JP3463597B2 - Aliphatic polyester false twist yarn with excellent gloss - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aliphatic polyester temporary coating which can effectively impart bulkiness and Fuji silk-like luster to cloth such as woven and knitted fabrics while making the most of the vivid coloring properties of the aliphatic polyester. It relates to twisted yarn.

[0002]

2. Description of the Related Art Conventionally, aliphatic polyesters have been used mainly for industrial material applications because of their excellent biodegradability, but at present, they have not been specifically developed for clothing applications. is there. On the other hand, a yarn obtained by false twisting a polyester fiber made of an aromatic polyester such as polyethylene terephthalate is widely used. However, in the case of this aromatic polyester fiber, although it is a false-twisted yarn excellent in bulkiness, there is a problem that the coloring property is poor because of the high refractive index. Further, the cross-sectional deformation in the false twisting process is large and so-called glitter is generated, so that it is far from a high-quality gloss.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to suppress the cross-sectional deformation during false twisting to suppress the glossiness in order to take advantage of the characteristic of the aliphatic polyester fiber, which has a low refractive index and an excellent coloring property. It is to provide a false-twisted yarn which is excellent in bulkiness and has excellent bulkiness.

[0004]

The aliphatic polyester false twisted yarn of the present invention is an aliphatic polyester false twisted yarn having a cross-sectional change rate of 1.5 or less. Further, the preferred false twisted polyester polyester yarn of the present invention is not clouded, and the relationship between the expansion recovery ratio RS (%) and the fineness D (d) after hot water treatment is 12.5-.
0.0167 x D ≤ RS ≤ 32.5-0.0833 x D
And the hot water shrinkage is 5 to 15% or less, the primary elongation point exists in the strength-elongation curve at the time of tension, the melting point is 130 ° C. or higher, and the aliphatic polyester contains L-lactic acid as a main component. It is an aliphatic polyester false twisted yarn which is a polyester.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic polyester false twisted yarn of the present invention will be described in detail below.

The aliphatic polyester false twisted yarn of the present invention has a cross-sectional change rate of 1.5 or less. That is, this aliphatic polyester false-twisted yarn has a cross-sectional change rate of 1.5 or less, which will be described later, in order to express an excellent color forming property by utilizing the low refractive index which is an excellent physical property of the aliphatic polyester. It is a false twist yarn. Here, it has been found that glitter occurs remarkably when the cross-sectional change rate exceeds 1.5. When this glitter occurs, it is regarded as a so-called synthetic fiber-like luster, and the development of high-end clothing is restricted. Further, when a modified cross-section yarn is used as the original yarn for false twisting, the change in gloss due to the cross-sectional deformation becomes more apparent, which is not preferable. In the present invention,
The cross-sectional change rate is preferably 1.4 or less, more preferably 1.2 or less.

Here, the false twist false polyester yarn is
It is a filament having three-dimensional random crimp and torque after heat-setting in a twisted state of an aliphatic polyester multifilament. As a manufacturing method, after twisting the aliphatic polyester stretched yarn and winding it,
"Twisting-Heat fixation-Untwisting method" in which heat is set and untwisted at high temperature
In addition, there are the "false twisting method" in which heat is set and untwisted in the process of false twisting the running yarn, and the "stretching false twisting method" in which undrawn yarn is heat set while being false false twisted and then untwisted. is there. However, in order to set the cross-sectional change rate of the aliphatic polyester false twisted yarn of the present invention to 1.5 or less, the "twisting-heat setting-untwisting method" or the number of false twists or the heat setting temperature is lowered. This can be achieved by adopting a means for separating heating and twisting in the “false twist method”, the “drawn false twist method”, and the “stretch false twist method”.

The aliphatic polyester in the present invention preferably has a refractive index of 1.50 or less, and more preferably 1.45 or less, for improving color developability. Also, the melting point is 130.
When the temperature is lower than 0 ° C, the product quality becomes extremely low, such as poor drawability due to fusion between single yarns and melting defects during friction heating, which is not preferable. Therefore, in the present invention, the melting point of the aliphatic polyester is 130 ° C.
Or higher, more preferably 150 ° C. or higher, 170
C. or higher is more preferable. Here, the melting point means the peak temperature of the melting peak obtained by the DSC measurement.

The aliphatic polyester used in the present invention is not particularly limited as long as it has a refractive index of 1.50 or less and a peak temperature of a melting peak obtained by DSC measurement of 130 ° C. or more. 3-Hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxybutyrate valerate, and blends and modified products thereof can be used.

The most desirable polymer from the viewpoint of physicochemical properties is a polyester containing L-lactic acid as a main component. Having L-lactic acid as a main component means that 60% by weight or more of the constituent components are L-lactic acid, and may be polyester containing D-lactic acid in an amount not exceeding 40% by weight. .

As a method for producing polylactic acid, a two-step lactide method in which lactide which is a cyclic dimer is once produced from lactic acid as a raw material and then ring-opening polymerization is carried out, and direct dehydration condensation in a solvent using lactic acid as a raw material A one-step direct polymerization method for carrying out is known. The polylactic acid used in the present invention may be polylactic acid obtained by any production method. In the case of the polymer obtained by the lactide method, the cyclic dimer contained in the polymer vaporizes during melt spinning and causes yarn unevenness, so the cyclic dimer contained in the polymer before melt spinning is It is desirable that the body content be 0.1 wt% or less. Further, in the case of the direct polymerization method, since there is substantially no problem caused by the cyclic dimer, it can be said that it is more preferable from the viewpoint of yarn formability.

The higher the average molecular weight of polylactic acid is, the more preferable it is, and it is usually at least 50,000, preferably at least 10.
10,000, more preferably 100,000 to 300,000. When the average molecular weight is lower than 50,000, the strength and physical properties of the fiber deteriorate, which is not preferable.

Further, the polylactic acid in the present invention may be copolymerized polylactic acid obtained by copolymerizing L-lactic acid and D-lactic acid with other components having an ester forming ability. Copolymerizable components include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 6
In addition to hydroxycarboxylic acids such as hydroxycaproic acid, compounds having a plurality of hydroxyl groups in the molecule such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, polyethylene glycol, glycerin and pentaerythritol, or derivatives thereof, Contains a plurality of carboxylic acid groups in the molecule such as adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid Compounds or their derivatives are mentioned.

In order to reduce the melt viscosity, aliphatic polyester polymers such as polycaprolactone, polybutylene succinate and polyethylene succinate can be used as an internal plasticizer or an external plasticizer. Furthermore, inorganic fine particles and organic compounds as a matting agent, a deodorant, a flame retardant, a yarn friction reducing agent, an antioxidant, a coloring pigment, etc. can be added to the aliphatic polyester as required.

The melt-spinning method can be carried out by a known melt-spinning apparatus, and not only round cross-sections but also modified cross-section yarns can be manufactured by making the die holes for the corresponding modified cross-sections. For example, when obtaining a trilobal cross-section fiber, a known spinneret having a T-shaped or Y-shaped mouthpiece may be used.

The aliphatic polyester false twisted yarn according to the present invention preferably has a fiber strength of 3.0 g / d or more. If the strength is less than 3.0 g / d, it may cause fluff during yarn processing, yarn breakage, or thread breakage during weaving, or decrease in product strength due to reduction in tear strength of fabric such as woven or knitted fabric. It is not preferable because it causes

The fiber strength is more preferably 3.5 g /
d or more, and most preferably 4.0 g / d or more. As for the elongation, it is preferable to set the raw yarn and the processing conditions so that the residual elongation is about 10 to 50%, from the viewpoint of handleability during weaving and knitting and resistance to crimping.

Further, the cross section of the fiber is not limited, and it is preferable to utilize the gloss by the irregular cross section and to reduce the weight by using the hollow fiber. Similarly, the fineness is not limited,
Usually, fibers having a single yarn fineness of about 0.5 to about 10 denier are preferably used. Further, the total fineness is preferably about 20 to 450D.

Further, in the present invention, a false-twisted aliphatic polyester false twisted yarn can be obtained. When the aliphatic polyester is stretched at a low temperature at a high ratio, it may become cloudy. The cause is not clear, but it is thought that the void is involved. White turbidity, which is not due to addition of particles or dulling due to internal particles, is not preferable because it deteriorates quality due to occurrence of unevenness and deteriorates color developability. For example, in the case of L-lactic acid polyester, the yarn in the twisting region during draw false twist The temperature must be 70 ° C or higher.

As a method for judging the white turbidity, it is also possible to wind the yarn around a black plate at equal intervals, but it is difficult to eliminate the influence of particle addition, false twist crimping and glitter. After the fibers are placed on the glass surface and the liquid paraffin is hung from the fibers, the cover glass is placed on the glass surface and observed by the dark-field method using a biological microscope. In addition, even when particles are added, white turbidity can be identified by comparing with the raw yarn used for false twisting.

Further, in the present invention, the relationship between the expansion recovery ratio RS (%) and the fineness D (d) after the hot water treatment of the aliphatic polyester false twist yarn is 12.5-0.0167 × D ≦ RS ≦.
It can be 32.5-0.0833xD. As described above, it is possible to reduce the cross-sectional change rate by decreasing the false twist number and the heat setting temperature, but the crimping property is deteriorated. One way to achieve these contradictory properties is to separate the heating and twisting areas. For example, as disclosed in Japanese Patent Application Laid-Open No. 50-18710, a cross section of the cross-sectional change rate is 1. by winding a heating roller and a separate roller installed in the vicinity of the roller several times, heating and then false-twisting. It becomes possible to keep the relationship between the expansion recovery ratio after heat treatment and the fineness within the range of the above formula while suppressing the ratio to 5 or less.

Further, in the present invention, the hot water shrinkage rate of the aliphatic polyester false twisted yarn can be set to 5 to 20%. When the hot water shrinkage ratio is higher than 20%, the shrinkage is too high, so that the warp length needs to be lengthened or the weaving width needs to be widened, which makes handling difficult in the dyeing step, which is not preferable. Further, the hot water shrinkage ratio is more preferably 5 to 15%, further preferably 5 to 10%. In order to set the hot water shrinkage rate to 5 to 20%, the heat setting temperature is important, and for example, after heating several times around the heating roller shown above and a separate roller installed in the vicinity of the heating roller, This can be achieved by supplying a false twist heater set to a higher temperature and stretching false twist.

Furthermore, in the aliphatic polyester false twisted yarn of the present invention, a primary yield point as shown in FIG. The primary yield point is the maximum point of strength existing before the maximum strength at break. If this primary yield point does not exist, the strength of the false-twisted yarn is liable to decrease, and the false-twisted yarn tends to be unusable for practical use, which is not preferable. The stress at the primary yield point is preferably 0.8 g / d or more, and more preferably 1.0 g / d or more, in order to prevent stretching due to tension applied during weaving.

Next, the method for producing the false twisted polyester polyester yarn of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an example of an apparatus for processing an aliphatic polyester false twisted yarn according to the present invention. 1 is a schematic front view of the processing apparatus, and FIG. 2 is a side view thereof.

An unstretched aliphatic polyester yarn is used as the supply yarn 1, and a feed roller 2 is used to heat the heating roller 3.
The supply yarn 1 was stably supplied to. For the heating roller 3,
The supply yarn 1 is wound several times around the separate roller 4 installed near the roller, heated, and then drawn and false twisted with the drawing roller 8. By installing the nip roller 5 that rotates in contact with the heating roller 3 at the yarn separating point or upstream of the heating roller 3, it is possible to stably process the yarn. The number of yarns of the supply yarn 1 pressed by the nip roller 5 on the heating roller 3 is not limited, and one or two or more may be pressed. The temperature of the heating roller 3 may be appropriately set depending on the raw yarn used, and it is desirable to set the temperature high unless fusion, yarn breakage, and processing stability deteriorate. For example, in the case of poly L-lactic acid, 90 ° C. or lower is preferable.

The supply yarn 1 is not limited as long as it is an aliphatic polyester fiber yarn and has a stretchable residual elongation and strength. It is more preferable to install the heater 6 between the yarn separation point of the heating roller 3 and the false twist rotor 7. The heater 6 may be a dry heat heater that heats the yarn by contact or a hollow heater that heats the yarn substantially in a non-contact manner, and the set temperature may be set so that the cross-sectional change rate is 1.5 or less. For example, in the case of poly L-lactic acid,
It is preferable to set the yarn temperature to 130 ° C. or lower.

The false twist rotor 7 is not limited, but a triaxial twister or a belt nip twister is preferably used. It is preferable to add entanglement to the yarn downstream of the drawing roller 8 as necessary to improve the sizing property, in order to improve the handleability during weaving and knitting. For example, as shown in FIG. 1, the stretching roller 8 is a stepped roller, and the entanglement nozzle 9 is installed on the yarn path where the yarn is transferred from the roller having a large diameter to the roller having a small diameter, thereby saving space and improving efficiency. It is possible to give the yarn good focusing properties.

The method for producing the false twisted polyester yarn according to the present invention is not limited to the above-mentioned means, but (1) after twisting the stretched aliphatic polyester yarn, after heat setting in a heating device such as a steam setter There is a "twisting-heat setting-untwisting method" in which twisted yarn is untwisted in the opposite direction, and the uniformity of crimps, the strength of crimps, the ease of controlling the set temperature, and the temporary It is preferably used because the additional twisting step of the twisted yarn can be omitted.

(2) Using the apparatus shown in FIG. 3, for example, an aliphatic polyester stretched yarn is supplied to the feed roller 2 as the supply yarn 1, and a hollow spindle type false twisting machine or the like is used as the false twisting rotor 7. "False twisting method" in which the twisted yarn is falsely twisted, heated by the heater 6 and heat-set, then untwisted downstream of the false twisting rotor 7 and taken up by the drawing roller 8.
(3) Using an apparatus as shown in FIG. 4, an unstretched aliphatic polyester yarn is supplied as the feed yarn 1 to the feed roller 2, and the yarn is drawn by the false twist rotor 7 while being stretched between the yarn and the stretching roller 8. There is a "stretching false twisting method" in which the wire is heated by the heater 6 while being false twisted, and the twisted form is heat-set by the cooling plate 12, but these methods easily cause cross-sectional deformation. In particular, in the "stretching false twisting method", cross-section deformation is likely to occur due to twisting in the stretching process, and when adopting the above two methods, it is necessary to give sufficient consideration to the number of false twisting and the heater temperature setting.

[0031]

EXAMPLES The present invention will be described in more detail below with reference to examples.

The melting points in Examples and Comparative Examples,
Each measured value of the intrinsic viscosity and the melt viscosity is obtained by the following method.

A. Melting point Using a differential scanning calorimeter (DSC-7) manufactured by Perkin Elmer Co., Ltd., measurement was performed at a temperature rising rate of 15 ° C./min, and the peak temperature of the obtained melting peak was taken as the melting point.

B. Intrinsic viscosity (η) 0.10 sample for 10 ml orthochlorophenol
0 g was melt | dissolved and it measured at the temperature of 25 degreeC using the Ostwald viscometer.

C. Melt viscosity 260 ° C using Toyo Seiki Co., Ltd. Capirograph
The relationship between the shear rate and the melt viscosity was measured. A die with L / D = 10/1 (mm) was used for the measurement, and the viscosity at a shear rate of 1000 sec-1 was taken as the melt viscosity of the sample.

D. Cross-section change rate The false twisted yarn is cut perpendicular to the longitudinal direction of the yarn to sample a section, and a cross-sectional photograph taken by an optical microscope is taken. A value obtained by dividing the ratio of the diameter of the circumscribed circle to the diameter of the inscribed circle by the ratio of the diameter of the circumscribed circle of the supply yarn to be false twisted and the diameter of the inscribed circle is obtained for all false twisted single yarns from the cross-sectional photograph. , And its average value.

E. Hot water shrinkage ratio Measured according to JIS standard L1090-1992 5.10 Hot water shrinkage ratio A method (skein shrinkage ratio).

F. Expansion and contraction recovery rate: RS (Recovery percent)
age of Shrinkage:%) About the sample in which the false twisted yarn is left as it is for one week as a package, a small cassette is made according to JIS standard L1090-1992 5.8 expansion and contraction recovery rate, and after shrinking for 24 hours, wrapped with a sack 98 After immersing in hot water of ℃ for 30 minutes, the sample is taken out, and the sample naturally dried on filter paper for 24 hours is measured according to the 5.8 expansion and recovery rate.

G. The tensile elongation test sample at the time of tension was attached to the grip of a tensile tester with an interval of 200 mm under an initial load of 0.1 g / d, and a tensile speed of 200
The stress (g / g) for the elongation (%) of the sample at mm / min
d) was measured.

[Example 1] The melt viscosity at 260 ° C and 1000 sec ^-1 was 120.
Pa · s (1200 poise), melting point 168
Poly (L-lactic acid) (Shimadzu Corporation Rakuti 5)
000, L body ratio 95%, D body ratio 5%)
It dried for 48 hours with the vacuum dryer set to 60 degreeC. The dried chips are melted by a pressure melter type spinning machine at a melter temperature of 250 ° C., introduced into a melt pack having a spinning temperature of 260 ° C., spun out from a spinneret having a spinneret for round cross section, and an oil agent is applied. 1200m /
It was once wound in minutes to obtain an undrawn yarn. Then, after heating the obtained undrawn yarn to 80 ° C. using a heating roller,
A drawn yarn of 30 denier-36 filament which was drawn 2.3 times and heat set at 120 ° C. was obtained. The drawn yarn was subjected to S twist of 5300 T / m using a double twister and wound on a bobbin. A steam conditioner was used to once bring the vacuum state, and then steam was supplied to the bobbin to pressurize and heat it to 120 ° C. 530 heat-set twisted yarn again in Z direction
Performs twisted 0T / m, to obtain an aliphatic polyester false twisted yarn of the cross-section change rate 1.12.

Example 2 In the false twisting device shown in FIG. 1, the temperature of the heating roller 3 was set to 80 by using the undrawn yarn spun under the same conditions as in Example 1 except that only the spinneret was replaced with 12 holes. After heating at 0 ° C., 2.3 times stretching and false twisting with the stretching roller 8 were performed at a processing speed of 300 m / min. The heater 6 had a length of 200 mm and the temperature was set to 120 ° C. A triaxial twister was used as the false twist rotor, and the false twist number on the heater 6 was 5,300. Temporary twisted yarn that has been processed is 30 denier -12 filaments, sectional change rate 1.2
It was 1.

Example 3 Using the same drawn yarn of 30 denier-36 filaments as in Example 1, false twisting was carried out by the apparatus shown in FIG. The speed of the drawing roller 8 and the feed roller 2 is set to 100 m / min, the temperature of the heater 6 is 120 ° C., and the false twisting rotor has a false twisting speed of 3800 T / m. Set. Sectional change rate of the resulting aliphatic polyester false twisted yarn was 1.16. The state of the cross section is shown in FIG.

Example 4 An undrawn yarn was obtained in the same manner as in Example 1 except that the 36-hole die was changed and the discharge amount of the polymer was changed, and then false twisting was performed by the apparatus shown in FIG. . The processing conditions were such that the surface speed of the stretching roller 8 was 300 m / min, the stretching ratio was 2.3 times, and a hollow heater of 1 m was used as the heater 6, and the heating was performed at 150 ° C. A belt nip twister was used as the false twist rotor 7, and the false twist number on the cooling plate 12 was 3200 T / m.
Temporary twisted yarn that has been processed is 75 denier -36 filaments, sectional change rate was 1.24.

Comparative Example 1 Polyethylene terephthalate was melt-spun by a conventional method,
It was wound as a highly oriented undrawn yarn of 55 denier-12 filament (residual elongation 190%). Using this highly oriented undrawn yarn, false twisting was performed by the device shown in FIG. The processing conditions were as follows: the surface speed of the stretching roller 8 was 300 m / min, the stretching ratio was 1.83 times, a dry heat heater was used as the heater 6, and heating was performed at 190 ° C. A triaxial twister is used as the false twist rotor 7, and the false twist number on the cooling plate 12 is 5300T.
Was / m. Processed false twist yarn is 30 denier-12
A filament, cross-sectional change rate was 1.91.
The cross-sectional appearance of the obtained polyester false twisted yarn is shown in FIG.

Comparative Example 2 Using the same drawn yarn of 30 denier-36 filaments as in Example 1, false twisting was carried out by the apparatus shown in FIG. The speeds of the feed roller 2 and the stretching roller 8 are 70
m / min and 100m / min, set the temperature of heater 6 to 1
At 20 ° C., the rotational speed of the hollow spindle false twist was set so that the false twist number of the false twist rotor was 5200 T / m. Temporary twisted yarn that has been processed is 21 denier -36 filaments, sectional change rate was 1.55.

No white turbidity was observed in any of the processed yarns of Examples 1-5 and Comparative Examples 1-2. In addition, all the processes were stable. Table 1 shows the yarn physical properties of the aliphatic polyester false twisted yarns obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

[0047]

[Table 1] Next, warp was performed using a drawn yarn of 75 denier-24 filaments obtained by the same method as the method for producing drawn yarn shown in Example 1 (warp weave density: 123 yarns / 2. 5
4 cm), the above-mentioned Examples 1 to 3 and Comparative Example 1 as wefts
The weft density of the false twisted yarn obtained in No. 2 is 140 yarns / 2.54
cm, the false twisted yarn obtained in Example 4 was used for weft density: 90
Weaved in a book and weaved each to obtain greige (woven fabric:
2/1 Aya). The woven greige was subjected to relaxing scouring, intermediate set, dyeing, finishing set and normal dyeing process.

In Examples 1 to 4, no glitter was found,
It has a mellow luster similar to Fuji silk, and has vivid color
It had a silky texture with a squeaky feeling on the surface. Further, it has been found that it is an optimal material for a lining, for example, because it has a thick feeling and is soft. On the other hand, in Comparative Example 1, although the crimp was strong and the feeling of ground thickness was excellent, glitter was observed and the surface gloss was unfavorable. Further, in Comparative Example 2, although the degree was lower than that in Comparative Example 1, glitter appeared and the synthetic fiber-like gloss was obtained.

[0049]

EFFECTS OF THE INVENTION According to the present invention, in order to prevent the generation of glitter due to the cross-sectional deformation caused by false twisting, a false twisted yarn having a cross-sectional change rate of 1.5 or less is used to obtain a mellow luster similar to that of Fuji silk. A bulky woven or knitted product can be obtained. Also, in addition to the excellent color development of aliphatic polyester due to its low refractive index and the silky-like texture due to the squeaky feeling that aliphatic polyester has, it becomes possible to impart bulkiness and stretchability to woven and knitted fabrics, making it possible to use conventional biodegradation. It is possible to widely expand the aliphatic polyester, which is mainly used for industrial materials, to the field of clothing materials such as linings, the field of general clothing, and further the use of high-grade clothing by utilizing its properties.

[Brief description of drawings]

FIG. 1 is a schematic front view for explaining an example of a drawn false twisting apparatus according to the present invention.

FIG. 2 is a schematic side view of FIG.

FIG. 3 is a schematic diagram for explaining an example of a false twisting apparatus according to the present invention.

FIG. 4 is a schematic view for explaining another example of the drawn false twisting apparatus according to the present invention.

FIG. 5 shows a strength-elongation curve when a tensile test is performed on the false twisted polyester polyester of the present invention.

FIG. 6 is a diagram showing a cross-sectional appearance of the false twisted polyester polyester yarn obtained in Example 3;

FIG. 7 is a view showing a cross-sectional appearance of the aliphatic polyester false twisted yarn obtained in Comparative Example 1.

[Explanation of symbols]

1: Supplied yarn 2: Feed roller 3: Heating roller 4: Separate roller 5: Nip roller 6: heater 7: False twist rotor 8: Stretching roller 9: Entanglement nozzle 10: Spindle type winding device 11: Relax roller 12: Cooling plate 13: Winder

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-323684 (JP, A) JP-A-7-300520 (JP, A) JP-A-9-209222 (JP, A) JP-A-10- 292237 (JP, A) JP-A-9-59834 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) D02G 1/02 D01F 6/62

Claims (7)

(57) [Claims] 1. A false twisted yarn made of an aliphatic polyester fiber yarn, wherein the cross-sectional change rate is 1.5 or less. 2. The method according to claim 1, which is not clouded.
The false polyester false twisted yarn described. 3. The relationship between expansion and recovery rate RS (%) after hot water treatment and fineness D (d) is 12.5-0.0167 × D ≦ RS ≦.
32.5-0.0833xD, The false twist false polyester yarn of Claim 1 or 2 characterized by the above-mentioned. 4. The aliphatic polyester false twist yarn according to any one of claims 1 to 3, which has a hot water shrinkage of 5 to 15%. 5. The aliphatic polyester false twisted yarn according to claim 1, wherein a primary yield point is present in the strength-elongation curve during tension. 6. The aliphatic polyester false twist yarn according to claim 1, which has a melting point of 130 ° C. or higher. 7. The aliphatic polyester constituting the aliphatic polyester fiber yarn is a polyester containing L-lactic acid as a main component, according to claim 1.
Parasitic false twisted polyester yarn according to item.