WO2019142224A1

WO2019142224A1 - Method and installation for the continuous dyeing of yarns or fabric webs

Info

Publication number: WO2019142224A1
Application number: PCT/IT2019/050011
Authority: WO
Inventors: Attilio FRESCURA
Original assignee: Frescura Attilio
Priority date: 2018-01-19
Filing date: 2019-01-18
Publication date: 2019-07-25
Also published as: IT201800001329A1

Abstract

A method for the continuous dyeing of yarns or fabric webs comprises the following phases: a. bringing the dye to the surface of the fiber by means of a series of impregnations of new dyeing baths; b. supporting the diffusion and the fixation of the dye by means of an adequate time of exposure in an inert atmosphere ensuring ring dyeing by means of the white fiber core and enhancing the adsorption partially; and c. alternating with pressing processes in order to have the baths in conditions of releasing color several times. The method is performed by an installation for the continuous dyeing of yarns or fabric webs.

Description

METHOD AND INSTALLATION FOR THE CONTINUOUS DYEING OF YARNS OR FABRIC WEBS

The present invention relates to a method and an installation for the continuous dyeing of yarns or fabric webs.

In general, the present invention relates to fixing of chemical products, for example, dyes, on textile materials, subsequent treatments of textile materials by means of liquids, gases or vapors, preservation of textile materials in association with the treatment of materials with liquids, gases or vapors, the textile materials passing through a chamber, containers with means for introducing or removing textile materials without changing the pressure of the container.

In particular, the present invention refers to the passage of textile materials through liquids, gases or vapors for carrying out the treatment, for example, washing, dyeing, bleaching, sizing, impregnation of fabrics combined with squeezing.

The lack of affinity of a dye such as indigo and the request for a superficial dye to guarantee the white core of the yarn involves the use of a technology based on a dyeing cycle repeated several times with different tanks until the required shade is obtained . The dyeing cycle comprises a first step in which the yarn is impregnated with the dyeing bath, followed by a second squeezing step to eliminate the excess of bath and a third step to oxidize the dye on the fiber.

The technology used for over a century to dye continuously with indigo consists of repeating the sequence several times: impregnation in a color bath; squeezing; and oxidation until the desired shade is obtained. This technology involves a series of problems: numerous dyeing tanks with large bath volumes, high consumption of products especially hydrosulphite, with a consequent increase in the pollutant load.

In recent years, a new technology has developed that involves exposure in an inert environment, after the impregnation in the color bath, to improve the spread and fixation of the indigo.

The state of the art is represented by the patent application DE 4 342 313 A1 regarding an assembly to apply an indigo dyestuff to textile warps with a wet dwelling stretch protected from air entry by inlet and outlet locks.

The state of the art is also represented by the patent EP 0 799 924 B1 regarding a method for continuous dyeing of warp chains by means of a plant comprising a dyeing reactor inside which the time of residence of the warp chains can be set without changing the volume of the bathroom. After the initial impregnation in the dyeing bath, the warp is squeezed into an intermediate squeezer located in the reactor. Intermediate fixing takes place on the guide cylinders, without oxygen. The time of residence of the warp in the reactor can be adjusted according to the desired shade and according to the technological conditions corresponding to the dye employed. An intermediate squeezer is installed inside the reactor, the pressure of which can be set as required until the pressure is completely absent. Thanks to the guide cylinders which can be moved vertically inside the reactor, the residence time of the warp can be extended or reduced depending on the technological needs. After the initial immersion in the new bath, the warp is squeezed into the intermediate squeezer located in the reactor. Then the fixing process takes place on the guide / immersion cylinders without oxygen and without another immersion in the fresh bath. The warp after its insertion in the reactor is immersed in an indigo bath with a volume of less than 300 liters and a concentration of 3 g / l. Thereafter, the warp is squeezed in intermediate squeezer thus reducing the warp concentration to almost half. The method is distinguished by the fact that in order to avoid oxidation of the dye inside the hermetically sealed reactor an inert gas is fed, for example nitrogen. In order to avoid oxidation of the dye inside the hermetically sealed reactor, the air on the incoming warp is eliminated by squeezing under bath on the squeezer installed at the reactor inlet. In order to obtain different shades and resistance to washing, the squeezing of the warp in the intermediate squeezer can be set with different values or excluded. The motorized cylinders and the guide cylinders in order to lengthen or shorten the warp are adjustable for vertical movement.

The invention of the patent EP 0 799 924 B1 is based on a different concentration of dye in the dyeing tanks, so that the concentration of the bath in the outlet tank can be reduced to the minimum necessary for the purpose of economy of the dye, so that after squeezing the warp, only a small part of the unfixed dye remains to be removed in the rinse tank.

The state of the art is also represented by the patent EP 1 971 713 B1 concerning a device and a continuous dyeing process with indigo for the warp yarn and / or fabric chains equipped with a first hermetically sealed dyeing compartment suitable to contain the dyeing bath, and a fixation / dehydration compartment of the hermetically sealed yarn. The two dyeing and fixation / dehydration compartments, in an inert environment and functionally and hermetically connected to each other, comprise means for introducing nitrogen and / or deoxygenated air into the same compartments. Inside the compartment there is at least one means for directly heating and / or dehydrating the yarn, and at least one squeezing element capable of exerting a strong pressure on the yarn chain. The means for injecting deoxygenated air and / or nitrogen inside the compartment comprise at least one inlet nozzle connected to a source of deoxygenated air and nitrogen under pressure. The dyeing compartment comprises at least one intermediate squeezing group suitable for exerting a squeezing on the yarn.

The invention of patent EP 1 971 713 B1 allows to reduce the consumption of hydrosulphite and soda and consequently allows to reduce the salinity of the dyeing bath. Also reduces considerably: the number of dyeing tanks and, consequently, the size and cost of the machine; the length of the yarn in the air paths for the oxidation and consequently the waste at each change of the match. From the point of view of the quality of the product it is obtained: increasing of the diffusion and fixation of the dye in the fiber, greater capacity of absorption of the dye, pick up, color yields and strength much higher than those obtainable with the known technique, with consequent saving of dye and less pollution of the washing waters. Moreover, the invention of the patent EP 1 971 713 B1 has the limit of dyeing with full penetration of indigo without leaving white core into the fiber.

The above described state of the art presents various solutions with advantages and disadvantages.

For this, there is a need to incorporate the advantages emerged from the analysis of the state of the art and at the same time solve the problems by resorting to a universal solution.

Object of the present invention is solving the above prior art problems by providing a method and an installation for the continuous dyeing of yarns or fabric webs capable of exploiting the dyeing technology in an inert environment to achieve the maximum possible dyeing performance for units in the application in continuous of indigo.

A further object is to allow the number of dives to be varied according to the dyeing required ensuring with an excellent color fixation ring the peculiarity of the dyeing.

A further object is to provide a method and an installation for the continuous dyeing of yarns or fabric webs which allows to re-impregnate the plurality of yarns or fabric webs after one or more immersions without necessarily oxidizing the dye, thus making it possible to reduce considerably the dyeing units.

The above and other objects and advantages of the invention, as will become clear from the following description, are achieved with a method and an installation for the continuous dyeing of yarns or fabric webs as described in the claims. Preferred embodiments and non-trivial variants of the present invention form the object of the dependent claims.

It is to be understood that all the claims form an integral part of the present description.

It will be immediately obvious to the skilled people in the art that could be performed to what has been described numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) without departing from the scope of protection of the invention as appears from the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, given as a non-limiting example, with reference to the enclosed drawings, in which:

Fig. 1 shows an axonometric view of an embodiment of the installation for the continuous dyeing of yarns or fabric webs according to the present invention;

Fig. 2 shows a front view of the previous figure; and

Fig. 3 shows an auxiliary service system connected to the installation of the previous figure.

A method for the continuous dyeing of yarns or fabric webs is performed by means of: impregnation of the yarns or fabric webs in a dyeing bath; permanency of said yarns or fabric webs in an inert atmosphere for retaining the dyeing bath substance and allowing penetration / diffusion of the dyeing bath substance in the yarns or fabric webs; squeezing of the yarns or fabric webs; and fixing the dyeing bath to the yarns or fabric webs.

This method comprises the following phases:

a) bringing the dye to the surface of the fiber by means of a series of impregnations of new dyeing baths;

b) supporting the diffusion and the fixation of the dye by means of an adequate time of exposure in an inert atmosphere ensuring ring dyeing by means of the white fiber core and enhancing the adsorption partially; and

c) alternating with pressing processes in order to have the baths in conditions of releasing color several times.

In particular, the series of impregnation of new dyeing baths is performed using the same dyeing bath.

With reference to Figs. 1, 3, it is possible to note that an installation for the continuous dyeing of yarns or fabric webs, comprises an apparatus for impregnation of the yarns or fabric webs in a dyeing bath 10, an apparatus for permanency of the yarns or fabric webs in an inert atmosphere for retaining the substance of the dyeing bath and allowing the penetration / diffusion of the substance of the dyeing bath in of the yarns or fabric webs 20, an apparatus for squeezing of yarns or fabric webs 30 and an apparatus for fixing the dyeing bath to the yarns or fabric webs 40.

Advantageously, means 100 are provided to vary the extent of the dyeing bath, means 201, 202, 203 to vary the extent of the apparatus in inert atmosphere and means 301, 302, so as to vary the number of passages through the apparatus of squeezing.

The means 100 to vary the extent of the dyeing bath comprise a hydraulic circuit 100in of introduction of the substance of the dyeing bath, to increase the extension of the dyeing bath by means of at least a controlled valve CB-1, CB-2, CB-3, and a hydraulic circuit 100out of emission of the substance of the dyeing bath, to reduce the extension of the dyeing bath by means of at least a controlled valve SC-1, TP-1, SC-2, TP-2, SC-3, TP-3, SC-4, TP-4.

The means 201, 202, 203, to vary the extent of the apparatus in inert atmosphere comprise a plurality of movable controlled return cylinders to vary the reciprocal distance by a respective fixed transmission cylinder 21, 22, 23.

The means 301, 302, to vary the number of passages through the squeezing apparatus comprise a plurality of mobile pressure cylinders controlled so as to vary the pressure exerted on a respective fixed pressure cylinder 31, 32.

With reference to Fig. 2, the apparatus for impregnation of the yarns or fabric webs in a dyeing bath 10 consists of a tank 5 formed by a plurality of compartments 51, 52, 53, 54, each compartment being filled with the substance of the dyeing bath depending on a certain tone of dyeing required.

The hydraulic circuit 100in of introduction of the substance of the dyeing bath and the hydraulic circuit 100out of emission of the substance of the dyeing bath concern both a substance of the single dyeing bath so as not to alter the concentration of the dyeing bath.

Each cylinder of moving pressure 301, 302, means to vary the number of passages through the pressing apparatus is activated in function of a certain tone of dyeing required.

In particular, the movable pressure cylinder 301 of the means to vary the number of passages through the apparatus of squeezing is activated as a function of the respective compartment 51 filled with the substance of the dyeing bath.

In the same way, the movable pressure cylinder 302 of the means so as to vary the number of passages through the apparatus of squeezing is activated as a function of the respective compartment 52 filled with the substance of the dyeing bath.

The dwelling apparatus 20 in an inert atmosphere and the squeezing apparatus 30 are both located inside a cover 6.

The cover 6 is removable in order to allow the maintenance of the installation.

Moreover, the cover 6 is connected to the tank 5 via watertight interface.

The fixation apparatus of the substance of the dyeing bath 40 is located externally to the cover 6 and downstream with respect to the apparatus of impregnation in a dyeing bath 10, to the apparatus of permanence in inert atmosphere 20, and to the apparatus of squeezing 30.

Examples

The method for the continuous dyeing of yarns or fabric webs allows to achieve the intended aim and objects.

The main purpose is that of the processing of a plurality of yarns or fabric webs in a dyeing process, in particular with indigo dyes or reduction mainly in an inert environment.

At each immersion there is an increase of ascent of dye on the fiber, in such a way as to be able to vary the number of dives before the oxidation step.

The dyeing is a succession of processes represented by the following equilibria: dye in the dyeing bath in equilibrium; dye adsorbed by the fiber; and dye diffusion.

It is possible to distinguish the following steps: transport of the dye from the bath to the surface of the fiber; adsorption of the dye on the surface of the fiber; diffusion of the dye from the surface to the interior of the fiber.

The Installation for the continuous dyeing of yarns or fabric webs according to the present invention utilizes a multi-immersion process in an inert atmosphere for:

a) bringing the dye to the surface of the fiber by means of a series of impregnations of new bath which alternate with pressing in order to have the bath several times in conditions of yielding color;

b) supporting the diffusion and the fixation of the dye with an adequate time of exposure in an inert atmosphere, ensuring the dyeing white ring of the fiber core;

c) encouraging the adsorption in a partial manner, using more dives to facilitate the distribution of crystalline dye molecules in the area of the fiber. This is necessary to distribute the dye molecules in an orderly manner and to avoid a chaotic slope which makes the dye less bright and less solid;

d) using the same dyeing bath to obtain more or less dark shades by changing only the number of dives in each module.

The system includes: a plurality of compartments provided with overflow bath circulation and discharges; a plurality of pairs of pressure cylinders; a plurality of guide deviation cylinders; and a removable cover.

Hydraulic seals at the inlet and at the outlet of the installation allow the passage of the beam of yarns or fabric webs and isolate the inside of the cover to maintain the condition of inert atmosphere.

The tank in the compartment at the inlet and at the outlet houses the walls which descend beyond level of the bath to create the hydraulic seals.

The path of the beam of yarns or fabric webs is designed so as to be able as compact as possible and to be used also by excluding the pairs of pressure cylinders.

In this way, the total volume of the dyeing bath is reduced to less than 800 liters and the oxidation steps are reduced of number to ensure a saving of products, a less waste of yarn and an easier management of the concentration of the baths and of their temperature.

In the tank of the dyeing bath, the compartment at the inlet contains a series of guide cylinders to allow the passage of the beam of yarns or fabric webs. In the lower part, on the whole height is inserted the distribution of the delivery of the circulation bath, in the upper part and on the opposite side to the inlet in the whole height, there is the hopper with the function of recovering the bath. By means of the pneumatic valve, the bath is returned into circulation avoiding to feed the next tank.

Referring to Fig. 3, the fixing apparatus of the dyeing bath substance comprises a foulard unit 401 which works in the atmosphere, always with the maximum squeezing force to eliminate as much bath as possible. The foulard 401 constitutes the main element of driving the yarns or fabric webs and remains always active. The squeezing unit 30 is located in an inert environment and the foulard unit 301 and 302 can vary the squeezing force or be deactivated according to the shade or process. The number of compartments and the number of foulards of squeezing unit may vary.

Constructively the foulards are identical, but the one in the external environment operates differently having to always squeeze with maximum force to eliminate as much bath as possible and to do towing without ever being deactivated.

The dyeing bath in the inlet compartment 51 can be used with two different levels:

level H, top, with the pneumatic valve TP-1 closed to allow the substance of the dyeing bath to overflow the next compartment 52;

Level L, low, with the pneumatic valve TP-1 open, to allow the substance of the dyeing bath to return to the dyeing bath circulation of the aspiration circuit 100out, the compartments of the tank 52, 53, 54 remaining empty. This condition allows dyed with a volume of bath reduced of the sulfur dyes which do not need of a large number of impregnation or inert atmosphere.

It is also possible to dye the indigo with the compartment 51 of the tank at level L, low, but it is necessary to fill the compartment 54 through a second circulation of the substance of the dyeing bath via the pneumatic valve CB-3 to ensure the hydraulic seal both at the inlet and the outlet and allow to operate in inert atmosphere. In this case the pneumatic overflow valve TP-3 is activated.

The supply of the compartment 54 of the tank 5 can be independent using the delivery of the circulation by opening the valve CB-3.

Alternatively, in the case of the use of the compartment 53 of the dyeing tank 5, the compartment 54 is fed by overflow of the compartment 53 which can in turn be supplied by overflow of the compartment 52, or by the introduction of the substance of the dyeing bath through the pneumatic valve CB-2. In this case the pneumatic valve TP-3 of overflow is closed and the level is given by the pneumatic valve TP-4 of overflow, to the outlet of the compartment 54, the substance of the dyeing bath being returned to circulation on the inlet circuit 100out.

The dyeing bath in the compartment 52 of the dyeing tank 5 is fed by overflow upstream of the compartment 51, when the pneumatic valve of the overflow TP-1 is closed, the outlet compartment 52 having the hopper which collects the substance of the bath of dyeing and through the pneumatic valve of the overflow TP-2 puts it back into the circulation in the inlet circuit 100out.

The bath of the compartment 53 of the dyeing tank 5 is fed by overflow of the compartment 52 of the dyeing tank, with the pneumatic valve TP-2 closed.

The bath of the compartment 54 of the dyeing tank 5 can be supplied by the overflow of the compartment upstream 53, or by the flow of the bath circulation through the opening of the pneumatic valve CB-2.

The level with all the compartments of the dyeing tank working and with the active circulation is given from the hopper overflow of the compartment 54 in output from the installation, recycling the circulation of the dyeing bath substance by means of the pneumatic valve TP-4.

According to a preferred configuration, the Installation according to the present invention allows the dyeing of the beam of yarns or fabric webs with one, two, three or four dives.

Moreover, the Installation allows to squeeze after each immersion in the bath with the pairs of pressure cylinders of the squeezing apparatus 30 and, possibly, also with the pair of cylinders of pressure upstream of the fixing apparatus of substance of the dyeing bath 40. All the compartments of the dyeing tank 5 are provided with a bath drain recovered in a single tank.

The Installation allows to achieve the maximum dyeing yield of the indigo per unit before the oxidation step.

The Installation has a significantly low bath volume in relation to the number of dives.

The drawing-in can be changed according to the required diffusion time.

Claims

Method for the continuous dyeing of yarns or fabric webs, by means of: impregnation of the yarns or fabric webs in a dyeing bath; permanency of said yarns or fabric webs in an inert atmosphere for retaining the dyeing bath substance and allowing penetration / diffusion of the dyeing bath substance in the yarns or fabric webs; squeezing of the yarns or fabric webs; and fixing the dyeing bath to the yarns or fabric webs; characterized in that said method comprises the following phases: a) bringing the dye to the surface of the fiber by means of a series of impregnations of new dyeing baths; b) supporting the diffusion and the fixation of the dye by means of an adequate time of exposure in an inert atmosphere ensuring ring dyeing by means of the white fiber core and enhancing the adsorption partially; and c) alternating with pressing processes in order to have the baths in conditions of releasing color several times.
Method according to the previous claim, characterized in that said series of impregnation of new dyeing baths is performed using the same dyeing bath.
Installation for the continuous dyeing of yarns or fabric webs, comprising an apparatus for impregnation of the yarns or fabric webs in a dyeing bath (10), an apparatus for permanency of said yarns or fabric webs in an inert atmosphere for retaining the dyeing bath substance and allowing penetration / diffusion of the dyeing bath substance in the yarns or fabric webs (20), an apparatus for squeezing the yarns or fabric webs (30) and an apparatus for fixing the dyeing bath to the yarns or fabric webs (40), characterized in that the installation comprises means for varying the dyeing bath extension, (100), means to vary the extent of the apparatus in an inert atmosphere, (201), (202), (203), and means for varying the number of passes through the squeezing apparatus, (301), (302).
Installation for the continuous dyeing of yarns or fabric webs according to the previous claim, characterized in that the means for varying the extension of the dyeing bath, (100), comprise a hydraulic circuit for introducing the substance of the dyeing bath, (100in), to increase the extension of the dyeing bath by at least one controlled valve (CB-1), (CB-2), (CB-3), and a hydraulic circuit for the emission of the substance of the dyeing bath, (100out), to decrease the extension of the dyeing bath by at least one controlled valve (SC-1), (TP-1), (SC-2), (TP-2), (SC-3), (TP-3 ) (SC-4), (TP-4).
Installation for the continuous dyeing of yarns or fabric webs according to one of the preceding claims, characterized in that the apparatus for impregnation of the yarns or fabric webs in a dyeing bath (10) consists of a tank (5) formed by a plurality of compartments (51), (52), (53), (54), each of said compartments (51), (52), (53), (54) filled with the substance of the dyeing bath according to a certain required dyeing tone.
Installation for the continuous dyeing of yarns or fabric webs according to the previous claim, characterized in that both the hydraulic circuit for injecting the substance of the dyeing bath (100in), and the hydraulic circuit for the emission of the substance of the dyeing bath, (100out), concern a substance of the single dyeing bath in order not to alter the concentration of the dyeing bath.
Installation for the continuous dyeing of yarns or fabric webs according to one of the preceding claims, characterized in that both the in-inert- atmosphere permanency apparatus (20) and the squeezing apparatus (30) are located inside a cover (6), said cover (6) being removable to allow maintenance of the system and connected to said tank (5) through a watertight interface.
Installation for the continuous dyeing of yarns or fabric webs according to one of the preceding claims, characterized in that the substance of the dyeing bath fixation apparatus (40) is located outside the container (6) and downstream from an apparatus for impregnation of the yarns or fabric webs in a dyeing bath (10), from an apparatus (20) and from a squeezing apparatus (30).