COMPOSITE SELF-SUPPORTING PANEL MADE OF NATURAL TEXTILE FIBRES AND RELATIVE MACHINE FOR MAKING IT

Technical field

This invention relates to a composite self-supporting panel made of natural textile fibres.

The invention also relates to a machine for making the composite panel.

In general, textile fibres are divided into two major categories: natural fibres and "technofibres".

Since the object of the invention relates only to the natural fibres described below, a brief summary of the latter is provided.

Natural fibres are divided into fibres of the following origins: vegetable (for example, flax, hemp, jute, coconut, cotton, ...) or animal (for example, silk, and wool of various animals such as sheep, camel ..) or mineral (for example, asbestos, glass, ..) which in some ways are natural, since they derive from minerals found in nature, but which require thermal and/or chemical processes to be obtained.

Background art

Textile fibre panels are used in various technical sectors as well as, of course, in the textile industry; for example, as heat insulating and/or sound-absorbing components; in the building industry, as padding components, in the furniture industry and in the automotive industry, as filtering components for various applications, and in geotechnics. In the textile industry in particular, the fibres are usually woven; in this way, the product acquires consistency and strength.

The secure joining together of the textile fibres in other ways is known.

The most commonly used technology for joining textile fibres is undoubtedly that of traditional weaving.

In addition to this technology, for example, the technology of "non-woven fabric" was conceived in the 1950s; this technology uses "synthetic" fibres (often different and mixed together), is more economical than weaving and allows very high production rates.

There are prior art panels made of textile fibres designed to perform the functions of thermal insulation, acoustic insulation, padding and filtering. However, these textile fibre panels for use in the above-mentioned industries are either made using nonnatural "technofibres" or, if they are natural, they do not have adequate technical characteristics, in particular mechanical strength, to perform the various uses in the industrial sector in an optimised manner.

Aim of the invention

The aim of the invention is to provide composite a self-supporting panel made of natural textile fibres which is able to overcome the drawbacks of the prior art.

A further important aim of the invention is to provide a composite self-supporting panel made of natural textile fibres having a high mechanical strength and with a high level of thermal insulation and/or acoustic insulation and/or padding and/or filtering which does not require high temperature thermal treatments for its production.

A further aim is to provide a composite a self- supporting panel made of natural textile fibres with the function of thermal insulation and/or acoustic insulation and/or padding and/or filtering which can be produced in a manner and in line with the eco-friendly "environmental sustainability" and "circular economy". Yet another aim of the invention is to provide a machine for making a self-supporting panel made of natural textile fibres, which is efficient and inexpensive to make.

These and other aims are achieved by a composite self- supporting panel made of natural textile fibres and relative machine having the technical features described in the appended claims which form an integral part of this description.

Brief description of the drawings

The technical features of the invention and its advantages are apparent from the description which follows to be considered together with the accompanying drawings in which:

- Figure 1 schematically shows a web of textile fibres designed for forming the self-supporting composite panel according to the invention,

- Figure 2 schematically shows the web of Figure 1 after it has been pleated to form the above-mentioned composite self-supporting panel,

- Figure 3 schematically shows the web of Figure 2 after it has been needle punched to form the above- mentioned composite self-supporting panel, - Figure 4 schematically shows a part of an example embodiment of a machine designed for making a composite self-supporting panel of natural textile fibres, and

- Figure 5 schematically shows the needle punching head of the machine of Figure 4 whilst it needle punches a small stretch of a web of textile fibres.

Detailed description

The numeral 1 denotes a composite self-supporting panel made of natural textile fibres according to the invention.

The panel 1 comprises in its composition from 10% to 70% by weight of wool, from 10% to 70% by weight of plant fibres and from 10% to 40% by weight of heat setting material designed to keep joined together said natural textile fibres.

Advantageously, the composition of the panel 1 according to the invention comprises 35% by weight of wool, 35% by weight of plant fibres and the remaining 30% by weight of binder.

Advantageously, moreover, the wool comprises sheep wool.

The structure of the fibre gives the sheep wool softness, elasticity, hygroscopicity, and a high thermal and acoustic insulation capacity.

The plant fibres, on the other hand, comprise hemp or jute fibres.

More in detail, hemp is a natural plant fibre coming directly from the hemp plant.

Amongst its characteristics, it is very resistant to tearing, durable and hygroscopic. Moreover, the cultivation of the hemp plant does not require any chemical substance and treatment against mould or infestation by insects, and the processing cycle from the plant to the fibre has a low environmental impact.

The use of hemp therefore gives the panel 1 a high thermal and acoustic insulation, breathable and hygro- regulation, as well as a high mechanical strength.

Hemp also has antibacterial properties which also translate into a good anti-bacterial nature of the finished panel 1.

In this regard, some recent scientific studies have demonstrated the anti-bacterial capacity of hemp fibre against both positive and negative bacterial strains.

Similar properties can also be attributed to jute fibres.

With regard to the heat setting material, this advantageously comprises recycled polyester.

The heat setting material may generically comprise a bicomponent material advantageously obtained from waste or previous processing residue, such as, for example, recycled polyester bottles.

The use of different fibres to form a panel 1 made of composite material means that it is possible to use the natural characteristics of the various types of fibres (wool and plant fibres), obtaining a panel 1 which, in addition to the above-mentioned high thermal and acoustic insulation properties, with a high breathability and hygroscopicity of the individual fibres (wool and plant fibres such as hemp and jute), also has a synergic effect which translates into a greater resistance to mechanical stresses and a considerable improvement in the inertial thermal capacity for thermal insulation.

These features allow the panel 1 according to the invention to be used as a self-supporting panel for the construction of the thermal covers of buildings or for covering them.

The percentages of wool and plant fibres are also determined as a function of the final use of the panel 1 according to the invention.

If the percentage of wool is greater than that of plant fibres the panel 1 obtained will have less mechanical strength but at the same time it will be more voluminous and more suitable for use inside buildings or for roof/slab coverings since the acoustic and thermal reduction is optimised.

If, on the other hand, the percentage of plant fibres is greater than the percentage of wool the panel 1 will be more resistant and compact.

That is to say, it is more suitable for use outside buildings since the thermal reduction and the ability to shape it is optimised.

A possible embodiment of the panel 1 according to the invention starts from a web of natural textile fibres with the proportions mentioned above which is first "pleated" and then "needle punched" in the direction corresponding to the length of the web; in particular, the needle punching is performed in a direction transversal, preferably perpendicular, to the thickness of the pleated web; in that way, the panel 1 has a certain consistency and structure, but also has a considerable elasticity, softness and lightness.

It should be noted that the term "web" means a series of textile fibres which are not firmly joined together and which is therefore soft, lightweight and also breathable.

Generally speaking, the panel 1 according to the invention comprises a web pleated in the direction of the length and/or width of the panel 1 and needle punched in the direction of the length and/or width of the panel 1.

An example embodiment of a panel 1 according to the invention is shown in Figure 3.

It derives from a web 2 of fibres shown in Figure 1 when it is in a horizontal condition before the processing described below.

The web 2 has been pleated, as shown in Figure 2, in a horizontal direction.

Subsequently, the web 2 is needle punched, as shown in Figure 3, along a horizontal direction.

The needle punching operation, carried out with a limited number of needles (in particular from 1 to 9 per square centimetre), binds the web 2 in a horizontal direction without any additional material, in particular without the use of thread, and compacts the web in a horizontal direction.

As shown in Figures 1 to 3, the needle punching direction corresponds advantageously to the pleating direction, even though this is not strictly necessary for the invention. The panel 1 therefore has a constant thickness S corresponding to the size of the pleating; the pleating size is 20 millimetres, alternatively the pleating size may have a value of between 4 millimetres and 240 millimetres.

Advantageously, the thickness is constant for the entire length of the panel 1 but, it is also possible that, again according to the invention, the panel 1 has variable thickness (derived from a variable pleating size).

In order to reach a thickness S greater than the average length of the fibres (50-110 mm) it is necessary, in order to make the panel 1 resistant, to provide a processing step designed for stabilising the fibres.

This stabilising operation is performed, for example, by adding a heat setting material to the fibres as described above.

In this way, the individual fibres are held together, not only by the needle punching operation but also by the heat setting material spread.

More in detail, during the various processing steps, the web 4 before undergoing the pleating operation is subjected to the heating unit 9 for activating the heat setting material.

The heating unit 9 comprises, for example, a heated and heat-adjustable cylinder (therefore adjustable at different temperatures to be chosen by the user as a function of the material of the panel 1).

The web 4 passes into contact with the cylinder in such a way as to activate the heat setting material. In this way, the web 4 is much more robust and immune from any tears even with very high thicknesses and greater than the length of the fibres.

Figures 4 and 5 also show an example of a machine designed for making a panel 1 according to the invention.

A description is given below, with the aid of Figures 4 and 5, of only the part of the machine which performs the most innovative operations, the remaining processing is therefore performed in a traditional manner.

Figure 4 shows:

- means 3 designed to continuously feed a long web 4 of textile fibres towards a processing zone 5,

- a pleating head 6 positioned in said processing zone 5 and designed to repeatedly perform pleating operations on the web 4,

- a needle punching head 7 located in said processing zone 5 and designed to perform repeatedly needle punching operations on the web 4 after it has been pleated, and

- means 8 for continuously feeding the web 4 after it has been pleated and needle punched away from the processing zone 5.

As mentioned, the machine described above also comprises a heating unit 9, designed for the thermal fusion of the heat setting material, which advantageously comprises a heated and heat-adjustable cylinder.

Advantageously, the heating unit 9 is positioned before the pleating head 6 and of the needle punching head 7. In Figure 4, the web 4 is continuous, extends longitudinally from left to right, and moves progressively from left to right, passing through the processing zone 5, whilst working.

As mentioned, methods and apparatuses for producing fibre webs are known and already in use; they are therefore not described here.

After the processing shown schematically in Figure 4, the pleated and needle punched web 4 may be, for example, cut to form the panel 1 according to the invention.

The means 3 and 8 may be formed, for example, by conveyor belts.

The pleating head 6 is schematically illustrated, in Figure 4, like a straight bar designed to fold the web 4.

The needle punching head 7 is schematically illustrated, in Figures 4 and 5, as a rectilinear bar 71 equipped with a plurality of needles 72 of length such as to pass through a plurality of layers of web 4. Many details regarding the needle punching are not provided here because said technique is of per se known type and used in the non-woven fabric sector; it should be noted that, according to the invention, the material to be needle punched is not squeezed between plates as occurs in the case of non-woven fabrics.

According to the example embodiment of Figure 4, the conveyor belt 3 feeds the web 4 longitudinally towards the processing zone 5 from left to right; the processing zone 5 is lower (for example, 5-20 cm lower) than the feed zone of the web 4 defined by the conveyor belt 3.

According to the embodiment of Figure 4, the pleating head 6 moving first from the top downwards from a predetermined upper position to a predetermined lower position and then from the bottom upwards from the predetermined lower position to the predetermined upper position first creates a fold of the web 4 downwards and then a fold of the web upwards; in that way, a pleating operation is performed on the web 4 along a direction corresponding to the length of the web itself (that is to say, the folds are transversal to the length of the web).

According to the example embodiment of Figure 4, the needle punching head 7 moving first from left to right from a predetermined position far from the web (Figure 4) to a predetermined position adjacent to the web (Figure 5) and then from right to left from the predetermined position adjacent to the web to the predetermined position far from the web, performing a needle punching operation on the pleated web along a direction corresponding to the length of the web.

According to the example embodiment of Figure 4, the conveyor belt 8 feeds the web 4 from left to right continuously after it has been pleated and needle punched, moving it away from the processing zone 5. Precise directions and arrangements which, in effect, are the most typical and advantageous for implementing the invention, have been clearly indicated in the previous paragraphs, even though they are not necessarily the only possible ones. As may be inferred from Figure 4, the pleating and needle punching operations are repeated; in particular, the pleating operations are alternated with the needle punching operations; more specifically and advantageously, each pleating operation immediately follows a needle punching operation.

According to the example embodiment of Figure 4, the pleating head 6 performs an alternating translational movement in a direction perpendicular to the web 4, the needle punching head 7 performs an alternating translational movement in a direction longitudinal to the web 4 as it moves (direction DI) in the machine towards the processing zone and to that of the finished panel 1 as it moves in the machine away from the processing zone (to be precise, the head 7 with its needles 72 works on the web 4 in a direction perpendicular to the web 4, but after the web 4 has been pleated, that is to say, folded several times); specifically, the needle punching head 7 is shaped and moves in such a way as to complete previous pleating operations, that is to say, when the bar 71 of the head 7 moves towards the predetermined position adjacent to the web (Figure 5), it presses it a little, and marks the folds of the pleating.

According to the example embodiment of Figures 4 and 5, the needle punching head 7 comprises a plurality of needle 72 with a preferred density of needles per square centimetre ranging from 1 to 9 and with a preferred length ranging from 4 to 8 centimetres. Another embodiment of the panel 1 according to the invention does not comprise the pleating operations. The choice of whether or not to perform the pleating is determined by the desired final application of the panel 1. The invention achieves important advantages by overcoming the drawbacks of the prior art. A first important advantage consists in the fact that a composite self-supporting panel made of natural textile fibres according to the invention has a high mechanical strength and a high level of thermal insulation and/or acoustic insulation and/or padding and/or filtering without requiring the performance of high temperature heat treatments.

A further advantage of the invention is that the composite self-supporting panel made of natural textile fibres with the function of thermal insulation and/or acoustic insulation and/or padding and/or filtering is made in a sustainable and environmental-compatible manner.