* * * *

The present invention relates to a coupling method of a cellulose material with a support material made of leather or natural and/or synthetic fabric or non- woven material.

Granted European Patent EP-2523758 describes an application method of a finishing paper material on a support material made of leather and fabric, comprising:

- a first buttering of glue on a surface of the support material;

- positioning the finishing material on said support material;

- ironing,

- perching,

- second buttering of glue,

- step of dressing.

Said step of dressing may include drawing up a protective film on said finishing material, ironing and a step of removing said protective film.

Alternatively, said step of dressing may comprise a step of drawing up a polyurethane film and a step of ironing.

Disadvantageously, the method described in EP-2523758 includes the use of adhesive and interlacing agent and a sequence of operative steps which imply a double buttering, which limits the processing speed to obtain the finished product.

Furthermore, use of the adhesive-interlacing agent system is potentially polluting for the environment, sometimes exposes to health risks and in all cases is not simple to apply.

It is the object of the present invention to provide a coupling method of a cellulose material with a support material made of leather or natural and/or synthetic fabric or non-woven material without the use of glues, i.e. heat activated adhesives and/or pressure sensitive adhesives. It is a further object of the present invention to make a simple coupling method, which uses cost-effective compounds and which allows to obtain a semifinished product with a surface having chemical-physical properties which allow the subsequent traditional operations, such as the dressing of leather and/or the finishing of synthetic or natural fabrics or of non-woven materials or the adhesion of foils also of inorganic nature.

It is a yet further object of the present invention to make a coupling method which allows to obtain an environment-friendly semifinished product which ensures a more natural appearance to the semifinished product.

In accordance with the invention, said objects are reached by a coupling method of a cellulose material with a support material made of leather or natural and/or synthetic fabric or non-woven material, characterized in that the cellulose material has a percentage of cellulose higher than 95% and a thickness lower than 50 microns, and in that it comprises the following steps in sequence:

- applying on the support material (3), by spraying or buttering, from 50 to 100 grams per square meter of initial support material (3) of a water-based thermoplastic polymer (4) of acrylic and/or polyurethane and/or combined acrylic-polyurethane nature;

- coupling the cellulose material (2) with the support material (3), at an applied pressure comprised between 50 and 150 bar and a temperature comprised between 80 and 150°C, to obtain an intermediate semifinished product (5);

- impregnating said intermediate semifinished product (5) with another water-based thermoplastic polymer (4) of acrylic and/or polyurethane and/or combined acrylic-polyurethane nature.

These and other properties of the present invention will be more apparent from the following detailed description of an example of practical embodiment.

A coupling method of a cellulose material 2, i.e. consisting of a variable percentage of cellulose also of marine origin, with a support material 3 made of leather or natural and/or synthetic fabric or non- woven material, includes the use of a water-based thermoplastic polymer 4 of acrylic and/or polyurethane and/or combined acrylic-polyurethane nature.

Cellulose material 2 means paper or other material with a high percentage of cellulose, i.e. exclusively with a percentage of cellulose higher than 95% for the reasons which will be explained below.

Said method comprises the following steps in sequence:

- applying on the support material 3, by spraying or buttering, a water- based thermoplastic polymer 4 from 50 to 100 grams of thermoplastic polymer 4 per square meter of support material 3;

- coupling the cellulose material 2 with the support material 3, at controlled temperature and pressure to obtain an intermediate semifinished product 5; the applied pressure is preferably comprised between 50 and 150 bar and the temperature is preferably comprised between 80 and 150°C; the thickness of the cellulose material 2 is lower than 50 microns;

- impregnating said intermediate semifinished product 5 with another water-based thermoplastic polymer 4, preferably from 50 to 200 grams of thermoplastic polymer 4 per square meter of intermediate semifinished product 5; said impregnation makes the surface of the semifinished product particularly suitable for the subsequent operations of dressing, finishing and adhesion of various materials.

A cellulose material 2 with a high percentage of cellulose as indicated above must be used because only in this manner does the cellulose material 2 display fibers which may adapt in optimal manner and facilitate a contact, and a consequent close bond, with the support material 3.

Furthermore, the high percentage of cellulose confers very important hydrophilic properties to the cellulose material 2 for the interaction with the thermoplastic polymer 4.

The thickness of the cellulose material 2 is also critical, because percolation after coupling must be ensured. Indeed, delaminating may occur, in addition to an enhancing of the thermal insulating effect, which could obstruct the close coupling of the materials used, at values higher than 150 microns.

The thermoplastic polymer 4 promotes the flow of the cellulose fibers and allows to achieve the "binding" effect without using glues.

It is worth noting that the dosages of thermoplastic polymer 4 indicated above depend on the absorption capacity of the material. During the step of impregnating, the upper dosing limit (200 gram/square meter) is double that of the first step of applying (100 grams/square meter) because the impregnation occurs in multiple steps of spraying or buttering.

Vice versa an excessive amount of polymer 4 during the first step does not guarantee greater coupling efficacy with the support material 3 underneath, thus being unnecessary and not cost-effective.

Breakages occur in the cellulose material continuity which preclude the use of the semifinished product 5 during the subsequent processing steps if the percentage of cellulose is not high.

Consequently, the method described above allows to obtain a smooth semifinished product without breakages which appears to be formed by a single composite layer deriving from the copenetration of the various layers of the polymer 4.

The method described above also has the following significant advantages:

- the semifinished product may be used smooth or later printed;

- leather with scars, pitting and other evident faults in general may be used, by enhancing them and making them usable with a significant reduction of waste material;

- elimination of the step of shimming; simplification and reduction of the traditional processing steps, maintaining or increasing the quality performance; - drastic reduction of the problems of peeling and increase of tumbling/milling/perching resistance;

- maintaining and/or achieving a level of softness of the leather which cannot be obtained with other known coupling and/or buttering methods;

- the finishing layers are reduced with consequent decrease of the amount of chemical products used (environmental-friendliness aspect) and a more natural appearance of the finished product is ensured; by way of example, the use of primer and of insulation is eliminated from the usual leather dressing process consisting of "pigmented primer - insulation by means of polyethylene in aqueous dispersion or nitroemulsion - printing - miscellaneous mechanical operations - dyeing - fixative" by proceeding with the "application of synthetic polymer- coupling of cellulose material 2 - printing - miscellaneous mechanical operations - dyeing - fixative";

- usable in the leather goods, footwear, furniture, clothing, automotive sectors;

- usable on "full grain" leather, and on "split leather" and/or "skivers";

- usable for making "false grain" items from "skivers" and "split leather" also on "flesh side";

- shorter processing times.

The method described above allows to obtain a semifinished product with physical strength which cannot be reached with other techniques.

Said strength features are summarized in the table shown below, in which various strength tests performed on a semifinished product obtained with the innovative technique described herein and on a semifinished product obtained with the prior art are compared. Tests and reference standards Innovation Prior art

Color fastness to rubbing cycles Wet >400 cycles Wet >200 cycles ISO 1 1640:2012 (IULTCS/IUF

450) Dry >800 cycles Dry >400 cycles

Test for adhesion of finish > 3 N/cm < 1 N/cm

ISO 11644:2009 (IULTCS/IUF

470)

Determination of flex resistance by > 30000 cycles < 15000 cycles flexometer method

ISO 5402:2002 (IULTCS/IUP 20)