JP3520848B2 - Polyester yarn and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester yarn made of polytrimethylene terephthalate and a method for producing the same. More specifically, it is possible to stably produce a yarn without winding tightness in high-speed yarn production and to obtain physical properties in the longitudinal direction of the fiber. The present invention relates to a polyester yarn having a small variation, a small tightening feeling due to expansion and contraction with a low modulus when formed into a cloth, and a soft texture, and a method for producing the same.

[0002]

2. Description of the Related Art Polytrimethylene terephthalate fibers are excellent in elastic recovery after stretching, have a low Young's modulus and soft bending properties, have good dyeability, and have chemically stable properties similar to polyethylene terephthalate. is doing. Therefore, it has been studied for a long time as a material for clothing, as seen in Japanese Patent Laid-Open Nos. 52-5320 and 52-8124.

However, since the raw material 1,3-propanediol is relatively expensive, it has not been used as a synthetic fiber until now.

In recent years, US Pat. No. 5,304,69
As disclosed in the specification No. 1, etc., cheap 1,3
-The value of polytrimethylene terephthalate fibers has been reviewed as a synthetic process for propanediol was discovered.

However, according to the study by the present inventors, when the two-step method generally used for polyethylene terephthalate fiber is applied to polytrimethylene terephthalate fiber as it is, the internal structure starts to change immediately after spinning, so-called. Since a phenomenon called winding tightness causes a difference in physical properties between the inner layer and the outer layer of the package due to a difference in the amount of change in the internal structure, stable quality fibers cannot be obtained.

As a means for solving this, Japanese Patent Laid-Open No. 52-8
As disclosed in Japanese Patent No. 123, 123, there has been proposed a method using a DSD in which a spinning process and a drawing process are continuously performed and a fiber internal structure is heat-fixed before winding. However,
Even with this method, winding tightness could not be completely suppressed.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a polyester which has a stable quality without winding tightness in a yarn making process, has a low Young's modulus in an elastic recovery region and is excellent in soft stretchability and flexibility. It is an object of the present invention to provide a yarn and a manufacturing method thereof.

[0008]

To solve the above-mentioned problems, the polyester yarn of the present invention mainly has the following constitution. That is, a multifilament yarn made of polytrimethylene terephthalate, having a stress-strain curve strength of 3 cN / dtex or more and a Young's modulus of 25 cN / dtex or less and an elongation of 3 to 10
%, The minimum differential Young's modulus is 5 cN / dtex or less, the elastic recovery rate after 10% elongation is 90% or more, and the continuous shrinkage rate CV% in the longitudinal direction of the yarn is 4% or less. And polyester thread.

The woven fabric of the present invention mainly has the following constitution. That is, the polyester yarn is twisted with a twist coefficient of 100.
A woven fabric excellent in soft stretchability, characterized in that it is used as a warp yarn and / or a weft yarn with a twisted yarn of 0 to 20000.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

The polyester yarn of the present invention is a multifilament consisting essentially of polytrimethylene terephthalate.

In the present invention, the polyester constituting the polyester yarn has a polytrimethylene terephthalate (at least 90 mol% of its constitutional unit) obtained by using terephthalic acid as a main acid component and 1,3-propanediol as a main glycol component. Hereinafter abbreviated as PTT)
Is. However, 10 mol%, more preferably 6 mol%
Other copolymerizable components capable of forming an ester bond may be contained in the following proportions. Further, as the copolymerizable compound, for example, isophthalic acid, succinic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, 5-
Dicarboxylic acids such as sodium sulfoisophthalic acid,
Examples thereof include, but are not limited to, diols such as ethylene glycol, diethylene glycol, dipropylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol, polyethylene glycol and polypropylene glycol. Further, titanium dioxide as a matting agent, fine particles of silica or alumina as a lubricant, a hindered phenol derivative as an antioxidant, a coloring pigment and the like may be added, if necessary.

The strength of the polyester yarn of the present invention is 3
It is important that it is not less than cN / dtex. Strength is 3
When it is less than cN / dtex, fluffing, yarn breakage, etc. are induced in a higher-order processing step such as weaving, and only the obtained product has low tear strength.

Further, there is an inverse correlation between the breaking elongation and the occurrence frequency of fluff during weaving, and the higher the breaking elongation while satisfying the practical strength, the more the occurrence of fluff can be suppressed. Therefore, the residual elongation is preferably 40% or more, more preferably 45% or more.

It is important that the polyester yarn of the present invention has a Young's modulus of 25 cN / dtex or less and a minimum differential Young's modulus of 5 cN / dtex or less at an elongation of 3 to 10%. All of these properties are closely related to the elongation property and elastic recovery property of the stretch fabric, and it is preferable that all of these properties have low values in order to satisfy the soft stretch which is the object of the present invention. That is,
By satisfying all of the above characteristics, initial tension is easily obtained when the cloth is formed (low Young's modulus), and further, it is stretched without resistance even in the range of elongation of 3 to 10% which is a practical stretch recovery area. Since it has a low differential Young's modulus), a soft stretch fabric having excellent wearing comfort can be obtained.

The Young's modulus is also proportional to the flexural rigidity of the fabric, and the lower the Young's modulus, the more excellent the texture. Therefore, the Young's modulus is preferably 22 cN / dtex or less, and more preferably 20 cN / dtex or less.

[0017]

Further, the polyester yarn of the present invention is 10%.
The elastic recovery rate after stretching is 90% or more. If the elastic recovery rate is less than 90%, a defect called "warp", in which a part that is partially plastically deformed remains after being stretched, and the quality of the woven fabric deteriorates. The elastic recovery rate after 10% elongation is preferably 95% or more, more preferably 98% or more.

By the way, the fact that the yarn made of PTT is excellent in elastic recovery is largely due to its molecular structure. P
In the crystal structure of TT, since the methylene chain of the alkylene glycol part has a gauche-gauche structure, the interaction due to stacking of benzene rings is low, the density is low, and the flexibility is high, the alkylene glycol part is It is considered that the molecular chain easily extends and recovers due to the rotation of the methylene chain.

Further, according to the experiments conducted by the present inventors, it has been found that the higher the crystallinity, the higher the elastic recovery. Therefore, the crystallinity is preferably 30% or more, more preferably 35% or more. Here, the crystallinity is measured according to JIS
L1013 (chemical fiber filament yarn test method) 7.
It is obtained by the density according to the density gradient tube method of 14.2.

The polyester yarn of the present invention has a boiling water shrinkage of 3 to 15%, and a maximum shrinkage stress of 0.
It is preferable that the temperature is 3 cN / dtex or less and the temperature at which the maximum value of the shrinkage stress is 120 ° C. or more.

The boiling water shrinkage rate is one of the most important factors in designing a fabric, and setting the boiling water shrinkage rate to 3% or more improves the setting property in the high-order process,
By setting the content to 15% or less, it is possible to obtain a fabric having a soft texture with no coarse and hard feeling. Similarly, if the heat shrinkage stress is too high, excessive shrinkage will occur, resulting in a rough and hard texture. Therefore, the maximum value of the contraction stress is preferably 0.3 cN / dtex or less in order to obtain a soft texture without rough feeling, and 0.15 to 0.25 cN / d is preferable.
More preferably, it is tex. Further, the temperature at which the maximum value of the shrinkage stress is 120 ° C. or higher, more preferably 130 ° C. or higher in order to facilitate higher-order processing such as setting and bulking up.

It is important that the polyester yarn of the present invention has a CV% of continuous shrinkage in the longitudinal direction of the yarn of 4 % or less.
Is . The continuous shrinkage CV% is one of the indexes showing the homogeneity of the internal strain in the yarn longitudinal direction, and the smaller this value is, the higher the quality is .

The polyester yarn of the present invention is preferably subjected to entanglement treatment and has a CF value in the range of 1-30. By setting the CF value to 1 or more, single yarn breakage during yarn making, yarn processing, and weaving can be suppressed. Further, by setting the CF value to 30 or less, for example, when the fibers are mixed as one side yarn of the shrinkage differential mixed fiber, the migration property is improved, which is preferable. The CF value is more preferably 5 to 25.

The cross-sectional shape of the fibers constituting the polyester yarn of the present invention may be a round cross section, a triangular cross section, a multi-lobal cross section, a flat cross section, an X-shaped cross section, or any other known irregular cross section, without any limitation. It is not a matter of matter, and it may be appropriately selected according to the purpose.

In order to improve the flexibility of the woven fabric, the single fiber fineness is preferably 5 dtex or less, more preferably 3 dtex or less.

By the way, the polyester yarn of the present invention has a strong correlation between the twisting coefficient and the stretchability, and when the twisting coefficient exceeds a certain level, the stretchability tends to be rapidly improved. In fact, the stretch ratio of a woven fabric using a yarn having a twist coefficient of about 5000 is about 5%, but a twist coefficient of 100
At 00, the stretch ratio improves to about 15%, and at a twist coefficient of 14000, the stretch ratio improves to about 30%. Therefore, the polyester yarn obtained in the present invention may be used as it is without twisting, but the twisting factor is 100.
More preferably, it is a medium twist to a strong twist of 00 to 20000.

The twist coefficient K is expressed by K = T × D ^0.5 .

Here, T: number of twists per 1 m of yarn length, D: fineness of yarn (decitex) Here, the number of twists per 1 m of yarn length is 90 × 10 ⁻³ cN / with an electric twisting machine. It is a value obtained by untwisting under a load of dtex and untwisting when completely untwisted, divided by the yarn length after untwisting.

The fabric form of the present invention can be appropriately selected according to the purpose, such as woven fabric, knitted fabric, non-woven fabric, and cushioning material, and can be suitably used for shirts, blouses, pants, suits, blouson and the like.

Next, an example of the method for producing the polyester yarn of the present invention will be described.

P as the main raw material of the polyester yarn of the present invention
As a method for producing TT, a known method can be used as it is. The intrinsic viscosity [η] of the PTT used is 0.7 in order to improve the spinnability during spinning and obtain a yarn of practical strength.
It is important that it is not less than 0.8, preferably not less than 0.8.

The polyester yarn of the present invention may be polymerized and then spun and drawn as it is by continuous spinning, or it may be once made into chips and then dried and spun and drawn.

The spinning temperature for melt spinning is 10 than the melting point of PTT in order to stabilize the discharge with the spinneret.
It is preferable to carry out at a temperature higher by -60 ° C, and the melting point + 20-
It is more preferable to carry out at 50 ° C. In addition, in order to suppress oligomer precipitation in spinning and improve spinnability, a heating cylinder or suction device of 2 to 20 cm below the spinneret, air for preventing polymer oxidation deterioration or spinneret stain, nitrogen, etc., as necessary under the spinneret. You may install the inert gas generators, such as.

In producing the polyester yarn of the present invention, the most important thing is to employ a direct spinning / drawing method in which after spinning, the yarn is immediately drawn without being wound.

As described above, the undrawn yarn made of PTT undergoes a phenomenon called so-called winding tightening, in which the internal structure starts to change immediately after spinning, and this causes a difference in physical properties between the inner and outer layers of the package. Therefore, the inventors of the present invention studied to suppress the winding tightness. As a result, after the film was taken up at a spinning speed of 2000 m / min or more, the film was continuously drawn and heat-treated without being once taken up, and the relaxation rate was continuously 5 to 5. It has been found that the method of performing the relaxation heat treatment at 20% is effective. By using this method, tightness of winding can be greatly improved and high quality yarn with very small difference between the inner and outer layers of the package can be obtained. It has also been found that by performing relaxation heat treatment with a high relaxation rate, a soft stretch yarn having a low Young's modulus in the elongation recovery region and being easily stretched can be obtained.

Here, the spinning speed is 2000 m / m in order to obtain a uniform yarn in which the yarn unevenness is small and defects such as dyeing unevenness hardly occur.
It is important to make it more than a minute. By increasing the spinning speed, the tension on the spinning line is increased, and by making it less susceptible to the influence of disturbance, the thinning behavior becomes stable. Therefore, the spinning speed is more preferably 3000 m / min or more. In order to secure more stable spinnability, the spinning speed is preferably 6000 m / min or less.

Further, the stretching ratio is such that fluffing in the stretching region
The residual elongation is 40 in order to suppress breakage and to stably produce yarn.
It is preferable to set it to be not less than%.

The relaxation rate during the relaxation heat treatment after stretching is
To obtain the polyester yarn which is the object of the present invention, 6-2
It is important to make it 0%. After stretching, the strain inside the fiber can be rapidly relaxed by performing a relaxation heat treatment of 6% or more, so that the delayed relaxation amount of the residual strain is reduced,
Winding tightness is suppressed. Furthermore, as described above, the relaxation heat treatment facilitates elongation in a practical elongation region (elongation of 10% or less), and imparts characteristics excellent in soft stretchability. More preferably, the relaxation rate is 8% or more. On the other hand, the relaxation rate is preferably 20% or less in order to secure the running stability of the yarn in the yarn making process.
% Or less is more preferable.

Here, a method of performing the relaxation heat treatment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a schematic view of a method using a cold roll for the relaxation heat treatment. The yarn discharged from the spinneret 1 is cooled by the chimney 2 and then converged by the oil supply guide 3 and applied with an oil agent. After being taken up by the first hot roll 4 and heated, it is stretched and heat-fixed between the first hot roll 4 and the second hot roll 5. After the drawing step, the heat of the second hot roll 5 is used to perform a relaxation heat treatment between the second hot roll 5 and the cold roll 6, and the roll is wound by the winder 8. In order to perform the relaxation heat treatment more efficiently, a heat treatment apparatus using heated air or steam as a heat medium is used between the second hot roll 5 and the cold roll 6, or a third hot roll is installed to perform two steps. It is also an effective means to achieve the object of the present invention to perform the relaxation treatment with.

FIG. 2 is a schematic view of a method in which an entanglement nozzle is used for the relaxation heat treatment, and the entanglement nozzle 7 functions as a yarn cooling device and a tension gradient control. That is, since the yarn tension before the entanglement can be reduced by the entanglement treatment, the contraction stress generated by the heat of the second hot roll 5 is used to perform the relaxation heat treatment between the second hot roll 5 and the entanglement nozzle 7. You can In this case, the relaxation rate can be controlled by changing the working air pressure of the confounding nozzle. Further, a heat treatment device using heated air or steam as a heat medium may be used between the second hot roll 5 and the confounding nozzle 7, or a third hot roll may be installed to perform the relaxation treatment in two stages.

In this method, it is easy to control the relaxation rate,
It is a method preferably used for obtaining the polyester yarn of the present invention.

[0044] The heating roll which also serves as a stretching and heat setting and relaxation heat treatment (Fig. 1, in the example of FIG. 2, the second hot roll) is intended to use a satin roll surface roughness 1.5S~8S There is . The surface roughness is a section value of the maximum height (Rmax) described in JIS B0601, which is 1.5S to
8S actually corresponds to the segment values of 1.6S, 3.2S, and 6.3S. Also, it has a maximum height of 0.8 μm.
Corresponding to 6.3 μm or less. The surface roughness was 1.
When it is 5 S or more, the coefficient of friction between the yarn and the roller is significantly reduced and the yarn slips moderately, so that the yarn can be stably produced without reverse winding around the heating roll even at a high relaxation rate. The higher the surface roughness, the more stable the running yarn in the relaxation step, but if the surface roughness exceeds 8S, the yarn surface is excessively rubbed, resulting in a decrease in strength. A more preferable surface roughness of the heating roll is 3.2S to 6.3S (Rmax:
1.7 to 6.3 μm). The surface roughness was measured according to JIS B0601 by measuring the maximum height Rmax using a Hommel Tester T1000 type manufactured by Hommel.

Stretching temperature (first hot roll temperature)
Is preferably higher than the glass transition point of PTT by 10 to 50 ° C., and more preferably at a glass transition point +20 to 40 ° C., in order to stably produce a yarn without yarn breakage. Heat setting and relaxation heat treatment temperature (second hot roll temperature) is 9
It may be set so as to obtain a desired heat shrinkage ratio in the range of 0 to 180 ° C, but it is more preferably set to 105 to 180 ° C in order to relax the residual strain formed by stretching without unevenness.

Further, the spinning oil is provided with a smoothing agent, an emulsifier, an antistatic agent and the like. Specifically, mineral oils such as liquid paraffin, fatty acid esters such as octyl palmitate, lauryl oleate and isotridecyl stearate, dibasic acid diesters such as dioleyl adipate and dioctyl sebacate, trimethylolpropane trilaurate. , Polyhydric alcohol esters such as coconut oil, aliphatic sulfur-containing esters such as lauryl thiodipropionate, polyoxyethylene oleyl ether, polyoxyethylene castor oil ether, polyoxyethylene nonylphenyl ether, trimethylolpropane trilaurate, etc. Nonionic surfactants, metal salts such as alkyl sulfonates and alkyl phosphates, anionic surfactants such as amine salts, dioctyl sulfosuccinate sodium salt, alkane sulfonate sodium salt, etc. Tylene oxide / ethylene oxide copolymer, propylene oxide / ethylene oxide copolymer, nonionic surfactant, etc. can be mentioned. Each process of yarn making, warping and weaving, especially the reedability at the time of weaving, the passage of heddle Adopt a prescription that improves If necessary, further rust inhibitor, antibacterial agent, antioxidant, penetrant, surface tension lowering agent, phase inversion viscosity lowering agent,
An antiwear agent and other modifiers are used together.

The amount of oil adhered is 0.3 to 1.2 with respect to the yarn.
It is preferable that the content is wt% from the viewpoint of high-order process passability.

[0048]

The present invention will be described in more detail with reference to the following examples. Each characteristic value in the examples was obtained by the following method. A. Intrinsic viscosity [η] Dissolve a sample polymer in orthochlorophenol (hereinafter abbreviated as OCP), determine relative viscosity ηr at a plurality of points using an Ostwald viscometer at a temperature of 25 ° C, and apply it to an infinite dilution outer layer. I asked. B. Tensile strength and Young's modulus (initial tensile resistance) samples were made by Orientec Co., Ltd., TENS.
The measurement was carried out using ILON UCT-100 under the constant speed elongation conditions specified in JISL1013 (chemical fiber filament yarn test method). The breaking elongation was obtained from the elongation at the point showing the maximum strength in the SS curve.

The Young's modulus was measured under the conditions shown in JIS L1013 (Chemical fiber filament yarn test method) 7.10 Initial tensile resistance. C. The differential Young's modulus was obtained by differentiating the stress at each point of the SS curve obtained by the B term by the elongation. D. Elastic recovery sample is TENSILON U manufactured by Orientec Co., Ltd.
Using CT-100, gripping interval 20 cm, pulling speed 1
Elongation was performed at 0 cm / min up to 10% of the gripping interval, the weight was immediately removed at the same speed, and the elastic recovery rate was obtained from the recorded hysteresis curve.

Elastic recovery rate (%) = (β / α) × 100 α: elongation at 10% elongation β: recovery elongation to the point where the stress became equal to the initial load E. Shrinkage stress A thermal stress measuring instrument manufactured by Kanebo Engineering Co., Ltd.
It was measured at a temperature rising rate of 2.4 ° C./sec. Sample is 10 cm
X2 loop with initial tension of fineness (decitex) x
It was 0.9 × (1/30) gf. F. CV% of continuous shrinkage in the longitudinal direction of the yarn Using FTA500 manufactured by Toray Engineering Co., Ltd.,
Set tension to fineness (decitex) x 0.9 x (1/6
0) gf, processing temperature 100 ° C (under steam), yarn speed 10
The shrinkage percentage was recorded on a chart by measuring at m / min and a sample length of 10 m, and the CV% of the continuous shrinkage percentage in the yarn longitudinal direction was determined. G. CF value JIS L1013 (chemical fiber filament yarn test method) was measured under the conditions shown by the degree of entanglement of 7.13. The number of tests was 50, and the CF value (Coherence Factor) was calculated from the average value L (mm) of the confounding length by the following formula.

CF value = 1000 / L H.V. Crystallinity The density is measured according to the density gradient tube method of JIS L1013 (chemical fiber filament yarn test method) 7.14.2,
The crystallinity was calculated by the following formula.

Xc [%] = {dc × (d-da)} /
{D × (dc-da)} × 100 Xc: Crystallinity (%) d: Measured yarn density dc: Density of completely crystalline part da: Density of completely amorphous part where dc: 1.387 g / cm ³ , Da: 1.29
5 g / cm ³ was used.

Example 1 Using the spinning / drawing machine shown in FIG. 1, the intrinsic viscosity [η] was 0.9.
Homo PTT of No. 6 was melted, discharged from the spinneret 1 having 24 holes at a spinning temperature of 265 ° C., cooled by the chimney 2, converged by the oiling guide 3, and applied with an oil agent, and then 30 by the first hot roll 4.
The yarn was taken up at 00 m / min, and the yarn was heated at 70 ° C. for 5 turns to raise the temperature of the yarn.
Stretching at m / min (stretching ratio 1.6 times), making 5 cycles at 140 ° C. and heat setting, further relaxing at a relaxation rate of 10% between the second hot roll 5 and the cold roll 6, and then entanglement Winding at 4220 m / min by the winder 8 while performing confounding treatment with the operating pressure and air pressure of 0.2 MPa using the device 7, 54
A decitex, 24 filament drawn yarn was obtained. The second hot roll 5 has a surface roughness of 3.2S (Rmax
: 3 μm) satin roll was used.

The yarn-forming property was good, and yarn breakage and single winding did not occur. The obtained polyester yarn has a strength of 3.6 cN / dtex, a Young's modulus (initial tensile resistance) of 20.8 cN / dtex, and a minimum differential Young's modulus of 1.8 cN / d at an elongation of 3 to 10%. The elastic recovery rate after dtex and 10% elongation was 97.8%. Table 1 shows the physical properties.
The stress-strain curve and differential Young's modulus-strain curve are shown in FIG.

Further, as a result of weaving the multifilament yarn with four-way twill by using warp / weft, it was found that the weavability and the quality of the woven fabric were good, and it had a light stretchability.

Examples 2 and 3 Stretching speeds of 4350 m / min (stretching ratio 1.45 times) (Example 2) and 5000 m / min (stretching ratio 1.67 times)
Example 3 was carried out under the same conditions as Example 1 except that (Example 3). The polyester yarn of Example 2 has a strength of 3.3 cN / dt.
ex was lower than that of Example 1, but other properties were good as in Example 1. Further, the polyester yarn of Example 3 had about twice the number of stops during weaving as compared with Example 1, but the other properties were good.

ExampleFour Relaxation rate between second hot roll 5 and cold roll 6
18% (ExampleFourThe same conditions as in Example 1 except that
It was carried out in. ExampleFourThe same polyester thread as in Example 1
, The yarn-forming property and the textile quality are good, and it is a light stretch.
Have sexCageMore flexible than Example 1.
I was there.

Comparative Example 1 It was carried out under the same conditions as in Example 1 except that homo PTT having an intrinsic viscosity [η] of 0.68 was used. The polyester yarn of Comparative Example 1 had poor spinnability, and many yarn breakages occurred in the drawing zone, making it impossible to sample.

Comparative Example 2 The same conditions as in Example 1 were used except that the stretching speed was 3900 m / min (stretching ratio 1.3 times). The polyester yarn of Comparative Example 2 has a strength of 2.9 cN / dtex and an elongation of 73.5.
%, Low strength and high elongation, the elastic recovery rate after 10% elongation was low, and the practical durability after forming a fabric was poor.

Comparative Examples 3 and 4 The same conditions as in Example 1 were used except that the relaxation rate between the second hot roll 5 and the cold roll 6 was 22%, and the relaxation rate was 3%. did. In the polyester yarn of Comparative Example 3 in which the relaxation rate was 22%, the yarn was greatly shaken on the second hot roll, and the yarn was wound around the second hot roll and broken.

In Comparative Example 4 with a relaxation rate of 3%, a difference in physical properties occurs between the inner layer of the package and the outer layer due to the occurrence of winding tightness, resulting in a thick and thin shape corresponding to the cycle of the end face of the package, and further poor weaving properties, and the dyed product. Was of poor quality. In addition, although the fabric had stretchability, it exhibited stretchability that was extremely difficult to stretch. Physical properties are shown in Table 1, and stress-strain curve and differential Young's modulus-strain curve are shown in FIG.

Comparative Example 5 The same procedure as in Example 1 was carried out except that the stretching speed was 5250 m / min (stretching ratio 1.75 times), and the cold roll 6 was removed so that the relaxation rate was 0%. In Comparative Example 5, the tightness of winding was worse than in Comparative Example 4, and the obtained fabric had stretch characteristics that were extremely difficult to stretch and was inferior in flexibility.

Comparative Example 6 The speed of the first hot roll 4 was 1000 m / min, and the speed of the second hot roll 5 was 3500 m / min (stretching ratio 3.5.
Was performed under the same conditions as in Example 1. Comparative The fabric made of the polyester yarn of Example 6 was the same as in Example 1.
Although it showed good stretch characteristics, dyed spots were formed on the dyed cloth, which are thought to be due to yarn unevenness.

Comparative Example 7 The same conditions as in Example 1 were applied except that the second hot roll 5 was changed to a 0.8S (Rmax: 0.8 μm or less) mirror surface roll. In Comparative Example 7, the traveling yarn in the relaxation zone between the second hot roll and the cold roll 6 is unstable,
Frequently, a spiking occurred on the second hot roll, which developed into reverse winding and the yarn was broken. Therefore, the number of yarn breakages was about 10 times that of Example 1.

Example5 2000 t / m (twisting agent) was added to the polyester yarn obtained in Example 1.
S / Z twist of several K: 14700) and warp and weft
As a yarn, a 4-ply twill fabric was prepared. This is 98 by the conventional method.
Relax scouring at ℃, intermediate setting at 160 ℃, then 3
15% by weight with a hot NaOH aqueous solution, and dyeing
I gave a set finish. The resulting fabric is soft and
And stretchability were extremely excellent.

[0066]

[Table 1] In the table, "relaxation rate" means "relaxation rate between second hot roll and cold roll 6", and "differential Young's modulus" means "elongation of 3 to 10%".
"The minimum value of the differential Young's modulus at" is the "elastic recovery rate"
"Elastic recovery rate after 10% elongation" means "shrinkage stress"
"Maximum value of shrinkage stress", "peak temperature" means "temperature showing maximum value of shrinkage stress", and "shrinkage CV%" means
"CV% of continuous shrinkage in the yarn longitudinal direction" is defined as "woven fabric quality"
Means "the appearance quality of the woven fabric after dyeing (sensory evaluation)".

[0067]

INDUSTRIAL APPLICABILITY The polyester yarn of the present invention and the method for producing the same are a package of stable quality without winding tightness in the yarn making process, have a low Young's modulus in the elastic recovery region, and are excellent in soft stretchability and flexibility. It is possible to obtain a woven fabric.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a spinning / drawing device for obtaining a polyester yarn of the present invention.

FIG. 2 is a schematic view showing another example of the spinning / drawing apparatus for obtaining the polyester yarn of the present invention.

FIG. 3 is a stress-strain curve and a differential Young's modulus-strain curve of the polyester yarn of the present invention (Example 1).

FIG. 4 is a stress-strain curve and a differential Young's modulus-strain curve of a polyester yarn other than the present invention (Comparative Example 4).

[Explanation of symbols]

1: Spinneret 2: Chimney 3: Refueling guide 4: 1st hot roll 5: Second hot roll 6: Cold roll 7: Entanglement nozzle 8: Winding machine

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-11-93037 (JP, A) JP-A-6-280113 (JP, A) JP-A-2000-178828 (JP, A) International Publication 99/027168 ( WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) D01F 6/62 D03D 15/00

Claims (8)

(57) [Claims] 1. A multifilament yarn made of polytrimethylene terephthalate, having a stress-strain curve strength of 3 cN / dtex or more and a Young's modulus of 25.
In addition to cN / dtex or less, the minimum differential Young's modulus at an elongation of 3 to 10% is 5 cN / dtex or less, the elastic recovery rate after 10% elongation is 90% or more, and continuous shrinkage in the yarn longitudinal direction. A polyester yarn having a CV% of 4% or less. 2. The polyester yarn according to claim 1, which has a crystallinity of 30% or more. 3. A boiling water shrinkage ratio of 3 to 15%, a maximum shrinkage stress value of 0.3 cN / dtex or less, and a temperature at which the maximum shrinkage stress value is 120 ° C. or more. The polyester yarn according to claim 1. 4. The polyester yarn according to claim 1, having a CF value of 1 to 30. 5. A woven fabric characterized by using the polyester yarn according to any one of claims 1 to 4 as a twisted yarn having a twist coefficient of 10,000 to 20,000 and used as a warp and / or a weft. 6. A multifilament yarn obtained by melt spinning a polymer of polytrimethylene terephthalate having an intrinsic viscosity [η] of 0.7 or more, is drawn at a spinning speed of 2000 m / min or more, and is not wound once. Subsequently, after stretching and heat treatment using a satin roll having a surface roughness of 1.5S to 8S, relaxation heat treatment is continuously performed at a relaxation rate of 6 to 20%,
A method for producing a polyester yarn, which comprises winding the polyester yarn into a package. 7. The method for producing a polyester yarn according to claim 6, wherein a cold roll is provided between the draw roll and the winder, and relaxation heat treatment is performed between the draw roll and the cold roll. 8. The method for producing a polyester yarn according to claim 6, wherein an entanglement nozzle is provided between the drawing roll and the winding machine, and relaxation heat treatment is performed between the drawing roll and the entanglement nozzle.