US798294A - Process of treating hides. - Google Patents

Description

FRANCIS J. OAKES, OF NEW YORK, N. Y.

PROCESS OF TREATING HIDES.

Specification of Letters Patent.

Patented Aug. 29, 1905.

Application filed March 31,1905. Serial No. 253,144.

' To all whom, it may concern:

Be it known that I, FRANCIS J. OAKEs, a citizen of the United States, and a resident of the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Processes of Treating Hides, of which the following is a specification.

The object of my present invention is to improve present processes relied upon for the extraction from hides or skins of the caustic lime or other calcium compounds left therein by the well-known liming processes for dehairing or depilating. These processes are commonly known as bating or puering.

That particular aspect of my invention presented in the present specification relates more particularly to those bating or puering processes which depend upon putrefactive action and which consist, generally speaking, in soaking the hides in a bath containing putrefactive agents, such as dog dung or other excrementitious matter.

In the hating and puering processes referred to the baths employed as aforesaid have been found to be unduly alkaline, whereby the hides are undesirably plumped,their gelatinous constituents injuriously affected, and their fiber consequently weakened, and it has heretofore been unsuccessfully sought to sufficientl y neutralize such alkalinity during the application of the processes referred to, but without checking or impairing the requisite putrefaction and consequent bacterial action upon the hides depended upon for the lime extraction and also in certain cases for imparting a desiredfinish and appearance to the final leather product as, for instance, in the case of so-called glazed leather.

I have discovered that the desideratum referred to may be obtained by the use of sulfur in the manner hereinafter described.

It seems that the putrefactionof the excrementitious substance referred to generates an undesirably large amount of ammonia, also hydrogen sulfid, which unites therewith to form ammonium sulfid, thus creating afterward in the bath a strong and injurious alkaline condition, but that this ammonium sulfid, together with any excess of ammonia present, coacts with the sulfur, as added by me, to form polysulfids havingamuch milder alkaline reaction, and consequently a less injurious and even a benign effect upon the hides as compared with that of the other chemical compounds which would otherwise be presentas, for instance, ammonium hydrate or ammonium carbonate.

Without here-enumerating in detail each,

and every of the many ways in which my said improvement may be beneficially applied I will give the following example in order that those skilled in the art may understand what I now regard as the best way of practicing my invention, viz: I first'prepare a mixture of an excrementitious substance with sulfur in order to insure the presence of the sulfur from the beginning of putrefaction. I use, forinstance, the following proportions, viz: To about one hundred pounds of the dry excrementitious substanceIadd, say, five pounds of flowers of sulfur and mix the two together. I next add to this mixture suflicient water to form a semiliquid paste. By this means I insure the "presence of the sulfur from the very beginning of the resulting putrefaction of the excrementitious substance, so that the resulting products and compounds of the putrefaction are presented to the sulfur from the commencement and thereafter throughout the operation of my process in their nascent state. The mixture is then allowed to stand until the required extent and character of putrefaction has been developed. I then prepare an aqueous bath of the usual volume relatively to the hidessay in the ratio of about three pounds of water to'one pound of the hides treated. Into this bath I introduce a proportion of the said mixture of putrefying excrementitious matter, sulfur, and resulting compounds, say in the ratio of ten per centum of such mixture estimated on the weight of the hides to be treated. I then introduce the hides into said bath so constituted, the temperature of which is maintained, preferably,at about 100 Fahrenheit, until the required effect has been produced upon the hides, which may then be withdrawn for subsequent application thereto of any desired process.

The proportion of sulfur to be employed may vary somewhat according to circumstances; but it is preferable in all cases that the amount shall be such as to insure at all times during the continuance of my process the presence of an excess of that agent.

While the method preferred by me of utilizing the sulfur is that above described and which insures the presence of that agent throughout the entire process during the nascent stage of all the products and compounds resulting from the putrefaction, it will nevertheless be understood that the advantages of my invention may be realized, though less .comprehensively, by introducing the sulfur I claim as new, and desire to secure by Letters Patent, is the following, viz:

1. The process of treating hides which consists in soaking them in a bath containing sulfur and a putrefying excrementitious substance.

2. The process of treating hides which consists in subjecting them in an aqueous bath to the action of a mixture of sulfur and a-putrefying exorementitious substance, substantially as and for the purposes described.

FRANCIS J. OAKES.

Witnesses:

WALTER D. EDMoNDs, ALLEN ROGERS.