US848357A - Leather and process of making the same. - Google Patents

Description

.to manufacture. "coating the leather with a plurality of coat- UNTTE TATES PATENT FFTOE.

JEON FEVAL, OF NEWARK, NEW JERSEY, ASSIONOR, BY MESNE ASSIGN- MENTS, TO GUARDIAN TRUST COMPANY OF NEW YORK, TRUSTEE, A

CORPORATION OF NEW YORK.

LEATHER AND enoosss 0F MAKENG THE SAME.

Specification of Letters Patent.

Patented March 26, 1907.

Application filed May 2,1906. Serial No- 314,773.

ark, in the county of Essex and State of New Jersey, have invented a certain new and useful Improved Leather and Process of Making the Same, of which the following is a description.

The objects I have in view are the production of a finished leather which will possess great durability, freedom from cracking and other objections and a which will be cheap I attain these objects by ings, the inner coating or coatings being elastic, one at least of them containing a relatively large proportion of non-drying oil or oil not readily oxidizable and soluble nitrocellulose, which is preferably in solution with amylacct-ate and diluted with alcohol. The innermost coating is preferably formed by makin a portion of the diluent of alcohol, which by its quick evaporation will cause the pyroxylin to set before the amylacetate has an opportunity to penetrate the leather and deposit the pyroxylin on the surface of the leather in the form of a thin film. T he inner coating or coatings will never entirely dry, owing to the large proportion of non-oxidizing oil employed, and will remain always in a tacky or sticky condition. The outer coating or coatings preferably contain a much larger proportion of pyroxylin and a smaller proportion of oil. The outer coating or coatings will preferably be largely of pyroxylin and will set with a dry surface, which will cover and protect the inner coating or coatings. This outer coating will pref erably be very much thinner than the inner coating or coatings.

As a basis of the leather 1 use real leather as distinguished from artificial leather. Small skins or large hides may be used, and the invention may be applied with success to the less expensive splits, as well as to the more expensive grained and buffed leathers.

For the oil I employ a non-drying oil--that is, an oil which is not readily oxidizablc. As examples of such oils Lmay mention caster-oil and peanutoil, both of which are abundant and serve the purpose admirably. Other oils which answer the requirements,

invention. For the nitrocellulose I prefer to use a nitrated cellulose readily soluble in amylacetate and inethylic alcohol, such as pyroxylin or guncotton. This nitrocellu lose may be in solution in a solvent proper, such as amylacetate, or in a solvent mixed with a diluent, as fusel-oil. oil and the nitrocellulose I may use gums or other substances togive body to the coating and pigments or other substances to, give color; but they are not necessary.

One way of carrying out the process is as follows: The uncoated leather is first coated with a liquid containing the oil and nitrocellulose 1n solution and preferably diluted with alcohol with or without other materials, such as gun' sor pigments. This inner coating is allowed to set, (preferably at ordinary temperature.) The first or inner coating when sufliciently set will not be entirely hard and inflexible, owing to the presence of the large proportion of non-drying oil, but, on the contrary, will be tacky and more or less soft, flexible, and elastic. A second coating is then superposed upon it. This outer coating may be like the inner one except that it has a smaller proportionof the oil than in the inner coating. In this outer coating :1 larger proportion of pigment may ter being always soft, and therefore impractical for a finished leather. If" desired, athird or other coatings may be added, these coatings being similar to the second coating. The process maybe modified by makingthe second coating or additional coatings, if such Together with the be used, similar to the first, with the outside or finish coating similar to the second coating above described.

As an example for carrying out my improved process the following proportions may be em loyed: For a steer-hide split or cowhide spit of average thickness for the first coating a solution of about thirteen pounds of pyroxylin dissolved in about thirhowever, may he used without changing the teen gallons of a mixture of three parts of ,voodalcohol and one part of amylacetate, which is at the rate of one pound of pyroxylin to each gallon of solution. To this is added about seventy-five pounds of castoroil together with about two pounds of any commercial pigment, depending upon the color desired, ground in about twenty pounds of oil. There is therefore used about ninety five pounds of oil, so that the oil will therefore be at the rate of about seven and one-third pounds of oil to each pound of nitrocellulose. As an example of coloring pigment for some shades of brown burnt umber may be employed. The inner coating will set and will not permeate the leather to any appreciable extent. One reason why this IS possibleis theuse of the wood-alcohol in large quantity, so that the composition will not entirely or much of it permeate the leather and change the character of the coating from one of reat elasticity and ability to stretch to a hlm'forincd largely of pyroxylin and incapable of being stretched. Instead of the woodalcohol some other material may be used to prevent permeation of the leather by theselution. For the jsccond coating the same amount of pyrorylin and amylacetate may be used, but with a smaller proportion of alcohol, depending upon the weather during the operation on account of its tendency to absorb moisture and then precipitate pyroxylin. To this is added sixteen pounds of castor-oil, being much less than for the first coating.

The amount of alcohol used in the second coating depends upon the weather during the operation. The second coating is m a position to absorb moisture, while the first coating is covered. Therefore if moisture be absorbed a spotted appearance in the coating results. it is possible to make it without alcohol; but the solution will penetrate too far unless other means be provided to prevent this, for the reason that the amylacetate dries too slowly. The amount of oil in the inner coating-is regulated by the thickness, texture, stillness, and in some cases by the method of tannage of the leather, and also by the lengthof fiber on the surface, if the leather is a split. A thick and close-textured leather will require a larger proportion of oil than. a thinner leather or one in which the texture is more open. In some instances chrome-tanned leather will require a smaller proportion of oil than a bark-tanned leather. The, hand-bullod and machinc-bidled leathers in require a smaller proportion of oil than the split referred to above, assuming the proportions to be the same in both cases.

The proportion of oil to nitrocellulose should be varied when used in connetion with other leatherssuch as goatskin, calfskin, according to the above rule. The proportion may vary from seven and one-half pounds of oil to each pound of nitrocellulose or even slightly more in some leathers down to very much less in other leathers. I find, however, that it may not well be reduced below three and one-fourth pounds to each pound of nitrocellulose This proportion of oil, it is to be understood, is to be measured by the amount of nitrocellulose employed and does not in any way depend upon the amount of solution containing the nitrocellulose. The proportion of oil in the outer coating will vary according to the results desired. A

smaller proportion of oil. will give a leather having a drier feel. Similarly a larger proportion of oil will give an increased sleekncss of feel. The amount of pigment added should be su llicient to secure the desired depth of color. The proportions used will vary with the results desired. The addition of gums or other oils may cause a slight reduc- Lion of nondrying oil. For instance, in connection. with the example before given if a gum or similar substance, such as cam hor, is used, and which is soluble in the sofvent used to dissolve the pyroxylin without acting on the pyroxylin, it would be in the proportion of about three-quarters of a pound to each. pound of Castor-oil used. After the leather is coated it may be further finished by graining, embossing, or pebbling in the usual way.

The leather produced. by this process possesses remarkable durability and freedom from cracking or splitting It is .parti.cu larly applicable for furniture, upholstery, or for use upon carriages and automobiles and for use in constructing thefoldinghoods or tops of carriages. in these situations the leather is subjected to severe treatment, strains, and exposure to the weather and is folded and subjected to treatment which would ordinarily cause cracking or flaking of the coatingv Leather made according to my process does not have the objections ordinarily incident to leathers made by old and well-known processes. I find that it may be very much more cheaply manufactured and made with greater expedition than ordinary coated leathers. The successive coatings do not have to be baked and may be quickly dricd without artificial hcat. l iu'thcrmore, a greater cheapncss is secured by using cheaper grades of leather to form the basisof the coated leather. l find that leather which is made from the split, dccp split, or deep buff according to my process is every way as good as,,if not better than, leathers madefrom the hands buff or machine-bull according to the old and well-known processes. Furthermore, it has the greater advantage of not drying out or getting still by age and will not be affected by cold weather.

Leather produced by this process as dis closed can be distinguished from all others follows: by chemical analysiswashing carefully, or rather dissolving carefully, the

surface coating of the leather preferably by running over the surface with a sponge inipregnated with amylacetate, then drying the leather and the remaining coating, then extracting, by means of benzene or ethyl alcohol, the oil-contained therein, then drying thoroughly the leather and Whatever coating has remained attached to it after-the extraction of the oil. The difference in weight between the original sample of leather submitted to analysis and its weight after the oil has been extracted will give the weight of oil it contains. The weight of nitrocellulose can easily be obtained by dis-= solving the same from the leather after the oil has been extracted, this dissolution being preferably made by means of amylacetate, which x'lze evaporated will'leave as residue the introcellulose. If color pigments are present, they may be separated or Weighed by burning the dry residue containing nitrocellulose and pigment. The final residue after the nitrocellulose has been burned out will represent the weight of pigment. This method of analysis will establish the proportion of oil to nitrocellulose, which by simple calculation can be expressed in percentage of oil to the total mixture of nitrocellulose and oil. The oil and nitrocellulose can be identified by any of the reliable tests given in text-books by chemical analyses.

By microscopical examination of a section of leather coated by this rocess the different coats may be identifie if they have been given at an interval of two or three days between each, the coats containing the large proportion of oil showing in section a heavier or thicker coat of a peculiar gelatinous appearance.

My leather when heated will give off a slight smell of non-drying oil used in the coating.

On cowhide, steer-hide, or bull-hide, such as is used generally for furniture, carriage, and automobile work, any hide not possess ing an inner coat containing at least three and onc-fourth pounds of oil to each pound of nitrocellulose will break on sharp bending or will remain too still and not sufiiciently pliable to be used for the above-stated pur poses, and the break or cracking of the eonios1t1on on the leather Wlll be recognized by its being of a nature of the breaking of a brittle \n'iaterial. The. interposition of a piece of ordinary wrapping-paper between a plate heated to 160 Fahrenheit or less and the leather made according to my process will leave on the paper oil stains at the points where the paper touches the leather.

' Split leatherthat is, the part of a hide near to the flesh finished or coated by my process will be recognized .by its resistance to breaking and its appearance absolutely similar to inachinc'bull and even hand-bull or grained leather made by other processes.

My leather will also be readily recognized, because with the ut'rnost skill. and care it is impossible to produce a coated cowhide, steer-hide, or bull hide of the nature of leather used for furniture, carriage, and automobile triniming with nitrocellulose and a non-dryi' oil in the proportionof less than three and one-fourth pounds of oil to each pound of nitrocellulose in which the coatings would not crack on sharp bending and yet have the coating so thin that'it could be hardly appar- I have beenabl'e to;

ent to the naked eye. produce on these same leathers a coating containing from three and one-eighth to three and three-sixteenths pounds of oil to each pound of nitrocellulose adni'ch wouldnot crack readily on sharp bending; but the thickness of the coating had to be such that on the section of the coated leather itwas plainly apparent to the naked eye and for this reason made the resulting coated leather too stifi to be readily marketable and much .too expensive to be .of commercial ,value'.

In fact, such leather with such a thick coatin is much more unsatisfactory; than the metho of producing leatherby the ordinary known linseed-oil process, besides in most cases the leather thus coated will getbrittle after it is one or two months old. This leather also on account of its heavy feel can absolutely couches, carriage-cushion, and automobiletrimming.

Having now particularly described and as certained the nature of my invention and in what manner the same is to be performed, I

' not be used for tufting purposes to which it is intended as, for instance, the tufting of' too declare that what I claim, and desire to se- I cure by Letters Patent, isv

1.-The process of coating leather which consists in coating the leather with a plural ity of coatings of a liquid containing a soluble" nitrocellulose and a non-drying oil, one at least of the inner coatings containing oil at the rate of at least three and one-fourth pounds of oil to each pound of nitrocellulose.

2. The process of coating leather which consists in coating the leather with a coating of a liquid containing a soluble nitrocellulose and a non-drying oil, the said coating containing oil at the rate of at least three and one-fourth pounds pf oil to each pound oI" nitrocellulose, then coating the leather with" anda non-drying oil, the said coating eonliounds'of oil to each pound of nitrocelluposed coating or coatings of a liquid contains ing a soluble nitrocellulose.

.pounds of oil to each pound of nitrocellulose,

taining oil at the rate of as much as six ose, then coating the leather with a super- 6. The process of coating leather which consists in coating the leather with a coating of aliquid containing a soluble nitrocellulose and a non-drying oil, the said coating containing oil at the rate of as much as six then coating the leather with a superposed coating or coatings of a liquid containing a soluble nitrocellulose and a smaller proportion of oil.

7. As a new article of manufacture, leather eases? coated with a plurality of superposed coat-- ings' formed of a liquid containing a soluble nitrocellulose and a non-drying oil, the said leather being flexible, one at least of the inner coatings containing oil at the rate of at least three and one-iourth pounds. of oil to each pound of nitrocellulose, the leather when heated giving off a slight odor of the nondrying oil, and not cracking when sharply bent.

8. As anew article of manufacture, leather coated with a plurality of superposed coatings formed of a liquid containing a soluhle nitrocellulose and a non-drying oil, the said leather being flexible, one least of the inner coatings containing oil atthe rate of as much as six pounds of oil to each pounc of i'iitrocollulose, the leather when heated giving oil a slight odor of the non-drying oil, and not cracking when sharply lient.

This specification signed and witnessed this 24th day of April, 1906.

LEON FEVAL.

Witnesses:

l nmonsoo nn SROIA, Av MoUTuNY.