Metallized textile substrates, process for preparing the same and related apparatus.

The present invention relates to metallized textile substrates such as e.g. woven fabrics, non-woven fabrics and knitted fabrics, comprising or alternatively consisting of natural fibers of proteic or vegetable origin and fibers of artificial and synthetic origin, having conductivity and electromagnetic shielding properties as well as other intrinsic properties of metals used, such as e.g. the antibacterial property that can be imparted to a textile substrate using silver. The present invention further relates to a process for preparing said metallized textile substrates. The present invention eventually relates to an apparatus for preparing said metallized textile substrates.

It is generally known that a textile fabric can be metallized. However, known processes are not without limitations and drawbacks which strongly reduce the widespread use thereof.

One of the drawbacks consists in that a metallized fabric manufactured with currently known processes undergoes during its preparation a hardening process contributing to make the fabric lose its tactile properties and, as a result, is quite unsuitable for use in the fashion industry or in the field of sports or technical fabrics. Moreover, it should be pointed out that, due to process yields that are not always optimal or not always easy to be optimized, known fabric metallization processes require an excessive use of amounts of metals, acid or basic substances, additives and solvents both during the pre-treatment and in the actual treatment of the fabric, which do not make these metallization processes cheap and/or environmentally safe.

Therefore, professionals in this industry feel the need to have a fabric with unchanged tactile properties after its metallization as well as a process and an apparatus for its preparation that are cheap, environmentally safe and able to impart conductivity and electromagnetic shielding properties as well as other intrinsic properties of metals used such as e.g. the antibacterial property. Last but not least, professionals feel the need to have a metallized fabric having its own heat shielding and/or insulation properties (which are highly desired and required in the field of performing fabrics for extreme sports activities) such as e.g. in the case of a textile substrate comprising metallized wool fibers, since thanks to its nature wool is already an excellent natural insulating agent and the metallization treatment combines the intrinsic properties of the fiber and the property of metals such as e.g. copper or silver of screening heat lost by irradiation from the human body. The above aims at preserving the softness, comfortable fit and aesthetic appearance of a metallized textile substrate as important features since these fabrics are designed for use in the field of sports and casual clothing.

After an intensive and long research and development activity, the Applicant has responded to the above mentioned needs by developing a process and an apparatus for preparing said metallized textile substrates. The textile substrates are chosen among woven fabrics (e.g. fabrics with weft and warp yarns), non-woven fabrics and knitted fabrics comprising or alternatively consisting of natural fibers (or yarns or filaments) of proteic origin such as e.g. wool or silk; natural fibers of vegetable origin such as e.g. cotton or linen; artificial fibers such as e.g. viscose or rayon acetate and fibers of synthetic origin such as e.g. polyester or nylon. Fabrics can include as weft and/or warp fibers or yarns or filaments one or more carbon fibers or yarns or filaments arranged either alone or together with e.g. other weft and/or warp fibers or yarns or filaments of natural proteic origin, of natural vegetable origin, of artificial origin or of synthetic origin. Metallization involves the use of metals which, thanks to their intrinsic chemical and/or physical properties, can be deposited onto said textile substrates by chemical and galvanic (or electrochemical) route. For instance, (chemical and galvanic) metallization can involve the use of metals such as nickel, copper, zinc, silver, cobalt, lead and gold, or a nickel/cobalt bath (e.g. Nichel Speed 200 g/l N1SO4 and 100 g/l C0SO4) or a ternary bath such as e.g. a white bronze bath.

An object of the present invention consists in a process and an apparatus for preparing metallized textile substrates such as e.g. woven fabrics, non-woven fabrics and knitted fabrics comprising or alternatively consisting of natural fibers of proteic or vegetable origin, of fibers of artificial origin and of fibers of synthetic origin; said metallized fabrics having conductivity, electromagnetic shielding, heat shielding and/or insulation properties, high tactile softness and comfortable fit and other intrinsic properties of metals used such as e.g. an antibacterial properties as in the case silver is used. Said textile substrates are chosen among woven fabrics (e.g. fabrics with weft and warp yarns), non-woven fabrics and knitted fabrics comprising or alternatively consisting of natural fibers (or yarns or filaments) of proteic origin such as e.g. wool or silk; natural fibers of vegetable origin such as e.g. cotton or linen; artificial fibers such as e.g. viscose or rayon acetate and fibers of synthetic origin such as e.g. polyester or nylon. Fabrics can include as weft and/or warp fibers or yarns or filaments one or more carbon fibers or yarns or filaments arranged either alone or together with e.g. other weft and/or warp fibers or yarns or filaments of natural proteic origin, of natural vegetable origin, of artificial origin or of synthetic origin.

Another object of the present invention consists in said metallized textile substrates having the characteristics as listed in the appended claims. Preferred embodiments of the present invention are described below as mere examples in order to disclose the scope of the present invention, though without limiting in any way the scope thereof.

Preferably, metals used in the present invention are those with a coefficient of thermal emissivity not above 0.2. Some preferred embodiments refer to textile substrates metallized by using metals such as nickel, copper, zinc and silver.

The process for preparing the metallized textile substrates forming the object of the present invention comprise a sequence of steps as disclosed below.

An embodiment of the process for preparing said metallized textile substrates is implemented by using an apparatus as shown in Figures 1 , 1A and 1 B.

Figure 1 shows a side view of a section of the apparatus as a whole, wherein tanks V1 to V10 are indicated. Figure 1 A shows a side view of a section of the apparatus, wherein tanks V1 to V6 are indicated.

Figure 1 B shows a side view of a section of the apparatus, wherein tanks V7 to V10 are indicated. Figure 2 shows a side view of tanks V7 in which galvanic (or electrochemical) metallization is carried out. Figures 3-6 refer to the evaluation of sample of metallized fabric 1 with IR emission.

The process comprises a pre-treatment step (referred to for shortness' sake as F1). The pre-treatment step is not shown in the Figures. The pre-treatment step includes a chemical treatment (referred to for shortness' sake as F1.1) together with a physical/mechanical treatment (referred to for shortness' sake as F1.2). Said chemical F1.1 and physical/mechanical F1.2 treatment are carried out together. Said treatments F1.1 and F1.2 can act upon the molecular structure of the fibers present in the textile substrates in order to create amorphous areas (micro holes and/or openings) on the surface of the fibers themselves so as to promote the penetration of the following treatment baths or solutions provided for in the following process steps, such as: an activation step (referred to for shortness' sake as F2), a catalytic step (referred to for shortness' sake as F3), a metallization step by chemical route (referred to for shortness' sake as F4) together with a metallization step by galvanic or electrochemical route (referred to for shortness' sake as F5).

In practice, the pre-treatment step F1 (F1.1 + F1.2) acts upon the crystalline and amorphous areas present in the molecular structure of the fibers, thus increasing the amorphous component to the detriment of the crystalline component.

In one embodiment, the chemical treatment F1.1. of said pre-treatment step F1 involves the use of acids or bases (depending on the origin of the fibers to be treated) and of a mechanical traction generated by some mechanical means present in the apparatus. Said pre-treatment step F1 can be made continuously, together with the other steps described below, or discontinuously. In both cases (continuous mode or discontinuous mode), the textile substrate is always subjected to a mechanical traction generated by mechanical means, such as e.g. a plurality of pairs of opposed cylinders, which can apply to the fabric under processing a stretching traction in the direction of the warps yarns and a squeezing or pressure force on the open width of the textile substrate itself. If said pre- treatment step F1 is made discontinuously, a machine for treating the open width of the fabric can be used. Then, the textile substrate pre-treated with step F1 in discontinuous mode is fed to the pair of cylinders C1C of Fig. 1A. For instance, in the case of a textile substrate made of natural fibers of proteic origin, such as e.g. wool or silk, the pre-treatment step F1 is previously carried out in discontinuous mode. For instance, in the case of a textile substrate made of natural fibers of vegetable origin, such as e.g. cotton or linen, the pre-treatment step F1 beyond being separately made in discontinuous mode is also carried out in the tank V1. The tank V1 contains the solution S2 and is characterized by an acid pH value. The acid pH value in the chemical treatment F1.1 , together with the traction system present in the apparatus, by means of the system made up of the pairs of cylinders together with the cylinders in the tank V1 (physical/mechanical treatment F1.2), make up the complete pre- treatment. Said treatments F1.1 and F1.2 are carried out together simultaneously on the fabric under processing so as to combine pH and temperature conditions with the continuous mechanical traction.

The chemical treatment F1.1 carried out under given operating conditions of temperature, time and pH can act upon the fibers by attacking them and thus increasing the amorphous areas (i.e. the areas which are more susceptible to be penetrated by chemical reagents used in the following processing steps and to let metal ions present in the salts used to get anchored or fastened thereon).

At the same time as the chemical treatment F1.1 , a physical/mechanical treatment F1.2 is carried out, in which the fibers, chemically treated as described above, are subjected to a mechanical pressure/traction increasing the susceptibility of the fibers to be penetrated by the treatment baths. Said mechanical pressure/traction can be carried out by using a series of pairs of cylinders together with a series of opposed cylinders, such as those shown by way of example in tank V1 in Figure 1 A.

As a matter of fact, in the case of textile substrate comprising or alternatively consisting of synthetic fibers, the pre-treatment step is also carried out in tank V1 in an aqueous solution containing acids, e.g. hydrochloric acid, having a pH of 0.5 to 2.5.

Then, said pre-treatment step F1 is followed by an activation step (referred to for shortness' sake as F2). The activation step F2 can be carried out in the apparatus of Figure 1A.

The activation step F2 is carried out in a tank V1. In the activation step V2 a textile substrate T, in the form of a piece of fabric having e.g. a height of 1.50 meters or 1.70 meters or 1.80 meters, pre-treated as referred to above (F1.1 +F1.2), is fed through the pair of cylinders C1C to a tank V1. The tank V1 comprises a first upper row of cylinders and a second lower row of cylinders, which are e.g. spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C1 , C3, C5, C7, C9, is arranged above the second row of cylinders, which comprises e.g. cylinders C2, C4, C6, C8, C10. Said first and second row of cylinders are immersed in a solution S2 contained in tank V1 , except for cylinder C1. The textile substrate T, by means of the pair of cylinders C1C, reaches cylinder C1 and then gets into solution S2 contained in tank V1. The textile substrate T remains immersed in tank V1 thanks to the presence of cylinders C2-C10 building a path (up and down) inside tank V1 having a length of e.g. 10 meters to 20 meters.

Then, the textile substrate T leaves tank V1 and reaches the pair of cylinders C2C. The pairs of cylinders C1C and C2C are motorized and can be made of steel coated with a rubber resistant to chemicals. The pairs of cylinders C1C and C2C, as well as all the other pairs of cylinders described here, are pairs of overlapping cylinders, i.e. made up of two cylinders with parallel axes of rotation, which enable the textile substrate T to slide. The function of the pairs of cylinders C1C and C2C is to maintain the textile substrate T under continuous traction. The function of the pair of overlapping cylinders C2C is to squeeze the textile substrate T so as to remove from it the excess of solution S2 and promote reagent penetration.

In the activation step F2 the textile substrate T, already subjected to said chemical treatment F1.1 and to said mechanical/physical treatment F1.2, is subjected to an activation treatment F2 so as to activate the surface of the textile substrate T for the following process steps, such as: a catalytic step (referred to for shortness' sake as F3), a metallization step by chemical route (referred to for shortness' sake as F4) together with a metallization step by galvanic or electrochemical route (referred to for shortness' sake as F5). In one embodiment of said activation step F2, the activation treatment F2 involves the use of an aqueous solution S2 contained in said tank V1 , comprising a water soluble tin salt such as e.g. tin (II) chloride having an electronegativity value Z of 1.96. It should be pointed out that other soluble tin salts or other soluble salts of metal ions other than tin can also be used provided that they have an electronegativity value Z of 1.90 to 1.96.

The textile substrate T is immersed into said solution S2 comprising an amount of 5 ml/l to 20 ml/l, e.g. 10 ml/l, of 37% hydrochloric acid, and an amount of 5 g/l to 15 g/l, e.g. 7 g/l or 10 g/l, of tin (II) chloride at a temperature between 20°C and 30°C, or between 25°C and 35°C, preferably between 23°C and 28°C, at a pH value between 1 and 5, preferably between 1 and 2 or between 1 and 1.50, and for a residence time of the textile substrate in the solution S2 (or immersion time) between 5 and 20 minutes, preferably between 10 and 15 minutes. The textile substrate T immersed in the solution S2 moves forward from the pair of cylinders C1C to the pair of cylinders C2C along tank V1 by means of said two rows of cylinders at a constant speed of e.g. 1 to meter/minute to 2 meters/minute.

When the textile substrate T leaves the pair of cylinders C2C, it has ended the activation step F2 and is ready to be fed to the tank V2 to be preferably subjected to a rinsing step. The tank V2 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C11 and C13, is arranged above the second row of cylinders, which comprises e.g. cylinders C12 and C14. Said first and second row of cylinders are immersed in a Sris (Sris (rinsing solution) contained in tank V2, except for cylinder C11. The textile substrate T, by means of the pair of cylinders C2C, reaches cylinder C11 and then gets into solution Sris contained in tank V2. The textile substrate T remains immersed in tank V2 thanks to the presence of cylinders C12-C14 building a path (up and down) inside tank V2 having a length of e.g. 4 meters to 8 meters.

Then, the textile substrate T leaves tank V2 and reaches the pair of cylinders C3C. The pairs of cylinders C2C and C3C are motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pairs of cylinders C2C and C3C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C3C is also to squeeze the textile substrate T so as to remove from it the excess of solution Sris. The solution S _r i _S is a demineralized water bath at a temperature of 20°C to 30°C, preferably 25°C.

After said rinsing step carried out in tank V2, a catalytic step F3 is carried out. The catalytic step F3 is carried out in a tank V3. In the catalytic step F3, for instance, the textile substrate T, rinsed as referred to above, is fed through the pair of cylinders C3C to a tank V3. The tank V3 comprises a first upper row of cylinders and a second lower row of cylinders, which are e.g. spaced apart from each other for a distance e.g. of 0.5 meters to 2 meters. The first row of cylinders, which comprises e.g. cylinders C15, C17, C19, C21 , is arranged above the second row of cylinders, which comprises e.g. cylinders C16, C18, C20, C22. Said first and second row of cylinders are immersed in a solution S3 contained in tank V3, except for cylinder C15. The textile substrate T, by means of the pair of cylinders C3C, reaches cylinder C15 and then gets into solution S3 contained in tank V3. The textile substrate T remains immersed in tank V3 thanks to the presence of cylinders C16-C22 building a path (up and down) inside tank V3 having a length of e.g. 4 meters to 16 meters.

Then, the textile substrate T leaves tank V3 and reaches the pair of cylinders C4C. The pairs of cylinders C3C and C4C are motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pairs of cylinders C3C and C4C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C4C is also to squeeze the textile substrate T so as to remove from it the excess of solution S3.

In the catalytic step F3 the textile substrate T, already subjected to said chemical treatment F1.1 , to said mechanical/physical treatment F1.2 and/or to said activation treatment F2, is subjected to a catalytic treatment F3 so as to catalyze the surface of the textile substrate T for the following process steps, such as: a metallization step by chemical route (referred to for shortness' sake as F4) together with a metallization step by galvanic or electrochemical route (referred to for shortness' sake as F5).

In one embodiment of said catalytic step F3, the catalytic treatment involves the use of an aqueous solution S3 contained in said tank V3, comprising a water soluble palladium salt such as e.g. palladium (II) chloride having an electronegativity value Z of 2.20. It should be pointed out that other soluble palladium salts or other soluble salts of metal ions other than palladium can also be used provided that they have an electronegativity value Z of 2.15 to 2.60 in the second case; for instance, palladium and gold can also be used.

The textile substrate T is immersed into said solution S3 comprising an amount of 0.5 ml/l to 5 ml/l, e.g. 1 ml/l, of 37% hydrochloric acid, and an amount of 0.05 g/l to 0.5 g/l, e.g. 0.1 g/l or 0.2 g/l or 0.3 g/l, of palladium chloride at a temperature between 20°C and 30°C, or between 25°C and 35°C, preferably between 23°C and 28°C, at a pH value between 1 and 4, preferably 2 to 3 or 2 to 2.5, and for a residence time (or immersion time) between 1 minute and 20 minutes, preferably between 5 minutes and 10 minutes.

The textile substrate T immersed in the solution S3 moves forward from the pair of overlapping cylinders C3C to the pair of overlapping cylinders C4C along tank V3 by means of said two rows of cylinders at a constant speed of e.g. 1 to meter/minute to 2 meters/minute.

The ions of the little noble metal, e.g. tin ions of the tin (II) chloride salt, are absorbed onto the surface of the fibers making up the textile substrate T as a result of the treatment including immersion of the textile substrate T into said solution S2. Then, as a result of the treatment including immersion of the textile substrate T into said solution S3, the ions of the noble metal, e.g. palladium ions of the palladium (II) chloride salt, are absorbed onto the surface of the fibers and are therefore in contact with the ions of the little noble metal. The ions of the little noble metal (Sn ²⁺ ) and the ions of the noble metal (Pd ²⁺ ), in contact with each other or arranged close to one another, active the surface of the textile substrate due to their different electronegativity [Sn ²⁺ + Pd ²⁺ → Sn ⁴⁺ + Pd ⁰ ]. In practice, considering the intrinsic electronegativity difference of the two ions used, the palladium ion will be deposited onto the tin ion (or close thereto) and the textile substrate will have on its surface areas made up of palladium in the form of metallic Pd°. As a result, the textile substrate will have a higher inclination (catalyzation) to the following metallization step by chemical route (referred to for shortness' sake as F4) together with a metallization step by galvanic or electrochemical route (referred to for shortness' sake as F5). The activation step F2 carried out in tank V1 using solution S2, and the catalytic step F3 carried out in tank V3 using solution S3 should be carried out in separate tanks, preferably spaced apart with a rinsing step, so as to enable the two metal ions to be separately absorbed or deposited onto the fibers or yarns or filaments. The advantage of carrying out step F2 separately from step F3 is related to a higher control of the amounts of metal cations of the solution S3 which are absorbed or deposited, thus avoiding useless wasting of excesses of metal cations of the solution S3 and conversely saving on process costs and obtaining lower pollution levels. Moreover, the formation of colloids or aggregates on the fibers or yarns or filaments, which hinders the success of the following steps, in particular of the following step F4, is avoided. Steps F2 and F3 are carried out, as well as the remaining steps F4 and F5, by subjecting the textile substrate to a continuous mechanical traction in an e.g. acid or basic medium, which enables to maintain or increase the amorphous areas and to obtain an "activated" surface of the fibers or yarns or filaments enabling e.g. an optimal absorption or deposition of tin (II) onto the surface of the fiber or yarn or filament, thus ensuring a uniform distribution of anchoring points for the following cation, e.g. palladium (II). The different electronegativity results in a uniform and cheap formation of metallic palladium (0) (and tin (iv)). Advantageously, steps F2 and F3 are carried out at a temperature of 30°C to 40°C, preferably at 35°C.

When the textile substrate T leaves the pair of cylinders C4C, it has ended the catalytic treatment F3 and is ready to be fed to the tank V4 to be subjected to a rinsing step. The tank V4 comprises a first upper row of cylinders and a second lower row of cylinders, which are e.g. spaced apart from each other for a distance e.g. of 1 meters to 2 meters. The first row of cylinders, which comprises e.g. cylinders C23 and C25, is arranged above the second row of cylinders, which comprises e.g. cylinders C24 and C26. Said first and second row of cylinders are immersed in a solution Sris contained in tank V4, except for cylinder C23. The textile substrate T, by means of the pair of cylinders C4C, reaches cylinder C23 and then gets into solution Sris contained in tank V4. The textile substrate T remains immersed in tank V4 thanks to the presence of cylinders C24-C26 building a path (up and down) inside tank V4 having a length of e.g. 4 meters to 8 meters.

Then, the textile substrate T leaves tank V4 and reaches the pair of cylinders C5C. The pairs of cylinders C4C and C5C are motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pairs of cylinders C1C, C2C, C3C, C4C and C5C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C5C is also to squeeze and remove from it the excess of solution Sris. The solution Sris (rinsing solution) is a demineralized water bath at a temperature of 20°C to 30°C, preferably 25°C.

After said rinsing step carried out in tank V4, a metallization step (referred to for shortness' sake as F4) is carried out in tank V5. In the metallization step, for instance, the textile substrate T, rinsed as referred to above and coming from the tank V4, is fed through the pair of cylinders C5C to a tank V5. The tank V5 comprises a first upper row of cylinders and a second lower row of cylinders, which are e.g. spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C27, C29, C31 , C33, C35, C37, C39, is arranged above the second row of cylinders, which comprises e.g. cylinders C28, C30, C32, C34, C36, C38, C40. Said first and second row of cylinders are immersed in a solution S4 contained in tank V5, except for cylinder C27. The textile substrate T, by means of the pair of cylinders C5C, reaches cylinder C25 and then gets into solution S4 contained in tank V5. The textile substrate T remains immersed in tank V5 thanks to the presence of cylinders C28-C40 building a path inside tank V5 having a length of e.g. 14 meters to 28 meters. Then, the textile substrate T leaves tank V5 and reaches the pair of cylinders C6C. The pairs of cylinders C5C and C6C are motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pairs of cylinders C5C and C6C is to maintain the textile substrate T under continuous traction. The function of the pair of cylinders C6C is also to squeeze the textile substrate T so as to remove from it the excess of solution S4.

The metallization step by chemical route F4 involves the deposition and formation of a metal coating or film onto the textile substrate T coming from a pre-treatment step F1 , an activation step F2 and a catalytic step F3.

In one embodiment of said metallization step, the metallization treatment by chemical route F4 involves the use of a water soluble salt of the metal to be deposited onto the textile substrate. Said salt can release the metal ions once dissolved into the aqueous solution S4.

In one embodiment, the textile substrate T coming from said catalytic step F3 and said rinsing step, is contacted with an aqueous solution S4 comprising e.g. a water soluble salt of the metal to be deposited such as e.g. a soluble nickel or copper or silver or cobalt salt and a reducing agent such as e.g. a sodium hypophosphite. The reducing agent can start an oxidoreduction reaction with the metal ion present in said soluble salt, and therefore the reducing agent can provide the electrons required to turn the metal ions with positive oxidation number (e.g. Ni ²⁺ or Cu ²⁺ ) to a metal with oxidation number zero (e.g. metallic nickel or copper) directly on the fibers of the textile substrate previously activated with e.g. tin and subjected to a catalytic step F3 with e.g. palladium.

The aqueous solution S4 can further comprise one or more of the following additives aiming at improving the global aesthetic appearance of the textile substrate and the speed of the oxidoreduction reaction:

- (a1) additives, such as e.g. ammonium chloride or ammonia, which act as accelerators for accelerating the speed of the redox reaction; and/or

- (a2) additives, such as e.g. ammonium chloride or boric acid, which act as brighteners for improving the aesthetic appearance of the metallized textile substrate; and/or

- (a3) additives, such as stranger ions e.g. lead ions (e.g. lead sulfate) or cadmium ions, which act as stabilizers for stabilizing the redox reaction.

The aqueous solution S4 should further comprise as additives a complexing or chelating agent such as citric acid or sodium citrate dihydrate or EDTA for increasing the yield of the redox reaction.

The textile substrate T is immersed into said solution S4 comprising an amount of 5 g/l to 30 g/l, e.g. 15 g/l, of nickel sulfate; an amount of 5 g/l to 20 g/l, e.g. 10 g/l, of sodium hypophosphite; an amount of 10 g/l to 30 g/l, e.g. 20 g/l, of ammonium chloride; an amount of 5 g/l to 15 g/l, e.g. 8 g/l, of citric acid; an amount of 0.004 g/l to 0.01 g/l, e.g. 0.0073 g/l, of lead sulfate, and an amount of 5 g/l to 20 g/l, e.g. 10 g/l, of sodium hydroxide at a temperature between 40°C and 50°C, preferably between 43°C and 46°C, at a pH value between 8 and 10, preferably between 8.5 and 9, and for a residence time between 1 minute and 20 minutes, preferably between 5 minutes and 10 minutes.

When the textile substrate T leaves the pair of cylinders C6C, it has ended the metallization treatment by chemical route F4 and is ready to be fed to the tank V6 to be subjected to a rinsing step.

The tank V6 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C41 and C43, is arranged above the second row of cylinders, which comprises e.g. cylinders C42 and

C44.

Said first and second row of cylinders are immersed in a solution Sris contained in tank V6, except for cylinder C41. The textile substrate T, by means of the pair of cylinders C6C, reaches cylinder C41 and then gets into solution Sris contained in tank V6. The textile substrate T remains immersed in tank V6 thanks to the presence of cylinders C42-C44 building a path (up and down) inside tank V6 having a length of e.g. 4 meters to 8 meters. Then, the textile substrate T leaves tank V6 and reaches the pair of cylinders V7 and then tank V7. The pairs of cylinders C6C and C7C are motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pairs of cylinders C6C and C7C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C7C is also to squeeze the textile substrate so as to remove from it the excess of solution Sris. The solution Sris is a demineralized water bath at a temperature of 20°C to 30°C, preferably 25°C.

After said metallization step by chemical route F4, a finishing step can be preferably carried out. The finishing step can be carried out in the same apparatus or alternatively outside it by means of e.g. a common tentering machine.

The finishing step, not shown in the figures, aims at finishing the metal layer deposited onto the textile substrate for improving the characteristics of the textile substrate itself.

In one embodiment of said finishing step, the finishing treatment is carried out by heating, preferably using an infrared device. The operating temperature is as high as possible considering the type of fiber to be treated, for instance in the case of a textile substrate comprising polyester fibers the operating temperature should be below 130°C, e.g. about 110°C. Heating reproduces in some manner a metal annealing process. Heating gives the metal layer deposited onto the textile substrate a higher harness and a lower brittleness.

After the metallization step by chemical route F4, after the rinsing step in a solution Sn _S and preferably after the finishing step, in the process of the present invention the textile substrate T is subjected to a metallization step by galvanic (or electrochemical) route, in short F5. Galvanic metallization F5 allows to deposit a final metal layer by means of electrolytic techniques. Galvanic metallization F5 allows to strongly reduce the brittleness of the metal deposit, increase fabric conductivity, increase shielding properties and uniform the color of the deposit and the final aesthetic appearance of the textile substrate. The apparatus shown in Figure 1 B allows to deposit a metal film with a higher thickness without damaging the final feel of the textile substrate, therefore imparting properties which would otherwise (due to the need for a high weight percentage of metal) make the textile substrate harder. In the framework of the present invention, the wording "deposit/ing a metal film" can also mean carrying out a metal coating or deposition with a metal e.g. zinc, silver, gold, copper, nickel, lead, cobalt and iron, or with a binary alloy such as e.g. nickel/cobalt, or with a ternary alloy such as e.g. white bronze.

After said optional finishing step carried after leaving the tank V6, a metallization step by galvanic or electrochemical route (referred to for shortness' sake as F5) is carried out in tank V7. In the metallization step by galvanic or electrochemical route, for instance, the textile substrate T, rinsed and optionally finished as referred to above and coming from the tank V6, is fed through the pair of cylinders C7C to the pair of cylinders C8C, which in its turn feed the textile substrate T to a tank V7._The tank V7 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C45, C48, C51 , is arranged above the second row of cylinders, which comprises e.g. cylinders C46, C47, C49 and C50. Said first and second row of cylinders are immersed in a solution S5 contained in tank V7. The textile substrate T, by means of the pair of cylinders C8C, gets down to the first upper cylinder C45 and into solution S5 contained in tank V7, then going farther as far as the first lower cylinder C46 and then up to the second lower cylinder C47.

Then, the textile substrate T reaches the second upper cylinder C48 and temporarily leaves the solution S5 contained in tank V7 and is fed to the pair of cylinders. C9C. The textile substrate T, by means of the pair of cylinders C9C, gets down perpendicularly to the third lower cylinder C49 and again into solution S5 contained in tank V7, then going farther as far as the fourth lower cylinder C50 and then up to the third and last upper cylinder C51. The textile substrate T definitely leaves the solution S5 contained in tank V7 and is fed to the pair of cylinders C10C. The textile substrate T remains immersed in tank V7 thanks to the presence of cylinders C45- C51 building a path inside tank V7 having a length of e.g. 4 meters to 8 meters.

Then, the textile substrate T leaves tank V7 and reaches the pair of cylinders C10C. The pairs of cylinders C8C.C9C and C10C are motorized and can be made of steel. The function of the pairs of cylinders C8C, C9C and C10C is to maintain the textile substrate T under continuous traction only and to provide the textile substrate T with cathodic current (length of fabric immersed in the bath varying from 4 to 10 meters, width of fabric in the loom 1.5 m to 1.8 m, applied voltage 2 to 12 volt, e.g. 4 to 8 volt; maximum amperage on the whole immersed surface 10 A to 300 A, e.g. 50 A to 100 A; preferably values are 0.10 A/dm ² to 0.80 A/dm ² , e.g. 0.20 A/dm ² , 0.30 A/dm ² , 0.40 A/dm ² , 0.50 A/dm ² , 0.60 A/dm ² , 0.70 A/dm ² .

The metallization step by galvanic or electrochemical route F5 involves the deposition and formation of a metal coating or film onto the textile substrate T coming from a pre-treatment step F1 , an activation step F2, a catalytic step F3 and a metallization step F4. In one embodiment of said metallization step by galvanic or electrochemical route, the metallization treatment by galvanic or electrochemical route F5 involves the use of a water soluble salt of the metal or metals making up the alloys to be deposited onto the textile substrate. Said salts can release the metal ions once dissolved into the aqueous solution S5.

In one embodiment, the textile substrate T coming from said metallization step F4, said rinsing step and said optional finishing step, is contacted with an aqueous solution S5 comprising e.g. a water soluble salt of the metal to be deposited, preferably said metal ions are chosen from the group comprising or alternatively consisting of nickel, copper, zinc, silver, cobalt, lead, iron and gold, or binary alloys such as nickel/cobalt, or ternary alloys such as white bronze.

The cathodic current present on the textile substrate T is supplied by the pairs of cylinders C8C C9C C10C. For a textile substrate having a length (fabric immersed in the bath) varying from 4 to 10 meters and width in the loom of 1.5 m to 1.8 m, the applied voltage is 2 to 12 volt, e.g. 4 to 8 volt, the maximum amperage on the whole immersed surface is 10 A to 300 A, e.g. 50 A to 100 A; preferable values are 0.10 A/dm ² to 0.80 A/dm ² , e.g. 0.20 A/dm ² , 0.30 A/dm ² , 0.40 A/dm ² , 0.50 A/dm ² , 0.60 A/dm ² , 0.70 A/dm ² .

The cathodic current together with the anodic current supplied by anodes A1-A8 present in tank V7 (Figure 2) can start the formation of a metal coating or the deposition of a metal film, and thus the anodic current can provide the electrons required to turn the metal ions with positive oxidation number (e.g. Ni ²⁺ or Cu ²⁺ or ^A a ¹⁺ or Zn ²⁺ ) to a metal with zero oxidation number (nickel or copper or metallic silver or metallic zinc) directly onto the fibers of the textile substrate previously activated with e.g. tin, subjected to a catalytic step F3 with palladium, to a metallization step F4 and to an optional finishing step.

The aqueous solution S5 can further comprise one or more additives aiming at improving the global aesthetic appearance of the textile substrate, the reaction speed and the effectiveness of said step F5. For instance, an additive that can be used is sodium saccharine, which acts as a grain refiner and as a brightener.

The textile substrate T is immersed into said solution S5 comprising e.g. 220 g/l of nickel sulfate, 80 g/l of nickel chloride, 50 g/l of boric acid and 0.25 g/l of sodium saccharine, at a temperature between 20°C and 60°C, preferably between 23°C and 46°C, at a pH value between 4 and 7, preferably between 4.2 and 4.6, and for a residence time between 1 minute and 14 minutes, preferably between 4 minutes and 10 minutes.

When the textile substrate T leaves the pair of cylinders C10C, it has ended the metallization treatment by galvanic or electrochemical route F5 and is ready to be fed to the tank V8 to be subjected to a rinsing step.

The tank V8 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C52 and C54, is arranged above the second row of cylinders, which comprises e.g. cylinders C53 and

C55.

Said first and second row of cylinders are immersed in a solution Snsi contained in tank V8, except for cylinder C52. The textile substrate T, by means of the pair of cylinders C10C, reaches cylinder C52 and then gets into solution Snsi contained in tank V8. The textile substrate T remains immersed in tank V8 thanks to the presence of cylinders C53-C55 building a path inside tank V8 having a length of e.g. 4 meters to 8 meters. Then, the textile substrate T leaves tank V8 and reaches the pair of cylinders C11C. The pair of cylinders C11C is motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pair of cylinders C11C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C11C is also to squeeze the textile substrate so as to remove from it the excess of solution Snsi. The solution Snsi can be a bath of mineralized water at a temperature of 20°C to 30°C, preferably 25°C, or a bath containing an acid or basic component which is able to neutralize acid or alkaline pH values from the previous metallization step by galvanic or electrochemical route F5, at a temperature between 20°C and 30°C, preferably 25°C.

When the textile substrate T leaves the pair of cylinders C11C, it has ended the rinsing treatment and is ready to be fed to the tank V9 to be subjected to another rinsing step.

The tank V9 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C56 and C58, is arranged above the second row of cylinders, which comprises e.g. cylinders C57 and C59.

Said first and second row of cylinders are immersed in a solution Sn _S 2 contained in tank V9, except for cylinder C56. The textile substrate T, by means of the pair of cylinders C11C, reaches cylinder C56 and then gets into solution Sris2 contained in tank V9. The textile substrate T remains immersed in tank V9 thanks to the presence of cylinders C57-C59 building a path inside tank V9 having a length of e.g. 4 meters to 8 meters. Then, the textile substrate T leaves tank V9 and reaches the pair of cylinders C12C. The pair of cylinders C12C is motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pair of cylinders C12C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C12C is also to squeeze the textile substrate so as to remove from it the excess of solution ris2. The solution Sn _S 2 can be a bath of mineralized water at a temperature of 20°C to 30°C, preferably 25°C, or a bath containing an acid or basic component which is able to neutralize acid or alkaline pH values from the previous metallization step by galvanic or electrochemical route F5, at a temperature between 20°C and 30°C, preferably 25°C.

When the textile substrate T leaves the pair of cylinders C12C, it has ended the rinsing treatment and is ready to be fed to the tank V10 to be subjected to a last rinsing step.

The tank V10 comprises a first upper row of cylinders and a second lower row of cylinders, which are spaced apart from each other for a distance e.g. of 1 meter to 2 meters. The first row of cylinders, which comprises e.g. cylinders C60 and C62, is arranged above the second row of cylinders, which comprises e.g. cylinders C61 and C63.

Said first and second row of cylinders are immersed in a solution Sn _S contained in tank V10, except for cylinder C60. The textile substrate T, by means of the pair of cylinders C12C, reaches cylinder C60 and then gets into solution Sris contained in tank V10. The textile substrate T remains immersed in tank V10 thanks to the presence of cylinders C61-C63 building a path inside tank V10 having a length of e.g. 4 meters to 8 meters. Then, the textile substrate T leaves tank V10 and reaches the pair of cylinders C13C. The pair of cylinders C13C is motorized and can be made of steel coated with a rubber resistant to chemicals. The function of the pair of cylinders C13C is to maintain the textile substrate T under continuous pressure/traction. The function of the pair of cylinders C13C is also to squeeze the textile substrate so as to remove from it the excess of solution S _r i _S . The solution Sris is a demineralized water bath at a temperature of 20°C to 30°C, preferably 25°C.

When the textile substrate T leaves the pair of cylinders C13C, it has ended the final rinsing treatment and is ready to be rolled as a piece and then subjected to a last drying step carried out outside in traditional textile drying equipment, such as e.g. a tentering machine.

An embodiment of the present invention is the following: first the chemical pre-treatment F1.1 , which can be carried out on a textile substrate T1 comprising e.g. synthetic fibers such as e.g. polyester or nylon and/or natural fibers of vegetable origin such as e.g. cotton or linen. The textile substrate T1 can be treated with an acid solution S1 comprising water and a mineral acid such as e.g. 37% hydrochloric acid at a concentration of 5 to 20 ml/liter of solution, preferably 10 to 15 ml/liter of solution. Solution S1 (T1) has a pH value of 0.5 to 2.5, preferably 1 to 1.5. The textile substrate T1 can be treated for a time of 1 to 30 minutes, preferably of 10 to 15 minutes, at a temperature of 20°C to 40°C, preferably of 30°C to 35°C, under continuous and gradual stirring.

Said chemical treatment F1.1 can be carried out in an equipment or apparatus as shown in Figure 1A, tank V1 , or also in an apparatus for processing open width fabrics such as e.g. a padder. At the same time as the chemical treatment F1.1 , the textile substrate T1 is subjected to a physical/mechanical treatment F1.2, as described above. Then, the textile substrate T1 is subjected to an activation step F2, a catalytic step F3, a metallization step F4 by chemical route and optionally a finishing step, a metallization step by galvanic or electrochemical route F5, as described above, with intermediate rinsing steps.

In still another embodiment of the present invention, the chemical treatment F1.1 can be carried out on a textile substrate T2 comprising e.g. natural fibers of proteic origin such as e.g. wool or silk. The textile substrate T2 can be treated with an alkaline solution comprising water and a mineral base S1 (T2) such as e.g. 30% sodium hydroxide at a concentration of 5 to 20 ml/liter of solution, preferably 10 to 15 ml/liter of solution. Solution S1 (T2) has a pH value of 9 to 13, preferably 10 to 12. The textile substrate T2 can be treated for a time of 1 to 30 minutes, preferably of 5 to 15 minutes, at a temperature of 20°C to 40°C, preferably of 30°C to 35°C, under continuous and gradual stirring.

Said chemical treatment F1.1 can be carried out in an outside equipment for processing open width fabrics such as e.g. a padder. At the same time as the chemical treatment F1.1 , the textile substrate T2 is subjected to a physical/mechanical treatment F1.2, as described above.

Then, the textile substrate T3 is subjected to an activation step F2, a catalytic step F3, a metallization step by chemical route F4 and optionally a finishing step, a metallization step by galvanic or electrochemical route F5 and an optional finishing step, as described above, with intermediate rinsing steps. Then, the textile substrate T1 or T2 is subjected to an activation step F2 involving a treatment with a solution S2 consisting of 10 ml/l of 37% hydrochloric acid and 7 g/l of tin chloride, at a temperature between 20°C and 30°C, preferably between 23°C and 28°C, at a pH value between 1 and 2, preferably between 1 and 1.5, and for a residence time between 5 and 12 minutes, preferably between 9 minutes and 10 minutes.

Said activation step F2 can be carried out in an apparatus such as the one shown in Figure 1A, tank V1.

Then, after a rinsing step in a solution Sn _S , the textile substrate T1 or T2 is subjected to a catalytic step F3 in which the textile substrate T1 or T2 is subjected to a treatment with a solution S3 consisting of 2 ml/l of 37% hydrochloric acid and 0.1 g/l of palladium chloride, at a temperature between 20°C and 30°C, preferably between 23°C and 28°C, at a pH value between 2 and 3, preferably between 2 and 2.5, and for a residence time between 3 and 7 minutes, preferably between 4 and 5 minutes.

Said catalytic step F3 can be carried out in an apparatus such as the one shown in Figure 1 A, tank V3.

Then, after a rinsing step in a solution S _r i _S , the textile substrate T1 or T2 is subjected to a metallization step by chemical route F5 involving a treatment time between 1 minute and 20 minutes, preferably between 5 minutes and 15 minutes, at a pH value of 8 to 11 , preferably from 8 to 9 and at an operating temperature of 20°C to 50°C, preferably of 40°C to 45°C under continuous and gradual stirring since during the oxidoreduction reaction between the reducing agent (sodium hypophosphite) and the metal ion occurs on the surface of the fabric hydrogen gas which, if not removed prevents (by creating insulating areas between the bath and the fabric surface similar to an "air bubble") the reaction itself from correctly taking place.

In a preferred embodiment, the solution S4 comprises a nickel salt such as nickel sulfate at a concentration of 5 to 20 g/l, preferably of 13 to 16 g/l. The reducing agent present in the solution S4 is chosen among hypophosphites, such as e.g. a sodium hypophosphite, and is used at a concentration of 5 to 11 g/l, preferably of 9 to 10 g/l. Advantageously, a weight ratio of nickel sulfate to sodium hypophosphite of 1.5:1 gives rise to a stable and lasting reaction without modifying the textile substrate and leaving it soft. Moreover, also a complexing agent for the nickel ion such as e.g. citric acid can further be used, in an amount of 5 to 10 g/l, preferably of 7 to 9 g/l. Moreover, also an accelerator/brightener such as e.g. ammonium chloride or boric acid can further be used, at a concentration of 10 to 30 g/l, preferably of 15 to 25 g/l. Also a stabilizer such as e.g. lead sulfate can be used, at a concentration of 0.005 to 0.01g/l.

As an alternative, copper can be deposited instead of the aforesaid nickel in the metallization step F4 as follows. The textile substrate T1 or T2 is contacted with a solution S4 containing copper sulfate at a concentration of 5 g/l to 10g/I, preferably of 7 g/l to 9 g/l, nickel sulfate at a concentration of 0.1 g/l to 1 g/l, preferably of 0.4 g/l to 0.8 g/l (nickel sulfate, e.g. 1 g/l, is useful for starting the reaction). The treatment time is of 1 minute to 20 minutes, preferably of 5 minutes to 15 minutes, at a pH value of 8 to 11 , preferably of 8.5 to 9, and at an operating temperature of 40°C to 60°C, preferably of 45°C to 55°C, under continuous and gradual stirring.

The reducing agent used can be sodium hypophosphite at a concentration of 5 g/l to 20g/l, preferably of 10 g/l to 15g/l. The complexing agent for the nickel ion used is citric acid in an amount of 10 g/l to 22 g/l, preferably of 18 g/l to 21 g/l. Moreover, also an accelerator/brightener such as e.g. boric acid is used, at a concentration of 10 to 30 g/l, preferably of 25 to 30 g/l. The stabilizer used is lead sulfate at a concentration of 0.005 g/l to 0.01 g/l. Said metallization treatment with nickel or copper can be carried out in an apparatus such as the one shown in Figure 1A, F4 tank V5.

After the metallization step by chemical route F4, the rinsing step in a solution Sn _S and preferably the finishing step, the textile substrate T1 or T2 is subjected to a treatment of galvanic or electrochemical metallization.

In one embodiment, a bath or a solution S5 is used comprising a copper sulfate in an amount of 80 g/l to 200 g/l, preferably of 90 g/l to 110 g/l, sulphuric acid in an amount of 100 g/l to 300 g/l, preferably of 150 g/l to 250 g/l. The operating temperature is of 15°C to 30°C, preferably 25°C, and the voltage applied is of 2 volts to 8 volts, advantageously of 2 volts to 6 volts. Said solution S5 enables to obtain a metallized fabric with a large amount of deposited copper having a fine grain allowing to maintain optimal tactile and softness properties.

In another embodiment, a bath or a solution S5 is used comprising a zinc sulfate in an amount of 100 g/l to 300 g/l, preferably of 200 g/l to 250 g/l, aluminum sulfate in an amount of 50 g/l to 200 g/l, preferably of 100 g/l to 150 g/l. The operating temperature is of 15°C to 30°C, preferably 25°C, and the voltage applied is of 2 volts to 8 volts, advantageously of 2 volts to 6 volts. Said solution S5 enables to obtain a metallized fabric with a large amount of deposited zinc having a fine grain allowing to maintain optimal tactile and softness properties.

In another embodiment, a bath or a solution S5 is used comprising nickel chloride in an amount of 50 g/l to 150 g/l, preferably of 80 g/l to 100 g/l, hydrochloric acid in an amount of 100 g/l to 300 g/l, preferably of 150 g/l to 250 g/l. The operating temperature is of 15°C to 30°C, preferably 25°C, and the voltage applied is of 2 volts to 8 volts, advantageously of 4 volts to 6 volts. Said solution S5 enables to obtain a metallized fabric with a large amount of deposited nickel having a fine grain allowing to maintain optimal tactile and softness properties, see Figure 1 B, F5 tank V7.

Then, after the metallization step by galvanic or electrochemical route F5, the textile substrate T1 or T2 is subjected to a rinsing treatment in a solution Sn _S i, see Figure 1 B tank V8.

In one embodiment, said solution Snsi consists of: 50 g/l of sodium bicarbonate with an operating temperature of 20°C to 30°C, preferably 25°C.

In another embodiment, said solution Snsi consists of demineralized water with an operating temperature of 20°C to 30°C, preferably 25°C.

Then, after said rinsing step, the textile substrate T1 or T2 is subjected to another rinsing treatment in a solution Sris2, see Figure 1 B tank V9.

In one embodiment, said solution Sn _S 2 consists of: 50 g/l of boric acid with an operating temperature of 20°C to 30°C, preferably 25°C.

In another embodiment, said solution Sn _S 2 consists of demineralized water with an operating temperature of 20°C to 30°C, preferably 25°C.

Then, a rinsing step is carried out in a solution Sn _S , see Figure 1 B tank V10. An object of the present invention is an apparatus for preparing metallized textile substrates, such as woven fabrics, non-woven fabrics and knitted fabrics, made of natural fibers of proteic or vegetable origin, artificial and synthetic fibers, as described above.

The apparatus, as schematically shown in Figures 1 , 1A, 1 B and 2, comprises: (i) at least six containers or tanks V1-V6 arranged in series and having different size one from the other so as to carry out the activation step F2, the catalytic step F3 and the metallization step by chemical route F4 (Figure 1 and 1 A); (i) at least four containers or tanks V7-V10 arranged in series and having different size one from the other so as to carry out the metallization step by galvanic route F5 (Figure 1 and 1 B); (iii) mechanical means for moving the fabric forward; (iv) mechanical means for enabling traction (allowing the textile substrate to be constantly tensioned); (v) mechanical means for enabling circulation, movement and heating of the chemical baths or solutions S2-S5, Sris, Srisl and Sris2 used, and (vi) mechanical means for allowing the metallized substrate to be dried and directly rewound as a finished piece, and mechanical means for re-demineralizing the rinsing solutions Sris, Srisl and Sris2.

In one embodiment, each of the ten tanks arranged in series represents a specific step for the fabric. The first tank V1 carries out an activation F2 of the fabric T and has a propylene structure resistant to the acid compounds it contains (contained solution S2). All the tanks V1 to V10 are made of polypropylene. The second tank V2 (contained solution Sn _S ) carries out a rinsing of the textile substrate for removing the excess of solution S2 from the first tank, and also this tank V2 is made of synthetic material. The third tank V3 (containing solution S3) carries out the chemical catalytic treatment (referred to above as F3), and also this tank V3 is made of polypropylene. The fourth tank V4 (contained solution Sn _S ) carries out another rinsing of the textile substrate coming from said third tank V3 where the catalyzation treatment took place. The fifth tank (containing solution S4) carries out F4 one of the main treatments of the whole process, i.e. the chemical metallization of the fabric. Also tank V5 is made of a propylene-based structure. The sixth tank V6 (contained solution S _r i _S ) carries out another rinsing. The seventh tank V7 (containing solution S5) is apt to carry out the last treatment, i.e. the galvanic or electrochemical metallization, F5. The last three tanks V8 (contained solution S _r i _S i), V9 (contained solution S _S 2) and V10 (contained solution Sn _S ) are apt to carry out final rinsing steps.

The whole apparatus is moved by means of a system of belts/chains connected to one another by transmission to a motor, e.g. a 3 kW motor. The motion transmission system is mounted to the sides of the machine and develops along the whole length thereof, transmitting motion to thirteen pairs of cylinders previously referred to as C1C, C2C, C3C, C4C, C5C, C6C, C7C, C8C, C9C, C10C, C11C, C12C and C13C. Each pair is located just upstream from the tank outlet, except for pair C1C, C8C and C9C. The pairs of cylinders C1C, C2C, C3C, C4C, C5C, C6C, C7C, C11C, C12C and C13C consist of a lower traction cylinder and an upper squeezing cylinder, as a matter of fact these pairs of cylinders include a piston acting upon the upper cylinders-. One of the main functions of these pairs of cylinders is to maintain the fabric under constant pressure/traction. Both cylinders of each pair have a core that can be made of steel, and are coated with rubber. The rubber coating is useful both for improving friction and for avoiding the direct contact steel/acids. The squeezing cylinder can be heated so as to provide the fabric with a higher molecular "relaxation" and therefore promote penetration of the chemical reagents. The pairs of cylinders are located just upstream from the tank outlet so as to allow the fabric to be squeezed and therefore recover the liquid of the solution which the textile substrate T is still impregnated with, thus saving on processing costs. The pairs of cylinders described above have a spring mechanism or a pneumatic system which can adjust the pressure imparted by the squeezing cylinder, which is useful in case very light or very heavy fabrics are treated. The pairs of cylinders C8C, C9C and C10C are motorized and can be made of steel; their function is to maintain the textile substrate T only under continuous traction and to provide the textile substrate T with cathodic current. The cylinders C1 to C63 are idle, i.e. they can freely rotate and thus provide the sliding fabric a friction that is almost zero. These idle cylinders have several functions. One of the function is to allow an all-in-all free choice of the residence time of the fabric in the various baths, simply using more or less passages/returns in the latter, but their main and crucial function exploits the large number of returns in the metallization tank, which never allows to "certify" the fabric since the latter during the whole process is subjected to changes of direction which break and re-adapt deposits forming on the surface, thus eventually giving the fabric a much softer and non-metallic feel, which feature is obtained and enhanced also by the continuous traction provided also by the pairs of cylinders C1C to C13C. All idle cylinders are mounted onto removable structures which are useful both when the machine is loaded and if the immersion time has to be adjusted and therefore some pairs of idle cylinders have to be removed so as to reduce the residence time in the various solutions.

As far as the forward movement of the fabric is concerned, one of the major problems occurring most frequently in the textile industry is related to the surface tension, which causes folds on the fabric moving forward. In order to eliminate this problem, the machine is preferably equipped at every tank outlet with a special cylinder known as "dancer roll", which can remove folds formed on the fabric. In addition to this, in the machine speed is always the same both at the inlet and at the outlet, exploiting if required the "removability" of the structures onto which the cylinders are mounted so as to adjust treatment times without affecting the sliding speed of the fabric. Another crucial part of the apparatus is a handling mechanism for the baths, since some of them should be under constant stirring and all the baths should obviously be mixed when preparing the bath. To this purpose a side channel blower, connected to the tanks by means of a stirring coil which is arranged on the bottom thereof and is provided with uniform microholes allowing to effectively stir the bath. Beyond being handled, the baths should obviously also be heated, since the metallization reaction is more effective at certain temperatures. The heating method identified exploits electric resistors located on the tank bottom so that heat can be homogeneously distributed. The resistors used should anyhow be coated with Teflon or ceramic, since the chemical reactions of the first, third and fifth tank are reactions exploiting the electronegativity of the elements and the reagents might be deposited onto the resistors instead of the fabric. It was designed to use a power of about 36 kW for the resistors, together with a timed thermostat which, when the process is idle, maintains tank temperature in a steady state. A preferred part of the machine is related to the direct re-winding of the treated textile substrate T in a piece. As far as fabric re-winding is concerned, a winding truck was provided for, which winds up the fabric without tension thanks to a dancer roll connected to a potentiometer managing winding progress.

For a longer life of the various baths a filter pump can be used, which is connected to the various treatments and which thanks to a possibly continuous filtration maintains the bath clean and without foreign bodies or unreacted particles. The machine also includes a system of ventilating hoods so as to prevent aerosols and fumes from being diffused into the environment. The tank V7 is the one designed to carry out the metallization treatment by galvanic or electrochemical route (step F5). For the transmission of electric energy there is a mechanism which is able to transmit a correct current intensity to the fabric. The technical solution identified is obtained thanks to the pairs of cylinders C8C, C9C and C10C in a sliding contact with one another, which supply the textile fabric T with cathodic current. Conversely, as far as the transmission of anodic current is concerned, a structure located above the tank is used, from which titanium hooks containing anodes A1 to A8 are hung (Figure 2, tank V7). Anodes A1 to A8 are positioned vertically in the tank and are placed opposite the treated fabric.

The Applicant conducted a long research and development activity which led to the implementation of an apparatus and of a process for preparing a metallized textile substrate and to the metallized substrate forming the object of the present invention. Moreover, the Applicant tested 5 samples of metallized textile substrates as referred to below:

i) Sample No. 1 (C(i)): basis substrate: polyester 100% plain weave weight 100 g/sqm.

Metallization (as described and/or claimed in the process in steps F1 to F5): first layer nickel (Ni), second layer nickel (Ni) resulting weight 185 g/sqm.

ii) Sample No. 2 (C(ii)): basis substrate: polyester 100% satin weave weight 95 g/sqm.

Metallization (as described and/or claimed in the process in steps F1 to F5): first layer nickel (Ni), second layer copper (Cu) resulting weight 160 g/sqm.

iii) Sample No. 3 (C(iii)): basis substrate: nylon 100% plain weave weight 100 g/sqm.

Metallization (as described and/or claimed in the process in steps F1 to F5): first layer nickel (Ni), second layer nickel (Ni) resulting weight 175 g/sqm.

iv) Sample No. 4 (C(iv)): basis substrate: wool 100% plain weave weight 120 g/sqm.

Metallization (as described and/or claimed in the process in steps F1 to F5): first layer nickel (Ni), second layer copper (Cu) resulting weight 210 g/sqm.

v) Sample No. 5 (C(v)): basis substrate: polyester 70% viscose 30% satin weave weight 80 g/sqm.

Metallization (as described and/or claimed in the process in steps F1 to F5): first layer nickel (Ni), second layer copper (Cu) resulting weight 140 g/sqm.

The 5 samples of metallized textile samples C(i)-C(v) were prepared using the process of the present invention by means of an apparatus as shown in Figures 1 , 1A and 1 B, comprising: - A pre-treatment step (for shortness' sake F1) consisting in a chemical treatment (referred to for shortness' sake as F1.1) together with a physical/mechanical treatment (referred to for shortness' sake as F1.2). Said chemical F1.1 and physical/mechanical F1.2 treatment are carried out together. Said treatments F1.1 and F1.2 can act upon the molecular structure of the fibers present in the textile substrates in order to create amorphous areas (microholes and/or openings) on the surface of the fibers themselves so as to promote the penetration of the following treatment baths or solutions provided for in the following process steps. Said chemical treatment F1.1 makes use of a solution consisting of 37% hydrochloric acid at a concentration of 10 ml/l and demineralized water with a pH value of 0.5-1.5 (specifically for samples No. 1 , 2, 3 and 5).

Said chemical treatment F1.1 makes use of a solution consisting of sodium hydroxide at a concentration of 1-5 ml/l and demineralized water with a pH value of 8-10 (specifically for sample No. 4).

- An activation step (for shortness' sake F2) consisting in an activation treatment activating the surface of the textile substrates for the following process steps. Said treatment F2 makes use of a solution consisting of 37% hydrochloric acid at a concentration of 7 ml/l, stannous chloride 7 g/l with a pH value of 0.5-1 (specifically for samples No. 1 , 2, 3, 4, 5).

- A catalytic step (for shortness' sake F3) consisting in a catalyzation treatment so as to catalyze the surface of the textile substrate for the following steps F4 and F5 of the process. Said treatment F3 makes use of a solution consisting of 37% hydrochloric acid at a concentration of 0.5 ml/l, palladium chloride 0.2 g/l with a pH value of 1.5-2 (specifically for samples No. 1 , 2, 3, 4, 5).

- A metallization step (for shortness' sake F4) by chemical route consisting in the deposit and formation of a metal coating or film onto the textile substrate. Said treatment F4 makes use of a solution consisting of nickel chloride, sodium hypophosphite, ammonium chloride, tribasic sodium citrate, 24.5% ammonia with a pH value of 8.5-9 (specifically, sample No. 1 , 2, 3, 4, 5: nickel chloride 1.5 g/l, sodium hypophosphite 10 g/l, ammonium chloride 20 g/l, tribasic sodium citrate 16 g/l, pH 8.75).

- A metallization step by galvanic or electrochemical route (for shortness' sake F5). The galvanic metallization F5 allows to deposit a final metal layer by means of electrolytic techniques. Said treatment F5 makes use of a solution consisting of salt/s of the metal to be deposited, buffering agents, additives (specifically, sample No. 1 , 3: nickel chloride 70 g/l, nickel sulfate 200 g/l, boric acid 40 g/l, saccharine 1 g/l, pH 3.5-4; samples No. 2, 4, 5: copper sulfate 200 g/l, sulphuric acid 70 g/l, 37% hydrochloric acid 2 ml/l pH 0.1-1).

- A drying step carried out outside, in traditional textile drying equipment, such as a tentering machine.

The 5 samples of metallized textile substrates C(i)-C(v) were tested with the following methods M1-M3:

M1) Test method for determining the heat resistance of reflecting insulating materials.

M2) Test method for determining the surface resistivity of conductive insulating materials.

M3) Test method for determining the level of electromagnetic shielding to frequency ranges between 100 MHz and 2.5 GHz of metallized textile substrates.

M1) Test method for determining the heat resistance of reflecting insulating materials Sample description

A tested sample consists of a reflecting insulating material, surface mass density 300 g/m ² , nominal size 1200 ^χ 1500 mm and thickness 12 mm, made up of: - 1-2x outer layers of metallized fabric (samples used as described above); - 2x layers of needle-loomed polyester TNT wadding; - 6x layers of expanded polyethylene. The board is sealed on the edges by means of an aluminized tape.

Test apparatus

The test was carried out with a hot box with guard ring, having a measuring area of 1.52 m x 1.52 m and surfaces with an emissivity of 0.93.

Sample conditioning

Before being subjected to the test, the sample is subjected in a climatic chamber to a temperature of 70°C and relative humidity of 90 % for a period of 1-28 days, and then conditioned at a temperature of (23 ± 2)°C and relative humidity of (50 ± 20)%.

Test execution

The sample was installed in the test apparatus vertically, in the middle of a rectangular opening made in a support board made of expanded polystyrene EPS. The opening was closed with 2x outer walls made of multilayer material (thickness 20 mm) so as to create 2x air gaps with a thickness of 25 mm between the walls and the sample. The sample is maintained in its position by means of 14x spacers made of EPS (size 20 ^χ 20 mm, thickness 25 mm). In the cold box the heat exchange occurs by forced convection, the flow being directed upwards and parallel to the surface of the sample, whereas in the measuring chamber it occurs by forced convection, the flow being directed downwards and parallel to the surface of the sample. For detecting temperatures the following sensors are applied to each side of the apparatus: - 9x for measuring air temperature; - 9x on the surface of the screen of the apparatus; - 9x on the inner surface of the multilayer board; - 5x on the surfaces of the sample being tested; - 7x on the surface of the EPS support board. Data are processed so as to determine the value of heat resistance experimentally.

Test duration was of 104 hours. The heat resistance of the sample R was measured with the unit of measure "square meters K/W".

All the 5 samples tested gave very interesting results, with a value of heat conductance in the range of 0.004 W/mK to 0.06 W/mK (heat resistance = 1/heat conductance).

M2) Test method for determining the surface resistivity of conductive insulating materials

Sample description

The tested sample consists of a conductive textile substrate, mass 50/300 g/m ² , size 1000 ^χ 1000 mm and thickness 1/20 mm, made up of: - 1x layer of metallized fabric (samples used as described above).

Test apparatus (voltmeter model mastech digital multimeter MS 8268)

The test is carried out using a source of 24 volt/0.4 ampere direct current, with positive and negative terminals connected and two copper parallelepipeds with a base of 1 square cm, spaced of 1 cm with a plastic structure. The two copper terminals are connected to a voltmeter, which detects the voltage (volt) flowing between the two terminals in which a current of 0.4 ampere is induced, as described above. According to the formula ohm = volt/ampere, the experimental measure of surface resistivity is obtained.

Sample conditioning

Before being subjected to the test, the sample is conditioned at a temperature of (23 ± 2)°C and relative humidity of (50 ± 20)%.

Test execution

The sample thus conditioned is placed on a non-conductive smooth surface. A variable number of measures are carried out (e.g. 10-30 measures) on the sample surfaces, measures are collected and averaged.

Test duration was of 1 hour. The surface resistivity of the sample was measured with the unit of measure ohm/cm.

All the 5 samples tested gave very interesting results, with a value of surface resistivity in the range of 10 megaohm to 300 megaohm; in particular, sample 1 =50-250 megaohm/square cm, sample 2=10-25 megaohm/square cm, sample 3=150-250 megaohm, sample 4=10-100 megaohm and sample 5=10-25 megaohm.

M3) Test method for determining the level of electromagnetic shielding to frequency ranges between 100 MHz and 2.5 GHz of metallized textile substrates

Sample description

The tested sample consists of a conductive textile substrate, mass 50/300 g/m ² , size 1000 ^χ 1000 mm and thickness 1/20 mm, made up of: - 1x layer of metallized fabric (samples used as described above).

Test apparatus

The test was carried out with a signal generator with a band of 9 KHz to 2.5 GHz, a spectrum analyzer 20 HZ to 2.9 GHz and a shielded box sized 9x6x6 meters.

Sample conditioning

Before being subjected to the test, the sample is conditioned at a temperature of (23 ± 2)°C and relative humidity of (50 ± 20)%.

Test execution

The conditioned sample is placed so as to close an opening in the shielded box opposite the signal generator placed inside the box. The spectrum analyzer detects the frequencies at the outlet of the shielded box, from which the ability to attenuate the electromagnetic fields generated by the generator can be inferred.

The test duration was of about 1.5 hours and time is a variable function of the number of measures to be obtained.

The attenuation of the electromagnetic fields was measured with a unit of measure Db (Decibel).

All the 5 samples tested gave very interesting results, with a value in the range of reduction of magnetic field expressed in Decibel of 20% to 90%. Moreover, the Applicant made an IR emission evaluation of the samples of fabric. "Substrate polyester 100% Ni- LC(nickel layer conductive) - sample 1 (C(i))".

Instrumental tests were carried out for calculating the emissivity of said fabric. Fabric characterization:

The instrument used is a thermal imaging camera AVIO TVS-700 equipped with non-cooled microbolometric sensor of 320x240 pixel (thermal resolution 0.05°C, spatial resolution 1.4 mrad). Measured made by a second- level CICPND technician as per standard UNI EN ISO 9712. Emissivity was determined in the wavelength range between 8 and 14 microns using the comparison method with targets having a known emissivity whose certified value is 0.95. Detected room temperature 24°C. Measured reflected temperature consistent with the one detected inside the oven.

The pictures show the reference white target with 0.95 emissivity; in order to obtain the emissivity of the fabric, an area with a comparable temperature with the one of the target are should be selected on the thermographic images and its emissivity should change until the same temperature as the reference is obtained. In the images below (Figures 3-6) the fabric sample 1 "Polyester 100% Ni-LC(nickel layer conductive)" is the one with the lighter color (the second one from the left) with an IR emissivity of 0.28. In the images below the fabric sample 1 Polyester 100% Ni-LC(nickel layer conductive) is the one with the lighter color (the first one from the left) with an IR emissivity in two different fabric portions of 0.28/0.31.

The tests carried out on the fabric sample 1 "Polyester 100% Ni-LC(nickel layer conductive)" point out a low IR emissivity (values vary between 0 and 1). Emissivity varies from one fabric area to the other but always remains within low emissivity ranges (0.28-0.31). For sample no. 3, a value of 0.15 to 0.35 was obtained, whereas for samples no. 2, 4 and 5 a value of 0.05 to 0.35 was obtained.