Process and device for the continuous mercerizing of textile yarns

Abstract

Continuous process for the mercerizing of yarns effected on the yarn in the form of a bundle, introduced into one or more tubular reactors with an ejection nozzle fed as driving fluid under pressure with the mercerizing solution and then drawn in continuous in one or more drawing units.

1 . A mercerization process of yarns comprising one or more treatment steps of the yarn with an alkaline solution, one or more drawing steps of the yarn after the alkaline treatment, one or more aqueous washing and neutralization steps of the alkalinity residue still present in the yarn, characterized in that 
 the process is carried out in continuous on the yarn collected in a bundle ( 4 ) prepared in a section ( 6 ) in which solidarity is conferred between the threads, and subsequently fed with a feeding device ( 10 ),    the bundle of fibers ( 4 ) is introduced for mercerization treatment in the tubular reactor ( 15 ,  85 ) by suction with a venturi nozzle ( 16 ,  86 ′), in which the alkaline mercerizing solution is fed as driving fluid under pressure, entraining with it the bundle of yarn ( 4 ) and reacts, in one or more reactors ( 15 ,  85 ), from which it exits from the lower part, pulled by discharge rolls ( 31 ,  31 ′),    the bundle ( 4 ) is subsequently drawn in continuous in one or more drawing units consisting of gripping and discharge rolls ( 31 ,  31 ′) and drawing rolls ( 32 ,  32 ′), situated downstream, which are rotated at a higher rate than the rolls ( 31 ,  31 ′).    
     
     
         2 . The mercerization process of yarns according to  claim 1 , characterized in that the further treatment steps of mercerized yarns after drawing with process fluids are carried out in continuous, by putting the bundle ( 4 ) in contact with said process fluids in Venturi nozzles ( 41 ,  41 ′, 41 ″), each fed with the process fluid, as driving fluid, entraining with it the bundle of yarn ( 4 ).  
     
     
         3 . The mercerization process of yarns according to  claim 1 , characterized in that, in correspondence with the contracted vein of the ejector  16 , the driving fluid rate is maintained at between 12 and 40 m/sec.  
     
     
         4 . The mercerization process of yarns according to  claim 3 , characterized in that, in correspondence with the contracted vein of the ejector  16 , the driving fluid rate is maintained at between 15 and 20 m/sec.  
     
     
         5 . The mercerization process of yarns according to  claim 1 , characterized in that, in the mercerization reactor ( 85 ), the bundle of threads ( 4 ) passes in sequence through one or more Venturi tubes ( 86 ′, 86 ″, 86 ′″) situated in series along the reactor itself.  
     
     
         6 . The mercerization process of yarns according to  claim 5 , characterized in that, in the mercerization reactor ( 85 ), the pressurized driving fluid stream is subdivided and distributed among the inlets ( 87 ′,  87 ″, . . . ) 
 to gradually increase the volumetric ratio between the volume of treatment fluid fed and the amount of thread being processed in the axial direction.  
 
     
     
         7 . The mercerization process of yarns according to  claim 1 , characterized in that the threads to be treated are fed to a preparation unit ( 6 ) comprising winding devices onto the threads of the bundle ( 4 ), of one or more auxiliary threads ( 5 ) with long coils, with a shed of 300 to 1500 mm, to form a bundle ( 4 ) of threads adhering to each other.  
     
     
         8 . The mercerization process of yarns according to  claim 7 , characterized in that the bundle of threads ( 4 ) consists of from 20 to 200 threads.  
     
     
         9 . A device for the treatment in continuous of yarns with process fluids, particularly for the mercerization of yarns of cellulose fibers, characterized in that it comprises: 
 preparation and feeding means ( 10 ) of the single thread or the bundle ( 4 ) of several threads ( 1 ),    means for treating the yarns comprising one or more tubular reactors ( 15 , 85 ) having at the start a Venturi nozzle ( 16 , 86 ′), fed, as pressurized driving fluid, with the treatment fluid, which sucks and entrains with it the bundle of yarn ( 4 ), with output in the lower part, pulled by discharging rolls ( 31 ,  31 ′).    
     
     
         10 . The device for the treatment in continuous of yarns with process fluids according to  claim 9 , characterized in that the reactor ( 85 ) comprises two or more Venturi tubes ( 86 ′, 86 ″, 86 ′″) situated in series along the axis of the reactor itself.  
     
     
         11 . The device for the treatment in continuous of yarns with process fluids according to  claim 10 , characterized in that the inlets ( 87 ′, 87 ″, 87 ′″) of the pressurized driving fluid in the Venturi tubes ( 86 ′, 86 ″, 86 ′″) are situated at the side, whereas the bundle of yarn ( 4 ) follows, with a straight run, the axis of the sequence of the Venturi nozzles in the reactor ( 85 ).  
     
     
         12 . The device for the treatment in continuous of yarns with process fluids according to  claim 9 , characterized in that the preparation and feeding means of the threads in the bundle ( 4 ) comprise a cable laying funnel ( 3 ) and winding devices onto the threads of the bundle ( 4 ), of one or more auxiliary threads ( 5 ) with long coils, with a shed of 300 to 1500 mm, to form a bundle ( 4 ) of threads adhering to each other.