Method and device for fibrillating easily fibrillated cellulose fibres, particularly tencel fibres

The invention relates to a method and apparatus according to the preamble of the independent claims.

Fibrillatable cellulose fibers, in particular Lyocell fibers (As Tencel fibers) are very successful due to good dyeing and Wearing properties and a variety of equipment options and method for influencing the "handle" increasing popularity.

"Lyocell" fibers are in a solvent-spinning process made cellulose fibers, whose sheath by mechanical Influence is cleavable so that the jacket surface Fibrils protrude.

Customary in lyocell fibers it is in fibrillation initiate the rope treatment. Factors that tilt the influence to fibrillation are mainly: pH, Temperature and mechanical action. In addition to commonly used cellulase enzymes to the fibrillation to promote. Cellulase enzymes are protein substances that are capable of degrade cellulose. A cellulase enzyme consists of a Variety of different enzyme components. The 4 main are: endo, exocellulase, cellobiohydrolase and cellobiase. The resulting action of exocellulases in soluble glucose directly from cellulose. The other Components engage systematically to the cellulose chains, by arbitrarily to the formation of soluble cellobiose Glucose columns.

Theoretically, the fibrillation of Lyocell fibers only by mechanical treatment, in particular by Wet friction initiate. The addition of enzyme is an additional Promotion and control of the process. Also Enzyme processes are used according to a first fibrillation to weaken the long fibrils and remove. This process is described in detail in "ITB finishing, 2/94, p.5; R. Breier, finishing lyocell fibers, Fibres / Textile Industry, 44./96. Vintage, November / -December 1994, p 812; Lyocell fibers: preparation, properties, Areas of application in chemical fiber / textile industry, 43./95. Born in October 1993, p 745: I. Marini, Lenzing Lyocell fibers in fibers / textiles, 43./95. Born in November 1993, p 878th

In practice, the fibrillation is usually in the strand treatment initiated and carried out discontinuously. Known fibrillation require many hours Treatment period. In contrast to so far assumed that at the classical form of Finish of Tencel fabric (treatment "Open-wide") no fibrillation occurs.

From EP 535 287 A1 discloses a method and apparatus to grip and surface improvement of textile fabrics known and knitted. The treated web is here alternately to a first and a second baffle thrown. The promotion of the web takes place pneumatically, wherein a feed difference in the back and forth movement results in that the product web from the apparatus is discharged.

From US 4,291,442 it is known to polyester fibers under the influence an alkaline aqueous solution to fibrillate. The Breaking the fibers can occur, for example, that the web through a relatively small opening is forced.

From JP 701566A it is known to fibers by applying fibrillate with a gas stream. JP 1-298273A is also known chemically pretreated cellulosic fibers break.

However, the invention proposes that the fibrillation of fibrillatable cellulose fibers such as Lyocell, in particular of Tencel fiber-containing fabrics with carry out broad commodity. According to the invention, this can be achieved if the wide web by a high with Rate applied flowing liquid stream and from this is accelerated and with the liquid stream against an impact surface is thrown and when the acceleration and centrifuging process is repeated until Surface areas of the fibers being cleaved and forming fibrils.

In a known manner can fibrillation by enzyme treatment, influenced temperature and pH adjustment will. The invention can be dropped to goods primarily to fibrillate and for example in a downstream enzyme process in a known manner the long fibrils by enzyme treatment to remove. The inventive method can also the secondary fibrillation can be used, which means So for a Fibrillierungsprozess, of a first fibrillation, a subsequent treatment for the reduction of to long fibrils and optionally other finishing steps is to appear.

It is particularly advantageous if the web in a Goods storage accumulated and from this through the high Speed ​​flowing liquid is withdrawn. The lying loose in such goods storage goods can particularly by the high velocity are liquid entrained and accelerated.

It is particularly advantageous further if the web sequentially in the opposite direction from such a entrained liquid flow and thrown against baffles becomes. For example it is conceivable that in a gap to promote wide-goods by the liquid flow, to hurl against an impact surface, the goods in a collect goods store, then the liquid flow in the reverse direction and the goods opposite in accelerate direction through the gap and on to a the other side of the gap arranged second impact face hurling and there the goods again in a department store to accumulate. Goods would thus alternately "forward, backward "promoted by the guide gap. If this the Time for promotion in direction is "forward" Greater than the time period for the promotion in the opposite Direction results in a resulting "forward" funding. For example, conveyed in one direction six seconds are, then is switched in, and for only five seconds promoted the opposite direction. After this is again for six promoted seconds forward and five seconds down sponsored etc .. Thus, the product is handled at about ten acceleration processes, wherein they respectively against a baffle plate is thrown.

Specifically recommended accordingly arranging two Goods store, where the goods are accumulated each loose is after they hurled against an impact surface has been. From such goods store can then be the accordingly desired subsets carry away while the remainder for another treatment cycle, that is, acceleration in the opposite direction available again.

Such treatment cycles with wechselweisem Accelerate slings and the goods against baffles leads to particularly good grip properties. Of course, it would be conceivable that goods in one direction by an arrangement to promote and to treat the desired quantity of goods to to repeat the process in the opposite direction.

Particularly good results can be achieved if the Web at a speed of at least 8 m / sec. preferably to a speed of 9 m / sec. to 15 m / sec. is accelerated.

This can be achieved especially when the speed the liquid jet (preferably a water jet) in Conveying gap approximately 12 to 20 m / sec., Preferably about 15 m / sec. is.

The inventive method for fibrillating a textile web contains cellulose fibers, in particular Lyocell fibers (such as Tencel fibers) can be particularly effectively through a device in which a wide supplied web in one of a liquid perfused guide gap is accelerated when the Guide gap at least on one side by a nozzle member is limited, which has a supply channel for the liquid and having the opposite on two sides a become the guiding gap narrowing exit slit and a Valve element for alternately closing one of the having exit slots.

be particularly uniform and good acceleration achieved if both surfaces of the guide slot Discharge gaps are provided for the liquid, so that the product both at the top side and on its underside subjected to acceleration by the liquid is.

Instead of an exit gap for the liquid can be of course also provide several outlet column, provided that this favorable flow values ​​with itself brings. In practice, it has proven particularly useful when each outlet gap towards the guide gap to tapers and when the flow axis of the exit gap about α at an angle of 10 ° to 20 °, preferably from about 15 ° to the guide gap plane is inclined.

The invention is in the following in exemplary embodiments explained in more detail with reference to the drawings. Show it<dl tsize="6"><dt>Fig. 1</dt><dd>a schematic representation of a fibrillated Tencel fiber as an example of a fibrillated Cellulose fiber,</dd><dt>FIG. 2</dt><dd>the schematic representation of a fabric run with the features of the invention,</dd><dt>Fig. 3</dt><dd>a sectional view of a guide gap for accelerating the web with the features of the invention, and </dd><dt>Fig. 4</dt><dd>the partial representation of the guide slot according to FIG. 3 in a view from the direction "A" according to FIG. 3.</dd></dl>

Fig. 1 shows schematically a Tencel fiber 1 of which Fibrils 2 protrude. The Tencel fiber 1 is part a fabric not shown that an inventive Was subjected to treatment.

As shown schematically in Fig. 2, a web 3 an apparatus for fibrillating 4 via a feed roller 5 supplied from a conveyor device, not shown. The feed roller 5 continuously promotes the web in a Goods storage 6. From there, the web 3 passes through the Guide gap 7 an acceleration device. 8

The guide slot 7 is lower by an upper and a Guideway 9a and 9b limited. In the lower track laterally two exit slots provided 10 wherein each of the column through valve means 11 closable is. In the embodiment shown in FIG. 2 is the Exit slot 10 a closed, while the outlet gap 10 b opened while according to the embodiment Fig. 3 of the exit slit 10 b shown as closed is. The exit slit of water occurs at a rate of about 15 m / sec. from that of a supply line 12 is supplied. The outlet from the column 10 b water flowing tears the web 3 with, it accelerates and hurls against an impact surface 13, whereby the Web 3 and the fibers constituting the web 3, subjected to mechanical strain. falls from the baffle 13 the web down into a merchandise store 17 from which they can be transported away by conveying rollers 14 and 15. FIG.

To the web 3 multiply the treatment described suspend, can the valve means to move laterally, so that alternately the exit slots 10a or the will exit slots 10 b closed. Depending on by which exit slit the liquid at high speed outlet, the material web 3 is either against the baffle 13 or thrown the baffle 16th The reciprocal Skidding causes particularly uniform and the handle of the product effective mechanical treatment of the web.

Fig. 3 shows an embodiment in which a guide gap 7 on both the upper side and on the underside of the web 3 with exit slits 10 a, 10 b, provided is. Accordingly, two valve means 11 are provided, which in the illustrated mode, the exit slots 10 b closing, so that the liquid to Exit slits 10 a is supplied and the goods in the direction the arrow is x promoted and accelerated.

Fig. Figure 4 shows in cutting a plan view showing the guide gap 7 according to FIG. 3, through which the web 3 by transported the extracted at high speed water becomes. The exit slots 10a and 10b are on both sides indicated by dashed lines. (As stated above, is when Embodiment of FIG. 2 only on the bottom of Guide slot 7 an outlet opening 10 a provided).

By the number of treatment steps (spin on a Impact surface), the regulation of the impact velocity, by unilateral or reciprocal treatment can be in the invention, the degree of fibrillation and thus also the affect surface finish and feel of the fabric. Upstream and downstream or enzyme treatment steps can be used to determine the fibrillation additionally influence.

Especially in the case of an arrangement according to FIG. 3, in which both at the top of the guide slot 7 and at the bottom the guide slot 7 exit slits 10 a and 10 b for the liquid are provided, is not only "open wide" treat goods but also tubular fabric, provided that this it is asked for. This leads to extremely economical Results, wherein, surprisingly, a surface treatment also occurs inside the tube, although this does not come directly to the baffle in contact. The Treatment generally consists of three components: (1) substance-baffle; (2) Substance-water; (3) fabric material.

The force with which the wet goods against the baffles is flung depends Evidently, both the Speed ​​of the conveying fluid, as well as the length of the Acceleration path, any braking effect and the Mass the wet goods from the moment of impact. Typically occur upon impact forces per centimeter width in the goods Magnitude 2.5 to 9 Newtons. are Preferably the values ​​between 5 and 9 Newtons per cm. this leads to particularly good Fibrillierungsergebnissen.

Particularly effective is the invention when used with tissues, the entirely of fibrillatable cellulose fibers, such as "Lyocell" fibers (in particular Tencel fibers) are made. It but it is also possible to treat product, the mixed fiber or blend fabrics composed.