JPS636655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a torque yarn particularly useful for stockings, and more particularly to a torque yarn consisting essentially of poly(tetramethylene) terephthalate. Conventionally, 10 to 50 denier polyamide false twisted crimped yarn and polyamide conjugate yarn have been used as materials for stockings, but when these crimped yarns are used, the transparency of the stockings is lost and the appearance is poor. Become something. In recent years, stockings have become established as a fashion product, and there is a growing demand for stockings with particularly good transparency and a good texture, and torque yarn is attracting attention as a processed yarn that satisfies these demands. This "torque yarn" is a woolly-like processed yarn in which the number of false twists is added to the highest possible range in the false twisting process, whereas For example, it is a torque-textured yarn that has latent torque but does not have substantial crimp, as shown in Japanese Patent Application Laid-Open No. 1344/1983. Such torque yarns have conventionally been composed of nylon 6 or nylon 66, but while stockings using such polyamide torque yarns have excellent transparency, they have poor elasticity and are also susceptible to irregularities in the stitch loops called "katsupa". Knitting spots occur. The transparency of stockings is mainly based on the convergence of the yarn, the relative relationship between the stitch loop and the crimp waveform of the yarn, the elasticity is mainly based on the torque force of the yarn, and the "katsupa" is based on the longitudinal direction of the yarn. Generally speaking, the higher the torque during knitting and the larger the stitch loop, the more likely it is that "katsupa" will occur. Since stockings using torque yarn place emphasis on elegance, the occurrence of such "katsupa" spoils the aesthetic appearance of the stockings and is a fatal defect as a product. Also, if the torque during knitting is high, over-unraveling (snarling) may occur.
It also causes deterioration in knitting operability due to such factors, and has a negative impact on productivity. From this point of view, it is desirable for torque yarns for stockings to have as low a torque as possible during knitting and to have a high torque after production. By the way, as a method for preventing the occurrence of "clips" in stockings using torque yarn, it is known to apply additional twist to polyamide torque yarn, as disclosed in, for example, Japanese Patent Application Laid-Open No. 52-88645. However, additional twisting not only complicates the manufacturing process but is also extremely disadvantageous in terms of cost. In addition, it has recently been proposed to prevent the occurrence of "katsupa" by selecting the crimp recovery rate, torque index, elongation at break, and balance between the number of filaments and denier of polyamide false twisted yarn. (Refer to Japanese Patent Application Laid-Open No. 55-26221). However, adjusting all these values within specific ranges requires extremely delicate and strict control in terms of quality and process control. The inventor of the present invention has conducted extensive research in order to solve the above-mentioned drawbacks of polyamide torque yarn and to provide a new torque yarn that satisfies all requirements for stockings. The inventors have discovered that a yarn having a specific torque characteristic is extremely preferable for stockings without the drawbacks of conventional torque yarns, and has thus arrived at the present invention. That is, the present invention provides at least 95 (by weight) of the yarn.
% of poly(tetramethylene) terephthalate, the yarn is a torque yarn having substantially no crimps, and the yarn has (1) a torque index (T/m) in boiling water (96-98°C); )
is 400/√(T/m) to 800/√(T/m), (2) Torque potential rate is 55% to 65%, (3) Torque retention rate is 20% to 30%. (4) Preferably, the total denier (De) is 7 to 20 and the number of constituent filaments is 1 to 3. This torque yarn is suitable for stockings. The torque yarn of the present invention as described above has an extremely low torque index in air and is latent.
It has good knitting properties, less occurrence of "katsupa", has a much higher torque index in boiling water than conventional nylon 6 torque yarns and nylon 66 torque yarns, and has good elasticity. The "torque index in air" mentioned here refers to a product that has been left for more than two weeks after processing at 20±2℃ and 65±5℃.
% atmosphere for 24 hours, the thread taken out from the bobbin was made into a loop, a load of 0.1 g/de was applied to the other end, and the thread was left in the air until it came to rest. The number is calculated per meter, and is mainly useful as a substitute for knitting properties and "katsupa". In addition, "torque index in boiling water" refers to products that have been left for more than two weeks after processing.
After leaving the thread in an atmosphere of 20±2℃ and 65±5% for 24 hours, take the thread out of the bobbin and tie it into a loop.
The number of twists per meter is calculated by leaving the ring in boiling water (96-98℃) under a load of 0.1g/de until it comes to rest, and then folding it into two.It is mainly used as a substitute for elasticity. Useful. In addition, "torque latent rate" means the rate of latent torque index in air, and is expressed by the following formula: Torque latent rate = torque index in air immediately after machining - air on the 20th day after machining Defined as torque index in air/torque index in air immediately after machining x 100(%). This value is 35-45% for the nylon 6 torque yarn, but 50% for the poly(tetramethylene) terephthalate torque yarn of the present invention.
reaching ~65%. The "torque index in boiling water" of poly(tetramethylene) terephthalate torque yarn is more than three times that of nylon 6 torque yarn, and the "torque retention rate" defined by the following formula is nylon 6 torque yarn.
It is in the range of 5-15% for torque yarns, whereas it is 20-30% for the poly(tetramethylene) terephthalate torque yarns of the present invention. Torque retention rate = Torque index in boiling water / Torque index in air immediately after processing x 100 (%) The characteristics of such poly(tetramethylene) terephthalate torque yarn are explained in comparison with nylon 6 torque yarn. do. Figure 1 shows an example of the change in the "torque index in air" over time, where a torque yarn made of poly(tetramethylene) terephthalate (indicated by line A) is compared to a torque yarn made of nylon 6 (indicated by line B). This shows that the latent rate of ``torque index in air'' is larger than that of ``torque index in air''. Figure 2 shows an example of the ``torque index in water at each temperature'', and the torque index of poly(tetramethylene) terephthalate decreases unilaterally from 20℃, whereas the torque index of nylon 6 (indicated by line B) decreases unilaterally from 20℃. The torque yarn (indicated by line A) made of Nylon 6 reaches its maximum at 55-60°C, indicating that the "torque index in boiling water" is higher than that of nylon 6. The torque yarn of the present invention as described above has 95
(% by weight) or more, preferably substantially 100%, of poly(tetramethylene) terephthalate, as well as having a torque index (T/m) in boiling water of 400 depending on the yarn denier (De) of the torque yarn. /
It is necessary that the torque potential is within the range of √~800/√(T/m), the torque potential rate is 50%~65%, and the torque retention rate is within the range of 20~30%, and each of these A fabric whose crimp characteristics satisfy all of the above conditions has good knitting properties, has no "clips" in the knitted fabric, has an excellent stitch surface, and has excellent functionality as stockings. The torque yarn preferably has a total denier of 7 to 20 de and has 1 to 3 filaments.
In other words, if the total denier exceeds 20 de, the sheerness of the knitted fabric tends to be poor and the texture becomes stiff, and if the total denier is less than 7 de, thread breakage is likely to occur during spinning, false twisting, weaving, etc. The durability of the knitted fabric also decreases. Further, if the number of filaments exceeds 3, the convergence is poor and the sheerness is reduced. Such a torque yarn of the present invention is produced by heating drawn poly(tetramethylene) terephthalate yarn with an intrinsic viscosity [η] of 0.68 to 0.82 at a heater temperature of about 160 to 190°C for a short time, while twisting the yarn at a twist angle θ of 6 to 17 degrees. It can be manufactured by false twisting so that it becomes. The number of twists T and the twist angle θ are calculated using the following formula: (However, De is the yarn denier, and ρ is the yarn density, which is 1.33 for yarn made of poly(tetramethylene) terephthalate homopolymer.) Within the range where θ is 6 to 17 degrees, The number of twists may be selected appropriately. This false twisting process can be performed continuously following the stretching, or can be performed in a separate step after the stretching.
Further, as the false twisting means, it is preferable to use an internal or external friction false twisting means, but it is also possible to use a conventional spindle. The torque yarn according to the present invention is fully satisfactory in terms of knitting and processability in the stocking manufacturing process, and the stocking products have good transparency and stretchability, are free from stitch irregularities called "katsupa", and are also resistant to wind. It also has a very good fit (touch). Next, examples of the present invention will be described in detail. These examples will help better understand the effects of the torque yarn according to the invention. Example 1 Two-filament drawn poly(tetramethylene) terephthalate yarns of various deniers were
Using a woolly processing machine, processing speed 100m/min,
False twisting was performed under the conditions of a heater temperature of 175°C and a twisting angle (θ) of 10°. The obtained poly(tetramethylene) terephthalate processed yarn is knitted into stockings using a KT412V (Nagata Seiki) knitting machine, and after scouring, dyeing, and softening treatment, it is placed in a high-pressure steam setter.
The foot print was set at 115°C for 30 seconds. Table 1 shows the physical properties of the poly(tetramethylene) terephthalate torque yarn and the evaluation results of the stockings prepared. (In addition, the stocking evaluation was carried out by a sensory test by an expert.
Ranked as good...〇, average...△, and poor...×. )

[Table] (Note Nos. 2 to 6 are examples of the present invention, others are comparative examples)
As is clear from Table 1, the stocking properties made from the torque yarn of the present invention made of poly(tetramethylene) terephthalate are better than those of the torque yarn made of nylon 6 (knitability, transparency, cuff, texture, elasticity). Obviously in good condition. As a result of the comprehensive evaluation, a denier of 7 to 20 denier is good. Example 2 Two-filament poly(tetramethylene) terephthalate yarns were drawn and subsequently subjected to friction false twisting to produce various torque yarns. During stretch false twisting, processing temperature is 1000m/min, heater temperature
The conditions were 185°C and a twist angle (θ) of 10 degrees. The obtained processed yarn was knitted into stockings using a KT-412 knitting machine, and after being scoured, dyed, and softened, it was set in a high-pressure steam setter at 115°C for 30 seconds to make a foot shape. The results are shown in Table 2, and it is clear that the stockings satisfying the conditions of the present invention (Nos. 13 to 15) are good stockings.

【table】 [Brief explanation of the drawing]

Figure 1 is a graph showing the change in "torque index in air" over time for poly(tetramethylene) terephthalate torque yarn and nylon 6 torque yarn. This is a graph showing the "torque index in water at various temperatures" for torque yarns, and in FIGS. 1 and 2, line A represents a poly(tetramethylene) terephthalate torque yarn, and line B represents a nylon 6 torque yarn.

Claims (1)

[Scope of Claims] 1. A torque yarn in which at least 95% (by weight) of the yarn consists of poly(tetramethylene) terephthalate, the yarn being substantially non-crimped, the yarn comprising (1) boiling water (96 Torque index (T/m) at ~98℃)
is 400√(T/m) to 800√(T/m) (however, De is the total denier), (2) Torque potential rate is 55% to 65%, and (3) Torque retention rate is 20% to 30%. 2. Claim 1 in which the total denier (De) is 7 to 20 and the number of constituent filaments is 1 to 3.
Torque yarn as described in section. 3. The torque yarn according to claim 1 or 2, to which torque is imparted by false twisting.