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Title:
PROCEDURE FOR OBTAINING WATER/OIL REPELLENT FABRICS AND/OR LEATHERS AND RELATED PRODUCT THUS OBTAINED
Document Type and Number:
WIPO Patent Application WO/2022/107178
Kind Code:
A1
Abstract:
Described is a process for the production of water/oil repellent synthetic microfibre fabrics and/or leathers, which involves a step of applying wetting or hydrophilizing agents or compounds on at least a portion of one side of the fabric and/or leather. The invention also relates to a synthetic microfibre fabric and/or a leather made starting from the above-mentioned process. The fabrics and leathers can also be shaped on the lower side by applying a three-dimensional structure on the reverse side impressed in a permanent manner, which favours the presence of air channels on the internal side, in order to increase breathability and thermal comfort, thanks to the reduction of contact points. This application may take place by mechanical or pneumatic compression, thermo-forming, high-frequency or similar techniques designed for making the lower or internal side, facing the user's epidermis, three- dimensional.

Inventors:
NEGRO IVAN (IT)
NEGRO MIRCO (IT)
FRIZZO ANTONIO (IT)
Application Number:
PCT/IT2021/050370
Publication Date:
May 27, 2022
Filing Date:
November 17, 2021
Export Citation:
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Assignee:
MITH SRL (IT)
International Classes:
D06M15/643; C14C9/00; D06N3/00
Domestic Patent References:
WO2001010922A12001-02-15
Foreign References:
US20080039558A12008-02-14
US20140366280A12014-12-18
US5316860A1994-05-31
Attorney, Agent or Firm:
BURCHIELLI, Riccardo et al. (IT)
Download PDF:
Claims:
7

CLAIMS

1 . Process for obtaining water/oil repellent fabrics and/or leathers, characterized in that said process includes a step of applying wetting or hydrophilizing agents or compounds on at least one portion of one side of a fabric or leather.

2. Process as claimed in claim 1 , characterized in that said step of applying said wetting or hydrophilizing agents or compounds is carried out on at least one portion of a lower or internal side facing the user's epidermis of said fabric or leather, a waterproofing step being also applied on at least one portion of the side opposite to said lower or internal side.

3. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds are applied by means of vertical, rotary or cylinder printing techniques, by deposition through screen and/or pad printing systems or similar techniques.

4. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds comprise polysiloxane acids, esters of carboxylic acids, silicone nano-emulsions, silicone micro-emulsions, silicone macro-emulsions, polyglycol ethers or ethers polyglycolics.

5. Process as claimed in at least one of the preceding claims, characterized in that said application of wetting or hydrophilizing agents or compounds is carried out on synthetic microfibre fabrics, such as “Suede” microfibre fabrics and/or microfibre fabrics finished with polyurethane and mixed films.

6. Process as claimed in at least one of the preceding claims, characterized in that a three-dimensional structure is permanently impressed on said internal or lower side, thus obtaining air channels for providing high breathability and considerable thermal comfort, thanks to the reduction of the contact points, said three- dimensional structure being impressed by mechanical means, pneumatic means, thermo-forming means, high frequency or similar techniques.

7. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds have variable weight percentages on the basis of the weight and thickness of the leather, in particular between 3% and 30% by weight and more particularly 15% by weight.

8. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds are treated with dilutions in aqueous solution with ratios 1 :1 , 1 :2, 1 :3 and relative percentages on the basis of the dry weight of said fabric or leather, at temperatures between 35 °C and 70 °C 8 and with PH values between 3.5 and 7.5, said agents or compounds being applied by spraying or by transferring from a support or cylinder.

9. Process as claimed in at least one of the preceding claims, characterized in that said step of applying wetting or hydrophilizing agents or compounds is carried out during a leather tanning process and, in particular, during the retanning, dyeing and fatliquoring or final finishing steps and characterized in that, after said phase of applying wetting or hydrophilizing agents or compounds, said fabric or leather is subjected to a mechanical processing, such as ironing, pressing and/or conditioning, at temperatures between 70 °C and 120°C. 10. Microfiber fabric or leather made by means of a process as claimed in claim 1 , wherein said fabric or leather is applied to different sectors, such as, in particular, automotive, clothing, footwear, leather goods, furniture.

9

AMENDED CLAIMS received by the International Bureau on 31 March 2022 (31.03.2022)

1 . Process for obtaining water/oil repellent fabrics and/or leathers, characterized in that said process includes a step of applying wetting or hydrophilizing agents or compounds on at least one portion of a lower or internal side facing the user’s epidermis of a fabric or leather, a waterproofing step being also applied on at least one portion of the side opposite to said lower or internal side.

2. Process as claimed in claim 1 , characterized in that said wetting or hydrophilizing agents or compounds are applied by means of vertical, rotary or cylinder printing techniques, by deposition through screen and/or pad printing systems.

3. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds comprise polysiloxane acids, esters of carboxylic acids, silicone nano-emulsions, silicone micro-emulsions, silicone macro-emulsions, polyglycol ethers.

4. Process as claimed in at least one of the preceding claims, characterized in that said application of wetting or hydrophilizing agents or compounds is carried out on synthetic microfibre fabrics, such as “Suede” microfibre fabrics and/or microfibre fabrics finished with polyurethane and mixed films.

5. Process as claimed in at least one of the preceding claims, characterized in that a three-dimensional structure is permanently impressed on said internal or lower side, thus obtaining air channels for providing high breathability and considerable thermal comfort, thanks to the reduction of the contact points, said three- dimensional structure being impressed by mechanical means, pneumatic means, thermo-forming means, high frequency.

6. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds have variable weight percentages on the basis of the weight and thickness of the leather, in particular between 3% and 30% by weight and more particularly 15% by weight.

7. Process as claimed in at least one of the preceding claims, characterized in that said wetting or hydrophilizing agents or compounds are treated with dilutions in aqueous solution with ratios 1 :1 , 1 :2, 1 :3 and relative percentages on the basis of the dry weight of said fabric or leather, at temperatures between 35 °C and 70 °C and with PH values between 3.5 and 7.5, said agents or compounds being applied by spraying or by transferring from a support or cylinder.

8. Process as claimed in at least one of the preceding claims, characterized in that said step of applying wetting or hydrophilizing agents or compounds is carried out during a leather tanning process and, in particular, during the retanning, dyeing

AMENDED SHEET (ARTICLE 19) and fatliquoring or final finishing steps and characterized in that, after said phase of applying wetting or hydrophilizing agents or compounds, said fabric or leather is subjected to a mechanical processing, such as ironing, pressing and/or conditioning, at temperatures between 70 °C and 120°C. 9. Microfiber fabric or leather made by means of a process as claimed in claim 1 , wherein said fabric or leather is applied to different sectors, such as, in particular, automotive, clothing, footwear, leather goods, furniture.

AMENDED SHEET (ARTICLE 19)

Description:
PROCEDURE FOR OBTAINING WATER/OIL REPELLENT FABRICS AND/OR LEATHERS AND RELATED PRODUCT THUS OBTAINED

This invention relates to a process for obtaining water/oil repellent fabrics and/or leathers, as well as the related product obtained.

The products are functionalized with hydrophilizing treatment on one of the sides, preferably on the lower or internal side (reverse side or side facing the user's skin), and waterproofing on the opposite side, and can advantageously have a three- dimensional reverse structure.

In particular, the invention relates to a hydrophilizing treatment of the lower or internal side (flesh side of the leathers) and waterproofing of the outer side (grain side of leathers, as well as a hydrophilizing treatment of the various types of synthetic microfibres (in this case, the hydrophilizing treatment can be printed on the outer side, on the internal side or on both sides of the fabric).

Moreover, the leathers and the fabrics can be supplied in full height or semifinished with pre-cut pieces.

Finally, microfibre leathers and fabrics can also undergo the application of a three- dimensional reverse structure (on the lower or internal side of the leather and/or fabric), by mechanical or pneumatic compression, thermo-forming, high-frequency or similar techniques, with the aim of permanently impressing the desired texture and allowing the presence of air channels on the internal side, thus favouring breathability and thermal comfort thanks to the reduction of contact points.

The invention is generally inserted in the field of tanning and textile treatments, in particular microfibre fabrics, and relates to a new type of process that can be used, in particular to make leather and fabrics hydrophilic in an eco-sustainable way, as well as the related products obtained.

The hydrophilizing treatment can be used equally on both the leathers and on microfibre fabrics, in particular on "Suede" microfibre fabrics (synthetic suede alternatives typically used in the world of technical footwear, but also in the automotive, furnishing and accessories sectors, such as handbags), and/or on microfibre finished with polyurethane and mixed films.

Moreover, the hydrophilizing treatment can be applied by means of vertical printing techniques in a localized manner or to full height, by applying a thermo-transferable films in localised areas or to full height or by silk-screen printing techniques or similar deposition techniques.

Currently, for example, the leathers for technical use have a water-repellent power given by a tanning process called retanning, but they do not have a high capacity to absorb the moisture produced by the body in the form of water vapour (in practice, that produced during sports activities).

Over time, the perspiration is absorbed by mechanical pressure due to the pressure of the body (so that it stagnates), creating areas impregnated with perspiration (defined as hot-spots in situations of high external temperature and cold-spots in the case of cold climates) which amplify the perceived thermal discomfort.

Moreover, both the traditional water-repellent leathers and the microfibre fabrics on the market have a certain hostility to absorb perspiration on the lower or inside or reverse side, due to the density of the fibres and the water-repellent and textile finishing treatments used.

If only the surface of the leather is to be waterproofed, silicone substances or fluorinated organic compounds can be used by means of spray techniques or by applying “on top”.

In industrial practice, substances are used which act in the aqueous phase and which at the same time are capable of lubricating the fibres of the leather. These substances are all composed of hydrophilic groups that can be emulsified in water and hydrophobic structures which give the leather water-repellent characteristics. However, in order to obtain the water-repellent effect, at the end of the application, the hydrophilic part must be blocked by heavy metal ions and it is necessary that the waterproofing product penetrates deeply into the entire section of the leather or fabric; a good penetration is obtained if the treatments that precede the application of the products anionize the skin or the fabric so as to provide the penetration in the entire surface, in a restricted bath and for a long time.

The main aim of the invention is therefore to provide a process for obtaining water/oil repellent fabrics and leathers by carrying out a hydrophilization treatment of one of the sides and, in particular, of the internal or lower side of the fabric or leather (side facing the user's epidermis, also called flesh side in leathers) and, advantageously, a waterproofing treatment of the opposite side; this process is able to overcome the drawbacks described above, solving the problems of the prior art, for example relating to the poor wettability of the lower side, not finished, to increase the performance of the leathers and fabrics in terms of breathability, transport and conveyance of perspiration or liquids limited to the functionalized surface. Another aim of invention is to provide an effective and economical process for the production of water/oil repellent fabrics and leathers, also conferring a dual functionality to the fabric or leather thanks to the absorbent properties of the internal or lower side (flesh side of the leather).

Another aim of the invention is to provide a process for the production of fabrics and leathers with hydrophilic properties on the functionalized part, which, thanks to the conformation adopted on the internal or lower side by applying a three- dimensional structure on the reverse side impressed in a permanent manner, which favours the presence of air channels on the internal side, have a high breathability and a considerable technical comfort, thanks to the reduction of the contact points. This three-dimensional structure can be impressed by mechanical or pneumatic compression, thermo-forming, high-frequency or similar techniques suitable for making the lower or internal side, facing the user's epidermis, three- dimensional.

In particular, the invention aims to provide a process which is economical, simple to perform and which is able to maintain high quality standards, without using harmful substances.

Another aim of the invention is to improve the health and safety of the plants for the treatment of fabrics and leathers, while at the same time increasing the quality of the environment for operators in the sector.

A further aim of the invention is to provide a process and a waterproofing product for leathers and fabrics that are versatile and therefore applicable to various types of leathers and fabrics, for different applications.

Advantageously, the invention relates to the application of specific wetting or hydrophilizing agents directly on the internal side of the leather or fabric, by means of vertical, rotary or cylinder printing techniques, by deposition through screen and/or pad printing systems, in high frequency or with similar techniques aimed at functionalizing the external side by diversifying the surface by means of graphic or full-field effects.

The hydrophilic wetting agents are generally composed of polysiloxane acids, carboxylic acid esters, silicone nano-emulsions, silicone micro-emulsions, silicone macro-emulsions, polyglycol ethers or polyglycolic ethers.

This process can be carried out by deposition on full-height fabrics or leathers or by localised deposition on finished pieces of leather or fabric; it can therefore be considered as semi-processing performed at a later time on pre-cut pieces and can be carried out directly on the fabric or during the entire tannery or textile finishing process.

The products used do not alter the water-repellent properties of finished and unfinished fabrics and leathers and significantly contribute to conveying the humidity over a larger surface to facilitate quick drying; consequently, the breathability of the fabric and leather is favoured, distributing the perspiration particles over a larger surface.

There are a multitude of uses and applications of the above-mentioned process, ranging from motor sport to furnishing, from the automotive sector to the nautical sector, as well as to leather goods, footwear, etc.

This invention will now be described by way of non-limiting example according to some of its preferred embodiments.

The process for the production of water/oil repellent fabrics and leathers, according to the invention, consists of the application on the above-mentioned leather or fabric of hydrophilizing materials, such as hydrophilic polysiloxane acids, esters of carboxylic acids, silicone nano emulsions, silicone micro emulsions, silicone macro emulsions, polyglycol ethers or polyglycolic ethers.

Advantageously, the above-mentioned process can be applied to microfibre fabrics (in particular "Suede" microfibre fabrics and synthetic microfibre finished with polyurethane and mixed films) and to the leathers during the whole tanning process and especially in the retanning, dyeing and fattening or final finishing phases; moreover, the hydrophilic treatment can be applied on the lower or internal side (flesh side of the leathers) or on synthetic microfibres by printing on the external side, on the internal side or on both sides of the fabric or applied by deposition using screen printing, pad printing, high frequency or similar techniques.

The hydrophilizing compounds are applied with variable percentages based on the weight and thickness of the leather and, advantageously, between 3% and 30% by weight, with a preferable and optimal value of 15% by weight; they are also advantageously applied on the leathers in the fattening phase or in the final finishing phase according to the desired softness of the leather.

In the case of application on leathers in the retanning phase, the compounds used are advantageously treated in an aqueous solution with dilutions 1 : 1 , 1 : 2, 1 : 3 and relative percentages on the dry weight of the leather, at temperatures of between 35 °C and 70 °C (based on the processing stage where they are introduced) and with pH values of between 3.5 and 7.5 (also with the aid of buffer solutions). The leather or fabric thus obtained can also be subjected to particular mechanical processes aimed at increasing its technical characteristics, such as, by way of a preferred, non-limiting example, ironing, pressing and/or conditioning, at temperatures of between 70°C and 120°C, in order to favour the polymerization reaction of the retanning agents.

In particular, the process according to the invention causes the microfibre fabric and the leather to be waterproofed against external atmospheric agents by means of water-repellent products characterised by the absence of perfluorinated treatments (PFC fluorocarbon compounds) and/or BTX (aromatic hydrocarbons). According to preferred but non-limiting embodiments, the types of leather to which the above-mentioned process, according to the invention, is applicable, can be raw splits, buffed leathers, full-grain leathers finished with a polyurethane base, aniline- based finished leathers, unfinished leathers, leathers of bovine, swine, goat, equine, marsupial origin, reptile skins, cartilaginous fish skins, etc.

Again advantageously, the invention also finds application in leathers defined by the "wet-blue", "wet white", "metal free", "chrome free" tanning processes, as well as on "Suede" microfibre fabrics and/or on microfibre finished with polyurethane and mixed films.

In particular, the above-mentioned water-repellent product or its hydrophilizing version can be applied by means of different methods, such as an application in aqueous solution by spraying or transferring or by means of an application from a support or cylinder; furthermore, advantageously in the case in which only the surface of the leather is to be waterproofed, silicone substances and/or fluorinated organic compounds can be used by spray technique or by applying on top.

The invention also relates to the manufacture of a product by means of the above- mentioned process and relates, in particular, to a microfibre fabric or a technical and eco-sustainable leather, intended, in particular, for automotive uses, clothing, footwear, furniture, leather goods.

The characteristics of the process for the production of water/oil repellent fabrics and/or leathers and of the relative product obtained, according to the invention, clearly emerge from the description, as do the advantages thereof.

The most relevant advantages include the following: low environmental impact and eco-compatibility, both of the compounds used and of the intermediate products which are generated; no possibility of carcinogenesis due to the products used; greater yield and durability of the fabric or leather; greater technical and physical strength; improved vapour permeability; improved health and safety in the workplace; ease of use of the compounds and the execution of the process; greater versatility of application; possibility of customising and modulating as desired the water repellence of the fabric and of the leather and its absorption by hydrophilicity on the reverse side; applicability of the process to the various stages of the tanning process; ease of storage and transport of the compounds; low costs by virtue of the advantages achieved.

The invention described can be modified and adapted in several ways without thereby departing from the scope of the inventive concept of the accompanying claims.

Moreover, all the details can be replaced by other technically-equivalent elements. Lastly, the components used, providing they are compatible with the specific use, may vary according to requirements and the state of the art.