JPS6354813B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to improvements in multifilament yarns made of polyester fibers.

[Prior art] When weaving multifilament yarns, it is customary to apply a sizing agent to the warp yarns to prevent fluffing in order to improve weaving performance, but as this increases the cost, recently it has become a practice to entangle the multifilament yarns. It is also practiced to prevent fuzzing and omit gluing. However, this method has no particular problem with relatively flexible fibers such as nylon, but with rigid fibers with high modulus such as polyester, ridges of single fibers occur when yarns are entangled, and the It also has less elasticity than other fibers, so when it is rubbed strongly, it generates fuzz, which gets entangled with neighboring threads and causes poor opening during weaving. This tendency is particularly noticeable as the number of filaments increases.

[Object of the Invention] An object of the present invention is to provide a polyester multifilament yarn with good sizing-free weavability and less fuzzing even when rubbed.

[Structure of the Invention] (1) According to the present invention, a multifilament yarn obtained by spinning a fiber-forming polymer having ethylene terephthalate as a main repeating unit, which has an overall degree of entanglement of 15 or more per m. A polyester multifilament yarn characterized in that the number of partial protrusions due to free single fibers on the yarn surface is 2 or less per meter, and the yarn as a whole does not substantially contain unstretched portions, and (2) The birefringence △n obtained by spinning a fiber-forming polymer containing ethylene terephthalate as a main repeating unit and then semi-stretching or high-speed spinning
Partially drawn multifilament yarn of 0.02 or more is subjected to air turbulence treatment to give inter-fiber entanglement of 35 or more per meter, and then drawn at a magnification of 1.2 to 2.0 to form a single fiber containing virtually no undrawn parts. The raised area is m
A method for producing a polyester multifilament yarn is provided, which is characterized in that two or less intertwined yarns are formed per yarn.

[Operation, principle] Figure 1 is a side photograph of a conventional polyester filament yarn for glueless weaving, in which the single fibers were entangled by the conventional method by air treatment after spinning and drawing. . When weaving these products without twisting or glue, the loom sometimes stops, but when we investigate the cause of this, it is often found that fuzz has occurred in the threads. Therefore, when we further clarified the cause, we found that the partially raised areas due to free single fibers existing on the yarn surface, as shown by the arrows in the figure, are easily broken due to the friction of the heddles during weaving, resulting in fuzz. It turned out that I was getting used to it. Here, A and B in the figure are 50De/36fil and 50De/24fil, respectively.
In this example, it has become clear that as the number of filaments increases, the locally raised portions become more protruding, and the denier of the single fibers also becomes thinner, making them more susceptible to abrasion, breakage, and fuzzing. On the other hand, FIG.
36 Despite having a large number of filaments, it has an intertwined structure with few locally raised parts due to free single fibers, so there is little fluffing even when rubbed, and there are very few stops during weaving. Of course, such protrusions can be reduced by simply lowering the degree of entanglement, but this will also reduce the degree of bonding between single fibers, causing yarn breakage and reducing weavability, so it is not effective. . Therefore, the degree of confounding that satisfies the degree of connectivity, that is, the degree of confounding at least
An important point of the yarn of the present invention is to keep the number of partial protrusions due to free single fibers to 2 or less per meter while keeping the yarn at 15 or more, preferably 25 or more.

In addition, there are various ways to make such threads, such as a method in which the fibers are sufficiently opened using electricity etc. and then intertwined, or a method in which the fibers are entangled at low speed in water, but the most effective method is to use threads. By pre-intertwining the threads in a semi-stretched state as shown in Figure 2B, and then drawing them, the protruding free fibers can be pulled into the yarn by drawing while leaving the intertwined structure as a whole, thus satisfying the above conditions. It is preferable to use a method of smoothing the surface of the thread so that the surface of the thread is smooth, and the thread shown in FIG. 3A was made using this method.

In this case, if the normally spun undrawn yarn is simply intertwined, the occurrence of drawing necks will change in the intertwined portions, and the undrawn portions will be mixed in spots in the drawn yarn, resulting in significant damage to the product. Lower it. To prevent this, it is necessary to at least reduce the birefringence of the yarn to be entangled.
By increasing the orientation to 0.02 or higher, avoiding neck stretching by not increasing the stretching ratio higher than 2.0 times, and stretching in a flow manner, even if entanglement occurs, unstretched portions will not be mixed. In order to obtain such high orientation, it is preferable to half-draw the undrawn yarn or to spin it at high speed to make a partially drawn yarn. By doing this, no unstretched portion remains, so it is no problem even if strong entanglement is applied before stretching, and as a result, large entanglements can be left after stretching. Therefore, it is desirable that the number of entanglements before stretching be 35 or more, more preferably 50 or more per m.

On the other hand, if the stretching ratio after entanglement is too low, the raised parts of the free single fibers will not be fully stretched.
This stretching must be at least 1.2 times. In addition, hot stretching is preferable in order to maintain the shape of the raised portions stretched by stretching without returning to their original shape after stretching, and to promote flow stretching.

Furthermore, as mentioned above, the more the multi-filament is used, the more free raised fibers there are, so the effect of the present invention becomes even more effective as the number of filaments increases, especially when the number of multi-filaments becomes 24 or more. It's finally becoming noticeable. Furthermore, if the number of fibers exceeds 36, high-speed weaving without twisting or gluing is almost impossible unless the present invention is used.

Further, as a guideline for imparting such an effect, it is desirable that the number of fuzz generated when the yarn is bent and rubbed in the right angle direction with a tension of 0.4 g/d is 0.2 or less per m. As the bending member, it is preferable to use a sapphire edge used as the fulcrum of the balance. It is convenient to use a commercially available fuzz counter to measure the number of fuzz generation.

In the present invention, the polyester includes, in addition to regular polyethylene terephthalate, a so-called third component, such as a copolymer of isophthalic acid, an ionic dyeable metal salt, etc., or a blend of an antistatic polymer, etc. It is well adapted. Alternatively, even mixed fiber yarns with different deniers, foreign properties, and different polymers can be applied as long as the yarn form is satisfactory. Alternatively, it may be applied to a conduit gate, etc., as long as the yarn form is satisfied.

Example 1 Polyethylene terephthalate was melt-spun at 1100 m/min to obtain an undrawn yarn of 154De/36fil. The birefringence Δn at this time was 0.008. Next, heat it to 200℃ while preheating it with a hot roller at 100℃.
Stretched at 2.2 times on a plate with birefringence △n=
0.047 semi-drawn yarn, and then compressed air pressure 4
The yarn was subjected to air turbulence treatment at Kg/cm ² to give 95 entanglements per meter, and then stretched 1.4 times using a plate at 180° C. to obtain a 50 De/36 fil yarn with an entanglement degree of 41.
When this thread was magnified 100 times with a binocular stereomicroscope to observe partial raised areas due to free fibers, there were almost no raised parts. When this yarn was briefly knitted and dyed with a dye for spot testing, no unstretched areas were observed. Furthermore, when this was rubbed at right angles with a saphire edge used as a balance under a tension of 0.4 g/d, the number of fuzz generated was 0.1 per m. Next, this yarn was fed to the water jet room as a warp without twisting and without glue, and a 2500t/m twisted polyester 75De/36fil ordinary yarn was used as a weft to weave a pallet, but the loom did not have many stops. It showed good weavability.

Comparative Example 1 In Example 1, the spun undrawn yarn was completely stretched at a draw ratio of 3.1 times and then subjected to the same compressed air turbulence treatment to give 67 entanglements per m. When this yarn was similarly observed under a microscope, partial protuberances of free fibers at intertwining points were noticeable, and when counted, the number was found to be 5.6 per m on average. Similarly, the number of fluffs generated was 0.6 per m. When I wove a palace in the same way, the loom stalled a lot.
It had no practical use at all.

Comparative Example 2 The undrawn yarn spun in Example 1 was stretched by 2.8 times, subjected to compressed air turbulence treatment in the same manner, and then similarly stretched to 1.1 times on a plate at 180°C. I tried to reduce the partial protrusion, but it had almost no effect.

Comparative Example 3 The undrawn yarn spun in Example 1 was directly subjected to pressure air turbulence treatment, and then stretched at a factor of 3.1 to obtain a yarn with an entanglement degree of 32. When this was similarly dyed with a stain test dye, very fine dark spots due to unstretching appeared on the entire surface, making it unusable. In addition, in order to suppress this unstretched occurrence,
When the air pressure in the turbulent flow treatment was lowered to 1 kg/cm ² , undrawn spots in the resulting yarn decreased, but at the same time, the degree of entanglement of the yarn also decreased to 7.8 per meter, causing yarn cracking during weaving and causing twisting or twisting. It was impossible to weave without gluing.

Example 2 Polyethylene terephthalate was melt-spun at 3300 m/min to produce 80De/48fil with birefringence △n=0.035.
A partially drawn yarn was obtained. Next, this was treated with turbulence using compressed air at 3 kg/cm ² to give 67 entanglements per meter, and then 80
Stretched at 1.6 times through a slit heater at 210℃ while preheating with a hot roller at ℃, and the degree of entanglement was 28.
A 50De/48fil drawn yarn was obtained. Observation of the yarn revealed that there were almost no localized protrusions on the yarn, and if there were any, the number was less than one per m, and no staining spots were observed in the staining test. Next, we used this untwisted and uns glued cloth as a weft to weave taffeta in a water jet loom, but the weavability was better than that of the conventional method.
Compared to 50De/20fil interlaced yarn, 50De/48fil had a larger number of filaments, but the number of loom stops was not much different and was at a practical level.

[Brief explanation of drawings]

Figure 1 is a micrograph of the side of a yarn (60x magnification) showing the shape of a conventional interlaced yarn, and Figure 2A is a microscope photo of the side of a yarn (60x magnification) showing the shape of the entangled yarn of the present invention.
Fig. 2(b) is a micrograph (magnification: 60x) of the side surface of the yarn before obtaining the interlaced yarn of the present invention.

Claims (1)

[Scope of Claims] 1. A multifilament yarn obtained by spinning a fiber-forming polymer containing ethylene terephthalate as a main repeating unit, despite having an overall degree of entanglement of 15 or more per m. A polyester multifilament yarn characterized in that the number of partial protrusions due to free single fibers on the surface of the yarn is 2 or less per m, and the yarn as a whole does not substantially contain unstretched portions. 2. The yarn according to claim 1, wherein the multifilament yarn comprises 24 filaments or more. 3. The yarn according to claim 1, which has a fuzz generation rate of 0.2 fibers per m or less when the yarn is bent at right angles and rubbed under a tension of 0.4 g/d. 4 A partially drawn multifilament yarn with a birefringence △n of 0.02 or more obtained by spinning a fiber-forming polymer containing ethylene terephthalate as a main repeating unit and further semi-drawing or high-speed spinning is subjected to air turbulence treatment. After giving 35 or more inter-fiber entanglements per meter, this is stretched by a factor of 1.2 to 2.0 to form an entangled yarn with substantially no unstretched portions and no more than 2 single fiber protrusions per meter. A method for producing polyester multifilament yarn, which is characterized by: