JPS6315378B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for simultaneously stretching and false twisting a polyester multifilament. In the above-mentioned stretch and false twist processing method of the present invention, it is an object of the present invention to provide a good textured yarn that has high crimping, little generation of fuzz, and exhibits an excellent texture when made into a fabric. In recent years, the production volume of bulky polyester yarn has increased.
This is increasing, and the proportion of false twisted yarn has reached 90%. In addition, there has been remarkable progress in improving the efficiency and performance of false twisting. In addition, methods for supplying yarn with a high degree of orientation have been proposed. On the other hand, the construction of the drawing and simultaneous false twisting device for carrying out this method is to use one in which a heating heater, a cooling plate, and a twisting device are arranged in this order between the supply roller and the drawing roller, and the undrawn yarn is After drawing and twisting the yarn while sufficiently heating it, the yarn is sufficiently cooled and untwisted to obtain a false twisted yarn. However, in the conventional stretching and simultaneous false-twisting method, when applying the heating necessary for stretching using a heating heater, as the processing speed increases, the heating time becomes shorter, making it impossible to perform the necessary and sufficient heating.
In order to make up for this lack of heat, the heating heater has been made longer, but if it is made too long, the height of the false twisting machine becomes high, which not only makes it impossible to thread the yarn, but also makes it difficult to manufacture the heater. However, there is a limit to the length of the heating heater, and the maximum length of the heating heater of the simultaneous stretching and false-twisting machine currently available on the market is at most
The maximum height is 2.5m. In this way, the conventional stretching and simultaneous false-twisting machine cannot provide a sufficient heater length during high-speed processing, resulting in insufficient crimp performance of the resulting false-twisted yarn, especially in the case of large fineness. , its shortcomings become noticeable. As a result, the final product, woven fabric, lacks volume due to low crimp performance.
It ends up having a paper-like texture. Another way to compensate for the lack of heating is to raise the heater temperature, but if the heater temperature is high, fuzz will increase during twisting.
Alternatively, an increase in thread breakage may cause operational problems. As mentioned above, in the simultaneous stretching and false twisting method, disadvantages become apparent as the crimping performance increases as the speed increases, resulting in a decrease in the feel of the finished fabric and an increase in the occurrence of fuzz. As a result of intensive studies to eliminate the above-mentioned drawbacks, the present inventors discovered that a processed yarn with excellent crimp performance could be obtained by controlling the temperature of the yarn entering the twisting device within a specific range. Ivy. After further investigation based on this knowledge, we found that by installing a second heating heater between the heating heater and the twisting device to reheat the yarn, it is possible to enter the twisting device even during high-speed processing. The present invention was achieved by discovering that yarn temperature can be controlled and processed yarn with excellent crimp performance can be obtained at high speed. That is, in the present invention, the thermal stress relaxation starting temperature is T _B
(°C) When simultaneously stretching and simultaneously false-twisting polyester-based undrawn yarn, first and second heating heaters and twisting devices are sequentially provided between the supply roller and the stretching roller, and at this time, the second heating heater The yarn temperature T ₁ (°C) at the entrance of the twisting device and the yarn temperature T ₂ (°C) at the entrance of the twisting device are maintained within the ranges of (1) and (2) below, respectively, while drawing and false twisting are performed at the same time. It is. T _B +70≦T ₁ ≦T _B +110 (1) T _B ≦T ₂ ≦T _B +60 (2) The present invention will be described in detail below with reference to the accompanying drawings. Figure 1 shows general thermal stress curves for undrawn polyester yarn, where curve A is for an undrawn yarn at a spinning speed of 3300 m/min, and curve B is for an undrawn yarn at a spinning speed of 1600 m/min. . As the heating temperature increases, the latent internal stress is relaxed, and the initial stress uniformly decreases to around 70°C. After that, when heated to 70°C or higher, stress suddenly develops and increases. When the temperature reaches around 90°C, stress relaxation occurs and the stress decreases. In the present invention, the temperature at which this thermal stress relaxation starts is hereinafter referred to as T _B (°C). Here, the thermal stress (peak stress) at the starting point of thermal stress relaxation changes depending on the spinning speed and yarn fineness of the undrawn yarn;
T _B itself is almost constant without being affected by spinning speed and yarn fineness. FIG. 2 is a schematic diagram showing one example of an embodiment of the present invention. In FIG. 2, a polyester undrawn yarn 1, which is a supplied yarn, is supplied at a constant speed by a supply roller 2, and is given a false twist by a twisting device 5. Sufficient heat is applied to the stretch-twisting mold in step 3 (heated). The yarn leaving the first heating heater 3 is naturally cooled down to T ₁ °C during its travel, but
The yarn is reheated by the heating heater 4.
The yarn leaving this second heater 4 is cooled to T ₂ and enters the twisting device 5 where it is twisted and untwisted. The yarn leaving the twisting device passes through a drawing roller 6, is heat-treated as needed by a secondary heat correction device (not shown) called a "second heater," and then passes through a delivery roller 7. After being oiled by an oiling roller 8, it is wound up into a package 9 via a winding device. By the way, in the drawing and simultaneous false twisting method as shown in FIG. 2, in order to obtain processed yarn with excellent crimp performance, the yarn temperature T ₂ entering the twisting device 5 must be within a specific range. is necessary. As a means of this, a new second
By installing a heating heater 4 and reheating it, it is possible to control T ₂ even during high-speed processing. The thermal history received during the period up to 5 is also important. That is, in order to obtain a processed yarn with excellent crimp performance at high speed, as in the present invention, the yarn that has left the first heating heater 3 and is at a specific temperature is reheated to perform twisting. The aim is to control the yarn temperature entering the device 5 within a specific range. Although the theoretical basis for improving crimp performance by reheating a yarn that has been cooled to a specific temperature is not yet clear, it is possible to It is thought that the heat setting effect is further improved due to the rearrangement of the elements. Hereinafter, the T ₁ temperature and T ₂ temperature mentioned above will be explained in detail. What is important in the present invention is that the yarn temperature T ₁ (°C) of the yarn heated, drawn and twisted by the first heating heater 3 as described above is T _B +70≦T ₁ ≦T _B +
The second heating element must be used to reheat the liquid after it has been cooled to a temperature in the range of 110°C. Note that T _B is the temperature at which thermal stress relaxation begins, as shown in FIG. This reheating makes it possible to improve the crimp performance, but if the reheating is performed after T ₁ becomes less than T _B +70°C, the crimp performance will not improve. or,
Even if T ₁ exceeds T _B +110°C, the crimp performance improvement effect cannot be obtained. Next, the yarn reheated by the second heater has a yarn temperature T ₂ at the entrance of the twisting section such that T _B ≦T ₂ ≦T _B +60
must be within the range. If T ₂ is lower than T _B , the crimp performance will deteriorate, and the texture of the resulting final product fabric will lack volume and become paper-like. Furthermore, if T ₂ is higher than T _B +60°C, the yarn temperature at the twisting portion is high, and fuzz will occur frequently. The preferable range of T ₂ is T _B +10≦T ₂
≦T _B +50. In addition, although a circumscribed twisting device is shown in Fig. 2, a spinner,
It goes without saying that inscribed friction, belt friction, etc. may also be used. The polyester yarn referred to in the present invention is a polyester filament containing 80 mol% or more of ethylene terephthalate units, and some of the acid components include phthalic acid, isophthalic acid, adipic acid, oxalic acid,
Dibasic acids such as sepacic acid, suberic acid, glutaric acid, pimelic acid, fumaric acid, and succinic acid may be substituted. Further, a polymerization degree regulator such as acetic acid or propionic acid may be included. On the other hand, a part of ethylene glycol may also be replaced by other alcohol components, such as polymethylene glycol having 2 to 10 carbon atoms, such as trimethylene glycol, butylene glycol, etc., or dihydric alcohol such as cyclohexanedimethanol. Furthermore, as a modifier, 5
-Oxydimethylisophthalate, 5-oxydimethylhexahydroisophthalate, benzene-
1,3,5-tricarboxylic acid, diethylene glycol, paracarbomethoxyphenyldiethylphosphonate, 3,5-dicarboxyphenyldiethylsulfonate, pentaerythritol, glycerol, glucose, phosphoric acid, triphenylphosphate, tri-1-carbomethoxy It may also contain a small amount of phenyl phosphate, triphenyl phosphonate, triphenyl aruzenite, triphenyl porate, sorbitan, trimesic acid, etc. In other embodiments, polyamides such as polycarbonate, nylon-6, or nylon-66,
It may also contain small amounts of other polymers such as polyurethane and polyolefin. The cross-sectional shapes of the undrawn polyester yarns that can be used in the present invention include normal circular cross-sections, irregular cross-sections (triangular, pentagonal, hexagonal, octagonal, flattened, cross-shaped, etc.), and hollow cross-sections (doughnut-shaped, irregularly shaped hollow). It may be any of the following. As described above, according to the present invention, disadvantages such as deterioration of crimp performance and generation of fuzz in high-speed simultaneous stretching and false-twisting processing, which could not be avoided with conventional methods, are eliminated, and high-speed processing can be achieved. It has the extremely excellent advantage of improved properties. In addition, T _B , TC, fluff,
The method for measuring yarn temperature will be explained below. (a) Thermal stress relaxation start temperature T _B (°C) A thermal stress meter manufactured by Kanebo Engineering Co., Ltd. was used, and the measurement conditions were a temperature increase rate of 2.5°C/sec and an initial load of 5 mg/d. (b) Crimp performance [TC (%)] Measured according to the method described in British Patent No. 1333679. The larger this value is, the better the crimp performance is. (c) Fuzz This value was measured for 5 minutes using a L-DT104-01 fuzz counting device manufactured by Toray Industries, Inc. while running at a yarn speed of 400 m/min and a tension of 0.1 g/d, and the measured value was the average value of 5 times. . (d) Yarn temperature This is the value measured using a yarn thermometer manufactured by TRANS-MET ENGINEERING. The measurement point shall be within 5 cm from the first heater inlet or the twisting device inlet.
Hereinafter, the present invention will be explained in more detail with reference to Examples. Example Polyethylene terephthalate having an intrinsic viscosity of 0.65 was spun at a spinning speed of 3300 m/min. The thermal stress relaxation onset temperature T _B of the obtained 225 denier undrawn yarn was 90°C. This undrawn yarn was subjected to stretching and simultaneous false-twisting using the drawing and simultaneous false-twisting apparatus shown in FIG. 2, changing the installation position of the second heating heater and the heater temperature under the following conditions. Processing speed: 800 m/min, stretching ratio: 1.51, twisting device: ceramic disc (triaxial), first heating heater length: 2.5 m, second heating heater length: 1.5 m Crimping of the obtained false twisted yarn The performance, fabric texture, and fuzz are also shown in the table below. The results obtained by the conventional processing method without using the second heater are also shown in the following table.

[Table] In the table, No. 25 is processed using the conventional processing method that does not use a second heating heater, and the T ₂ temperature is 51
℃, the crimp performance (TC) of the resulting processed yarn was poor, and the texture of the fabric was also poor. Compared to this conventional method, No. 3, 4, 8, 9, 10,
14, 15, 16, and 20 are examples of the method of the present invention, and the processed yarns obtained have extremely little fluff, good crimp performance (TC), and the texture of the final product is satisfactory. It was hot. On the other hand, No. 5, 6, and 11 are examples in which the T ₁ temperature is lower than the range of the present invention, and No. 7,
Nos. 13 and 19 are examples in which the T ₁ temperature is higher than the range of the present invention, but both are examples in which the T ₂ temperature is within the range of the present invention. By reheating the yarn at T ₁ temperature, which is outside the range of the present invention,
Even if the T ₂ temperature was controlled to be within the range of the present invention, the crimp performance (TC) of the resulting processed yarn was insufficient and the texture of the fabric was also unsatisfactory. Further, No. 2 is an example in which the T ₁ temperature is within the range of the present invention, but the T ₂ temperature is lower than the range of the present invention. In this case as well, the crimp performance (TC) of the processed yarn obtained was insufficient, and the texture of the fabric was also unsatisfactory. On the other hand, No. 22 is an example in which only the T ₂ temperature is higher than the range of the present invention, and although the obtained processed yarn had a satisfactory crimp performance (TC), it had a lot of fuzz.

[Brief explanation of the drawing]

FIG. 1 is a graph illustrating a thermal stress curve of an undrawn polyester yarn used in the method of the present invention, and FIG. 2 is a schematic diagram showing an example of an embodiment of the present invention.

Claims (1)

[Claims] 1. When stretching and simultaneously false-twisting a polyester-based undrawn yarn whose thermal stress relaxation starting temperature is T _B (°C), first and second A heating heater and a twisting device were installed one after another.
At that time, the yarn temperature at the inlet of the second heating heater
T ₁ (°C) and yarn temperature T ₂ at the twisting device inlet
A high-speed false-twisting method characterized by carrying out simultaneous stretching and false-twisting while maintaining (°C) within the ranges of (1) and (2) below, respectively. T _B +70≦T ₁ ≦T _B +110 …(1) T _B ≦T ₂ ≦T _B +60 …(2)