Title of Invention

"A PROCESS FOR PREPARATION OF A TRANSFER FOIL FOR LEATHER APPLICATIONS."

Abstract

This invention relates to a transfer foil for leather treatment applications. The transfer foil has a release coating provided on a paper or release film support. A feel modifier layer with or without top protecting coat layer is provided onto said release coating. A covering and/or colourant layer provided onto said feel modifier layer and an adhesive layer adapted to be in contact with the leather surface is provided onto said covering and/or colourant layer.

Full Text

This invention relates to a transfer foil for leather applications. To enhance the appearance, durability and feel of leather, a finishing treatment is imparted thereto. Such a finishing treatment known in the art comprises spraying of finishing chemicals onto the crust of the leather. Several distinct disadvantages are associated with the known process. One such disadvantage is that the spraying of finishing chemicals causes a pollution. Another disadvantage is that a consistency is not achieved due to uneven spraying of chemicals. Yet another disadvantage is that the process is time consuming and not cost effective. Therefore an object of this invention is to propose a novel transfer foil which imparts fullness to the leather. Another object of this invention is to propose a transfer foil which provides consistency and uniform treatment. Yet another object, of this invention is to propose a transfer foil which provides better cutting values in comparison to the known art. Still another object of this invention is to propose a process for preparation of a transfer foil which makes the treatment process less time consuming in comparison to that of the prior art. A further object of this invention is to a propose process for preparation of transfer foil which does not require any special machine or chemicals. According to this invention there is provided a process for preparation of a transfer foil for leather applications comprising steps of: (a) applying a release coating on a base support wherein said base support is selected from polyester and bi-axialy oriented polypropylene (BOPP) with or without paper and wherein the thickness of said release coat layer is between 1-3 GSM (grams per sq meter); (b) applying feel modifier layer with or without covering coating layer over the said release coat layer applied by step (a) wherein the said feel modifier layer has a thickness of 1-6GSM and comprises at least two layers selected from the two combinations, the first combination comprising a mixture of feel modifier as first layer and a top coat as second layer, the second combination being a feel modifier as first layer and a cover coat as second layer wherein feel modifier layer is selected from a single layer of wax or a combination of wax and lubricant or a separate layer of wax and lubricant and wherein the cover coat is selected from natural resins and wherein the top coat layer is selected from lacquer and lacquer emulsions of resins; (c) applying a colour coating on to the said feel modifier layer wherein colourent is used with or without dispersing agent, with or without cross-linking or curing agents and the colourant is selected from metallic pigments, pearl pigments of organic or inorganic nature or dyestuffs and wherein the thickness of colourant layer is between 3- 40 GSM; (d) applying an adhesive layer adapted to contact leather surface provided over the colour coating applied by step (c) wherein the thickness of adhesive layer between 2-15 GSM. In accordance with this invention the transfer foil for leather applications comprises a paper or release film support to have a release coating provided thereon. A feel modifier layer with or without top protecting coating layer is provided onto said release coating. A covering and/or colourant layer is provided on the feel modifier layer and an adhesive layer adapted to contact the leather surfaces is provided onto said covering/colourant layer. The feel modifier layer comprises a plurality of layers. According to an embodiment, the layer comprise at least two layers. One of said layers is a mixture of feel modifiers and a top coat or feel modifier and cover coat. The top coat layer is a protective coating for protecting the covering coat layer. The top coat layer consists of lacquer and lacquer emulsions of various resins, such as hitocellulose, copolymer of vinyl chloride and vinyl acetate, polyurethane with or without cross linking agents with or without fillers. The covering coat layer comprises essentially natural resins such as shellac, caesin, albumin and gelatene or plasticizers. Alternatively, the covering coat layer may be selected from natural resins or synthetic resins such as acrylic, methacrylic, synthetic rubber, vinyl resin, nitrocellulose resins or polyurethane. In accordance with another embodiment, the natural resin may be present alongwith the synthetic resin. A transfer foil according to a preferred embodiment of this invention is herein described and illustrated in the accompanying drawings wherein: Fig. 1 shows cross sectional view of the transfer foil. Referring to the? drawing particularly fig.i the transfer foil proposed by the present invention has a met/gloss base paper or a release film 1 having a release coating 2 provided thereon. A feel modifier coating 3 is provided onto said release coating 2 to provide a feel touch to the leather as required by the user. A covering and/or a colour coating 4 is provided onto said feel modifier layer 3 to provided the colour to the leather and finally an adhesive coating 5 adapted to contact the leather surface is provided onto the covering/colour coating 4. The feel modifer coating/layer 3 comprises & plurality of layers. According to an embodiments the feel modifier layer comprises atleast two layers. One of said layer is a mixture of feel modifiers and a top coat or feel modifier and cover coat. According to another embodiment the feel modifier layer comprises three layers namely a feel modifier layer adjacent to the release coat, a top coat layer adjacent to the feel modifier layer, and a covering layer adjacent the top coat. The feel modifier layer comprises a combination of or only a single wax such as microcrystallene wax, paraffin, natural or synthetic waxes in solution or emulsion form. The waxes incorporated in the feel modifier imparts a waxy feel to leather. According to an embodiment the feel modifier layer also comprises oils used singularly or in combination with polydialkyl siloxane, olefin modified siloxanes, diethylene modified silicon oils, epoxy modified silicon oils alcohol modified silicon oils. According to another embodiment the feel modifier layer comprises a combination of waxes and lubricants as this also improves the scuff resistance properties. It a waxy feel is required, then the content of waxes present in the feel modifier layer is greater than that of the lubricants. However, if a silky feel is required then the content of lubricants present in the feel modifier layer is greater than the waxes. The feel modifier layer can consist of a combination of waxes and lubricants, or separate layers of waxes and lubricants. The top coat layer is a protective coating far protecting the covering coat layer. The coat layer consists of lacquer and lacquer emulsions of various resins, such as hitocellulase, copolymer of vinyl chloride and vinyl acetate, polyurethane with or without cross linking agents with or without fillers. The covering coat layer comprising essentially of natural resins such as shellac, caesin, albumin and gelatene or plasticizers. Alternatively, the covering coat layer may be selected from natural resins or synthetic resins such as acrylic, methacrylic, synthetic rubber, vinyl resin, nitrocellulose resins or polyurethane. In accordance with another embodiment, the natural resin may be present with the synthetic resin. In accordance with yet another embodiment, the covering coat layer may also include colourents with or without dispersing agents, with or without cross linking or curing agents. The colourants may be selected from metallic pigments, pearl pigments of organic or inorganic nature or dyestuffs. A paper or release film as disclosed and claimed in the Patent Application No. 324/DEL/96 dated 19/2/1996 is provided to support said layers. In the instance of a film, a support, paper is provided for said film. The above coating are provided by the toro-gravure system to obtain different layers. The thickness of the release coating layer is in between 1-3 SMS(Grarn per square metre) (solid). The thickness of the feel modifier layer/top protected layer is 1-6 GMS (solid). The thickness of cover and colourant layer is 3-40 GSM (solid) and the thickness of adhesive layer is 2-50 GSM (solid). The transfer foil of the present invention has several advantageous applications, a few of which are enumerated hereinbelows i) for shoe uppers,lining garments, gloves, upholstery,leather articles such as bags, ii) for upgrading of poorer quality leather, iii) for treatment of splits, iv) to vary or modify appearance, v) to impart glossy or matt properties. WE CLAIM: 1. A process for preparation of a transfer foil for leather applications comprising steps of: (a) applying a release coating (2) on a base support (1) wherein said base support is selected from polyester and bi-axialy oriented polypropylene (BOPP) with or without paper and wherein the thickness of said release coat layer is between 1-3 GSM (grams per sq meter); (b) applying feel modifier layer (3) with or without covering coating layer over the said release coat layer applied by step (a) wherein the said feel modifier layer has a thickness of I-6GSM and comprises at least two layers selected from the two combinations, the first combination comprising a mixture of feel modifier as first layer and a top coat as second layer, the second combination being a feel modifier as first layer and a cover coat as second layer wherein feel modifier layer is selected from a single layer of wax or a combination of wax and lubricant or a separate layer of wax and lubricant and wherein the cover coat is selected from natural resins and wherein the top coat layer is selected from lacquer and lacquer emulsions of resins; (c) applying a colour coating (4) on to the said feel modifier layer wherein colourant is used with or without dispersing agent, with or without cross-linking or curing agents and the colourant is selected from metallic pigments, pearl pigments of organic or inorganic nature or dyestuffs and wherein the thickness of colourant layer is between 3-40 GSM; (d) applying an adhesive layer (5) adapted to contact leather surface provided over the colour coating applied by step (c) wherein the thickness of adhesive layer is between 2-15 GSM. 2. A process as claimed in claim 1 wherein feel modifier layer comprises three layers with a feel modifier layer as first layer, a top coat layer over the first layer as second layer and a covering layer over the second layer as third layer. 3. A process as claimed in claim 1 wherein wax is selected from microcrystalline wax, paraffin, natural wax, synthetic wax or any mixture. 4. A process ad claimed in claim 1 where said cover coat is selected from shellac, casein, albumin, gelatin, plasticiser or synthetic resins acrylic, methacrylic, synthetic rubber, vinyl resin, nitrocellulose resin or polyurethane, mixture of natural and synthetic resin. 5. A process ad claimed in claim 1 where said top coat layer is selected from nitrocellulose, co-polymer of vinyl chloride and vinyl acetate, polyurethane with/without cross-linking agents with/without fillers. 6. A process for preparation of a transfer foil for leather applications as substantially herein described.

Documents:

584-del-1996-abstract.pdf

584-del-1996-claims.pdf

584-del-1996-complete specification (granted).pdf

584-del-1996-correspondence-others.pdf

584-del-1996-correspondence-po.pdf

584-del-1996-description (complete).pdf

584-del-1996-description (provisional).pdf

584-del-1996-drawings.pdf

584-del-1996-form-1.pdf

584-DEL-1996-Form-2.pdf

584-del-1996-form-3.pdf

584-del-1996-form-4.pdf

584-del-1996-form-5.pdf

584-del-1996-form-6.pdf

584-del-1996-gpa.pdf