US1829302A - Method of making patent, japan, and enamel leathers - Google Patents

Description

Patented @ct. 27, 1931 SAMUEL S. SADTLER, OF SPRINGFIELD TOWNSHIP, MONTGOMERY COUNTY, AND

' EUGENE F. CAYO, F PHILADELPHIA, PENNSYLVANIA METHOD OF MAKING PATENT, JAPAN, AND ENAMEL LEATHERS No Drawing.

This invention has particularly to do with the preparation of leather, particularly that made from horsehide and goat skins, for the manufacture of patent, japan or enamel leather. In the ordinary processes of making such enamel or patent leather, it is customary to subject the leather skins to a treatment whereby the oils remaining in the skins, as a result of the previous fat liquoring of the skins in the process of making leather, are

usually applied, quite absorbent. Moreover,

the abstractions of these oils involves an additional step in the process, lengthens the time required to make patent or enamel leather, and correspondingly increases the cost of making it.

It is one of the objects of the present invention to eliminate this step of extracting the oils contained in the leather skins or hides and to retain within the skins the oil present therein as the result of previous steps in the leather-making processes. A further object of our invention is to protect the enamel from anything that would penetrate through the leather to the flesh side.

A further object of our invention is to reduce the number of steps of treatment required for producing patent or enamel leather, by making it unnecessary to extract the oils contained in the leather hides or skins by the naphtha or any other process and to render the flesh side of the leather practically incapable of absorbing the enameling materials.

is softer, thinner, more durable and more flexible than that produced by the processes heretofore practised.

Application filed March 19, 1927. Serial No. 176,834.

Other objects of our invention will appear in the specification and claims below.

In carrying out our invention, we take the leather hides or skins as they come from the leather makers, and containing the oils or oily materials usually contained therein and provide that side of the hide which is to be enameled with a film of a gum or gum-like material which is practically not soluble or miscible in the oils of the enamel coating materials to be applied thereto, which film is also flexible and impervious to water and to grease or oil that is already contained in the skin or hide, whether such oil be natural, or worked into the skin in the previous process of treating the same.

For the purpose of providing this film we have found that a shellac-like material such as (1) a solution of shellac in alcohol or (2) the esters of cellulose are both well ada ted for the purpose, but the former we have found to be preferable.

In the practice of our invention, we preferably prepare and use a solution of shellac, for instance, ordinary orange shellac in alcohol, and to this solution we add a finely divided filler which is insoluble in the alcohol or other solvent of the shellac or other film forming material employed.

The pores or interstices of the leather and particularly on the flesh side of the skin are very absorbent. This filler is for the purpose of filling the pores of such porous surface of the leather with an insoluble material which will operate to fill or clog up the pores, to prevent the absorption of the shellac solvent into the skin or hide, and to hold the shellac solution on the surface of the skin or hide until such time as the solvent has evaporated, leaving a film of shellac on the surface or surfaces of the leather so treated.

As an instance of a preferred solution for applying to the leather before enameling but one which may be varied and modified to a considerable extent without departing from the spirit and scope of our invention, we may use a 5% shellac solution in alcohol. To this we add a suitable filler, which should be without the characteristics of a pigment.

This filler may be finely divided, silica, clay,

' I stretched on boards.

aluminum oxid, aluminum hydroxid or barites. We prefer to use a colloidal clay, such as bentonite, which tends to remain. suspended in the solution, does not appreciably increase the opacity of the film, and fills or clogs up the pores in the desired manner. The use of such an inert filler is particularly desirable. in the treatment of soft leather, such as those made from goat skins for the production of a soft patent or enameled leather. To give a desired color to the leather a suitable alcohol-soluble dye may be added to the shellac solution. Such a dye may be aJnigrosine base, which is developed by the acidity of the shellac.

A suitable compositidn for the practice of our process maybe made of'the following ingredients, thoroughly mixed together, in the following proportions:

' The leather is prepared for patent leatherlng, enameling or japanning in the usual way,

' except that the step of extracting the oil from the leather skin prior to the ap lication of the enameling or patent leathermg thereto, as heretofore practised, is omitted. The leather skin to be treated is nailed and tightly In the ordinary process of enameling leather, the leather skin, with the oil extracted from the skin is stretched on boards and given a coat of leather enameling material which usually consists of linseed oil, litharge, Prussian blue, lampblack and similar ingredients, thinned to proper consistency with light petroleum, and by leather enameling material, we mean material of this character,'which, when applied to flexible material such as leather, is very flexible, tenacious and susceptible of high polish. The first layer or coat is general y applied thick because of the absorbent property or quality of the leather, particularly on the flesh side. The first coating or'daub contains a suitable amount of oil as an essential ingredient, and to prevent this absorbent surface of the leather from absorbing the oil out of the daub and to prevent the leather enameling leather, thecoating material is made just as thick and dry as it is possible to make it and permit of its being spread over the surface 'of the leather with a slicker. In carrying out our improved process, however, the leather skin or hide, with the natural oils and greasesin it, is stretched and nailed on the boards and given a thin coating of our shellac solution with the filler and possibly a color base contained therein as above described,

This coating material is appliedto the surface of the leather in any suitable and convenient manner but it should thoroughly coat and such that it may be sprayed on the surface or applied with a brush. After such application of the coating material to the leather,

"skin or hide, the coating is allowed to dry by the evaporation of the solvent, whereuponthe leather so coated with-our said composition above described, is ready for the leather enameling process.

When the flesh side of the skin is the side to which the leather enameling is to be ap-v plied, it is to that side that our film of shellac or similar gum-like material is applied. When the leather enameling is to be applied to the grain side of the hide of the skin, then our protective film or coating is applied to the grain side of the leather. This film is operative to prevent the first layer of paste or thick enameling material or the oily content thereof from penetrating into the pores of the leather. It firmly adheres to the film but does not substantially penetrate into the hide.

The film having been so applied, the leather is then subjected to the leather enameling process, comprising the application of the first or ground coat, of leather enameling material similar to that used in former leather enameling processes but this ground coat may be and preferably is somewhat thinner than the daub heretofore employed in enameling processes. The film of shellac covers the surface of the leather to which the first coat is applied and is not soluble or miscible in the oils (which may be boiled linseed oil) contained in the first or ground coat. After this first coating has been applied, the leather so coated is placed in a hot stove or oven and allowed to remain there until the ground coat is thoroughly dried andbaked, whereupon it is then removed from the drier and pumiced smooth. Thereafter, a thinner coat of similar leather enameling material may be applied andthis coating may be similarly heated until thoroughly dry. This coating is then subjected to a similar process of pumicing it smooth, whereupon a thin finish coating of japan or copal varnish is applied.

Because of the fact that the film which we have provided'for the skin or leatherfprevents the leather enameling material from penetrating into the normally porous dry surface of the leather, the first orpriming or ground coat of enameling material may be applied in a thinner or more fluid condition to produce I enamel is thinner, and the original leather is soft and flexible due to the oil and grease content thereof, the patent or enameled leather made by our improved processes is more flexible and less liable to crack when the leather is flexed or bent than the patent leathers made pursuant to prior processes.

The leather of the patent or enameled leather so produced contains and retains much more oil than that present in ordinary patent leather or enameled leather and consequently the finished product will be more flexible, softer and less liable to crack.

Having thus described our invention, what we claim and desire to protect by Letters Patent of the United States is: Y

1. The process of enameling leathers from which the oils and greases remaining therein from the leather making processes have not been removed, which consists in applying to the surface of said leather containing said oils and greases a coat of shellac dissolved in alcohol and mixed with colloidal clay, to fill the pores of the surface of said leather with particles of clay and to thereby prevent the leather from absorbing the solution and to retain the shellac content of the solution on the surface" of said leather until the solvent shall have evaporated, then enameling said surface by applying successive coatings of patent leather enameling materials and thoroughly heating and drying the same after each application thereto of each coating.

2. The method of making leathers from which the oils and greases have not been extracted, which consists in applying to a surface of said leather a coating composed of a solution of a flexible shellac-like substance insoluble and immiscible in the oils and greases contained in said leather and insoluble and immiscible in the usual leather enameling compositions, said solution containing an inert finely divided filler suspended'therein and operative to fill the pores of said leather and to thereby prevent the leather from absorbing said solution and also containing a dye soluble in the solvent of said, solution, permitting said coating so applied to dry by the evaporation of said solvent, and then applying thereto successive coatings of patent leather enameling materials and thoroughly heating and drying the same after the application of each coating.

3. The method of enameling leathers from which the oils and greases normally present in leathers have not been extracted, which consists in applying to the surface of said leather, a coating comprising a solution of a flexible shellac-like substance insoluble and immiscible in oils and greases, and containing an inert filler having substantially n pigmental properties and operative to fill th pores of said leather, thereby greatly checking the absorption of said solution into said leather, permitting the coating so applied to' in said solution finely divided inert insoluble material operative when applied to clog and fill the pores of said leather at the surface thereof to prevent the solvent of said solution and the gum-like material dissolved therein from substantially penetrating the fibrous material and to hold said gum-like material on the surface of said leather until said solvent evaporates, thereby permitting a film of said gum-like material over the surface of said leather and then applying over said film successive coatings of suitable patent leather enameling materials and heating each coat to thoroughly dry the same after the application thereof to said leather.

In witness whereof, we have hereunto set our hands this 17th day of March, 1927.

SAMUEL S. SADTLER. EUGENE F. QAYO.