USRE189E - Improvement in tanning leather by tannin and acids - Google Patents

Description

. the hides become I that bates and drenches and much labor are a suitable condition to receive the tannin, in

UNITED STATES PATENT OFFICE.

HARMON -HIBBARD, OF HENRIETTA, ASSIGN OR TO \V.

ESTER, NEW YORK.

IMPROVEMENT I'N TANNING L Specification forming part of Letters Patent No. 6,790, dated Octobe February 11, 1851.

To all whom it may concern.-

Be it known that I, WILLIAM W.

and State of New York, assignee of Letters Patent of the United States granted to HAR- MoN HIBBARD, of the town of Henrietta, in the county and State aforesaid, for certain Improvements in Tanning by Tannin and Acids,

- which Letters Patent, bearing date the 16th day of October, 1849, were assigned to me on the 23d day of October, of the same year, by deed, which deed was duly recorded on the 24th of November, year aforesaid, believing that said Letters Patent are inoperative and invalid by reason of a defective specification, have surrendered the same, and, according to the requirements of the acts of Congress in such case made and provided, have applied for a reissue of Letters Patent for the same improvements under the specification of the words following, viz:

The invention and discovery of HA-nMoN HIBBARD consists in new and useful improvements in the preparing of hides and skins for. tanning, and in the art or mode of tanning the same, with or without the hair or wool upon them, thereby making leather suitable for the various purposes to which hides and skins REID, of the city of Rochester, in the county of Monroe EATHER BY TANNIN AND ACIDS.

1' 1c, 1849; Reissue No. 189, dated texture are materially injured; but potash, being very soluble, is easily washed or worked out by water alone; besides it has a greater aflinity for fat or oil, and makes a soluble soap, which also is easily makes an insoluble soap, which is removed with more difliculty. Potash, being soluble, penetrates and softens the hide more speedily, and thus enables the lime itself to act sooner than it could alone; but fresh quicklime loos-' ens hair sooner than potash. Thus the two conjoined subserve a better purpose than either singly. Salt in solution also aids in softening dry or hard hides. It protects the substance of the hide from the too caustic action of the alkalies, loosens dirt, grease, 820., and thereby purifies the skin. It might be omitted in treating salted hides, unless soaked too long in water; but in all cases it preserves the substance and weight of thehides while undergoing the liming process. The nature of HIBBAR-Ds invention, so far as relates to the process of tanning, consists in the use of a composition of salt, sulphuric acid, and sumac, oak, hemlock bark, or any other tannin used for tanning: The salt, sulphuric acid, and tannin being mixed together in wathus tanned may be applied.

First, the nature of his invention, so far as itrelates to the preparation of hides and skins for tanning, consists in the use of a composition of lime, wood-ashes orpotash, and salt, for the purpose of removing hair or wool, and also for the process of liming, so called, instead of using lime alone, as in the old method. Lime and ashes or potash, and even salt in weak solution, have been used separately for the purpose of removing hair and wool, also for the process called liming that is, for removing grease, mucus, and other impurities from hides and skins, but not as above combined. It requires several days, and sometimes weeks, to efl'ect these several objects by the use of lime alone. Moreover, lime being nearly insoluble, impregnated therewith, so

required to remove it before the hides are in ter, in certain proportions hereinafter ineir tioned, a portion of the salt is decomposed by the sulphuric acid, forming sulphate of soda muriatic acid,) being absorbed by the water, 1 acts directly and rapidly on whatever of the alkalies may yet remain in the skins, dissolv ing and removing them, while it acts with equal rapidity on the hide itself, raising it or opening its pores, prepares it to receive the tannin, which, being present also in the mixture, immediately unites with the gelatine of the hide, forming leather more expeditiously than by the old method.

To enable othersskilled in the art of tanning to use thismethod, let them observe the following: For unhairing and liming, so called, and for pulling wool, prepare and use the following composition, which I denominate Composition N o. 1: good wood-ashes, one bushel, (or potash about five pounds;) freshconsequence of which their muscular fiber and slaked lime, four quarts; salt, about three quarts water, about one hundred gallons.

W. REID, or ROOH- worked out; but lime and set-ting muriatic acid free, which, (the taste.

These ingredients may be mixed together and the hides be put into the mixture for unhairing and liming; but for pulling wool, take lime and ashes, equal parts, and salt, one quart to one bushel of the mixture, and mix with water sufficient to makea thin paste, which ture for unhairing and liming; but for pull-- ing wool mix one bushel of lime and one quart of salt with good strong lye, making a thin paste, which apply to skins, as already described. Alittle practice will enable the operator to judge of the proper strength of composition No. 1. It should have a slippery ieel and quite a sharp alkaline It is readily made stronger by addition of more material, or weaker by adding water. The above quantities and proportions serve as a general guide. The lime and ashes or potash may be used in various proportions; but it is desirable that as little lime as possible to produce the desired effect should be used, because of its insolubility and'of its insinuating itself into the substance of the hide. The

7 hides or skins, having been properly soaked, softened, and broken, are to be put into composition No. 1 in a vat or vats, and handled in the usual way. The temperature may be kept at 50 to 60 Fahrenheit. As soon as the hair will come freely, they must be taken out p and put into clean, warm, soft water and soaked several hours, then thoroughly worked, fleshand grain, on the beam, then put back into the water, soaked again, and worked again till they are sufficiently reduced. They are then ready for the tanning process. As a general thing, hates and drenches will not be required, because the potash,being soluble, and the little limeused are easily washed out with water, and because composition No. 2, about to be described, used in the tanning accomplishes the identical objects to be obtained by bating and drenching. If any prefer, they may prepare their hides and skins after the old method. They can be tanned just as well by composition No. 2; but skins and hides prepared by the foregoing method will makev heavier and stronger leather than when prepared by the old process of liming and bating.

For tanning, make and use the following, which I denominate Composition No. 2 z Take sumac, oak-bark, quercitron, or any other tanning materials, either singly or combined.

- Bleach and make a strong infusion or ooze.

To every onehundred gallons of ooze, add salt, twenty pounds, sulphuric acid, two pints. These quantities serve as a general rule. A little experience will enable a'workman to determine by the color and taste as to the requisite proportions and quantities and strength of the composition without weighing or measuring. The salt should always be in. excess the flesh sides of the of the composition.

over theacid. If it is considerably more so, no harm can accrue; but if the acid should be in excess, injury might be done. There should be sulphuric acid enough to decompose enough of the salt to liberate an equivalent of muriatic acid, of which there should be so much as is sufiicient to give the hides a uniform color and cause them to swell or puff up slightly. The muriatic acid thus generated by the decomposition of the salt, by means of the sulphuric acid, attacks the alkalies that may remain inthe hides, dissolves or converts them into soluble muriates of lime or potash, and thus acts as a bate and drench on the hides to clean them, while at the same time it opens their pores, so that they imbibe the tannin more rapidly. It also precipitates or decomposes a portion of the coloring-matter of the ooze, and thereby renders the color' of the leather lighter, more lively and beautiful. If there is a deficiency of acid, so as not to neutralize all the alkalies remaining in the hides,

they will be spotted or dark colored. They will not raise or swell up. In such case more of the sulphuric acid must be added for the purpose of decomposing more of the salt, (which is supposed to be in excess,) and thusfurnish more of the muriatie acid.

Muriatic acid of commerce may be added to the tannin and salt, and they will produce nearly the same result. The sulphate of soda would be wanting; but this also may be added, and then we should have the same composition and precisely the same results, and when economy would warrant it, this course might be adopted; but at present cost of these mas terials it is cheaper to use sulphuric acid and salt, and thus generate both the muriatic acid and sulphate of soda. This method is also more simple. 7 i

, The hides and skins having been prepared in composition No. 1, as already described, they are then to be put into composition No. 2, prepared as above, in suitable vats and handled often. in the usual way. The strength of the eompositionmustbe kept up by additions of strong ooze, and also of salt and acid'when necessary, and in such quantities as will give the original taste, color, &c.

The time required to accomplish the process of tanning will depend on the quality and size of the hides or skins orkinds of leather to be made, and on the strength and temperature If the strength be good, the temperature about 80 Fahrenheit, and the handling properly conducted, most kinds of leather may-be tanned in less than half the time required by the old method of tanning now in use in our country. When the hides are sufficiently tanned, those designed to be curried may be curried and finished in the usual way. If the process has been properly conducted, they will require much less scouring, whereby some hard labor is saved.

When it is intended to black and finish on the grain, in order to remove any excess of salt and acid that may remain in them and interfere with the finishing, after removing them from the vats soak them one hour or less in a clear ooze made of the same kind of tannin used in tanning them, then rinse and strike them out of clean soft water, after which immerse them in the following composition: .To every gallon of soft water add of good soft soap one quart; best sperm or cod oil, one pint. Mix and beat these ingredients well together. Aflzer being dipped in this mixture let them sammy or 'dry'partially, then shave, set, and stuff them. For stuffing use common stuffing and soft soap, equal parts, or sad and cod oil,

'equabparts, after which, if to be finished on the flesh side, proceed in the usual way; but

if to be blacked on the grain, wet or sponge them when nearly dry on the grain side with a weak solution of potash or sal-soda, then apply a thin coat of blood and acetate of iron as used by morocco-dressers. Let them nearly dry, then repeat the coat of sal-soda and mixture of blood and'acetate of iron, then set them smooth on both sides, oil and dry' them.

Deer, sheep, and similar skins designed for buck or imitation of buck-such as are used for gloves, mittens, and military trimmingsshould be frized after being prepared in composition No. 1, and unhaired and then tanned in composition No. 2, prepared with sumac. When tanned, rinse and strike them out of clean soft water, then hang up to dry. When dry, finish on a perch with a stake, moon-knife, and pumice-stone; or, to make them soft and elastic, they may be milled first, before quite dry, and then finished with perch,

moon-knife, at, the same as in oil-dressing, but without any oil.

In order totan hides or skins with fur, hair, or wool on, they must first be washed thor oughly clean in a weak potash lye or in soft soap and water, (care being taken not to keep them in so long as to start or loosen the fur, &c.

then flesh and break them, rinse in clean soft water, then tan them in composition No. 2.

To make white leather sumac should be used in making composition N0. 2. I

What I claim, and desire to secure by Letters Patent, is v 1. The process of removing hair and wool .from hides and skins and of liming them,

so called, preparatory of tanning, by the use of a composition of lime', wood-ashes or potash,

and of salt, called Composition No.1, in the manner above described.

2. The use of a composition of lime and woodashes or potashwithout the salt; but I do not claim either of these materials separately by itself.

3. The process of tanning hides and skinsby the use of any kind of tannin, in combination either with the muriatic acid of commerce-or with muriatic acid generated by a mixture of sulphuric acid and salt in Water with the tannin, in the manner substantially as above de-