US3809597A - Article for the finishing of leather - Google Patents

Abstract

VIDUAL LEATHER PIECES. ALTERNATIVELY, THE METHOD MAY BE PERFORMED CONTINOUSLY WITH THE SUCCESSIVE FEED OF LEATHERS TO BE COATED BETWEEN A TRANSFER WEB PROVIDING THE DESIRED RELEASED LAYER AND A SUPPORTING WEB COMPRISING THE REQUISITE BACKING OR SUPPORT.

AN IMPROVED METHOD OF FINISHING LEATHER BY TRANSFERRING AN ARCYCLIC, POLYURETHANE, OR OTHER FILM-FORMING FINISH COATING FROM A RELEASE LAYER BEARING THE FINISH COATING TO THE LEATHER SUPPORTED ON AN APPROPRIATE BACKING. THE BACKING OR SUPPORT, THE LEATHER SUBSTRATES TO BE COATED. AND THE RELEASE LAYER ARE PRESSED INTO A SANDWICH-LIKE ASSEMBLY WITH THE CONCURRENT APPLICATION OF SUFFICIENT HEAT AND PRESSURE TO TRANSFER SUBSTANTIALLY THE ENTIRE FINISH COATING TO THE SURFACES OF THE LEATHERS AND THE BACKING OR SUPPORT JUXTAPOSED THEREWITH. THE CARRIER SHEET WITH A PERMANENT RELEASE STRATUM MAY THEREAFTER BE RE-COATED AND RE-USED IN FURTHER LEATHER FINISHING OPERATIONS. THE METHOD MAY BE CARRIED OUT BACK-WISE EMPLOYING DISCRETE BLOCKINGS AND RELEASE LAYERS FOR THE TRANSFER OF FINISH COATINGS TO INDI-

Description

May 7, 1974 H. H. coNNETT ARTICLE FOR THE FINISHING OF LEATHER Filed March 24, 1972 Y /l l/l l AUnited States Patent O 3,809,597 ARTICLE FOR THE FINISHING OF LEATHER Hugh H. Connett, Wayne, Pa., assignor to Ucote Corporation, Newark, NJ. Continuation-in-part of abandoned application Ser. No. 163,611, July 19, 1971. This application Mar. 24, 1972, Ser. No. 237,696

Int. Cl. B32b 1/04, 7/12, 27/08 U.S. Cl. 161-39 ABSTRACT F THE DISCLOSURE An improved method of finishing leather by transferring an arcylic, polyurethane, or other film-forming finish coating from a release layer bearing the finish coating to the leather supported on an appropriate backing. The backing or support, the leather substrates to be coated, and the release layer are pressed into a sandwich-like assembly with the concurrent application of sufficient heat and pressure to transfer substantially the entire finish coating to the surfaces of the leathers and the backing or support juxtaposed therewith. The carrier sheet with a permanent release stratum may thereafter be re-coated and re-used in further leather finishing operations. The method may be carried out batch-wise employing discrete blocking and release layers for the transfer of finish coatings to individual leather pieces. Alternatively, the method maybe performed continuously with the successive feed of leathers to be coated between a transfer web providing the desired released layer and a supporting web comprising the requisite backing or support.

Cross reference to related application This application is a continuation-in-part of copending application Ser. No. 163,611 filed on July 19, 1971, and now abandoned.

Background of the invention Finishes are conventionally applied to leathers to impart protective coatings thereto, to level the color, and to minimize natural defects in the leather skins or hides. At the present time such finishes are generally applied by swabbing (brushing) and/or `spraying the finish coatings upon the leathers; in some limited cases, as in the application of polyurethane coatings for patent leathers or for other effects, the finish coatings may be applied by flow-coating operations. In all such instances, sufficient finish is applied to the leather substrate to provide a continuous film upon the leather epidermis.

Typically, between two and six passes are required on conventional leather finishing equipment to deposit the desired continuous film on the leather substrates. Moreover, the leather may be plated between passes to facilitate the film-forming process and smooth out the sand-like surface formed by spray application of the finish. Each pass of the leathers to be finished through conventional finishing equipment subjects the same to pre-wetting and subsequent forced heat drying. Such operations tend to subject the collagen fibers to successive swelling and contraction, and impair the ultimate hand of the leather product.

The skins or hides employed in the manufacture of leathers differ from one another, not only in regard to the number, type and location of natural blemishes (scratches, scars, coarse grain, etc.) but also with respect to the character and quality of the skins or hides themselves. Different sections of any given animal skin exhibit varying absorption of leather finishes, and hence take on differing shades. Moreover, leather made from a well nourished, healthy animal has different absorptive characteristics from that made from a animal which is not as Claims "ice f achieve employing conventional leather finishing operations.

It is among the objects of the present invention to provide an improved method for finishing leather which may be efficiently and economically carried out, which requires only a single pass, and which provides more uniformly finished leathers than achieved in accordance with conventional leather finishing operations, and to articles which may be utilized in the practice thereof. These and other objects and advantages of the invention will be apparent from the following detailed description of preferred embodiments thereof, taken in connection with the accompanying drawing.

The drawing In the drawing,

FIG. l is a diagrammatic cross-sectional view, with the dimensions of the various materials exaggerated for purposes of illustration, showing the successive stages of the leather finishing method of the present invention;

FIG. 2 is a schematic cross-section of an apparatus for carrying out the leather finishing method in a continuous manner; and

FIG. 3 is a diagrammatic cross-sectional view, with the dimensions of the various strata again exaggerated for purposes of illustration, showing a differing configuration ofthe backing and release layers which may be used when it is desired to perform the leather finishing method batchwise.

Summary of the invention It has been discovered in accordance herewith that improved finishing of leather is achieved by a technique involving introducing each leather substrate to =be finished between a backing layer having a finish-receptive surface contacting the substrate and a release layer having a releasable finish coating thereon; transferring the finish coating from the release layer to the surfaces of the leather substrate and the backing layer superimposed therewith, substantially all of the coating being thereby offset from the release layer to the backing layer; separating the release layer from the backing layer and the finish-coated leather substrate thereon; and thereafter removing the coated leather substrate from the backing layer.

Empolying this method, conventional leather finishes may be applied with far greater uniformity than when previously known leather finishing techniques are so utilized. Finish coatings may be applied to leathers by the present method employing only a single step, such coatings defining continuous films which are ironed during the single finishing operation and which require no further aftertreatment. Moreover, the continuous finish film or coating produced in accordance with the present method does not darken open scars or other blemishes in the leather surfaces, but tends to level the color of differing portions of the leathers, e.g., scratches, scars or the like, more uniformly than conventional leather finishing processes.

Furthermore, when acrylic or polyurethane resin iinishes are applied to leathers utilizing the method of this invention fully cured, cross-linked resin coatings imparting greater durability, washability and solvent resistance to the finished leather may be formed. 0n the other hand, such resin coatings cannot be cross-linked employing conventional leather nishing processes since the duration and temperature of the heat treatment required to achieve polymerization with such techniques would leather fibers.

The method of the invention may be carried out either batch-wise or in a continuous manner to provide direct finishing of usable leathers in any quantity. Employing such method, it is unnecessary to maintain large inventories of leathers having differing colors or other finishes. Rather, any desired finish may be directly and immediately applied to the leathers in response to specific orders for products 4so Ifinished. Thus, in accordance with the .present invention inventories of the relatively inexpensive backing and release materials bearing releasable leather finish coatings need only'be maintained.

Yet afurther, concomitant advantage inherent in the method of the present invention is that such maybe employed withoutthe application or loss of large lquantitiesy destroy the of volatile solvents such as are frequently 'used in the" siprayapplication'of leather finishes. Apart `from economies in the use of processing materials thus achieved, used of this method thus decreases the risk of atmospheric pollutionland avoids the' necessity for solvent recovery or similar operations.

When it is desired to carry out the improved leather finishing method hereof in a large-scale, continuous manner the leather finish coatings may be applied to each successive leather substrate to be finished employing release and backing layers in the form of continuous webs. In such embodiments each leather substrate is introduced onto a continuous backing or supporting web having the finish-receptve surface contacting the substrate, the web is then fed with the leather substrate thereon into contact with a continuous release or transfer web having the releasable finish coating thereon, and the Ifinish coating is then transferred from the transfer web to the surfaces of the leather substrate and the supporting web superimposed therewith, substantially all of the coating being thereby offset from the transfer web to the leather surfaces. The transfer web is thereafter separated from the supporting web and the lfinish-coated leather substrate, andthe latter thereafter removed from the supporting web.

When, on the other hand, it is desired to finish an individual leather piece or pieces with any predetermined finish coating the method may readily be carried out batch-wise. In such instances, it is preferred tovprovide the backing and release layers in the form of discrete 'sheet material articles having substantially the same dimensions and secured to one another along at least one abutting edge of each such article. The layers thus providel a preformed finishing assembly which, upon insertion of Vone or more leather substrates as a filling therebetween, may be pressed sandwich-like to transfer the finish coating from the release layer to the juxtaposed surfaces ofthe f Aj l 3128092597 i' Y ,proportion of the Yconventie ,nel leather finishing .ccittlnQsi-` tions) comprise blends of acrylic polymers, spirit-soluble dyes, pigments, waxes and other additives for achieving the desired appearance and characteristics of the finished leather. Materials so useful when applied by the method of the present invention include acrylic resins such as those marketed by IRohm and Haas as fPifnaP resins (e.g., HA-65, E-32, E-760, E-826, AC'34, B-15, B-85, -B-88, LT-76, vLT-87 and :ASE-60); yspirit soluble. dyes such as 'Rohm and HaasfLS serie's,'K. J.. Quinnl & Co.s RD series, Chemical Coating Corporations "Hyconf series, and Du Ponts Luxal series;v "and pigments such'as Rohm and Haas Primal Colors and Sandoz v Relcasyn azo pigments.

The acrylic resins of, theaboveY typesare' polymers of acrylic acid; methacrylic acid; alkyl acrylates or alkyl methacrylates, the alkyl moieties of which'este'r's may have widely varying chain lengths; and/or acrylarni'desor methacrylamides. Acrylic'resin interpolymers within'these categories which are useful in the process of the present invention are disclosed, for example, inl U.S. Pats. Nos;

2,795,564;l 2,865,877; and 3,157,562, the disclosures er which are incorporated by reference herein.

The preceding acrylic finishes are customarilyy employed in conjunction with a lacquer or'v lacquer emulsion top coat for drying of the acrylic Ifilm. Such coats, which may additionally be formed in accordance' withfthe. method of the present invention, may' suitably utilizeV nitrocellulose dispersions such as Rohm and :Haas' Hydrholac WC-230 (or WC-300), Ortho-Clear: 260 (or 26l-D), or Chemical Coating Corporations Trans E series of coatings.

t The polyurethane resin finish coatings useful vin the present process comprise nitrocellulose lacquers 'of elas-` I Accordingly, vthe term finish coating as used herein corn-v leather substrate and the backing layer. Inventories of such individual finishing assemblies may thus be maintained by tanners, shoe manufacturers, or other users, and employed for finishing operations on demand. 'The present method may be employed, in the finishing of leather substrates of any suitable type. rl `hu's, finish coatings may be applied by the method of theinvention to leather skins; hides; die-cut leather pieces in various shapes, e.g., shoe uppers, quarters, tips, Vamps, straps, or lining quarters and vamps; all leather goods, e.g.wal lets, lkey cases, eyeglass cases, billfolds, handbags .or belts; garments; cut upholstery patterns, or the like.' It should be understood, therefore, that as used herein the terms leather substrates or leather pieces includevall such leather materials.

The method hereof ma'y also be utilized'to apply any conventional film-forming finishes to leather substrates. In particular, it can be used for the application ofeither the well known non-glazeA acrylic emulsion finish coatings or polyurethane resin finish coatings (employed the manufacture of patent or easy-care leathers). The acrylic emulsion finishes which may be applied by the method hereof (and which comprise the greatest prehends anyl such conventionalv film-formingwlfeather' finishing composition.

PREFERRED EMBODIMENTS 0E THE INVENTION The succesisve stages of a preferred embodiment of the present invention are illustrated in FIG. 1 of the drawing. As shown in Stage A thereof, leathersubstrates 11vt o be finished are placed between a backing or :supporting layer 12 and a release or transfer layer 13. 'Ihe supporting layer vhas a finish-receptive surface 14y which may, if desired, comprise an upper stratum or coating thereon. It is vsuitable to provide a ikraft paper for the supporting layer, which paper may be coated with an acrylic resin Transfer layer 13, on the other hand, is generally the` composite of a carrieri15, a permanent release stratum 1 6, and a releasable finish coating 17 thereon.l'l.`h elca'r' r ier 1 5 may suitably be a paper/or similar sheet material.

The permanent'Y release stratum 1 6 comprisesfa coating` of a material upon which a conventional finishing'cornpositionmay be releasably coated yetwhich will notitieg offset from the transfer layer upon transfer of .the finish-v ing composition to the ,leather substrates M11 andthe sup,v

porting layer 12 therefor. Polymethylsiloxane 'coatings may, 'for example, be Vutilized asthe permanent release stratum 1,6 of the transfer material. Alternatively, otherY siloxanes or other known release coatings may be similarly useful. Transfer layers found particularly satisfactory include those having a polysiloxane coating and commercially available from S. D. Warren Company under the designations Transcote Patent A, Stripkote Vel C 2S Gloveskin and Transcote ER.

The releasable finishing coating 17 may comprise any of the above noted leather finishing compositions. Such compositions normally adhere to the release stratum 16 on carrier 1S and are not offset therefrom when, for example, the layer is a continuous web and is rolled on itself. When, however, the layer is superimposed with the leather substrates and the finish-receptive surfaces of the supporting material and suicient heat and pressure are applied thereto, the finish coating is substantially entirely transferred or offset from release stratum 16 to the last mentioned surfaces.

Superimposition of the respective layers in a sandwichlike assembly is illustrated in'Stage B of FIG. 1. The releasable finish coating 17 of the transfer layer is thus pressed against both the outer surfaces of the leather substrates 11 and the adjacent, juxtaposed finish-receptive surface 14 of the supporting layer 12. The superimposed layers are simultaneously squeezed together and heated to effect transfer of the finish coating. Preferably, the respective layers are heated to temperatures of from about 150 to 200 C. and squeezed together to effect transfer of the finish composition.

As shown in Stage C of FIG. l, the supporting layer 12 and carrier 15 are thereafter separated. The finish coating is thus transferred to the leather substrates 11', forming coatings 18 and 18a thereon and being offset onto the juxtaposed surfaces 21a, 2lb and 21e of the supporting layer 12. Substantially all of the finish coating 17 is thus transferred from layer 13 to the juxtaposed surfaces of the leather substrates and the finish-receptive transfer layer.

A preferred form of apparatus for vcarrying out the present method by a continuous operation is schematically illustrated in FIG. 2 of the drawing. As shown therein, the supporting layer 12 is fed as a continuous web from a feed roll 22 into contact with the transfer layer 13 fed from a feed roll 23. The respective continuous webs may be fed over suitable idler rolls, such as rolls 24 and 25. The leather substrates 11 to be finished lare intermittently fed onto the continuous web 12, thus forming the assembly illustrated in Stage A of FIG. 1. v The superimposed layers are thereafter fed into the nip of rolls 26 and 27, the former of which is a heated steel roll and the latter of which is an adjustable pressure roll. These rolls squeeze the several layers into the sandwich-like assembly illustrated in Stage B of FIG. l, subjecting the same to sufficient heat and pressure to offset the finish coating from the transfer web to the leather substrates and the supporting web therefor. In the preferred embodiment shown, the heated roll 26 contacts only the transfer web 13. In this manner, undue heating and consequent damage of either the leather substrates 11 or the paper-supporting web 12 is avoided.

The web assemblage is thereafter passed over a support roll 28, which may be used to adjust the tensionron the transfer web, and the latter is stripped from the assembly and wound on a rewind roll 29. The assembly removed from the support roll corresponds to that shown in Stage C of FIG. 1 of the drawing. The stripped transfer web or release paper, designated 13 in FIG. 2, may thereafter be removed from roll 29, re-coated with additional finish, and mounted on feed roll 23 for further finishing operations.

After thus coating the finish upon the leather substrates the supporting web carrying the same is passed through the nip of a further heated roll 31 and adjustable pressure roll 32. The finish layer upon each leather substrate is thus ironed to impart the required gloss and hand to the leather. The thus coated and cured finished leathers, designated 11', are removed from the supporting'web, and

the latter, illustrated at 12', is wound up on a take-up roll 33.

IEmploying the continuous system described hereinabove'the finished leathers may readily be stripped from the supporting web without leaving any residual or frayed edges or flashing from the finish coating adhering to the edges of the coated leather surfaces. To the contrary, it has been found that finish layer breaks evenly along the edges of the leather, providing a uniform coating which does not require any trimming and leaving the balance of the finish on the kraft paper supporting web. After winding up the latter, the web may be discarded or suitably treated for recovery of the excess finish coating.

When, on the other hand, it is desired to individually finish leather substrates in a batch-wise manner, a finishing assembly such as illustrated in FIG. 3 is preferably employed. Such assembly incorporates an individual discrete backing layer 120 and release layer `130, which have areas of the same order of magnitude as the leather substrate to be finished therewith and possess substantially the same dimensions. The sheets and 130 are secured to one another along an abutting edge of each layer by any suitable means, as by folding over or hinging the margin 22 of the supporting layer 120 and cementing, stapling or otherwise securing the same to the corresponding margin of layer 130. In this manner, the discrete sheet materials may readily and economically be utilized to provide a finishing assembly into which the leather substrates 110 may be inserted and with which they may be finished.

The respective sheet material layers 120 and 130 may have the same structure and composition as supporting and transfer layers 12 and 13, respectively. Thus, the

release layer may comprise a permanent release Y stratum and a releasable finish coating 170 corresponding in composition, respectively, to strata 16 and 17 of transfer layer 13 shown in FIG. l.

The finishing assembly of FIG. 3 is employed in the samemanner as illustrated in the successive stages of FIG. 1. The plural layers of the assembly are pressed together and, desirably, heated by merely being fed between a pair of rolls such as rolls 26 and 27 of the apparatus embodiment shown in FIG. 2. It will however, be understood that the assembly of FIG. 3 may be used in connection with any device having a pair of nip rolls and need not have any associated winding or unwinding equipmet such as is involved in the apparatus shown in FIG. 2.V IUse of the batch-wise finishing assembly of FIG. 3 i s particularly advantageous when it is desired to finish relatively srnall, pre-cut leather pieces such .as shoe uppers. Moreover, leather finishing may be carried out employing this embodiment of the invention employing relatively simple and inexpensive equipment and with relatively increased ease of handling. Finally, use of previously prepared finishing assemblies incorporating any desired finish coatings provides improved flexibility and control of leather finishing operations.

The following examples relate to specific embodiments of the method of this invention carried out continuously in connection with an apparatus of the type illustrated in FIG. v2 (Examples 1-12), or batch-wise employing the finishing assembly shown in FIG. 3 (Example 13). In the examples all parts and percentages are given by volume and all temperatures in C., unless otherwise indicated.

EXAMPLE 1 Abrown kraft paper web (50 weight) is coated with 8 cc./ft.2 of an adhesive coating consisting lof the following:

j Parts Aqueous emulsion of an intermediate hardness, high molecular weight, acrylic polymer having adhesive characteristics, of the type disclosed in U.S. Pat. No. 2.795,564, the emulsion having a solids content ofv 46% by weight, a pH of 9.7 and a density of 8L9 lbs/gal. (Rohm and Haas Primal AC 34) 25 The epidermic (grain side) of the leather hides to be finished is coated with 12 cc./ft.2 of the same adhesive pre-coat and the leather substrates placed on the supporting web for finishing.

A further continuous transfer or release web having finish-receptive polysiloxane outer surfaces (S. D. Warrens Stripkote Vel C 2S Gloveskin) is coated with a finish coating deposited from the following solution:

Parts Nitrocellulose emulsion of a plasticized polyacrylate incorporating a spirit-soluble dye, a sulfonated castor oil, and a high boiling solvent, and having a solids content of about 4.9% by weight (Chemical Coatings Co. Trans E 1688) 400 Clear nitrocellulose emulsion of a plasticized polyacrylate incorporating a sulfonated castor oil and a high boiling solvent (Chemical Coatings Co. Clear Slip 1230) Aqueous nitrocellulose emulsion of a relatively soft,

high molecular weight amide-containing copolymer of lower alkyl methacrylates, the emulsion having a 35% by weight solids content, a pH of 2.6-3.0 and a density of 8.5 (Rohm and Haas "Primal HA-65) Water The finish coating is applied to the transfer web and the web is thereafter dried, e.g., by forced air drying at 160 C. forv 3 minutes, after which it is cooled to provide a finish layer approximately 0.5-0.75 mil thick on one face of the transfer web.

The thus coated transfer web 13 and supporting web 12 are passed through pressure rolls 26 and 27, as shown in FIG. 2, the composite assemblage being heated at a temperature of 150 C. for about two seconds. The finish coating is thus stripped from web 13 and deposited on the juxtaposed surfaces of the leather substrates 'and the intermediate portions of the supporting web 12. The remaining transfer paper web 13 is then rewound on roll 29 for recoating.

Supporting web 12 bearing the coated leather substrates 11 is then passed betweenthe pressure rolls 31 and 32, wherein it is heated to 15G-200 C. for about 2 seconds. The polyacrylate coating is thus smoothed and ironed and a desired final gloss imparted to the coated leather` The leather substrates are thereafter strippedfrom the supporting web and the finished leathers removed without the formation of any residual frayed coated edges.

EXAMPLE 2 p Example 1 is repeated utilizing the following composition for forming the finish coating on the transfer web:

, Parts Aqueous nitrocellulose emulsion of an acrylic polymer having a solids content of 13% by weight, a pH of 6.0-7.0, and a density of 7.64 lbs/gal. (Rohm and Haas HydrholacfWC-230) 40 A spirit soluble dark brown dye having a density of 7.15 lbs./gal. and being compatible with both water and organic solvents (Rohm and Haas M LS-` 3004) ll` 40 v Parts Anaqueous emulsion of an intermediate hardness, high molecular weight acrylic polymer, of the type disclosed in U.S. Pat. No. 2,865,877, the emulsion having a solids content of 20% by weight and a density of 8.6 `lbs./ gal. (Rohm and Haas Primal B-sfm 10 An aqueous emulsion of a soft, fine particle size, high molecular weight acid-containing lower alkyl acrylate polymer, the emulsion having a solids content of 46% by weight, a pH of 6.1-6.7, and a density of 8.84 lbs/gal. (Rohm and Haas Primal LT- 87) 1o Sulfonated castor oil (Atlas 152 oil) 5 Water 5 The overall coating composition has a solids content of approximately 10% by weight.

Upon transferring the aforesaid finish to leather substrates inthe manner described in Example l, similar acrylic finishes are formed thereon.

EXAMPLESv 3-10 Leather finishes are applied in accordance with the procedure described in Example l, by thetransfer of finish layers formed from each of the following coating compositions An aqueous emulsion of a high molecular weight,

self-cross-linking acrylic polymer, of the type disclosed in U.S. Pat. No. 3,157,562, the emulsion having a solids content of 46% by weight, a pH of 2.8-3.6 and a density of 8.8 lbs/gal. (Rohm and.

Haas Primal E-32) 10 Primal B-88 10 EXAMPLE 6 Parts Trans E 1688 30 Primal E-32 An organic phosphate-surfactant solution for promoting uniformity of coating and penetration of the finish into leather substrates, having a solids content of 20% by weight and a density of 8.3 lbs./

gal. (Rohm and Haas Primal Leveler Ma-65) A 5 Water 10 EXAMPLE 7 lParts Primal Brown 40 Primal E-32 20 Primal B-88 10 Hydrholac WC-230 .f 30 Water ozs. by weight of dye per gallon of water] -1 40 Primal B-SS 10 An aqueous clay/wax filler having a solids content of 19% by weight and a density of 9.4 lbs/gal.

(Rohm 'and Haas Primal Filler 1) 2O 1Of solution.

EXAMPLE 9 Parts TiOz in the rutile form (Rohm and Haas Primal White 1687) 40 Primal B-l 30 Primal B-88 5 Water 5 EXAMPLE 10 Parts Primal -E-32 25 Primal AC-34 25 LS-3004 5 Water 20 EXAMPLE 11 When completely cross-linked acrylic polymer finish coatings are desired, the coating 17 formed on release stratum 16 and thereafter transferred in accordance with the present invention is preferably formed bythe appli. cation of a two stratum coatings. Compositions which may be utilized in forming the initial stratum `of. such a coating include the following:

A v Parts Hydrholac WC-230 40 LS-3004 20 Primal B-88 `l0 Trans E 1688 40 Primal HA-65 5 Water 10` Nitrocellulose solution (Rohm and Haas Ortho- Clear 260) Y20 Di-isobutyl Ketone 20 TiOg pigment (Rohm andvHaas Orthochrome'Whlte #319) l J 4 Oil-modified alkyd plasticizer solution (Rohm andV After application of the initial stratum such is dried, e.g., at 100 C. for two minutes, and a second stratum deposited thereon formed, for example, from either of the following compositions: i

The second stratum is then dried, e.g., at 170 C. for three minutes, to cross-link the acrylic resin,and the transfer coating 17 thereafter transferred `to'leather `substrates as described in Example l above. A

EXAMPLE l2 :Further leather finishes are applied in accordance with Example 1, by the transfer of polyurethane finish coat- 10 ings formed by application of the following formulation to release stratum 16:

Parts Nitrocellulose-polyurethane elastomeric lacquer incorporating methyl ethyl ketone as a solvent and having a density of 8.07 lbs./ gal., a viscosity of 30 G-H sec. and containing 40% by weight non-volatiles (Polyurethane lacquer XP-2085 distributed by Spencer Kellogg Division of Textron Inc.) 2 Toluene 2 Methyl ethyl ketone 4 After drying at C. three minutes, the coating is transferred as described hereinabove.

EXAMPLE 13 A finishing assembly of the type illustrated in FIG. 3v

is prepared as follows:

Initially,'a release layer is provided by the successive coating of a release paper having a finish-receptive polysiloxane outer surface (S. D. Warrens Transcote ER) with the following finish mixes:

Parts Aqueous nitrocellulose emulsion of an acrylic polymer (Rohm and Haas Hydrholac WC300) A self-crosslinking acrylic emulsion (Rohm and Haas E-760) 3 Aqueous wax dispersion (Rohm and Haas Primal The preceding coatings are successively applied and dried lto form a film of from 0.5 to 0.75 mil on the polysiloxane outer surface. A coated roll of such material is then slit into any desired width, e.g., from l0" to 4', for forming the finishing assemblies. A kraft paper backing layer isprepared from an appropriate roll source, the web being slit approximately 1" wider than the coated release paper and the 1" overlap being folded over the margin of the coated release paper and glued along the abutting edge as at 22 in FIG. 3 to provide a hinge-like assembly. Such assembly is then cut into varying lengths, e.g., from`12" to 7', depending upon the size of the leather substrates to be finished, and the finishing assemblies thus completed.

Each leather substrate to be laminated is then precoated with a suitable adhesive (e.g., the adhesive precoat described in Example 1, or a similar adhesive containing van acrylic adhesive such as Primal LT-87 or E-826) and inserted into the finishing assembly. The assembly is fed through a nip roll device to apply the desired heat and pressure to the superposed strata and effect the desired transfer of the finish coating. Good results are obtained when one roll is heated to about 30G-400 F. with a line pressure of about 80-150 lbs. per linear inch, the other pressure roll having a durometer of about 40-60.

The sandwich fed through the roll is thereafter opened, the leather substrate to which the finish coating has transferred is removed, and the remaining backing and release layers are discarded. The coated leather is then fed through the same nip rolls or other pressure rolls (e.g.,

rolls 31 and 32 as described in Example 1) to complete the cure of the finish coating if necessary and ,toy iron and impart the desired final gloss to the finish.

The preceding examples illustrate preferred techniques and compositions which may be employed in accordance with the method of the present invention.v -It, will, of course,1be understood that the method may be otherwise carried` out, e.g.', by leffecting the transfer of the -fnish coating between 'platens rather than between squeeze rolls. Since these or other changesrmay be made in such compositions and/or in the parameters of the methods described hereinabove without departing yfromwthe scope of the invention, it isrintended that the preceding` de cription should not be construed inalimiting sense'.

I claim: y

, -1. An article for the finishing of leather, which comprises a pair ofy discrete sheet material'layershaving s'ubstantially the same major dimensions'and beingsecured tofone another along an abutting' edge of each saidv layer, thefirst of said layers comprising a backing layer :having a finish-receptive surface thereon and the second of said layers comprising a release layer having v'a releasable leather finish coating, and said layers being capable of being pressed into a sandwich-like assembly with the finish-receptive surface and the releasable leather finish coating facing one another with av leather substrate to.A be finished interposedtherebetween to transfer thel finish coating from the release layer to the juxtaposed surfaces of the leather substrate and the backing '.layer;

2. The article of claim 1, wherein said release .layer comprises a release paper having a nish-receptivesfpolysiloxane outer surface, and wherein the releasable leather finish coating is coated on said surface.

3. The article of claim 1, wherein the leather finish coating of said release layer comprises an acrylic resin finish coating.

4. The article of claim 3, wherein theV leather'iinish coating is provided by the succcsive coating of a nitrocellulose emulsion and an acrylic resin emulsion on-a release paper. f z :rv

5. An article for the nishingof leather, which comprises a pair of discrete paper sheets having substantially the same major dimensions and being secured to one -another along an abutting .edge of-eachsaid sheet, one of said sheets 'comprising a release paper having .a finish-receptive polysiloxane outer surface andtbearing a ,releasable acrylic resin leather finish coating on saidsurfaeeaid sheets -being capable ofvbengpressed into a. ,sandwich' like assemblyl with the releasable vacrylic :resin v leather finish coating on .said.-.one sheet facingtheother .sheet with a leather substrate to be finished interposed therebetween to transfer said .,'liiSh coating froinsaidolne sheet to the juxtaposed surfaces of the leather substrate andsaid other,sheet, y, v.; 1,., 6. The article of cla' 5, wherein, the releasable leather finish coating on said one sheet is: provided ,by the successive coating of a nitrocellulose emulsion'and an acrylic resin emulsion on said sheet. v 'l Referencesl vCited UNITED STATES PATENTS v l 51,843,739 schubert 1527,15

2/ 1932 11,955,562 4/1934 POschel 15G- .237 11,993,523, 3/ 1935 Pschel 8,2."5 2,029,377 2/1936 Kap1an, 161-226 X 2,126,321 8/ 1938 Freudenberg et al.

2,606,853 l8/1952 Reese et al. e t- 16'1-2081X 3,045,376 7/1962 Levinsohn Y 161--226v 'X v3,276,933 10/1966 vlBrant 161--406 X 3,473,990 v10/ 1969 Simon et al. 16T-226 X 6,519,456@ -7-/ 1970 Reed etV al. 156-240 X' ALFRED L. LBAVITI, Primary Examiner l T. E. BOKAN, Assistant Examiner U.S. Cl. X.R.

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