US401715A - Erik ollestad - Google Patents

Description

UNTTED STATES ATENT OFFICE;

ERIK OLL lSTA'D, OF ST. PAUL, MINNESOTA, ASSIGNOR OF ONE-HALF TO ANDREIV .IENSON, OF SAME PLACE.

TANNING PROCESS.

SPECIFICATION forming part of Letters Patent No. 401,? 15, dated April 16, 1889.

Application filed March 2, 1888. Serial No. 265,955. (No specimens.)

T0 aZZ whom it may concern:

Be it known that 1, ERIK OLLESTAD, a citizen of Norway, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and u seful Impro vementsin the Process of Tanning Hides; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilledin the art to Which it appertains to make and use the same.

This invention relates to an improved process of tanning; and it has for its object the production of a softer and finer leather and stronger in much shorter time than hereto fore, as will be more fully hereinafter described, and then specifically defined by the claim.

The ordinary method of tanning by the use of bark has one objection-that of consuming too long a time in the process of tanning. Certain chemicals have been used of late which have considerably shortened the time of tanning; but those that have been used heretofore have not been entirely successful in producing as good results as from the old method of bark-tanning. In my method I not only accomplish as good results as from the bark process, but make leather a great deal stronger and more water-proof, as well as softer and more pliable. I make use of both chemicals and extracts. By extracts Iwish to be understood as covering any extracts that may be used for the purpose of tanning-such as the extract of hemlock-bark, the extract of oak-bark, japonica, &c. I use the extracts also for the reason that by using both chemicals and extracts the leather by being tanned in this way obtains the same properties as leather tanned in the ordinary bark process, which fact is of great importance to the subsequent preparation in dyeing cf the leather. The chemicals I make use of are blue vitriol, bichromate of potash, al um. and sulphuric acid. Soaking, fleshing, and the removing of hair are done in the usual way. Large hides for belting or for other purposes where unusual strength is required are taken after the hair and flesh have been removed and placed as they are in the liquor.

The proportions of the ingredients used are as follows: In tanning ten ordinary hides I been thoroughly dissolved I take one-fourth part of the same and put in a vat, together with the necessary water, which is then poured into the stufiing-wheel. This liquor is then heated to a temperature of from to Fahrenheit, after which the hides are placed in the liquor, and the stuffing-wheel is kept turning around about one hour at a time three times per day. The third day the hides are taken out and another one-fourth part of the above-named solution is added to the liquor in the stuffing-wheel, which is then heated to a temperature of 30. The hides are again placed in the stufling-wheel, which is kept turning around at intervals, as before, until it is apparent that the liquor has lost its strength, when thehides are again taken out, and the remaining one-half of the solution is added to the liquor in the stuffingwheel, which is also heated to a temperature of 30, and after the hides have been replaced therein it is kept turning around at intervals, as before, until in the course of about fourteen days the hides will be tanned. In the washing of the leather I make use of ordinary lye extracted from maple-wood ashes and rub it well with good boiled trainoil on the grain or hair side, and with threefourths part train-oil and one-fourth part of rosin, which is boiled together, on the flesh side. The leather is now rubbed well with the above-named mixtures, according to its thickness, and hung up until about one-half dried, when it is taken down and stretched and hung up again until entirely dried. It is then taken down, rolled, and finished.

In tanning skins or upper-leather, kid, &c., allimpurities must first be removed, which is done in the ordinary way. I now make use of muriatic acid (the quantity being small, just sufficient to continue to make the tannic liquid sour) instead of sulphuric acid.

The time absorbed in tanning, on account of the skins being lighter, is also reduced from two to eight days. After the skins are tanned and taken out of the liquor they'are thoroughly rinsed and washed in lye. They are then rubbed with a boiled mixture of trainoil and tallow and hung up until about oneha'lf dry, when they are taken down and the above-11 amed mixture thoroughly worked into the skins and again hung up until entirely dry. The skins are now placed in lye that is heated to a temperature of 25, and all the grease is then washed out until they are entirely clean. They are then stretched and smoothed and again hung up to dry, after which they are ready for dyeing.

Importance is attached to the use of the blue vitriol and bichromate of potash, as