ITAR20090016A1 - LASTRIFORM ELEMENT OF NON-WOVEN FABRIC, PARTICULARLY FOR PADDING AND THERMAL AND ACOUSTIC INSULATION, AND ITS REALIZED PROCEDURE - Google Patents

Description

SHEET ELEMENT OF NON-WOVEN FABRIC,

ESPECIALLY FOR PADDING AND THERMAL INSULATION

AND ACOUSTICS, AND ITS REALIZATION PROCEDURE

DESCRIPTION

The present invention relates to a sheet-like element of non-woven fabric, particularly for padding and thermal and acoustic insulation, and its manufacturing process.

In the current state of the art, non-woven fabrics are known, commonly called with their acronym TNT, used in the most disparate fields as padding (especially in the automotive and furniture industry) and as acoustic and thermal insulation in construction, but which find application also in clothing, in filtrations, etc.

This type of TNT is currently produced using vegetable, animal, synthetic and / or mixed fibers with processes that in any case involve the use of synthetic binding fibers.

Normally these fibers have a length of about 65-70 mm and have the characteristic of softening at temperatures of 110-120 ° C: technically they are called bicomponent fibers. The name is due to the fact that these fibers comprise a polyester core (first component) wrapped in another low-melting polymer (second component).

The traditional process for making sheet-like elements of non-woven fabric involves passing the mixed fibers through a carding machine (or carding machine) which arranges the fibers themselves oriented in a direction parallel to each other. In this way, the fibers come out of the machine in the form of a web.

These two-component fiber plies are then transferred to a horizontal (or vertical) lapper which arranges them horizontally (or vertically) with respect to the ground plane. The quantity of plies for the production of TNT is preset according to the desired weight. The plies sandwich thus composed is transferred to a two-belt oven which, with a thermo-cohesive effect on the two-component fibers, binds the TNT according to the programmed thickness and density.

An alternative method of production of sheet-like elements of TNT, provides that the fibers are arranged in a random, unordered way, mixed with the air with the help of a pneumatic card. In this way, by setting the desired thickness and density, they form the desired TNT.

After carding, the fiber sandwich is fed into the thermal bonding machines to weld the bond between the fibers of the TNT.

These sheet-like elements of TNT compete with polyurethane foams, used in the same sectors and for the same applications.

Polyurethane foams have a very serious environmental and ecological impact as they are difficult to recycle and involve high pollution due to the additives and catalysts needed in their production cycle. Furthermore, the foams manufacturing process causes toxic gases to develop and therefore the environment where these products are made are to be considered dangerous for people.

Another disadvantage of foams is that they develop heat at high temperatures, even in the absence of a flame.

Despite these serious problems, polyurethane foam padding and insulation have better mechanical characteristics than non-woven fabric padding and insulation, made with the methods described. In particular, polyurethane foams are far better than non-woven fabrics as regards the resilience test, and therefore find greater use.

Resilience is the measure of the elasticity of the foam: in this test a steel ball is dropped onto the sample to be tested from a certain height and the height reached by the ball is then measured. The result, expressed as a percentage value of the rebound length of the sphere after the impact with the sample surface, is resilience.

Although this test may give a lower value than reality due to the surface failure of the foam sample which tends to brake the sphere laterally, especially in super-soft foams, however, the best polyurethane foams reach a value of 99.4%, which means that materials of this type always substantially return to their initial state, even if subjected to strong compression.

There are products for padding and for the production of thermal and acoustic insulation, of non-woven fabric, capable of competing with polyurethane foams in terms of mechanical characteristics. The realization of TNT padding and insulation of this type involves a particular forming which consists of vertical folding (spreading of several layers of TNT, superimposed on each other and aligned).

However, this process is very laborious and slow, requires expensive machinery and therefore, due to the high production costs, polyurethane foams are still preferred. There are also non-woven padding made of very expensive special fibers which, while guaranteeing excellent results, are nevertheless always not very competitive with respect to foams for economic reasons.

The aim of the invention is to eliminate the aforementioned drawbacks in known types of sheet-like elements of non-woven fabric, particularly for the production of padding and thermal and acoustic insulators, and its manufacturing process, which allows to obtain a product competitive from the point of view of mechanical characteristics, especially as regards resilience, and achieved with an economically competitive process in terms of time and costs.

Within the scope of the above aim, an object of the invention is to provide the sheet-like element of non-woven fabric, particularly for padding and thermal and acoustic insulation, and its manufacturing process, which does not develop toxic gases and which eliminates , or severely limit, environmental pollution.

Another object of the invention is to provide a sheet-like element of non-woven fabric which is recyclable, has a limited environmental impact and which allows easy disposal.

Another object of the invention is to provide a non-woven fabric padding by means of a process that uses traditional raw materials.

Another object of the invention is to provide a sheet-like element of non-woven fabric, particularly for padding and thermal and acoustic insulation, which, unlike polyurethane foams, does not develop heat at high temperatures, even in the absence of flame. Not least object of the invention is to provide a sheet-like element of non-woven fabric, particularly for padding and thermal and acoustic insulators, and its manufacturing process, with means easily available on the market as well as using commonly used materials, so that it is not very cost, competitive to polyurethane foam.

This aim and the other objects are achieved by a sheet-like element in non-woven fabric, particularly for thermal and acoustic padding and insulators, according to the invention, comprising bicomponent fibers, characterized in that it comprises non-silicone-coated fibers constituting, with said bicomponent fibers, a mixture of fibers shaped like balls.

Further characteristics and advantages of the invention will become clearer from the description of a preferred but not exclusive embodiment of the sheet-like element in non-woven fabric, particularly for the production of thermal and acoustic insulators and its manufacturing process.

With reference to the aforementioned figures, the sheet-like element in non-woven fabric, particularly for making thermal and acoustic insulators according to the invention, comprises two-component fibers shaped like balls.

A fundamental characteristic of this sheet-like element is that it comprises non-siliniconised fibers which together with the aforesaid bicomponent fibers constitute a mixture of fibers shaped like balls.

These balls, not necessarily having a substantially spheroidal shape, are normally aggloramerates of fiber, of any material and quality.

Numerous attempts to implement the invention, as well as experiments, have led to the conclusion that, in order to obtain a sheet-like element of non-woven fabric that achieves the aforementioned aim and objects, each non-siliconized fiber of the mixture of fibers must preferably have a maximum length of approximately 40 millimeters.

Preferably, the minimum diameter of each ball of the aforementioned fiber mixture is about 3 millimeters.

Normally, these balls have a maximum diameter of 12-17 millimeters.

Advantageously, the mixture of fibers can be composed, on average, about 80% of non-siliconised fibers.

The non-siliniconized fibers can comprise a blend of fibers of various kinds.

For example, the blend can be composed of non-siliniconised animal and / or vegetable and / or synthetic and / or mineral fibers.

Conveniently, the dosage of each of the non-siliniconized fibers of a different nature will be carried out in an appropriate manner according to the final qualities that the padding must have. Alternatively, it is possible to provide that the non-siliconized fibers comprise only animal fibers, only vegetable fibers or only synthetic fibers. The manufacturing process of the sheet-like element in non-woven fabric, particularly for the production of thermal and acoustic insulators, according to the invention, comprises a succession of steps which consist of: adding non-siliconized fibers to bicomponent fibers to obtain a mixture of fibers; in transforming the mixture of fibers into balls of fibers; in preparing a compact mass of fiber balls; in thermocoating the compact mass of balls in the oven obtaining a block of non-woven fabric; in cutting this block of non-woven fabric so as to obtain a sheet-like element of non-woven fabric.

Advantageously, this process can be carried out continuously.

The addition of non-siliniconized fibers to the two-component fibers, includes the mixing of these two different fibers, in a ratio that we have said to be on average 4 to 1, with the non-siliconized fibers that can be of various kinds (animal and / or vegetable and / or synthetic and / or mining).

The transformation of the mixture of fibers into balls of fibers takes place with a process known per se.

Advantageously, the preparation of the aforementioned compact mass of fiber balls can consist in transferring the balls to a volumetric loader which doses the quantity of balls on a belt.

The quantity of balls discharged is determined by the final pre-set weight for each compact mass to be prepared: the balls are weighed by the belt itself and, by imparting the desired final density, the thickness of each compact mass is determined.

The compact mass is then thermo-bonded and comes out of the thermo-bonding oven like a block of TNT.

At the exit from the thermo-bonding oven, the cutting of the TNT block, to obtain sheet-like elements of non-woven fabric; this cut can be made in a transverse or longitudinal direction with respect to the direction of development of the production chain.

As a first final step of the process, a stacking of the cut non-woven fabric block can be provided.

As an alternative to this first final step, the cut non-woven fabric block may be wound in rolls.

The final product is a sheet-like element of 4 meters with a thickness of 30 centimeters, and a maximum density of over 100 Kg / m <3>.

From what has been described above it can therefore be seen how the invention achieves the intended aim and objects and in particular it is emphasized that a sheet-like element in non-woven fabric is made, particularly for padding and thermal and acoustic insulation, and its manufacturing process, which it allows to obtain a non-woven fabric padding with resilience greater than 99%, therefore comparable to that of the best polyurethane foams, without the use of special fibers or laborious and expensive procedures.

In particular, the realization of the sheet-like element in non-woven fabric, according to the invention, does not require the use of carding machines or lappers and therefore saves the purchase of such very expensive machines that require demanding management and maintenance.

Another advantage of the invention is constituted by the fact that, at the level of raw materials, the animal, vegetable or synthetic fiber has a much lower cost, currently it is about half, compared to that of polyurethane foams.

Furthermore, having foreseen the production of a mixture of fibers using non-siliniconized fibers of various kinds, allows the sheet-like element in non-woven fabric to be used in the most varied industrial sectors.

Another advantage of the invention is given by the fact that, due to its physico-chemical structure, the cut, stacked or rolled non-woven fabric is very compact and with smooth surfaces.

Another advantage of the sheet-like element in non-woven fabric, particularly for the realization of thermal and acoustic insulators and its manufacturing process, consists in the fact that it does not develop heat without flame, even at high temperatures.

Furthermore, the fibers are made of recyclable material and therefore the sheet-like element, according to the invention, has a sustainable environmental impact thanks to the characteristics of the raw material and the production cycle described here.

Another advantage of the invention consists in the fact that, unlike polyurethane foams, this sheet-like element obtained is not water-repellent but is filled with water or other liquid, managing to retain an amount equal to up to 6 times its weight.

Furthermore, by tilting the sheet-like element of non-woven fabric soaked in water or other liquid, with respect to the direction of the ground, it is able to empty itself completely.

Therefore a material of this type could have an important application also in the field of filtration and drainage.

Last but not least, the advantage of the process for manufacturing the sheet-like element in non-woven fabric, according to the invention, consists in the fact that there are no phases with the development of toxic gases, nor are additives and polluting catalysts added and therefore also the process has an ecological cost. very competitive.

In practice it has been found that the device thus described allows the production of a sheet-like element of non-woven fabric, according to the invention, with mechanical characteristics of resilience at least equal to those of polyurethane foams, with a highly competitive process from the point of view economic and environmental impact.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the dimensions, may be any according to the requirements, provided they are consistent with the manufacturing purpose.

Claims (9)

R I V E N D I C A Z I O N I 1) Sheet-like element of non-woven fabric, particularly for padding and thermal and acoustic insulators, comprising two-component fibers shaped like balls, characterized in that it comprises non-silicone-coated fibers constituting, with said two-component fibers, a mixture of fibers shaped like balls. 2) Sheet-like element, according to the preceding claim, characterized in that each of said non-silicone-coated fibers has a maximum length of about 40 millimeters. 3) Sheet-like element, according to one or more of the preceding claims, characterized in that each ball of said mixture of fibers substantially has a minimum diameter of 3 millimeters. 4) Sheet-like element, according to one or more of the preceding claims, characterized in that said mixture of fibers comprises on average about 80% of said non-silicone-coated fibers. 5) Sheet-like element, according to one or more of the preceding claims, characterized in that said non-siliniconized fibers comprise a mixture of fibers of various kinds. 6) Process for the production of a sheet-like element in non-woven fabric, particularly for padding and thermal and acoustic insulators, characterized in that it comprises a succession of phases which consist in adding non-siliconised fibers to bicomponent fibers to obtain a mixture of fibers, in transforming said mixture of fibers into balls of fibers, in preparing a compact mass of balls of fibers, in thermocoating said compact mass in a thermocouple oven obtaining a block of non-woven fabric and in cutting said block of non-woven fabric to obtain said sheet-like element of non-woven fabric. 7) Process according to the preceding claim, characterized by the fact that said preparing a compact mass of fiber balls provides for setting the final weight of each of said compact mass, transferring said fiber balls to a volumetric loader through a sliding belt for dosing the desired quantity of balls, to set the final density of non-woven fabric and to determine the final thickness of each of said compact mass, said sliding belt by weighing said fiber balls. 8) Process according to one or more of the preceding claims, characterized in that it comprises a mixing step of said non-siliconized fibers of various kinds. 9) Process according to one or more of the preceding claims, characterized in that it comprises a continuous production cycle.