FR2997101A1 - Producing textile, comprises printing textile medium using printing paste containing gold salts having mass concentration, where printing step is performed by screen printing using a single screen frame - Google Patents

Abstract

The method comprises printing a textile medium using a printing paste containing gold salts having mass concentration of greater than 5-50 g/l and gold cations (Au3+ or Au+); and a fixing step. The printing paste contains 1-10 g/l of metal elements other than gold. The fixing step is carried out at 100-120[deg] C for 5-45 minutes. The printing step is performed by screen printing using a single screen frame that is varied gradually from an opening part of a gauze in one or more directions. The method further comprises coloring step performed with traditional textile dyes. Independent claims are included for: (1) textile printing paste; and (2) textile produced by the method.

Description

The invention relates to a process for producing a variable color-effect textile containing gold or at least one alloy containing gold in the form of particles, a printing paste for textile and a variable color effect textile containing gold or at least one alloy containing gold in the form of particles. Gold in the form of particles loses its usual metallic appearance and absorbs light very strongly. This is the plasmon effect at the origin of an intense red coloring, known for a long time and used for example in certain stained glasses of cathedrals, or crystal objects. When this feature is implemented on different textiles, including silk fabrics having different types of armor, a range of color varies depending on: the size of the particles, the composition of the alloy, the concentration of particles in the fabric, or depending on the type of fabric and in particular the weight of the fabric. The application W000 / 46438 describes a process for manufacturing a textile containing particles of at least one transition metal, in particular gold, in two steps: a first step of fixing a nucleating agent on the textile fiber ( reducing agent), and a second immersion step in a weakly concentrated transition metal solution (0.1% to 0.001% w / v). This process makes it possible to obtain different colorings depending on the size and spacing of the particles, the transition metal used and the characteristics of the textile.

The work of Victoria University of Wellington also describes the use of a reducing agent (sodium tricitrate) to form in situ silver nanoparticles on the surface of wool in which sodium tricitrate allows the binding of nanoparticles silver to amino acids of keratin present in wool fibers (FM Kelly et al., ACS Appl., Mater.

Interfaces, 2011.3, 1083-192.

These two processes are "dyeing" type processes (complete immersion of the fabric in the solutions) which make it possible to produce homogeneous stains on the entire surface of the textile. We have now found a printing process using a printing paste containing gold salts which makes it possible to obtain localized colorings (for example, by frame printing, ink jet, etc.). .) and to realize all types of localized and precise patterns, wherein said textile is brought into contact with all the reagents or additives in the same step.

This new process also makes it possible to obtain an iridescent effect on the printed textile (color varying according to the angle of observation) or, in particular, by using a suitable frame etching, to obtain a color fade effect. (a very gradual and continuous gradient from purple to yellow) in one step and using a single frame.

These advantageous effects can not be obtained by carrying out the process described in application W000 / 46438. Indeed, in addition to the coloring power of the metal particles described in the prior art, an original optical effect has now been demonstrated, namely the obtaining of an iridescent effect and / or a color intensity which can be modulated according to the gold content in the fabric as well as the viewing angle and / or the type of illumination. Advantageously, this coloration can be obtained by printing a textile support, and not by immersion in a solution of metal salts or in a suspension of metal nanoparticles. According to the invention, the metal particles responsible for the coloration and the optical effects are generated by a manufacturing method comprising at least one step of printing the textile support, without immersing said textile support in a metal solution, and at least one step fixing, for example by exposure of the textile to water vapor. Without wishing to link the invention to a theory, it can be hypothesised that the iridescence observed on the textile according to the invention comes from the presence of particles containing gold, or an alloy containing gold, of different sizes, namely small gold particles having the plasmon-like absorption characteristics and larger and / or agglomerated particles whose properties are similar to the metallic behavior of gold (weaker and displaced absorption) partial reflection of light).

Advantageously, it has been observed that this optical effect does not modify the feel of the textile and does not require any modification of the existing printing process, for example a method of the fixed / washed type with acid dyes. Indeed, it is possible to print on the same textile patterns made with traditional textile dyes and patterns made with the printing paste according to the invention without modification of the conventional method of printing on textile (printing, fixing, washing) Until now, the only means of achieving iridescent effects on a textile were: - the laminating of a multilayer film, holographic etc., - the deposition of layers of metals, metal alloys or oxides of metals, optionally in multilayer, - the deposition by gel sol of multilayers of metal oxides, - the use of photonic crystal fibers or Bragg mirror (to reflect certain specific colors), - the printing of iridescent pigments, - the coating by synthetic opals (inverse or not), or - warp and weft effects with colored threads (taffeta). According to the invention, the iridescent effect is advantageously obtained without losing the intrinsic textile qualities, which is not the case when using a laminated film or a pigment printing (effects due to the resin and / or the pigments ). In addition, the textile remains entirely in original material (silk, etc.), which is not the case if we add photonic crystal fibers, if we deposit iridescent pigments incorporated in a resin by printing or if a coating is made with a synthetic opal. In addition, this effect can be obtained directly on an existing production machine and, in particular, in a single pass. The invention therefore relates to a method of manufacturing a variable coloring effect textile, said textile comprising a textile support and gold particles or alloy containing gold, comprising at least one step of printing a textile support using a printing paste containing gold salts of mass concentration Au3 + or Au + cations greater than 1g / I, and at least one step fixing. Preferably, said printing paste contains gold salts with a mass concentration of Au3 + or Au + cations of between 5 and 50 g / l. By "textile support" is meant a textile containing no gold particles or an alloy containing gold. The textile support may be chosen, for example, from fabrics, nonwovens, meshes or braids. In particular, the textile support may be chosen, for example, from silk, cotton, cashmere, polyamide or any other textile which preferably comprises free amine or hydroxyl functions. By "particle" is meant an assembly comprising at least one crystallite of gold or an alloy containing gold. The average particle size is, for example, between 5 and 1000 nm, in particular between 50 and 500 nm. The size of the particles is therefore variable depending on whether they are formed of a single crystallite, or an agglomeration of crystallites (higher average size). The size of the crystallites can be deduced from X-ray diffraction measurements from the Scherrer formula, as described further below. The textile printing paste containing gold salts having a mass concentration of Au 3 + or Au + cations of greater than 1 g / l, preferably of between 5 and 50 g / l, is also an object of the invention. It may also contain a mixture of metal cations comprising gold in a proportion of 1 to 10 g / l of metallic elements other than gold. Said metallic elements other than gold may be chosen, for example, from silver, platinum, palladium or another noble metal. As gold salts, it is possible, for example, to use chlorides, bromides or cyanides. To obtain alloy particles containing gold, it is possible to use, for example, gold chloride and silver nitrate or platinum chloride or else palladium chloride. Preferably, the fixing step is carried out at a temperature of the order of 100 to 120 ° C. The fixing step can have, for example, a duration of 5 to 45 min. The method according to the invention may also comprise a fixed textile washing step. According to a preferred embodiment, the manufacturing method thus comprises the following steps: the printing of the base textile with the aid of a printing paste containing gold salts of mass concentration in Au 3 + cations; Au + greater than 1g / I, especially between 5 and 50 g / I, - the fixing of the textile thus printed, and - the washing of the fixed textile. The printing paste according to the invention may contain water and various additives customary in the field of textile printing, such as a thickening composition containing, for example, a nonionic etherified polysaccharide such as guar, urea (is a hygroscopic product that has the function of attracting water to the surface of the fabric and promoting the development of particles), an antifoaming agent, a printing oil, a preservative, etc. Preferably, the printing paste, after mixing and homogenization, has a viscosity of from about 5 cP to 25000 cP, preferably of the order of 10 Pa.s ( 10000 cP). In the case of ink jet printing, the printing paste, after mixing and homogenization, preferably has a viscosity of between 0.005 Pa.s (5cp) and 0.015 Pa.s (15cp). By using the printing paste according to the invention, it is possible to control the amount of gold or alloy containing gold applied via the printing paste to the textile support.

Advantageously, the printing process according to the invention makes it possible to bring together, during one and the same step, the base fabric and all the reagents or additives, and to obtain localized colorations (for example, by printing to the frame, inkjet, etc.) as well as to realize all types of localized and precise patterns, or to obtain an iridescent effect (color varying according to the angle of observation). In addition, the method according to the invention also makes it possible to obtain an iridescent effect (color varying according to the angle of observation) also localized (thanks to printing) by implementing well-defined conditions (depending on the viscosity of the printing paste, the concentration of metal ions in the paste, etc.). The printing method according to the invention also makes it possible, in particular by using a suitable frame etching (possibility of varying the concentration of metal ions which passes through the frame within this same frame) to obtain a color fade effect (a very gradual and continuous gradient from purple to yellow) in a single step and using a single frame. Advantageously, the printing is thus performed by screen printing. In particular, it has been found that the use of the printing paste as defined above in the manufacturing method according to the invention makes it possible to obtain a gradient / fade of colors by screen printing in a single printing step. . Indeed, a continuous color fade between two distinct dyes on textile can be easily achieved by the technique of inkjet printing or by any other technique of digital coloring. On the contrary, the realization of this coloristic effect by printing techniques such as screen printing or gravure printing is much more complicated to implement both from a technical and financial point of view. Indeed, these techniques use "physical" printer forms (flat or rotating frames) that are at least equal to the number of colors or patterns that one wishes to print. In addition, the areas of overlap between the different colors are very often visible to the eye and unattractive.

According to the invention, gradually varying (by increasing or decreasing) the opening of the gauze of the screen printing frame, and thus the amount of printing paste deposited, in one or more directions, a gradient of this quantity is obtained. , which makes it possible to obtain a fade of colors.

This fade can be perfectly continuous and realized using a single frame and a single printing paste, and more in one pass. The subject of the invention is therefore also a process for manufacturing a variable coloring textile containing gold or at least one alloy containing gold in the form of particles, as defined above, comprising a step printing a textile support using a printing paste as defined above, said printing being performed by screen printing, in which a single screen-printing frame is used and the opening of the screen is gradually varied; the gauze of said frame in one or more directions.

Moreover, particular visual effects can be achieved by superimposing the printing of at least two printing pastes. Thus, for example, the superposition of two pastes having an Au3 + or Au + ion concentration of 40 g / I will make it possible to develop a color close to a base color prepared at 80 g / I of Au ion. These particular visual effects could not be obtained by the previously described dyeing processes. According to an advantageous aspect, the method according to the invention can also comprise, in addition, at least one staining step carried out with traditional textile dyes. Indeed, the method according to the invention is feasible under standard production conditions (printing, fixing wash), which allows to juxtapose within the same textile traditional colors (for example, using acid dyes .. .) and colors obtained by printing using a printing paste based on Au3 + or Au + ions or alloys containing them, according to the invention. Thus, it is possible to print on the same textile patterns made with traditional textile dyes and patterns made with the printing paste according to the invention without modification of the conventional textile printing process.

For example, a textile can be printed on a Lyonnaise printing table with a drawing comprising 10 colors, the colors 1 to 5 and 8 to 10 being obtained with traditional dyes and the colors 6 and 7 being obtained by the printing using an Au ion-based printing paste or alloys containing them. The colors can be printed one after the other, the colors obtained from the metal ions can be printed indifferently at the beginning, in the middle or at the end of the printing process without intervention on the support or modification of the usual process. .

The invention also relates to a textile with variable coloring effect, comprising a textile support and gold particles or a gold-containing alloy, obtainable by the method described above. In particular, the invention relates to a textile having a variable color effect, comprising a textile support and gold particles or a gold-containing alloy, wherein the gold or the alloy comprises gold is present in the form of particles of average size between 5 and 1000 nm, and at least 10% of said particles have a size is less than 50 nm. In particular, the average particle size is between 50 and 500 nm. Advantageously, at least 25% of the gold or alloy containing gold is present in the form of a particle of average size equal to or less than 50 nm, preferably equal to or less than 30 nm and at least 25% of the gold-containing alloy or alloy is present as a particle or agglomerate of particles of average size equal to or greater than 100 nm, preferably 300 nm or more. The variable coloring fabric according to the invention may advantageously have an iridescent coloration, as indicated above. By "particle" is meant an assembly comprising at least one gold crystallite or alloy containing gold.

The size of the particles is therefore variable depending on whether they are formed of a single crystallite or an agglomeration of crystallites (higher average size). The size of the crystallites can be deduced from X-ray diffraction measurements from the Scherrer formula. Scherrer's formula gives H = r ----> r = H.cos0. cos 9 with H = the width at half height (rad) 10 k = 0.89 = diameter of the crystallite (m) = wavelength of the X-rays (m) O = Bragg angle of the diffraction peak considered 15 if we consider that the broadening of the diffraction lines comes only from the finite extension of the coherent diffraction domains. However, this widening is also due to the existence of microdeformations of the network related to the presence of defects. The enlargements induced respectively by the size and by the microdeformations having different angular contributions, it can be shown that: cos 9 1 sin lB = + ke D 25 with p = the width at half height (rad) D = the size coherent diffraction domains = the rate of deformation. By plotting for the different diffraction lines the quantity pcos0 / 1 as a function of sinO / X, (Williamson-Hall diagram), we obtain a curve whose intersection with the y-axis is the inverse of the length the coherence of the crystalline domains, whereas the slope characterizes the rate of deformation. From the straight line equations thus obtained, it is possible to deduce the size of the coherent diffraction domains and the strain rate for each sample. In particular, the average size of the gold-containing or gold-containing crystallites deduced from X-ray diffraction measurements may be between 40 nm and 200 nm. Preferably, the concentration of gold or alloy containing gold in the fabric is of the order of 0.2 to 20 g / m 2, in particular of the order of 0.5 to 5 g. / m2. The alloy containing gold may contain, in addition, at least one metal selected from silver, platinum and palladium, preferably at 1% by weight.

The textile support may be, for example, silk, cotton, cashmere, polyamide or any other textile which preferably comprises free amine or hydroxyl functions. Preferably, the textile support is silk, which may be chosen, for example from twill, satin, pongee, jacquard fabric or any silk-based fabric. By "silk-based fabric" is meant a fabric having between 20 and 100% silk. The textile according to the invention has a coloration which varies according to the angle of observation. In particular, a variation of the LE color parameter of greater than 20%, in particular greater than 40%, can be observed by reflectance (ie the amount of energy re-emitted with respect to the quantity of energy received). between two different angles of observation taken between -60 ° and + 70 ° .AE is defined as a measure of difference between two colors, according to the formula established by the International Commission on Illumination (CIE) in 1976: 11E * = \ ALI. - L2) 2 + (ai - a2) 2 (bi b2) 2 in which Li * ai * bi * are the colorimetric coordinates of the L * a * b * system standardized by CIE of the first color to be compared, and L2 * a2 * b2 those of the second. As indicated above, the textile according to the invention may exhibit an iridescent coloration. Advantageously, the coloration of the textile according to the invention has a high fastness with respect to water, acidic sweat and alkaline sweat, as defined according to ISO 105-E01 and ISO 105- E04, in particular equal to 5 on the gray scale. The coloration of the textile according to the invention advantageously has a fastness with respect to friction, as defined according to ISO 105X12 standards, in particular equal to or greater than 4/5 for disgorging on the gray scale. and equal to 5 for degradation on the gray scale. The coloring of the textile according to the invention also has a high fastness with regard to artificial light, as defined according to ISO 105-B02, part B02, in particular equal to or greater than a degradation of the standard wool N ° 7 (of scale of the blues) of 4/5 according to the scale of the gray ones. The invention also relates to a textile as defined above, the color of which has a continuous color fade.

By "continuous color fade", it is meant that the areas of overlap between the different colors are not visible to the invention therefore allows, in particular, to obtain the following advantageous effects: - colorations that may be different depending on types of textiles for the same printing paste; different dyes for the same printing paste on a textile by varying the quantity deposited on the textile; different dyes for the same printing paste on a textile by varying the concentration of metal salts or the composition of metal salts on the same textile; a continuous color fade made using a single screen printing frame and a single printing paste, in a single pass; - a superimposition effect and color variation obtained by rematage printing and degraded / melted, - colorations made with traditional textile dyes and patterns made with the printing paste according to the invention on the same textile. Finally, an advantageous property of the textile according to the invention is to have an antifungal effect. The following examples illustrate, without limitation, the invention. An "Au x 1" type sample is defined as that obtained by a conventionally used gold / citrate synthesis, as described, for example, in J. Turkevitch, PC Stevenson, J. Hillier, The Faraday Society, 11, 55 -75 (1951) with a concentration of (NaAuC14) of 2.76 × 10 -4 M. An "Au x 100" sample thus corresponds to a gold salt concentration of 0.0276 M. The same calculation is carried out for the concentrations indicated in the examples which follow. EXAMPLE 1 Preparation of an Aux 100 Printing Paste for Textile Printing 100 ml of printing paste were prepared in the following manner: 1 g of NaAuCl 2 gold chloride, 2H 2 O were dissolved in 25 mL of water and 75 g of "Guar thickener + auxiliaries" preparation (thickener used in production for the production of master colors in acid dyes) with an optimum viscosity 28 Pa.s (28000 cP).

The formula for 1 kg of this preparation is as follows: 50 g urea, 5 g antifoam (aliphatic oil with emulsifier), 20 g oil imprint (hydrocarbons containing a nonionic emulsifier), 6 g of biocide, 125 g of guar, 794 g cold water. The paste is mixed slowly to make it as homogeneous as possible and has a viscosity of the order of 10 Pa.s (10000 cP).

Example 2: Preparation of an AuAg (95/5) x 100 printing paste for textile printing AuAg (95/5) means a mixture with 95 mol% of NaAuCl4 and 5 mol% of AgNO3. printing paste in the following manner: 0.95 g of NaAuCl 2 gold chloride, 2H 2 O and 22.75 mg of silver nitrate of formula AgNO 3 are dissolved in 25 ml of water and 75 g of Guar thickener + auxiliary products "as defined in Example 1. The paste is mixed slowly to make it as homogeneous as possible and has a viscosity of the order of 10 Pa.s (10000 cP). Example 3: Production of a colored tissue based on an Au x 100 printing paste The paste prepared in Example 1 is printed on a Twill-type piece of silk. The term "Twill" refers to the textile made with twill weave which is characterized by the presence of oblique ribs on the place and on the back. This printing is done by screen printing: 4 consecutive scraping of the print paste on the silk is carried out through a frame (M72 gauze), using a doctor blade, and then allowed to dry on a printing table. The colors are then fixed thanks to the passage of the printed silk in a continuous vaporizer (103 ° C, saturated steam, treatment time: 45 minutes). The fixing is carried out under the conditions of production of fixing bristles printed with acid dyes. The silk is then washed in the production line. This is a continuous wash off. The washing conditions correspond to the washing production conditions of silk printed with acid dyes (without fixer). The fabrics thus printed exhibit an intense coloration in the violets.

Figure 1 shows the absorption spectrum of the gold particles. The spectrum shows a fairly broad absorption band at about 550 nm which shows that the blue / green is absorbed. So we have a fabric that appears red / purple.

EXAMPLE 4 Production of a Colored Tissue Based on an AuAg (95/5) x 100 Printing Paste The procedure is the same as in Example 3 except that the dough is used. prepared in example 2. The printed fabrics thus have a very intense red-pink coloring. Indeed, FIG. 2 shows that the absorption spectrum of these AuAg particles has a slightly finer absorption band than Au particles alone for the same concentration. This results in a more "pure", red color.

EXAMPLE 5 Printing on Silk Satin The procedure is the same as in Examples 3 (Aux 100 printing paste) and 4 (AuAg (95/5) x 100 printing paste), but on silk satin. The term "silk satin" refers to silk textile having a shiny, flat face and a matte face. The shiny side results from the particular construction which consists in having on this face of the fabric long floats of warp or weft threads. The absorption spectra of the tissues thus obtained are shown in FIG.

EXAMPLE 6 Printing on a Silk Jacquard Fabric The procedure is the same as in Examples 3 (Aux 100 printing paste) and 4 (AuAg (95/5) x 100 printing paste), but on a jacquard fabric. The term "jacquard" refers to a fabric woven on a jacquard loom, forming patterns and thereby producing reversible fabrics. The absorption spectra of the tissues thus obtained are shown in FIG. 4.

EXAMPLE 7 Printing on Silk Natté The procedure is the same as in Examples 3 (Aux 100 printing paste) and 4 (AuAg (95/5) x 100 printing paste), but on silk braided. The "braided" is a textile derived from plain weave.

It is obtained by stacking several son, either warp or weft, so that a braid equal in number of warp threads rises to pass the same number of weft son; which gives a square braiding effect. This results in a heavy tissue whose weight can be between 150 and 200g / m2.

The absorption spectra of the tissues thus obtained are shown in FIG. 5. Example 8: Printing on Colored Backgrounds The procedure is the same as in Examples 3 (Aux 100 printing paste) and 4 (paste). type AuAg (95/5) x 100), but on twill of different colors such as blue, orange, purple, brown, black, green, etc. We then obtain colors that vary according to the background color: fuchsia on a dark blue background, yellow on a dark green and black background, orange 20 on a brown background for example. EXAMPLE 9 Production of a Printing Paste At x 400 for Textile Printing 100 ml of printing paste are prepared: 4 g of NaAuCl 2 gold chloride, 2H 2 O are dissolved in 25 ml of water and 75 g Preparation compound "Guar thickener + auxiliary products" as defined in Example 1. The paste is mixed slowly to make it as homogeneous as possible and has a viscosity of the order of 10 Pa.s (10000 cP). EXAMPLE 10 Production of Aux300 Printing Paste for Textile Printing The procedure is the same as for Example 9 except that 3 g of NaAuCl 4 gold chloride is used.

EXAMPLE 11 Production of an Au x 500 printing paste for textile printing The procedure is the same as for Example 9 except that 5 g of NaAuCl 4 gold chloride are used.

EXAMPLE 12 Production of an AuAd Printing Paste (95/5) x 400 for Textile Printing 100 ml of printing paste are prepared: 3.8 g of NaAuC14 gold chloride, 2H20 and 91 mg of nitrate AgNO3 silver are dissolved in 25 ml of water and 75 g of "Guar thickener + auxiliary products" as defined in Example 1. This paste is mixed slowly to make it as homogeneous as possible and has a viscosity of the order of 10 Pas (10000 cP).

EXAMPLE 13 Production of a Colored Tissue Based on an Aux400 Printing Paste The paste prepared according to Example 9 is printed on a piece of Twill-type silk. This printing is performed by screen printing: 4 consecutive scrapings of the print paste are performed on the silk through a frame (M72 gauze), using a doctor blade, and then allowed to dry on a printing table. The colors are then fixed thanks to the passage of the printed silk in a continuous vaporizer (103 ° C, saturated steam, treatment time: 45 minutes). The fixing is carried out under the conditions of production of fixing bristles printed with acid dyes. The silk is then washed in the production line. This is an offshore continuous wash in which the fabric is held flat, then passed through different wash baths containing detergents at different temperatures, and then dried directly at the wash outlet. The washing conditions correspond to the washing production conditions of silk printed with acid dyes (without fixer).

The silk thus dyed has an iridescent color. a) Measurement of color variation versus viewing angle Color variation versus viewing angle was measured using a spectrophotogoniometer. The reflectance curves are acquired at different pairs of illumination (111u) and observation (Mes) angles, for different orientations of the fabric (p): p 0 ° corresponds to a measurement in the direction of the fabric chain p 90 ° corresponds to a measurement in the direction of the weft of the fabric, and 15 p 450 corresponds to an oblique measurement. Two sources of illumination were retained: - D 65 for daylight: according to the lighting standard ISO 3664, the standard lighting D65 corresponds to the light of the sky without that of the sun. It is characterized by a very slight dominant of blue. - F2 (also called F, F02, FCW, FCF, CWF2), which represents the spectral quality of most fluorescent lamps (cold white), for neon-type lighting. The illumination is illuminated at 45 ° and the reflectance is measured for varying viewing angles around the fixed illumination source. In practice the observation is from -60 ° to + 70 °. The results obtained are shown respectively in FIGS. 6A, 6B and 6C for D65 and 7A, 7B and 7C for F2. The figures designated by the letter A relate to an observation angle p 0 °, those designated by the letter B relate to an observation angle p 450 and those designated by the letter C relate to an observation angle p 90 °.

The curves of the left part of each of FIGS. 6A, 6B, 6C, 7A, 7B and 7C give the abscissa value of a * and the ordinate the value of b *, that is to say the colorimetric coordinates of the different points whose value has been measured.

The histograms of the right-hand part of each of FIGS. 6A, 6B, 6C, 7A, 7B and 7C give the observation angle on the abscissa and the value of L * on the ordinate. The results show that there is a large variation in color depending on the angle of view. b) Size and Distribution of Metallic Particles (Statistical Study) FIGS. 8A, 8B, 9A and 9B show photos taken using a scanning electron microscope for an Aux400 printing paste.

In FIGS. 8A and 8B, the size of the gold particles present on a colored fabric whose production is described above is observed. Note the presence of gold particles heterogeneous in size, namely particles of the order of 1 to 2 μm mixed with small particles of the order of 100 nm. Figure 9A shows that the metal particles are heterogeneously dispersed along the silk fibers and agglomerates of particles are seen in Figure 9B. A statistical study of the particle size was made from the photos of Figures 8A and 9A. Each particle was measured to obtain a histogram of the number of particles depending on their size. Figs. 10A and 10B show the histograms respectively corresponding to the photos of Figs. 8A and 9A (shown in reduced size in the right corner of Figs. 10A and 10B). It is observed that the majority of the particles have an average size of the order of 200 to 300 nm, with a distribution between 100 nm and 900 nm. (c) Metal Particle Size (X-Ray Diffraction) Based on Diffractograms of Four Silk Tissue Samples Printed with AuAg (95/5) x 300 Printing Pastes, AuAg (95/5) x 500, Au x 400 and Au x 300 shown respectively in Figures 11, 12, 13 and 14, the values of p and O were deduced for each of the 4 lines of each sample, which are reported in Table 1 below. . Table 1 AuAg (95/5) x AuAg (95/5) x Au x 400 Au x 300 300 500 Streak 1 20 (°) 38.04992 38.26716 38.15018 38.06663 0 (°) 19.02496 19 , 13358 19.07509 19.033315 p (°) 0.21859 0.18507 0.19889 0.24306 (3 (rad) 0.003815115 0.003230081 0.003471285 0.004242197 Line 2 20 (°) 44.26652 44,45034 44,35008 44,31665 0 (°) 22,13326 22,22517 22,17504 22,158325 f3 (0) 0,32455 0,25356 0,25926 0,33885 13 (rad) 0,005664466 0, 004425457 0.004524941 0.005914048 Line 3 20 (°) 64.43706 64.65431 64.52062 64.5039 0 (°) 32.21853 32.327155 32.26031 32.25195 p (°) 0.35406 0, 27832 0.33862 0.36036 [3 (rad) 0.006179513 0.0048576 0.005910034 0.006289468 Radius 4 20 (°) 77.45516 77.63899 77.48859 77.53872 0 (°) 38.72758 38 , 819495 38.744295 38.76936 f3 (°) 0.51895 0.37012 0.3896 0.43569 [3 (rad) 0.009057386 0.006459813 0.006799803 0.007604225 The values of f3cos0A, and sin0A, reported in Table 2 below were used to plot the Williamson - Hall diagram presented in Figure 15. linear regression lines from the experimental points.

Table 2 AuAg (95/5) x Stripe 1 Stripe 2 Stripe 3 Stripe 4,300 Pcos0a (A-1) 0.002342027 0.003407177 0.003394803 0.004588268 sine / X (Â-1) 0.21167534 0.244650679 0.346201244 0.404245619 AuAg (95/5) x Ray 1 Ray 2 Ray 3 Ray 4 500 pcos0 / 1 (A-1) 0.001981585 0.002660172 0.002665398 0.003268182 Sinea (A-1) 0, 21283874 0,24561525 0,34724214 0,407057757 Au x 400 Stripe 1 Stripe 2 Stripe 3 Stripe 4 13cos0nt. (A-1) 0.002130312 0.002720944 0.003245268 0.003443821 sine / A, (A-1) 0.212212364 0.245089227 0.346601747 0.40393986 At x 300 Rays 1 Rays 2 Rays 3 Rays 4 OcosOnt , (A-1) 0.002604073 0.003556667 0.003453938 0.003849876 sinea (A-1) 0.211764855 0.244913792 0.346521623 0.406614907 Equations of straight lines thus obtained, we deduce the size of the 10 domains diffraction pattern and strain rate for each sample (Table 3). Table 3 AuAg (95/5) x AuAg (95/5) x Au x 400 Au x 300 300 500 1 / D (A-1) 0.0007 0.0011 0.001 0.002 D (Â) 1428.571429 909.0909091 1000 500 D (nm) 142.9 nm 90.9 nm 100 nm 50 nm E 0.90% 0.52% 0.63% 0.46% The results show that the average particle size in the measured samples is about 50 to 100 nm. d) Absorption Figure 16 shows the peak absorption of the silk sample prepared above. The absorption spectrum is characteristic of a plasmon absorption due to gold-based particles with a fairly large size dispersion. EXAMPLE 14 Production of AuAq (95/5) x 400 Color-Based Printing Dye Fabric The procedure is the same as in Example 13 except that the dough printing prepared in Example 12 (AuAg (95/5) x 400). The resulting fabrics also show a color change depending on the viewing angle. This effect is highlighted in Figs. 17A, 17B and 17C (daylight type lighting - D65) as well as 18A, 18B and 18C (neon-type F2 lighting). Figure 16 shows the peak absorption of a tissue sample of Example 15 as compared to a sample obtained in Example 13. The silver allows a refinement of the peak of absorption of the sample which is translated by a purer color (red) in the end. The absorption spectrum is characteristic of a gold-based plasmon absorption with small particles. EXAMPLE 15: Printing in rematch (superposition of printing layers) Au x 400 and AuAg (95/5) x 400 print pastes were prepared as described in Examples 9 and 12. Aux printing paste 400 is printed as described in Example 13 on Twill type silk. Once the silk is dry, we print AuAg printing paste (95/5) x 400 straddling the printing of Au x 400 paste and virgin silk. The silk is then fixed in a continuous vaporizer (103 ° C., saturated steam, treatment time = 45 minutes) and washed in the production line as well. This is a continuous wash off as well.

The fabric thus printed has effects of color variations as described in Examples 13 and 14. In addition to these effects, it has other interesting effects: a change of color at the location of the superposition, due to a addition of particulate concentration during rematching. At the place of superimposition the coloring is lighter and tends towards yellow. This phenomenon is shown schematically in Figure19. Example 16: Performing a gradient / color fade by screen printing in a single printing step An Au x 500 printing paste is prepared as described in Example 11. This printing paste is printed on Twill silk screen printing through a printing frame whose gauze opening is gradually increased or decreased in one or more directions, i.e. a gradient frame is used which allows more or less printing paste depending on the places in one pass. The resulting fabric is fixed and washed as described in the previous examples. A perfectly continuous color fade from violet to yellow is obtained. The results show that, with the same printing paste, different colorations are obtained by varying the quantity deposited per unit area. Example 17: Artificial light fastness test of the colors obtained by printing / fixing / washing of gold-based paste Printed and fixed-washed silk twill samples described in Example 13 but with Au x 300, AuAg (95/5) x 400 and AuAg (99/1) x 400 were exposed to artificial light according to ISO 105-B02, part B02, such that degradation of grade 7 of the blue scale corresponds to a 4/5 degradation of the gray scale (which corresponds to the tests carried out on upholstery fabrics). The results show that no discolouration is observed which indicates very good fastness. EXAMPLE 18 Water, Acid Sweat and Alkaline Sweat Fade Tests of Fixing Washed Gold Wash Colors These tests were performed on the fixed-washed printed silk twill samples. described in Example 13 but with Au x 300, AuAg (95/5) x 400 and AuAg (99/1) x 400. The tests were carried out according to ISO 105-E01, part E01 / E03, part E03 / E04 and part E04. The colored tissue samples are soaked for 1 / 2h in water or in solutions simulating acidic or alkaline sweats. The samples are then sandwiched between a white silk fabric and a standard white cotton fabric, and then placed between two plexiglass plates. All the "sandwiches" thus produced are placed in an oven whose temperature is set at 37 ° C for 4 hours. The different layers are then separated and the disbudding of the dye on the 2 control tissues is evaluated using the gray scale. The results show that there is no disgorging of the gold stains on the two control tissues, which indicates that the water and acid / alkaline sweat fastnesses obtained on these three samples are very good. EXAMPLE 19 Friction Solidity Test (Dry, Wet) Crockmeter of the Colors Obtained by Printing / Fixing / Washing of Gold-based Paste These tests were carried out on a fixed-washed printed Twill-type silk sample. described in Example 13 but with Au x 300. The tests were performed according to ISO 105X12. The principle is as follows: rubbing back and forth (10 going back and forth at a defined pressure) of a white cotton control on the printed sample. The stains are then evaluated with the gray scale.

The results show that, for wet and dry friction, good strength is obtained, namely a rating of 4/5 of the gray scale. EXAMPLE 20 Dry Clean (Dry Chemical) Powder Strength Test of Printed / Fused / Washed Gold Based Paste Colors These tests were performed on a fixed-washed printed silk twill sample described in the example. 13 but with Aux 300 and a fixed-washed printed silk satin sample described in Example 5 but with AuAg (95/5) x 300. Samples undergo one and three dry cleanings. The degradation of the perchlorethylene-treated samples is evaluated by comparing the appearance with the untreated sample on a scale of 1 to 5, with 5 being the best score. After 1 dry cleaning, we get a score of 4/5, which indicates a very good strength. After 3 dry cleanings, a score of 4/5 is also obtained, which confirms a very good color fastness. EXAMPLE 21 Production of an AuAq (95/5) x 300 printing paste for textile printing 100 ml of print paste are prepared: 2.85 g of NaAlCl.sub.4, 2.H.sub.2 O and 68.25 g of gold chloride. mg of silver nitrate AgNO3 are dissolved in 25 ml of water and 75 g of "Guar thickener + auxiliary products" as defined in Example 1. This paste is mixed slowly to make it as homogeneous as possible and has a viscosity of the order of 10 cP (10,000 cP). Example 22: Fonqistatic control The tests were carried out according to the AFNOR NFX41517 standard. The method is used to evaluate the behavior of the analyzed support in a fungal attack.

A qualitative test consisting of a visual examination of mold growth was performed on two rectangular samples (2 x 2.5 cm) of silk fabric printed with Au x 300 (Example 10) and AuAg ( 95/5) x 300 (Example 21) in comparison with a piece of unprinted silk of the same size. The test protocol is as follows: a) Preparation of the inoculum: The spores of the specific fungus are used as a mixture in the form of inoculum: 200 ml of distilled water containing a non-toxic wetting agent are prepared, which it is sterilized for 15 min at 120 ° C. To a few ml of the cooled solution are poured into culture tubes, prepared between 14 days and one month previously. The surface of the mycelium is scraped with a sterile inoculator to dislodge the spores without damaging the medium. The contents of each tube are then sterile filtered and stirred to obtain a suspension. The microbiological activity is controlled by inoculating samples of the same support, bare. B) Preparation of the test medium: A test medium containing: Ammonium nitrate NH4NO3: 3 g MgSO4 magnesium sulfate, 7 H0: 0.5 g Potassium chloride KCl: 0.25 g Phosphate KH2PO4 monopotassium: 1 g Agar band: 20 g Distilled water: 1000 ml The salts are dissolved in the order listed in a sufficient quantity of water, then the agar is added and the mixture is made up to 1000 ml. . The pH is adjusted if necessary with potassium hydroxide solution. It is sterilized for 15 minutes at 120 ° C. c) Performing the test To prevent impregnation of the samples by the test medium during the fungal exposure, they are placed in the vials on an isolation support. These supports are sterilized in an autoclave for 20 minutes at 120 ° C in a large amount of water. We do a test to check that they have no fungistatic properties. Samples are not sterilized. 150 ml of the test medium solution is poured into each sterilized vial and allowed to cool on a flat surface. When the solution has gelled, two strips of sterilized isolation mounts are placed in each vial, the samples are deposited on the isolation mounts. For each vial, 3 ml of the inoculum solution is taken with a sterile pipette and poured onto each sample, then the vials are incubated in a black oven at 30 ° C ± 1 ° C with 95% + 15%. 5% relative humidity for 14 days. d) Results Two visual examinations were performed at 7 days, then 14 days during the test, to evaluate the presence of spores or mycelial growth on the surface of the samples. If, at the end of the test, an incipient invasion is detectable on the surface of a sample, the support is considered unprotected. The results are shown in Table 4 below. Table 4 Sample No. 7 Day Reading 14 Day Reading Printed: Aux 300 3 2 - 2 2 - 2 Mycelium Printed Mycelium: AuAg 4 1 - 1 1 - 1 ( 95/5) x300 mycelium mycelium unprinted 5 2 - 2 2 - 2 mycelium mycelium Reading of the plates: - 0: no development - 1: trace of fungal development - 2: slight development (10 to 30% of the surface of the mycelium) specimen) - 3: average development (30 to 60% of the surface of the test specimen) - 4: high development (> 60% of the test specimen surface) For the sample printed with a printing paste of Aux 300 type, a result similar to that of the unprinted silk is observed. There is indeed a slight fungal development, mycelium, that is to say the vegetative part of the fungi. There is no fungistatic effect of gold on silk. For the sample printed with an AuAg (95/5) x 300 printing paste, only traces of mycelium are observed, which shows antifungal effect.

Claims (24)

REVENDICATIONS1. A process for producing a variable coloring textile, said textile comprising a textile support and gold particles or a gold-containing alloy, characterized in that it comprises at least one step of printing said textile support using a printing paste containing gold salts of mass concentration Au3 + or Au + cations greater than 1g / I, and at least one fixing step. 2. Process according to claim 1, characterized in that the printing paste contains gold salts with a mass concentration of Au3 + or Au + cations of between 5 and 50 g / l. 3. Method according to one of claims 1 or 2, characterized in that said printing paste contains a mixture of metal cations comprising gold at a rate of 1 to 10 g / I of metallic elements other than gold . 15 4. Method according to any one of claims 1 to 3, characterized in that said metal elements are selected from silver, platinum and palladium. 5. Method according to any one of claims 1 to 4, characterized in that the fixing step is carried out at a temperature of the order of 100 to 120 ° C. 6. Method according to any one of claims 1 to 5, characterized in that the fixing step is carried out for a period of 5 to 45 min. 7. Method according to any one of claims 1 to 6, characterized in that the textile support is selected from silk, a silk-based fabric, cotton, cashmere, polyamide or any other textile that includes, preferably, free amine or hydroxyl functions. 8. Method according to any one of claims 1 to 7, characterized in that the printing is performed by screen printing. 30 9. A method according to claim 8, wherein the printing is performed by screen printing, characterized in that a single screen printing frame is used and the opening of the gauze of said frame is gradually varied in one or several directions. 10. Method according to any one of claims 1 to 9, characterized in that it comprises, in addition, at least one staining step performed with traditional textile dyes. 11. Textile printing paste containing gold salts of mass concentration in Au3 + or Au + cations greater than 1g / 1. 12. Printing paste according to claim 11, characterized in that it contains gold salts of mass concentration in Au3 + or Au + cations of between 5 and 50 g / l. 13. Printing paste according to one of claims 11 or 12, characterized in that it contains a mixture of metal cations comprising gold at a rate of 1 to 10 g / I of metal elements other than the gold. 14. Textile with variable coloring effect, comprising a textile support and gold particles or a gold-containing alloy, obtainable by the method according to any one of claims 1 to 10, containing a concentration of gold or alloy containing gold in the range of 0.2 to 20 g / m 2. Textile according to Claim 14, characterized in that the gold or alloy comprising gold is present in the form of particles comprising at least one gold or alloy crystallite comprising gold having a average size between 40 and 200 nm. Textile according to claim 15, characterized in that the concentration of the gold-containing alloy or gold-containing material in the fabric is of the order of 0.5 to 5 g / m2. 17. Textile according to any one of claims 14 to 16, characterized in that the alloy containing gold contains at least 1% by weight of a metal selected from silver, platinum, palladium or another noble metal. 18. Textile according to any one of claims 14 to 17, characterized in that it is selected from a fabric, a nonwoven, a mesh or a braid. 19. Textile according to any one of claims 14 to 18, characterized in that the textile support is selected from silk, a silk-based fabric, cotton, cashmere, polyamide or any other textile which comprises, preferably, amine or free hydroxyl functions. 20. Textile according to any one of claims 14 to 19, characterized in that the textile support is a silk fabric selected from twill, satin and pongee. 21. Textile according to any one of claims 14 to 20, characterized in that its color varies depending on the angle of observation. 22. Textile according to any one of claims 14 to 21, characterized in that a variation of the color parameter LE greater than 20% can be observed by reflectance between two different angles of observation taken between -60 ° and + 70 °. 23. Textile according to any one of claims 14 to 22, characterized in that its coloration is iridescent or has a continuous color fade. 24. Textile according to any one of claims 14 to 23, characterized in that it has an antifungal property. 20