JPH022976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing bulky polyester yarn having a silk-like texture, and more specifically to a method for producing undrawn yarn or low-drawn yarn made of polyester multifilament having a specific birefringence index. The present invention relates to a method for producing the bulky yarn, which involves false twisting while drawing. In addition to false-twisting machines with a single heat-setting zone, false-twisting machines with two heat-setting zones, a first and a second heat-setting zone, are used before and after the false-twisting spindle. A specific example of a false-twisting machine having a wide range of areas is the false-twisting machine described in Japanese Utility Model Publication No. 41-20590. Although the false-twisted yarn produced by this false-twisting device has a low torque, it is heat-set in the secondary heat-setting zone after untwisting, so it can be heated using a well-known Italian crimping machine or a single heat-setting device. Like yarn processed by a false twisting machine with a fixed area, it cannot eliminate the waxy feel characteristic of synthetic fibers, and is suitable as a forming material for knitting and woven fabrics that require a silk-like feel and supple drapability. was lacking. The inventors of the present invention have conducted extensive research in order to eliminate the above-mentioned drawbacks of conventional false-twisted yarns.
Undrawn or drawn yarn made of polyester multifilament having a specific birefringence index is false-twisted while being stretched, and the secondary heat setting is performed at the same time as untwisting to create a silk-like texture and fullness. The present invention was achieved by discovering the fact that it is possible to produce a bulky yarn suitable as a forming material for knitted and woven fabrics, which has both drapability and moderate shirring. Therefore, in the present invention, when undrawn yarn or low-drawn yarn made of polyester multifilament with a birefringence Δn of 0.008 to 0.120 is subjected to false twisting while being stretched, the stretching ratio DR specified by the following formula () is applied. The yarn is continuously introduced into a false twisting area, a primary heat setting area, and an _untwisting /secondary heat setting area while maintaining ℃ primary heat setting is performed, and the yarn heating temperature HT ₂ is 180℃ to 220℃ in the above untwisting/secondary heat setting area, and the above HT ₂ is
The gist _{of the present invention is a method for producing a kneaded silk-like bulky yarn in which secondary heat setting is performed at a temperature where the difference between HT 2 and} HT ₁ is 20° C. or higher, together with untwisting. Hereinafter, 0.51(1+ε)≦DR≦0.65(1+ε)() (where ε is the elongation at break of the undrawn yarn or the low-drawn yarn) The present invention will be described in detail below with reference to the accompanying drawings. In the drawings, FIG. 1 is an explanatory diagram of a false twisting process illustrating a first embodiment of the present invention, and FIG. 2 is an illustration of a second embodiment of the present invention using a false twisting machine having hot pins. It is a diagram. In Figure 1, the birefringence △n is 0.02 to 0.12
A low-drawn yarn A made of polyester multifilament is introduced into the false-twisting zone by a supply roller 1 through a yarn guide. A false twisting area is formed between the supply roller 1 and the false twisting spindle 5;
A first heat-setting heater 4 is arranged in the false twisting area along the running direction of the yarn. Further, a feed-out roller 2 is provided downstream of the false-twisting area, and a second heat-setting heater 6 is provided in the untwisting area between the feed-out roller 2 and the false-twisting spindle 5 along the running direction of the yarn. It is located. The polyester multifilament A introduced into the false twisting area is given false twist crimp while being stretched at a specific magnification defined by formula () using the speed difference between the supply roller 1 and the delivery roller 2. That is, the yarn A that has been false-twisted while being drawn by the false-twisting spindle 5 undergoes primary heat-setting by the first heat-setting heater 4, and then is introduced into the untwisting/secondary heat-setting area. and in that area under the action of untwisting tension and untwisting torque the second
After undergoing secondary heat fixation by the heat fixation heater 6,
Then, it is wound up as a bulky yarn 7 by a winding roller 3. FIG. 2 is an illustration of the method of the present invention using a false-twisting apparatus provided with a hot pin 15 and a twisting guide 9 in the false-twisting area. In this embodiment,
An undrawn yarn B made of polyester multifilament with a birefringence △n of 0.008 to 0.02 is introduced into a false twisting area by a supply roller 8 via a yarn guide; A hot pin 15, a twisting guide 9, and a first heat-setting heater 12 are provided in this order along the traveling path of the yarn toward the thread 14. For this reason, before introducing the undrawn yarn B into the primary heat-setting zone, the undrawn yarn B is first stretched under heating on the hot pin 15 while the twisting guide 9 restricts the twist run-up by the false twist spindle 14. be done. Therefore, the primary drawing is performed before the yarn B is introduced into the first heat-fixing heater 12, and the yarn B is then subjected to the speed difference between the yarns passing through the hot pin 15 and the delivery roller 10. During the secondary stretching to be used, the first heat setting heater 12 applies the first heat setting, and then the second heat setting heater 13 between the false twist spindle 14 and the feed roller 10 applies untwisting tension and unraveling. The bulky yarn 1 is processed by winding rollers 11 after undergoing a secondary heat setting process under the action of twisting torque.
It is rolled up as 6. In this embodiment, the product of the primary stretch ratio and the secondary stretch ratio corresponds to the stretch ratio DR defined by formula (). Two embodiments of the present invention have been described based on FIG. 1 and FIG. An essential component is that the drawn yarn be false-twisted while being drawn in accordance with a specific draw ratio DR defined by formula (). By satisfying this condition, it is possible to stably produce a silk-like bulky yarn that has low torque and has appropriate elastic recovery and Young's modulus. On the other hand, if the false-twisting processing conditions are outside the preferred range of the present invention, the effects unique to the present invention of generating untwisting torque and at the same time slowly relaxing stress in a relatively long yarn running section cannot be achieved. Therefore, the physical properties of the bulky yarn are impaired. For example, DR
When drawing conditions of <0.51 (1+ε) are adopted, the elongation of the obtained bulky yarn becomes excessive even if false twisting is performed at the same time as drawing, and untwisting occurs. On the other hand, when drawing conditions such as DR>0.65 (1+ε) are adopted, the waxy feel characteristic of synthetic fibers remains in the texture of the bulky yarn, making it impossible to achieve the object of the present invention. In carrying out the present invention, in order to improve the physical properties of the bulky yarn, the yarn heating temperatures HT ₁ and HT ₂ in the primary heat-setting region and the untwisting/secondary heat-setting region are 160°C≦HT ₁ ≦200°C and 180°C, respectively. ℃≦ _HT2 ≦220℃,
And it is set so as to satisfy the range of HT ₂ −HT ₁ ≧20°C. For example, if HT ₁ is set below 160℃, the dimensional stability of the product will be impaired in the post-processing process because the primary heat setting will not be sufficient.
When HT ₁ exceeds 200°C, the yarn becomes partially untwisted. Furthermore, when HT ₂ is less than 180°C, secondary heat fixation is insufficient, making it impossible to obtain a yarn with low torque, which results in skewing in the finished textile fabric. On the contrary, when HT ₂ exceeds 220°C, the heat setting effect due to secondary heat setting becomes excessive, the crimp form of the bulky yarn is impaired, and the bulkiness is reduced. Further, in the method of the present invention, it is desirable to determine the preferred range of the number of false twists (T/M) given to the yarn using the following formula (). That is, the number of false twists N (T/M) is preferably set according to the formula 1.32T≦N≦1.40T (). Here, T is Heberlein's formula, T=(275000/D+60)+
800, and D is the total denier of the resulting bulky yarn. When the number of false twists N given to the yarn is less than 1.32T, the twisted state is weak, the crimp becomes rough, and the expansion/contraction recovery rate decreases. Therefore, fabrics knitted and woven from this bulky yarn have insufficient bulk and morphological stability. On the other hand, if the number of false twists N exceeds 1.40T, a double twist phenomenon occurs due to excessive false twisting, and problems such as uneven weaving, uneven knitting, or yarn breakage occur frequently in subsequent processes. do. By satisfying the above-mentioned preferred conditions, the present invention makes it possible to produce a bulky yarn suitable as a fabric-forming material that has a silk-like bulge, supple drapability, as well as an appropriate amount of shear and elasticity. Hereinafter, preferred embodiments of the present invention will be described based on Examples. Example 1 A polyester multifilament (130・1d・36 filament) with a birefringence index △n of 0.0391 and a low draw yarn (ε=1.39) was supplied to the false twisting machine shown in FIG. 1 and subjected to the following conditions. False twisting was performed according to the method. Rotation speed of false twisting spindle 300000r.pm Stretching ratio DR 1.53 Number of false twists N Left twist 3630T/M Temperature in primary heat setting area 190℃ Temperature in secondary heat setting area 215℃ Results of measuring the physical properties of the obtained bulky yarn is shown below. Elasticity recovery rate: 12% (measured according to JIS L-1090) Torque: 14T/M (measured according to JIS L-1090) Young's modulus: 841Kg/cm ² (measured according to JIS L-1073) The total denier of the thread is 86d,
Fabrics woven with this as warp and weft have a silk-like surface effect and fullness without uneven weaving,
The drapability and the silkiness were also very good. Example 2 A low-drawn yarn (ε=1.02) made of polyester multifilament (105d/96 filament) with a birefringence index △n of 0.11 was supplied to the false twisting machine shown in Fig. 1, and was twisted according to the following conditions. False-twisted. Rotation speed of false twisting spindle 300000r.pm Stretching ratio DR 1.28 Number of false twists N Left twist 3680T/M Temperature in primary heat setting area 180°C Temperature in secondary heat setting area 210°C Obtained using the same method as in Example 1. The physical properties of the bulky yarn were measured. The measurement results are shown below. Stretching and recovery rate: 16% Torque: 12T/M Young's modulus: 904Kg/mm ^2The total denier of this bulky yarn is 85d,
This is used as warp and weft at a warp density of 119/
A woven fabric with a plain weave structure of 25.4 mm and a weft density of 90 threads/25.4 mm was manufactured. The resulting fabric had supple drape and fullness, and had a smooth feel similar to Fuji silk. Example 3 An undrawn yarn (ε=2.70) made of polyester multifilament (142d/72 filament) with a birefringence index △n of 0.012 was supplied to the false twisting machine shown in Fig. 2, and was twisted according to the following conditions. False-twisted. Rotation speed of false twisting spindle 300000r.pm Stretching ratio DR 2.23 Number of false twists N Left twist 4050T/M Hot pin temperature 110℃ Temperature in primary heat setting area 170℃ Temperature in secondary heat setting area 200℃ Next, perform the above as a comparative example An undrawn yarn made of the same polyester multifilament as in Example 3 was used as a material for forming the bulky yarn, and false twisting was performed according to the following processing conditions. Rotation speed of false twisting spindle 300000r.pm Stretching ratio DR 2.80 Number of false twists N 3900T/M Hot pin temperature 100℃ Primary feed rate +3.1% Temperature of primary heat setting zone 215℃ Secondary feed rate +10.0% Secondary heat Temperature in fixed area: 220℃ The primary feed rate in the above comparative example is:
The yarn supply roller in a conventional false twisting machine,
The term "secondary feed rate" refers to the yarn feed rate to the delivery roller between the false twisting spindle and the untwisting zone heater, and the term "secondary feed rate" refers to the yarn feed rate of the delivery roller to the delivery roller. Using the bulky yarn with a total denier of 65d obtained in Example 3 and the bulky yarn with a total denier of 51d obtained in the comparative example, two types of yarns having a warp density of 90/25.4 mm and a weft density of 86/25.4 mm were prepared. Manufactured Habutae textile. Thereafter, the finished product was dyed and finished under the same conditions according to a conventional method, and the physical properties of the final product were measured and the texture was evaluated by a pipe test. The measurement and evaluation results are shown in Table 1 below. In the sensory test, ◯ indicates good, △ indicates usable, and × indicates poor. 【table】

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of a second embodiment of the present invention. A, B: undrawn yarn or low drawn yarn, 1, 8:
Supply roller, 4, 12: primary heat fixing heater,
5, 14: False twisting spindle, 6, 13: Secondary heat fixing heater, 2, 10: Delivery roller,
3, 11: Winding roller, 7, 16: Bulky yarn, 1
5: Hot pin, 9: Twisting guide.

Claims (1)

[Claims] 1. When false-twisting undrawn yarn or low-drawn yarn made of polyester multifilament with a birefringence index △n of 0.008 to 0.120 while stretching,
The yarn is continuously introduced into a false twisting area, a primary heat setting area, and an untwisting/secondary heat setting area while maintaining the draw ratio DR specified by the following formula (), and in the primary heat setting area, the yarn is Row heating temperature HT ₁ is 160℃ or more
Primary heat setting is performed at 200℃, and the yarn heating temperature HT ₂ is 180℃ or higher in the above untwisting/secondary heat setting area.
220℃, _the difference between HT _{2 and} HT ₁ is 20℃
A method for producing a high bulk yarn having a silk-like texture and a high Young's modulus and low torque, the method comprising performing the above secondary heat setting together with untwisting. 0.51(1+ε)≦DR≦0.65(1+ε)() (However, ε is the breaking elongation of undrawn yarn or low-drawn yarn) 2 The number of false twists N (T/M) given to the yarn in the false twist region is A method for producing a bulky yarn having a silk-like texture according to claim 1, which is defined by the following formula (). 1.32T≦N≦1.40T ()