PROCESS FOR MAKING A THREAD COMPRISING A MIXTURE OF NATURAL AND/OR ARTIFICIAL AND/OR SYNTHETIC AND/OR MINERAL FIBRES, EITHER PURE OR MIXED WITH EACH OTHER, PROCESS FOR MAKING A FABRIC BY SAID THREAD.

Description of a patent for invention in the name of:

1) GHERTEX S.R.L- 20020 Cesate (Mi) 2) G.T.I. SPA - GRUPPO TESSILE INDUSTRIALE - 13871 Verrone (Bl)

The present invention relates to a process for making a thread comprising a mixture of natural and/or artificial and/or synthetic and/or mineral fibres, either pure or mixed with each other, to a process for making a fabric by said thread, to a thread and to a fabric thus made.

In particular, the present finding relates to fabrics made of vicuna, cashmere, alpaca, silk, wool and fibres in general, natural and/or artificial and/or synthetic and/or mineral, either pure or mixed with each other, which due to the limited sizes thereof (i.e., they are very thin fibres that have a very high mass density in tex) cannot be woven or during the weaving, tend to break up.

By fabric it is meant both the fabric made with a shuttle machine and the fabric made with a knitting machine, either circular or rectilinear.

As is known, when fabrics are to be made using very thin fibres (for example one of the indicated fibres), the fibres are alternately woven alone, or together with soluble fibres.

In the first case, very thin fabrics are made; however, such processes have very high costs since the fibres have a poor resistance and are difficult to weave.

In the second case, a thread consisting of the desired fibre twisted with a soluble thread is used.

The twisted thread is woven making a fabric that is immersed in a solution suitable for dissolving the soluble fibres so as to obtain the fabric made of the desired fine fibre only.

However, the traditional process methods exhibit some drawbacks that may be found in the high production costs and in the large waste (due to the poor resistance of the fibres to be woven that break up during the process).

Moreover, in the traditional process it is possible to make fabrics that are less soft and bulky than those obtained according to the invention; in other words, since very fine vicuna, cashmere, alpaca, silk, wool or other fibres are typically used for making fabrics, clothing items and textile accessories for high market segments, the manufacturers are trying to make fabrics which should be increasingly lighter, softer and bulky, since these features are felt as a synonym of quality of the raw material and of the end product.

The technical task of the present invention therefore is to provide a process for making a thread comprising a mixture of natural and/or artificial and/or synthetic and/or mineral fibres, either pure or mixed with each other, a process for making a fabric by said thread, a thread and a fabric that will allow eliminating the technical drawbacks of the prior art.

Within the scope of this technical task, an object of the invention is to make a thread, a process for making a thread and a process for making a fabric which should allow making a very light, soft and bulky fabric.

Another object of the invention is to make a fabric which should be less expensive than the corresponding traditional fabrics, easy to process, resistant and with limited production waste.

The technical task, as well as these and other objects, according to the present invention, are achieved by implementing a process for making a thread comprising a mixture of natural and/or artificial and/or synthetic and/or mineral fibres, either

pure or mixed with each other, a process for making a fabric by said thread, a thread and to a fabric thus made according to the annexed claims.

In a particular embodiment, the process according to the invention may be used for making a thread comprising a mixture of natural and/or artificial and/or synthetic and/or mineral fibres through a spinning cycle among the following ones:

carded spinning, combed spinning, "compact", "open end", where "compact" spinning indicates the process with fibre compacting during the spinning through pneumatic depression as described for example in document US6134872.

In a particular embodiment, the second fibres consist of PVA fibres.

In a particular embodiment, the fabric is immersed in a cold water bath, where the ratio between fabric weight and bath weight is less than 1 :25 and preferably equal to about 1 :30.

In a particular embodiment, the above water bath is added with acetic acid until a PH equal to about PH 5.5 is obtained. In a particular embodiment, once the fabric has been immersed in said cold water bath, the water is heated to a temperature that takes a value within the range 65-90 ⁰ C. In a particular embodiment, once the water bath with the fabric has been heated to a temperature between 65-90 ⁰ C, the fabric is left to spin into the bath for a time comprised between 25-50 minutes.

In a particular embodiment, once the fabric has been left to spin in the heated bath, the bath is cooled with the input of cold water and drained.

In a particular embodiment, once the bath has been cooled and drained, the fabric is washed with purified water having a temperature of about 40 ⁰ C, preferably for a time of about 10 minutes.

In a particular embodiment, once the fabric has been washed with purified water

having a temperature of about 40 ⁰ C, the bath is drained, then other washing baths are carried out with cold purified water.

Further features and advantages of the invention will appear more clearly from the description of a preferred but non-exclusive embodiment of the process for making a thread, of the process for making a fabric, of the thread and of the fabric thus made according to the finding, illustrated by way of a non-limiting example in the annexed drawings, wherein:

figure 1 shows a section of a thread according to the finding comprising first and second fibres; and

figure 2 shows a section of the thread of figure 1 wherein the second fibres have been dissolved.

The process for making a thread comprising a mixture of natural and/or artificial and/or synthetic and/or mineral fibres, either pure or mixed with each other, consists in humidifying the first fibres evenly; such first fibres for example are natural fibres such as vicuna, cashmere, alpaca, silk, wool fibres and/or artificial fibres such as viscose fibres and/or synthetic fibres and/or mineral fibres such as glass fibres, carbon fibres, asbestos fibres, aramidic fibres, kevlar, either pure or mixed with each other, which are combined in a sliver.

The first fibres that have been humidified are then mixed with second fibres that are soluble in an environment wherein the first fibres are not soluble, thus making a sliver consisting of a mixture of first and second fibres.

The soluble fibres for example consist of water soluble fibres such as alginate or polyvinyl alcohol (PVA) fibres that are soluble in aqueous solution, or fibres soluble in carbonizing (an aqueous solution of sulphuric acid) such as cellulosic fibres (vegetal and/or artificial fibres); such soluble fibres are comprised in the sliver by a percentage by weight below 80% and preferably comprised between 30-60%.

Afterwards, the sliver is spun with an S or Z twist, making a thread consisting of a mixture of first and second fibres.

Figure 1 shows a thread produced in this way; in this figure, reference numeral 1 indicates the thread as a whole, reference numeral 2 the first fibres and reference numeral 3 the second fibres (the soluble ones).

The humidification of the first fibres takes place by inserting such first fibres in a wet chamber, so that the first fibres may absorb all the humidity they are capable of absorbing.

The wet chamber has humidity not below 90% and the first fibres are kept in the wet chamber up to three days and preferably for about two days.

This allows obtaining the first fibres evenly humidified. When extracted from the wet chamber, the first fibres are subject to an enzymic action for reducing the electrostatic charges of the fibres and facilitating the reciprocal smoothness thereof.

The enzymic bath consists by 75% water, 15% antistatic, 10% oil; it is made in multiple passages, at each passage yielding a limited enzymic oil rate to the first fibres.

After the treatment, about 2% oil and 2, 3% antistatic of the quantity respectively of oil and antistatic sprayed remains on the fibres.

After the enzymic bath, the first fibres are left to stand on reels up to three days and preferably, for about one or two days, so as to keep them compact and allow the even distribution of the enzymic oil.

Thus, thanks to these operations, when the thread composed of the mixture of first and second fibres is spun, the first fibres are humidified and imbibed with enzymic oil in a close and even manner and do not exhibit zones wherein, due to humidity and/or to the oil that have concentrated, the second fibres that are soluble may dissolve, sticking to each other and to the first fibres and preventing

proper processing; in fact, should this happen, it would be necessary to discard this thread containing the first and the second fibres partially or totally stuck to one another.

In the practice, using the process according to the finding it is possible to make mixtures having even very high percentages by weight of soluble fibres and above 20%.

Advantageously, once the first fibres and the second fibres have been mixed making a sliver consisting of a mixture of first and second fibres and before spinning this sliver, the sliver is subject to recombing, so as to mix the first and the second fibres in a closer and more even manner; this ensures the quality of the end threads and fabrics.

After having spun the sliver and made the thread consisting of a mixture of first and second fibres, the thread consisting of a mixture of first and second fibres is subject to a process vaporization process so as to stabilise the twist.

During the vaporization, the thread is wound on cardboard tubes (spools) that are arranged vertically and in a regular manner in layers; a large grain absorbing fabric is arranged between the layers.

This allows preventing condensation problems, dripping and localised temperature (thanks to the cardboard that absorbs any water that may form) and to the fabric that absorbs any water drops that may form and drop onto the tubes located underneath.

The process described allows making a thread which is also an object of the present invention; by such thread it is possible to make a fabric by the process for making a fabric described hereinafter.

The process for making the fabric consists in weaving the thread consisting of a mixture of first and second fibres making a fabric and subsequently, dissolving the second soluble fibres, so as to obtain a fabric consisting of the first fibres only.

Reference shall be made hereinafter to the case of second fibres consisting of InPVA fibres; in this case, the fabric is immersed in a water bath having a ratio between fabric weight and water amount less than 1:25 and preferably equal to 1:30.

Such bath allows obtaining considerable water saving compared to the traditional baths that use 1 :50 ratios.

The fabric is immersed in the cold water bath - for example at room temperature - which is added with acetic acid to obtain a PH 5.5; the water is then warmed to obtain a temperature that takes a value within the range between 65-90 ⁰ C according to the type of PVA thread and the compactness of the fabrics produced, and the fabric is left to spin in the bath for a time comprised between 25-50 minutes; also this time may be regulated according to the type of PVA and to the fabric compactness.

The bath is then cooled with the input of cold water and drained.

Afterwards, the fabric is washed, the first washing bath (after the dissolving) is made with hot purified water having a temperature of about 40 ⁰ C for a time of 10 minutes, then it is drained.

Two more washing baths are carried out with cold purified water.

After these operations, the fabric does not have the second fibres anymore and it is ready: to be finished or to be dyed in the desired colour.

The fabric thus formed is very light, soft and bulky since the second threads are dissolved and the fabric remains composed of the first threads only.

Figure 2 shows a thread produced according to the finding and wherein the second fibres have been dissolved; in this figure, reference numeral 1 indicates the thread as a whole and reference numeral 2 the first fibres.

As is clear from the figures, the overall section of thread 1 is the same both when the second threads 3 have not been dissolved yet (figure 1), and after they have been dissolved (figure 2); this ensures bulkiness and lightness of the thread and of the fabric made with such thread.

An option is, before making the fabric, the first thread composed of a mixture of first and second fibres is twisted with a second thread made of soluble fibres only in an environment wherein the first fibres are not soluble; for example, the second thread is composed of the second fibres, that is, of fibres equal to the soluble fibres made with the first thread.

The twisted thread composed of the first thread and of the second thread is then woven.

The next step wherein the soluble threads are dissolved allows obtaining a fabric composed of the first threads only and therefore, very light, soft and bulky.

Of course, the first fibres may either be of a natural colour or dyed.

The fabric composed of natural and/or artificial and/or synthetic and/or mineral fibres, either pure or mixed with each other, made by the process described is also an object of the present invention.

In the practice, the materials used as well as the sizes, can be whatever, according to the technical requirements and to the prior art.