WO2020202075A1

WO2020202075A1 - Multi-layer composite material and its production method

Info

Publication number: WO2020202075A1
Application number: PCT/IB2020/053164
Authority: WO
Inventors: Lorenzo Lorenzi
Original assignee: Lorenzi S.r.l.
Priority date: 2019-04-02
Filing date: 2020-04-02
Publication date: 2020-10-08

Abstract

A multi-layer material (100) comprising a first and a second cover layer (1, 1") made of coagulated microfibre and at least one support layer (2) made of thermoplastic polymeric material chosen from a group comprising EVA, TPU or mixtures thereof, wherein said support layer (2) is placed between said first and second cover layers (1, 1") made of coagulated microfibre and is coupled to the first and second cover layers (1, 1") made of coagulated microfibre by lamination without the help of adhesives, wherein said coagulated microfibre is made of non-woven fabric; a method for producing a multi-layered material (100, 100') comprises the following steps: forming at least a first and a second cover layer made of polymeric microfibre material, impregnating the first and second microfibre cover layers with a polyurethane resin, and subjecting the first and second cover layers of impregnated microfibre to coagulation so as to obtain two coagulated microfibre cover layers (1, 1", 10'), forming a mixture comprising thermoplastic polymeric material, said thermoplastic polymeric material being chosen from a group comprising EVA, TPU or mixtures thereof, extruding said mixture onto one of the first or the second coagulated microfibre cover layer (1, 1", 10') so as to form a film of polymeric material on the first cover layer (1, 1", 10'), the extrusion step being conducted at a temperature between 120°C and 200°C, applying the second coagulated microfibre cover layer (1") to the thermoplastic polymeric film so that said film is placed between the first and second coagulated microfibre cover layers (1, 1", 10'), laminating the cover layers (1, 1", 10') and the support layer (2) so as to couple the cover layers (1, 1", 10') to the support layer (2) so as to obtain a multi- layer material (100) in which the two opposing visible faces (S, S') are made of the first and the second coagulated microfibre cover layers (1, 1", 10'), respectively, and in which the support layer (2) is coupled by lamination to the first and second coagulated microfibre cover layers (1, 1", 10') without the use of adhesives.

Description

MULTI-LAYER COMPOSITE MATERIAL AND ITS PRODUCTION METHOD

The present invention relates to a multi-layer material and particularly a multi-layer material which can withstand fraying and snagging.

The invention relates in particular to a thermoformable multi-layer material.

The material of the invention is particularly intended for the production of footwear inserts and components, preferably inserts and components for footwear uppers and components for leather goods, rigid backpack shells, boxes, eyeglass cases, and rigid parts of athletic footwear.

The invention also relates to a method for producing a multi-layer material.

Multi-layer materials made by coupling together two or more layers of identical materials or different materials are known.

Often, the objective is to produce multi-layer materials with layers made of materials having different mechanical and chemical properties so as to take advantage of the individual properties of the material in each layer.

One problem with multi-layer materials in which the various layers are made of different materials is achieving good adhesion between adjacent layers.

This problem is particularly evident for multi-layer materials in which the layers are made of non- woven fabric.

In order to optimize adhesion between layers, adhesives are used between the layers to be coupled together to make the multi-layer material. Such adhesives must have a good affinity for the materials of both layers to be coupled.

Usually, in a multi-layer material, an adhesive is usually provided between each pair of adjacent layers to be coupled.

The adhesives used generally have a high environmental impact, since they are made of highly polluting substances. For example, many adhesives produce toxic compounds when heated.

This creates a multitude of problems, thus limiting the use of multi-layer materials under certain conditions, for example where high temperatures may develop.

In addition, this complicates the disposal of multi-layer materials at the end of their useful life.

Also, due to their intrinsic limits, some types of adhesives cannot be used for certain purposes, such as for materials that need to withstand very high or very low temperatures, or high-humidity conditions, and the like.

This increases the usage limits of multi-layer materials in which the various layers are coupled together by means of suitable adhesives.

In addition, providing a layer of adhesive between two adjacent layers of the multi-layer material considerably complicates the process of producing the multi-layer material, because the process must allow for an adhesive application phase for each pair of layers to be coupled. In some cases, a drying phase for drying the adhesive must also be included.

Consequently, there is a need to provide a multi-layer material in which the layers are securely coupled together and which, at the same time, has a reduced environmental impact.

Furthermore, materials made of polymeric microfibre are widely used for a broad variety of purposes.

Microfibre materials have a very high softness that makes the materials particularly desirable, especially for certain uses. However, this feature makes microfibre materials unsuitable for use in instances where objects having a certain rigidity need to be made.

Indeed, due to intrinsic limits of the microfibre, such materials cannot undergo thermoforming processes aimed at, for example, making an object or body having a stable shape. Indeed, microfibres usually have a high level of flexibility and, conversely, very limited rigidity, and cannot undergo thermoforming.

Consequently, such materials cannot be used in cases where materials having a certain rigidity that can be thermoformed and hold the desired shape are needed.

One object of the invention is to provide a multi-layer material that overcomes the limitations discussed with regard to the cited prior art.

One object of the invention is to provide a multi-layer material having high mechanical strength properties.

Another object of the invention is to provide a multi-layer material having, at the same time, high softness and a certain rigidity, allowing the material to be thermoformed and to hold the desired shape.

Another object of the invention is to provide a multi-layer material that is not subject to fraying and/or snagging phenomena.

Another object of the invention is to provide a multi-layer material that has a limited environmental impact.

These and other purposes are achieved by the multi-layer material produced according to claim 1. One object of the invention is to provide a method for producing a multi-layer material that overcomes the limitations discussed with regard to the cited prior art.

In particular, one object of the invention is to provide a method for producing a multi-layer material that requires reduced time and cost and that, at the same time, achieves good adhesion between the various layers of the multi-layer material.

These objects are achieved by a method according to claim 10.

In one aspect of the invention, a multi-layer material is provided which comprises a first and a second cover layer made of coagulated microfibre and at least one support layer made of thermoplastic polymeric material chosen from a group comprising EVA, TPU, or mixtures thereof, wherein the support layer is placed between the first and second cover layers made of coagulated microfibre and is coupled to said first and second cover layers made of coagulated microfibre by lamination without the help of adhesives.

The coagulated microfibre is made of a non-woven fabric.

The material of the support layer is extruded directly onto one of the two cover layers and the resulting intermediate material is then subjected to lamination so as to compress the cover layers and the support layer together in order to couple the support layer to the cover layers.

In this way, stable adhesion between the cover layers and the support layer is achieved without the use of adhesives.

In the multi-layer material of the invention, the support layer made of thermoplastic polymeric material is placed between the two cover layers. This optimizes the properties of the multi-layer material of the invention.

The thermoplastic polymeric material of the support layer is chosen from a group comprising thermoplastic polyurethane and EVA.

In another version, the thermoplastic polymeric material of the support layer is a mixture of thermoplastic polyurethane and EVA comprising X% thermoplastic polyurethane and (100-X)% EVA.

By suitably setting the percentages of EVA and TPU in the support layer, it is possible to control the final hardness of the multi-layer material of the invention.

Advantageously, the support layer comprises expanded thermoplastic polyurethane

Advantageously, the support layer is coupled by direct extrusion to the cover layers made of microfibre.

By means of an extruder head, preferably a flat extruder head, a film of a mixture of thermoplastic polymeric material is extruded onto a cover layer of coagulated microfibre, and then the three layers, i.e. the two cover layers and the support layer, are laminated so as to be coupled together.

The lamination is advantageously performed by lamination rollers.

In a preferred embodiment, the support layer is directly coupled to at least one of the two cover layers of coagulated microfibre without any other material placed in between and without adhesives. In another preferred embodiment, the support layer is directly coupled to both cover layers of coagulated microfibre without any other material placed in between and without adhesives.

Generally, a layer of adhesive is placed between the layers to make them adhere to each other, but this is not done in the material of the invention.

The multi-layer material of the invention resists fraying and/or snagging and can be sewn.

The multi-layer material of the invention is at the same time flexible and strong, particularly in terms of tensile strength.

Both visible faces of the material of the invention are made of microfibre, with the support layer being placed between the two cover layers.

In the material of the invention, the presence of two outer cover layers of microfibre that form the outer layers of the multi-layer material of the invention provide a multi-layer material that can then be easily coupled to various materials, such as leathers or other coverings

In addition, the cover layers provide the multi-layer material of the invention with a soft, downy, and wrinkle-free characteristic that is ideal for enhancing the properties of coverings used in the leather goods and footwear sector.

On the other hand, the presence of the inner support layer made of polymeric material provides the material of the invention with a certain firmness and rigidity

The presence of the inner support layer made of thermoplastic polymeric material also allows the multi-layer material of the invention to be irreversibly thermoformed.

Advantageously, the multi-layer material of the invention is hot-pressed to give it a desired shape that is sustained after the pressure and temperature are removed.

This also makes it possible to use the multi-layer material of the invention in applications in which a microfibre material could not be used if it were not thermoformable and/or soft enough.

This also makes it possible to use the multi-layer material of the invention in applications requiring the forming of objects in a desired shape that is stable over time.

In the material of the invention, the presence of two outer cover layers of microfibre that form the outer layers of the multi-layer material of the invention makes it possible to subject the multi-layer material of the invention to thermoforming operations conducted at high temperatures. Indeed, the thermoforming can be performed at the softening point of the thermoplastic material of the support layer.

The thermoforming of the multi-layer material of the invention can be performed at a temperature greater than the softening point of the thermoplastic material of the support layer.

The presence of the microfibre cover layers keeps the thermoplastic material from leaking out during thermoforming. Indeed, in the event of partial melting of the thermoplastic material of the multi layer material during thermoforming, the thermoplastic material is absorbed by the microfibre in the cover layers and does not come out of the material.

This avoids damage to the thermoforming equipment

This absorption allows the structure of the resulting thermoformed object to be made firmer, creating a more stable bond between the layers of the multi-layer material.

The presence of the two microfibre cover layers allows thermoforming to be done at a high temperature, and therefore makes the thermoforming process faster.

The presence of the two microfibre cover layers furthermore simplifies the thermoforming process The multi-layer material of the invention has high properties of adhesion to various materials, such as leathers and other fabrics.

The multi-layer material of the invention is particularly well suited to the production of garments, parts of garments, footwear, parts of footwear, reinforcements for garments and/or footwear, bags and suitcases, parts of bags and suitcases, and belts.

The multi-layer material of the invention is also suitable for making cases for various objects, backpack shells or parts thereof, bag shells or parts thereof, and hats.

The material of the invention has a low cost and a low environmental impact, since, by extruding the support layer between the microfibre cover layers and subsequently laminating the resulting material to couple them together, the use of glues or adhesives is avoided and the production process is simplified. In one version, the support layer is made of closed-cell thermoplastic polyurethane foam.

The support layer made of expanded thermoplastic polyurethane preferably has a hardness from 50 to 90 Shore A, preferably 60-70 Shore A.

The support layer made of expanded thermoplastic polyurethane preferably has a thickness from 0.2 to 2.0 mm, preferably 0.5-1.2 mm, and even more preferably about 0.7-1.0 mm.

In one version, the support layer is made of EVA and preferably has a hardness from 25 to 70 Shore A, preferably 30-50 Shore A.

The EVA support layer preferably has a thickness from 0.2 to 2.0 mm, preferably 0.3-1.2 mm, and even more preferably about 0.5 mm.

In another embodiment, the support layer is made of X% TPU and (100-X)% EVA.

The hardness of the multi-layer material of the invention is adjusted by varying the percentages of EVA and TPU in the support layer.

The cover layers made of coagulated microfibre are preferably made of a polyamide microfibre and advantageously comprise about 40-60 wt.% of polyamide and about 40%-60 wt.% of polyurethane, preferably about 45-55 wt.% of polyamide and about 45-55 wt.% of polyurethane, and even more preferably about 50 wt.% of polyamide and about 50 wt.% of polyurethane.

It is preferable for the composition of each coagulated microfibre cover layer to be made of about half polyamide and about half polyurethane.

Nylon 6 fibres are preferably used for the microfibre cover layers.

The thickness of the coagulated microfibre cover layer is preferably from 0.3 mm to 2.1 mm, and in a particularly preferred embodiment from 0.9 mm to 1.3 mm.

Advantageously, the microfibre cover layer is made of coagulated non-woven polyamide microfibre fabric.

Advantageously, the microfibre of the invention has a structure with a polyurethane matrix in which the polyamide fibres are embedded. In one version, the material of the invention furthermore comprises a reinforcement layer made of fabric positioned so as to be between the first and second coagulated microfibre cover layers and the support layer made of thermoplastic polymeric material.

The presence of the reinforcement fabric layer makes the material of the invention particularly stable under tension, making it possible to obtain a material that is particularly well suited for uses such as shoulder straps or belts.

The reinforcement layer is coupled to the microfibre cover layer by suitable adhesives.

This produces a cover layer comprising an outer cover layer made of coagulated microfibre, intended to form one of the visible faces of the material of the invention, and a reinforcement layer made of fabric.

In another embodiment, the reinforcement layer is made of non-woven fabric.

Advantageously, the reinforcement fabric layer has an orthogonal fabric structure with a weight of 30 to 150 gsm, preferably 70-80 gsm.

The reinforcement fabric layer is advantageously made of PA or PL fibres

The presence of the fibrous reinforcement layer increases the tensile stability of the multi-layer material of the invention.

In a preferred embodiment, the reinforcement layer is at least partially embedded in the microfibre cover layer so that the support layer is coupled directly to the microfibre cover layer at least in some coupling regions, including in the presence of the support layer.

In another embodiment, both cover layers are provided with an outer coagulated microfibre layer and a reinforcement layer made of non-woven fabric placed so as to be between the support layer made of thermoplastic polymeric material and the corresponding outer layer of the corresponding cover layer.

The multi-layer material of the invention is preferably supplied in tape form advantageously wound onto spools. Tape material is understood as a material having two size dimensions that are considerably greater than the third dimension, the thickness.

In another aspect of the invention, a shaped object is provided, said object having a three- dimensional form obtained by shaping the multi-layer material of the invention by thermoforming, wherein the object is delimited by wall portions extending along planes that are mutually transversal. Subjecting the multi-layer material of the invention to thermoforming at a certain temperature causes the material of the support layer to soften, the multi-layer material is shaped into the desired shape by a suitable mould, and an object is obtained which, after cooling, keeps the desired shape while also maintaining a certain flexibility.

Preferably, the wall portions of the object are shaped so as to define at least one concave portion defining a housing space.

Preferably, the object has a concave shape so as to define a housing space.

The thermoformed object may be a case, such as for eyeglasses or stationery, a portion of a shell of a backpack, or bag, a hat, etc.

In yet another aspect of the invention, a method is provided for producing a multi-layer material, comprising the following steps:

forming at least two microfibre layers of polymeric material,

impregnating the at least two microfibre layers with a polyurethane resin and subjecting the impregnated microfibre cover layers to coagulation so as to obtain two coagulated microfibre layers,

forming a mixture comprising thermoplastic polymeric material, said thermoplastic polymeric material being chosen from a group comprising EVA, TPU, or mixtures thereof, extruding said mixture onto one of the first or the second coagulated microfibre cover layer so as to form a film of polymeric material on the first cover layer, the extrusion step being conducted at a temperature between 120°C and 200°C; applying said second coagulated microfibre cover layer to said thermoplastic polymeric film so that said film is placed between said coagulated microfibre cover layers

laminating said cover layers and said thermoplastic polymeric film so as to couple said cover layers to said thermoplastic polymeric film without the use of adhesives so as to obtain a multi-layer material in which the two opposing visible faces are made of the first and the second coagulated microfibre cover layers, respectively, and in which the support layer is coupled by lamination to the first and the second coagulated microfibre cover layers without the use of adhesives.

The extrusion temperature is chosen based on the polymeric material used to make the thermoplastic polymeric film.

The extrusion temperature is greater than the softening point of the mixture of polymeric material, so that the extruded mixture can be easily applied to the cover layer.

Lamination takes place when the mixture of polymeric material reaches a temperature greater than the softening point so as to promote and facilitate adhesion between the support layer and the cover layers.

Advantageously, the lamination step is conducted after about 3-10 s, preferably 6-8 s, after extrusion of the mixture of polymeric material.

The mixture of polymeric material is extruded directly onto the first layer of coagulated microfibre, the second layer is laminated after a period of 3-10 s, preferably 6-8 s, so that the cover layers and the support layer are coupled together.

With the method of the invention, a multi-layer material is obtained with good flexibility and, at the same time, high mechanical strength in which the support layer is stably coupled to the cover layers. In addition, the support layer is coupled directly, that is without the use of adhesives, to the first and second microfibre cover layer.

The coagulated microfibre cover layers and the support layer of thermoplastic material are laminated so as to be coupled to each other. The lamination takes place immediately after the extrusion step, with the two steps being conducted at the same time.

The feature of so-called direct extrusion of the polymeric film onto the cover layer with direct lamination of the layers achieves a very stable coupling between the support layer of thermoplastic material and the microfibre cover layers.

The extrusion is conducted at an extrusion temperature at which the thermoplastic material is a viscous fluid that tends to penetrate into the structure of the microfibre cover layer.

This effect is augmented by the use of an extruder head that expels the thermoplastic polymeric film onto the microfibre cover layer while maximizing the penetration of the thermoplastic polymeric material into the structure of the microfibre cover layer.

Consequently, a stable physical bond is created between the microfibre cover layers and the thermoplastic polymeric support layer.

At the same time, direct extrusion simplifies the method for producing the multi-layer material of the invention and reduces the environmental impact of the multi-layer material of the invention

Advantageously, the extrusion step is conducted with a flat-head extruder.

In a preferred embodiment, the mixture of thermoplastic polymeric material is formed by EVA or TPU or mixtures thereof. In one version, the mixture of polymeric material is formed by X% TPU and (100-X)% EVA.

The rigidity of the support layer is adjusted by varying the percentages of EVA and TPU in said layer; a finished product with a softer structure is obtained using EVA, whereas a more rigid and more supported product is obtained using TPU.

In another embodiment, the mixture is formed by EVA, or TPU, or TPU and a blowing agent to cause the thermoplastic polyurethane present in the mixture to expand during extrusion.

In this case, extrusion is conducted at a temperature between 120°C and 200°C so as to expand the thermoplastic polyurethane to obtain a support layer made of expanded thermoplastic polyurethane during said extrusion step that is placed between the two microfibre cover layers.

Using a flat-head extruder for the extrusion optimizes the expansion of the thermoplastic polyurethane and maximizes the adhesion of the expanded thermoplastic polyurethane to the support layer.

In one version, the method of the invention comprises subjecting the multi-layer material to thermoforming processes to obtain an object having a desired shape.

The thermoforming processes make it possible to advantageously obtain a shaped object having a three-dimensional form obtained by shaping the multi-layer material of the invention, wherein the shaped object is delimited by wall portions extending along planes that are mutually transversal Subjecting the multi-layer material of the invention to thermoforming at a certain temperature causes the material of the support layer to soften, the multi-layer material is shaped into the desired shape by a suitable mould, and an object is obtained which, after cooling, keeps the desired shape while also maintaining a certain flexibility.

The corner regions of the walls of the object are less flexible than the walls. Similarly, the regions of curvature variation of the object are less flexible than the walls of the object.

Consequently, the object keeps a desired shape while still having flexible walls.

Preferably, the object has a concave shape so as to define a housing space.

The thermoformed object may be a case, such as for eyeglasses or stationery, a portion of a shell of a backpack, or bag, a hat, etc. In one version, the method additionally comprises a reinforcement step in which a reinforcement layer made of fabric is applied to one of the two coagulated microfibre cover layers by means of a suitable adhesive.

The reinforcement layer is applied to the microfibre cover layer so as to be placed between the microfibre cover layer and the support layer of thermoplastic polymeric material. The reinforcement step is conducted upstream of the extrusion step.

The reinforcement fabric layer is advantageously made of PA or PL fibres.

In one version, the reinforcement fabric layer can be a non-woven fabric.

In one version, the reinforcement fabric layer is a fabric with an orthogonal weft.

The enclosed tables show, as a non-limiting example, two separate embodiments of the multi-layer material of the invention.

Figures 1 and 2 are partial schematic views of two versions of a multi-layer material 100, 100' produced according to the invention.

Figure 1 shows a multi-layer material 100 produced according to the invention and comprising a first and a second coagulated microfibre cover layer 1, 1" and a support layer 2 made of thermoplastic polymeric material and laminated between the first and second microfibre cover layers 1, 1" in such a way that the support layer 2 is placed between the first and second microfibre cover layers 1, 1". In this way, the first and second microfibre cover layers 1, 1" together form the two opposing visible faces S, S' of the multi-layer material of the invention 100.

The first and second microfibre cover layers 1, 1" and the support layer 2 are laminated together in such a way that the support layer 2 is directly coupled to the first and to the second microfibre cover layers 1, 1" without the use of adhesives, as better described hereinbelow.

Figure 2 shows another embodiment of the multi-layer material 100' according to the invention; parts corresponding to the version of Figure 1 are identified with the same reference numbers and are not described in detail hereinbelow.

The multi-layer material 100' of Figure 2 differs from the version of Figure 1 in that the first cover layer 10 comprises an outer coagulated microfibre cover layer 10' and a reinforcement layer 3 made of non-woven fabric and placed between the support layer 2 and the outer coagulated microfibre cover layer 10', as better clarified hereinbelow.

In the following description, when not explicitly indicated otherwise, the descriptions apply to both embodiments shown in Figures 1 and 2.

The first coagulated microfibre cover layer 1, 10 has a first thickness "d" of between 0.3 mm and 2.1 mm, and in a particularly preferred version between 0.9 and 1.3 mm.

The second coagulated microfibre cover layer 1" has a second thickness d" of between 0.3 mm and 2.1 mm, and in a particularly preferred version between 0.9 and 1.3 mm.

Each coagulated microfibre cover layer 1, 1", 10' is preferably made of a polyamide microfibre coagulated with polyurethane. Preferably, a nylon 6 microfibre is used for each microfibre cover layer 1, 1".

Each coagulated microfibre cover layer 1, 1", 10' comprises about 40-60 wt.% of polyamide and about 40-60 wt.% of polyurethane, preferably about 45-55 wt.% of polyamide and about 45-55 wt.% of polyurethane, and even more preferably about 50 wt.% of polyamide and about 50 wt.% of polyurethane.

It is preferable for the composition of each coagulated microfibre cover layer 1, 1", 10' to be made of about half polyamide and about half polyurethane.

Each coagulated microfibre cover layer 1, 1", 10' is made of non-woven polyamide microfibre fabric coagulated with polyurethane resin.

Each coagulated microfibre cover layer 1, 1", 10' is made by means of a known process in the field, which therefore will not be described in detail but only briefly outlined hereinbelow.

First, bicomponent fibre spinning of polyamide 6, that is fibres of nylon 6, and LDPE (low density polyethylene) is performed with an irregular island structure.

A material is then formed having a matrix consisting of LDPE, the sea component, in which fibres of polyamide 6, the island component, are included. Polyamide 6 fibres have a broad distribution of diameters. Next, the resulting fibres are cut to form short fibres.

Next, the resulting material undergoes needle-punching to make a soft "mattress" of non-woven microfibre fabric.

The microfibre mattress is then subjected to coagulation, a wet process by means of which the microfibre mattress is impregnated with polyurethane and then the polyurethane is made to coagulate on the microfibre mattress made earlier.

A solution of polyurethane in DM F is used for the coagulation, which is then used to impregnate the microfibre mattress. The impregnated material is then passed through water basins so as to extract the DMF and progressively cause the supersaturated polyurethane to deposit onto the fibres of the non-woven fabric.

Subsequently, the LDPE is dissolved from the fibres using a treatment with a toluene solvent, yielding the final desired composition of polyamide and polyurethane.

A microfibre having a polyurethane matrix is obtained in which nylon 6 fibres are embedded.

Alternatively, each coagulated microfibre cover layer 1, 1", 10' is made according to one of the known methods for producing microfibres, for example as described in EP1760189, and then subjected to coagulation with polyurethane resin so as to obtain coagulated microfibre layers 1, 1", 10'.

Although earlier in the description both the first and second microfibre cover layers 1, 1", 10' are considered to have substantially the same composition and properties, according to the invention multi-layer materials having two distinct cover layers 1, 1", 10' with different compositions and also different thicknesses can be produced.

The support layer 2 is made of a mixture of EVA and thermoplastic polyurethane, that is the support layer 2 comprises X% of thermoplastic polyurethane and (100-X)% of EVA.

The hardness of multi-layer material 100, 100' is adjusted by varying the percentages of EVA and thermoplastic polyurethane in the support layer 2. In a version not shown, the support layer 2 is made of EVA.

In another version not shown, the support layer 2 is made of TPU.

The support layer 2 preferably has a hardness from 30 to 80 Shore A, preferably 40-75 Shore A, and even more preferably about 70 Shore A, depending on the EVA and TPU content, and a thickness between 0.2 and 2.0 mm, preferably 0.5-1.5 mm, and even more preferably about 0.7 mm.

In another version not shown, the support layer 2 is made of EVA.

In this case, the support layer 2 preferably has a hardness from 25 to 70 Shore A, preferably 30-50 Shore A, and a thickness between 0.2 and 2.0 mm, preferably 0.3-1.2 mm, and even more preferably about 0.5 mm.

In another version not shown, the support layer 2 is made of expanded thermoplastic polyurethane, TPU, preferably expanded thermoplastic polyurethane with a closed-cell structure.

In this case, the support layer 2 has a hardness between 50 Shore A and 90 Shore A, preferably 60- 70 Shore A.

The support layer 2 has a thickness dl of between 0.2 mm and 2.0 mm, preferably between 0.7 and 1.0 mm.

In other non-illustrated versions of the multi-layer material 100, 100' of the invention, the thermoplastic polyurethane of the support layer is in a non-expanded form or open-cell foam form. The support layer 2 is made by direct extrusion from a mixture of polymeric material, EVA and/or TPU with the possible addition of a blowing agent. This mixture is heated to a temperature from 120 to 200°C and is extruded by a single-screw or twin-screw extruder with a flat head so as to form a film of polymeric material on one of the two microfibre cover layers 1, 1", 10'.

The extrusion temperature is chosen based on the softening point of the mixture of polymeric material; the extrusion temperature must be greater than the softening point of the mixture of polymeric material so as to make a mixture that can easily be applied to one of the two cover layers. Subsequently, the second cover layer is applied so that the support layer is placed between the first and the second cover layers and the resulting material is subjected to lamination by lamination rollers so as to compress the cover layers and stably couple the support layer to the cover layers. Lamination takes place when the mixture of polymeric material reaches a temperature greater than the softening point so as to promote and facilitate adhesion between the support layer and the cover layers.

Advantageously, the lamination step is conducted after about 3-10 s, preferably 6-8 s, after the extrusion of the mixture of polymeric material.

The mixture of polymeric material is extruded directly onto the first layer of coagulated microfibre, and the second layer is laminated after a period of 3-10 s, preferably 6-8 s, so that the cover layers and the support layer are coupled together.

The support layer 2 is made by direct extrusion between the first and the second coagulated microfibre cover layers 1, 1".

As mentioned above, the mixture can be made of EVA, or EVA and TPU, or TPU with the possible addition of a blowing agent to expand the TPU.

If a blowing agent is present, it is preferable for it to be a blowing agent suitable for producing a closed-cell polyurethane foam.

Preferably, the blowing agent is chosen from a group comprising polystyrenes; in other versions the blowing agent is chosen from a group comprising acrylates and/or polyacrylates.

The mixture of thermoplastic polymeric material and the blowing agent, if included, is loaded into an extruder, preferably a flat-head extruder, and extruded at a temperature between 120°C and 200°C. Under these conditions, the blowing agent in the mixture is activated during extrusion, thus causing expansion of the thermoplastic polyurethane.

A layer is then obtained during said extrusion step comprising expanded thermoplastic polyurethane which, by direct extrusion, is laminated directly between the coagulated microfibre cover layers 1, 1", 10'. With reference to the version of Figure 2, as mentioned earlier, the multi-layer material 100' comprises a first cover layer 10 formed by an outer cover layer 10' of coagulated microfibre and a reinforcement layer 3 made of fabric.

The reinforcement layer 3 is glued to the first coagulated microfibre cover layer 10' by suitable adhesives.

The first cover layer 10 is placed in the multi-layer material 100' in such a way that the reinforcement layer 3 is placed between the support layer 2 and the outer coagulated microfibre cover layer 10'. Consequently, in the version of the multi-layer material 100' of the invention shown in Figure 2, the support layer 2 is placed between the first and second cover layers 10, 1" and is applied directly to the second coagulated microfibre cover layer 1".

In a version not shown, the reinforcement layer 3 is at least partially embedded in the support layer 2. This allows the support layer 2 to be coupled directly to the microfibre layer even if the reinforcement layer 3 is present.

The reinforcement fabric layer 3 is made of PA or PL fibres or combinations thereof

The presence of the reinforcement layer 3 makes it possible to obtain a multi-layer material 100' with greater tensile strength.

The reinforcement layer can be a non-woven fabric or also a fabric with an orthogonal structure.

The reinforcement layer 3 is applied to the outer coagulated microfibre cover layer 10' with a suitable adhesive.

In a version of the multi-layer material of the invention that is not shown, both the coagulated microfibre cover layers are provided with a reinforcement fabric layer applied to the corresponding microfibre cover layer and positioned so as to be placed between the coagulated microfibre cover layer and the support layer.

In order to make the multi-layer material 100, 100' of the invention, first the two coagulated microfibre cover layers 1, 1", 10' are made. If present, the reinforcement layer 3 is applied to one of the coagulated microfibre cover layers 10'. Subsequently, the desired mixture of thermoplastic polymeric material is prepared in an extruder, preferably a flat-head extruder.

The mixture can be advantageously made from granules of thermoplastic polymer that are loaded into a hopper which in turn feeds the extruder.

The extruder is preferably a single-screw or twin-screw helical worm extruder.

As mentioned, the mixture may consist of EVA and TPU, or EVA, or TPU, or TPU and a blowing agent. The extruder is then started and extrudes the mixture of thermoplastic polymeric material so as to make a film of thermoplastic polymeric material between the coagulated microfibre cover layers 1, 1", 10. The extrusion step is conducted at a temperature between 120°C and 200°C.

According to the invention, the extrusion step is conducted at a temperature that causes the blowing agent, if any, to decompose and, vice versa, the blowing agent is chosen so as to decompose at the extrusion temperature.

So, the blowing agent decomposes during the extrusion step, generating air at the extrusion temperature and creating bubbles in the thermoplastic polyurethane.

According to the invention, the extrusion step is conducted at a temperature that causes the mixture of thermoplastic material to soften so that a viscous fluid comes out from the extruder head. If a blowing agent is present, this viscous fluid is also in the expanding phase.

The method of the invention can therefore provide a step of heating the mixture of thermoplastic polymeric material and blowing agent in the extruder so as to obtain a viscous fluid that can be applied to a desired substrate.

In this way, a viscous fluid that progressively forms the support layer 2 of the multi-layer material 100, 100' is obtained at the outlet of the extruder head.

If a blowing agent is present, the mixture coming out of the extruder progressively expands so as to gradually form the expanded support layer 2 of the multi-layer material 100, 100'. At least one of the extruder head and the microfibre cover layers 1, 1" is moved in relation to the others so as to generate a relative movement between the extruder head and the microfibre cover layers 1, 1" in order to apply the thermoplastic polyurethane support layer between the microfibre cover layers 1, 1".

In this way, the support layer 2 is applied between the microfibre cover layers 1, 1".

Preferably, the extruder head is moved between the microfibre cover layers.

A viscous fluid that tends to penetrate into the structure of the microfibre cover layers 1, 1" is produced at the outlet of the extruder head.

The EVA and/or TPU partially penetrate into the structure of the microfibre cover layers 1, 1" during extrusion and solidify at the same time. This results in a stable adhesion between the microfibre cover layers 1, 1" and the support layer 2 as it is formed.

This penetration effect is augmented by exerting a certain pressure downstream of the extruder head so as to compress the first and second microfibre cover layers 1, 1" against each other.

In this way, the thermoplastic polymeric material is compressed between the microfibre cover layers 1, 1" and penetrates therein.

This penetration effect is further augmented in the case where the mixture comprises a blowing agent, that is in which the TPU is expanded after extrusion.

This results in a stable adhesion between the microfibre cover layers 1, 1" and the support layer 2 of expanded thermoplastic polyurethane.

This creates a support layer 2 of EVA and/or TPU, possibly expanded or foamed, laminated between the microfibre cover layers 1, 1", that is stably adhered to the coagulated microfibre cover layers 1, 1".

The blowing agent is chosen so as to produce a layer of closed-cell thermoplastic polyurethane foam. If the reinforcement fabric layer 3 is present, the fluid mixture of polymeric material emanating from the extruder bathes the fabric of the reinforcement layer 3 so that the reinforcement layer 3 is substantially embedded in the thermoplastic polymeric material of the support layer 2.

Consequently, as the thermoplastic polymeric material solidifies, it locks the fibres of the reinforcement layer and prevents the multi-layer material of the invention from being prone to fraying phenomena.

At the end of the extrusion step, a multi-layer material 100 is obtained comprising two coagulated microfibre cover layers 1, 1" and one support layer 2 of polymeric material (possibly expanded) which are firmly adhered together, in which the support layer 2 is directly coupled to at least one of the first and second coagulated microfibre cover layers without the use of adhesives.

A particularly stable adhesion is obtained between the coagulated microfibre cover layers 1, 1" and the support layer 2.

Consequently, a particularly stable multi-layer material 100 in which the layers are stably adhered to each other is obtained. This multi-layer material is obtained without using adhesives to glue the coagulated microfibre cover layers and the support layer of expanded thermoplastic polyurethane. The production process for the material of the invention is therefore simpler and more economical than the methods of the prior art.

The multi-layer material of the invention has numerous advantages; the coagulated microfibre cover layers give the support layer strength to withstand sewing and dimensional stability.

Conversely, the support layer of thermoplastic polymeric material provides the material of the invention with greater rigidity and makes it thermoformable.

In addition, the coagulated microfibre cover layers are not prone to snagging and fraying, since they are a non-woven fabric.

The support layer of expanded thermoplastic polyurethane provides the coagulated microfibre cover layers with protection against abrasion, and this feature can be adjusted by the type of polymeric material used, the type of expanded thermoplastic polyurethane used, and the thickness of the support layer. The multi-layer material of the invention can be produced in tape form.

In a version not shown, the multi-layer material of the invention 100, 100' undergoes thermoforming to make a shaped object. A shaped object is understood as an object having a three-dimensional shape, that is in which wall portions of the object are arranged along planes that are mutually transversal.

The multi-layer material is preferably shaped so as to make a three-dimensional object that is concave or is provided with a concave portion defining a housing space.

The three-dimensional object can assume a desired shape depending on the shape of the thermoforming mould used.

The object is configured to keep a desired shape. The object is more rigid in corner portions and/or in regions of curvature variations of the wall portions than in the walls.

In this way an object which is flexible but which can still maintain a desired shape is obtained.

The object has an approximately constant thickness.

Claims

1. Multi-layered material (100) comprising a first and a second cover layer (1, 1") made of coagulated microfibre and at least one support layer (2) made of thermoplastic polymeric material selected from a group comprising EVA, TPU or mixtures thereof, wherein said support layer (2) is arranged between said first and second coagulated microfibre cover layers (1, 1") and is coupled, by means of lamination without using adhesives, to said first and second coagulated microfibre cover layers (1, 1"), wherein said coagulated microfiber said coagulated microfiber cover layers (1, 1") are made of non-woven fabric.

2. Multi-layered material according to the preceding claim, wherein said support layer (2) is made of a mixture containing X% TPU and (100-X)% EVA.

3. Material according to either claim 1 or claim 2, wherein said support layer (2) is produced by means of direct extrusion on said at least one cover layer (1), preferably at an extrusion temperature of between 120°C and 200°C.

4. Material according to the preceding claim, wherein said support layer (2) comprises closed cell thermoplastic polyurethane foam.

5. Material according to any one of the preceding claims, wherein said support layer (2) comprises closed-cell thermoplastic polyurethane foam.

6. Material according to any one of the preceding claims, wherein said support layer (2) is made of expanded thermoplastic polyurethane and has preferably a thickness (dl) of between 0.2 and 2.0 mm, preferably 0.5-1.2 mm, more preferably approximately 0.7-1.0 mm.

7. Material according to the preceding claim, wherein said support layer (2) has a hardness of between 50 and 90 Shore A, preferably 60-70 Shore A.

8. Material according to any one of the preceding claims, wherein said support layer (2) is made of EVA and has a thickness (dl) of between 0.2 and 2.0 mm, preferably 0.3-1.2 mm, more preferably approximately 0.5 mm.

9. Material according to the preceding claim, wherein said support layer (2) has a hardness of between 25 and 70 Shore A, preferably 30-50 Shore A.

10. Material according to the preceding claim, wherein each of said first and second coagulated microfibre cover layers (1, 1") has an additional thickness (d, d") of between 0.2 and 2.0 mm, preferably 0.5-1.2 mm, more preferably approximately 0.7-1.0 mm.

11. Material according to any one of the preceding claims, wherein each of said first and second coagulated microfibre cover layers (1, 1") comprises approximately 40-60 wt.% of polyamide and approximately 40-60 wt.% of polyurethane, preferably approximately 45-55 wt.% of polyamide and approximately 45-55 wt.% of polyurethane, more preferably approximately 50 wt.% of polyamide and approximately 50 wt.% of polyurethane.

12. Material according to any one of the preceding claims, wherein each of said first and second coagulated microfibre cover layers (1, 1") consists of non-woven polyamide microfibre fabric, preferably non-woven polyamide microfibre fabric coagulated with polyurethane.

13. Material according to any one of the preceding claims, wherein each of said first and second coagulated microfibre cover layers (1, 1") consists of non-woven nylon 6 microfibre fabric coagulated with polyurethane.

14. Material according to any one of the preceding claims, wherein each of said first and second coagulated microfibre cover layers (1, 1") consists of non-woven polyamide microfibre fabric, preferably non-woven polyamide microfibre fabric coagulated with polyurethane, and comprising a polyurethane matrix in which the polyamide fibres are embedded.

15. Material according to any one of the preceding claims, wherein said first cover layer (10) comprises an external coagulated microfibre cover layer (10') and a reinforcing layer (3) made of fabric and applied to said external coagulated microfibre cover layer (10') by means of adhesive.

16. Material according to the preceding claim, wherein said reinforcing layer (3) is a fabric having an orthogonal structure and is preferably made of PA or PL fibre.

17. Material according to the preceding claim, wherein said reinforcing layer (3) is a non-woven fabric preferably made of PA or PL fibre.

18. Shaped object having a three-dimensional form and obtained by shaping the multi-layered material according to any one of the preceding claims by means of thermoforming, wherein said object is delimited by wall portions extending along planes that are mutually transversal.

19. Object according to the preceding claim, wherein the wall portions of said object are shaped so as to define at least one concave portion defining a housing space.

20. Object according to claim 18, wherein said object has a concave shape so as to define a housing space.

21. Object according to any one of the preceding claims, wherein said wall portions have a substantially constant thickness.

22. Case comprising an object according to any one of claims 18 to 21.

23. Eyeglass case comprising an object according to any one of claims 18 to 21.

24. Bag or backpack shell comprising an object according to any one of claims 18 to 21.

25. Method for producing a multi-layered material (100, 100'), comprising the following steps: forming at least one first and one second cover layer made of polymeric microfibre material,

impregnating said first and second microfibre cover layers with a polyurethane resin and subjecting said first and said second impregnated microfibre cover layers to coagulation so as to obtain two coagulated microfibre cover layers (1, 1", 10'),

forming a mixture comprising thermoplastic polymeric material, thermoplastic polymeric material of this kind being selected from a group comprising EVA, TPU or mixtures thereof, extruding said mixture on one of said first or said second coagulated microfibre cover layer (1, 1", 10') so as to form a polymeric material film on said first cover layer (1, 1", 10'), said extrusion step being carried out at a temperature of between 120°C and 200°C, - applying said second coagulated microfibre cover layer (1") to said thermoplastic polymeric film so that said film is arranged between said first and second coagulated microfibre cover layers (1, 1", 10'),

laminating said cover layers (1, 1", 10') and said support layer (2) in order to couple said cover layers (1, 1", 10') to said support layer (2) so as to obtain a multi-layered material (100) in which the two visible opposite faces (S, S') consist of the first and the second coagulated microfibre cover layer (1, 1", 10'), respectively, and in which the support layer (2) is coupled, by means of lamination without using adhesives, to said first and second coagulated microfibre cover layers (1, 1", 10').

26. Method according to the preceding claim, wherein said mixture comprises TPU and a blowing agent which causes the expansion of the thermoplastic polyurethane, said blowing agent preferably being an agent that generates closed-cell thermoplastic polyurethane foam, said blowing agent preferably being selected from a group comprising polystyrene.

27. Method according to either claim 25 or claim 26 and further comprising subjecting said multi-layered material (100, 100') to thermoforming processes in order to produce an object having a desired shape, said thermoforming processes preferably being roll or sheet thermoforming processes.

28. Method according to the preceding claim, wherein said thermoforming processes are selected so as to obtain an object having a concave shape or provided with a concave portion defining a housing cavity.

29. Method according to either claim 27 or claim 28, wherein said thermoforming processes are selected so as to obtain an object having walls of a substantially constant thickness.

30. Method according to any one of claims 25 to 29, wherein said lamination is carried out by means of lamination rollers and after a time interval of approximately 3-10 s, preferably 6-8 s after said extrusion step.