EP0234170B1 - Method for spinning flax or mixtures thereof - Google Patents

Abstract

1. Process for spinning pure or blended flax, designed for the textile industry to form a yarn by twisting flax fibres from bundles of long fibres swingled and agglomerated by pectins, implementing at least one spinning frame, characterized in that : - the length of the fibres is mechanically reduced by a suitable treatment, followed by another mechanical operation so as to obtain only short, extremely fine fibres, - the short fibres are carded to form a ribbon, - the ribbon is drawn to adjust its weight per unit length and the said short fibres are controlled while they are being drawn on the spinning frame, - the ribbon is twisted to form a roving, - the roving is wetted, - the wetted roving is drawn and is twisted to form the yarn.

Description

The invention relates to a process for spinning linen. It will find its application in particular in the textile industry for the production of spools of pure linen thread or in mixture with other natural, artificial or synthetic fibers.

Since ancient times, flax has been cultivated for its textile fibers and its seed which provides a drying oil. He claims deep, fertile land rich in humus, which has localized his culture in certain regions of the world in particular, the USSR, China and Northern Europe.

The flaxseed harvest is done during the summer. The stems are torn off and subjected to retting and scutching operations.

In the stem, the elementary fibers with an average length of 2 to 3 cm and an average diameter of 13 to 15 microns, are agglutinated to each other by a pecto-woody complex, to constitute the fibrous bundles. These are located at the periphery of the stem, in the Liberian zone and, at maturity, are strongly adherent to the central woody trunk.

Retting is a biological operation, the main purpose of which is to separate the fibrous bundles from the woody trunk. There is retting on the ground and retting with water. When retting on the ground, at the time of uprooting, the stems are spread out on the ground and they remain there for 3 to 6 weeks. Under the effect of humidity and temperature, saprophytic fungi present on the plant at the time of uprooting, proliferate and secrete enzymes which partially dissolve pectic cements welding the fibers to the wood.

The main role of scutching is to separate the fibers from the wood. For this, the stems undergo the crushing operation which breaks the wood while leaving the fibers intact, then they are beaten to make the shives fall or woody debris. The useful product is flax or flax; but one of the by-products also has a textile value: these are the weaving tows, more or less short fibers, separated from the dyed flax during threshing.

Dyeed flax, the apparent length of which is generally between 70 cm and 1 meter, consists of bundles adhering to each other longitudinally and transversely. In fact, the dyed flax delivered to the spinning machine, corresponds to the entire fibrous corona of the Liberian zone in which the elementary cellulosic fibers represent only 70% by weight, the rest being non-cellulosic substances decomposing into hemicelluloses, pectic materials, lignins and mineral elements.

It is this particular fibrous morphology which makes the work of linen very specific and at the very least difficult and expensive compared to that of other well known fibers such as cotton, wool and synthetic fibers.

Among the known spinning processes, dyed flax undergoes the combing operation, the role of which is threefold: to clean the tow by ridding it of the last traces of shives; separate the bundles linked together by the cortex and cortical parenchyma and thereby refine the technical fibers; eliminate the short fibers of the foot and head that are the combs.

This already particularly expensive operation, has the additional disadvantage of being carried out on a heavy machine, not very productive and of almost century-old design. This machine known as a large combing machine is very expensive to buy since it is large and performs repeated alternative operations.

The resulting combed linen is spread out and the tablecloth thus obtained is stretched to provide a continuous ribbon.

This is stretched and doubled successively on 5 machines called drawing benches whose role is threefold: to improve the mass regularity of the ribbon as much as possible; gradually reduce its linear density (or title); refine the technical fibers by cleaving the fibrous bundles. This third function, which is fundamental to allow suitable spinnability, is obtained by stretching the ribbon in a field of increasingly fine needles by means of a stretching train (steel-wood) working in a thin layer.

This operation in known processes is carried out on very specific equipment with a particularly high purchase price.

The ribbon emerging from the last pass is then stretched on a spindle bench, which is also very specific and very expensive, in order to obtain a slightly twisted wick intended to be worked on a spinning loom.

To make a fine wire, it is essential that the constituent fibrous elements are themselves very fine and close to the elementary fiber. However, the fibrous elements making up the unbleached wick have an average length of between 15 and 20 cm and often have between 3 and 10 elementary fibers in section. It is therefore necessary to dissociate the elementary fibers during the spinning operation or before it.

To do this, the unbleached wick was wet for a long time by passing it through a tank of water brought to a temperature of about 70 ° C. and drawing it in a rolling train with fluted rollers, at high pressure and with spacing between 65 and 80 mm. But this way of proceeding leads to very difficult working conditions and does not allow obtaining thinner yarns than Nm 21 (48 tex) validly marketable.

For two decades, the industrial spinning of flax in the wet has been carried out from wicks having undergone a chemical treatment of leaching or bleaching. The elementary fibers thus chemically treated, are partially separated and it is then possible to spin with cold water and to make finer, more regular and stronger threads. However, in addition to its advantages, such a treatment has a certain number of drawbacks: it is expensive, causes a loss of material on the order of 10% and does not always allow a constant shade to be obtained.

Furthermore, the production of mixed yarns is rather the result of dry spinning, which does not easily allow the production of majority fine yarns in flax, especially in short fibers.

In short, all the current flax spinning processes used industrially, have serious disadvantages: either they are very limited in spinnability and do not allow the production of fine yarns, or else obtaining fine quality yarns is not possible only by implementing expensive transformation processes with reduced productivity.

The main object of the present invention is to present a very economical method of spinning flax. The substantial gains that can be made are in terms of reduced labor and also in terms of investment in equipment.

Indeed, according to the invention, a large number of handling operations can be eliminated thanks to the use of highly productive machines such as are encountered in other sectors of textile activities, such as that of short fiber.

Savings in material can also be made since the invention makes it possible to overcome the needs for machines specific to linen (combing and preparation).

Another object of the present invention is to present a process for spinning flax which makes it possible to obtain a pure flax yarn or a blended yarn of a cleanliness hitherto unequaled industrially, while retaining the appearance of traditional flax.

The raw material used is very short technical flax fiber of variable length and very mechanically refined, for example using an opener (without any chemical or physico-chemical treatment), the length and fineness of which are fairly close to the characteristics of elementary fiber.

The prior shortening is carried out on lengths of the order of 5 to 6 cm and then the material is refined, that is to say that the bundle which initially comprised ten to forty elementary fibers in section is reduced to a fibrous element much finer and comprising only a few elementary fibers.

In the case of production of mixed yarns, another natural fiber or artificial or synthetic fiber is also used, the intimate mixing being carried out at the very start of preparation.

The preparation, i.e. the different physical operations before spinning, is derived from that used for other short fibers such as cotton or other artificial fibers of the same size: card, two drawing passes and bench -to-pin.

The spinning according to the invention, which is carried out after physical preparation, is derived from the conventional spinning of flax in the wet: soaking the wick continuously in water which may be cold; rolling comprising a stretch control system.

Linen fiber has not undergone any chemical or physico-chemical treatment, it is unbleached and therefore has retained a good part of its non-cellulosic constituents: hemi-celluloses and pectic substances.

• - elle n'a pas subi de perte de matière non récupérable importante et conséquemment, son coût est limité,
• - elle est très accessible à l'eau en raison de sa grande finesse et de sa faible longueur et ne nécessite pas de traitement chimique préalable à la filature,
• - elle apporte les ciments pectiques qui, après ramollissement et séchage, contribuent à donner plus de cohésion entre les fibres dans le fil.

It therefore has several advantages:

• - it has not suffered any significant loss of non-recoverable material and consequently, its cost is limited,
• - it is very accessible to water because of its great finesse and its short length and does not require any chemical treatment prior to spinning,
• - it provides pectic cements which, after softening and drying, help to give more cohesion between the fibers in the yarn.

The yarn thus obtained has a real "linen look" even when it is made in a mixture with artificial or synthetic fibers. This is due to the fact that the flax fiber remained unbleached and that it was spun in the wet state.

This gives the yarn a high technological and commercial added value compared to the same yarn produced in the dry state, because the appearance of the yarn obtained by the process of the invention is very similar to traditional flax yarns.

Wet spinning and subsequent drying avoids hot spray fixing which often has to be done when a blended yarn is made in the dry state.

• - l'aspect du fil et sa régularité sont très proches des mêmes caractéristiques du fil classique lin; en propreté, le fil relevant de l'invention est même supérieur car il ne comporte aucun gros défaut,
• - le prix du fil se situe entre celui du fil de lin classique et celui du fil de coton, mais cependant plus proche de celui du fil de coton.

Among the advantages of the process, we can cite:

• - the appearance of the thread and its regularity are very close to the same characteristics of the classic linen thread; in terms of cleanliness, the yarn covered by the invention is even superior because it has no major defects,
• - the price of the thread is between that of the classic linen thread and that of the cotton thread, but however closer to that of the cotton thread.

Other objects and advantages of the present invention will appear during the description which follows which is however given only for information and which is not intended to limit it.

• - on réduit mécaniquement par un traitement approprié la longueur des fibres suivie d'une autre opération mécanique de façon à n'obtenir que des fi- brs courtes et excessivement fines,
• - on carde les fibres courtes pour former un ruban,
• - on étire le ruban afin d'en réguler la masse linéique et on contrôle les dites fibres courtes durant leur étirage sur le métier à filer,
• - on tord le ruban pour former une mèche,
• - on mouille la mèche,
• - on étire la mèche mouillée et on lui donne une torsion pour former le fil.

According to the present invention, the process for spinning pure or mixed flax, intended for the textile industry for the formation of a yarn by twisting the flax fibers, from bundles of long fibers spotted and agglomerated by pectins using using at least one spinning loom, is characterized in that:

• the length of the fibers is mechanically reduced by an appropriate treatment followed by another mechanical operation so as to obtain only short and excessively fine fibers,
• - the short fibers are carded to form a ribbon,
• the ribbon is stretched in order to regulate the linear mass thereof and the said short fibers are checked during their stretching on the spinning machine,
• - the ribbon is twisted to form a wick,
• - we wet the wick,
• - stretch the wet wick and give it a twist to form the wire.

The invention will be better understood on reading the following description accompanied by an appended drawing which schematizes the drawing train of the spinning machine of the present invention.

The present invention relates to a process for spinning pure or mixed flax.

It will in particular find its application in the textile industry for the formation of a thread produced by twist of tangled flax fibers.

The present invention has a large number of advantages, among which there may be mentioned:

The processing cost is greatly reduced compared to that of the traditional process, to the point of approaching that of short fiber spinning.

Combing and specific linen preparation equipment, excessively expensive to purchase, consuming a lot of energy, requiring a great deal of maintenance and requiring a large workforce, is excluded from the circuit covered by the invention. It is replaced by a lighter material, mass produced and requiring reduced labor and maintenance.

The raw material used is short fiber, preferably mechanically refined (without chemical or physico-chemical treatment), the length and fineness of which are fairly close to the characteristics of the elementary fiber. It is unbleached and therefore has not suffered a significant loss and has retained a good part of its non-cellulosic constituents. Consequently, its cost is limited; it is very accessible to water because of its great finesse and its short length and does not require chemical treatment prior to spinning; it provides pectic cements which, after softening and drying, help to give more cohesion between the fibers in the yarn.

The type of preparation used makes it possible to make any mixture of flax and other fibers without any difficulty and the fibrous mixture is very homogeneous.

The flax spinning process, thanks to the stretching system, makes it possible to spin not only pure flax, but also any type of mixture of flax and other fibers. The yarn thus obtained has a real "linen look" as does the canvas or knitting made from this yarn. This is due to the fact that the flax fiber remained natural and was spun in the wet state. This gives the yarn a high technological and commercial added value compared to the same yarn made in the dry state. Furthermore, the yarn obtained has no major defects as opposed to traditional flax yarn.

Wet spinning and subsequent drying avoids fixing by hot spraying, which is often done when a blended yarn is made in the dry state.

According to the flax spinning process of the present invention, one starts from a raw material composed of bundles of dyed flax fibers.

It is flax having been cultivated under traditional conditions, which has undergone a retting then a scutching. The bundles of long fibers are then agglomerated by pectins.

The first operation that these fibers must undergo consists in reducing their length associated with refining. The length of the fibers, which initially is of the order of 70 cm to 1 m, must in fact be reduced by appropriate treatments to a length of short fibers, that is to say substantially of the order of 2 to 5 cm.

This reduction in length is done mechanically by cutting or cracking followed by a process which refines. It is necessary to obtain short and very fine fibers. This first operation does not generally require chemical or physico-chemical intervention. It is indeed necessary that the fiber retains its natural qualities so that the resulting yarn has the "linen character" from the point of view of its appearance and its feel.

The prior shortening is carried out on lengths of the order of 5 to 6 cm and then the material is refined, that is to say that the bundle which initially comprised ten to forty elementary fibers in section is reduced to a fibrous element much finer and comprising only a few elementary fibers.

It is then necessary to perfect the cleaning of the fibers, to parallelize them and to produce a veil then a ribbon. According to the process of the present invention, this is carried out on a high productivity card derived from those used in short fibers. The feeding and unloading of the machine is automatic which minimizes labor costs, contrasting with the high cost of combing practiced in traditional spinning.

The carded ribbon obtained is then grouped with other ribbons and the assembly is then stretched to form a new ribbon whose regularity is improved. In addition, one or more passes can be made to obtain a ribbon of substantially constant linear density.

The ribbon is then stretched and slightly twisted to form a wick. This phase of the process can be carried out on pin banks.

One of the characteristics of the invention is to spin this wick of short fibers in the wet state. To do this, the wick first passes through a water tank which can be cold, integrated into the spinning machine, then it is stretched in a rolling train designed to work this type of material as well as possible.

As described above, working with short fiber flax on a spinning machine requires some precautions. In particular, control of the short fibers is necessary during their passage through the drawing train of the spinning machine.

Figure 1 shows schematically a drawing machine of spinning loom. A spool 1 of a bench bit wick is used to power the drawing train 2 which delivers a wire 3 which is wound around a spindle 4.

According to the invention, the control of the short fibers is achieved by the use of a drawing train 2 with sleeve 5. The drawing train with sleeve in fact makes it possible to guide the short fibers.

The wick undergoes a pre-stretching between the supply cylinders 6 and the sleeves 5 and then a proper stretching between the sleeves 5 and the delivery cylinders 7.

To improve the control of the fibers, the path of these in the drawing train 2 is carried out in an arc.

Claims (6)

1. Process for spinning pure or blended flax, designed for the textile industry to form a yarn by twisting flax fibres from bundles of long fibres swin- gled and agglomerated by pectins, implementing at least one spinning frame, characterized in that:

- the length of the fibres is mechanically reduced by a suitable treatment, followed by another mechanical operation so as to obtain only short, extremely fine fibres,

- the short fibres are carded to form a ribbon,

- the ribbon is drawn to adjust its weight per unit length and the said short fibres are controlled while they are being drawn on the spinning frame,

- the ribbon is twisted to form a roving,

- the roving is wetted,

- the wetted roving is drawn and is twisted to form the yarn.

2. Flax spinning process according to claim 1, characterized in that the flax roving is wetted with cold water.

3. Flax spinning process according to claim 1, characterized in that the short fibres are inspected while they are being drawn on a spinning frame by passing through a drawing train (2) having a sleeve (5).

4. Flax spinning process according to claim 1, characterized in that the unbleached fibres are given length and fineness properties close to those of the elementary fibre.

5. Flax spinning process according to claim 1, characterized by the fact that the length of the fibres is between 1.5 and 5 cm.

6. Spinning process according to claim 1, characterized by the fact that the roving describes an arc of a circle during its passage through the drawing train (2).

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