Abstract:
A of continuous treatment of a textile product web with steam is performed by applying a reactive dye on moist product web of natural fibers; bringing the moist product web with the reactive dye in contact with steam; using the steam in form of hot steam which is overheated water steam, with a temperature of 130-230° C.; transporting the product web during a steam treatment at least partially horizontally through at least one treatment chamber; and blowing the hot steam into the at least one treatment chamber onto the product web by nozzle boxes arranged above and below of the product web. The device is also provided for performing the method.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a method for continuous treatment of a textile product web with steam for fixing a reactive dye on natural fibers.  
           [0002]    It also relates to a device for continuous treatment of textile product web of this type.  
           [0003]    For fixing of reactive dyes on natural fibers, such as cotton or cellulose it is known first to dry the moist product web on which the reactive dye is applied, and subsequently to leave the dye for reaction with the fibers of the product web. For this purpose aide, such as for example urea is needed and admixed to the reactive. dye. The aide holds the reactive dye during dying in solution and evaporates during fixing. This is true both for application of reactive dye on the product web by coloring and also by pressing.  
           [0004]    For fixing of the reactive dye applied by pressing, it is known to treat the dried product web with saturated steam. A corresponding device with a steam chamber is disclosed in the patent document EP 0607 762B. For reduction of the urea consumption, this device is provided with a pre-moisturizing chamber.  
           [0005]    A reduction of the urea quantity is possible, as described in the German patent document DE 43 03 129 C2, in that the printed and dried product is sprayed with water immediately before its entry in the rapid festoon ager. This fixing process in the rapid festoon ager requires an average steam time of 10-15 minutes. The product extends amounts in general to 80-490 m, whereby a product speed is from 5 to 50 m/min. In the rapid festoon ager the fixing of the reactive dye is performed conventionally with saturated steam at substantially atmospheric pressure, or in otherwords in saturated steam atmosphere. Rapid festoon ager with a product extent of at least 80 meter is not efficient usable for smaller quantities to be covered (smaller meter lengths).  
           [0006]    A further appropriate steamer is disclosed in the German patent document DE 23 10 195 C2. This steamer has a treatment chamber and a transporting device with at least partially horizontal product guidance by means of a conveyor. The treatment chamber is formed as a downwardly open hood. Thereby the entrained air can fall from the downwardly open steam space, so that always a pure steam atmosphere is available. A fixing of a drying product web in this steam atmosphere, in which also a purely saturated steam atmosphere is provided, is not possible without urea. The advantage of this steamer is that, due to the above mentioned steam type with saturated steam atmosphere of 10-15 mm in a continuous operation, only small product speeds can be reached. Higher product speeds are possible only with greater structural length of the steamer with correspondingly higher investments and operation costs. The steam also is not efficiently usable for smaller quantities to be colored.  
           [0007]    A further disadvantage of the above mentioned method is that the product web after application of reactive dye soluble in water is first dried and subsequently the reactive dye is fixed on the fibers. The both treatment stages of drying and fixing require two treatment devices. During pressing, conventionally for drying a pressing chamber and for fixing the above mentioned steam device are utilized.  
           [0008]    In a special pressing method which is disclosed in the German patent document DE 196 33 101 the product web is moisturized, wet pressed and in wet condition evaporated without intermediate drying. The steaming is performed in a saturated steam atmosphere during 1.0-20 min at 96-105° C. Also, in this method during use of a reactive dye for printing of cotton, urea in conventional quantity is utilized.  
           [0009]    A further special pressing method in which the product web is first moisturized, the wet product web is printed and subsequently an evaporation-thermosol fixation process is performed, it is disclosed in the patent document W096/28604. The evaporation-thermosol fixation process takes place with saturated steam at temperatures of 90, 150 and 170° C. It requires a pressure-tight fixing device which conventionally is suitable only for a discontinuous operation.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, it is an object of present invention to provide a method of continuous treatment of a textile product web with steam for fixing of reactor dye on natural fibers which avoids the disadvantages of the prior art and which is suitable for smaller meter lengths efficiently.  
           [0011]    In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated in a method of treatment of a textile product web with steam for fixing of reactive dye on natural fibers, which includes the steps of applying a reactive dye on moist product web of natural fibers; bringing the moist product web with the reactive dye in contact with steam; using the steam in form of hot steam which is overheated water steam, with a temperature of 130-230° C.; transporting the product web during a steam treatment at least partially horizontally through at least one treatment chamber; and blowing the hot steam into the at least one treatment chamber onto the product web by nozzle boxes arranged above and below of the product web.  
           [0012]    It is also an object of present invention to provide a device for continuous treatment of a textile product web with steam for fixing of reactive dye on natural fibers in which the inventive method can be realized.  
           [0013]    In keeping with these objects another feature of present invention resides, briefly stated at least one treatment chamber, a transporting device having a horizontal conveyor guided through the at least one treatment chamber, a steam-tight housing which surrounds the at least one treatment chamber, the at least one treatment chamber being provided with at least one circulating device with at least one circulating fan and also with nozzle boxes arranged above and below the product web, the conveyor being formed as a sieve band.  
           [0014]    When the method is performed and the device is designed in accordance with the present invention, the steam treatment can be performed effectively and thereby fast. Also, for fixing printed product webs are suitable.  
           [0015]    In a method for continuous treatment of a textile product web with steam in which a moist product web of natural fibers with an applied reactive dye is brought in contact with steam, is subjected also to steam treatment, fixing treatment or dye fixing, with the steam, in accordance with the present invention in form of hot steam, or in other words overheated water steam at substantially atmospheric pressure. The hot steam is composed at least of 80 vol. %, preferably 95-100 vol. % (pure hot steam), of water steam. The hot steam has a temperature of 130-230° C. in particular of 160-230° C. In addition to the high product web temperature which with pure hot steam amounts to 100° C., the additional temperature difference between the hot steam and the product web of 30° , in particular 60° up to 130° C. makes possible an acceleration of the reaction of the reactive dye with the natural fibers. This leads, when compared with a fixing treatment in saturated atmosphere to reduced heating and fixing time, and correspondently reduced retention time in a steamed treatment device and allows therefore devices which can be used efficiently for shorter meter length.  
           [0016]    It is important for the inventive method that with the use of hot steam, the moist product web is dried during the steam treatment. It has been shown that a drying of the product during the fixing treatment leads to an acceleration reaction of the reactive dye with the natural fibers. This results in a further reduction of the fixing time.  
           [0017]    In the event treatment method for many reactive dyes it is also possible to get rid of the use of urea. This is true for dyes of textile product webs in which the product webs colored with reactive dyes have a moisture of for example 40-80%. This is true also for the printing of textile product webs, in which the product webs printed with reactive dye have a moisture of for example 10-40%.  
           [0018]    In a surprising manner this treatment methods with hot steam and with an enhanced drying leads to a good fixing results, namely to a high color yield and a good coloring quality which corresponds to the result of the prior art.  
           [0019]    In accordance with the present invention the product web during the steam treatment is transported at least partially horizontal through at least one treatment chamber. The horizontal product web guidance makes possible a fine transportation of the moist product web with the reactive dye applied on it. In contrast to this, in a roller conveyor steamer or in a rapid festoon ager due to the vertical product web guidance there is a danger of dye running. The use of a horizontal product web guidance, which with saturation steam atmosphere with the product extent requires a great structural volumes, is usable in connection with the efficient steam treatment with heat steam also for smaller meter length.  
           [0020]    In accordance with the present invention, the hot steam in the treatment chambers is blown onto the product web by nozzle box arranged above and below the product path. Preferably, the hot steam is guided in circulating process. In contrast to the adjusting saturated steam atmosphere disclosed in the German patent document DE 23 10 195 C2 without significant flow speed, the product web is blasted with hot steam. The blasting makes possible a higher exchange rate of the treatment steam on the outer surface of the product web and thereby a stronger energy supply per time than in a stationary steam atmosphere. By the blasting, the steam treatment is further efficient and the usability of the inventive method for small meter length is improved.  
           [0021]    The utilization of hot steam when compared with saturated steam, during the blasting through a circulating system has the advantage of a lower danger of condensation in the circulating system. With the use of the inventive method for printing of textile product webs, the moisture of the printed product web before the steam treatment is adjusted to 10-40%, in particular 15-25% and the product web is dried during the steam treatment to the residual moisture of 1-10% in particular 3-7%. In surprising manner, it has been determined that with the inventive method for a printed product web, optimal fixing results can be obtained with a residual moisture of the product web smaller than the equilibrium moisture. The equilibrium moisture amounts under normal conditions to substantially 10% moisture to the weight of the product web for cellulose and substantially 8% moisture for cotton. A regulation of the residual moisture of the product web in the treatment chambers is not necessary.  
           [0022]    The retention type of the product web in the treatment chamber can be 35-60 seconds, preferably 10-20 seconds. This time is sufficient for drying and for complete fixing of good dye yield. It makes possible to provide a device with small structural dimensions.  
           [0023]    By the transportation of the product web by means of a sieve band, on the one hand a transportation of the product web through the treatment chamber can be performed without contact with the printed surfaces, and on the other hand a steam supply from above and from below on the product web is possible.  
           [0024]    An arrangement for continuous treatment is also provided in accordance with the present invention. Since it has a steam-tight housing which surrounds all treatment chambers, the use of heat steam is possible. By means of the circulating devices with at least one circulating fan and nozzle boxes arranged above and below the product web, the steam treatment with hot steam is effective also with the fine, horizontal product web guidance.  
           [0025]    The arrangement in accordance with the present invention is especially suitable for fixing of small meter lengths.  
           [0026]    The transportation of the product web by a conveyor formed as a sieve band makes possible, with a contact-free transportation of the printed circuit of the product web, a steam supplied from above and below onto the product web. The device is therefore especially suitable for dye fixing of the printed product webs.  
           [0027]    A great opening degree of the sieve band makes possible a great contact surface of the product web for hot steam. This leads to a high exchange rate and thereby to an efficient steam treatment. The deviating rollers for the conveyor formed as the sieve band arranged above the steam-tight housing simplified the construction of the arrangement. However, slots must be provided for entry and exit of the conveyor.  
           [0028]    A return guidance of the conveyor under the housing requires  32  only an inlet slot and an outlet slot for the conveyor and makes possible an arrangement of a tensioning system and a drive for the conveyor outside of the steam-tight housing. This simplifies the construction of the arrangement. A guiding band can extend at an acute angle to a vertical through the inlet lock. It can be formed by the conveyor itself or a further band. It allows deviations of the product web by an angle of greater than 90°. Thereby the danger of negatively affecting the printing image by excessive deviations of the product web, such as in the case of a deviation around 90°, is reduced. The acute angle amounts to approximately 30-60°.  
           [0029]    A supply band which extends in the vicinity of the conveyor running through the treatment chambers simplifies the supply of the starting portion of a new product web to the conveyor.  
           [0030]    A supply band which extends through the inlet lock is especially suitable for devices with a conveyor running back through the treatment chamber.  
           [0031]    In accordance with a further feature of present invention, locks are arranged before and after the housing. The locks extend from the bottom to over the transporting plane of the product web and are subdivided into a lower, downwardly open prechamber and a main chamber arranged over it. Suction passages or suction boxes can be connected with the prechamber. When compared with the known inlet and outlet slots with the suction boxes disclosed in the German patent document DE-A 195 46 344, due to the separate locks with the prechamber and aspiration device, the penetration of air and thereby condensation of steam to water is reliably prevented. A lock which is known from the German patent document DE 198 58 339, in which before the inlet slot of the housing steam is blown onto the product web, is less suitable for fixing of dye because of the danger of dye running.  
           [0032]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]    [0033]FIG. 1 is a view showing a device for printing a textile product web with an inventive arrangement for dye fixing in accordance with a first embodiment of the present invention;  
         [0034]    [0034]FIG. 2 is a view showing this arrangement with a schematic cross-section; and  
         [0035]    [0035]FIG. 3 shows an inventive arrangement for dye fixing in accordance with a second embodiment of the present invention also with a schematic cross-section.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0036]    A device for printing of a textile product web  1  of natural fibers, for example of cotton or cellulose, with reactive dye has units which are arranged one after the other in a transporting direction and include a product storage  2 , a supply device  3 , a printing device  40 , a device for dye fixing  6 , a further supply device  7 , and a further product storage  8 . In this example the front product storage  2  is formed as a winder, the front supply device  3  is formed as a boom, the rear supply device  7  is formed as a taking off table and rear product storage  8  is formed as a container. The printing device  40  is formed as a rotary printing press. Alternatively also another printing press can be used such as for example a flat bed printing machine or an ink-jet printing machine.  
         [0037]    The device  6  for dye fixing has an inlet lock  9 , a steam-tight heat insulating housing  1   0 , and an outlet lock  11 . The housing  10  includes one or several, preferably one to four, modular treatment chambers  12  arranged in a row. The interior of the housing  10  is subdivided by the treatment chambers  12  into one or several successive fields. The housing  1   0  is not subdivided and embraces all treatment chambers, in this example a treatment chamber  12 .  
         [0038]    A circulating device is provided in each treatment chamber  12 . It is a device for guiding hot steam in a circulation, known as a circulating process with at least one circulating fan  14 , at least one heating device which is not shown in the drawings and a nozzle box  15  with nozzle openings directed toward the product web  1 . The nozzle boxes  16  are arranged above and below the product web  1  and extend transversely over the product level  1 . In a treatment chamber  12 , one or several upper and lower nozzle boxes  15  can be arranged one after the other. In this example the treatment chamber  12  is provided with four nozzle boxes  15  arranged above and four nozzle boxes arranged below and with two circulating fans  14 . Each of the circulating fans  14  is associated with two upper and two lower nozzle boxes  15 . The upper and lower nozzle boxes  15  can be arranged so that they are offset opposite to or relative to one another. The nozzle openings of the nozzle boxes  15  are preferably formed as slots.  
         [0039]    The transporting device has a rotating conveyor which is formed as a sieve band  41 . It is guided by two upper deviating rollers  42 ,  43  with its upper run through the treatment chamber  12  and by two lower deviating rollers  44 ,  45  with its lower run through the treatment chamber  12  and underneath the housing  10 . The upper front deviating roller  42  is located completely in the inlet lock  9  and the upper rear deviating roller  43  is located completely in the outer lock  11 . Their arrangement is such that, the product web  1  is guided in the treatment chamber  12  flat and horizontal, or in other words in a horizontal transporting plane. One of the lower deviating rollers  44 ,  45  is connected with a not shown drive.  
         [0040]    The transporting device also has a not shown, conventional tensioning device, with which the sieve band  41  is tensioned, as well as not shown supporting devices in the treatment chamber  12 . The supporting devices can be formed by a longitudinal slide arranged at the sides on the nozzle boxes  15  or by supporting rollers arranged between the nozzle boxes  15 .  
         [0041]    The sieve band  41  has an open surface over at least 50% to maximum 90%. It is composed in this example of a metal link conveyor with an open surface over 80% and has on its sides chain links. Correspondingly, the deviating rollers  43 ,  44 ,  45  and  46  are provided on its sides with toothed gears. Alternatively, the sieve band  41  can be formed as perforated metal band or as a glass fabric band. The housing  10  has an inlet slot  27  in a front wall  26  and an outlet slot  29  in a rear wall  28 . The product web  1  can be introduced into the housing  10  and withdrawn from it through the inlet slot  27  and the outlet slot  29  correspondingly.  
         [0042]    The inlet lock  9  has a front plate  31  which extends parallel to the front wall  26  in the vicinity of a lower edge  30  to above the inlet slot  27 , a cover plate  32  and two not shown side plates. The plates  31 ,  32  of the inlet slot  9  are connected steam-tightly with one another and with the front wall  26 . The inlet lock  9  is extended by the intermediate plates  33 ,  34  which extend from the front plate  31  and from the front wall  26  into the interior of the inlet lock  9 . A gap  35  is maintained between them for the product web  1  and in some cases a conveyor, so that it is subdivided into an upper main chamber  36  and a lower pre-chamber  37 . The pre-chamber  37  is open downwardly. A suction device, in this case a suction passage  38  connected with a not shown fan, is connected to the pre-chamber  37 . In some cases, a as in the shown example, a suction box  39  is provided in the pre-chamber  37  to which the suction passage  38  is connected. The deviating roller  44  of the transporting device is located directly under the pre-chamber  37  and the deviating roller  42  is located before the inlet slot  27 .  
         [0043]    The outlet lock  11  is formed analogously as the inlet lock  9 . The deviating rollers  43 ,  45  are arranged analogously to those of the inlet lock  9 . The transporting device also has a guiding roller  46  which is arranged behind the deviating roller 45  for deviation of the product web  1  and for separation from the sieve band  41 , and a supply band  47  for supplying the product web  1  to the device  6 . The supply band  47  which is guided over the rollers  48 ,  49  runs in this example horizontally and extends to underneath of the pre-chamber  37  of the inlet lock  9 .  
         [0044]    For printing, the product web  1  is pulled from the product storage  2  over the supply device  3  formed as boom and through the printing device  40  formed as a rotary printing press to the device  6  for dye fixing.  
         [0045]    The product web  1  is transported over the supply band  47  of the transporting device to the under the pre-chamber  37  of the inlet lock  9 . Their the sieve band  41  takes over the transportation from below to the pre-chamber  37 , through the gap  35  into the main chamber  37 , around the deviating roller  42 , through the inlet slot  37  and through the treatment chamber  12 . For this purpose the product web  1 , for example automatically is clamped on the sieve band. The product web  1  leaves the device  6  through the outlet slot  29  and the outlet lock  11 . It is supplied over the supply device  7  which is formed as a taking off table to the product storage A which is formed as a container. The product web speed amounts for example from 40 m/min.  
         [0046]    In the printing device  40  the product web I is provided with printing paste. The moist product web  1  during its transportation flatly through the treatment chamber  12  of the device  6  is acted upon by hot steam from the nozzle boxes  15  arranged above and below the product web  1  and having nozzle openings oriented toward the product web. The nozzle pressure amounts to 200-1000 PA and a thermal transmission power is substantially 240 W/m 2 .  
         [0047]    The temperature of the hot steam amounts to 1300 in particular 160° to 230° C., and the retention time of the product web  1  in the treatment chamber  12  amounts to 5-60 seconds, preferably 10-20 seconds. The residual moisture of the product web  1  when it leaves the housing  10  amounts during printing to less than the equilibrium moisture under normal conditions, or in other words it is smaller than 10%.  
         [0048]    In the treatment chamber  12  and in the main chamber  36  the inlet and outlet locks  10 ,  11  are maintained with a slight overpressure. The steam content, preferably between 95 and 100 vol. percent, is maintained by changing of the quantity of the aspirated hot steam, through the suction passages  38  of the pre-chambers  37  of the input and outlet locks  9 ,  11 . A regulation of a predetermined residual moisture of the product web  1  is not needed.  
         [0049]    In an example of the printing process, a product web  1  of cotton with applied printing paste as reactive dye without urea with a product web weight 80 g/m 2  is transported with a product web speed of 40 m/man through the device  6 . The temperature of the pure hot steam amounts to 100° C. The nozzle pressure at the nozzle openings of the nozzle boxes  15  amounts to 700 PA. After a retention time of 5 seconds the overwhelming part of the dye is reacted with the fibers of the product web  1  and is fixed. After further 5 seconds, the product web  1  is completely dried and the residual part of the dye is fixed. The initial moisture is reduced by approximately 20% in the device  6  to a value smaller or substantially equal to 5%. The total retention time in the device  6  amounts to 10 seconds. In the embodiment shown in FIG. 3, the device  6  for dye fixing corresponds to the previously described device. Three treatment chambers  12  are arranged in the housing  10 . Each treatment chamber  12  is provided with a circulating fan  14  and an upper and a lower nozzle cast  15 .  
         [0050]    The transporting device also has a circulating conveyor formed as a sieve band  51 , which in contrast to the first example is guided over two deviating rollers  52  and  53  with its upper and with its lower run through the treatment chambers  12 . In other words the conveyor is supplied back through the treatment chambers  12 . Also the deviating roller  52  is located completely in the inlet lock  9  and the deviating roller  53  is located completely in the outlet lock  11 . Their arrangement is such that the product web  1  is guided in a horizontal transporting plane. The deviating roller  53  in the output lock  11  is connected with a not shown drive. In the outlet lock  11   a  not shown tensioning device for the conveyor is located.  
         [0051]    The transporting device is also provided with transporting rollers  54  in the field abutments, or in other words in the regions in which the treatment chambers  12  abut against one another.  
         [0052]    The input lock  9  of this device  6  for dye fixing extends at an acute angle to a vertical. For this purpose the front plate  31  is arranged at this acute angle to the vertical and the not shown side plates are correspondingly shaped. The intermediate plate  34  extending from the front wall  26  is extended in correspondence with the deviation of the plate  31  and has at least front end such an edge  55  that it ends opposite to the intermediate plate  33  extending from the front plate  31 . Also, the nozzle box  39  extending from the front wall  26  is correspondingly elongated and edged.  
         [0053]    The transporting device has in this example a guiding roller  56  at the outlet of the outlet lock  11  and a supply band  57 . The supply band  57  is guided over two rollers  58 ,  59 , extends parallel to the front plane  31  and extends through the front chamber  37  and the main chamber  36  of the inlet lock  9 . In other words the supply band  57  forms a guiding band which runs at an acute angle to the vertical through the inlet slot  9 . The gap  35  between the intermediate plates  33 ,  34  and the distance between the suction boxes  39  is formed correspondingly wide. The upper roller  59  of the supply band  58  is arranged substantially before and substantially above the deviating roller  52  and the roller  56  before the pre-chamber of the input lock  9 .  
         [0054]    During printing, the moist product web  1  provided with the printing paste is transported over the supply band  57  through the inlet lock  9 , placed on the sieve band  51  from above and transported on the sieve band  51  through the treatment chambers  12  to the outlet lock  11 . From the outlet lock  11 , the product web  1  is withdrawn over the guiding roller  57 .  
         [0055]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.  
         [0056]    While the invention has been illustrated and described as embodied in METHOD OF AND DEVICE FOR CONTINUOUS TREATMENT OF A TEXTILE PRODUCT WEB WITH STEAM FOR FIXING REACTIVE DYE ON NATURAL FIBERS, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0057]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.