be limited to the disclosed exemplary embodiments. On the contrary, any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims attached to the present invention should be included in the scope of protection of the present invention.

Claims

1. A wet coating room circulating water treatment agent, which is a treatment agent for the circulating water of a wet coating room containing solvent-based paint, characterized in that: The wet coating room circulating water treatment agent contains phenolic resin, hydrophobic cationic polymer and clay mineral. The phenolic resin, hydrophobic cationic polymer and clay mineral are all independently encapsulated. The mass content ratio of the phenolic resin, the hydrophobic cationic polymer and the clay mineral is 1-5:0.1-0.5:2-5.

2. The wet coating room circulating water treatment agent according to claim 1, wherein: The mass content ratio of the phenolic resin, the hydrophobic cationic polymer and the clay mineral is 2-3:0.25-0.35:3-4.

3. The wet coating room circulating water treatment agent according to claim 1 or 2, wherein: The phenolic resin is prepared as an alkaline aqueous solution having an alkali concentration of 1 to 25% by mass and a phenolic resin concentration of 1 to 50% by mass.

4. The wet coating room circulating water treatment agent according to claim 1 or 2, wherein: The clay mineral is prepared as an aqueous suspension, and the content of the clay mineral in the aqueous suspension is 1 to 20% by mass.

5. The wet coating room circulating water treatment agent according to claim 1 or 2, wherein: The hydrophobic cationic polymer is prepared as an aqueous suspension, and the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass.

6. The wet coating room circulating water treatment agent according to claim 1, wherein: The phenolic resin is a phenolic resin before cross-linking and curing.

7. The wet coating room circulating water treatment agent according to claim 1 or 6, wherein: The weight average molecular weight of the phenolic resin is 100 to 1000.

8. The wet coating room circulating water treatment agent according to claim 1, wherein: The hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of a (meth)acrylate, and a benzyl group is bonded to a nitrogen atom of the quaternary ammonium salt.

9. The wet coating room circulating water treatment agent according to claim 1 or 8, wherein: The weight average molecular weight of the hydrophobic cationic polymer is 9 million to 11 million.

10. The wet coating room circulating water treatment agent according to claim 1, wherein The clay mineral is hectorite.

11. The wet coating room circulating water treatment agent according to claim 10, wherein: The hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

12. A method for producing a circulating water treatment agent for a wet painting room, the method being the method for producing a circulating water treatment agent for a wet painting room according to any one of claims 1 to 11, characterized in that: The method includes the steps of independently encapsulating the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

13. A method for capturing solvent-based coatings, characterized in that: The invention comprises the step of adding a phenolic resin, a hydrophobic cationic polymer and a clay mineral. In the step, the phenolic resin, the hydrophobic cationic polymer and the clay mineral are added to water containing a solvent-based paint so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass and the amount of the clay mineral added is 2 to 5% by mass relative to 100% by mass of the content of the solvent-based paint.

14. The method for capturing solvent-based coatings according to claim 13, wherein: In the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to the water containing the solvent-based paint so that, relative to 100% by mass of the content of the solvent-based paint, the added amount of the phenolic resin is 2 to 3% by mass, the added amount of the hydrophobic cationic polymer is 0.25 to 0.35% by mass, and the added amount of the clay mineral is 3 to 4% by mass.

15. The method for capturing a solvent-based coating according to claim 13 or 14, wherein: The invention comprises the steps of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline concentration of the alkaline aqueous solution is 1 to 25% by mass and the phenolic resin concentration is 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

16. The method for capturing a solvent-based coating according to claim 13 or 14, wherein: The method comprises the steps of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the clay mineral to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

17. The method for capturing a solvent-based coating according to claim 13 or 14, wherein: The method comprises the steps of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the hydrophobic cationic polymer to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

18. The method for capturing solvent-based coatings according to claim 13, wherein: The phenolic resin is a phenolic resin before cross-linking and curing.

19. The method for capturing a solvent-based coating according to claim 13 or 18, wherein: The weight average molecular weight of the phenolic resin is 100 to 1000.

20. The method for capturing solvent-based coatings according to claim 13, wherein: The hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of a (meth)acrylate, and a benzyl group is bonded to a nitrogen atom of the quaternary ammonium salt.

21. The method for capturing a solvent-based coating according to claim 13 or 20, wherein: The weight average molecular weight of the hydrophobic cationic polymer is 9 million to 11 million.

22. The method for capturing solvent-based coatings according to claim 13, wherein: The clay mineral is hectorite.

23. The method for capturing solvent-based coatings according to claim 22, wherein: The hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

24. A method for treating circulating water in a wet coating room containing solvent-based paint, characterized in that: The method includes the step of adding a phenolic resin, a hydrophobic cationic polymer, and a clay mineral. In this step, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to any path of the wet coating room circulating water that supplies the wet coating room circulating water from a water tank to the coating room, collects unapplied solvent-based paint, and then returns to the water tank, so that the amount of the phenolic resin added is 1 to 5% by mass, the amount of the hydrophobic cationic polymer added is 0.1 to 0.5% by mass, and the amount of the clay mineral added is 2 to 5% by mass relative to 100% by mass of the content of the unapplied solvent-based paint.

25. The method for treating circulating water in a wet painting room according to claim 24, wherein: In the step of adding the phenolic resin, the hydrophobic cationic polymer, and the clay mineral, the phenolic resin, the hydrophobic cationic polymer, and the clay mineral are added to any path of the wet coating room circulating water that supplies the wet coating room circulating water from the water tank to the coating room, collects the unapplied solvent-based paint, and then returns to the water tank, so that the amount of the phenolic resin added is 2 to 3 mass%, the amount of the hydrophobic cationic polymer added is 0.25 to 0.35 mass%, and the amount of the clay mineral added is 3 to 4 mass%, relative to 100 mass% of the content of the unapplied solvent-based paint.

26. The method for treating circulating water in a wet painting room according to claim 24 or 25, wherein: The invention comprises the steps of preparing a phenolic resin into an alkaline aqueous solution, wherein the alkaline concentration of the alkaline aqueous solution is 1 to 25% by mass and the phenolic resin concentration is 1 to 50% by mass, and the alkaline aqueous solution is used as the phenolic resin added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

27. The method for treating circulating water in a wet painting room according to claim 24 or 25, wherein: The method comprises the steps of preparing a clay mineral into an aqueous suspension, wherein the content of the clay mineral in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the clay mineral to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

28. The method for treating circulating water in a wet painting room according to claim 24 or 25, wherein: The method comprises the steps of preparing a hydrophobic cationic polymer into an aqueous suspension, wherein the content of the hydrophobic cationic polymer in the aqueous suspension is 1 to 20% by mass, and using the aqueous suspension as the hydrophobic cationic polymer to be added in the step of adding the phenolic resin, the hydrophobic cationic polymer and the clay mineral.

29. The method for treating circulating water in a wet painting room according to claim 24, wherein: The phenolic resin is a phenolic resin before cross-linking and curing.

30. The method for treating circulating water in a wet painting room according to claim 24 or 29, wherein: The weight average molecular weight of the phenolic resin is 100 to 1000.

31. The method for treating circulating water in a wet painting room according to claim 24, wherein: The hydrophobic cationic polymer is a polymer having a cationic structural unit derived from a quaternary ammonium salt of a (meth)acrylate, and a benzyl group is bonded to a nitrogen atom of the quaternary ammonium salt.

32. The method for treating circulating water in a wet painting room according to claim 24 or 31, wherein: The weight average molecular weight of the hydrophobic cationic polymer is 9 million to 11 million.

33. The method for treating circulating water in a wet painting room according to claim 24, wherein: The clay mineral is hectorite.

34. The method for treating circulating water in a wet painting room according to claim 33, wherein: The hectorite is Na 0.3 (Mg,Li)3Si4O 10 Hectorite is represented by (OH)2 and has a negative charge when prepared as an aqueous suspension.

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