IT201800009427A1 - MULTILAYER COMPOSITE MATERIAL AND RELATED PRODUCTION PROCESS - Google Patents

Description

Description of the invention having as title:

"MULTILAYER COMPOSITE MATERIAL AND RELATED MANUFACTURING PROCESS"

FIELD OF APPLICATION

The present invention relates to a multilayer composite material, consisting of at least one woody layer associated, by means of an adhesive material, with at least one support layer composed of glass fibers, carbon fibers, aramid fibers or the like. The present invention also relates to the process for making the multilayer composite material.

By way of non-limiting example only, the multilayer composite material, according to the present invention, can be used to make semi-finished products, for example, for the coating of skis, snowboards, or the like. Furthermore, given its excellent mechanical properties, the aforementioned multilayer composite material can be used directly as a final product to create, for example, furnishing elements such as chairs, tables or other.

STATE OF THE TECHNIQUE

It is known that in the production of objects such as chairs, tables or other, wood-based multilayer materials can be used, made by gluing a plurality of sheets of wood to each other.

Wood sheets are generally obtained by cutting easily workable trees such as birch, poplar, beech, ash or other trees with similar properties. Typically, the wood sheets have a constant thickness between about 0.8 mm and about 3.5 mm and, when used individually, have poor mechanical properties.

Generally, a multilayer material is formed by at least two sheets of wood glued together to obtain a material thickness varying between about 8 mm and about 30 mm.

The sheets of wood are superimposed on each other, alternating layers of glue material, and are then pressed into a special shaped mold to give the desired final shape.

One of the drawbacks in the use of known multilayer materials to make furnishing objects is that to obtain adequate mechanical properties, a thickness of material is required which depends on the type of application, but in any case variable between about 8 mm and about 30 mm. In other words, to date, it is difficult to produce a wood-based multilayer composite material, of reduced thickness and suitable for different applications, which may also require high mechanical strength, for example resistance to bending.

A further drawback resides in the fact that it is not possible to directly produce an object with a variable section, for example in the areas used for the insertion of connection means, which, as is known, require a certain thickness, for example a greater thickness, in the area where they are to be inserted into the material.

To partially obviate this drawback, an increased thickness of the entire profile of the object to be made is usually achieved with a consequent increase in the costs of raw material, or means of connection external to, or only partially inserted into, the material are used. These external means of connection can, however, make the object unsightly and therefore of little profitable value.

This problem is also encountered in the production of skis and snowboards, for example in the area of the ski / snowboard where the connection means for the boots must be placed.

There is therefore a need to improve a multilayer material which can overcome at least one of the drawbacks of known multilayer materials.

An object of the present invention is to provide a multilayer composite material which, having the same mechanical characteristics, has a lower thickness than a known multilayer material. In this way it is possible to reduce the amount of wood sheets to be used. It is also possible to obtain objects with a much lower thickness.

A further object of the present invention is to provide a multilayer composite material which maintains the typical aesthetic qualities of wood, such as texture, grain, grain, anomalies and defects, but which has superior mechanical characteristics. In this way it is possible to create a material that has the same appearance as wood, but, for example, greater resistance to biological alterations and greater dimensional stability with respect to variations in humidity.

Another object of the present invention is to provide a multilayer composite material which maintains the aesthetic qualities typical of wood, but which is extremely elastic and almost impossible to break.

It is also an object of the present invention to provide a very thin multilayer composite material, which is easy to smooth and can be applied to the surface of an object in order to ennoble it. In this way, you avoid directly smoothing the surface of the object, which may have convexity or concavity, saving time and reducing production costs.

In order to obviate the drawbacks of the known art and to obtain these and further objects and advantages, the Applicant has studied, tested and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the independent claims. The dependent claims disclose other features of the present invention or variants of the main solution idea.

Embodiments described herein refer to a multilayer composite material.

The multilayer composite material is defined by at least one support layer, comprising intertwined fibers, and at least one woody layer, comprising at least one wood sheet; the at least one support layer and the at least one woody layer are joined together permanently by means of an adhesive material.

According to an aspect of the present invention, the woody layer and the support layer are embedded in the glue material, so that this glue material is permeated and diffused in this woody layer and in this support layer.

Advantageously, by means of this diffusion and permeation of the gluing material, the final multilayer composite material according to the invention has the appearance and aesthetic qualities of the wooden material layer, but also has a high mechanical resistance, which makes it usable for various applications, for example for the lining of skis, snowboards, or other. In addition, given the aforementioned mechanical properties and also of aesthetic value, the aforementioned multilayer composite material can be used directly as a final product to create, for example, furnishing elements such as chairs, tables or other.

In possible configurations and choices of woody and support layers, it is possible to obtain a highly elastic and hardly breakable material, suitable for example for the creation of design objects that combine functionality with aesthetic characteristics and a refinement of shapes that traditional composite materials do not always I can guarantee.

The present invention also relates to a process for manufacturing the multilayer composite material described above. The procedure involves:

- dosing an adhesive material to select the correct amount of adhesive material to be used in relation to the surface of at least one support layer and at least one woody layer defining the material; - apply the adhesive material on the support layer and / or on the woody layer;

- place the support layer and the wood layer impregnated with adhesive material one on top of the other;

- apply a variable pressure between about 1 bar and about 5 bar, preferably between about 2 bar and about 4 bar and a variable temperature between about 40 to the support layer and to the wood layer, positioned one on top of the other and impregnated with glue material ° C and about 100 ° C, preferably between 60 ° C and 80 ° C;

- cool the material.

The various aspects and features described in the present disclosure can be applied individually where possible. These individual aspects, for example aspects and characteristics present in the description or in the attached dependent claims, can be the subject of divisional questions.

It should be noted that any aspect or characteristic that is found to be already known during the patenting procedure is intended not to be claimed and to be the subject of a disclaimer.

ILLUSTRATION OF DRAWINGS

These and other characteristics of the present invention will become clear from the following description of embodiments, provided by way of non-limiting example, with reference to the attached drawings in which: - fig. 1 is a schematic sectional view of a basic embodiment of the multilayer composite material according to the present invention; - fig. 2 is a schematic sectional view of a further embodiment of the material according to the invention;

- fig. 3 is a schematic sectional view of a further embodiment of the material;

- fig. 4 is a schematic sectional view of a variant of fig. 3, which provides a central woody layer of variable section to allow the insertion of an insert;

- fig. 5 is an explanatory exploded view of the material of fig. 2 in which the adhesive material is visible;

- fig. 6 is a view of the material of fig. 2 in which the adhesive material is permeated and diffused in the various layers of the present multilayer composite material;

- fig. 7 is an axonometric view of a possible object made directly with the material according to the invention.

To facilitate understanding, identical reference numbers have been used wherever possible to identify identical common elements in the figures. It should be understood that elements and features of one embodiment can be conveniently incorporated into other embodiments without further specification.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the various embodiments of the invention, of which one or more examples are illustrated in the attached figures. Each example is provided by way of illustration of the invention and is not intended as a limitation thereof. For example, the features illustrated or described as being part of an embodiment may be adopted on, or in association with, other embodiments to produce a further embodiment. It is understood that the present invention will include these modifications and variations.

With reference to the attached figures, a multilayer composite material in accordance with the present invention is indicated as a whole with the reference number 10.

In accordance with embodiments, the material 10 is defined by at least one support layer S, comprising intertwined fibers, and at least one woody layer W, comprising at least one wood sheet.

In accordance with embodiments of the present invention, the support layer S can be defined by one or more planes of superimposed fibers having different inclination angles of the interlacing of the fibers. The at least one support layer S and the at least one woody layer W are permanently joined together by means of an adhesive material G, see for example fig. 5.

According to an aspect of the present invention, the woody layer W and the support layer S are embedded in the glue material G, so that the glue material G is permeated and uniformly diffused in the woody layer W and in the support layer S.

In the embodiment of fig. 1 the material 10 according to the present invention is defined by a W-S structure.

In particular, as a result of a pressure and a temperature exerted on the woody layer W and on the support layer S, as will be described below, the glue material G can permeate through pores of the woody layer W and between the fibers of the support layer. S to permanently join the wood layer W with the support layer S.

The woody layer W is the outermost layer of the material 10, so as to make the latter similar to the sheet of wood that constitutes the woody layer W. The material 10, in particular, remains aesthetically similar to the wood constituting the woody layer W.

The woody layer W consists of a woody material in the form of sheets of wood, obtained from the tangential cut of tree trunks.

The woody layer W has, by its nature, pores in number and dimensions characteristic of the type of wood that constitutes the woody layer W.

According to possible embodiments, the woody layer W can be selected from a group comprising sheets of ash, beech, birch, poplar wood. Preferably, the woody layer W consists of a sheet of ash wood, because this type of wood has an ideal porosity coefficient for making the material 10.

In fact, an excessively low porosity coefficient, i.e. an excessively compact wood, prevents the glue material G from crossing the woody layer W, substantially decreasing the surface involved in gluing, since the presence of pores increases the overall surface involved in gluing. allowing the permeation of the woody layer W.

In accordance with an aspect of the present invention, the woody layer W can have a thickness of between about 0.5 mm and about 2 mm, preferably between 0.8 mm and 1.5 mm.

Excessive thicknesses of the woody layer W do not, in fact, allow the glue material G to permeate the woody layer W. In particular, the glue material G, impregnating the woody layer W, gives a characteristic appearance to the material 10, coloring the color of the glue material G, the texture, fiber, grain, anomalies and defects of the wood layer W.

According to embodiment variants, if the material 10 is defined by more than one woody layer W, the woody layers W which form the material 10 can also be different from each other or be wood sheets obtained from different trees. Furthermore, the woody layers W which constitute the material 10 can have the same thickness, that is, they can have a different thickness from each other.

According to embodiments illustrated, the thickness of the wood layer W can be constant, see figs. 1-3, that is, it can advantageously have areas in which it is greater or less than the prevailing thickness of the woody layer W. For example, as illustrated in fig. 4, the woody layer W, central to the support layers S, has a variable thickness, in a localized zone Z, to facilitate Γ insertion of a connecting means 11.

According to possible embodiments, illustrated in fig. 3, if the structure of the material is W-S-W-S-W, the central woody layer W, i.e. the woody layer W between the support layers S, can be advantageously replaced with an intermediate layer of material different from the material of the woody layer W, to make a W-S-Y-S-W structure. In particular, the intermediate layer can be selected from a group comprising rubber, metal, foam, felt or other similar or similar materials. For example, if the intermediate layer is made of rubber, it is possible to obtain a rigid and compact material 10 at least externally, which has further characteristics for example of damping, thermal and acoustic insulation conferred by the rubber.

In accordance with an aspect of the present invention, the support layer S consists of a plurality of fibers woven according to a weft-warp configuration and arranged in a plane to form a continuous layer.

According to possible embodiments, the support layer S can be made with a continuous and parallel arrangement of the fibers, or it can be made by superimposing a plurality of fibers cut and arranged in a plane with random orientation.

Typically, the support layer S can be defined by one or more superimposed fiber planes having different inclination angles of the intertwining of the fibers, so as to guarantee the desired mechanical properties in the directions of action of the stresses acting on the object constituted. from material 10.

According to possible embodiments, the support layer S can comprise fibers selected from a group comprising at least one of carbon, glass, aramid fibers or a combination of the above. In particular, the aforementioned fibers have excellent properties of mechanical strength and elastic modulus, and the angle of inclination of the fibers of the support layer S determines the characteristics of bending and torsion, as well as the stiffness of the material 10.

In accordance with an aspect of the present invention, the support layer S can have a density ranging from about 40 g / m <2> to about 1500 g / m <2> and more.

According to possible embodiments, the support layer S can have a thickness varying between about 0.2 mm and about 2 mm, preferably between 0.3 mm and 1.5 mm.

The aforementioned density and thickness values refer to the support layer S before being used to make the material 10.

According to possible embodiments, the support layers S which form the material 10 can also be different from each other or be constituted by different fibers, or by different inclination angles of the fibers.

According to possible embodiments, the support layers S which constitute the material 10 can have the same thickness, that is, they can have a different thickness from each other.

By way of non-limiting example, the support layer S can be composed of five layers of intertwined fibers respectively with an inclination angle of 0 °, 0 °, 45 °, 90 °, -45 °. However, the choice of the support layer S varies in consideration of the type of application for which the material 10 will be used.

Advantageously, the material constituting the support layer S is stored in rolled sheets of about 50 or more meters and, if necessary, is unrolled, cut and shaped. It should be noted that the material constituting the support layer S can be available on the market in different formats, for example in sheets of various sizes.

In accordance with an aspect of the present invention, the gluing material G is configured to permanently join the wood layers W with the support layers S and possibly with further intermediate layers.

According to possible embodiments, the gluing material G can be a thermosetting resin selected from a group comprising polyester resin, epoxy resin, phenolic resin, silicone resin or other similar or assimilable resins.

In accordance with an aspect of the present invention, the gluing material G consists of a mixture of an epoxy resin and a cross-linking resin.

In particular, the gluing material G consists of a mixture of epoxy resin based on Araldite® and a cross-linking polyamide resin based on Aradur®. The cross-linking resin is added to the Araldite®-based epoxy resin in the preparation phase of the adhesive material G.

According to possible embodiments, the gluing material G can comprise a thickening substance suitable for increasing the structural strength of the gluing material G. This thickening substance can be defined by microspheres.

Typically, the gluing material G can have black or gray color or a combination of these.

According to possible embodiments, a pigment can be added to the gluing material G during the preparation step to aesthetically characterize the material 10. For example, the pigment can have a blue, red, green color.

The adhesive material G can be applied on the surface of the support layer S or the wood layer W, or on both surfaces of the support layer S and the wood layer W which are to be joined. Preferably, the gluing material G is applied to both surfaces of the support layer S and of the wood layer W which are to be joined.

In accordance with an aspect of the present invention, the amount of gluing material G applied on the surface of the support layer S and on the surface of the woody layer W varies between about 30 g / m <2> to about 500 g / m. The Applicant has experienced that the amount of gluing material G for making the material 10 according to the present invention can vary between about 100 g / m <2> and about 1500 g / m <2>.

According to embodiments, the gluing material G can be variable between about 300 g / m <2> and about 800 g / m <2>.

With the aforementioned ideal quantity of glue material G, a perfect union is obtained between the wood layers W and the support layers S, avoiding waste of glue material G.

As mentioned above, in a basic embodiment, with reference to FIG. 1, the structure of the material 10 is of the W-S type, and the material 10 can be glued to an object in order to cover it. Preferably the material 10 is glued, on the object to be coated, from the side of the support layer S, so that the externally visible layer is the woody layer W.

In a further preferred embodiment, with reference to fig. 2, the material 10 comprises the support layer S interposed between two woody layers W to form a structure W-S-W. In this case, the material 10 can be glued to an object in order to coat it.

In a possible embodiment, illustrated in fig. 7, the material 10 according to the present invention can be used to directly make an object 12, in this case a stool. In this case, the material 10 can have a W-S-W-S-W structure to give the object 12 greater stiffness.

According to possible embodiment variants, the material 10 can be defined by more than three support layers S interposed with four or more woody layers W, as just described for the example of fig. 7, and the present invention can be adopted, with the usual adaptations of an expert in the field, also for the production of these types of materials 10.

The present invention also refers to the method for making the material 10 described above.

The process for making the material 10, in accordance with the present invention, provides for:

- dosing an adhesive material G to select the correct amount of adhesive material G to be used in relation to the surface of at least one support layer S and of at least one woody layer W defining the material 10;

- apply the adhesive material G on the support layer S and / or on the woody layer W;

- place the support layer S and the woody layer W on top of each other impregnated with glue material G;

- apply to the support layer S and the wood layer W, positioned one on top of the other and impregnated with glue material G, a variable pressure between about 1 bar and about 5 bar, preferably between about 2 bar and about 4 bar and a variable temperature between about 40 ° C and about 100 ° C, preferably between 60 ° C and 80 ° C;

- cool the material 10.

The process can be carried out manually, or automatically with machinery known to an expert in the field. In particular, the application of the glue material G can be carried out by spraying, with a special roller machine or manually, using a spatula.

In accordance with an aspect of the present invention, the application of pressure and temperature can have a duration ranging from about 40 minutes to about 80 minutes, preferably between about 50 minutes and about 70 minutes.

The cooling of the material 10 occurs in a natural way, ie avoiding forced cooling phenomena. This allows the elasticity characteristics of the material 10 to be maintained, preventing it from assuming a brittle / glassy behavior.

Subsequently, the material 10 is smoothed to even out the surface of the woody layer W, to eliminate the asperities produced by the glue material G leaking from the woody layer W due to the application of pressure.

Experimental tests

The Applicant has subjected the multilayer composite material object of the present invention to bending tests obtaining the following results.

In a first test, a sample of known material was tested, defined by a woody layer W in oak wood having a width of 25 mm, a length of 25 mm and a thickness of 1 mm. This layer has not been subjected to a process according to the present invention and is used as a comparison example with respect to the samples of the present invention. From the tests carried out, an average longitudinal bending strength of about 114.6 MPa and an average transverse bending strength of about 2.36 MPa are obtained.

In a second test, the sample of material used is a multilayer composite material in accordance with the present invention with structure W-S-W or two wooden layers W and a support layer S, having a width of 25 mm, a length of 25 mm and a thickness equal to 1 mm. An average longitudinal bending strength of about 189.2 MPa and an average transverse bending strength of about 54.3 MPa are obtained.

In a third test, the sample of material used is a multilayer composite material in accordance with the present invention with structure W-S-W-S-W, i.e. three woody layers W and two support layers S, having a width of 25 mm, a length of 25 mm and a thickness equal to 1.5 mm. An average longitudinal bending strength of about 313.6 MPa and an average transverse bending strength of about 245.23 MPa are obtained.

It is clear that modifications and / or additions of parts may be made to the multilayer composite material and related manufacturing process described up to now, without thereby departing from the scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person skilled in the art will certainly be able to realize many other equivalent forms of a multilayer composite material and the related manufacturing process, having the characteristics expressed in the claims and therefore all falling within the scope of protection defined by them.

In the following claims, the references in brackets are for the sole purpose of facilitating reading and should not be considered as limiting factors as regards the scope of protection underlying the specific claims.

Claims (10)

CLAIMS 1. Multilayer composite material defined by at least one support layer (S), comprising intertwined fibers, and at least one woody layer (W), comprising at least one sheet of wood, being said at least one support layer (S) and said at least one woody layer (W) joined together permanently by means of an adhesive material (G), characterized in that said woody layer (W) and said support layer (S) are embedded in said adhesive material (G), and so that said gluing material (G) is permeated and uniformly diffused in said woody layer (W) and in said support layer (S). 2. Material as in claim 1, characterized in that said woody layer (W) has a thickness comprised between about 0.5 mm and about 2 mm, preferably between 0.8 mm and 1.5 mm. 3. Material as in claim 1, characterized in that said support layer (S) has a thickness varying between about 0.2 mm and about 2 mm, preferably between 0.3 mm and 1.5 mm. 4. Material as in claim 1, characterized in that said support layer (S) has a density ranging from about 40 g / m to about 1500 g / m <2>. 5. Material as in claim 1, characterized in that said support layer (S) comprises fibers selected from a group comprising at least one of carbon, glass, aramid fibers or a combination of the above. 6. Material as in claim 1, characterized in that said gluing material (G) consists of a mixture of an epoxy resin and a cross-linking resin. 7. Material as in claim 5, characterized in that a pigment is added to said gluing material (G) during the preparation step to aesthetically characterize the material (10). 8. Process of making the material as in any one of claims 1 to 7, said process comprising: - dosing an adhesive material (G) to select the correct quantity of adhesive material (G) to be used in relation to the surface of at least one support layer (S) and of at least one woody layer (W) defining the material (10); - applying said adhesive material (G) on said support layer (S) and / or on said woody layer (W); - place said support layer (S) and said wooden layer (W) on top of each other impregnated with said glue material (G); - apply to said support layer (S) and to said wooden layer (W), positioned one on top of the other and impregnated with said adhesive material (G), a variable pressure between about 1 bar and about 5 bar, preferably between about 2 bar and about 4 bar and a variable temperature between about 40 ° C and about 100 ° C, preferably between 60 ° C and 80 ° C; - cool the material (10). 9. Process as in claim 8, characterized by the fact that the application of pressure and temperature has a duration varying between about 40 minutes and about 80 minutes, preferably between about 50 minutes and about 70 minutes. 10. Process as in claim 8, characterized in that the cooling of the material occurs in a natural way, ie avoiding forced cooling phenomena.