TITLE

BIOCERAMIC PILE FABRIC AND METHOD FOR MANUFACTURING IT TECHNICAL FIELD

The present invention belongs to the sector of textile industry, and specifically to the sector of special fabrics. More specifically, the present invention belongs to the sector of fabrics that comprise fibres including bioceramic particles.

In particular, the present invention belongs to the sector of pile fabrics wherein at least a part of fibres comprises bioceramic particles.

PRESENT STATUS OF THE ART

Technologies have been developed for some time aiming at exploiting bioceramics; the latter are mineral mixtures, mainly oxide- and silicate-based mixtures, some beneficial properties of which are known which originate from the capability of bioceramic particles of reflecting far infrared radiations (FIR), i.e. radiations featuring a wavelength in the range from 4 micrometres (pm) to 1mm (corresponding to a frequency range from about 300 GHz to about 20 THz) .

It is known for a long time that reflection of FIR radiations has very beneficial effects on human body and consequently a problem arose of how to exploit this interesting property of bioceramics, by integrating particles of such materials in textile products intended for being put close to human body, such as, for example, underwear and clothes, as well as blankets or upholstery of stuffed sitting room suites.

A possible solution is disclosed in WO2009124367 A2 which illustrates a woven fabric in whose fibres bioceramic microparticles are "imbedded". This fabric is obtained by immersing a textile product in a thermal bath containing powdered bioceramics, so that such microparticles infiltrate the textile fibres, however without making up true physical or chemical bonds therewith. A main disadvantage of such solution is in that a thus impregnated fabric very rapidly loses its own contents of bioceramic particles, both because of wear caused by rubbing and, above all, because of subsequent washings .

In order to provide a lasting reflecting effect, special fibres made from a polymeric material have been produced which incorporate bioceramic particles internally thereto. Such fibres are used to produce fabrics.

A solution of this kind is disclosed in patent application WO2018051285 Al, which describes a woven fabric wherein the weft threads or, alternatively, the warp threads incorporate particles of a bioceramic material.

However, fabrics of such kind are not suitable for manufacturing articles of clothing to be worn not in direct contact with skin, such as for example overcoats and suits, but they are only effective if used to manufacture articles that adhere to human body, such as underwear.

The reason for this is because the polyester fibres that contain bioceramics generally feature a very small diameter, in the order of 1.5 pm, that is to say very much smaller than the diameter of normal textile fibres, which is in the order of 20 pm and fabrics obtained by weaving fibres of this kind consequently feature a low grammage, in general in a range from 70gr/sqmt to lOOgr/sqmt, and consequently such fabrics shall necessarily adhere to human body and be in contact with skin in order for infrared radiations to provide a sufficiently high reflecting effect. On the other hand, it is not possible to use bioceramic fibres with diameters exceeding 1.5 pm, because they would result in fabrics featuring an excessive weight and simultaneously being little elastic and little flexible, hence featuring very poor wearability.

In order to try and increase the capability for such fabric of reflecting FIR radiations, it has been devised to incorporate bioceramic particles both in the weft threads and in the warp threads, so as to increase the overall contents of bioceramics incorporated in a fabric.

However, such technical solutions have been demonstrated to be ineffective because the crossing of the weft and warp threads, both filled with bioceramics, being substantially perpendicular results in a partial cancellation of the reflecting effect of infrared radiations, thus originating an effect that is opposite to the expected one.

A different approach is disclosed in Italian patent IT0001419414 , which describes an innovative fabric obtained by way of a "pile" processing, which consists of fixing loose pure wool fibres, woven with polymeric fibres filled with bioceramic particles, to a reticular support fabric made from polyester fibres.

This type of processing makes it possible to obtain articles of clothing containing an amount of bioceramic particles that is much higher than the woven fabrics previously known in the art, and consequently the reflecting capability of FIR radiations in the thus obtained textile products is sufficiently high as to provide the desired beneficial effects, even if such fabric is not put in direct contact with body.

However, in the above-described solution, the fibres filled with bioceramic particles are to be woven with pure wool or pure virgin wool fibres before being fixed to the reticular support fabric. It is known that wool fibres are very delicate and that articles made from such material feature a number of disadvantages, including shrinkage upon being washed, easy deformability, and felting over time.

Another important disadvantage of the solution described in IT0001419414 is in that the support fabric features a reticular structure, i.e. it is made up of a set of weft and warp threads woven perpendicularly to each other: however, such weft and warp threads being woven with each other are not suitable for stably binding the thin loose pile fibres, which might easily detach from the support fabric, both during washing and afterwards, because of rubbing.

So, the problem of realizing a fabric integrating bioceramic particles that is capable of maximizing the beneficial effects of reflection of FIR radiations, even if not put in direct contact with skin, and is lasting, lightweight, optimally wearable, easily washable and wear resistant, independently of the material that such fabric is made from, be it of natural, artificial, or synthetic origin, is still to be solved.

The above-described problems and others known to those skilled in the art have been solved by a knitted pile fabric as described and claimed below; a method is also disclosed and claimed below for manufacturing said fabric and textile products comprising such fabric.

It is worth stating first that, in the present patent document, by "woven fabric" or "reticular fabric" we mean a fabric of a known type, obtained by orthogonally weaving two sets of threads, called weft and warp respectively.

Also, the expression "knitted fabric" will be used below to indicate a type of fabric, also known to those skilled in the art, consisting of superimposed lines of yarns, each of which follows a meander-like path, i.e. comprises a sequence of eyelet loops, where the eyelets of one line cross the inside of the eyelets of the line below.

Typically, the segments of through-passing yarns connecting two superimposed lines, arranged in such a way as to form a grid of "V"s one within the other are visible on the front side of a knitted fabric.

As known to those skilled in the art, knitted pile weaving uses a knitted support fabric, from which thin loose fibres ("pile") perpendicularly project to form an artificial fleece, which fibres are firmly bound to the support fabric, by passing through the eyelets of the stitches of the latter. It is also worth stating that, in the present patent document, by "artificial fleece" we mean a product that imitates the appearance of an animal fur and can be made up of synthetic, natural, or artificial fibres or a heterogeneous mixture of such fibres.

OBJECTS AND SUMMARY OF THE INVENTION

An object of the present invention is to overcome the drawbacks of fabrics formed of bioceramic fibres presently known and of textile products manufactured by using such fabrics, by providing a knitted pile fabric comprising a big amount of fibres of bioceramic particles and capable of maximizing emission and reflection of FIR radiations at the same wavelengths as those emitted by mammalian bodies, also thanks to the prevailing orientation of said fibres containing bioceramics .

In particular, an object of the present invention is to provide a fabric of the above-described type for manufacturing clothes capable of providing the beneficial effects given by the presence of bioceramics, even when such clothes are not in direct contact with skin, but are worn above other clothes.

Another object of the present invention is to provide a knitted pile fabric comprising bioceramic particles that is lasting, lightweight, provided with optimal wearability, easily washable and wear resistant, made from a material having a natural, artificial, or synthetic origin.

Advantageously, the knitted pile fabric according to the present invention comprises an artificial fleece formed of a heterogeneous mixture of fibres of a polymeric material in which bioceramic particles are incorporated, with a diameter of about 1.5 pm, and fibres of other materials, be they natural or artificial, with a greater diameter, such as, for example, wool, cotton, kapok, linen, tencel®, polyester, etc .

Preferably, the percentage of such polymeric fibres incorporating bioceramic particles ranges from 30% to 70% of the number of overall fibres making up the artificial fleece. Since such fleece consists of a very high number of very thin and lightweight fibres, the amount of bioceramic in the fabric is much higher than the typical amount of known woven fabrics .

According to a technical process known to those skilled in the art, such fibres of a polymeric material are obtained by making granules of a polymeric material, for example polyester, melt together with a powdered bioceramic material, so as to obtain, through an extrusion process, long filaments having a diameter of about 1.5 pm, consisting of a polymeric material containing bioceramic particles, which are texturized and cut into approx. 5cm long sections. Such heterogeneous mixture of thin bioceramic fibres and thicker natural or artificial fibres is processed in a carding machine, wherein it is made thinner and the fibres are partially rectified, so as to obtain a tubular carded strip having a diameter of about 2 to 3 cm, commonly referred to as "tops".

In order to create a knitted pile fabric, a circular textile machine is used, suitable for producing knitted pile fabrics and provided with a plurality of knitted thread feeding points, wherein the yarn is fed to the independent movable needles of the machine for creating a support fabric, and a plurality of tops feeding points, wherein the fibres, be they bioceramic or not, feed the mechanical members suitable for inserting them into the stiches of the support fabric, in order to obtain an artificial fleece.

Such circular textile machine basically exploits a technology that is known to those skilled in the art to obtain a knitted support fabric by binding thereto the loose approx. 5cm long fibres extracted from the tops. In particular, specially developed mechanical members wind said fibres about the stiches of the support fabric, and make them project from the front side of such fabric. Subsequently, the pieces of such fibres, projecting from the front side of the knitted fabric, are cut to a predetermined length, often equal to 1.2cm, so as to equalize the thickness of the artificial fleece.

Then the thus obtained fabric can be cut, shaped, or further processed to obtain textile products of different types.

In order to obtain an artificial fleece, it is not possible to exclusively use fibres of a bioceramic polymeric material because, owing to their extreme thinness, they would clog the tips of the carding machine that prepares the tops and the combing-wheels of the circular knitting pile machine. Very advantageously, the knitting process that characterizes the present invention stands out for its great elasticity and high density of fibres as compared to the woven fabrics known in the present status of the art. This achievement is obtained because the knitting process makes it possible for a fabric to extend in all directions.

The high density of fibres of the fabric according to the present invention maximizes the reflecting/emitting effect of FIR radiations. The fibres of the fleece containing bioceramic being mostly oriented in a direction orthogonal to the plane of the knitted fabric also contribute to increase the reflecting/emitting effect.

Surprisingly, the fabric according to the present invention is very lightweight, warm, elastic, and comfortable to wear, besides being wear resistant and lasting. As a matter of fact, the grammage of such fabric can be as high as about 700gr/sqmt, depending on the quality and quantity of fibres used: typically, the support fabric features a grammage of about 120-140 gr/sqmt to which 150 to 500gr/sqmt of artificial fleece are to added.

According to a possible embodiment of the present invention, the knitted support fabric is also comprised of fibres of a polymeric material incorporating bioceramic particles.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a front view of a fabric according to the present invention, wherein the knitted support fabric (1) is visible, whereas the artificial fleece (2) has not been shown here in order to make the figure more understandable.

Figure 2 is a cross section of the fabric shown in figure 1 along the line II-II; the figure shows the support fabric (1) and the artificial fleece (2), the latter comprising fibres (4) and special fibres (3) .

Figure 3 is a cross section of the fabric shown in figure 1 along the line III-III.

DETAILED DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

The scope of the present invention is a knitted pile fabric consisting of a knitted support fabric (1) and an artificial fleece (2) comprising fibres (4) and special fibres (3), the latter incorporating bioceramic particles.

Further scopes of the present invention are a method for realizing said knitted pile fabric and textile products comprising the latter.

The knitted support fabric (1) is either made up from natural, artificial, or synthetic fibres or a combination thereof .

Such artificial fleece (2) is made up from polymeric special fibres (3) incorporating bioceramic particles and other fibres (4), not incorporating bioceramic particles, which are either natural, artificial or synthetic or a combination of fibres of various natures.

In the embodiment here described, said special fibres (3) have a diameter smaller than said fibre (4); preferably, the diameter of said special fibres (3) is smaller than or equal to 3.0 pm, more preferably smaller or equal to 1.5 pm, whereas the diameter of said fibres (4) is greater than or equal to 15 pm.

In order to maximize the beneficial effects of bioceramic particles, said artificial fleece (2) is formed of special fibres (3) in a maximum percentage of 70% of the total fibres making up the artificial fleece (2) itself.

Depending on the material used for implementing the support fabric (1) and the amount of fibres (4) and special fibres (3) used, the grammage of the knitted pile fabric according to the present invention can be as high as 700gr/sqmt. In a preferred version of the embodiment, the support fabric (1) has una grammage equal to 140gr/sqmt and the artificial fleece (2) has a grammage of 500gr/sqmt.

In a special embodiment, said support fabric (1) is also made up of yarns at least partially formed of fibres of a polymeric material incorporating bioceramic particles. Another scope of the present invention is a textile product completely or partially implemented by using the above- described fabric by using techniques commonly known to those skilled in the art .

The method for implementing a fabric according to the present invention comprises the following steps:

a. inserting a powdered bioceramic material into a plurality of granules of a polymeric material;

b. melting such granules of a polymeric material and powdered bioceramic, thus obtaining a mixture formed of polymers and bioceramic particles;

c. hot-extruding said mixture by way of an extruder and forming a thin filament, preferably having a diameter equal to 1.5 pm;

d. texturizing said thin filament and cutting it into approx. 5 centimetres long sections, thus obtaining a plurality of special fibres (3) containing bioceramic particles ;

e. mixing said special fibres (3) with fibres (4) of a natural, artificial, or synthetic origin, not incorporating bioceramic particles;

f. inserting the heterogeneous mixture of said special fibres (3) and fibres (4) into a carding machine, so as to obtain a plurality of carded strips, each having a diameter of about 2-3 cm;

g. manufacturing a tubular knitted pile fabric by using a circular knitting pile textile machine, fed with a plurality of yarns, to produce the support fabric (1), and with a plurality of said carded strips, to produce said artificial fleece (2 ) ;

h. shaving and levelling the artificial fleece (2) .