JPH0370780A - Treating agent for wet spray booth - Google Patents

Abstract

PURPOSE:To obtain the subject treating agent reducing tackiness of paint in washing water sprayed for collecting surplus paint and inhibiting adhering and solidifying of paint having excellent non-adhesive effect of paint and solid- liquid separating effect in wide range of pH containing a phenolic resin. CONSTITUTION:The objective treating agent contains a phenolic resin [preferably novolak-type phenolic resin (molecular weight: <=1000) expressed by formula I ((n<10; (m)<0.5) or a resol-type phenolic resin (molecular weight: 100-300) expressed by formula II ((n) is 1-3) or formula III ((m) is 0-2)].

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wet spray booth treatment agent, and in particular to a wet spray booth treatment agent for treating the tackiness of paint in wash water that is sprayed to collect excess paint. This invention relates to a wet spray booth treatment agent that reduces adhesiveness and prevents paint from sticking and solidifying inside the system.

[Prior Art] In the painting process in the automobile industry, the yield of paint sprayed onto general car bodies is 60-80%, and 40-20% of the paint used is excess paint that must be removed in the next process. In order to collect this excessively sprayed excess paint, it is usually treated in a wet spray booth by washing with water, and the washing water is recycled.

In such wet spray booths, the excess paint collected in the flushing water is highly adhesive, so it adheres to the spray booth water plate, piping system, spray nozzles, etc., causing clogging of the piping and nozzles. This will significantly reduce the water washing efficiency. Additionally, if the exhaust system of the spray booth is clogged due to excess paint and air circulation is obstructed, the booth will be filled with paint solvent, creating a safety and health hazard and significantly deteriorating the work environment. . Furthermore, most of the surplus paint is deposited at the bottom of the booth pit and circulation bit of the spray booth, and the deposited paint solidifies into a rubbery state over time, requiring a great deal of time and effort to clean and remove.

In order to solve these problems, spray booth treatment agents that are mixed into the cleaning water have been developed, including: ■ Alkali such as NaOH and KOH ■ Amphoteric metals such as Zn salt ■ Cationic polymer ■ Surface activity A method is known in which a chemical agent such as a chemical agent is added alone or in combination with 2 ffi or more to the cleaning water. Others: ■ Melamine-aldehydic acid colloid (Special Publication No. 63-33799
) has also been proposed.

[Problems to be Solved by the Invention] However, among the above-mentioned conventional processing agents, the processing agents (1) to (2) do not have sufficient effects.

(2) The usable pH range is narrow, making it difficult to carry out stable treatment, and requiring a large amount of pH adjuster.

■ Due to drug release &: cOD increases.

■ There are limited types of paints that can be applied, including acrylic paints,
Less effective against phthalate paints.

■ Paint sludge increases when metal salts are used.

It had the following problems and could not be said to be industrially advantageous.

In addition, the following problems were encountered with ① Melanaldehydic acid colloid.

(+) If the circulating water is concentrated due to the acids it contains,
That is, if the washing water is not renewed, the pH tends to decrease. Therefore, the possibility of corrosion of the iron material within the system cannot be denied.

(ii) Regular blowing of circulating water is required.

The present invention solves the above-mentioned conventional problems, has excellent paint non-sticking effects and solid-liquid separation effects, can be used in a wide pH range, generates little sludge, and improves the pH of the system.
The purpose of the present invention is to provide a wet spray booth treatment agent that does not lower the quality.

[Means for Solving the Problems] The wet spray booth treatment agent of the present invention is characterized by containing a phenolic resin.

The present invention will be explained in detail below.

The phenolic resin which is an active ingredient of the wet spray booth treatment agent of the present invention is a condensate of phenol such as phenol, cresol, xylenol, etc. and an aldehyde such as formaldehyde, or a modified product thereof, Examples include phenolic resins before crosslinking and curing. Specifically, the following can be mentioned.

■ Condensate of phenol and formyldehyde ■ Condensate of cresol and formaldehyde ■ Condensate of xylenol and formaldehyde ■ Alkyl-modified phenol resin obtained by alkylating the phenols of ■ to ■ above These phenolic resins are novolacs. The novolac type phenol resin or the resol type phenol resin may be a type or a resol type, and those represented by the following general formula are suitable as the novolac type phenol resin or the resol type phenol resin.

[A] Novolac type phenolic resin (molecular weight: 10
00 or less) (in the formula, n<10.m<0.5) [B] Resol type phenolic resin (molecular weight: 100-300) nμ (in the formula, m=o-2) Such a phenolic resin is Since it is poorly soluble in water, it is preferable to use it in the form of a solution or emulsion by dissolving or dispersing it in a water-soluble solvent. Examples of solvents used include ketones such as acetone, esters such as methyl acetate, methanol, etc. Examples include water-soluble organic solvents such as alcohol, aqueous alkali solutions, and amines. Usually, an aqueous alkaline solution such as NaOH or KOH of about 0.1 to 50% by weight is used.

The amount of these solvents to be used is not particularly limited as long as the phenolic resin is sufficiently dissolved.

For example, when using an alkaline aqueous solution such as NaOH, the weight of NaOH relative to the phenolic resin should be 0.1% or more, usually 1 to 100%. NaOH
However, if 0.1% by weight of the phenolic resin is not mixed, undissolved components remain, which is not preferable.

Next, a method of using the wet spray booth treatment agent of the present invention will be explained.

The treatment agent of the present invention is injected into the circulating cleaning water of a wet spray booth to make the excess paint collected in the cleaning water non-adhesive, prevent it from adhering to the water film plate and piping, and also to prevent it from adhering to the water film plate or piping. This prevents the sludge deposited on the surface from becoming sticky and solidifying.

The addition amount of the processing agent of the present invention is suitably in the range of 0.01 to 100%, usually in the range of o, i to 10%, based on the weight of the phenolic resin based on the amount of excess paint. The amount of injection into the circulating water varies depending on the amount of paint applied, the coating method, etc., but the concentration of phenolic resin in the circulating water is 0.1 to 50.
A rough guideline is about 0 ppm, and it is appropriately determined by a spray test as shown in the Examples of the present application.

The method of adding the treatment agent of the present invention is usually continuous injection depending on the amount of paint sprayed, but intermittent injection may also be used.

There are no particular restrictions on where the treatment agent can be added, but it is most effective to add it to the circulating water supply side, especially to the piping system just before the cleaning water and paint come into contact.

Since the treatment agent of the present invention works effectively at a pH of 10 or less, for example in the pH range of 7 to 10, there is no need to particularly adjust the pH. However, if the pH in the system is lower than neutral for some reason, from a corrosion prevention perspective Adding an alkaline agent, conversely, increases the p in the system.
If the H content is extremely high, the pH is adjusted by adding an acid to ensure the stability of the effect. As the acid or alkali agent used for pH adjustment, known ones such as hydrochloric acid, nitric acid, sodium hydroxide, potassium hydroxide, etc. can be selected.

By adding the wet spray booth treatment agent of the present invention, excess paint in the washing water becomes tack-free. Since the paint particles that have become tack-free can be easily separated into solid and liquid, by separating them, the separated water can be reused as rinsing water.

Although there are no particular limitations on the means for separating paint particles in the used wash water discharged from the booth, flotation separation or physical solid-liquid separation means may be employed. Specific examples of the physical solid-liquid separation means include wedge wires, rotary screens, bar screens, and cyclones.

The sludge recovered by the solid-liquid treatment can be dehydrated by gravity or by a conventional dehydrator, and then disposed of by incineration, landfill, or the like.

In addition, by using the treatment agent of the present invention, the stickiness of excess paint etc. collected in the washing water is sufficiently improved, so there is no need to use other flocculants during solid-liquid separation. , it is possible to perform effective solid-liquid separation, but in order to increase cohesion and perform separation more reliably and efficiently,
It is preferable to coarsen the floc using an inorganic flocculant or an organic polymer@flocculant. Particularly when flotation separation means is employed as the separation means, it is advantageous to use a flocculant.

As an inorganic flocculant, PAC (polyaluminum chloride)
, sulfuric acid, ferric chloride, etc. can be used.

Examples of organic polymer flocculants include polyethylene oxide,
Nonionic polymer flocculants such as poly(meth)acrylic acid, methyl cellulose, urea-formalin resin, poly(
Meth)acrylates, partial hydrolysates of poly(meth)acrylic acid, anionic polymer flocculants such as polystyrene sulfonates, polydiallyl quaternary ammonium salts, poly(meth)acrylic acid acinoesters, polyalkylenes Polyamines such as polyethicine, polyamide polyamine, dihaloalkane polyamine polycondensate, Mannich modified polyacrylamide, Hofmann decomposition product of polyacrylic acid, boria-based noalkyl (meth)acrylate, polyvinylpyridium halide, poly(meth) Examples include cationic polymer flocculants such as acrylate polyalkyleneboriane, cationized starch, chitosan, polyvinylimidacin, and water-soluble copolymers thereof. Other examples include copolymers of acrylamide or methacrylamide with other vinyl monomers such as acrylic esters, acrylonitrile, dialkyl aryonoethyl methacrylate or quaternized products thereof, water-soluble dicyandiamide-formaldehyde condensates, polydimethyl diallylammonium Salts, shrimp halohydrin-amine condensates, cationized guar gums, etc. can also be used.

These flocculants can be used alone or in combination of two or more.

These flocculants are preferably added immediately before the separation means, and in this case, it is advantageous to provide a suitable reaction tank because flocculation can proceed more easily. Also,
The amount added is 0.001 by weight relative to excess paint.
~100%, usually in the range of 0.01 to 50%, and when injected into circulating washing water, it varies depending on the amount of excess paint in the water, but 0.01 to IQOOPPm.

Usually, it is preferably in the range of 0.05 to 1100 pp, and the optimum amount to be added is generally determined as appropriate by a jar test.

In the present invention, surfactants that may be used in combination to improve the dispersibility and emulsification of the paint in circulating water include any known anionic surfactants, non-ionic surfactants, and One type or a combination of two or more types of ionic surfactants, zwitterionic surfactants, or cationic surfactants can be used. Specifically, sodium alkylbenzenesulfonate, sodium higher alcohol sulfate, sodium alkylsulfate, sodium alkylsulfonate, sodium alkylsulfosuccinate, sodium dialkylsulfosuccinate, sodium alkylnaphthalenesulfonate-formalin condensate, alkylnaphthalenesulfonic acid. Anionic surfactants such as sodium, sulfonated heterocyclic compounds, fatty acid-amino acid condensates; polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyethylene glycol fatty acid ester, polyoxyethylene fatty acid amide ether, polyethylene glycol alkyl Nonionic surfactants such as amine ethers, polyhydric alcohol fatty acid esters, polyoxyethylene polyhydric alcohol fatty acid esters, and alkylolamide; amphoteric surfactants of betaine type, imidacillin type, sulfonic acid type, or alanine type: alkyl pyridine Examples include cationic surfactants such as sodium hydrochloride, alkyltrimethylammonium halide, polyoxyethylene alkylamine, and polyoxyethylene dodecylamine. In the present invention,
Among these surfactants, it is preferable to use nonionic surfactants.

The amount of surfactant used is 1 to 1 for the phenolic resin.
00% by weight is appropriate.

In the present invention, by using a carboxylic acid or a carboxylic acid salt together with a phenolic resin, it is possible to further improve the non-tackiness of the paint.

As the carboxylic acid to be used, hydrophobic group-containing carboxylic acids or salts thereof which are insoluble or poorly soluble in water are effective, and the following carboxylic acids or salts thereof may be mentioned.

■ Alkali-soluble saturated or unsaturated fatty acids with 5 or more carbon atoms.

For example, hexanoic acid, valeric acid, lauric acid, pallic acid, oleic acid.

■ Alkali-soluble dibasic acid with 5 or more carbon atoms.

For example, heptaniic acid, dodecanniic acid, glutaric acid, adipic acid, sebacic acid.

■ Benzoic acid or its alkyl derivative.

These carboxylic acids can be used, for example, as follows.

■ A carboxylic acid dissolved in an alkali (including amine) is injected separately or simultaneously with the phenolic resin.

■ Phenolic resin and carboxylic acid are simultaneously treated with alkali (
(including amines) and injected.

The amount of carboxylic acid used is 0.00 based on the amount of excess paint.
The preferred range is 1 to 100% by weight, usually 0.01 to iog%.

[Function] The phenolic resin dissolved in colloidal form in an alkaline aqueous solution is added to the circulating water and the pH drops to a neutral range, causing the colloidal nature to be broken and the resin to associate. , combined with paint ingredients mixed in,
Insolubilize. The combined body containing this paint component exhibits strong phenolic resin properties, which removes the stickiness of the paint. Moreover, since this combined body aggregates into flocs of a certain size, the solid-liquid separability is greatly improved and it can be easily separated and recovered using a bit. Therefore, the clarity of the circulating water is maintained.

When a carboxylic acid is used in combination, the carboxylic acid dissolved in the alkaline solution becomes insolubilized as the pH decreases in the circulating water. Then, the insolubilized carboxylic acid binds to the surface of the paint particles together with the precipitated phenolic resin, further enhancing the non-tackiness.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 Using the testing apparatus shown in FIG. 1, the effects of various drugs were tested.

In FIG. 1, 1 is a bit, 2 is a water film plate, 3 is a circulating water pipe provided with a circulating water pump P, 4 is an exhaust pipe provided with an exhaust fan 4A, and W is a water surface. 5 is water film plate 2 of bit 1
This is a spray gun installed above for spraying paint.

This test device has a holding water volume of 501, and a circulating water volume of 3011.
/min. The washing water used was one in which the chemicals shown in Table 1 were added in the amounts shown in Table 's1, and the pH was adjusted to 7 to 10. In Table 1, the phenolic resins used and the solvents used to dissolve them are as follows.

Regitop PSM-4228: Phenol/formalin condensate (novolac type) Regitop PSF-4812: Cresol/formalin condensate (novolac type) Regitop PS-2852: Alkylphenol/formalin condensate (Novolak type) (All manufactured by Gunei Chemical Industry ■) Note: Alkalini 5% by weight NaOH aqueous solution Ayo: 301i% dimethylaminoethanol aqueous solution Ester: Ethyl acetate The test was performed using 50 cc of amino alkyd resin paint ( Engineering≧−
Rack 050-1205, made by Rock Paint) 1
After spraying from the spray gun 5 at a speed of 0 cc/min,
This was done by observing the appearance of the sprayed paint, washing water (circulating water), bits, piping, etc. From this observation result, depending on the amount of paint attached to the inner wall of the bit and piping,
Adhesiveness was evaluated based on the following criteria. The results are shown in Table yg1.

4.1 ×...Same as the adhesion status of raw paint.

Δ...The amount of adhesion is slightly lower than that of raw paint.

○...Almost no adhesion.

O...Does not stick.

From the above results, it is clear that the wet spray booth treatment agent of the present invention can reduce the amount of adhering paint by adding a small amount, and can significantly reduce adhesion and adhesive solidification of paint inside the system in wet booths. .

[Effects of the Invention] As detailed above, the wet spray booth treatment agent of the present invention has (1) an excellent effect of making paint tack-free;

■ Good solid-liquid separation effect.

■ Effective in a wide pH range.

■ Does not lower pH. Moreover, when used after being dissolved in an alkali, it also exhibits an anticorrosion effect.

■ Since it is not an inorganic metal salt, there are fewer sludge precepts.

It is possible to effectively reduce the stickiness of the collected surplus paint and make the paint into a free-flowing particulate form that can be easily removed.

Therefore, according to the treatment agent of the present invention, (1) clogging of nozzles due to adhesion of paint to pipes etc. is prevented, water washing efficiency is maintained at a good level, and maintenance is reduced.

■ Deterioration of the working environment due to blockage of the exhaust system is prevented.

■ Paint sludge deposited or floating on booth bits, etc. becomes difficult to solidify and can be easily removed. Therefore, the removal work is reduced.

■ Washing waste liquid becomes easier to separate into solid and liquid, making wastewater treatment easier.

■ Solids in used washing water can be separated and removed with high separation efficiency, and the clarity of wI ring water ice water can be maintained at a high level.

This effect is also achieved, making it possible to carry out painting booth treatment industrially very advantageously.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the test apparatus used in Example 1. 1...Bit, 2...Water film plate, 5...Spray gun.

Claims (1)

[Claims] (1) A wet spray booth treatment agent characterized by containing a phenolic resin.