WO2022023137A1 - Method for making a conductive coating containing graphene on natural or synthetic leather, and natural or synthetic leather thus obtained. - Google Patents
Method for making a conductive coating containing graphene on natural or synthetic leather, and natural or synthetic leather thus obtained. Download PDFInfo
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- WO2022023137A1 WO2022023137A1 PCT/EP2021/070341 EP2021070341W WO2022023137A1 WO 2022023137 A1 WO2022023137 A1 WO 2022023137A1 EP 2021070341 W EP2021070341 W EP 2021070341W WO 2022023137 A1 WO2022023137 A1 WO 2022023137A1
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/0056—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the compounding ingredients of the macro-molecular coating
- D06N3/0063—Inorganic compounding ingredients, e.g. metals, carbon fibres, Na2CO3, metal layers; Post-treatment with inorganic compounds
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
- D06N3/14—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes
- D06N3/145—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes two or more layers of polyurethanes
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
- D06N3/14—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
- D06N3/0011—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using non-woven fabrics
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
- D06N3/0015—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using fibres of specified chemical or physical nature, e.g. natural silk
- D06N3/0036—Polyester fibres
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- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/0086—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique
- D06N3/0095—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique by inversion technique; by transfer processes
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/0086—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique
- D06N3/0095—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique by inversion technique; by transfer processes
- D06N3/0097—Release surface, e.g. separation sheets; Silicone papers
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
- D06N3/14—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes
- D06N3/147—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyurethanes characterised by the isocyanates used
- D06N3/148—(cyclo)aliphatic polyisocyanates
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- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N2201/00—Chemical constitution of the fibres, threads or yarns
- D06N2201/02—Synthetic macromolecular fibres
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N2203/00—Macromolecular materials of the coating layers
- D06N2203/06—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D06N2203/068—Polyurethanes
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N2205/00—Condition, form or state of the materials
- D06N2205/12—Platelets, flakes
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- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N2209/00—Properties of the materials
- D06N2209/04—Properties of the materials having electrical or magnetic properties
- D06N2209/041—Conductive
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- D06N2211/00—Specially adapted uses
- D06N2211/10—Clothing
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- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N2211/00—Specially adapted uses
- D06N2211/12—Decorative or sun protection articles
- D06N2211/28—Artificial leather
Definitions
- the present invention relates to a method for making a conductive coating containing graphene on natural or synthetic leather, and to the natural or synthetic leather thus coated.
- substrates that are not naturally conductive, such as natural leather, tanned leather or natural or synthetic textile articles, electrically and/or thermally conductive by applying conductive substances such as graphene.
- WO 2015/103565 A1 describes the application of conductive inks containing graphene on a wide variety of substrates, including leather and tanned leather.
- the graphene can be present in any form, for example also as oxide, or can contain oxygen in any ratio with carbon, from 1:1 to 2000:1, or can be functionalized with hydroxyl, carboxyl or epoxy groups, or can be mixed with graphite in any ratio, from 1 to 99% by weight.
- the conductive ink can be applied with any method, such as painting, dyeing, powder coating, lamination, extrusion, electrodeposition, lithography and many others, but no specific examples of application are provided.
- WO 2020/002979 A1 describes a tanned leather treated so as to be thermally dispersive and electrically conductive, and the related treatment method.
- the method comprises direct impregnation of the tanned leather with an aqueous bath containing graphene particles after tanning the leather and before the finishing treatment of the tanned leather, by means of mixing in a drum.
- the graphene particles are thus trapped inside the voids of the collagen matrix of the tanned leather, which is then dried by heating to 70°C.
- CN 108330704A discloses a graphene superfine fibre polyurethane synthetic leather and a preparation method thereof.
- the graphene superfine fibre polyurethane synthetic leather comprises a surface layer, a middle layer and an adhesive layer.
- the synthetic leather is prepared from the following components: high-performance waterborne non-yellowing polyurethane resin, nylon, graphene, superfine fibre polyurethane synthetic substrate, abrasion-resistant agent, light-resistant agent, flame -retardant master batch and water.
- the preparation method comprises the steps of weighing the raw materials; treating the graphene; mixing and stirring the raw materials; filtering the solution by a filtering net, and preparing the leather by applying the components on a base cloth.
- CN 105735002A discloses polyurethane modified in-situ with graphene and a method for manufacturing synthetic leather with high physical properties.
- the graphene -modified polyurethane is characterized in that graphene is firstly subjected to lipophilic modification, then the modified graphene is dispersed in a polyurethane solution, and the modified polyurethane is prepared with traditional dry and wet processes.
- the polyurethane can be strengthened and toughened, and is applicable to manufacturing of various synthetic leather.
- US 2020/062914 A1 discloses a polyurethane film comprising a polyurethane resin and graphene, characterized in that said graphene is present in an amount of 1 to 30% by weight on the total weight of the film.
- the prior art embodiments do not provide an optimal solution to the problem of effectively maintaining the thermal and electrical dispersion properties of the tanned leather or of the synthetic leather over time.
- the graphene applied to the surface can be removed by rubbing and surface wear.
- an object of the present invention is to provide a method for making a thermally and electrically conductive coating on natural or synthetic leather which is stable and maintains its properties over time.
- Another object of the present invention is to provide a method for making a thermally and electrically conductive coating on natural or synthetic leather which is also adapted to give it surface finishes having particular aesthetic effects, both with regard to the presence of decorative patterns on the surface and with regard to the morphological structure of the surface.
- a further object of the invention is to provide a natural or synthetic leather provided with a thermally and electrically conductive coating, and optionally with decorative patterns on the surface and/or with a particular surface morphology.
- an aspect of the present invention concerns a method for making a thermally and electrically conductive coating containing graphene on natural leather or on a textile substrate for the production of synthetic leather, characterized in that it comprises the following steps: a) formation of an internal layer comprising one or more aliphatic polyurethanes, having a thickness from 10 to 50 pm, applied on said natural leather or said textile substrate; b) formation of one or more intermediate layers, each having a thickness from 10 to 50 pm, applied on said internal adhesive layer (A), said intermediate layers each comprising one or more aliphatic polyurethanes and graphene nano -platelets, wherein at least 90% of said graphene nano -platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein the C/O ratio is > 100:1; c) formation of an external layer comprising one or more aliphatic polyurethanes, having a thickness from 2 to 10 pm,
- Fig. 1 is a sectional schematic view of a first embodiment of a synthetic leather according to the invention.
- Fig. 2 is a sectional schematic view of a second embodiment of a synthetic leather according to the invention.
- thermo leather or “natural leather” is meant as the final product obtained by processing animal skin.
- the term “synthetic leather” or “leatherette” or “faux leather” is meant as a natural or synthetic textile substrate coated with a film of plastic material with a surface finish that imitates tanned leather or natural leather.
- the term “textile substrate” is meant as a substantially flat substrate such as a fabric, a nonwoven, a polymer film or membrane. With regard to fabric, it can be made of natural, artificial or synthetic fiber. With regard to the nonwoven and the polymer film or membrane, these are typically made with artificial fibers or synthetic resins.
- the natural or synthetic leather with the coating according to the present invention can be used in the manufacture of garments or other articles, for example in the furniture sector, such as seats, sofas and the like, including seats and seating in the automobile sector, where thermal and electrical dissipation properties are particularly advantageous.
- natural or synthetic leather with the coating according to the invention is capable of distributing the heat absorbed evenly, but also of ensuring breathability, so as to maximize the comfort of the user.
- the invention provides for applying a multi-layer coating as defined above, either directly on the natural leather, or tanned leather, or on a textile substrate adapted to produce synthetic leather.
- the textile substrate With regard to the material with which the textile substrate is made, it has been said that it can be a natural, artificial or synthetic material.
- the textile substrate is a nonwoven or a polymer film or membrane, the material of which it is formed is, as a rule, artificial or synthetic.
- Useful natural fibers include, for example, wool, silk and cotton.
- Useful artificial fibers include modified or regenerated cellulose fibers, such as viscose and cellulose acetate.
- Useful synthetic fibers comprise polyamide, including aromatic polyamides (aramids), polyester, polyurethane, polyacrylonitrile, polycarbonate, polypropylene, polyvinyl chloride and mixtures thereof.
- fabric obtained from blends of natural, artificial and synthetic fibers can advantageously be used.
- a coating is applied to a substrate 10 consisting of a textile or tanned leather substrate according to the following steps: a) formation of an adhesive internal layer (A) comprising one or more aliphatic polyurethanes, having a thickness from 10 toa 50 pm, in contact with said natural leather or with a textile substrate, followed by heating to a temperature between 70 and 100°C for a time between 1 and 10 minutes; b) formation of one or more intermediate layers (B), having a thickness from 10 to 50 mhi, superimposed on said adhesive internal layer (A), said intermediate layers (B) comprising one or more aliphatic polyurethanes and graphene nano -platelets, wherein at least 90% of said graphene nano -platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein
- a coating comprising the following layers is applied to a suitable textile substrate 20:
- an adhesive internal layer comprising one or more aliphatic polyurethanes, having a thickness from 10 to 50 pm, in contact with said natural leather or with a textile substrate;
- first intermediate layer (B) a first intermediate layer (B), having a thickness from 10 to 50 pm, superimposed on said adhesive internal layer (A), said first intermediate layer (B) comprising one or more aliphatic polyurethanes and graphene nano -platelets, wherein at least 90% of said graphene nano-platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein the C/O ratio is > 100: 1;
- the second intermediate layer (Bl) a second intermediate layer (Bl), having a thickness from 10 to 50 pm, applied to the first intermediate layer (B).
- the second intermediate layer (Bl) also comprises one or more aliphatic polyurethanes and graphene nano platelets, wherein at least 90% of said graphene nano -platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein the C / O ratio is > 100:1
- the intermediate layer (B) is advantageously present when the outermost layer (C) is formed with depressions and/or roughness that imitate the surface morphology of tanned leather.
- the depressions expose, or can expose, areas of the second intermediate layer B1 containing graphene, to the atmosphere, the presence of two intermediate layers (B) and (Bl) ensures the permanence of a sufficient amount of graphene in the coating, ensuring that the features of electrical and thermal dissipation are maintained.
- the various layers (A), (B), (Bl) and (C) both directly on the tanned leather or on the textile substrate, and indirectly, i.e., by carrying out deposition of the layers in reverse order (C), (Bl), (B) and (A) on an external support, for example a release paper.
- the layers thus deposited are then coupled to the tanned leather or to the textile substrate, with the layer (A) in contact therewith, and finally the release paper is detached, exposing the external layer (C).
- the invention relates to a method for making a thermally and electrically conductive coating containing graphene on natural leather or on a textile substrate for the production of synthetic leather, characterized in that it comprises the following steps: i. spreading an aqueous dispersion of one or more aliphatic polyurethanes on a paper substrate for producing said external layer (C), having a thickness from 2 to 10 pm, followed by heating to a temperature between 70 and 90°C for a time between 1 and 10 minutes; ii.
- said layer (C) spreading on said layer (C) an aqueous dispersion of one or more aliphatic polyurethanes and graphene nano -platelets, wherein at least 90% of said graphene nano-platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein the C/O ratio is > 100:1, for the formation of said intermediate layer (B) having a thickness from 10 to 50 pm, followed by heating to a temperature between 70 and 100°C for a time between 1 and 10 minutes; iii.
- the method also provides for a step ii ⁇ after the step ii., as follows: ii’.
- an aqueous dispersion of one or more aliphatic polyurethanes and graphene nano -platelets wherein at least 90% of said graphene nano-platelets has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and wherein the C/O ratio is > 100:1, for the formation of an intermediate layer (Bl) having a thickness from 10 to 50 pm, followed by heating to a temperature between 70 and 100°C for a time between 1 and 10 minutes.
- the method comprising the step ii’. leads to obtaining a coating comprising two intermediate layers (B) and (Bl), as defined above.
- the indirect deposition method is preferable in the case of producing the coating on the textile support.
- the method is in actual fact a method for making an artificial leather with features of thermal and electrical conductivity.
- the coating on the tanned leather or on the textile substrate in the first case it is not necessary to produce a surface finish that imitates tanned leather, although it might be desirable to give the tanned leather a particular surface finish. Instead, in the second case a surface finish that imitates leather must be created.
- Fig. 2 schematically shows the production of a surface finish of artificial leather on the outermost intermediate layer Bl, represented schematically by a series of triangles.
- the external layer (C) is applied by means of a cylinder engraved with a punctiform pattern filled with the material of the layer (C), which is deposited on the layer (Bl).
- Each of the layers (A), (B), (Bl) and (C) comprises as main component one or more aliphatic polyurethanes, present in an amount of at least 80% by weight of each single layer, preferably at least 90% by weight of each single layer.
- Each of the layers (A), (B), (Bl) and (C) further comprises one or more of the following components selected in the group consisting of: leveling agents, cross-linking agents and thickening agents.
- each layer comprises all of these agents.
- Leveling agents advantageously usable are fluorinated surfactants, or mixtures thereof.
- Cross-linking agents advantageously usable are polyethylene amines, or mixtures thereof.
- Thickening agents advantageously usable are natural or synthetic thickening agents.
- inorganic natural thickening agents are laminar silicates such as bentonite.
- organic natural thickening agents are proteins, such as casein or polysaccharides. Natural thickening agents chosen from agar agar, gum arabic and alginates are particularly preferred.
- Examples of synthetic thickening agents are generally liquid solutions of synthetic polymers, in particular poly acrylates.
- the graphene is present in the layer (B) or in the layer (Bl) in an amount from 0.5 to 15% by weight of the total weight of the layer, more preferably between 1.5 and 10% by weight, more preferably between 2 and 8% by weight.
- the graphene consists of graphene nano -platelets, wherein at least 90% has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm.
- At least 90% of the graphene nano -platelets has a lateral dimension (x, y) from 100 to 10000 nm and a thickness (z) from 0.34 to 10 nm, more preferably a lateral dimension (x, y) from 200 to 8000 nm, even more preferably between 500 and 5000 nm, and even more preferably a thickness (z) from 0.34 to 8 nm, more preferably from 0.34 to 5 nm.
- the graphene nano-platelets have a C/O ratio > 100: 1, preferably a C/O ratio > 200: 1.
- Graphene is a material consisting of a monatomic layer of hybridized carbon atoms in the form sp 2 . Therefore, they are arranged in close-packed, highly crystalline and regular hexagonal honeycomb structures.
- the Applicant Directa Plus S.p.A. is the owner of patents and patent applications relating to methods for producing structures comprising layers of graphene, such as EP 2 038 209 Bl, WO 2014/135455 A1 and WO 2015/193267 Al.
- the last two patent applications describe methods for producing dispersions of pristine graphene, from which it is possible to obtain graphene nano-platelets with the dimensions required for the implementation of the present invention, and with a C / O ratio > 100:1. This ratio is important as it defines the maximum amount of oxygen bonded to the carbon forming the graphene. In fact, the best properties of graphene, which derive from its high crystallographic quality are obtained when the amount of oxygen is minimum.
- a pristine graphene i.e., with a C/O ratio > 100. and having the dimensional features defined above is produced and marketed by Directa Plus S.p.A. with the brand name G+ ® .
- the C/O ratio in the graphene used in the method according to the invention is determined by means of elemental analysis performed by elemental analyzer (CHNS O), which provides the weight percentage of the various elements. By normalizing the values obtained with respect to the atomic weight of the C and O species and finding their ratio, the C/O ratio is obtained. It was found that the graphene in oxidized form, just as the graphene in the form obtained through reduction of graphene oxide (“GO”), has different features and properties to pristine graphene. For example, the features of electrical and thermal conductivity and those of mechanical strength of the pristine graphene are higher than those of GO and than the reduction product obtained therefrom, also due to the presence of numerous reticular defects and imperfections of the crystalline structure caused by the reduction reaction.
- CHNS O elemental analyzer
- the reticular defects of the nano-platelets can be evaluated using Raman spectroscopy by analyzing the intensity and shape of the Peak D positioned at 1350 cm 1 .
- the process for producing pristine graphene is carried out continuously, by continuously feeding the graphite flakes to the high temperature expansion step, continuously discharging the so-obtained expanded graphite in an aqueous medium and continuously subjecting the expanded graphite dispersed in the aqueous medium to exfoliation and size reduction treatment carried out with the methods of ultrasonication and/or homogenization at high pressure.
- the final dispersion of the graphene nano-platelets obtained can be concentrated or dried, depending on the final form required for the graphene.
- the object of drying the dispersion is to obtain a dry powder that is easily redispersible in various matrices, both solvents and polymers, where liquid is not desirable or manageable at process level, or where water cannot be used due to chemical incompatibility.
- a significant advantage of the production processes described in the patent documents WO 2014/135455 A1 and WO 2015/193267 A1 consists in the possibility of operating without using surfactants.
- the graphene nano -platelets thus obtained are highly pristine, both due to the high C/O ratio and due to the absence of foreign substances that could contaminate them, such as surfactants.
- the absence of surfactants allows graphene having an electrical conductivity substantially higher than the graphene obtained with processes that use surfactants to be obtained. This improves the performance of the graphene in many applications.
- the pristine graphene nano-platelets at least 90% of which has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, having a C/O ratio > 100:1, have a high electrical conductivity. It has also been seen that when a dispersion of graphene nano platelets is formed in the presence of surfactant, this deposits on the surface thereof and tends to promote its agglomeration.
- the dimension of the graphene nanoplatelets is defined with reference to a system of Cartesian axes x, y, z, it being understood that the particles are substantially flat platelets but can also have an irregular shape.
- the lateral dimension and the thickness provided with reference to the directions x, y and z must be intended as the maximum dimensions in each of the aforesaid directions.
- the lateral dimensions (x, y) of the graphene nano -platelets are determined, within the scope of the production process described above, with direct measurement using the scanning electron microscope (SEM), after diluting the final dispersion in a ratio of 1:1000 in deionized water and pouring it dropwise onto a silicon oxide substrate arranged on a plate heated to 100°C.
- SEM scanning electron microscope
- nano-platelets are available in dry state, SEM analysis is carried out directly on the powder deposited on a double-sided carbon adhesive tape. In both cases, the measurement is carried out on at least 100 nano -platelets.
- AFM Atomic Force Microscope
- the thickness (z) can be measured using a dispersion of nano -platelets diluted in a ratio of 1:1000 in isopropanol, from which 20 ml is collected and subjected to sonication in an ultrasonic bath (Elmasonic S40) for 5 minutes.
- the nano-platelets are then deposited as described for SEM analysis and are scanned directly with an AFM tip, where the measurement provides a topographical image of the graphene flakes and their profile with respect to the substrate, enabling precise measurement of the thickness.
- the measurement is carried out on at least 50 nano-platelets.
- nano-platelets in dry state are available, the powder is dispersed in isopropanol at a concentration of 2 mg/L, from which 20 ml is collected and subjected to sonication in an ultrasonic bath (Elmasonic S40) for 30 minutes. The nano-platelets are then deposited as described for SEM analysis and scanned using AFM.
- At least 90% of the graphene nano-platelets preferably has a lateral dimension (x, y) from 50 to 50000 nm and a thickness (z) from 0.34 to 50 nm, and a C/O ratio > 100:1.
- At least 90% of the graphene nano-platelets has a lateral dimension (x, y) from 100 to 10000 nm and a thickness (z) from 0.34 to 10 nm, more preferably a lateral dimension (x, y) from 200 to 8000 nm, and even more preferably between 500 and 5000 nm, and preferably a thickness (z) from 0.34 to 8 nm, more preferably from 0.34 to 5 nm.
- the dispersion for application on the tanned leather or on the textile substrate of the invention for the formation of each of the layers (A), (B), (Bl) and (C) is in thick liquid or paste form, where the dispersing liquid is preferably water or a mixture of water with other solvents and/or dispersants.
- thick liquid or paste are meant as an aqueous dispersion containing from 20 to 70% by weight of solids, preferably from 25 to 60% by weight of solids, more preferably from 30 to 50% by weight of solids.
- this dispersion at least 90% by weight of the solids consists of aliphatic polyurethane and of the graphene nano -platelets.
- the aqueous dispersion for the formation of each of the layers (A), (B), (Bl) and (C) further comprises, as said above, one or more components selected in the group consisting of leveling agents, cross-linking agents and thickening agents.
- the aqueous dispersion of aliphatic polyurethane comprises al these agents.
- the aqueous dispersion for the formation of the layer (B) or of the layer (Bl) comprises from 0.5 to 15% by weight of graphene nano-platelets, more preferably from 1 to 10% by weight, more preferably from 1.4 to 8% by weight.
- the aqueous dispersion is prepared by mixing the aliphatic polyurethane or the aliphatic polyurethanes with one or more of the other components, as defined above.
- Preparation of the aqueous dispersion is carried out preferably introducing the polyurethane pre-dispersed in water into a receptacle stirred with a rotary stirrer, into which the graphene and the leveling, cross-linking and thickening agents are then introduced.
- the dispersion is stirred until obtaining a uniform dispersion.
- stirring takes place at a rotation speed of the stirrer between 1000 and 2500 rpm (rounds per minute) for a time from 1 to 2 hours.
- the viscosity of the composition is preferably in the range between 10000 and 20000 cPs, or mPa-s.
- the viscosity is regulated also by means of the amount of thickening agent.
- Application of the dispersion on the substrate and/or on each layer of the previously formed coating is followed by a step of heating the layer to an increasing temperature between 70 and 100°C, for a time between 2 and 10 minutes. After producing the last layer, heating takes place at a higher temperature, from 100 to 160°C, preferably from 120 to 160°C, to carry out cross-linking of the components and curing of the layer.
- the heating step is carried out in two ovens in succession.
- the external layer (C) is produced with depressions or roughness suitable to provide a handle similar to that of tanned leather.
- imitation of tanned leather through the formation of depressions or roughness takes place directly on the intermediate layer (B) or (Bl), as for example shown in Fig. 2, depositing this layer on a release paper provided with depressions and/or roughness.
- a protective external layer (C) is then deposited on the layer (Bl) thus formed, for example with a treatment consisting in applying the external layer (C) by means of a cylinder engraved with a punctiform pattern filled with the material of the layer (C), which is deposited on the layer (Bl), as shown in Fig. 2.
- the total thickness of the coating comprising all the layers is between 42 and 160 pm, preferably between 45 and 120 pm, more preferably between 47 and 90 pm.
- thermal conductivity greater than 1 W/mK It must be considered that the thermal conductivity of a metal is generally > 20 W/mK, and that of the insulating polymers is generally ⁇ 0.1 W/mK.
- dispersion on the tanned leather or on the textile substrate makes it possible to obtain a coating that is substantially electrically and thermally dissipative.
- the coating also makes it possible to imitate tanned leather, hence to obtain an electrically and thermally dissipative imitation leather. Therefore, the article thus obtained can advantageously be used for the production of articles in the clothing and furniture sector, including seats and seating for the automobile sector.
- the graphene consisted of nano-platelets produced by Directa Plus, dispersed in paste form (Paste G+) in the aqueous dispersion of the polyurethanes PU 1 and PU 2.
- the Paste G+ utilized was composed of 23.5% water and 76.5% graphene nano-platelets (Pure G+). Moreover, a cross-linking agent, X-LINK 100 (dry residue 99%; polyaziridine) and a leveling agent, LEV 3F (dry residue 3.5-5.5; mixture of fluorinated surfactants) were also used.
- the Paste G+ was dispersed in the polyurethanes using a Cowles Dissolver DISPERMAT® CN40 disperser. The specifications of the instrument are: power 2.2 kW; rotation speed 0 - 5500 rpm (rounds per minute); torque 7.2 Nm. The material was treated for 15 minutes at 4000-5000 rpm (rounds per minute). The dispersion produced contained 5% of graphene G+.
- Textile substrate 10 nonwoven in polyester microfiber.
- the layer (C) is spread on a release paper giving an aesthetic effect with organic geometries imitating a natural leather. Coating takes place on a release paper.
- the total weight of the coating is 58 g/m 2 .
- the amount of graphene in the coating is 0.51 g/m 2 , equal to 0.9%.
- Textile substrate 20 nonwoven in polyester microfiber.
- the layer (C) is applied on the layer (Bl) with the “mille punti” method, as described above, as final treatment when the other layers have been produced and coupled to the textile substrate.
- the layer (B) It is spread on the layer (B). It is heated in a first oven to 110°C, coupled to the textile substrate and heated in a second cross-linking and curing oven to 150°C.
- the total weight of the coating is 142 g/m 2 .
- the amount of graphene in the coating is 2.55 g/m 2 , equal to 1.8%.
Abstract
Description
Claims
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KR1020237006413A KR20230048068A (en) | 2020-07-29 | 2021-07-21 | Method for producing a conductive coating containing graphene on natural or synthetic leather, and the natural or synthetic leather thus obtained |
CN202180058682.XA CN116157570A (en) | 2020-07-29 | 2021-07-21 | Method for preparing conductive coating containing graphene on natural or synthetic leather and natural or synthetic leather obtained by same |
EP21749789.0A EP4189156A1 (en) | 2020-07-29 | 2021-07-21 | Method for making a conductive coating containing graphene on natural or synthetic leather, and natural or synthetic leather thus obtained |
US18/018,612 US20230295870A1 (en) | 2020-07-29 | 2021-07-21 | Method for making a conductive coating containing graphene on natural or synthetic leather, and natural or synthetic leather thus obtained |
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EP (1) | EP4189156A1 (en) |
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Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2038209B1 (en) | 2006-06-08 | 2012-08-15 | Directa Plus S.p.A. | Production of nano-structures |
WO2014135455A1 (en) | 2013-03-06 | 2014-09-12 | Directa Plus S.P.A. | Concentrated water dispersion of graphene and method for the preparation thereof |
WO2015103565A1 (en) | 2014-01-05 | 2015-07-09 | Vorbeck Materials | Coated leather articles and method of preparation |
WO2015193267A1 (en) | 2014-06-20 | 2015-12-23 | Directa Plus S.P.A. | Continuous process for preparing pristine graphene nanoplatelets |
CN105735002A (en) | 2016-03-07 | 2016-07-06 | 四川大学 | Graphene in-situ modified polyurethane and method for manufacturing synthetic leather with high physical properties |
CN108330704A (en) | 2018-02-02 | 2018-07-27 | 天守(福建)超纤科技股份有限公司 | A kind of graphene superfine fiber polyurethane leather and preparation method thereof |
WO2020002979A1 (en) | 2018-06-28 | 2020-01-02 | Gruppo Mastrotto S.P.A. | Thermally dispersing and electrically conductive processed leather |
US20200062914A1 (en) | 2017-05-05 | 2020-02-27 | Directa Plus S.P.A. | Polyurethane film comprising graphene and preparation process thereof |
-
2021
- 2021-07-21 KR KR1020237006413A patent/KR20230048068A/en unknown
- 2021-07-21 CN CN202180058682.XA patent/CN116157570A/en active Pending
- 2021-07-21 EP EP21749789.0A patent/EP4189156A1/en active Pending
- 2021-07-21 WO PCT/EP2021/070341 patent/WO2022023137A1/en active Application Filing
- 2021-07-21 US US18/018,612 patent/US20230295870A1/en active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2038209B1 (en) | 2006-06-08 | 2012-08-15 | Directa Plus S.p.A. | Production of nano-structures |
WO2014135455A1 (en) | 2013-03-06 | 2014-09-12 | Directa Plus S.P.A. | Concentrated water dispersion of graphene and method for the preparation thereof |
WO2015103565A1 (en) | 2014-01-05 | 2015-07-09 | Vorbeck Materials | Coated leather articles and method of preparation |
WO2015193267A1 (en) | 2014-06-20 | 2015-12-23 | Directa Plus S.P.A. | Continuous process for preparing pristine graphene nanoplatelets |
CN105735002A (en) | 2016-03-07 | 2016-07-06 | 四川大学 | Graphene in-situ modified polyurethane and method for manufacturing synthetic leather with high physical properties |
US20200062914A1 (en) | 2017-05-05 | 2020-02-27 | Directa Plus S.P.A. | Polyurethane film comprising graphene and preparation process thereof |
CN108330704A (en) | 2018-02-02 | 2018-07-27 | 天守(福建)超纤科技股份有限公司 | A kind of graphene superfine fiber polyurethane leather and preparation method thereof |
WO2020002979A1 (en) | 2018-06-28 | 2020-01-02 | Gruppo Mastrotto S.P.A. | Thermally dispersing and electrically conductive processed leather |
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US20230295870A1 (en) | 2023-09-21 |
EP4189156A1 (en) | 2023-06-07 |
KR20230048068A (en) | 2023-04-10 |
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