US1695430A - Agent for cleaning and imparting rust-inhibitive properties to steel - Google Patents

Description

I Patented Dec-618,128. I i *UNITED'STATES PATENT OFFICE.

nuns n.'xr.i1venn,'or Damon, moment;

No Drawing.

My invention relates to an improved method of cleaning and preparing steel for painting. The ob ectis to provide an improved method and agent through the use of which steel may be cleaned and rust resisting properties imparted hereto.

This invention is particularly valuable in 4 connection with the preparation of the sheet erties thereto.

steel employed in the manufacture of automobile bodies. The grease, dirt, oil, rust, etc., must be cleaned from this sheet steel and the surface prepared to receive the priming coat of paint. To meet this commercial demand, itis essential that the method, and agent em: ployed therein, be inexpensive, and that the process be a rapid one. By following my improved process the steel is thoroughly cleaned so as to receive and retain. the priming coat of paint and the surface of. the metal is rendered substantially immune to the subsequent action of rust.

' I provide a suitable cleaning solution which is applied as a wash or a bath to the metal to be treated to remove the grease, oil, dirt,

: rust, etc. For this purpose I prefer to employ a solution composedof an effective rust attacking and removing acid, such as sulfuric acid, and a solvent for. the oil, grease, etc., suchas alcohol or acetone. Denatured alcohol containing a small percentage of acetone makes a very satisfactory solvent. j

I have found that by using a cleaning solution such as above containing as an added ingredient, a suitable 'hydroxycarboxylio acid, that rust inhibitive properties willbe imparted to the surface of the metal. The hydroxycarboxylic acid in the solution acts upon the metal and prevents the formation of iron hydroxide, which is the first stage of rust, and which otherwise would occur as a. result of the presence of the sulfuric acid'and the water. I prefer to employ in this connection a hy-. droxytricarboxylic acid, of which the most common one is citric acid. However, hydroxydicarboxylic acid, such as tartaric acid is effective for the purpose.

Generally stated, this invention consists in applying a fluid admixture of a hydroxycarboxylic acid, a rust attacking and removing acid and a solvent for oil and grease to the steel to be treated, which solution removes all oil, grease, dirt, rust, etc., from the surface of the material and gives it a bright, clean finish, prevents the formation of iron hydroxide thereon, and imparts rust resisting prop- Application filed June 27,

. ingredients in substantially Aomir ron CLEARING- AND mrAm-me nUsr-INHIBIrIvE' rnornn'rms r0 srmam.

1924. Serialflo. 722,720.

The cleaning solution may be applied to the metal by painting or spraying the metal therewith. A period from two to three minutes should be allowed for the solution to act. In cases where there is deep-seated rust on the steel the cleaning'solution and the resultant products of the cleaning action are washed from the steel byrinsing with hot or cold water. If cold Water is used, it should be flowed on freely and thewater remaining on the steel blown ofi' with air. If hot water is used any water that has not evaporated should be blown off with air. .The water should be completely removed from the surface of the metal and'it may be necessary to torch ofi' around mouldings or pockets with a gas flame to drive out the remaining water. I The steel should then be saturated with turpentine or alcohol andplaced in a pre-heat oven to dry. The steel is now ready to receive the priming coatrof paint.

The strength of the solution and the proportion of the respective ingredients may be varied to meet the exigencies of the. material vto be cleaned. I have found, however, that a solution comprising sulfuric acid, citric acid and denatured alcohol having a small per.- centage of acetone is particularly effective, and, a very satisfactory strength is to provide these ingredients in the proportion, byvolume, of-thirty-five parts of an aqueous solution 'of citric acid (strength of solution twenty per cent), five parts of concentrated sulfuric acid, fifty parts of denaturedalcohol and ten parts of acetone.

What I claim is:

1. A solutionto be used in the cleaning of steel and the imparting of rust inhibitive properties thereto containin he approximate volume of five parts of alcohol,four parts of citric acid and one part of sulfuric acid.

2. A solution to be used in the cleaning of steel and the imparting of rust inhibitive properties theretocontaining the following wiped with a cloth 7 the following imparting rust resisting properties to st'e'el containing a solvent for grease and oil, a rust removing acid and a hydroxycarboxylic? acid. L

A solution to be used for cleaning and imparting rust resisting properties to steel 6. A. solution to be used for cleaning and containing denatured alcohol, an aqueous soimparting rust resistingproperties to steel lution of citric acid, sulfuric acid and a small containing a hydroxytricarboxylic acid. 1o

6 5. A solution to be used for cleaning and tion.

imparting rust resistin properties to steel I containing a hydroxycar oxylic acid. JAMES D. KLINGER.

percentage of acetone. In testimony whereof, I sign this specifica-