US2348625A - Method for the recovery of sprayed paint material - Google Patents

Description

Patented May 9, 1944 METHOD FOR THE RECOVERY OF SPRAYED PAINT MATERIAL Harry E. Hoffman, Mansfield, Ohio No Drawing. Application July 6, 1939,

Serial N0. 283,079

6 Claims. (Cl. 106-287) The present invention relates to a method for the recovery of waste sprayed paint material and more particularly to a new and useful method for the recovery of excess sprayed enamel material from surfaces other than those purposely coated.

It has been the practice heretofore to spray surfaces with paint or enamel by placing paper or other sheet material on the surfaces adjacent to that to be paint sprayed so as to permit application of the enamel or'paint' with sharp edges or lines at the limits of the area to be covered. The method of spraying objects or surfaces with enamel or paint by the use of screens or shields behind the object has also been used to a considerable extent.

Generally the paper employed in the paint spraying operation has beendiscarded. and the screens or shields are usually washed with a suitable solvent to remove the excess enamel or paint which is then thrown to waste.

I have discovered that the waste enamel or excess deposited spray may be recovered in a manner which is rapid, efficient and economical and that the material obtained in the recovery process may be directly used in the paint material without isolating the pigment or vehicle associated with the pigment in the original material sprayed. The product may be readily used by applying the material to the surface to be painted by means of a brush, and if desired the material may be readily purified to such an extent that it may be employed again for spraying in the same manner as the original material.

a The preferred method of carrying out my invention is as follows, although it will be understood that I do not desire to be limited to the specific method as described in detail, except as defined in the claims annexed hereto:

The excess or waste enamel which has been applied to paper or to a metal or other surface is first treated with water before the material has had an opportunity to harden so as to remove substantially all of the enamel, including the pigment and the non-volatile vehicle associated with it. If the enamel is to be recovered from paper. for example, the entire paper mass with the paint material thereon may be soaked for a sufllcient time in water to soften and dislodge the coating material. Then the mass may be strained so as to filter off the paint material from the paper mass. If the enamel to be recovered has been deposited upon a metal surface, the surface may be washed with water which may be sprayed or pumped onto the surface so as to remove the adhering paint material which may be passed into a sump or container from which the 'water may be withdrawn after the sludge or paint mass has been allowed to settle. It will be understood that if water is sprayed onto the metal sheet or surface, the relative amounts are so large that it becomes necessary for purposes of economy to use the water over and over by recirculating and reusing for the successive surfaces to be cleaned, as otherwise the cost of recovery of the excess or waste enamel becomes excessive.

From whatever source the enamel or paint material is derived by means of the water treatment, the material is allowed to settle for a sufficient time so that the enamel or paint material forms a pasty mass at the bottom of the container in which it is allowed to settle and the water gradually separates and comes to the upper surface, forming a layer at the upper portion of the container. The supernatant layer may be drawn off or decanted, tp be used over again, if desired. or the water may be discarded, provided that the amount is not excessive.

The enamel or paint material is then placed in a tank or receptacle in which it may be heated. A tank provided with a water bath is preferably employed so that the temperature may be controlled, providing the desired amount of heat. The water bath is preferably maintained at the boiling point of water, by which the enamel is rapidly softened to such an extent that it may be poured from the tank into other containers.

The softened enamel or paint material is then mixed with a petroleum distillate vaporising more readily than kerosene and less readily than.hightest gasoline, such as Vamolene,'which is a mineral oil distillate having greater volatility than kerosene and evaporating less readily than hightest gasoline. It may be defined as a petroleum fraction substantially free from aromatic hydrocarbons and containing not over 2 per cent of unsaturated hydrocarbons, the said fraction having an initial boiling point between 300 F. and 310 F., a dry point between 400 F. and 415 F., a flash point between .105 F. and F., a fire point between F. and F., and a gravity between 49 B. and 50 B. I have discovered that this mineral oil fraction has a very high solvent power for the partially dried vehicle associated with the ordinary enamel as manufactured at the present time and serves also as a vehicle in the application of the recovered material and volatilizes at a rate so as not to produce pin holes or cavities in the surface after the paint material is applied.

It will be understood that many of the cheaper paints employ volatile solvents or thinners usually low-boilinghydrocarbons, in place of turpentine, to serve as a thinner to assist in the application of the paint by means of a brush. without causing too much "drag" on the brush, but such materials, and in fact substantially all thinners on the market produce a deleterious effect in the application of the paint or enamel, by the production of blow-holes.

The commercial Varnolene has, I have discovered, solvent properties and spreading properties when admixed with waste or deposited enamels which is not possessed by gasoline, gasoline mixtures with other mineral oil distillates or other numerous solvents now on the market.

The proportions of the enamel or paint sludge to Varnolene which I preferably employ are in the ratio of 5 gals. of sludge to from 2 to 2 /2 gals. of Varnlene" although the ratio may be varied outside of these limits and results which are wholly satisfactory obtained.

The mixture of sludge and "Varnolene" is stirred until a homogeneous mixture is obtained, the time generally required being about one hour, with batches of about 5 to 40 gallons of the sludge treated.

After a homogeneous mass is obtained, the material is preferably filtered or screened to remove undispersed masses or foreign solids which would otherwise produce specks or defects in the painted surface. I

After the material is filtered it is ready for use, but it is to be understood that the composition may be varied to some extent, depending upon the use to which the paint is to be put. If it is to be used for outside work, a small proportion of linseed oil may be added, such as one quart to the gallon of the product, and a small proportion of thinner, preferably turpentine, may be added. For inside work, the product may be thinned with a small proportion of Varnolene" although it will be understood that when the material is to be made for this specific purpose, a proportionately larger proportion of Varnolene may be used in the method as above described.

Havingthus described the invention, what is claimed as new is:

l. A method for the recovery of excess sprayed enamel paint material which comprises subjecting the excess sprayed enamel paint material to treatment with water to form a sludge containing pigment and the associated vehicle, heating the said sludge until it is softened sufficiently to readily flow, mixing the heated sludge with Varnolene, stirring the said mixture sufilciently to form a relatively homogeneous mass containing only a small proportion of undesired, undi tributed solid masses and separating the said un esired masses from the admixture.

2. A method for the recovery of excess sprayed paint material which comprises subjecting the said paint material to treatment with water, thus forming a sludge, removing the said water from the sludge, heating the sludge to render it soft so as to readily flow, mixing the heated sludge with a petroleum distillate vaporizing more readily than kerosene and less readily than high test gasoline and corresponding substantially to Varnolene, stirring the admixture to form a relatively homogeneous mass and filtering the mass to remove undesired solid particles therefrom.

3. A method for the recovery of excess sprayed enamel paint material obtained during the process of enamel spray painting, which comprises subjecting the excess enamel material to treatment with water to form a sludge, allowing the sludge to settle, removing the water from the enamel material, heating the sludge to substantially the temperature of boiling water, pouring the heated sludge into Varnolene," mixing the sludge with the "Varnolene" to obtain a substantially homogeneous admixture, and screening the admixture to remove lumps or other undesiredsolid rrlaterial therefrom.

4. A method for the recovery of excess sprayed enamel material from surfaces other than those purposely coated which comprises subjecting the excess enamel material to the treatment with water to remove the same from surfaces on which the spray is not desired, allowing the water enamel mixture to stand to permit the enamel sludge to settle, removing the water therefrom by decantation, heating the sludge to a temperature at which the sludge may readily flow, admixing the sludge in the proportion of five gallons of sludge with from two to two and one half gallons of Varnolene," stirring the admixture to obtain a homogeneous mass and removing undesired solids therefrom by filtering through a series of screens, resulting in a paint material which may be applied to surfaces to be painted by means of brushing or p aying.

5. A method for the recovery of excess sprayed paint material which comprises subjecting they said paint material to treatment with water to form a sludge, removing water from the sludge, heating the sludge to render it soft so as to readily flow, mixing the heated sludge with a petroleum distillate vaporising more readily than kerosene and less readily than high test gasoline, agitatingthe admixture to form a relatively homogeneous composition and removing undesired solid material therefrom.

6. A method for the recovery of excess sprayed paint material which comprises subjecting the said paint material to treatment with water to form a sludge, heating the sludge to render it soft so as to readily flo mixing the heated sludge with a petroleum distillate vaporizing more readily than kerosene and less readily than high-test gasoline, agitating the admixture to form a relatively homogeneous composition and removing undesired solid material therefrom.

HARRY E. HOFFMAN.