JP2541322B2 - Manufacturing method of polyester shrinkage difference mixed yarn - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyester shrinkage differential mixed yarn. More specifically, the present invention relates to a method for producing a polyester shrinkage-differential mixed yarn capable of maintaining a soft texture even after high-temperature dry heat treatment after knitting and weaving and relaxing heat treatment.

[Prior Art] Conventionally, polyester shrinkage differential blended yarns have been used for high-quality silky woven or knit applications with a soft texture and good bulkiness and drapeability, and various applied products have been popular in the market.

The polyester shrinkage-differential mixed yarn is a yarn in which two or more types of polyester yarns having different thermal shrinkages are mixed. It is also known that in order to impart a difference in shrinkage, a difference in heat treatment between yarns, a difference in the degree of polymerization of polyester, and the like, as well as a difference in the copolymerization rate.

Examples of polyester shrinkage difference mixed filament yarns having different copolymerization ratios include JP-A-55-45873. Such a mixed fiber yarn is knitted and knitted, and then heat-treated in a relaxing process such as refining, whereby a latent heat shrinkage difference appears between the yarns, and a sufficient bulkiness is obtained even under the constraint of the structure of the woven or knitted fabric. The silky knitted fabric exhibiting softness and soft texture can be obtained. However, this woven or knitted fabric is exposed to high-temperature heat treatment until it becomes a final product after undergoing steps such as alkali treatment, dyeing, intermediate setting, and printing.
The yarns forming the woven or knitted fabric further shrink. Therefore, the good texture after the initial relaxation heat treatment cannot be maintained, resulting in a woven or knitted fabric having a hard and rough texture.

On the other hand, in JP-A-64-20320, an attempt is made to obtain a polyester differential shrinkage mixed fiber by a high speed spinning method.
The publication discusses the relationship between the copolymerization ratio of the high shrinkage component polymer and the spinning speed. However, due to lack of consideration for heat drawing and heat treatment, only those having low heat shrinkage stress can be obtained. Therefore, although it is possible to obtain a soft texture, there is a drawback that the woven or knitted fabric is insufficient in expressing the bulk under restraint and lacks a bulging feeling.

[Problems to be Solved by the Invention] Recently, high-speed spinning at a spinning speed of 4000 m / min or more is becoming widespread as a production process of melt spinning such as polyester. This is because not only the process itself has a large cost reduction effect, but the fiber obtained by this is compared with the fiber obtained by the two-step method of conventional spinning and drawing,
This is because it exhibits excellent properties such as soft texture and dyeability.

Woven and knitted fabrics made from high speed spun fibers are soft and have a good texture. This is because the orientation of the amorphous part molecular chain in the fiber becomes low and the substrate itself becomes soft due to the process of forming a special structure. Therefore, although it is considered that the process may be suitable for obtaining a shrinkage-differential mixed yarn having a soft and swelling feeling, it has been proved that this is not always the case.

This is because the fibers obtained by high-speed spinning differ from the fibers obtained by the conventional two-step method in the shrinkage behavior. The inventors of the present invention have paid attention to this point, and have conducted intensive studies to arrive at the present invention.

An object of the present invention is to provide a polyester shrinkage-differential mixed yarn without the above-mentioned defects, that is, a polyester shrinkage-differential mixed yarn capable of exhibiting sufficient bulkiness by knitting and weaving, relaxing heat treatment, and maintaining a soft texture even under high temperature dry heat treatment. It provides a manufacturing method of yarn.

[Means for Solving the Problem] That is, the above-mentioned object of the present invention is to produce a polyester shrinkage-differential mixed yarn in which the difference in the copolymerization rate between the polyester having the highest copolymerization rate and the polyester having the lowest copolymerization rate is By melt-spinning two or more polyesters of 10 mol% or more, cooling and solidifying each yarn once, and then subjecting each yarn to a drawing heat treatment by passing through a common heating zone, and then taking it back. , The heat shrinkage stress of the mixed fiber is 0.
3 g / d or more, the peak temperature of heat shrinkage stress is 105 ° C or more, and the difference ΔS = SH ₂ −SH ₁ between the dry heat shrinkage SH ₂ after boiling water treatment and the boiling water shrinkage SH ₁ is 10% or less. It can be achieved by a method for producing a polyester shrinkage differential mixed yarn.

The polyester shrinkage difference mixed fiber obtained by the present invention has two major characteristics.

That is, first, the shrinkage-differential mixed fiber obtained by the method of the present invention exhibits sufficient bulkiness even under the restraining force of the woven or knitted fabric structure. This property can be characterized by the bulkiness M of the mixed fiber, which is determined by the measuring method described later, and M
Corresponds to 25 cc / g or more, preferably 30 cc / g or more.

The reason why this characteristic is obtained is that polyesters having different copolymerization rates of 10 mol% or more are melt-spun, the yarns are once cooled and solidified, and then the yarns are drawn and heat treated by passing through a common heating zone. This is because A structure for drawing out a high heat shrinkage stress of 0.3 g / d or more is formed by passing through this zone and subjecting it to stretching heat treatment. This property is
This is similar to the property of a conventional yarn that is drawn after low-speed spinning. As disclosed in JP-A-64-20320, the yarn obtained in the high-speed spinning process without consideration for the stretching heat treatment in the heating zone has a high degree of crystallinity and a low degree of amorphous orientation.
The heat shrinkage stress is 0.25 g / d or less, and it does not have sufficient capacity to express bulk under restraining force. On the other hand, in the present invention, since the heat shrinkage stress is high, sufficient bulkiness can be exhibited even under the restraining force of the woven or knitted fabric structure. Moreover, it is possible to maintain the soft texture unique to high-speed spinning.

The second feature of the polyester shrinkage differential mixed yarn of the present invention is
The soft texture can be maintained even with high-temperature heat treatment after the appearance of bulk. The reason is that the first bulk development treatment after weaving and knitting releases all the heat shrinkage stress, resulting in an extremely stable fiber structure, and further shrinkage hardly occurs in the subsequent heat treatment. This property is
Difference ΔS = SH ₂ −S between dry heat shrinkage SH _{2 of the} mixed fiber after boiling water treatment and boiling water shrinkage SH ₁ obtained by the measuring method described later.
It is characterized by H ₁ and corresponds to ΔS of 10% or less, preferably 5% or less. Although this property is similar to that of a yarn obtained by high-speed spinning without a heating zone, it is different from the conventional shrinkage-differentiated mixed yarn that is drawn after low-speed spinning winding, as described in JP-A-55-45873. Totally different. In the shrinkage difference mixed yarn obtained in the conventional yarn making process, the yarn is further shrunk by the high temperature heat treatment after the bulk expression treatment after the knitting and weaving, and the final product has a rough and hard texture, and the appearance of the woven fabric is a sink mark defect. Will occur. What shows such a special heat shrinkage behavior is
It is believed that the two or more yarns of the present invention pass through a common heating zone. Stretching in the heating zone is extremely complicated because the fiber orientation of the yarn entering the heating zone, the spinning tension, the ease of stretching based on the polymer matrix and the temperature raising process of the yarn in the heating zone influence each other. It is a phenomenon.

However, conversely, the advantage of passing two or more types of yarns through the common heating zone is that the stretching of each yarn can be naturally controlled so as to be optimal including the draw ratio. In the present invention, by passing two kinds of yarns through a common heating zone, a yarn consisting of each component having a different copolymerization rate can be optimally stretched, so that the special heat shrinkage as described above is performed. It is considered to behave.

As described above, it is only the mixed filament yarn obtained by the present invention that bulk develops under the restraining force of the woven or knitted fabric structure and can maintain its soft texture by the high temperature treatment after the bulk development. This is because of the special fiber structure of the fiber obtained by the combination of the polyester specified in 1. and the yarn making method.

In the present invention, the difference in the copolymerization rate between the polyester having the highest copolymerization rate and the polyester having the lowest copolymerization rate needs to be 10 mol% or more. Here, the copolymerization rate P (mol%)
Is the sum of the mole fraction Pa (mol%) of the copolymerized acid component to all the acid components of the copolymerized polyester and the mole fraction Pb (mol%) of the copolymerized glycol component to all the glycol components of the copolymerized polyester, That is, it is a value represented by P = Pa + Pb.

In these polyesters, the copolymerization rate is 10 mol%
If there is no difference, the difference in heat shrinkage is small and sufficient bulkiness cannot be exhibited. Polyester having a high copolymerization rate is a component of the yarn on the high shrinkage side, and it is preferable that the copolymerization rate be 30 mol% or less in order to secure a soft texture, particularly 25
It is more preferably not more than mol%. The polyester having a low copolymerization rate is a component of the yarn on the low shrinkage side of the mixed fiber of the present invention, and may be a polyester containing substantially no copolymerization component.

As the copolymerization component in the present invention, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, aliphatic diols, alicyclic diols, aromatic diols or diols obtained by adding ethylene oxide or the like to these can be used. , Specifically isophthalic acid, naphthalene-2,6
-Dicarboxylic acid, adipic acid, sebacic acid, 1,4-butanediol, diethylene glycol, trimethylene glycol, polyethylene glycol having a molecular weight of about 600 to 6000, cyclohexanediol, ethylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol sulfone, etc. It can be preferably used.
Since the shrinkage behavior depends on the copolymerization component,
It is necessary to set the copolymerization ratio so that is within the range of the present invention.

It is preferable to use an aromatic diol as a monomer which has particularly good thermal stability and tends to have a high boiling water shrinkage SH _1. For example, an ethylene oxide adduct of isophthalic acid and bisphenol A can be used as a monomer of the following formula. It is more preferable to copolymerize at a ratio.

10.0 ≤ Fa + Fb ≤ 25.0 1.0 ≤ Fb ≤ 4.8 (Fa is the mole fraction of isophthalic acid to the total acid component of the copolyester (%), Fb is the mole fraction of bisphenol A ethylene oxide adduct to the total glycol component of the copolyester. % (%)) In order to secure a soft texture, it is preferable that Fa + Fb be 25 mol% or less. Further, in order to sufficiently develop the bulk, which is a merit of copolymerizing isophthalic acid and an ethylene oxide adduct of bisphenol A, and to set a preferable bulk height range to 30 cc / g or more, Fb is set to 1.0 mol% or more. preferable. On the contrary, in order to reduce the shrinkage during high temperature heat treatment and maintain the soft texture in the final product,
Fb is preferably 4.8 mol% or less.

As the polyester of the present invention, polyethylene terephthalate containing ethylene terephthalate as a basic unit can be preferably used. The intrinsic viscosity of polyester is 0.45 to 0.75 in an orthochlorophenol 25 ° C solution.
Is preferable, and the range of 0.55 to 0.65 is more preferable.
Further, if slack occurs in the wound package, it becomes difficult to pull out the yarn or pass through the process in a subsequent process, so in order to prevent this, it is preferable to change the intrinsic viscosity between polyesters having different copolymerization rates. It Further, it is also preferable to increase the difference in shrinkage rate by combining the copolymerization rate and the intrinsic viscosity such as increasing the intrinsic viscosity of the polyester having a high copolymerization rate.

In the present invention, the above-mentioned two or more polyesters are discharged from separate discharge holes to be cooled and solidified, passed through a common heating zone, stretched and heat-treated and wound. The shape of the spinneret hole may be circular, Y, T, or any other known shape. Two or more components of polyester may be discharged from one spinneret, or may be discharged from two or more spinnerets. The state of dispersion of high and low shrinkage yarns of mixed yarn, so-called "kore",
A method in which two or more components of polyester are discharged by one spinneret is preferable, and it is more preferable that the discharge hole groups of each yarn are arranged in an annular shape or alternately, which is preferably used in the present invention.

The polyester discharged from the spinneret is cooled and solidified by cooling air. The cooling is performed until the temperature at which the polyester yarn solidifies, that is, the glass transition temperature or less, so that the subsequent drawing heat treatment can be stably performed.

The polyester yarn once cooled and solidified is introduced into a heating zone and subjected to a drawing heat treatment. In the heating zone, it is preferable that the yarn is not brought into contact with anything other than the yarn path regulating portion at the inlet or the outlet so that the yarn can be freely stretched. A heating cylinder is preferably used as the heating zone. This heating cylinder
It is preferable to use one that is heated from the surroundings, one that is heated and introduced into dry hot air, one that is filled with saturated steam, or a combination thereof.

In the heating zone, it is necessary that the yarn passing through is subjected to drawing heat treatment. As a result of the stretching heat treatment, the heat shrinkage stress is 0.3 g / d or more, and the heat shrinkage stress peak temperature is 105
A mixed yarn having a temperature of ℃ or higher can be obtained. Stretching heat treatment refers to stretching and subsequent heat treatment. In order for the drawing to occur, it is necessary that sufficient tension necessary for drawing be applied to the yarn and that sufficient heat be supplied from the heating zone.

Here, the tension is (actual tension of the yarn at the inlet of the heating zone) / (winding yarn denier), such as the single yarn denier of the winding yarn, the take-up speed, and the distance from the spinneret to the heating zone. It changes with. The tension required for stretching is usually 0.3 g / d
That is all. When the drawing tension is less than 0.3 g / d, the heat shrinkage stress of the yarn does not reach 0.3 g / d, so that the bulk does not appear under the binding force of the woven or knitted fabric structure.

Further, the heating zone temperature necessary for drawing and heat treating the yarn passing through the heating zone is preferably 105 ° C. or higher, 110
C. or higher is more preferable. If the heating zone temperature is lower than 105 ° C., even if stretching occurs, sufficient heat treatment is not performed, and the boiling water shrinkage rate exceeds 60%, which is extremely high, and only a rough woven or knitted fabric can be obtained.

The temperature of the heating zone is a large factor that influences the heat shrinkage rate of the mixed fiber, and in order to obtain a bulk with a sufficient swelling feeling, heat treatment corresponding to a peak temperature of heat shrinkage stress of 140 ° C or less is performed. It is preferable that the heat treatment corresponds to a peak temperature of heat shrinkage stress of 130 ° C. or lower. Peak temperature of the heat shrinkage stress is 140 ℃ or less and 130
Approximate temperatures in the heating zone below ℃ are
It is below 150 ℃ and below 140 ℃.

The distance from the spinneret to the heating zone inlet is preferably 0.5 to 4.0 m in order to provide sufficient cooling under the spinneret, sufficient workability and sufficient tension generated by air resistance.
1.0 to 3.0 m is more preferable. The length of the heating zone is preferably 0.5 to 3.0 m, more preferably 1.0 to 2.0 m from the viewpoint of stable stretching heat treatment and energy saving. The take-up speed is 4000-7000 m / in terms of the mechanical properties of the obtained yarn and the surface of the spun yarn.
Min is preferable, and 5000 to 6000 m / min is more preferable.

In the present invention, two or more types of polyester yarns are passed through the common heating zone as described above. However, in order to improve the dispersed state of the yarns of the mixed fiber, so-called "coarseness", It is suitable that each yarn passes through a common heating zone. Even if each yarn is passed through a separate heating zone and mixed until it is wound up to try to increase the dispersibility by air entanglement treatment, the "kore" does not become good, and conversely fluff occurs during air entanglement treatment. Will increase.

In the polyester of the present invention, in order to reduce frictional resistance with a yarn guide or the like in a yarn making process or a weaving / weaving process, or to impart a special hue such as mild luster and dull, titanium oxide, carbon dioxide It is preferable to add 0.015 to 5.0% by weight of fine particles such as calcium, kaolin, metakaolin and silica. In addition, in order to add other functionality, antistatic agents, flame retardants, light stabilizers, moisture absorbents, coloring agents, etc.
If necessary, it can be added within the range of 01 to 5.0% by weight.

It is obtained by making the single yarn denier after winding a yarn made of polyester with a high copolymerization rate 1.2 to 5.0 times larger than the single yarn denier after winding a yarn made of a polyester with a low copolymerization rate. Since the woven and knitted fabric has good elasticity and tension, it is preferably used in the present invention. Further, in this case, by setting the single yarn denier of the yarn having a small single yarn denier to 1.0 denier or less, a softer texture can be imparted to the woven or knitted fabric, which is suitable for the present invention.

In the mixed yarn of the present invention, each yarn or one of the yarns can be a composite fiber as long as its characteristics are not impaired. Such a composite fiber may contain an easily-eluting component, an antistatic component, and a conductive component in addition to the polyester having a different copolymerization rate used in the present invention.

[Examples] The present invention will be described more specifically by the following examples.

First, the methods for measuring heat shrinkage stress, boiling water shrinkage, dry heat shrinkage after boiling water treatment, and bulk height in the present invention will be described below.

A. Heat shrinkage stress and peak temperature of heat shrinkage stress Using a Kanebo Engineering thermal stress measuring instrument KE-2 type, a 20 cm sample (mixed yarn) is looped to 10 cm,
After adjusting by applying an initial load of denier x 1/15 of the sample (mixed yarn) to be measured, the temperature is raised at a heating rate of 150 ° C / min to obtain a heat shrinkage stress curve. From this curve, the stress at the peak position (g /
Read d) and temperature (° C). The recorder used was Yokogawa Electric's XY recorder, type 3083.

B. Shrinkage rate of boiling water One sample is a skein machine with a circumference of 1 m and 10 turns, and the original length L ₁ is calculated under a load of 0.1 g / d. Next, after processing for 15 minutes in boiling water under no load, the length after processing at 0.1 g / d
Seeking L _2, (the average value of the measurement number 5 times) for calculating a boiling water shrinkage SH ₁ (%) from the following equation.

SH ₁ = {(L ₁ −L ₂ ) / L ₁ } × 100 C. Dry heat shrinkage rate after boiling water treatment After the above boiling water treatment, the sample was air dried and then dried under a load of 2 mg / d. ℃ in the oven for 5 minutes, then 0.1
The length L ₃ after the treatment under a load of g / d is obtained, and the dry heat shrinkage rate SH ₂ (%) after the treatment with boiling water is calculated by the following formula (an average value of 5 measurements is taken).

SH ₂ = {(L ₁ −L ₃ ) / L ₁ } × 100% D. Bulk altitude FIG. 1 is a perspective view of an apparatus for measuring the bulk altitude M,
2 (A), (B) and (C) are sketches for explaining the measuring method by this device.

Two notches 2 are provided on the upper surface of the sample table 1, the outer edge interval 3 is set to 6 mm, a flexible film 4 having a width of 25 mm is laid over the notches 2, and a metal fitting 5 with a pointer and a load 6 are attached to the lower end thereof. Join. The pointer of the metal fitting 5 is set so as to indicate the 0th position of the scale 7 when the sample is not attached.

The sample is a 480-meter yarn with a circumference of 1 m
Prepare a cassette so that it will be 00 denier (for example, for a yarn with a display fineness of 30 denier, 30 x 80 x 2 = 4800, 4800
0 ÷ 4800 = 10 for 10 cassettes, and for a yarn with a display fineness of 75 de Beer, 75 x 80 x 2 = 12000, 48000/12000 = 4 for 4 cassettes). The casks are subjected to the same heat treatment as the dry heat shrinkage measurement after the boiling water treatment of the above item C, and the casks are aligned. Next, the aligned cassettes are folded in four as shown in FIG. 2 (A) to form a sample 8, and as shown in the front view of FIG. 2 (B) and the cross-sectional view of (C), The sample 8 is gently inserted between the film tape 4 and the sample table 1. The load 6 is set to 50 g in total with the metal fitting 5 with a pointer, and the value L (cm) indicated by the pointer is read.

 The bulk altitude M is calculated from the following equation.

M (cc / g) = V / W V = (L ² /π)×2.5 W = D × {100 / (100−SH ₂ )} × P × (0.025 / 9000) (where V is in the tape Volume (cc), W is the yarn weight (g) in the tape, D is the fineness (denier) of the sample yarn before heat treatment, P is the number of parallel yarns in the tape, and SH ₂ is the above C term. Measured dry heat shrinkage.) Example 1 After esterification reaction using terephthalic acid / ethylene glycol and isophthalic acid / ethylene glycol slurry, ethylene glycol solution of bisphenol A · 2 ethylene oxide adduct was added. Polymerization is carried out by an ordinary method, and the molar fraction Fa of isophthalic acid to the total acid component of the copolyester is 11.0%, and bisphenol A to the total glycol component of the copolyester
2 Ethylene oxide adduct molar fraction Fb 4.0%, 25 ℃
Copolymerized polyester chips with an intrinsic viscosity of 0.67 in orthochlorophenol were obtained.

In addition, chips of polyethylene terephthalate having an intrinsic viscosity of 0.65 in orthochlorophenol at 25 ° C. which were not copolymerized were obtained.

 The difference in the copolymerization rate is 15.0 mol%.

Further, calcium carbonate particles were added to the above-mentioned copolymerized polyester, and particles derived from the catalyst were generated in polyethylene terephthalate which was not copolymerized, and the passability in the yarn making process and the higher step was improved.

Polyethylene terephthalate not copolymerized from 12 Y holes located at PCD 70 mm of the spinneret, and copolyester from 12 Y holes located at PCD 40 mm were spun at the same discharge amount at a spinning temperature of 290 ° C. After passing through the heat retaining area of 20 cm below the spinneret, cooling with a uniflow chimney with a wind speed of 20 m / min, an air temperature of 30 ° C and a length of 50 cm, a length of 1.5 m with an inlet at a distance of 1.5 m from the spinneret, an inner diameter of 30 mm, Stretching heat treatment is performed with a heating cylinder with an inner wall temperature of 130 ° C, and an oil agent and entanglement are sequentially applied,
Wind speed 5200m / min, 1st, 2nd take-up roll, tension 0.25g /
At d, a 50 denier 24 filament mixed yarn was wound up.
At this time, the tension at the inlet of the heating zone was 0.46 g / d.

 The obtained yarn was designated as No. 1 and its yarn properties are shown in Table 1.

This yarn is woven vertically and horizontally into a habutae, relaxed and scoured for 5 minutes in boiling water, dried at 200 ° C for 5 minutes, dried at 130 ° C, and dyed at 130 ° C. After the printing process, 180 ° C, It was heat set for 30 minutes. The texture and appearance of the obtained woven fabric are shown in Table 1.

As is clear from Table 1, No. 1 has a heat shrinkage stress of 0.3 g / d or more and a heat shrinkage stress peak temperature required in the present invention.
Satisfies all the characteristics of 105 ° C or higher, ΔS of 10% or lower, and bulk height of 25 cc / g or higher. Therefore, a good woven texture,
The appearance is shown.

Comparative Example 1 Cooling was carried out in the same manner as in Example 1, and without drawing heat treatment in the heating zone, after oiling at 2.2 m below the spinneret, focusing and entanglement were applied, and each roll was taken at 5600 m / min. No. 2 is a 50-denier 24-filament yarn wound with a tension of 0.25 g / d.

Spin, cool and wind at 1800 m / min as in Example 1,
The wound yarn is drawn 2.7 times at 87 ℃, heat treated with a heating roll at 125 ℃ and wound into 50 denier 24 filament yarn.
No.3

 Table 1 shows the properties of the mixed yarns of Nos. 2 and 3.

A woven fabric similar to that of Example 1 was obtained using the obtained mixed fiber. The texture and appearance of the obtained woven fabric are shown in Table 1.

As is clear from Table 1, No. 2 does not undergo the stretching heat treatment in the heating zone, so the heat shrinkage stress is low, the bulk development in the fabric is not sufficient, and the fabric has a flat texture. .

No. 3 is also different from the present invention in the manufacturing method of the mixed yarn, so Δ
S, i.e., SH ₂ -SH ₁ is It is beyond the 10, it is assumed texture of the fabric coarse hardness, appearance sink-like defect occurs constituent yarn, it has become a coarse.

Example 2 Isophthalic Acid Molar Fraction of Copolymerized Polyester and Bisphenol A.2 Ethylene Oxide Adduct Molar Fraction
A polyester shrinkage-differential mixed yarn was obtained in the same manner as in Example 1 except that Fb was changed. Table 2 shows Fa and Fb, their yarn characteristics, and the texture and appearance of the woven fabric obtained in the same manner as in Example 1.

As is clear from Table 2, No. 7 is a comparative example, in which the difference in the copolymerization rate is less than 10 mol%, the bulkiness of the woven fabric is small, and the bulge is not felt.

In Nos. 4 and 6, the Fb is not within the range of 1.0 to 4.8 mol%, so that the feeling of swelling in the woven fabric feel is slightly poor or it is slightly coarse and hard, but it is the conventional yarn of Comparative Example 1.
It is better than Nos. 2 and 3 and is within the scope of the present invention. No. 8 has a difference in copolymerization rate of more than 25 mol%, so that the shrinkage rate is high, the texture is slightly rough and the dyeing spots are slightly seen, but the degree is small and the object of the present invention is achieved. .

Example 3 Mixed filament yarn Nos. 9 to 11 having 50 denier 24 filaments were obtained in the same manner as in Example 1 except that the inner wall temperature T of the heating cylinder was changed. The yarn properties are shown in Table 3.

A woven fabric similar to that of Example 1 was obtained using the obtained mixed fiber. Table 3 shows the texture and appearance of the obtained woven fabric.

As is clear from Table 3, the heating cylinder temperature of the comparative example is
No. 9 at 100 ° C was a yarn that did not undergo heat treatment inside the heating cylinder, had a very high shrinkage rate, and could not be used at all.

The No. 10 and No. 11 levels obtained by the present invention show almost good woven texture and appearance. However, No. 11, which has a heat shrinkage stress peak temperature of over 150 ° C, has a slightly low shrinkage factor and is slightly poor in the feeling of swelling of the fabric texture.

[Effects of the Invention] The polyester shrinkage-differential mixed yarn obtained in the present invention exhibits sufficient bulkiness under the restraining force in the woven or knitted fabric, and can maintain its soft texture by the high temperature treatment after the bulk development. Therefore, the final product can be made into a silky woven or knitted fabric, which is extremely soft and has a feeling of swelling as compared with the conventional product. Further, the polyester shrinkage-differential mixed yarn obtained in the present invention has each component having different shrinkage ratio well dispersed with each other, and the yarn of the high shrinkage component is not pulled, so that the appearance of the final product is also very good. Will be things. Further, according to the production method of the present invention, it is possible to obtain a polyester shrinkage-differential mixed yarn at a lower cost than that of the conventional production method and with good spinnability.

[Brief description of drawings]

FIG. 1 is a perspective view of an apparatus for measuring the bulk altitude M, and FIGS. 2 (A), (B) and (C) are sketches for explaining the measuring method by this apparatus.

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Claims (1)

(57) [Claims] 1. A method for producing a polyester shrinkage difference mixed yarn, wherein two or more kinds of polyesters each having a difference in copolymerization rate of 10 mol% or more between the polyester having the highest copolymerization rate and the polyester having the lowest copolymerization rate are respectively used. After melt-spinning, each yarn is once cooled and solidified, and then each yarn is passed through a common heating zone to be drawn and heat treated, and then taken off to obtain a heat shrinkage stress of 0.3 g / d or more, the peak temperature of heat shrinkage stress is 105 ° C or more, and the difference between dry heat shrinkage SH ₂ and boiling water shrinkage SH ₁ after boiling water treatment is ΔS = SH ₂ −SH ₁ is 10%.
A method for producing a polyester shrinkage-differential mixed yarn, characterized in that: