EP0806512B1 - Method and device for fibrillating easily fibrillated cellulose fibres, particularly tencel fibres - Google Patents

Abstract

Fibrillating a web of textile fabric (3) containing cellulose fibres, particularly Lyocell (RTM) fibres, comprises using a high-velocity stream of fluid impinging on the spread-out web and accelerating it to strike against an impact surface (13, 16). This procedure is repeated as often as needed till the fibre surface regions split and form fibrils. Also claimed is the apparatus for implementing the process of fibrillating web as above, in particular Tencel (RTM) fibres. The web is accelerated by the flowing fluid in a guiding gap (7) which is bounded on at least one side by a jet (9a, 9b, 10a, 10b) which has a fluid feed channel (12) and, on two opposite sides, a nozzle-like gap exit (10a, 10b) which narrows towards the guide gap. There is a valve (11) which closes each of the exits alternately.

Description

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

Fibrillatable cellulose fibers, especially Lyocell fibers (like Tencel fibers) enjoy 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 Manufactured cellulose fibers, the sheath by mechanical Influence is fissile, so from the surface of the jacket Protruding fibrils.

Fibrillation in Lyocell fibers is common the strand treatment. Factors affecting the inclination to influence fibrillation are above all: pH value, Temperature and mechanical impact. Also be Commonly used cellulase enzymes to fibrillate promote. Cellulase enzymes are protein substances that are capable To break down cellulose. A cellulase enzyme consists of one Many different enzyme components. The 4 most important include: endocellulase, exocellulase, cellobiohydrolase and cellobiase. The effect of exocellulases results in soluble glucose directly from cellulose. The others Components systematically attack the cellulose chains, by arbitrarily making the formation of cellobiose more soluble Split glucose.

Theoretically, the fibrillation of Lyocell fibers only by mechanical treatment, especially by Initiate wet friction. The addition of enzyme serves the additional Promotion and control of the process. Furthermore Enzyme processes are used in order after a first fibrillation to weaken and remove the long fibrils. This process is described in detail in "ITB finishing, 2/94, p. 5; R. Breier, finishing Lyocell fibers, Chemical fibers / textile industry, 44./96. Vintage, November / December 1994, p. 812; Lyocell fibers: manufacture, properties, Areas of application in chemical fibers / textile industry, 43./95. Volume, October 1993, p. 745: I. Marini, Lenzing Lyocell fibers in chemical fibers / textile industry, 43./95. Volume, November 1993, p. 878.

In practice, fibrillation is mostly used during strand treatment initiated and carried out discontinuously. Known fibrillation processes take many hours Duration of treatment. In contrast, it has previously been assumed that the classic shape of the finish of Tencel fabric (treatment "open-wide") no fibrillation occurs.

EP 535 287 A1 describes a method and a device for improving the grip and surface of textile fabrics and knitted fabrics. The web to be treated will be alternating against a first and a second baffle hurled. The web is conveyed pneumatically, with a feed difference in the back and forth movement causes the web from the device is dissipated.

From US 4,291,442 it is known to influence polyester fibers to fibrillate an alkaline aqueous solution. The The fibers can be broken open, for example, by that the web of goods through a relatively small opening is forced.

From JP 701566A it is known to act on fibers to fibrillate with a gas stream. From JP 1-298273A it is also known, chemically pretreated cellulose fibers to break up.

However, the invention proposes fibrillation of fibrillatable cellulose fibers such as Lyocell, in particular from Textile fabrics containing Tencel fibers carry out wider goods. This can be done according to the invention if the wide web is reached by a high one Velocity flowing fluid flow and accelerated by this and countered with the liquid flow an impact surface is thrown and if the acceleration and the spinning process is repeated until Surface areas of the fibers are split and up Form fibrils.

In a known manner, fibrillation by enzyme treatment, Temperature and pH adjustment affected become. The invention can be used to primary goods fibrillate and e.g. in a downstream enzyme process the long fibrils in a known manner by enzyme treatment to remove. The method according to the invention can also be used for secondary fibrillation is used, that is for a fibrillation process that is a first fibrillation, a subsequent treatment to reduce the too long fibrils and possibly other equipment steps after is switched.

It when the web in one is particularly advantageous Store accumulated and from this through the high Speed flowing liquid is withdrawn. The Goods lying loose in such a store can particularly well thanks to the high-speed flow Liquid is carried away and accelerated.

It is also particularly advantageous if the material web is sequential in the opposite direction from such Liquid flow entrained and thrown against impact surfaces becomes. So it is e.g. conceivable that in a gap promote wide-ranging goods through the flow of liquid, hurling against a baffle, the goods in one Collect goods store, then the liquid flow in the Reverse direction and the goods in the opposite Accelerate direction through the gap and up against one the other side of the gap arranged second baffle to hurl and there the goods back in a store accumulate. The goods would alternate "forward and backwards "through the leadership gap Duration for funding in the "forward" direction is longer than the length of time for promotion in the opposite Direction, there is a resulting "forward" funding. For example, can be conveyed in one direction for six seconds then it is switched and in for just five seconds promoted the opposite direction. After that, again for six Conveyed seconds forward and five seconds backwards conveyed, etc. The goods go through about ten acceleration processes, each against a baffle is thrown.

Accordingly, it is advisable to arrange two Goods store in which the goods are loosely accumulated is thrown after hitting a baffle has been. The goods can then be stored in such a store remove the desired quantities while the rest for another treatment cycle, that means acceleration in the opposite direction is available again.

Such treatment cycles with alternate acceleration and hurling the goods against impact surfaces leads to particularly good grip properties. Of course it would be conceivable, the goods only in one direction by an arrangement to promote and after treatment of the desired amount of goods Repeat the process in the opposite direction.

Particularly good results can be achieved if the Goods 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 of the liquid jet (preferably a water jet) in the Conveying gap about 12 to 20 m / sec., Preferably about 15 m / sec is.

The inventive method for fibrillation in a textile web containing cellulose fibers, in particular Lyocell fibers (such as Tencel fibers) can be particularly perform advantageously with a device in which a wide feed web in one of a liquid through the guide gap is accelerated when the Guide gap at least on one side through a nozzle element is limited, which is a feed channel for the liquid and the one on two opposite sides outlet gap narrowing towards the guide gap and a Valve element for alternately closing one of the Has exit column.

Let especially uniform and good acceleration values reach out when in both surfaces of the guide gap Outlet gaps for the liquid are provided so that the goods on both the top and bottom exposed to acceleration from the liquid is.

Instead of an exit gap for the liquid, of course, also provide several exit gaps, provided that this has favorable aerodynamic values brings. In practice, it has proven particularly useful if each exit gap towards the guide gap tapered and if the flow axis of the exit gap approximately at an angle α of 10 ° to 20 °, preferably about Is inclined 15 ° to the level of the guide gap.

Fig. 1

eine schematische Darstellung einer fibrillierten Tencel Faser als Beispiel für eine fibrillierte Cellulose Faser,

Fig. 2

die schematische Darstellung eines Warenlaufs mit den Merkmalen der Erfindung,

Fig. 3

eine Schnittdarstellung durch einen Führungsspalt zum Beschleunigen der Warenbahn mit den Merkmalen der Erfindung, und

Fig. 4

die ausschnittsweise Darstellung des Führungsspalts gemäss Fig. 3 in der Ansicht aus der Richtung "A" gemäss Fig. 3.

The invention is explained in more detail below in exemplary embodiments with reference to the drawings. Show it

Fig. 1

1 shows a schematic representation of a fibrillated Tencel fiber as an example of a fibrillated cellulose fiber,

Fig. 2

the schematic representation of a goods run with the features of the invention,

Fig. 3

a sectional view through a guide gap to accelerate the web with the features of the invention, and

Fig. 4

3 shows a detail of the guide gap according to FIG. 3 in the view from the direction "A" according to FIG. 3.

Fig. 1 shows schematically a Tencel fiber 1 of which Protruding fibrils 2. Tencel fiber 1 is a component of a fabric, not shown, that one according to the invention Has undergone treatment.

As shown schematically in FIG. 2, a material web 3 a device for fibrillation 4 via a conveyor roller 5 supplied by a conveyor, not shown. The conveyor roller 5 continuously conveys the web into one Goods store 6. From there, the web 3 passes through the Guide gap 7 of an acceleration device 8.

The guide gap 7 is formed by an upper and a lower one Guideway 9 a and 9 b limited. In the lower guideway two exit gaps 10 are provided on the side, wherein one of the gaps can be closed by valve means 11 is. 2 is the Exit gap 10 a closed during the exit gap 10 b is open, while in the embodiment according to Fig. 3, the outlet gap 10 b shown as closed is. Water flows through the outlet gap at a speed of about 15 m / sec. from that of a feed line 12 is supplied. That from the exit column 10 b flowing water entrains the web 3, accelerates it and hurls it against a baffle 13, causing the Web 3 and the fibers from which web 3 is made, be mechanically stressed. From the baffle 13 falls the web down into a goods store 17, from which it can be transported away by conveyor rollers 14 and 15.

To the web 3 multiple times the treatment described the valve means can be moved laterally, so that alternately the exit columns 10 a or the Exit columns 10 b is closed. Depending on what outlet gap the liquid is at high speed emerges, the web 3 is either against the impact surface 13 or the impact surface 16 flung. The mutual Skidding is particularly uniform and for the handle of the goods effective mechanical treatment of the web.

Fig. 3 shows an embodiment in which a guide gap 7 on both the top and bottom the web 3 with exit gaps 10 a, 10 b, provided is. Accordingly, two valve means 11 are also provided, the exit columns in the operating state shown Close 10 b so that the liquid Exit columns 10 a is fed and the goods in the direction of the arrow x is promoted and accelerated.

Fig. 4 shows a top view of the guide gap 7, according to Fig. 3, through which the web 3 through which transports water at high speed becomes. The exit gaps 10a and 10b are on both sides indicated by dashed lines. (As stated above, the 2 only on the underside of the Guide gap 7 provided an outlet opening 10 a).

The number of treatment steps (spinning on one Impact surface), the regulation of the impact speed, by one-sided or mutual treatment in the invention, the degree of fibrillation and thus the Affect surface quality and the feel of the goods. Upstream and downstream enzyme treatment steps can be used to fibrillate to influence in addition.

Especially with an arrangement according to FIG. 3, in which both on the top of the guide gap 7 as well as on the bottom of the guide gap 7 exit columns 10 a and 10 b for the liquid are provided, can not only "open width" Treat goods but also tubular goods, if this it is asked for. This leads to particularly economical Results, surprisingly, a surface treatment also occurs inside the hose, although this does not come into direct contact with the impact surface. The Treatment generally consists of three components: (1) fabric baffle; (2) fabric water; (3) fabric-fabric.

The force with which the wet goods hit the impact surfaces thrown obviously depends on both Velocity of the conveying liquid as well as the length of the Acceleration path, any braking effects and the mass wet goods at the moment of impact. Typically In the event of an impact, forces per centimeter of fabric width occur Of the order of 2.5 to 9 Newtons. Preferably lie the values between 5 and 9 Newtons per cm. this leads to particularly good fibrillation results.

The invention is particularly effective when used with fabrics, which are made entirely of fibrillatable cellulose fibers, such as "Lyocell" fibers (especially Tencel fibers) exist. It but it is also possible to treat goods made from mixed fibers or blended fabrics.

Claims (9)

1. A method of fibrillating fibrillatable cellulose fibres contained in a textile fabric web (3), in particular Lyocell fibres, characterised in that the spread-out fabric web is acted upon and accelerated by a fluid flow flowing at high speed, that the accelerated fabric web is flung by the fluid flow against an impact surface (13, 16), and that the accelerating and flinging procedure is repeated until surface regions of the fibres are split and fibrils are formed.
2. A method according to claim 1 characterised in that the fabric web (3) is assembled in a fabric storage means (6) and is then fed to the fluid flow.
3. A method according to claim 1 or claim 2 characterised in that the fabric web (3) is guided by the impact surface (13) to a second fabric storage means (17) and accumulated therein, that then the fabric web is withdrawn from the second fabric storage means (17) by a fluid flow flowing in the opposite direction and is conveyed back into the first fabric storage means (6), wherein the fabric web (3) is accelerated by the fluid flow flowing at high speed and flung against a second impact surface (16).
4. A method according to claim 2 or claim 3 characterised in that the fabric web (3) is conveyed to and fro alternately between the two fabric storage means (6, 17) by an alternating fluid flow and in that movement is flung respectively against impact surfaces (13, 16).
5. A method according to claim 4 characterised in that fabric (3) is additionally continuously fed to the first fabric storage means (6) and that fabric is continuously removed from the second fabric storage means (17) and that, in the case of predetermined conveyor and acceleration steps, a longer fabric web (3) is conveyed into the second fabric storage means (17) than is conveyed back into the first fabric storage means (6) in the subsequent acceleration procedure which is directed in opposite relationship.
6. A method according to one of the preceding claims characterised in that the fabric web is accelerated to a speed of at least 8 m/sec, preferably to a speed of from 9 m/sec to 15 m/sec.
7. Apparatus for fibrillating fibrillatable cellulose fibres contained in a textile fabric web, in particular Tencel fibres, characterised in that a fabric web (3) containing the fibres (1) to be fibrillated is accelerated in a guide gap (7) through which a fluid flows, wherein the guide gap (7) is delimited at least on one side by a nozzle element (9a, 9b, 10a, 10b) which has a feed passage (12) for the fluid and on two opposite sides a nozzle-like discharge gap (10a, 10b) which narrows towards the guide gap (7), and a valve element (11) for alternately closing one of the discharge gaps (10a, 10b).
8. Apparatus according to claim 7 characterised in that discharge gaps (10a, 10b) are provided on both sides of the guide gap (7).
9. Apparatus according to claim 7 or claim 8 characterised in that the discharge gap (10a, 10b) extends at an angle α of from 10 to 25 and preferably from 15° to 20° with respect to the plane of the guide gap (7).

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