WO2001032938A1

WO2001032938A1 - A transfer member for imparting a finish leather

Info

Publication number: WO2001032938A1
Application number: PCT/IN1999/000058
Authority: WO
Inventors: Pushpinder Kumar Kaushik
Original assignee: Max India Limited
Priority date: 1999-11-01
Filing date: 1999-11-01
Publication date: 2001-05-10
Also published as: CN1177941C; DE69920535T2; EP1266040A1; CN1375014A; HK1047962B; ATE277201T1; TR200201184T2; HK1047962A1; DE69920535D1; EP1266040B1

Abstract

A transfer member for imparting a finish to leather. The transfer member has at least a gloss film supported on a carrier so as to impart a gloss finish to leather. The transfer member may additionally comprise a foil on said film, said foil being either a colour, print or metallized.

Description

A TRANSFER MEMBER FOR IMPARTING A FINISH LEATHER

This invention relates to a transfer member for treatment of leather so as to impart gloss properties thereto.

PRIOR ART

It is generally known that hide is subjected to a chemical treatment to produce leather. However, if an appearance or finish is required, it was hitherto necessary to subject leather to an additional step of chemical treatment so as to impart a gloss appearance. 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 split 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 chemical adhering to the plate.

OBJECTS OF THE INVENTION

An object of this invention is to propose a transfer member for treatment of leather and so as to impart gloss properties thereto.

Another object of this invention is to propose a transfer member for treatment of leather and so as to provide a uniform feel to leather.

Still another object of this invention is to propose a transfer member for treatment of leather and which provides good plate releasing properties.

Yet another object of this invention is to propose a transfer member for treatment of leather and which provides a good sealing of fibers.

A further object of this invention is to propose a transfer member for treatment of leather and which provides grain flatness.

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

DESCRIPTION OF INVENTION

According to this invention there is provided a transfer member for imparting gloss properties to leather comprising a gloss film of at least two co- extruded layers and, wherein, the inner layer is the active or gloss layer and the outer layer is a colayer, a carrier or substrate layer releasably held to said outer layer.

The gloss film preferably comprises three coextruded layers and wherein the inner layer has the gloss properties, an intermediate layer is the colayer which contributes to the bulk properties of the film and further is a storage layer for the migratory chemicals, and an outer layer which is a colayer. A carrier such as paper is adhered to the outer layer.

The inner layer comprises a resin layer of isotactic polypropylene singularly or in combination with random ethylene propylene copolymer present in an amount of 0 to 40% by weight. The intermediate layer comprises isotactic polypropylene and migratory additives, which are antistatic and slip agents. The outer layer also comprises isotatic polypropylene with an additive, which is an antiblock agent. A stiffener such as paper is adhered to the outer layer by means of an adhesive.

The inner layer may additionally comprise migratory chemicals present in the amount of 0-5%, migratory chemicals being antistatic and slip agents selected from erucamide stearamide, silicon oil, stearic acid and stearates used singularly or in any combination thereof. Further, the inner layer may comprise an antiblock agent present in the amount of 500-4000 PPM. The antiblock agents are selected from silica, silicate, clay, talc and quartz comprising singularly or in any combination thereof. The haziness or glossy- ness of the inner layer is varied by changing the thickness of the inner layer and quantity of migratory chemicals and antiblock agents in the composition.

The migratory chemicals comprising said antistatic and slip agents are present in the amount of 500- 10000 PPM by weight in the intermediate layer. The outer layer is identical to the inner layer and comprises isotatic polypropylene in combination with rendom co-polymer of ethylene propylene, and where ethylene propylene is present in the amount of 0 to 40% by weight. The film further comprises a paper layer adhered to the outer layer. The paper layer is a cellulosic paper such as cromo art paper and

2 having a granrmage of 30 to 100 gms/m .

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 230°C/2.16 kgs 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 film having three layers, the antiblock agent may or may not be provided in the outer layer. In accordance with another embodiment, an antiblock agent is provided in the outer and in the inner layer. The outer layer may be subjected to a corona treat- ment, flame treatment or chemical treatment so as apply an adhesive thereon to secure a paper layer therewith. The paper layer acts as a stiffener and absorbs excess heat during the plating of the leather.

The transfer member of the present invention has a thickness of 8 to 45 microns. If the thickness 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 thickness is less than 8 microns, the required quality and properties are then not achieved. Both the inner and outer layers should have sufficient thickness in the instance of two layers film, in order to store and release the chemicals therefrom. Similarly, the inner, intermediate and outer 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 transfer member has a thickness of 12 to 45 microns.

The inner and intermediate 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 gloss would reduce. If the thickness is more than 8 microns, and the outer, intermediate and inner layers are extruded then problems may arise in the coextrusion of the 1 ayer s .

In the following table the properties of the gloss film are given in comparison with the predetermined speci f icat ions .

COMPARISON PROPERTIES OF GLOSSY FILM

S.No. PROPERTIES UNIT SPEC ACTUAL SPEC ACTUAL

RESULTS RESULTS

1. AVG.GAUGE MICRONS 15 14.9 20 20.1

2. HAZE % 1.5 1.2 1.5 1.3 (MAX) (MAX)

3. GLOSS 95 98 95 97 (MIN) (MIN)

4. COEFFICIENT OF FRICTION STATIC 0 . 55 0.50 0.45 0.56 DYNAMIC 0.55 0.48 0.55 0.54 5. SHRINKAGE MD % 4.0 3.5 4.0 3.0

TM % 2.0 1.0 2.0 0 . 5 (MAX) (MAX)

TREATMENT DYNES/CM 38 40 38 40 (MIN) (MIN)

Reference has been made hereinabove to a transfer member comprising only the gloss film on a carrier or substrate. The transfer member of the present invention also envisages a transfer member having a foil in addition to the gloss 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 gloss ilm, the foil being provided on said film.

In each instance, the foil comprises of a plurality of layers with at least an outermost layer being an adhesive layer adapted to contact the leather surface, an 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 onto 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 feelmodifier 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 microcrys tal lene 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. 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 pi as t icizer s . 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 embodi- ment, the natural resin may be present with the synthet i c 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.

Claims

WE CLAIM:

1. A transfer member for imparting gloss properties to leather comprising a gloss film of at least two coextruded layers and, wherein, the inner layer is the active or gloss layer and the outer layer is a colayer, a carrier or substrate layer releasably held to said outer layer.

2. A transfer member as claimed in claim 1 wherein said gloss film comprises three layers being said inner layer, an intermediate layer and said outer 1 ayer .

3. A transfer member as claimed in claim 1 wherein the inner layer comprises isotatic polypropylene alone or in combination with random ethylene propylene 5 co-po 1 yme r present in the amount of 0 to 40% by weight, and optionally additives being antistatic and slip agents present in an amount of 0 to 5% by wt . , and optionally a further additive being an anti block agent present in an amount 500-4000 ppm by o weight of isotatic polypropylene.

4. A transfer member as claimed in claim 2 wherein the intermediate layer comprises isotatic polypropylene and said additives present in the amount of 500-10000 PPM by wt . of isotatic polypropylene.

5 5. A transfer membe r as c 1 a imed in claim 1 whe re i n the outer layer comprises isotatic polypropylene alone or in combination with randon ethylene propylene copolymer .

6. A transfer member as claimed in claims 1 to 5 0 wherein said antistatic and slip agents are selected from erucamide stearamide, silicon oil, stearic acid and stearates used singularly or in any combination thereof, said antiblock agents selected from silica, silicate clay, talc and quartz singularly or in any combination thereof.

7. A transfer member as claimed in claim 1 wherein the thickness each of said inner and outer layer is 2 to 8 microns .

8. A transfer member as claimed in claim 1 wherein the thickness of said member is 8 to 45 microns.

9. A transfer member as claimed in claim 1 comprising a foil provided on said film, said foil selected from a print, colour or metallized foil.

10. A transfer member as claimed in claim 9 wherein 5 each of said foils comprise a plurality of layers with at least 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 there- o between, and wherein the active layer is either a print, colour or metallized layer.

11. A transfer member as claimed in claim 10 wherein the print and colour foil has each a feel modifier 5 layer comprising a plurality of layers and wherein one of the layers is a feel modifier layer and the other layer is a top coat layer or a cover coat layer.

12. A transfer member as claimed in claim 10 wherein the print and colour foil has each a feel modifier 0 layer comprising a plurality of layers and wherein one of the layers is a feel modifier layer adjacent to the release coat, a top coat layer adjacent to the feel modifier layer, and a cover layer adjacent to the top coat layer.

13. A transfer member as claimed in claim 10 wherein the metallized foil includes a top coat layer on said release coat layer.

14. A transfer member as claimed in claims 11 and 12 wherein the feel modifier comprises a combination of or only a single wax such as mi crocrys tal 1 ene wax, paraffin, natural or synthetic waxes in solution or emu 1 s i on form.

15. A transfer member as claimed in claims 11 and 12 wherein the feel modifier layer also comprises oils used singularly or in combination with polydialkyl siloxane, olein modified siloxanes, dieth- ylene modified silicon oils, epoxy modified silicon oils alcohol modified silicon oils.

16. A transfer member as claimed in claims 11 and 12 wherein the feel modifier layer comp rises comb i na- tion of waxes and lubricants of separate layers of waxes and lubricants.

17. A transfer member as claimed in claim 11 to 13 wherein the top coat layer comprises lacquer and lacquer emulsions of various resins, such as nitrocellulose copolymer of vinyl chloride and vinyl acetate, polyurethane and polyamides with or without cross linking agents with or without fillers, such as si 1 ica.

18. A transfer member as claimed in claims 11 and 12 wherein the covering coat layer comprises essentially of natural resins such as shellac, caesin, albumin and gelatene or pi as t ici zer s .

19. A transfer member as claimed in claims 11 and 12 wherein the covering coat layer comprises synthetic resins such as acryliclic, methacrylic, synthetic rubber, vinyl resin, nitrocellulose resins or polyurethane or a combination of said natural and synthetic resins.

20. A transfer member as claimed in claims 11 and 12 wherein the covering coat layer may also include coiourents with or without dispersing agents, with or without cross linking or curing agents.

21. A transfer member as claimed in claim 13 wherein a print coat layer is provided between said metallized layer and top coat layer.