US2009357A - Varnish and lacquer remover - Google Patents

Description

speed on coatings Patented July 1935 PATENT OFFICE 2,009,357 VARNISH AND LACQUER REMOVEB Carleton Ellis, Montclair, N.

Chadeloid Chemical N. Y., a corporation of West J., assignor to Company, New- York,

Virginia No Drawing. Application March 2'7, 1931, Serial 3 Claims. (01. 87-5) This invention relates to a remover for softening finish coatings such as those of paint, varnish and lacquer and relates particularly to finish removers possessing a high cutting or softening which are to be removed and also which in the preferred form is substantially free from the objectionable dripping qualities possessed by many so-called liquid removers.

The solvent portion of the remover. is composed of volatile liquid solvents such as acetone and other ketones, methyl and ethyl alcohol and similar alcohols, including secondary alcohols such as isopropyl alcohol. Incorporated with such solvents I preferably employ a hydrocarbon solvent which for some purposes may be benzol or other hydrocarbons of as toluol and solvent naptha. Preferably, however, I employ a hydrocarbon solvent from petroleum in order primarily to avoid the stigma attached to benzol solvent because of its alleged toxic properties. A gasoline or naptha made by the hydrogenation process is suitable for the purpose, preferably one high in naphthenes.

Mixtures of these solvents may vary a good deal but for the uses of the preferred invention should have a low content of any solid material such as wax used to prevent or retard evaporation.

Waxes of the type of paraffin or ceresin are preferred; such mineral waxes having a rather special film-forming quality which makes them highly desirable for the purpose.

As a thickening agent nitrocellulose or celluloid may be used'and has in fact been used to a considerable extent. Two or three per cent suflice to give a certain amount of body to the thin highly flowable liquids used and at the same time help to keep the wax in better condition for the purpose of readily forming a thin superficial film that retards evaporation. However, the thickening action of the nitrocellulose is pervasive, that is, it extends through the entire liquid in such a way that the increase in viscosity reduces penetration and for that reason the rate of softening or cutting of the coating to be removed is reduced. Hence the removers containing nitrocellulose have not been nearly as popular as those which are made without a thickening agent of this character but containing just enough paraflin wax to retard evaporation. A common mixture for this purpose has been 50 to 60 per cent of benzol, the balance of the liquid-portion being acetone, methanol, ethanol and the like, in which has been incorporated about 3 per cent-of wax. Such a liquid remover while relatively active has a dripping qualitywhich is objectionable. When the aromatic series, such for example as may applied to a vertical surface the composition runs frequently when the surface is the wall of a 'room, running down on to, the floor.

The addition of nitrocellulose stops the dripping action but, as stated, retards the cutting speed to some extent.

In the present removing composition I employ an anti-dripping agent which does not reduce the cutting speed. This anti-dripping agent is a metallic soap of the water insoluble type freequently called metallic soaps". Among these soaps I prefer those of the heavy metal such as lead or. cadmium, preferably the latter, and as the fatty acid component I prefer a liquid fatty acid, such as oleic acid, although I may use mix- 5 tures of oleic and palmitic acid or stearic acid or sometimes may employ lauric acid in place of or admixed with oleic acid. In any event the compound preferably is made from higher fatty acids of the oil acid type, that is the glyceride acids. In some cases I may inter-react naphthenic acid (forming a more complex-metal soap) From whichever fatty acid or fatty acid mixture used the metallic soap may usually be readily made'by reacting moist freshly-precipitated hydroxide, such'as cadmium hydroxide, and the fatty acid, e. g., oleic acid. These may be combined by heating gradually with stirring up to a temperature of about 120 to 130 C. The proportion of cadmium hydroxide to oleic acid may be 3 one mole of the former to two moles of the acid. To incorporate the components of the remover I may for example dissolve the paraffin wax and the cadmium oleate in the gasoline or other hydrocarbon solvent heating it necessary for the purpose of melt g the wax and cadmium oleate together and adding the molten material to the gasoline. when this is in solution the mixture is added to the other solvents preferably with stirrin 40 With reference to the other solvents of the softening type my preference is to employ a mixture of lsopropyl alcohol and acetone,- such be obtained by passing isopropyl alcohol through a heated tube, the temperature being raised to the cracking point and the exposure of the isopropyl alcohol being prolonged until amoroi iimately three-fourths of it is converted into acetone. By employing isopropyl alcohol of a grade which contains not more than one or two percent of water and preferably isopropyl alcohol which isanhydrous, the resulting mixture of one-fourth isopropyl alcohol and three-fourths acetone will not contaln enough water to be harmful. However,

" scrap and 8 pounds and more than a few per cent of water greatly reduces the cutting activity of the remover and water therefore should be a'voided in making a rapid working removing composition.

In order to reduce the wax content to a minimum I prefer to employ a major proportion of the cracked isopropyl alcohol as the mixture of isopropyl alcohol and acetone may be termed. By having present a minor proportion, say 30 to 40 percent by volume of the hydrocarbon solvent, the amount of wax requiredis diminished from that necessary when the hydrocarbon solvent is the major component. Very good proportions are 30 gallons of the hydrogenated gasoline to 10 gallons of the cracked isopropyl alcohol which is about three-fourths converted into acetone. Using this solvent mixture I may incorporate in any suitable way, for example as indicated above, 16 pounds of paraflin wax of 133 F. melting point and about 8 pounds of cadmium oleate. In another case I have used the proportion of 8 pounds of wax to about 16 pounds of cadmium oleate;

While I have referred to nitrocellulose in the foregoing with respect to its retarding action on the cutting rate, I do not wish to be precluded from introducing celluloid or nitrocellulose-into such compositions as have been described. For

example, using the solvent ratioof 70 to 30 as specified, I may employ in 100 gallons of such solvent mixture 8 pounds and 5 ounces of paraffin wax, 16 pounds and 11 ounces of celluloid 5 ounces of cadmium oleate. a

In some cases even I may omit the wax using cadmium oleate or equivalent component and nitrocellulose. For example, in a volume of solvent mixture, indicated in proportions as above, 25 pounds of celluloid scrap and 8 pounds and 5 ounces of cadmium oleate are introduced.

removing composition of this character, being wax free, is less inclined to be a hazard with regard to subsequent coats of finish. If an operator is careless and does not wash oil wax completely from the surface when using a waxy bodied remover, there is danger that the subsequent coat may be affected. Using nitrocellulose and cadmium oleate I reduce this danger or reduce the wax hazard.

The employment of the petroleum naphtha with the cracked isopropyl alcohol avoids the introduction into the remover of solvents which have been frequently used in the past, namely, benzol and methyl alcohol, both of which have been under surveillance with respect to their hygienic qualities when used in confined spaces. The composition of the present invention therefore provides a remover tree from these solvents when so desired.

From the foregoing it will be evident that the solvent composition of the removermay be greatly varied and that the solid components or thickening or film forming agents or anti-dripping agents likewise may be varied through a wide range of proportions, depending upon.the precise result desired. While I mention cadmium oleate in an illustrative way, I do not wish to impose any limitation thereby. Thus aluminum pmmitate may be used to good advantage and usually in lesser proportion than the cadmium oleate. The low specific gravity of aluminum palmitate is also in its favor. Aluminum oleate is not as effective as aluminum palmitate in maintaining the suspension and distribution of the wax not in solution nor is it as good as an antidripping agent. Cadmium oleate and aluminum palmitate both serve most excellently as distributors of the particles of wax not in solution.

What I claimis: v

1. A finish remover having a major proportion of cracked isopropyl alcohol which contains several times more of acetone than of isopropyl alcohol and a minor proportion 01' a petroleum hydrocarbon wax solvent, and containing not more than a minor proportion of wax and a metallic soap. I

2. A finish' remover according to claim 1 in which cracked isopropyl alcohol containing about 75 per cent of acetone is used. V.

3. A finishremover according to claim 1 in which wbstantially anhydrous cracked isopropyl alcohol is used.

CARLETON ELLIS.