EP0385182A1 - Method for producing a mixed yarn - Google Patents

Abstract

The invention relates to a method for producing a mixed yarn from cotton fibres and chemical fibres. …<??>In conventional methods, the mixing of cotton and chemical fibres has hitherto been carried out after the process of combing the cotton. To obtain an appropriate yarn quality, it is necessary to comb out the cotton and at the same time separate the short fibres. …<??>In the previous method of bringing the mixture components together after the combing process, there were problems as regards a homogeneous mixing of the cotton and chemical fibres. A high mechanical outlay was needed for this. There is therefore provided a method in which the two mixture components (A,B) of cotton and chemical fibres are brought together (18) even before the combing operation (5) and are subsequently combed together. This provides a homogeneous mixture and a reduction of the mechanical outlay. …<IMAGE>…

Description

The invention relates to a method for producing a mixed yarn from cotton and man-made fibers. To achieve a fine yarn quality, it is necessary to comb out and separate the short fibers of the cotton in a combing process. This applies to a high quality pure cotton yarn as well as a so-called blended yarn, whereby another fiber material is also spun.

Conventional blending methods are known in practice, the blending of cotton and man-made fibers being carried out on a blending line following the combing process of the cotton. The combed cotton fiber tapes are doubled with the carded fiber tapes made of man-made fibers and possibly passed through a route passage and stretched and combined into a single fiber tape in the drafting system. The sliver discharged from the mixing section, which is now composed of cotton and man-made fibers, is usually passed over two further subsequent drafting units in order to obtain a good mixing of the cotton with the man-made fibers while simultaneously paralleling the fibers, in accordance with the doubling carried out in the process.

However, it has been shown that the effort involved in the known solutions for machine use, in particular on route passages, is relatively high in order to achieve a homogeneous distribution of the cotton and chemical fibers in the sliver, especially since it is difficult to mix the elastic synthetic fibers with the smooth cotton . However, this homogeneous division is necessary for the subsequent spinning process and ultimately for the quality of the yarn. In addition, the mixing has an influence on the hairiness, the splicing and the fiber structure of the finished yarn.

It is therefore the object of the invention to propose a method whereby a desired good blended yarn quality is achieved, taking into account a reduced machine use.

This object is achieved in that the cotton and man-made fibers, which are combined to form a mixture, are combed together, drawn and then spun into a yarn.

It is further proposed to mix the cotton and chemical fibers in a mixing plant, the resulting mixture being carded and then doubled and stretched. The slivers formed are combined on coils and are sent to the combing machine to be combed out. After combing, only a subsequent stretch is required for doubling or stretching, before the sliver that is released in the process is discharged to the spinning machines for spinning.

Furthermore, a method is proposed, in which separately carded cotton fiber tapes and chemical fiber tapes are brought together on a duplicating and route passage. Wobbles are formed from the mixed fiber tapes thus formed, which are then combed out on the subsequent combing machine.

Here too, after the combing process, only one draw passage for doubling or drawing the combed sliver belts is necessary before the slivers are transferred to the spinning machines. The spinning machines can consist of a roving spinning machine, a flyer and a subsequent ring spinning machine or a rotor spinning machine or other spinning machines processing sliver.

Further advantages are described and shown in more detail using the following exemplary embodiments.

• Figur 1: eine schematische Darstellung eines konventionellen Verfahrens.
• Figur 2: eine schematische Darstellung eines erfindungsgemässen Mischverfahrens.
• Figur 3: eine schematische Darstellung eines weiteren Bei­spieles eines erfindungsgemässen Mischverfahrens.

Show it:

• Figure 1: a schematic representation of a conventional method.
• Figure 2 is a schematic representation of a mixing method according to the invention.
• Figure 3 is a schematic representation of another example of a mixing method according to the invention.

Figure 1 shows a conventional method of combed blended yarns. The combination or the mixing of the cotton and chemical fibers, in the example shown polyester fibers, takes place in a mixing section 9.

However, before the two components of cotton and chemical fibers, e.g. Polyesters are mixed, they are subjected to different and separate processing processes A and B.

In process A, the cotton is presented in flake form by the blowroom 1 to the cards 2 for further processing.

The blowroom 1 generally consists of a bale removal machine for dissolving the cotton bales, a subsequent cleaning machine, an automatic mixer for achieving homogeneous mixing of the fiber material and a further cleaning machine.

For the sake of clarity, these machines have not been shown, especially since they are known machines.

Such machines can also be found in the brochures from Rieter, Winterthur, from the product range for short-staple spinning.

The machine range of the blow room 1 presented could also have a different machine composition or machine sequence.

The cotton fiber sliver released by the card 2 is doubled in a subsequent draw frame 3. The doubling is done four or eight times.

With the sliver leaving the preliminary section 3, 4 coils are formed in the subsequent wadding duplicating machine, which are combed out in the further process on the subsequent combing machine 5. The doubling on the wading doubling machine is e.g. 24-32 times.

The first step in the processing branch B for the polyester is the blow room 6. Here, similar to the production branch A in the blow room 6, the chemical fiber bale supplied is broken up into fiber flakes and presented to a card 7 for further processing. In the card 7, the polyester fibers are completely dissolved up to the individual fiber and aligned in the longitudinal direction and, like the card 2, a sliver is formed. This sliver, which consists of pure polyester, is doubled in a subsequent stretch 8 six to eight times.

The polyester fiber sliver delivered at the feeder 8 is doubled or mixed in a subsequent mixing section 9 with the cotton fiber sliver delivered by the combing machine 5. The duplication is usually done six to eight times.

The sliver leaving the mixing section 9 now consists of the two components of cotton and polyester. In order to achieve sufficient mixing and homogenization of the sliver, the sliver is guided over two subsequent route passages 10, 11. The duplication in these two route passages 10, 11 is generally carried out six times.

Following the second slot passage 11 is a flyer 12, in which a so-called roving is made from the sliver. The roving thus formed is spun into the finished yarn in a subsequent ring spinning machine 13. It is also conceivable to feed the sliver directly from the line passage 11 of a spinning machine, e.g. submitted to a rotor spinning machine for yarn production.

The actual mixing process in this conventional method takes place in the mixing section 9, as well as in the two subsequent section passages 10 and 11. With a duplication number of 8.6 and 6, a total duplication of 288 takes place.

It has been shown in practice that this total duplication is often not sufficient to achieve a homogeneous distribution of the two fiber materials when viewed across the cross section of the fiber sliver. To increase the number of doublings, it would be conceivable to introduce a further stretch of passage, but this further passage of passage entails technological disadvantages, in particular with regard to the adhesive force of the sliver. It has been shown that this conventional method of producing a mixed yarn had reached a limit in terms of yarn quality.

This is where the invention comes in, which is explained using two exemplary embodiments.

A production process is presented in FIG. 2, with both materials, cotton and polyester, as described in the conventional process, going through the cleaning step 1, 6.

The fiber flakes delivered by the blow room 1 and 6 are then mixed in a mixing system 14, a so-called flake mixer. The proportions of the mixture the cotton or polyester can be selected as desired. The flake mixture is fed to a card 15 and carded. The card clothing is set so that both mixture components are taken into account. Compromises may be necessary.

The sliver released by the card 15 is doubled four to eight times in a subsequent draw frame 16. As in the conventional method, the doubled sliver is processed into coils in a subsequent wadding doubler 4. The rolls, which consist of a homogeneous mixture of cotton and polyester, are applied to the subsequent combing machine 5 for combing out. This combing process essentially involves combing out and removing the short cotton fibers. The proportion of short polyester fibers, which is also combed out, is very low and depends directly on the proportion of short fibers in the preliminary processes.

The technology of today's combing machines ensures that no long fibers are combed out, which means there are no losses when combing out the polyester content. The process of combing out a cotton / chemical fiber blend results in a shortening of the process in terms of machine use and increased yarn quality and thus a more economical manufacturing process.

As a result of the intensive mixing of cotton and polyester fibers, it is possible to switch on from one route section 17 after the combing process.

The sliver discharged from the route passage 17 reaches a flyer 12 and a subsequent ring spinning machine 13, as previously described, where the yarn is finished.

If one now compares the mixing or doubling of the two components of the mixture with the conventional method, it must be noted that the doubling in the new method is significantly higher. Assuming a doubling of 6 for the preliminary section 16, 30 for the wading doubling machine 4, 8 for the combing machine 5 and 8 for the section passage 17, the total doubling is 11,520. This comparison alone shows that a significantly higher degree of mixing can be achieved with regard to the mixing of the two components with the conventional method. The mixing of the two components already in the flake form in the mixing system 14 results in an extraordinarily homogeneous distribution over the sliver cross section.

FIG. 3 shows a further exemplary embodiment, the cotton in flake form being delivered to a carding machine 2 for further processing after the blow room 1. The chemical fiber, e.g. the polyester, also comes in flake form after the blow room 6 to a card 7, where a polyester sliver is formed.

The combination of cotton and polyester takes place after card 2 and 7, the sliver being dispensed and carded being combined and doubled in a mixing section 18. The further processing method for the fiber sliver discharged from the mixing section 18 corresponds to the method already described and followed in FIG. 2 after the preliminary section 16. This means that the mixing section 18 is followed by a wadding duplicating machine 4, a combing machine 5, a stretch passage 17, a flyer 12 and a ring spinning machine 13. An overall duplication is also achieved in the embodiment shown in FIG. 3, which corresponds to that in the embodiment in FIG.

In the example in FIG. 3, cotton and polyester are brought together in the form of carded fiber tapes. The mixing of the two components in the form of flakes (Figure 2) results in better mixing, but compromises in the choice of the clothing and in the setting of the card clothing must be accepted if both materials are processed simultaneously on the same card.

This disadvantage is eliminated in the method according to FIG. 3, in that both the cotton and the polyester are processed with a special card clothing geared to the material. This means that no compromises are necessary with regard to the setting and production of the cards.

The method proposed according to the invention, in which the cotton portion and the polyester portion are brought together before the combing process and then combed together, can on the one hand achieve a homogeneous yarn in the mixture and on the other hand achieve a reduction in the required machine units. As can be seen from the examples shown, 13 machine units are necessary in the conventional method and only 10 machine units in the method according to the invention.

With regard to the wadding duplicating machine 4, another known method with a wadding machine and a subsequent sweeping section can also be used (Rieter E 2/4 A and E 4/1 A).

Claims (5)

1. A process for producing a mixed yarn from cotton and man-made fibers, characterized in that the cotton and man-made fibers, which are combined to form a mixture, are combed together, drawn and then spun into a yarn. 2. The method according to claim 1, characterized by the following process steps: a) Mixing the cotton and chemical fibers in a mixing plant b) carding the mixture c) Doubling and stretching of the carding tape d) Formation of wraps e) combing the wraps f) stretching or doubling of the sliver bands g) spinning the drawn fiber slivers 3. Device according to the method of claim 2, characterized by the following machine combination: a) Flake mixing machine for cotton and chemical fiber flakes b) Card c) Advance route d) wadding machine e) combing machine f) Follow-up route g) spinning machine 4. The method according to claim 1, characterized by the following process steps a) Carding the cotton b) Carding the chemical fibers c) Merging the carded cotton and the carded man-made fiber tapes on a duplicating and stretching passage. d) Formation of wraps e) combing the wraps f) stretching or doubling of the sliver bands g) spinning the drawn fiber slivers 5. The device according to the method of claim 4, characterized by the following machine combination: a) Card for cotton a1) Card for man-made fibers b) merging the slivers of a and a1 in a mixing section c) wadding machine d) combing machine e) Follow-up route f) spinning machine

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