JPH0680207B2 - Polyester thick yarn and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention has a large and small thickness in the longitudinal direction of the yarn, and particularly when it is made into a raw yarn woven or knitted fabric with a soft twist or no twist, it exhibits a good appearance, quality and feel. The present invention relates to a polyester thick yarn and a method for producing the same.

[Prior art and its problems]

It is a well-known technique to non-uniformly draw a polyester unstretched yarn to make a yarn thick and thin in the longitudinal direction of the yarn. However, the thick yarns obtained by simply non-uniform stretching usually have an extremely high boiling water shrinkage rate of 50 to 80%, and when used as a woven or knitted fabric, the shrinkage during scouring and dyeing is too large and abnormally high. Only the texture with a hard density can be obtained.

That is, in order to obtain a proper woven or knitted fabric, it is necessary to further reduce the shrinkage ratio, and for this reason, the present inventor has proposed that the method disclosed in JP-A-57-112.
428, JP-A-57-139514 and JP-A-57-143
In Japanese Patent No. 515, etc., a technique for reducing the shrinkage ratio has been proposed by subjecting a polyester multifilament yarn having a large thickness to a relax heat treatment. However, when these technologies are examined in detail, the boiling water shrinkage in the longitudinal direction of the yarn greatly varies, and therefore, when the raw silk woven or knitted product is refined, puckering ring-shaped unevenness frequently occurs, resulting in poor woven or knitted article position. It has been found. In the relaxation heat treatment, the heating body inlet guide is indispensable to regulate the yarn path on the heating body,
The contact state of the yarn to the heating element due to the intermittent tamari of the untwisting of the undrawn yarn supplied to the drawing on this guide when the boiling water shrinkage rate of the heating element is drastically reduced by several tens of percent. Of the boiling water shrinkage in the longitudinal direction of the yarn is large due to the change in the length direction of the yarn and the large fluctuation of the yarn on the heating body. The variation in boiling water shrinkage in the longitudinal direction of the yarn is particularly remarkable in the modified cross-section yarn.

In addition, Japanese Patent Laid-Open No. 51-147616 discloses polyester thick yarn.
Technology for producing a yarn having a clear thick and thin effect when a false twisted yarn is obtained by performing a tension heat treatment at a tension ratio of 0.95 to 1.15, and JP-A-57-191.
Japanese Unexamined Patent Publication No. 340 discloses a technique in which a thick polyester yarn is heat-treated at a draw ratio of 0.95 to 1.05 to form a yarn having a small thermal deterioration. However, even in the tension heat treatment, the yarn path regulation guide is indispensable to prevent the yarn fluctuation on the heating body.
If it is less than about 1.05, it is substantially the same as the relaxation heat treatment, and the above-mentioned drawbacks cannot be avoided.On the other hand, if the tension ratio is about 1.05 or more, the thick part of the thick yarn supplied to the tension heat treatment changes in detail and the thinning effect decreases. In addition to the above, it is unavoidable that the thick portion is intermittently elongated, a new thick and thin structure is formed, and the variation in boiling water shrinkage in the longitudinal direction of the yarn is large.

Japanese Patent Publication No. 58-4092 discloses a polyester multifilament in which unstretched parts are randomly distributed along the length direction of each filament and the unstretched parts are 5 to 80% in an arbitrary cross section. Since the unstretched parts are randomly distributed and there are always unstretched parts in every part of the entire yarn, the difference in dyeing density in the yarn length direction is small, and the difference in dyeing density in knitted fabrics is small. There is a drawback that the frost effect based on is small. Further, the technique disclosed in this publication has a large fluctuation rate of boiling water shrinkage in the longitudinal direction of the yarn, and causes unevenness in the woven or knitted fabric, particularly in the raw yarn woven or knitted fabric, resulting in poor quality. The publication describes that when a woven or knitted fabric is dyed, a delicate grain appears, and the span has a texture like that. However, in the raw silk woven or knitted fabric, this delicate grain becomes a defect that the quality is not impaired.

Japanese Unexamined Patent Publication (Kokai) No. 57-171717 discloses a polyester multifilament having irregular irregularities in the longitudinal direction and a large number of stretched single yarns in order to obtain a woven or knitted fabric having natural irregularities of silk tone. Plaques are disclosed. It is specified that the number of stretched fibers is 45% or more and the number of unstretched fibers is 30% or less in the spots, and because the proportion of unstretched fibers in the spots is small, the difference in dyeing density from the normal spots that are not spots Is small, and good marbling tone cannot be obtained even when dyed as a woven or knitted fabric. Further, in the present invention, the number of spots is one per 1 to 900 m, which is extremely small in the longitudinal direction, and from this point, the marbling tone cannot be obtained. Further, it is disclosed that this fluff yarn is produced in a two-stage drawing, but in the described drawing method, there is a drawback that the fluctuation of the heat shrinkage is large, and when a raw yarn knitted woven fabric is produced, unevenness in texture occurs.

That is, in the prior art, a polyester multifilament yarn having a large thickness in the yarn longitudinal direction, a good frost-dyeing appearance effect and a small boiling water shrinkage variation in the yarn longitudinal direction has not been obtained.

[Object of the Invention]

The object of the present invention is to produce abnormal shrinkage unevenness in the heat treatment step of the knitting machine when the raw yarn woven or knitted fabric is untwisted or sweet twisted without special processing such as false twisting, strong twisting-heat setting. In addition, the present invention provides a polyester thick and thin yarn suitable for producing a knitted fabric having a good quality, a marbling appearance, and a good texture, and a method for producing the same.

[Structure of Invention]

1st invention of this invention WHEREIN: Each filament which comprises a polyester multifilament thread | yarn is thick and thin, and the part where 2/3 or more of all filaments is a thick part is at least 2 per 1m of thread | yarn, 4 / of all filaments. There are at least 2 parts with 5 or more details per 1 m of yarn, the fineness variation rate U% of the multifilament yarn is 3.1 to 11.8%, and the boiling water shrinkage is 4.2 to
It is a polyester thick and thin yarn having a boiling water shrinkage rate of 5% or less in the yarn longitudinal direction of 19.8%.

The polyester thick and thin yarn of the present invention has thick and thin filaments, and at least 2/3 or more of all filaments are thick portions and at least 2/5 / m of the entire filaments are fine portions. Must exist at least 2 per 1 m of yarn.

The yarn shape of the polyester thick and thin yarn of the present invention is schematically shown in FIG. Each filament has a thick hu and a fine ho in the length direction.
Is a repeated shape. Thread 1 is the portion where 2/3 or more of all filaments are thick in the cross-sectional direction of the whole thread (thick thread Hu)
In order to have a good marbling effect, it is necessary that there are 2 pieces per m and that there are at least 2 parts (thin portion Ho) where 4/5 or more of all filaments are fine (thread fine part Ho) per 1m of thread. . Figure 1 also shows the thick Hu and Ho details.

The degree of thick and thin unevenness of the polyester thick and thin yarn of the present invention in the yarn longitudinal direction is measured by a U% value measuring method described later, and the fineness variation rate is U%.
Should be in the range of 3.1 to 11.8%. U% value is 3.1%
In the dyed woven or knitted fabric which is less than the above, there is a defect that the deeply dyed part corresponding to the thick part is scattered or the frost reduction effect corresponding to the thick and thin contrast is not sufficient, and further the bulge of the woven and knitted fabric is small, so the U% value is The lower limit of 4% or more is preferable, and 5%
The above is more preferable. If the U% value exceeds 11.8%, the entire dyed woven or knitted fabric becomes deeply colored, and the defrosting effect is not sufficient. The U% value is preferably 10% or less in order to impart a good frost-decreasing effect.

The boiling water shrinkage of the thick and thin yarn according to the present invention is required to be 4.2 to 19.8%, which is an important characteristic especially for raw silk woven or knitted fabrics.
If the boiling water shrinkage is less than 4.2%, it will be difficult to obtain the swelling effect when the raw silk woven or knit is used, and if it exceeds 19.8%, the woven and knitted fabric will abnormally shrink during heat treatment such as scouring or dyeing. However, there is a defect that only a hard product can be obtained, and further, the shrinkage is too large and it is difficult to finish the woven or knitted product to a specified width. When the boiling water shrinkage ratio is 5 to 18%, the woven and knitted fabric has more bulge and is softer and has a good texture.

The fluctuation rate of boiling water shrinkage in the yarn longitudinal direction (hereinafter referred to as ws-cv%) must be 5% or less based on the measurement method described later. The greatest feature of the polyester thick and thin yarn of the present invention is that ws-cv% is small in a yarn having a fineness in the longitudinal direction of the yarn. If ws-cv% exceeds 5%, puckering-like unevenness will occur when scouring as a raw silk woven or knitted fabric, and the bulge of the woven or knitted fabric will decrease when trying to erase the puckering by stretching at the time of finishing. There is a drawback that the yarn that has been greatly contracted by is stretched and becomes uneven. ws-c
The smaller v% is, the better the better, and preferably 4% or less, more preferably 3.5% or less.

The smaller the range R of boiling water shrinkage in the longitudinal direction of the yarn, the more preferable, and the range R is preferably 4% or less and more preferably 3% or less in the measuring method described later.

The polyester forming the polyester thick yarn of the present invention is an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, or an aliphatic dicarboxylic acid such as adipic acid or sebacic acid, or A polyester synthesized from these esters and a diol compound such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopetyl glycol, and cyclohexane-1,4-dimethanol, especially 80 mol% of the constitutional unit. The polyester having ethylene terephthalate units as described above is preferable.

Further, polyalkylene glycol, pentaerythritol, methoxypolyalkylene glycol, bisphenol A, sulfoisophthalic acid, etc. may be added to or copolymerized with the above polyester component.

The cross-sectional shape of the filaments constituting the polyester thick yarn is preferably adapted especially in the case of an irregular cross section. There is no particular limitation as to the modified cross-sectional shape, but it is more preferable to adopt a T-type or Y-type to impart a silky characteristic.

When the polyester thick and thin yarn of the present invention is a raw silk woven or knitted fabric without twisting or crimping such as false twisting and special twisting such as strong twist-heat setting, ws-cv% However, the small effect can be demonstrated without any limitation.

In the present invention, the sweet twist is a twist within a range that can be knitted and woven without heat setting after twisting, and is usually 500 T / M or less.

A second invention of the present invention is to suitably produce the above-mentioned polyester yarn, which comprises a polyester multifilament undrawn yarn (1 + constant stress elongation region elongation × 0.6) times to (1 + constant stress elongation region). Elongation x 1.2) Stretching with a heating pin at a draw ratio of Tg + 20 ° C to Tg on a heating stretching roller
After heat treatment at + 60 ° C (where Tg is the glass transition temperature of the polyester unstretched yarn), the yarn is wound around a roller at room temperature at 0.03 to 0.4 g / d, and the polyester thick and thin film according to claim (1) is used. A method for producing a polyester thick and thin yarn, which comprises winding the yarn as a yarn.

It is necessary for the polyester multifilament undrawn yarn to exhibit a constant stress extension region in its tenacity extension curve in order to obtain a thick and thin yarn. When the thick and thin yarn obtained by using undrawn yarn whose constant stress elongation region is too small is used as a woven or knitted product, the contrast of light and shade becomes low when dyed, and it is difficult to obtain a marbling appearance, so 0.20 or more. Is preferable, and 0.30 or more is more preferable. When a thick and thin yarn obtained by using unstretched yarn with a too large constant stress elongation region is used as a woven or knitted fabric, the cross-sectional area ratio of thick and thin becomes too large, and when dyed, the contrast of shade becomes too strong. It is preferably below, and more preferably 0.80 or below.

It is also possible to draw continuously in the spinning process, but the constant-strength extension region is not clear in the undrawn yarn immediately after spinning, and it is difficult to form a thick or thin shape in the entire multifilament yarn even if it is drawn. Therefore, it is preferable to draw the undrawn yarn that has been wound up.

Further, the cross-sectional shape of the filaments constituting the polyester multifilament undrawn yarn can be made into a thin yarn having a small variation in boiling water shrinkage that cannot be achieved by the conventional method, particularly in the case of an irregular cross section, and is suitable for an irregular cross section. Can be adapted.

A method of drawing using the polyester multifilament undrawn yarn described above will be described in detail below with reference to the drawings. FIG. 2 is a manufacturing process diagram showing an embodiment of the present invention.

In FIG. 2, reference numeral 1 is a polyester multifilament unstretched yarn, which is (1 + constant stress elongation region elongation × 0.6) times (1 + constant stress elongation region) between the feed roller 2 and the heating stretching roller 4 via the heating pin 3. Stretching is performed at a stretch ratio of 1.2) times and set by heating on the heating stretching roller 4. Then, it is wound around the roller 5 at room temperature and wound by the winder 6.

The draw ratio is (1 + constant stress elongation zone elongation 1.2) times or less in order to obtain a U% value of the obtained thick and thin yarn of 3.1% or more, and a U% value of 4% or more and 5% or more. In order to achieve this, the draw ratio is preferably (1 + constant stress extension zone elongation × 1.1) times or less and (1 + constant stress extension zone elongation × 1.0) times or less, respectively. Also, in order to keep the U% value at 11.8% or less, it is (1 + constant stress extension zone elongation x 0.6) times or more, and the U% value is 1
To achieve 0% or less (1 + constant stress elongation zone elongation x 0.8)
It is better to double or more.

In order to obtain a good defrosting condition, it is necessary that there are specific thick and thin portions in the longitudinal direction of the yarn as described above, and it is necessary to use a heating pin in the drawing region for this purpose. The temperature of the heating pin is preferably in the range of Tg-20 ° C to Tg + 30 ° C.

When the temperature of the heating pin is less than Tg-20 ° C, the occurrence of thick and thin is not dispersed, and the thick portion is present for a long time. It is present and presents periodicity, and becomes a so-called moire tone, which is not preferable because the quality of the knitted fabric is significantly deteriorated.

On the other hand, when the temperature of the heating pin exceeds Tg + 30 ° C., the U% value of the obtained thick and thin yarn decreases, and when dyed as a woven or knitted product, the difference in shade is reduced, and it is difficult to obtain a good marbling appearance, which is not preferable. Further, when a heating plate is used in the stretching region, the thick portion and the detail are dispersed, and the thick portion and the thin portion are not formed. Therefore, it is preferable not to use the heating plate.

The temperature of the heating / drawing roller determines the boiling water shrinkage of the obtained thick yarn.
In order to obtain 4.2 to 19.8%, it is necessary to set the temperature in the range of Tg + 20 ° C to Tg + 60 ° C. In order to make the boiling water shrinkage rate 5 to 18%, it is preferable to set it to Tg + 25 ° C to Tg + 50 ° C. Note that the contact time in the heating and stretching roller is preferably 0.01 to 0.4 seconds in order to stably obtain the target boiling water shrinkage level, and 0.05 to 0.05 seconds.
~ 0.3 seconds is more preferred. The fact that the variation in boiling water shrinkage in the yarn longitudinal direction of the thick and thin yarn of the present invention is extremely small is the effect of heating in a constant length state on the stretching roller in stretching.

It is possible to wind directly from the heating draw roll with a winder, but the change in take-up tension affects the thick and thin yarns that are wound, and when a woven or knitted product is likely to cause sink marks or uneven streaks, heat drawing After heat treatment by the roller, it is necessary to supply the yarn to the roller at room temperature, wind it, and then wind it. In this case, the tension between the heating and stretching roller and the roller at room temperature is 0.03 in terms of running stability.
It is required to be g / d or more and 0.4 g / d or more from the viewpoint of preventing thick part reduction.

〔The invention's effect〕

As described above, the polyester thick thin yarn of the present invention has the yarn thick portion in which the thick portion of the filament gathers and the thin portion in which the filament yarn detail gathers alternately in the yarn longitudinal direction, Since the variation in boiling water shrinkage is extremely small, there is no puckering ring-like unevenness during scouring in the woven and knitting manufacturing process, and even if there is, it is slight, and quality, swelling, and marbling appearance due to dyeing and finishing. A good raw woven fabric can be obtained.

Therefore, the effect of the present invention can be exhibited in the case where a woven or knitted fabric is obtained by sweet twisting or non-twisting without performing crimping processing such as false twisting and special thread processing such as strong twisting-heat setting.

Further, in the manufacturing method, a simple yarn path can be used for processing with a compact device without using a special device.

Hereinafter, the present invention will be described in more detail with reference to Examples. The methods for measuring boiling water shrinkage, fineness variation, U% value, constant stress extension zone elongation, and Tg relationship are described below.

A. Boiling water shrinkage rate 1 round of 1 m 10 rounds is used as 1 case, and the original length is measured under a load of 0.1g / d, and treated in 98 ° C water for 15 minutes under a load of 0.1mg / d, 0.1g / d
d Measure the processing length under load, And this is the boiling water shrinkage of one sample. Repeat the measurement at any 50 points in the measurement sample, divide the average value by the boiling water shrinkage ratio of the sample, the difference between the maximum and minimum values in the range R of the boiling water shrinkage ratio, and divide the standard deviation by the boiling water shrinkage ratio of the sample and multiply by 100. The% displayed is ws-cv%.

B. Method for measuring U% value of fineness variation rate A commercially available Uster Eveness Tester (manufactured by Keisokuki Kogyo Co., Ltd.) is used. The measurement slot to be used is selected according to the total fineness of the yarn, the yarn speed is set to 4 m / mm, and the yarn is twisted by applying a rotation of about 1500 rpm with a twisting machine to perform the normal test. The U% value is measured at any 5 points on the measurement sample, with one measurement for 3 minutes, and is expressed as an average value.

C. Elongation of constant stress elongation zone The elongation of A on the chart shown in Fig. 3 obtained by an Instron type tensile testing machine is read, and if it is 40%, it is expressed as 0.40. The constant stress elongation zone elongation is measured at arbitrary 5 points on the measurement sample and is represented by the average value.

The D.Tg glass transition point is 69 ° C [Kolloidzeilshrift165,
40 (1959)].

Example 1 Polyethylene terephthalate unstretched yarn of 120 denier 36 filaments having an intrinsic viscosity of 0.63 in orthochlorophenol at 25 ° C. was stretched and heat-treated in the apparatus shown in FIG. The degree is 0.62, the cross-sectional shape is Y
It is a cross section. The heating pin is 80 ℃ and the drawing speed is 500m / min.
Stretched at the stretching ratio shown in, and the heating stretching roller temperature is 115 ° C
The contact time was 0.15 seconds, and the yarn was fed, wound and wound on a roller at room temperature with a tension of 0.15 g / d.

The characteristics of the obtained thick and thin yarns are as shown in Table 1. In each case, there is substantially thick and thin as the whole multifilament yarn. The numbers of thick and thin portions are shown in Table 1, respectively. There was a thick thread to show. These thick yarns were twisted at 200T / M as warp and weaving density was 127 yarns / inch, and as weft yarns, weaving density was 83 yarns / inch and 2/2 twill.
Relax scouring in water at 8 ℃, dry heat setting at 200 ℃, alkali weight loss 10%, and then dye Amacron Blue (American
a Color & Chemica Corp.) 1.0% owf and the auxiliary agent Sun Salt (Nichika Kagaku) 1.0% owf. The occurrence of puckering unevenness was slight in the scouring process of the woven fabric, and the final finished woven fabric had no unevenness and was of good quality. The texture and frost effect of the fabric corresponding to each draw ratio are also shown in Table 1. The fabric of Experiment No. 1 which is a comparative example is poor because the dark color is too strong over the entire fabric, and the fabric of Comparative Experiment 7 is comparatively poor. The woven fabric was poor because the bulging and marbling effects were too small. In addition, the thick and thin yarn of Experiment No. 6 has a small bulge and a good woven fabric with a moderate bulge was obtained, but it is not suitable for a woven or knitted fabric that emphasizes the bulge.

Example 2 In Example 1, drawing and heat treatment were carried out according to Example 1 except that the draw ratio was 1.52 times and the heating and drawing roller temperature was set to the conditions shown in Table 2, and the obtained thick and thin yarn was woven and scoured. , Dry heat setting, alkali weight loss, and dyeing were performed.

The characteristics of the obtained thick and thin yarns are as shown in Table 2. In each case, the multifilament yarn as a whole has substantially thick and thin yarns.
It was the thick thin yarn shown in. Except for Experiment No. 8, the occurrence of puckering unevenness was slight in the scouring process of the woven fabric, and the final finished woven fabric had no unevenness and had good quality and good marbling effect.

The Shibomura of Experiment No. 8 was slightly conspicuous, and some unevenness remained in the final finished fabric. The textures of the fabrics corresponding to the respective temperatures of the heating and stretching rollers are also shown in Table 2. The fabrics of Experiment No. 8 which is a comparative example are poor in a hard texture, and the fabrics of Experiment No. 14 which is a comparative example are bulged. Was too small and bad. Experiment No. 9
The fabric had a slightly hard texture, but was good. The thick yarn of Experiment No. 9 is not suitable for woven and knitted fabrics that emphasize soft texture. The woven fabric of Experiment No. 13 had a small bulge but was good. The thick yarn of Experiment No. 13 is not suitable for woven and knitted fabrics that emphasize the bulge.

Example 3 The stretching conditions of Experiment No. 11 of Example 2 were set to 880 m / min and heat-treated, and the obtained thick yarn was woven, scoured, dry-heat set, alkali-reduced and dyed. The characteristics and the fabric characteristics of the obtained thick thin yarn are shown in Table 2 as Experiment No. 15.

The texture and marbling effect were good. There was a slight puckering unevenness, but it was at a practically usable level.

Comparative Example 1 The unstretched yarn used in Example 1 was used for drawing and then heat treated with a hot plate. As the apparatus, in FIG. 2, the heating and stretching roller 4 is used without heating, a 25 cm hot plate is used between the rollers 4 and 5, and a bar guide made of alumina ceramic is used at the hot plate inlet. And both when not used. Drawing speed 500 / min, heating pin 80
C., the draw ratio was 1.52 times, and the heat treatment was carried out at the temperature and strain rate shown in Table 3.

The characteristics of the obtained thick and thin yarns are as shown in Table 3, and all have large variations in boiling water shrinkage in the yarn longitudinal direction. Weaving, scouring, dry heat setting, alkali weight loss, and dyeing were carried out according to Example 1. The characteristics of the woven fabric are also shown in Table 3. The puckering shibomura after refining is large, especially ws-cv
The larger the percentage, the more remarkable it was, and it was not possible to eliminate unevenness in any of the subsequent steps in any of the fabrics.

Comparative Example 2 In this comparative example, a polyester thick yarn in which unstretched portions are randomly distributed is compared with the thick yarn of the present invention.

The undrawn yarn used in Example 1 was preheated to 75 ° C. with a heating plate.
Stretched at 140 ° C, stretching ratio 1.50 times, stretching speed 500 m / min,
I wound up.

In the obtained thick and thin yarn, unstretched portions were randomly distributed in each filament, and neither the thick portion nor the thin portion of the present invention was present. The U% value was 4.2%, and the boiling water shrinkage ratio was 4.9%.

Weaving, scouring, dry heat setting, alkali reduction, and dyeing were carried out in accordance with Example 1, but the occurrence of unevenness in the scouring was large, and the finished fabric had a good texture, but the grade was poor and the dyeing appearance was also dyed with light and shade. I didn't get the marbling effect because I was too familiar with it.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the shape of a thick and thin yarn of the present invention, FIG. 2 is a schematic diagram of a manufacturing process preferably used in the present invention, and FIG. 3 is a strong elongation curve diagram for explaining constant stress elongation zone elongation. Is. 1: Polyester unstretched yarn 2: Feed roller 3: Heating pin 4: Heating stretching roller 5: Room temperature roller 6: Winding machine hu: Filament thick part ho: Filament detail Hu: Thread thick part Ho: Thread thin part

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Claims (2)

[Claims] 1. Each of the filaments constituting the polyester multifilament yarn is thick and thin,
There are at least 2 parts per 1 m of yarn with 3 or more thick parts, and at least 2 parts with 4/5 or more of all filaments per minute, and the fineness variation rate U% of multifilament yarn is 3.1. ~ 11.8%, boiling water shrinkage is 4.2 ~ 19.8%, the fluctuation rate of boiling water shrinkage in the longitudinal direction of the yarn is 5% or less polyester thick yarn. 2. A polyester multifilament undrawn yarn is drawn with a heating pin at a draw ratio of (1 + constant stress extension zone elongation × 0.6) times to (1 + constant stress extension zone elongation × 1.2) times and heated. After heat treatment at Tg + 20 ° C. to Tg + 60 ° C. (where Tg is the glass transition temperature of the polyester unstretched yarn) on a stretching roller, the yarn is wound at 0.03 to 0.4 g / d on a roller at room temperature, The method for producing a polyester thick and thin yarn, characterized in that the polyester thick and thin yarn is wound up.