FIELD OF INVENTION This invention relates to a transfer member for treatment of leather so as to impart matt properties thereto.

PRIOR ART It is generally known that hide is subjected to a chemical treatment to produce leather. However, if a finish or appearance is required, it was hitherto necessary to subject leather to an additional step of chemical treatment so as to impart an appearance or finish. It would be apparent that such a known process had the disadvantage of an additional step of chemical treatment.

A further disadvantage of the known art is that associated with split leathers. In accordance with the known art, split leather was subjected to the step of lamination, pigmentation or transfer foil so as to upgrade or improve the quality of the leather. Thus, split leather is impregnated with binder and waxes so that when compressed a release takes place from the plate. After impregnation, it is then laminated, pigmented or treated with a transfer foil.

A disadvantage is that the fiber bundles do not get concealed and continue to be in a standing position.

Yet another disadvantage is that of the chemicals adhering to the plate.

OBJECTS OF THE INVENTION An object of this invention is to propose a novel

construction of a transfer member which may advantageously be employed for imparting a matt finish to leather.

Another object of this invention is to propose a transfer member for imparting a matt together with either a colour, print or metallised finish to leather.

Yet another object of this invention is to propose a transfer member for leather applications having suitable plate releasing properties.

Still another object of this invention is to propose a transfer member for leather applications having uniform feel property.

DESCRIPTION OF INVENTION According to this invention there is provided a transfer member for imparting matt properties to leather comprising a substrate or carrier to releasably support a matt film of at least three resins selected from ethylene propylene polymer, ethylene propylene butylene polymer, high density polyethylene, isotatic polypropylene and additives.

In accordance with one embodiment of this invention, the matt film comprises an inner layer being the active layer having the matt properties, and an outer layer being the colayer.

In accordance with another embodiment, the matt film comprises preferably of three coextruded layers and wherein the inner layer has the matt properties,

a middle layer being a colayer which contributes to the bulk properties of the film and further is a storage layer for the migratory chemicals, and an outer layer being a colayer.

As described hereinabove, the inner layer comprises a composition of atleast three resins selected from ethylene propylene polymer, ethylene propylene butylene polymer, high density polyethylene and isotatic polypropylene. The middle layer comprises isotatic polypropylene and additives being anti-static and slip agents. The outer layer also comprises isotatic polypropylene with antiblock agents. In the instance where the outer layer is a sealant layer, it may then comprise random copolymer of ethylene propylene where ethylene is present in the amount of 1 to 8 parts, and preferably 3 to 5 parts, of the copolymer.

The resin composition for the inner layer comprises 10-30% by wt. of ethylene propylene polymer, 0-50% by wt. of ethylene propylene butylene polymer, 25- 65% by wt. of high density polyethylene and 0-50% by wt. of isotactic polypropylene.

The composition for the inner layer may additionally include the additives present in the amount of 0- 5%. The additives are migratory chemicals such as antistatic and slip agents selected from erucamide stearamide, silicon oil, stearic acid and stearates used singularly or in any combination thereof.

Further, the additives for the inner layer may also comprise antiblock agent present in the amount of 500-4000 PPM. The antiblock agent is selected from silica, silicates, clay talc and quartz present

singularly or in any combination thereof. The haziness of the matt layer is varid by changing the thickness of the matt layer and/or quantities of additives in the inner layer composition.

The middle layer comprises isotatic polypropylene and additives. The additives are antistatic and slip agents and are present in the amount of 500-10000 PPM by wt. of the isotactic polypropylene.

The outer layer comprises isotactic polypropylene with antiblock agents as herein above mentioned.

In the instance where the outer layer is a sealant layer, it is then comprises random co-polymer of ethylene propylene where ethylene is present in the amount of 1-8 parts and preferably 3-5 parts of the co-polymer. The outer layer may also comprises ethylene propylene butylene polymer singularly or in combination with the aforesaid co-polymer.

The isotatic polypropylene present in the layers has an average molecular wt. of 25000 to 1,000,00, a melt flow index of 1-25 at 2°C and density of 0.892 to 0.92.

As herein described above an antiblock agent is provided in the outer layer. However, in the instance of a matt film comprising of only outer and inner layer, the antiblock agent may not be provided in the outer layer. In a matt film of outer, middle and inner layer, the anti block agent is preferably provided in the outer layer as well as in the inner layer. The outer layer may be subjected to the step of activation by a corona treatment, flame treatment or chemical treatment.

When the matt film has two layers only as hereinabove described, the outer layer comprises of isolatic polypropylene and that the migratory agents are present in the layer.

Reference is made hereinabove to a matt film comprising two or three distinct layers. However, in accordance with another embodiment, the matt film does not contain distinct layers, and the matt film is formed from a single mix of said resins and additives, which is then extrusion coated on said substrate or carrier.

The matt film of the present invention has a thickness of 8 to 45 microns. If the thickness of the film is greater than 45 microns, it does not affect the workability or properties of the film, but no advantages are derived therefrom and only adds to the end cost of the film. If the film thickness is less than 8 microns, the required quality and properties are then not achieved. Both the outer and middle layers should have sufficient thickness in the instant of two layers film, in order to store and release the migratory chemicals therefrom.

Similarly, the outer, middle and inner layers should have sufficient thickness in an three layers structure for storage and release of said chemicals. Preferably, and without implying any limitation thereto the matt film has a thickness of 12 to 30 microns.

The outer and inner layers have each a thickness of 2 to 8 microns and preferably a thickness of 2 to 5 microns. If the thickness of the inner layer is less than 2 microns, then haziness would reduce.

If the thickness is more than 8 microns, and the

outer, middle and inner layers are extruded then problems may arise in the coextrusion of the layers.

Reference has been made hereinabove to a transfer member comprising only the matt film on a carrier or substrate. The transfer member of the present invention also envisages a foil in addition to the matt film, said foil being selected from a colour, print or metallized foil.

In such an embodiment the transfer member comprises a carrier or substrate having the matt film, the foil being provided on said film.

The structure of the foil depends as to whether colour, print or metallized properties are to be imparted to the leather surface, and that separate foils are provided for each property.

In each instance, the foil comprises at least a plurality of layers with an outermost layer being an adhesive layer adapted to contact the leather surface and inner most layer being a release layer in contact with the film and an active layer provided therebetween, and wherein the active layer is either a print, colour or metallized layer.

The colour foil further comprises a feel modifier layer with or without top protecting coat layer on said release coating, said colorant layer provided onto said feel modifier layer.

In the instance of a metallized transfer foil, the intermediate layers comprise a top coat layer on said release layer, said metallized layer being

provided on said top coat layer to provide metal finish to the leather.

The print foil intermediate layers comprise a feel modifier layer provide onto said release layer, a print coat layer provided onto said feel modifier layer. A top coat layer may or may not be provided on said feel modifier layer.

The feel modifier layer in itself comprises a plurality of layers. According to one embodiment, 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 layer, a top coat layer adjacent to the feel modifier layer, and a covering layer adjacent the top coat layer.

The feel modifier layer comprises a combination of or only a single wax such as microcrystallene wax, araffin, 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.

If 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 for protecting the covering coat layer. The coat layer consists of lacquer and lacquer emulsions of various resins, such as nitrocellulose copolymer of vinyl chloride and vinyl acetate, polyurethane and poly- amides with or without cross linking agents with or without fillers, such as silica.

The covering coat layer comprises essentially of natural resins such as shellac, caesin, albumin and gelatene or plasticizers. Alternativelly, 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.

In the instance of a colour foil, the structure of the foil comprises an outermost layer of adhesive adapted to contact the leather receiving surface, a covering and/or colourant layer is contact with said adhesive layer, a feel modifier layer with or without top protecting coat layer, in contact with said covering and/or colorant layer and an release layer in contact with said feel modifier layer. Such a colour foil is provided with the matt film.

In the instance of a metallized foil, the structure of the foil comprises an outermost adhesive layer adapted to contact the leather surace, a metallized layer in contact with the adhesive layer, a top coat layer in contact with said metallized layer, a release layer in contact with said top coat layer, said matt film in contact with the release layer.

The metallized layer is provided onto the top coat layer by passing the transfer foil through a vacuum chamber and vapours of the metal get deposited thereon. The thickness of the metal layer depends on the temperature of the molten metal and vacuum chamber, the processing roll temperature and the optical density of the metal coating. Preferably the thickness of the metal layer is 1.8-2.5 optical density.

In the instance where scuff resistance properties are required, waxes and/or lubricants may be added to the top coating layer, but only for the purposes of imparting scuff resistance and not feel properties.

Alternatively such waxes and/or lubricants may be added to the release coat.

In accordance with another embodiment a separate scuff resistance, wet rub and dry rub fastness coat layer may be provided between said top coat layer and release coat layer.

The present invention envisages yet another embodiment of a transfer foil having a print coat layer between said metallized layer and top coat. The print coat layer comprises any pattern or design of a single or multicolours. Printing pigmented lacquers may be employed.

In the instance of a print foil, the structure of the foil comprises an outermost adhesive layer adapted to contact the leather surface, a print coat layer in contact with the adhesive layer, a feel modifier layer with or without covering coat layer in contact with the print layer, a release layer in contact with the feel modifier layer, said matt film in contact with the release layer.

According to another embodiment, the print coat layer is combined with the adhesive layer.

The print coat comprises pattern or design of a single or multicolours. Printing pigmented lacquers may also be employed.

The thickness of the release coating layer is in between 1-3 GMS (Gram per square meter) (solid).

The thickness of the feel modifier layer/top protected layer is 1-6 GMS (solid). The thickness of active coat layer is 1-5 GSM GSD (solid) and the thickness of adhesive layer is 2-50 GSM (solid).

In the following examles the composition prepared for the outer/matt layer is illustrated.

EXAMPLE 1 70 parts of isotatic polypropylene, 20 parts of ethylene propylene polymer, 10 parts of high density polyethylene and 2 parts of silica were taken in a container of a homogeniser and the contents were mixed with each other to get a homogenous blend.

A matt film by using the above composition as a matt layer was manufactured in the conventional manner by using abiaxially oriented polypropylene plant.

The following properties were found.

1. Thickness-19 microns 2. Film density-. 91 gm/cc 3. Haze (minimum)-40% 4. Gloss (maximum)-40% 5. Tensile strength i) Machine Direction-1100 kg/sq. cm ii) Transverse Direction-2200 kg/sq. cm 6. Useful Heat Range-115° to 145°C (5. 2 bar, 1 sec).

EXAMPLE 2 40 parts of isotatic polypropylene 5 pars of ethylene propylene polymer, 6 parts ethylene propylene butylene polymer, 49 parts of high density polyethylene and 1.2% additive (erucamide) were taken in a container of a homogeniser and the contents were mixed with each other to get a homogenous bland. A matt film by using the above composition as a matt layer was manufactured in the conventional manner by using biaxially oriented polypropylene plant.

The following properties were found.

1. Thickness-25 microns

2. Film density-0.9 gm/cc 3. Haze (minimum)-80% 4. Gloss (maximum)-15% 5. Tensile strength i) Machine Direction-1100 kg/sq. cm ii) Transverse Direction-2200 kg/sq. cm 6. Useful Heat Range-115° to 145°C (5. 2 bar, 1 sec).