WO2011149370A1

WO2011149370A1 - Cork fabric and process for the production thereof

Info

Publication number: WO2011149370A1
Application number: PCT/PT2011/000018
Authority: WO
Inventors: Carlos Alberto Mendes PINTO DE SÁ
Original assignee: Dyn Cork - Technical Industry, Lda.
Priority date: 2010-05-25
Filing date: 2011-05-25
Publication date: 2011-12-01

Abstract

A malleable and mouldable cork fabric based on a natural or agglomerated cork matrix is disclosed. The cork fabric comprises a first layer made of the natural or agglomerated cork matrix impregnated with a polymeric material and at least one second layer made of said polymeric material. The invention also relates to the process of manufacturing the cork fabric comprising the steps of: a) production of a thin layer of a natural or agglomerated cork matrix; b) impregnation by fusion of at least one layer of polymeric material into the matrix of the cork layer; and c) stabilization and cooling down. The cork fabric so formed has unique mechanical features enabling its use in the manufacturing of, e. g., inner and outer linings, covers, packages, panels, tiles, wallpaper, furniture, footwear, bags, toys, notebooks, placards and professional cards.

Description

"CORK FABRIC AND PROCESS FOR THE PRODUCTION THEREOF" Field of the invention

The present invention relates to a malleable and mouldable cork fabric based on a natural or agglomerated cork matrix, which matrix is impregnated with a polymeric material. The invention also relates to the process of manufacturing the cork fabric and to objects which can be manufactured from the cork fabric.

Background of the Invention

Cork, that man collects with such great care, has unique unmatched qualities that up to present the human ingenuity has been unable to emulate, let alone to surpass; in fact, cork is a material which: is extremely light;

is impermeable to liquids and to gases;

is elastic and also compressible;

is an excellent thermal and sound insulating material;

is a slow burning material;

is highly resistant to friction.

Furthermore, cork is a totally natural material, which can be recycled and is biodegradable. These are three indispensable characteristics in a society like the one we live in.

In the last few years, architects, designers and decorators have shown a renewed interest in natural materials, among which cork, which, due to the many different existing decorative and coating products, distinctive by several textures, shades and colours, which allows the creation of distinct ambiances for the most different uses, always taking advantage of its inherent comfort. The use of cork in decoration has been increasing its popularity, both for professional applications and for "do-it-yourself" uses.

It is foreseen that the use of cork products, employed together with other materials, for structural purposes, as well as in uses characterized by an extremely high added value, as in the case of innovating applications in the building sector and in other specific sectors, will continue to increase.

Accordingly, the use of cork in association with other materials is common in the cork industry, enhancing the overall mechanical features of the resulting material and therefore extending the use of cork to most of usual applications. For this purpose, in order to impart better mechanical strength to cork based products, is usual to adhere the cork material to other support/reinforcement materials, e. g. , wood, stone, plastics and metallic materials, or also to produce composites of cork and fibres.

However a problem persists when dealing with thin layers of cork material. In fact, for a natural or agglomerated cork sheet having a small thickness, brittleness and small tensile strength are observed, which makes it difficult to use it in articles requiring the combination of small thickness, malleability and high tensile strength.

In these cases the adhesion of the thin cork layer to a reinforcement substrate or the use of composites of cork and fibres have proved not being suitable since the resulting material is not malleable enough to meet some applications. For better understanding and contextualization of the present invention, some examples of related prior art are given herein below.

US 2011099853 A l , entitled "Cork Outer Soled Shoes and Method for Fabrication" , relates to a process for fabricating shoes having an outer cork sole insert. This process includes processing raw cork into sheets of predetermined thickness, adhering a thin fabric sheet to one side of the intermediate cork sheets, cutting out cork/fabric sole inserts and placing them into an injection mold, and cycling the plastic injection mold. This document relates to the production of cork sheets but does not relates to the use of a polymeric component nor printed techniques in cork.

GB 2108426 A, entitled "Method of Making Decorative Laminated Products Such as Tiles, Panels or Webs", discloses a laminated decorative floor tile which comprises a base layer of granulated cellulosic material, e.g. cork, in a matrix of fusible plastics, and placing on the base layer a thin decorative layer of cellulosic material, e.g. cork with natural holes and recesses. Then, a film of fusible plastic is applied to the decorative layer and, using methods of hot press and immediately cooled, the film fills the holes and recesses of the decorative layer. This document neither discloses impregnation of cork with a thermoplastic material nor printing techniques of decorative patterns in cork.

KR 20020036066 A, entitled "Cork Non-Woven Fabric Rush Mat", discloses a rush mat which comprises a unit component made of a number of materials and a cork non- woven fabric attached with the unit component. The cork fabric is formed by heating and plasticizing a cork material with heat and pressure to form a cork combination; cutting this combination into a cork sheet; and adhering the cork sheet to a non-woven sheet. The cork fabric is laminated with the component and lined by a trim component. However, this disclosure does not relate to a cork fabric in the sense as the present invention.

EP 1990186 A2, entitled "Digitally Printed Cork Base Plates", relates to the production of digitally printed cork floor tiles. The cork substrate is subject to temperatures above 150 °C, adhered and pressed to a damping layer and a high density fibreboard carrier plate. Then, an acrylic-based dispersion dye is applied as barrier, an ultraviolet-hardening dye is applied by digital printing method followed by the application of a sealing layer. This invention does not relate to the use of cork in combination with a polymer. ES 2084541 Bl , entitled "Novel Decorative, Insulating Panel and Process for

Producing It", discloses a panel formed by a base substrate made from agglomerated cork which has, applied to its visible face, a pigmented base layer to which a finishing layer is applied by stamping. This latter layer having the chosen finishing appearance is then covered by one or more layers of varnish with the desired shine and hardness. The process comprises the initial application of the base pigment by means of calendering, drying by means of ultraviolet rays, sanding the face equipped with the base layer and then a stage of stamping a design on said face by means of a roller or transfer. Finally, the stamping is covered with varnish layer(s). Although this invention relates to stamping of cork agglomerate, there is no reference to the presence of polymer compounds in combination with cork agglomerate of the substrate. US 2010319282 Al , entitled "Floor Panel Containing a Polymer and Cork" , relates to a vinyl floor panel prepared from a blend of a polymer and cork granules. The floor panel includes top and bottom surfaces with a first layer between both surfaces. The first layer is prepared from a blend of a polymer, polyvinyl chloride, and cork granules, where the cork granules are evenly distributed with the polyvinyl chloride throughout the length, width, and thickness. A printed pattern is located on the top surface of this layer. This invention does not relate to impregnation by fusion of a polymer into the cork matrix.

Therefore a need exists of a fabric like cork material that combines the unique characteristics of cork with the malleability and tensile strength of some woven fabrics, and which at the same time allows for an easy printing of decorative patterns.

Summary of the Invention The present invention relates to a malleable and mouldable cork fabric based on a natural or agglomerated cork matrix, the cork fabric comprising a first layer made of the natural or agglomerated cork matrix impregnated with a polymeric material and at least one second layer made of said polymeric material. In one aspect of the invention, the thickness of the first layer of natural or agglomerated cork matrix impregnated with the polymeric material is in the range of 0.2-15 mm. Preferably, the thickness of the first layer of natural or agglomerated cork matrix impregnated with the polymeric material is in the range of 0.3-1.5 mm, more preferably said thickness of the first layer is 0.6 mm.

In a further aspect, said polymeric material comprises a polymer selected from the group comprising polyurethane, polyvinyl chloride, poly(ethylene terephthalate), polyester and combinations thereof. Preferably, the polymeric material of the cork fabric comprises polyurethane.

In another aspect, the cork fabric of the invention further comprises at least one support layer adhered therein. The support layer of the invention is selected from the group comprising woven, non-woven and knitting fabrics, plastic, metallic and wood materials, cork, paper, carton, leather and stone.

In still another aspect, the cork fabric further comprises a finishing layer, which finishing layer can be selected from the group comprising varnishes, resins and paints.

The cork fabric of the invention can be used, for example, in inner and outer linings, covers, packages, seats, panels, tiles, furniture, wallpaper, footwear, bags, purses, belts, toys, notebooks, placards and professional cards.

The invention also relates to a ball comprising an inner inflatable bladder enclosed in an outer cover, which outer cover is made of the cork fabric of the invention. The ball can be selected, for example, from the group comprising football ball, volleyball ball, basketball ball, handball ball, and rugby ball.

The present invention further relates to a process for producing a cork fabric of the invention. The process comprises: a. production of a natural or agglomerated cork matrix in the form of a thin layer having a thickness of 0.2 to 15 mm, b. impregnation by fusion of at least one layer of polymeric material into the matrix of the cork layer obtained in step a), at a temperature ranging from 80 °C to 220 °C and a pressure ranging from 3 bar to 10 bar, and c. stabilization and cooling down.

In one aspect of the process of the invention, the thickness of the cork layer of step a) is in the range of 0.3-1 .5 mm, more preferably is 0.6 mm.

In other aspect, the step b) is carried out by a press or by a calander.

In another aspect, the process comprises a further step of printing the cork layer and/or the polymeric layer before step b).

In still another aspect, the process of the invention comprises a further step of printing the cork fabric after step c).

In a further aspect, the step of printing is carried out by image transfer, sublimation, screen printing, digitalisation, ink jet, laser or painting.

In other aspect, the image transfer printing is carried out by a calander, at a temperature in the range of 60 °C to 450 °C, at a pressure in the range of 3 to 16 bar, and at a speed in the range of 2 to 25 m/min.

In still other aspect, the image transfer printing is carried out by a press with a contact time in the range of 5 to 45 seconds. In still another aspect of the invention, the process comprises a further step of adhesion of at least one support layer to the cork layer before step b).

In other aspect, the process comprises a further step of adhesion of at least one support layer to the cork fabric after step c).

Said support layer can be selected from the group comprising woven fabrics, plastic, metallic and wood materials, cork, paper, stone and combinations thereof. In another aspect, the process of the invention further comprises a finishing step for applying at least one finishing layer onto the cork fabric, wherein the finishing layer is selected from the group comprising varnishes, resins, paints and combinations thereof.

Detailed Description of the Invention

The present description discloses a malleable and mouldable cork fabric based on a natural or agglomerated cork matrix, the cork fabric comprising a first layer made of the natural or agglomerated cork matrix impregnated with a polymeric material and at least one second layer made of said polymeric material.

In the context of the present specification the term "and/or" means that both conditions are met or just one of them is met. For example, the expression "the first cork layer and/or the second polymeric layer" means "the first cork layer and the second polymeric layer or the first cork layer or the second polymeric layer" .

Unless otherwise explicitly mentioned, the ranges shown in the present specification are intended to provide a simply and technically accepted way for denoting each single value within the range. By way of example, the term " 1 to 2" or "between 1 and 2" means any value within this range, for instance, 1.0; 1.1 ; 1.2; 1.3; 1.4; 1.5; 1.6; 1.7; 1.8; 1.9; 2.0. Every value mentioned in the present specification must be construed as an approximate value, for example the reference to "2.0" means "about 2.0" As raw material, the cork performance lies in its cell structure. The interior of the cork is made up of a honeycomb of tiny cells of suberin, a complex acid, and filled with a mixture of gas almost identical to air. On average, each cubic centimeter of cork contains 40 million cells, while one cork stopper contains around 800 million cells.

Chemical composition of cork:

• suberin (45 %) - main component of the cell walls, responsible for the elasticity of the cork;

• lignin (27%) - insulating compound;

• polysaccharides (12%) - components of the cell walls which define the texture of the cork;

• tannins (6%) - polyphenols compounds responsible for the colour;

· seroids (5%) - hydrophobic compounds that assure the impermeability of the cork.

The term "cork matrix" relates to the honeycomb type structure (also named open-cell structure) of the cork material as better explained above.

Surprisingly, it has been found that a thin and brittle sheet of cork could be rendered malleable and mouldable by filling its open cell structure with a polymeric material, which is also referred in the present description as "cork matrix impregnated with a polymeric material" .

In addition to the excellent malleability and moldability characteristics almost similar to a woven fabric, the fabric cork of the invention also shows a very significant improvement in tensile strength as compared with starting cork sheet. These effects were completely unexpected, since the person skilled in the art would eventually expect the new cork material to show some enhancement of "plasticity" and "impermeability" when compared to natural or agglomerated cork, but not the high level of malleability and moldability achieved with the present cork fabric, only compared to that of a traditional textile fabric.

Additionally, the cork fabric of the present invention enables to print high quality decorative patterns therein.

This new fabric like cork material allows for the manufacturing of a broad range of products for industrial fields like building, clothing, footwear, decoration, furniture, luggage, bags, purses, belts and the like, more particularly, e. g. , for the manufacturing of inner and outer linings, covers, seats, packages, panels, tiles, wallpaper, toys, notebooks, placards and professional cards.

As mentioned earlier, the cork fabric of the invention is based on a natural or agglomerated cork matrix, which is impregnated with a polymeric material and comprises at least one second layer made of said polymeric material.

Said first layer of natural or agglomerated cork matrix impregnated with the polymeric material has a thickness in the range of 0.2-15 mm, preferably of 0.3-1.5 mm and more preferably is 0.6 mm.

The polymeric material comprises polyurethane or is selected from the group comprising polyvinyl chloride, poly(ethylene terephthalate), polyester, and the like and combinations thereof. In one embodiment, the cork fabric of the invention further comprises at least one support layer adhered therein. The support layer can be selected from the group comprising woven, non-woven and knitting fabrics, plastic, metallic and wood materials, cork, paper, carton, leather and stone. The cork fabric may further comprise a finishing layer selected from the group comprising varnishes, resins and paints. Decorative patterns may be applied to the cork fabric or to any of the fabric layers.

By way of example, the cork fabric may be embodied, e. g. , in a ball selected from the group comprising foot ball, volley ball, basket ball, hand ball, and rugby ball. Herein below an example of a football ball is given.

The present invention also relates to the process for producing a cork fabric. The process comprises the following steps of: a. production of a natural or agglomerated cork matrix in the form of a thin layer having a thickness of 0.2 to 15 mm, impregnation by fusion of at least one second layer of polymeric material into the matrix of the cork layer obtained in step a), at a temperature ranging from 80 °C to 220 °C and a pressure ranging from 3 bar to 10 bar, and c. stabilization and cooling down. Regarding step a), the agglutination of cork granules, with specific granulometry and density, by the joint action of pressure, temperature and an agglutinating agent results in a agglomerated cork roll that, after stabilization, is laminated (cut) to the desired thickness by means of a continuous laminating (cutting) procedure, resulting in a continuous sheet that is constantly rolled.

A non-continuous shape of natural or agglomerated cork may be also obtained by any known procedure.

Preferably, the thickness of the cork layer of step a) is in the range of 0.3-1.5 mm, more preferably is 0.6 mm. The impregnation by fusion of step b) of the process of the invention may be preferably carried out at a temperature ranging from 140 °C to 200 °C, more preferably from 160 °C to 190 °C, and most preferably from 165 °C to 180 °C. The step b) of the process of the invention may be preferably carried out at a pressure ranging from 3.5 bar to 8 bar, more preferably from 4 bar to 6 bar.

In an embodiment the step b) of the process of the invention is carried out by a press or a calander.

In another embodiment, a further step of printing the cork layer and/or the polymeric layer before step b) is carried out.

In a further embodiment, the step of printing the cork fabric is carried out after step c) of the process.

The above printing step can be carried out, e. g. , by image transfer, sublimation, screen printing, digitalisation, ink jet, laser or painting. Particularly, said image transfer printing may be performed using a calander at a temperature comprised between 60 and 450 °C, a pressure comprised between 3 and 16 bar and a velocity comprised between 2 and 25 m/min or, preferably, at a temperature comprised between 80 and 300 °C, or, even more preferably, at a temperature comprised between 130 and 200 °C.

Optionally, the image transfer printing may be carried out using a press with a contact time between 5 and 45 seconds, preferably, in the range of 10 to 30 seconds.

In a further embodiment, the process of the invention comprises a further step of adhesion of at least one support layer to the cork layer before step b). In another embodiment, the step of adhesion of least one support layer to the cork fabric is carried out after step c) of the process of the present invention.

Said support layer is selected from the group comprising woven, non- woven and knitting fabrics, plastic, metallic and wood materials, cork, paper, carton boards, leather, stone and the like and combinations thereof.

In a still further embodiment, the process of the invention further comprises a finishing step for applying at least one finishing layer onto the cork fabric, wherein the finishing layer is selected from the group comprising varnishes, resins, paints and combinations thereof.

By way of an example, a process for obtaining a cork fabric made of granulated cork and polymeric material comprises the following steps: mixing of the cork particles with a granulometry in the range of 0.2 and 1.5 mm, by agglutination, with at least a suitable agglutinating agent, the agglutination agent may be polyurethane, carbolic glue, melaminic resin, urea formaldehyde, melamine or combinations thereof; stabilization, of the previously obtained cork rolls; lamination (cutting) of the precedent cork cylinder into a cork sheet having a thickness of 0.6 mm, for instance in laminating machines, guillotines, saws, trimmer saws, roll formers or sanding machines; printing of the cork sheet and/or the polymeric layer.

Impregnation by fusion of the polymeric layer into the cork matrix. Also by way of example, if a white cork fabric is to be obtained, a white polymeric layer must be fused into the cork matrix, followed by a second transparent polymeric layer (optionally printed) that is fused to the white polymeric layer. Following five embodiments of the invention are given for illustrative purposes only, which are not intended to limit the scope of the invention.

Example 1 The process for the production of a printed cork fabric comprising a non woven support layer included the following steps:

- A cork agglomerate roll with 1.00 m width and 0.6 mm thickness was obtained by agglutinating cork granules with a granulometry in the range of 0.5 to 1 mm, and a density of 60 kg/m3, with polyurethane (the agglutinating agent) followed by lamination to the desired thickness;

-The the cork agglomerate thus obtained was printed by sublimation in a flat slab press at a temperature of 190 °C, a pressure of 4 bar, and a contact time of 17 s;

- The printing was stabilized for 24 h at room temperature, before removal of the detachable component

- A non-woven substrate was glued to the non printed side of the cork agglomerate, by means of a continuous hot-melting glue system, using a calander, at a temperature of approximately 130 °C;

- A polyurethane layer was impregnated by fusion into the matrix of the cork agglomerate reinforced with the non-woven support obtained in the preceding step. The equipment used was a double transfer printing + bonding press (3100 x

1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s. - The detachable silicone paper was removed after stabilization for a few minutes,

Example 2

The process for the production of a printed cork fabric, without support layer, included the following steps:

- A cork agglomerate roll with 1.00 m width and 0.6 mm thickness was obtained, by agglutinating cork granules with a granulometry in the range of 0.5 to 1 mm, and a density of 60 kg/m3, with polyurethane (the agglutinating agent) followed by lamination to the desired thickness;

- A white polyurethane layer was impregnated by fusion into the matrix of the cork agglomerate obtained in the preceding step, in order to provide a white background. The equipment used was a double transfer printing + bonding press (3100 x 1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

- stabilization for a few minutes.

- A drawing was digitally printed (with ECO-solvent inks) on top of a polyurethane layer.

- the polyurethane layer was glued to the white side of the cork fabric by a melting process, using a double transfer printing + bonding press (3100 x 1600 mm), operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

-The detachable silicone paper was removed after stabilization for a few minutes. Example 3

The process for the production of a printed cork fabric, with a woven support layer, included the following steps:

- A cork agglomerate layer was printed by continuous transfer of the drawing from the transfer paper to the layer of cork agglomerate carried out in a calender, at a pressure in the range of 4 to 4.5 bar, at a temperature of 130° C, and at an approximate velocity of 5 m/min.

- After stabilization of the printing for approximately 24 hours at room temperature, the detachable component was removed and the printed layer of cork agglomerate was rolled up.

- A self adhesive was applied (roll width = 1 m; glue grammage = 50 g/cm2) to the non-printed side of the cork agglomerate, followed by gluing the woven (polyester/cotton) support to the cork sheet. - A polyurethane layer was impregnated by fusion into the printed side of the cork agglomerate reinforced with the woven support obtained in the preceding step. The equipment used was a double transfer printing + bonding press (3100 x 1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

-The detachable silicone paper was removed after stabilization for a few minutes.

Example 4

The process for the manufacturing of a CD cover made of printed cork fabric includes the following steps: -Obtaining a cork agglomerate roll with 1 .00 m width and 0.6 mm thickness, by agglutinating cork granules with a granulometry in the range of 0.5 to 1 mm, and a density of 60 kg/m3, with polyurethane (the agglutinating agent) followed by lamination to the desired thickness;

Impregnation by fusion of a polyurethane/polyvinyl chloride layer into the cork agglomerated matrix. The equipment used was a double transfer printing + bonding press (3100 x 1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

-Stabilization for a few minutes, followed by the removal of the detachable silicone paper.

-Digital printing (with ECO-solvent inks) of the drawing/text on top of another polyurethane/polyvinyl chloride layer.

-Impregnation by fusion of the printed layer obtained in the preceding step into the non-coated side of the cork fabric; the equipment used was a double transfer printing + bonding press (3100 x 1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

-Cutting of the rectangles with the appropriate dimensions.

-Manufacturing of the CD cover with two lateral seams with straight stitches. Example 5

The process for the manufacturing of a foot ball made of cork fabric included the following steps:

-A cork agglomerate roll with 1.00 m width and 0.6 mm thickness, was obtained by agglutinating cork granules with a granulometry in the range of 0.5 to 1 mm, and a density of 60 kg/m3, with polyurethane (the agglutinating agent) followed by lamination to the desired thickness;

-A support layer made of a cotton fabric and a polyurethane coagulated polyester net was glued to the cork agglomerate, by means of a continuous hot-melting glue system, using a calander, at a temperature of approximately 130 °C; - A polyurethane layer was impregnated by fusion of into the matrix of the cork agglomerate reinforced with the support layer obtained in the preceding step. The equipment used was a double transfer printing + bonding press (3100 x 1600 mm) operating under the following conditions: temperature = 170°C; pressure = 4 bar; pressing time = 20 s.

-The detachable silicone paper was removed after stabilization for a few minutes..

-Hexagons and pentagons were cut with the appropriate dimensions. - All but the last three geometric parts obtained in the preceding step were manually stitched in order to obtain an almost spherical form. Glue the bladder inflation valve to one of the geometric parts already in place and complete the stitching of the remaining parts to close the ball. -The ball was inflated to the adequate pressure, in order to obtain a spherical shape.

Claims

1. A malleable and mouldable cork fabric based on a natural or agglomerated cork matrix, the cork fabric comprising a first layer made of the natural or agglomerated cork matrix impregnated with a polymeric material and at least one second layer made of said polymeric material.

2. The cork fabric according to claim 1, wherein the thickness of the first layer of natural or agglomerated cork matrix impregnated with the polymeric material is in the range of 0.2-15 mm.

3. The cork fabric according to claim 1 , wherein the thickness of the first layer of natural or agglomerated cork matrix impregnated with the polymeric material is in the range of 0.3-1.5 mm.

4. The cork fabric according to claim 1 , wherein the thickness of the first layer of natural or agglomerated cork matrix impregnated with the polymeric material is 0.6 mm.

5. The cork fabric according to claim 1 , wherein the polymeric material comprises a polymer selected from the group comprising polyurethane, polyvinyl chloride, poly (ethylene terephthalate), polyester and combinations thereof.

6. The cork fabric according to claim 1 , wherein the polymeric material comprises polyurethane.

7. The cork fabric according to claim 1 further comprising at least one support layer adhered therein.

8. The cork fabric according to the preceding claim wherein the said support layer is selected from the group comprising woven, non-woven and knitting fabrics, plastic, metallic and wood materials, cork, paper, carton, leather and stone.

9. The cork fabric according to any of the preceding claims, further comprising a finishing layer.

10. The cork fabric according to the preceding claim, wherein said finishing layer is selected from the group comprising varnishes, resins and paints.

11. Cork fabric according to any of the preceding claims for use in inner and outer linings, covers, packages, panels, tiles, wallpaper, footwear, bags, purses, belts toys, notebooks, placards and professional cards.

12. A ball, comprising an inner inflatable bladder enclosed in a outer cover characterized in that the outer cover is made of cork fabric, according to any of claims 1 to 10.

13. The ball, according to the preceding claim, selected from the group comprising football ball, volleyball ball, basketball ball, handball ball, and rugby ball.

14. A process for producing a cork fabric, comprising: a. production of a natural or agglomerated cork matrix in the form of a thin layer having a thickness of 0.2 to 15 mm, characterized in that it further comprises the steps of: b. impregnation by fusion of at least one layer of polymeric material into the matrix of the cork layer obtained in step a), at a temperature ranging from 80 °C to 220 °C and a pressure ranging from 3 bar to 10 bar, and c. stabilization and cooling down.

15. Process according to claim 14, wherein the thickness of the cork layer of step a) is in the range of 0.3-1.5 mm.

16. Process according to claim 14, wherein the thickness of the cork layer of step a) is 0.6 mm.

17. Process according to claim 14, wherein the step b) is carried out by a press or a calander.

18. Process according to claim 14, comprising a further step of printing the cork layer and/or the polymeric layer before step b).

19. Process according to claim 14, comprising a further step of printing the cork fabric after step c).

20. Process according to claim 18 or 19, wherein said step of printing is carried out by image transfer, sublimation, screen printing, digitalisation, ink jet, laser or painting.

21. Process according to claim 20, wherein the image transfer printing is carried out by a calander, at a temperature in the range of 60 °C to 450 °C, at a pressure in the range of 3 to 16 bar, and at a speed in the range of 2 to 25 m/min.

22. Process according to claim 20, wherein the image transfer printing is carried out by a press with a contact time in the range of 5 to 45 seconds.

23. Process according to claim 14, comprising a further step of adhesion of at least one support layer to the cork layer before step b).

24. Process according to claim 14, comprising a further step of adhesion of at least one support layer to the cork fabric after step c).

25. Process according to claims 23 or 24, wherein the support layer is selected from the group comprising woven fabrics, plastic, metallic and wood materials, cork, paper and stone.

26. Process according to any of claims 14 to 25, further comprises a finishing step for applying at least one finishing layer onto the cork fabric, wherein the finishing layer is selected from the group comprising varnishes, resins and paints.