JPH0649396A - Water-soluble paint remover - Google Patents

Abstract

PURPOSE:To lower the aging rate of the performance of a water-soluble paint remover itself and prolong the renewal period of the remover to enhance the economy of removal treatment, by incorporating a flocculant into a water-soluble paint remover. CONSTITUTION:The remover contains a flocculant generally used in water treatment and waste water treatment. The flocculant is such as agent as to flocculate substances dissolved or dispersed in an aq. soln. to float up or settle out them for separation thereof. Usable flocculants are broadly divided into inorg. flocculants and org. polymeric flocculants. The amt. of the flocculant to be blended is generally 0.01 to 1.0wt.% based on the water-soluble remover. In the case of an org. polymeric flocculant in particular, when at least 1.0wt.% flocculant is used, the viscosity of the water-soluble paint remover itself is increased to deteriorate flocculation of a coating film removed, while the solubility of the flocculant also becomes unstable unfavorably. When at most 0.01wt.% flocculant is blended, the resulting paint remover is insufficient in flocculation performance unfavorably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film for removing a coating film adhering to a coating tool such as a coating jig or a spray gun, or for re-coating a coating error part or an aged part of the coating film. The present invention relates to a water-soluble paint remover that removes

[0002]

2. Description of the Related Art Conventionally, it is necessary to remove a coating film adhered to a coating tool such as a coating jig or a spray gun, or to remove a coating film for repainting an erroneous coating part or a part with an old coating film. Paint strippers are used as one method. Further, generally, what is called a solvent-type release agent that uses thinner, methylene chloride, phenol, toluene or the like as a solvent to swell and remove the coating film is used. However, many of the solvents used for the solvent-type release agent are highly toxic and highly inflammable, and their use is currently being regulated.

As a measure against such a problem, a water-soluble paint remover has been developed. The water-soluble paint remover is a water-based solvent that is solubilized in a water-soluble solvent or an insoluble solvent, and may further contain alkalis. Generally, a high boiling point solvent such as a polyhydric alcohol or a derivative thereof is used as a solvent.

[0004]

However, when the coating for drying at room temperature or the coating before baking even with the coating for baking is removed by using the water-soluble paint remover, the removed coating is dissolved and Since it is removed in a decomposed state, the removed coating film is in a state of being dissolved and dispersed in the solution of the release agent. As a result, the release agent liquid is thickened, the penetrability of the release agent component into the coating film is deteriorated, and the coating removal ability is reduced. Further, there is a problem that the dispersed coating film is reattached to the object to be treated. This also shortens the liquid renewal period and increases the economic burden.

[0005]

In order to solve the above problems, the present invention provides a water-soluble paint remover characterized by containing a flocculant.

The water-soluble paint remover referred to in the present invention is a known one, which basically contains water as a component, and may contain a water-soluble organic solvent or a water-insoluble organic solvent in addition to water. It is contained by solubilization. Other, alkali, wetting agent,
It is a paint remover that may contain additives such as rust preventives.

Examples of the organic solvent used in the water-soluble paint remover according to the present invention include ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, ethylene glycol butyl ether, diethylene monomethyl ether, diethylene glycol monoethyl ether, Alcohols such as diethylene glycol diethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, solfit, tetrahydrofurfuryl alcohol and diethylene glycol, and derivatives thereof. A polar solvent such as dimethylsulfoxide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, dimethylimidazolidinone, γ-butyl lactone, tetramethylurea, ethylene carbonate, propylene carbonate, diethyl carbonate, morpholine. Alternatively, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, N-methylpropionamide, aminoethylethanolamine, dimethylethanolamine and N-methyldiethanolamine. Further, esters such as ethyl cellosolve acetate, ethyl acetoacetate, methoxybutyl acetate, ethylene diacetate are exemplified.

The coagulant referred to in the present invention generally means water treatment /
It is an aggregating agent used for wastewater treatment, and is an agent for aggregating substances that are dissolved and dispersed in an aqueous solution to float or sediment. It is roughly classified into an inorganic coagulant and an organic polymer coagulant.

Examples of inorganic flocculants include polyaluminum chloride, sulfuric acid band, ferrous sulfate, ferric sulfate, polyiron chloride, copper chloride, ammonia alum, potassium alum, sodium aluminate and the like. .

The organic polymer flocculant may be cationic, anionic or nonionic, and can be used more effectively by appropriately adjusting the pH regardless of ionicity. As the cationic polymer flocculant, polytrimethylammonium ethyl methacrylate, polyethyleneimine, polyacrylamine, polyvinylimidazoline, polyalkylaminoacrylate,
Polyalkylaminomethacrylate, Mannich modified acrylamide, acrylamide-trimethylammoniumethylmethacrylate copolymer, diallylamine-sulfur dioxide copolymer, hexamethylenediamine-
Examples thereof include epichlorohydrin polycondensate.

Examples of the anionic polymer flocculants include sodium alginate, carboxymethyl cellulose, sodium polyacrylate, acrylamide-acrylate copolymer, and partial hydrolyzed polyacrylamide.

Examples of nonionic polymer flocculants include polyacrylamide, polyethylene oxide, guar gum, locust bean gum and the like.

The use of these aggregating agents may be appropriately selected depending on the type of coating material to be used. For example, it can be selected by testing the cohesiveness using a jar tester or the like. Further, an inorganic flocculant and an organic polymer flocculant may be used in combination.

The amount of the aggregating agent to be added is not particularly limited, but is generally 0.1% with respect to the total amount of the water-soluble paint remover.
It is from 01 to 1.0% by weight. In particular, in the case of an organic polymer flocculant, if it is used in an amount of 1.0% by weight or more, the viscosity of the water-soluble paint remover itself becomes high, and the coagulation of the removed coating film becomes poor. Further, the solubility of the aggregating agent becomes unstable, which is not suitable.
Further, if the content is 0.01% by weight or less, sufficient cohesive force cannot be obtained, which is not suitable.

The coagulant may be added to the water-soluble paint remover from the beginning or may be added later. In the case of adding, those having good solubility may be added as they are in the original form, and those which are difficult to dissolve may be dissolved in water or a solvent in advance. As a method of using the water-soluble paint stripping agent of the present invention, a method of immersing an object to be stripped in a water-soluble stripping agent is generally used, but shower, shaking, ultrasonic wave, etc. and a combination of these methods may be used. Good. The type of paint to be peeled off is not limited, and any coagulant capable of coagulating can be used.

The paint which has been dissolved, decomposed and removed is agglomerated by an aggregating agent and precipitates or floats. By appropriately taking the agglomerated paint out of the system, the aging of the stripping solution can be further suppressed. As a take-out method, a conventional method may be used,
For example, the drainage can be taken out or the vacuum can be taken out from the peeling tank.

[0017]

EXAMPLES The present invention will be described below with reference to examples. Examples 1 to 8 Water-soluble paint removers having the formulations shown in Table 1 were prepared and coated with cationic electrodeposition paint and urethane paint (however, not baked) Iron (JIS SS-41)
The test piece of 1 was immersed in each composition (liquid temperature 25 ° C.), and the change in the peeling time (time until the paint was removed) was examined depending on the amount of the removed paint mixed. The results are shown in Tables 2 and 3.

Comparative Examples 1 and 2 The same composition as shown in Table 1 was tested in the same manner as in the above Examples. The results are shown in Tables 2 and 3.

[0019]

[Table 1] (Note) 1) Polyacrylamide type anionic polymer flocculant 2) Polymethacrylate ester type cationic polymer flocculant 3) Polymethacrylate ester type cationic polymer flocculant (average molecular weight 2.5 million) 4) Polyacrylamide Anionic polymer flocculant (average molecular weight 12 million) 5) Polyacrylamide nonionic polymer flocculant (average molecular weight 12 million) 6) Polyacrylamide nonionic polymer flocculant 1), 2), 6) , Sanyo Chemical Industries 3), 4), 5) are manufactured by Kyoritsu Organic Industry Research Institute

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

EFFECTS OF THE INVENTION The water-soluble paint remover according to the present invention causes the dissolved / decomposed coating film to flocculate or float up. Therefore, the aging rate of the release performance of the water-soluble paint remover itself is lowered and the renewal period of the liquid is reduced. It can be made longer and economic efficiency can be improved. Further, since the removed coating film is aggregated, settled or floated, it is easy to take the stripping liquid out of the system, and the waste liquid treatment is facilitated.

Claims (1)

[Claims] 1. A water-soluble paint remover containing a flocculant.