JPH0130929B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for producing spun yarn-like yarn from aromatic polyamide fibers.

Aromatic polyamide fibers are superior to ordinary polyamide fibers in terms of rigidity, heat resistance, and other functional aspects, but on the other hand, they have a major drawback in that they are difficult to spin. Aromatic polyamide fibers are currently mainly produced and used as filament yarns or spun yarns produced through a normal spinning process, but depending on the application, spun yarns produced through a simpler process may also be sufficient. There are areas where you can do it. The present invention was made by studying a method for obtaining a useful yarn without difficulty for such purposes, and arriving at the method of the present invention.

That is, in the present invention, when producing yarn from aromatic polyamide fiber, the oil adhesion rate is 0.05 relative to the fiber weight.
After the fibers having a moisture content of ~0.30% by weight and a water content of 7.0% by weight or less are cut into short fibers by a shredding method, the short fiber threads are conjugated in the longitudinal direction while preventing disturbance of the fiber arrangement. This is a method for producing spun yarn-like yarn, which is characterized in that it is made into yarn by spinning.

Aromatic polyamide, so-called aramid, is an excellent fiber that has higher functionality than steel depending on its properties, but if you try to cut it into short fibers by tearing and shredding it into spun yarn-like yarn. There are several problems as described below. This is because staple fiber wraps, slivers, fleece, rovings, etc. expand abnormally during the process, making it difficult to apply drafts, and the process not proceeding smoothly, resulting in frequent yarn breakage, uneven yarn, and poor functionality. This results in a lack of practicality and extremely low productivity.

As a result of various studies on these points, we found that the reason why fibers expand abnormally and cannot be finished is that aromatic polyamide fibers have a very high rigidity, which makes them difficult to bend and lack flexibility. I found out that this is due to this. However, these properties are major features of aromatic polyamide fibers, and it is meaningless unless they are turned into threads without deteriorating these properties. As a result of further investigation, we found that the fibers, which had an oil adhesion rate of 0.05 to 0.30% by weight and a moisture content of 7.0% by weight or less, were cut into short fibers using a shredding method. It has been discovered that the desired spun yarn-like yarn can be obtained without the above-mentioned problems by conjugating the short fiber yarns in the longitudinal direction while preventing disorder of the fiber arrangement. It is something. In other words, in the case of aromatic polyamide fibers, once the short fibers are disturbed, it becomes extremely difficult to align them, making it practically impossible to form them into yarn.

Usually, an oil agent of about 0.3 to 0.7% by weight based on the weight of the fiber, and in special cases about 1.0% by weight, is applied to the fiber in order to impart smoothness, cohesiveness, and other surface properties to the fiber. However, in the method of the present invention, it is impossible to smoothly produce a spun yarn-like yarn by applying an oil agent of such a commonly used concentration. In the present invention, the amount of oil attached is in the range of 0.05 to 0.30% by weight based on the weight of the fiber,
And the moisture content must be 7.0% by weight or less. If the amount of oil attached is less than 0.05% by weight, the fibers will repel each other due to the electric charge on the fibers, resulting in so-called disintegration, or the fibers will cling to the metal surface of the supply roller or tension cutting roller, resulting in uniform tearing. It becomes difficult. If the amount of oil attached exceeds 0.30% by weight, the oil will have a strong fiber focusing effect, making uniform tearing difficult. In extreme cases, tearing does not occur and severe dynamic friction occurs between the metal surface of the tension cutting roller and the fiber threads, causing the oil to burn and emit a strange odor. Moisture content must be less than 7.0% by weight. When the weight exceeds 7.0%, the same phenomenon as when the amount of oil attached exceeds 0.30% by weight occurs due to the fiber focusing effect due to moisture, and uniform tearing cannot be achieved.

To explain with specific examples, Fig. 1 shows an example of the process in the present invention, in which 1 is a polyparaphenylene terephthalamide fiber with an oil adhesion rate of 0.25% by weight and a water content of 4.0% by weight. 4400 denier tow. The distance between the fibers 1 is 750 mm.
The fleece was shredded 25 times between two sets of separated nip rollers 2 and 3, and the short fiber fleece with an average fiber length of 312 mm was produced by aligning the fibers while preventing the fiber arrangement from being disturbed. At this time, the short fiber fleece is passed through a funnel-shaped guide 4 and pulled downward to prevent expansion and diffusion of the short fiber threads. Furthermore, the short fiber fleece that has come out of the roller 3 is pulled out using an aspirator 5 that is in close contact with the roller 3 so as not to disturb the fiber arrangement, while the air swirling nozzle 6 is used to wind up the fibers present on the surface of the short fiber fleece. The fibers are bound in the longitudinal direction so that they do not come off, and wound into a winder 8 as a 30-count short fiber bound yarn. The conditions for the aspirator and the air swirl nozzle vary depending on the physical properties of the aromatic polyamide fibers, but for example, in this example, the air pressure of the aspirator is 3 kg/cm ² and the air pressure of the air swirl nozzle is 5 kg/cm ² .

In this case, when the tow of aromatic polyamide fiber is cut with a commonly used shortening means, that is, a tow cutter, and the fiber arrangement is disturbed into a fluffy state, the short fiber yarn is then beaten. Even when trying to arrange the fibers again by carding, drafting, etc., the rigidity peculiar to aromatic polyamide fibers becomes an obstacle, making it difficult to handle them like short fiber yarns obtained from synthetic fibers such as polyester fibers and nylon fibers. is not obtained, productivity is significantly reduced and it becomes impractical. However, as in the method of the present invention, a fiber bundle with an oil adhesion rate of 0.05 to 0.30% by weight based on the fiber weight and a water content of 7.0% by weight or less is cut into short fibers by a shredding method, and then the fibers are cut into short fibers. If the short fiber yarns are conjugated to form a yarn in such a way that they do not fall out in the longitudinal direction while preventing the arrangement from being disordered, the above-mentioned problems due to rigidity do not occur, and the resulting product is surprisingly A texture similar to that of conventional spun yarn can be obtained.

In this case, as a method for shortening the fibers, it is necessary to tear the fibers straight in the longitudinal direction (pulling direction) in order to prevent the fiber arrangement from being disturbed. By this method, it is possible to obtain a short fiber yarn in which the fiber arrangement in the longitudinal direction is well maintained. It is further desirable to add measures such as covering the short fibers with a guide that does not disturb the arrangement of the short fiber threads as much as possible when tearing them. Furthermore, it is desirable that the torn short fiber bundles be conjugated before their arrangement is disturbed. You can draft between them if necessary. However, even in that case, conditions must be set so that the fiber arrangement is not disturbed.

In addition, the oriented short fiber bundles that have reached the desired fineness in this arranged state are bound in the longitudinal direction so that they do not fall out, but as for this binding method, as in the above example, immediately after being made into short fibers, A method in which the fibers present on the surface of the short fiber bundle are wound around the short fiber bundle in places and conjugated thereto is efficient and fast, and is suitable for this method. Depending on the field of application, methods such as winding the fibers into short fiber bundles by actual twisting and binding them in the longitudinal direction may be used.

Further, as the aromatic polyamide fiber applicable to the present invention, the above-mentioned polyparaphenylene terephthalamide fiber as well as polymetaphenylene isophthalamide fibers The method of the present invention can be applied to aromatic polyamide fibers such as.

In this way, according to the method of the present invention, it is possible to produce a woven or knitted fabric featuring a texture similar to spun yarn using an extremely simple method using aromatic polyamide fibers, which has been difficult in the past. It has great application value in industrial applications such as bag filters and sports clothing.

[Brief explanation of drawings]

FIG. 1 is a process front view showing one embodiment of the method of the present invention.

Claims (1)

[Claims] 1. When manufacturing yarn from aromatic polyamide fibers, the fibers, which have an oil adhesion rate of 0.05 to 0.30% by weight based on the weight of the fibers and a moisture content of 7.0% by weight or less, are cut into short fibers using a shredding method. When converting to
A spun yarn-like yarn characterized in that it is drawn downward through a funnel-shaped guide, then suctioned with an aspirator, and then treated with an air nozzle to join the short fiber yarns in the longitudinal direction to form a yarn. Production method.