US1703675A - Method of decorating leather and improved decorated leather - Google Patents

Description

Patented Feb. 26, 1929.

UNITE-D STATES I 1,703,675 PATENT-1 OFFICE.

\VINTHROP STANLEY LAWRENCE, OF BROOKLYN, NEW YORK, ASSIGNOR TO KAUMA- GRAPH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD 'OF DECORATING LEATHER AND IMPROVED DECORATED LEATHER.

No Drawing.

My invention relates to a new and improved method of decorating leather, and to a new and improved decorated leather.

One of the objects of my invention is to 5 provide a method whereby leather can be decorated in one or more colors by a direct lithographic process so as to produce a maximum number of color combinations at a minimum expense.

Another object of my invention is to provide a method of decorating leather by a printing process which will permit the use of a variety of color combinations and which Willprevent the ink from smearing upon the surface of the leather.

Another object of my invention is to provide a new and improved form of decorated leather made according to my improved method, it being understood, however that the claims herein for the new and improved decorated leather are not limited to anypar ticular process for making the same.

Other objects of my invention will be set forth in the following description which illustrates a preferred embodiment thereof, it

being understood that the above general statement of the objects of my invention is intended to merely generally explain the same, and not to limit it in any manner.

Various methods for decorating leather have been known for a great many years, but these methods have all been relatively expensive and they did not permit the ready and cheap application of designs in a great many color combinations.

It has been proposed, for example, to apply a decorated design to leather by means of a dyeing process, but this method has been very expensive.

It has also been proposed to coat leather so as to provide a surface layer which will readily take up ink, but this method has proved impractical for decorating leather for various purposes, as for example, in makingturn shoes because the surface film did not stretch as readily as the moist leather, so that the surface film tended to crack and peel off when the leather was stretched.

According to my invention a great variety of designs in a great many colors can be simply and efliciently produced by a direct lithographic or other printing process.

My invention is particularly applicable to decorating thin skins such as calf skins and kid skins which are afterwa ds used for mak- Application filed January 26, 1927. Serial in. ieasso.

ing turn shoes, in making which it is necessary to moisten the leather so that it can be readily stretched. According to my invention the individual skins are caused to adhere to bases made of thin bendable card board or paper by means of a binder or adhesive which is preferably insoluble in Water. F or this purpose a No. 3 and a No. 8 lithographic varnish, mixed with a suitable cobalt dryer can be utilized. The skins can be connected to these paper mounts or bases by means of the adhesive and then piled up and subjected to pressure until the adhesive has set at ordinary atmospheric temperature.

This lithographic varnish mixed with the dryer is a base for lithographic inks and it can be directly handled upon a lithographic press. Hence, the adhesive can be applied I to the paper base by means of an ordinary lithographic press which is a decided advantage because the use of a lithographic press makes itpossible to apply the adhesive t6 the paper base either continuously or in separated spots or 111165.

Each skin 1s, therefore, caused to adhere to its paper mount or base in a perfectly fiat condition. Since the edges of the skins often have a rounded contour because they have been taken from a portion of the body ofrthe animal having a rounded contour, it is preferable to make V-shaped cuts in the edges of the skins whenever this is necessary, so as to cause each skin to lie perfectly flat and tightly adhere to its mount.

It is preferable to use an adhesive which is insoluble in water because some of this adhesive often creeps to the outer surface of the skin. If the decorating process is applied to leather which has a water soluble surface film, then'this film flakes ofi when the leather is moistened in the process of turning a shoe or the like, and this injures the quality of the decoration.

Each combined mount and skin can ,now be fed to a lithographic press in the ordinary manner, ,or be printing device.

However, in order to render decoration on the leather by a direct printing process (lithographic or otherwise) practical it is necessary to first subject many kinds of leather to a degreasing process even before the skin is connected to its mount, and it is also necessary to usecertain. special inks. This degreasing printed by any other type of U process is not necessary with certain of leather, such as mocha, lambskin and other mark can be secured. On the other hand, un-

leathers commonly designated as suede.

I have discovered that unlesskid-and calf leathers are degreased by a suitable commercial process before they are printed upon, that the greasy substances present in atanned calf skin or-kid skin form a surface layer which penetrates the lithographic ink so as to prevent it from properly oxidizing and setting so that the decoration tends to smudge which, of course, would render the entire process impractical.

' Even ifsuch-skins are subjected to the ordinary degreasing process before they are lithographed, a certain amount-of grease always remains in the skin.-

I have discovered thattifordinary print- I ing or lithographic inks are employed in this process, that the grease present in such skins penetrates the marking or decoration, or aifectsthe oxidizing of the printing or lithographic ink in some'manner, so that the setting of the ink is very much retarded. This disadvantage is cumulative because it takes-a'certain amount of time for the greasy substances .in' the skinto penetrate or act- .upon the lithographic ink. Hence, if the printing or lithographic ink is caused to set very quickly it will be unaffected by the greasy residues in the skin, at least to'such an extent 'thata permanent and non-spreading less the ink is caused .to setquickly it is gradually affected by the greasy residues in the skin, so that the time of oxidizing or setting I is very much increased and the final'marking readily smudges.

Hence, the printing-tor lithographic ink should have a sufficient percentage of cobalt which are ground much more fin ly Ehan has been hitherto "customary in making lithographic inks. v l q It was "heretofore considered that carbon blackcould not be utilized asa pigment in printing upon leather, by a lithographic process or otherwise, because an ink embodying carbon black spreads or smudges quite readily when used for printing upon ordi- For example,

nary paper. It was, likewise heretofore con- 1 sideredthat the lithographic process in particular could not be successfully used in printing upon a substance such as leather unless the leather were first provided with a smooth and impervious surface coating such as a lacquer or the like, because the paper which has been heretofore used in lithographic printing has had the pores thereof filled as much as possible b means of suitable fillers, sizing, and the hike.

I have found, however, that a black lithographic ink in which carbon black has been incorporated can be utilized for printing directly upon leather, even though the leather has not been'provided with an impervious surface film. The very fine carbon black coating and also have a film of adsorbed air,

[ or other dryer added thereto so as to cause it to oxidizeor set within twenty-{four (24) hours. Thisfigure is merely approximate and is 'merely given by way of example bethat the ink should have a suflicient amount cause such inksare not absolutely uniform ,even thou h they-may be made according to the same f ormula. c

I can, therefore, merely generally state of dryer incorporated therein so. that it should set before .it is so softened or acted upon by the greasy residues in the skin as to' make it impossible -.to secure a. permanent marking.

Instead linseed oil base, it is preferable to use. inks having a China wood oil base as these dry more quickly and give results much superior of using inks having the ordinary than when an ink having a linseed oil base is utilized. However, I do not wish to ex elude from my invention the use of a'linseed oil ink.

However, in using China wood oil inks, care must be taken not to utilize those pi ments which have achemical action upon t e cling to or .unite very firmly, with the de-' particles which ordinarily each have an oily greased leather so as to provide a very clear" and permanent marking, so thatthe'action of the leather is wholly different from that of ordinary paper in this respect.

In order to cause other plgments to unite with or adhere to the leather so as to afford a secure and permanent marking, it is necessary to grind such other pigments to a much greater degree. of fineness than has hitherto been practiced, before incorporating the pigment in its oily vehicle. For example, other pigments should be ground until about 75% of the particles are smaller in size than four (4) ,1., namely, .OO min. I believe that these very fine particles of pigment are adsorbed to a certain extent by theleather so'as to afford a very clear and permanent marking while coarser articles are not sufficiently adsorbed by' the l cather so that they forma marking which can be easily blurred or smudged. Examination has shown that in printing with an ink containing carbon black, or containing pigments which has been ground to sufficient fineness, that the carbon black or other pigment penetrates the surface of the leather to form a durable marking. I include letter-- press and other printing methods in my invention. That is, the ink is absorbed to a certain extent by being applied directly to the porous surface of the leather and by makmg the pigment particles substantially fine the are carried along with the ink below the sur ace of the leather 'to a certain extent. If any of the particles of pigment remain upon or above the surface of the leather they are so fine that the decorative marking produced does not smear.

4 the like.

It is not necessary that the-leather should i be connected to a mount before printing thereon but this is preferable as the'leather is much more easily manipulated. However, when the leather is connected to amount the adhesive should be properly chosen so that it should not enter the pores of the leather and stiffen it. If, for example, the leather becomes impregnated with an adhesive consisting of a drying oil such as linseed oil, then this oil becomes gradually oxidized so that the sheet of leather is stiffened. Likewise, although satisfactory results can be-sethe pores of the leather to stiffen 'i't. 'usina suitable lithographic varnish having cured if the leather is connected to the mount by a water soluble adhesive, this adhesive must be of a character which will not enter a su cient amount of dryer therein, the varnish previously mentioned can be caused to set without entering the pores'of the leather so as to leave greasy spots thereon and stiffening the leather. If a water soluble adhesive.

such as starch is employed this mustbe used very sparingly so that it will notventer the pores of the leather to stiffen it.

- I have described a preferred embodiment of my invention, but it is clear. that numerous chan es and omissions could be made without eparting from its spirit.

I claim 1. A method of decorating an unfinished and commercially degreased leather which consists in connectin the leather to a mount by means of an adhesive non-soluble in water andthen applying an ink having an oily base and a pigment directly to the exposed surface of the leather and before it is separated from its mount.

2. A method of decorating an unfinished and commercially degreased leather which consists in connecting the leather to a mount by means of an adhesive, causing the adhesive to set'without permitting it to enter the pores of the leather to an extent suflicient to substantially stiffen the leather, and then applying an ink having an oily base and a- -p1gment directly to the exposed'surface of g the leather and before it is separated from its mount. a

-3. A method of decorating unfinishedleather which consists in connecting the leather to a mount by means of an adhesive embodying a drying oil, causing the adhesive to set without permltting it to enter the pores of the leather to an extent suflicient to substantially stiffen theleather and then printing on the exposed surface of the leather before it is separated from its mount.

In testimony whereof I aflix my signature.

' vvnirflnor snnm umpires.