MXPA00001860A - Procedure for dyeing a textile material with indigo using indoxyl and system for exploiting this procedure - Google Patents

Abstract

The invention is directed to a procedure for dyeing a textile material with indigo, using indoxyl which comprises the stages of:pre-washing the F thread making it go through a pre-wash system composed of two or more tubs containing a pre-washing solution;dyeing subsequently the thread making it go through a tinting system composed of a series of eight tubs, containing each of them an indoxyl solution and during the passage from one tub to the other, the thread suffers oxidation due to air exposure converting indoxyl to indigo, that then dyes the thread by impregnation, the oxidation is done by means of air exposure so that, during the passage from the first tub to the eighth tub in succession, if a x value is given to the oxidation between the first and second tubs, it will be obtained successively the following values, oxidation value between the 1st and 2nd tubs=x, oxidation value between the 2nd and 3rd tubs=2x, oxidation value between the 3rd and 4th tubs=3x, oxidation value between the 4th and 5th tubs=4x, oxidation value between the 5th and 6th tubs=5x, oxidation value between the 6th and 7th tubs=6x, oxidation value between the 7th and 8th tubs=7x, oxidation value after the 8th tub=8x, washing and pre-drying the thread putting it through a washing and drying system comprising a series of tubs, the first tub containing water, the others acetic acid, and containing water, so that the pH in the last tub is of about 6 and 7 and, at the tub outlet, the thread is pre-dried passing through the rollers;preparing the indigo colorant over the thread passing through a priming system comprising a tub containing a mixture of resins in order to form a transparent film over the thread fibers;drying the thread passed it through a drying system composed of rollers;picking the warp thread rolling it on the reel.

Description

PROCEDURE TO DYE A TEXTILE MATERIAL WITH INDIGO USING INDOXYLUS AND SYSTEM TO EXPLOIT THE PROCEDURE DESCRIPTIVE MEMORY The present invention relates to a process for dyeing an indigo textile material using ndoxyl and the system for exploiting the process. By means of this method, an indigo-dyed textile yarn is produced from which a fabric called a denim fabric can subsequently be prepared for the production of articles such as denim trousers, for example. Indigo is one of the oldest known dyes and has been used for centuries to dye textiles such as cotton. EP-B-0 692 042 discloses a process for dyeing a textile fabric containing cellulose using indigo during which an aqueous solution of leucoindigo prepared by catalytic hydrogenation is used, the latter being converted to its pigment form by oxidation with air followed by its absorption into the textile genre. US-A-4 283 198 describes a continuous process for dyeing indigo cellulose fibers in which the fibers are passed through a series of soaking tanks containing a coloring solution comprising leucoindigo, sodium hydrosulfite and sodium hydroxide.

Patent application US-A-3 457 022 describes a process for dyeing cotton fibers with indigo in which the indigo is applied on the yarns at a temperature between 65 ° C and 80 ° C and the indigo is then applied at lower temperatures at 40 ° C. Denim trousers dyed with indigo have the disadvantage of fading. In recent years, there has even been a trend to wear bleached jeans and the industry developed procedures and systems to follow this trend, in which the discoloration of the textile material was emphasized and promoted by promoting the warp yarn discoloration. The method of use of dye aided the discoloration and the aging process. But all fashion is ephemeral and lasts only a certain time. Patent application EP 98630005.1 describes an indigo dyeing process during which a mason fabric is produced which is resistant to wear and discoloration. By means of this procedure, the indigo penetrates deeply into the thread. In procedures prior to this patent application, the yarn contained a white central core and only the outer part was dyed with indigo. EP 98630005.1, the white central core was much thinner. The object of the present invention is the production of a denim fabric which resists wear and discoloration and the yarn obtained is precisely dyed through to such a degree that the white central core is practically non-existent and has even disappeared.

By means of the process and the system according to the present invention, the penetration of the indigo by the yarn is achieved, by completely or virtually eliminating the inner white core and thus eliminating the aging of the textile material caused by the discoloration that it gave to the washing. Until now, one of the reasons for the failure of the indigo to penetrate precisely through the thread throughout has been its great molecule: H Indigo It is known, however, that the synthesis of indigo is obtained with oxidation of two indoxyl molecules according to the equation: ixtloxyl Hdoxyl H indigo H It is assumed that the indoxyl reacts according to its tautomeric ketonic formula.

By means of the process according to the present invention, the yarn to be dyed is impregnated with indoxyl and then oxidized in indoxyl in situ to obtain the indigo. Without wishing to be limited by any particular theory, it is assumed that the indoxyl molecule, which is smaller than the indigo molecule, penetrates the thread more deeply and thus the disappearance of the white nucleus is obtained due to the in situ oxidation of the indoxyl to give the indigo, which will be fixed on the thread through all its thickness. The method for dyeing a textile fabric according to the invention is described in claim 1. The system for exploiting the dyeing process is described in claim 8. By means of the method according to the invention, the operations carried out normally to dye the yarn with indigo blue are modified, by means of the inclusion of additional operations, both in the stage of the vats as well as the oxidation and preliminary mercerization stages, to help the absorption and impregnation capacity of the thread. During the oxidation process according to the invention, the first stage consists of very rapid exposures to the air at the beginning of the process than in the initial dye baths and the exposure period is subsequently progressively increased after each bath in order to help the penetration of the indoxilo to the thread and carry out the oxidation in situ.

The yarn is then treated with steam under specific conditions of temperature and pressure, before being washed and re-harvested. The second stage of the process consists of forming insulation around the yarn now dyed to make it firm to the wash and then it is ready for use. To achieve this, the yarn must first be made neutral by successive cycles through acid baths. The yarn is then dried completely and the indigo will be fixed permanently and will possess the required characteristics. As stated above, the yarn obtained by the processes known in the art is composed of a white central core, that is to say unstained, and an external part impregnated with indigo dye. By means of the process according to the invention, the central core is dyed precisely through indigo. In order that this invention may be better understood, reference is made to the accompanying figures in which: Figure 1 shows a schematic view of the prewash system used during the process according to the invention; Figure 2 shows a schematic view of an indoxyl staining system used during the process according to the invention; Figure 3 shows a schematic view of the washing and pre-drying system used during the process according to the invention; Figure 4 shows a schematic view of the sizing system used during the process according to the invention; Figure 5 shows a schematic system of the warp yarn drying and warping system according to the invention. The method according to the invention will now be described with reference to Figures 1 to 5 successively. According to this method, a prewash stage is first carried out by passing the yarn F coming from the supply roll on which it is wound through a prewash system (1) composed of two or several tanks ( 2) that contain a prewash solution (10, 15). The yarn is guided by the rollers (3) and (4) to the first tub (2) that contains the prewash solution and then, when leaving this solution, it passes between two squeezing rollers to remove excess liquid and then, guided by the roller (6), it is immersed again in the prewash solution. When leaving this bath, the thread passes between two squeezing rollers (7). Then, guided by the guide rollers (8) and (9), the thread is immersed in the prewash solution (15) contained in the second tank (2). The yarn travels through the second tub following a course identical to that followed through the first tub moving successively between two squeezing rollers (12), below the guide roller (11), then between the squeezing rollers (13). ). The prewash solution contains an absorbent product such as FINBIL (produced by the Bozzetto company) (commercial description), which is a fatty alcohol phosphoric acid ester derivative. It is used in the aqueous solution at a concentration of 5 to 8 g / liter. The prewash wash is used to impregnate the yarn to aid subsequent penetration by the indoxyl. After this prewash step, the yarn reaches the actual drying step, which is carried out in the drying system shown in Figure 2. The drying system (30) is composed of a series of 8 tanks (35) containing an indoxyl solution. The yarn F from the prewash system is guided by the guide roller (31) to the staining solution contained in the first tub (35), rotates around the roller (32) and leaves the bath to move between the first rollers of squeezed (34) and the first tub (35), rotates around the roller (33) and returns to the staining solution in the first tub, rotates around the second roller (32) of the first tub to then leave the bath, passes between the second set of squeezing rollers (34) of the first tub. Then, the thread passes around the roller (36). During the path between the second set of squeezing rollers (34) and the roller (36), the impregnated yarn is oxidized and the indigo that colors the yarn is formed. After rotating around the roller (36), the yarn moves to the dyeing solution obtained in the second tank, in which it follows the same course as in the first tank by means of the rollers (31), (32) and (34) of this second tank. At the outlet of the second bowl, the wire no longer rotates around a roller (36), as it did at the exit of the first bowl, but around two rollers (36) and a roller (37), so that the passage exposed to the air leaving the second tank will be twice as long as the passage when leaving the first tank, and the oxidation will be twice as large. After rotating around the roller (36) and (37), the yarn enters the third cell, etc., until it reaches the eighth cell, and when leaving each cell the wire rotates around the rollers (36). It should be noted, as shown in Figure 2, within the third and fourth vat there are three rollers (36), between the fourth and fifth vat there are four rollers (36), etc., until the exit of the eighth vat , where there are eight rollers (36). Therefore, the period of exposure to air increases progressively with the passage from the first cell to the octave, so that if a value of x is given to the oxidation process between the first cell and the second cell, the result will be successively: oxidation between 1st and 2nd tanks = x Oxidation value between 2nd and 3rd tanks = 2x Oxidation value between 3rd and 4th tanks = 3x Oxidation value between 4th and 5th tanks = 4x Oxidation value between 5th and 6th vats = 5x Oxidation value between 6th and 7th vats = 6x Oxidation value between 7th and 8th vats = 7x Oxidation value after 8th vault = 8x Dyebaths contain an aqueous solution of indoxyl containing from 6 to 8% by weight of pure indoxil. The wires pass through the baths at a speed of 20 to 60 m / min. according to the type and quality of the yarn.

Since the indoxyl reacts easily with oxygen in the air, the stability of the indoxyl baths in the vats (35) must be fixed before the solution is applied to the wire. This is done by adding to the bath a reducing mixture of sodium hydrosulfite (Na2S204) and sodium hydroxide (NaOH). At the interface between the bath and atmospheric air, the reducing bath reacts with oxygen according to the equation Na2S204 + 2NaOH + 1/202? H20 + 2 Na2S03 If necessary, if the oxidation period in the open air is too long, a forced air circulation can be applied by means of ventilation systems. The example shown in Figures 2 comprises 8 vats, but the operation can obviously be repeated two, three or more times using two, three or more sets of eight vats, thus achieving greater penetration of the indoxilo within the yarn. By means of this dyeing process, an abundant strong indigo coloring of the yarn is obtained. Once the yarn has been dyed, it is washed and pre-dried by means of a system (40) shown in Figure 3. The yarn is successively passed through the vats (41 to (45), guided by the rollers ( 46), (47) and (48) The tank (41) contains water and 50% acetic acid (CH3-COOH) is introduced into the tanks (42), (43) and (44), so that the Cuba (42) contains a proportion of 20 cm3 / l, Cuba (43) contains 10 cm3 / l and Cuba (44) contains 5 cm3 / L. Cuba (45) again contains water with the final pH being between 6 and 7, preferably 6.7.With leaving the tub (45), the yarn is prewired by rotating around the rollers (50) as can be seen in figure 3. After washing and pre-drying the yarn, it is prepared with the indigo dye to increase the firmness to washing and dyeing of the fabric to be subsequently prepared, by passing the yarn through the sizing system (60), shown in Figure 4. The yarn passes through the tub (62). ) what it contains a mixture of resins (63) and is guided through the tub by the guide rollers (64) and the squeezing rollers (61). The composition of the resin mixture is as follows: 10 to 50 g / l of quaternary salts of polyalkylamine. From 10 to 50 g / l of fluorocarbon resin. From 10 to 200 g / l of acrylic resin. From 1 to 20 g / l of autocatalyzed polysiloxane. From 10 to 200 g / l of polyurethane resin. During this sizing operation, a transparent film is formed on the yarn fibers which fix the indigo on the yarn, thus increasing the firmness to washing. After this sizing step, the yarn is dried by means of a system (70) shown in Figure 5, by passing the yarns around the rollers (71). This drying is carried out at a temperature between 150 and 180 ° C. Subsequently, the warp yarn is wound around the roller (72). The process according to the invention can be exploited using various types of yarn, for example, cotton, cotton and nylon, cotton and polyester, etc. The procedure and the system for exploiting the procedure are the preferred modalities. It should be noted that modifications can be made, it being understood that these modifications are also within the scope of the following claims.

Claims (17)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for dyeing an indigo textile material, characterized in that it comprises the following steps: a) prewash the yarn F by passing through a prewash system (1) composed of two or more tanks (2) containing a solution of prewash (10,15); b) subsequently dyeing the yarn by passing through a dyeing system (30) composed of a series of eight vats (35), each containing an indoxyl solution and during passage from one vat (35) to another, the yarn undergoes oxidation by exposure to air converting indoxyl to indigo, which then dyes the yarn by impregnation, oxidation being carried out by exposure to air in such a way that, during the passage from the first cell (35) to the eighth cell in succession, if a value x is given to the oxidation between the first cell (35) and the second cell, the following values will be successively obtained, the oxidation value between the 1a. and the 2nd. cubes = x, oxidation value between 2nd and 3rd tanks = 2x, oxidation value between 3rd. and the 4th tubs = 3x, oxidation value between the 4a. and the 5th. cubes = 4x, oxidation value between 5a. and the 6th. cubes = 5x, oxidation value between 6a. and the 7th. cubes = 6x, oxidation value between 7a. and the 8th. cubes = 7x, oxidation value after the eighth cell = 8x; c) washing and pre-drying the yarn by passing it through a washing and drying system (40) comprising a series of tanks (41, 42, 43, 44 and 45), the first tank (41) containing water, containing the tanks (42, 43, 44) acetic acid and the tank (45) containing water, so that the pH in the last tank is between 6 and 7 and, at the outlet of the tank (45), the yarn passing it between the rollers (50); d) priming the indigo dye on the yarn by passing it through a sizing system (60) comprising a tub (62) containing a mixture of resins in order to form a transparent film on the yarn fibers; e) drying the yarn by passing it through a drying system (60) composed of rollers (71); f) pick up the warp thread by winding it over the spool (72).

2. A process according to claim 1, further characterized in that during step a), a prewash solution containing a fatty alcohol phosphoric acid ester derivative, such as FINBIL AS, is employed.

3. A process according to claim 1, further characterized in that the dyeing solution in the tanks (35) is constituted by an aqueous solution of 6 to 8% by weight of pure indoxil.

4. A process according to claim 1, further characterized in that in step c), the solution of acetic acid in the tank (42) is obtained by adding 20 cm3 / l of 50% acetic acid to the tank (42). ), the acetic acid solution is obtained in the tank (43) adding 10 cm3 / l of 50% acetic acid to the tank (43) and a solution of acetic acid is obtained in the tank (44) adding 5 cm3 / 50% acetic acid to the tank (44).

5. - A method according to claim 1, further characterized in that the mixture of resins during step d), comprises a mixture of 10 to 50 g / l of polyalkylamine quaternary salts, from 10 to 50 g / l of fluorocarbon resin; from 10 to 200 g / l of acrylic resin, from 1 to 20 g / l of autocatalyzed polysiloxane, from 10 to 200 g / l of polyurethane resins.

6. A method according to claim 1, further characterized in that step d) can be repeated several times, using 16, 24 dyeing tanks (35) instead of eight.

7. A method according to claim 1, further characterized in that the yarns pass through the dyeing solutions at a speed of 20 to 60 m / min.

8. A system for exploiting the staining process according to claims 1 to 5, further characterized in that it comprises: a) a prewash system (1); b) a staining system (30); c) a washing and pre-drying system (40); d) a sizing system (60); e) a drying system (70).

9. A system according to claim 8, further characterized in that the prewash system comprises: two or several tanks (2) containing a prewash solution (10, 15), a guide roller (3) to guide the yarn to the prewash solution (10), a guide roller (4) to guide the yarn between two squeezing rollers (5) that guide the yarn to the guide roller (6), two squeezing rollers (7) to extract the excess liquid, a guide roller (8) that guides the wire to the washing liquid (15) in the second tub (2), a guide roller (9) that guides the wire to two squeezing rollers (12) , a guide roller (11) that leads the yarn back to the prewash solution (15) and two squeeze rollers (13) that dry the yarn at its outlet from the second tub (2).

10. A system according to claim 8, further characterized in that the staining system (30) comprises a series of 8 tanks (35) containing an indoxil bath, a series of rollers (31, 32, 33, 34). , 36 and 37) associated with each tub, the rollers (36) being arranged between each tub such that there is a roller (36) between the first and second tubs (35), two rollers (36) between the second and third tubs (35). tanks, three rollers (36) between the third and fourth tanks (35), etc., up to the eighth tank (35) and after this tank there are also eight rollers (36), making this roller arrangement (36) possible; The period of exposure of the yarn in the open air is progressively increased, so that this yarn is oxidized in such a way that if a value xa is given to the oxidation between the first cell (35) and the second cell, the following values are successively obtained: oxidation value between 1a. and the 2nd. cubes = x, oxidation value between 2nd and 3rd tanks = 2x, oxidation value between 3rd. and the 4th tubs = 3x, oxidation value between the 4a. and the 5th. cubes = 4x, oxidation value between 5a. and the 6th. cubes = 5x, oxidation value between 6a. and the 7th. cubes = 6x, oxidation value between 7a. and the 8th. cubes = 7x, oxidation value after the eighth cell = 8x.

11. - A system according to claim 8, further characterized in that the washing and pre-drying system (40) comprises a series of vats (41, 42, 43, 44 and 45) and rollers (46, 47 and 48) associated with each Cuba, containing the first tank (41) water, containing the tanks (42, 43 and 44) acetic acid and containing the tank (45) water, so that the pH in the last tank is between 6 and 7 and at the exit from the tub (45) there is a series of rollers (50) to dry the yarn.

12. A system according to claim 8, further characterized in that the sizing system (60) comprises a tank (62) containing a mixture of resins.

13. A system according to claim 8, further characterized in that during step a), a prewash solution containing a fatty alcohol phosphoric acid ester derivative, such as FINBIL AS, is employed.

14. A system according to claim 8, further characterized in that the dyeing solution in the tanks (35) is constituted by an aqueous solution of 6 to 8% by weight of pure indoxil.

15. A system according to claim 8, further characterized in that in step c), the solution of acetic acid in the tank (42) is obtained by adding 20 cm3 / l of 50% acetic acid to the tank (42), the acetic acid solution is obtained in the tank (43) by adding 10 cm3 / l of 50% acetic acid to the tank (43) and a solution of acetic acid is obtained in the tank (44) by adding 5% acetic acid to the tank (43). cm3 / l of 50% acetic acid to the cell (44).

16. A system according to claim 8, further characterized in that the mixture of resins during stage d), comprises a mixture of 10 to 50 g / l of quaternary salts of polyalkylamine, 10 to 50 g / l of resin of fluorocarbon; from 10 to 200 g / l of acrylic resin, from 1 to 20 g / l of autocatalyzed polysiloxane, from 10 to 200 g / l of polyurethane resins.

17. A system according to claim 8, further characterized by repeating step d) several times, using 16, 24 dyeing tanks (35) instead of eight.