US2062038A - Composition for cleaning and brightening metals - Google Patents

Description

Patented Nov. 24, 1936 UNlTED STATES PATENT orrlcr;-

COMPOSITIONFORCLEANING AND BRIGHTENING METALS Harry B. Rathbun, Waterbury, Conn.

- No Drawing. Application June 10, 1935,

-. 7 Serial No. 25,809

2 Claims. (Cl. 87-5) ing discolorations and stains from the surfaces of metal-articles.

One object of this invention is to provide an improved cleaning preparation of the above na- 19 ture which will produce a durable ,bright surface on the metal preparatory to subsequent lacquerng. plating, or drawing operations.

A further object is to provide a preparation of the above nature which will produce a durable bright surface on a metal article after it has been annealed and pickled. A further object is to provide a cleaning composition of the above nature which may be em 'ployed to facilitate the galvanic deposition of a 20 Protective metal, such as tin, upon the surface of non-ferrous metal articles when they are boiled in an aqueous solution of said composition in the presence of block tin.

A further object isto provide a cleaning and brightening preparation which will be simple and inexpensive to manufacture, non-injurious to the hands of the user, easy to apply, andeflicient in use.

In previous cleaning preparations adapted to be dissolved in water for brightening metal articles, cream of tartar and acid phosphates have been chiefly used as the principal active agents. The former, however, is quite expensive, while the latter is apt to cause the work to become discolored if it remains in the solution for any substantial length of time requiring refinishing. By means of the present invention, a cleaning preparation has been provided which avoids the above and other disadvantages. 40 The chief active ingredient of the new cleaning preparation is phthalic anhydride (or acid phthali'c anhydride) CsH4(CO) 20, which when dissolved in water reacts to form orthophthalic acid or naphthalic acid having the formula CBH4 COOH 1L This acid is very weak in hydrogen ionconcentration, and hence exerts only a slight etching effect upon the metal to be treated. The preparation also includes an inert electrolyte, such as sodium sulphate (NaaSOQ in order to make the cleaningaction more uniform.

For the purpose of saponifying and emulsifying any oily or fatty materials which may be present on the surface of the metal articles, the preparation also includes soap and soap bark,

5 the latter ingredient being an effective foam producer and also known in the trade as Quillaja, China bark", and Saponaria. (The principal constituents of soap bark are quillajic acid, quillaja sapotoxin, and. tannin.)

The invention will be further illustrated by the 5 following typical example: v

For eachflO pounds of the metal articles to be treated, a solution will be made up of the following ingredients: 7 v

, 7 Percent 10 Water lbs 2. Phthalic anhydride oz .08 .25 Sodium sulphate oz .2 .61 Powdered soap "oz-.. .2 .61 Soap bark oz .2 .61 15 The metal articles to be cleaned will be placed in a rotating tumbling barrel, and a sufficient quantity of the aqueous solution will then be 2 added to the tumbling barrel until all of the articlesare completely covered. Or, if desired, the water will first be added to the metal articles in the'tumbling barreljand the dry ingredients will be later dissolved therein. 25

It will be understood that the above example isgiven by way of illustration only, and that the percentages of the ingredients may be varied to some extent within the spirit of the :vention, 0

' depending upon the amount of work to be treated in' the tumbling barrels, and the time required to obtain the desired color or brightness.

One of the desirable features in cleaning preparations for brightening metals is that the active 35 ingredient should dissolve only slightly in water.

The phthalic anhydride preparation according to the present invention meets this requirement because it is a material of low solubility, and in use, acts as a reservoir which will slowly give 40 off acid to the solution as it is used up.

It will be noted that phthalic anhydride has approximately two and one-half times more acid content per unit of weight than cream of tartar and acid phosphates commonly used in such 45 preparations. The present market price of phthalic anhydride is about 10% less than that of cream of tartar, and hence itii vill be seen that phthalic anhydride is far more economical to use. Moreover, even when a part of the phthalic an-- 50 hydride is replaced by a neutralsalt, the'preparation will have approximately the same etching and cleaning action as the full-strength cream of tartar or acid phosphate preparations. It is to 5 be understood that it is within the scope of the present invention to omit the neutral salt from the preparation, as the phthalic anhydride alone, mixed with the soap bark and soap, will also give good results.

It will also be understood that either the soap I bark or soap, or both, may in some cases be omitted from the composition within the scope of the invention.-

A further advantage of the cleaning preparation made according to this invention is that it is non-poisonous, and will not injure the skin in anyway.

The preparation may also be employed to facilitate the coating by electrogalvanic-action of metal articles with tin, and to prevent discoloration of said articles during the process. In operation, seven or eight alternating layers of block tin and the articles to be coated will first be laid in a barrel, preferably of brass-the improved cleaning preparation in dry form being sprinkled on' the top of each layer. Water will, then be added and the contents boiled as long as desired.

While there have been disclosed in this specification two examples in which the invention may secure Letters Patent is:

thereof.

. aoeaose be embodied, it is to be'understood that these examines are shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosures but may be modified and embodied in various other 'i'orms without departing irom its spirit; In short, the invention includes all the modifications and embodiments coming within the scope of the following claims. Having thus fully describedthe invention, what is claimed as new and for which it is desired to 10 1. A metal cleaning and brightening composition consisting essentially of 97.92% water, 25% phthalic anhydride, .61 sodium sulphate,- .6 1%

A soap, and '.61% soap bark,

2. A dry metal cleaning and brightening com-' position consisting essentially of 2 parts by weight of phthalic anhydride, 5 parts of sodium sulphate. 5 parts of soap, and 5 parts'of soap bark, adapted to be dissolved in' water for removing deposits 20' a and stains on metals, and preventing tarnishing HARRY B. Ramon.