US2391653A - Goldbeater lubrication material - Google Patents

Description

entedJuly 18,1944.v

' My present invention relates to the goldbeaters Patents Dec. 25, 1945 STATES ra'rlazu'l" oFFlcs 2,391,653 connnusraa LUBRICATION MATERIAL Donald 1). Swift, Hartford, Conn., assignor to M. Swii't & Sons, lnc., a corporation, of Connecticut No Drawing. Original application October 28, 1939, Serial No. 301,797, now Patent No.

r 2,354,072, dated July 18, 1944. Divided and this application July 18, 1944, Serial No. 545,539

2 canine (cl. ess-42.1)

- This application is a division ofapplication Serial No. 301,797, flied October 28, 1939, Goldbeating lubricant, now Patent No. 2,354,072, pat;-

" ess is continued until the leaf has reached the desired size and thinness.

The conventional goldbeaters skins are of ani-- mal origin, but substitutes such as Cellophane or cellulose acetate may be used. To facilitate the beating operation, it is customary to doctor the oldbeater's skin or the substitute and toadd a suitable lubricant. The conventional doctorin long used for this purpose consists essentially of isinglass, gum arabic, shellac, and spices such as safiron, cinnamon, and cloves in red wine; The lubricant is usually made up from soap, gypsum, and water. or in some instances, alcohol.

I have found that a greatly improved goldbeaters lubricant is obtained by the useof a mineral carrier which is soft enough to be scratched by a fingernail and which can be subdivided to almost microscopic dimensions. I have found ,that the lmbedding of such a mineral carrier in a fatty acid sodium salt produces a far superior lubricant. Y I

To this end, I prepare the lubricant of the present invention by dissolving a fatty acid sodium salt such as sodium stearate or sodium palmitate in a suitable alcohol such s prOPYil alcohol: suitable'orsanic soaps may be used in place of the sodium stearate or palmitate. The desired characteristics of the salt are that it be soluble in alpowder form,'-is then mixed into the solution; an alkaline earth soap, such as calcium, magnesium I or zinc stearate, may be used instead of the calclumsulphate. It is preferred that a uniform mixture be obtained so that the fine particles of the dehydrated calcium sulphate powder or soap are suspended in the solution of the sodium stearate or sodium palmitate in alcohol, the alcohol tending to inhibit hydrolysis of the soap. The alcohol is then evaporated by any suitable, wellknown method and the residue is a smooth, finegrained lubricant far superior to any that have heretofore been used.

It is preferred to use such proportions of the sodium stearate or sodium palmitate and the completely dehydrated calcium sulphate that the final product comprises particles of calcium sulphate each covered with a surface layer of soap. For example, 6 /2 oz. of sodium stearate are dissolved in about 3 qts. of alcohol. After the soap is completely dissolved, 12 lbs. of completely dehydrated calcium sulphate in a finely powdered form are slowly stirred into the solution. The

alcohol is then evaporated.

Theresultant lubricant is fine grained, soft,

will not scratch or puncture the gold or other metallic leaf during the beating operation and has very superior lubricating qualities.

While I have described a specific mineral carso rier and specific soaps, it is obvious that other cohol, non-adhesive, with a fairly high meltin 4 c rrie s and other soaps or their equivalents may be used in varying proportions, without departing from the spirit and the scope of the invention as defined in the appended claims.

Iclaim:

l. The method of preparing a lubricant for metal beating, comprising the steps of dissolving sodium palmitate in alcohol, mixing completely dehydrated calcium sulphate uniformly therein to obtain a suspension of the calcium sulphate in the solution of sodium palmitate. and evapcrating the alcohol.

2. An improved lubricant for'metal beating comprising comminuted particles of dehydrated calcium sulphate, each particle being covered by a urface layer of sodium palmitate.

DONALD D. SWIFT.