JPH04352836A - Production of latently bulky polyester conjugate yarn for woven and knit fabric - Google Patents

Abstract

PURPOSE:To obtain conjugate yarn of polyester providing cloth having soft and elegant dry touch and proper tension and liveliness without problems of passage of processes. CONSTITUTION:Polyester multifilament having self elongation at high temperature is combined with polyester multifilament having shrinkage to produce latently bulky conjugate yarn of polyester for woven and knit fabric.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention provides a method for producing a polyester composite yarn for silk-like woven and knitted fabrics that is soft and flexible, has a dry touch, and has appropriate elasticity, elasticity, and drape properties. Regarding. [0002] Polyester multifilament has hitherto been used in a variety of applications, including clothing and industrial materials, taking advantage of its excellent properties. Silk-like texture is one of the targets for clothing applications, and various companies are investigating it, and in some fields, it has been found that silk-like texture has surpassed that of silk. For example, composite yarns consisting of a plurality of multifilaments with different heat shrinkage properties are widely used because they exhibit excellent properties and textures such as fullness, bulk, and warm feel. However, if all the multifilaments that make up the yarn shrink due to heat, due to the constraining force of the texture of the knitted fabric, it is not possible to ensure a sufficient difference in the shrinkage rate of the yarn, and the knitted fabric becomes stiff due to the shrinkage of the yarn. Therefore, countermeasures have been taken, such as reducing the basis weight to allow for shrinkage, and increasing the alkali weight loss rate to maintain the texture. However, filaments with a high heat shrinkage rate generally harden when heat treated, making it impossible to obtain a filament that is fully satisfactory in terms of feel. On the other hand, mixed yarns of polyester filaments that are elongated and filaments that are shrunk by heat treatment are also known, such as those disclosed in JP-A-55-62240, JP-A-56-112537, and JP-A-60-2.
There are publications such as Publication No. 8515. Although these yarns had a much softer and more flexible texture than the above-mentioned shrink yarns, the loops made of elongated and protruding filaments gave a slimy feel, and heat treatment caused large yarn length differences. As a result, the threads separate, causing problems in handling in subsequent processes. [0003] The present invention solves the above-mentioned conventional drawbacks of polyester filaments, and has softness, flexibility, elegant dry touch, appropriate elasticity, waist, and drapability. The object of the present invention is to provide a novel method for producing a polyester composite yarn that does not have any problems in passing through subsequent processes. Means for Solving the Problems The present invention has the following configuration in order to solve the above problems. That is, the elongation at break of the multifilament drawn yarn is 30 to 45%, Δn0.
10 to 0.14 polyester multifilament using a non-contact heater to form formulas (1) and (2) of formula [A] below.
Heater temperature T (°C) that simultaneously satisfies the formula and 20~
Polyester multifilament A satisfying the following formula [B] and polyester multifilament B were subjected to relaxing heat treatment at an overfeed rate of 60%, and A/B = 20 to 80%/80 to 20% (denier The degree of entanglement is 20 to 100 pieces/m so that
This is a method for producing a latent bulky polyester composite yarn for woven or knitted fabrics, which is characterized by an interlacing treatment. [A]75log {(D×Vy)1/2 /HL}+
4.7(Vy)1/2 ≧T≧25log {(D×V
y)1/2/HL}+4.7(Vy)1/2...
(1) T≦Tm-10...(2) D: Denier after relaxation V: Relaxation trading roller speed (m/min) HL:
Relaxed non-contact heater length (m) Tm: Melting point (°C) Tg: Secondary transition temperature (°C) [B] SHW (A) ≧0%, SHD (A) ≦0% SHW
(B)≧0% SHD(B)-SHD(A)≧5% DE(A)≧50% SHW: Hot water (100°C) shrinkage rate (%) SHD: Dry heat (
(160°C) Shrinkage rate (%) DE: Breaking elongation (%) [0005] The method for producing the polyester composite yarn of the present invention will be explained. A schematic side view of the apparatus for producing polyester composite yarn of the present invention is illustrated in FIG. To produce polyester multifilament A with excellent spontaneous elongation, first, an undrawn yarn spun at a spinning speed of 1500 to 4000 m/min is stretched at a stretching temperature of Tg to Tg + 20°C and a breaking elongation of 30 to 45%, Δ It may be stretched within the range of n0.10 to 0.14. If the spinning speed is less than 1500 m to min, the physical properties after stretching will be unstable and thickness unevenness will become large, which is not preferable. Moreover, if it exceeds 4000 m/min, the heat shrinkage rate after stretching will be low and the spontaneous elongation will be low, and the texture of the woven or knitted fabric will not be the desired one. Preferably 2000-4
000m/min. The stretching temperature is preferably higher than Tg for stretching stability, and at temperatures higher than Tg+20°C, crystallization progresses and spontaneous extensibility decreases. Further, the stretching temperature is important for the expression of spontaneous elongation, but in terms of operability such as thread breakage during stretching, it is necessary to set the elongation at break to 30% or more. If the elongation at break is 45% or more, thread unevenness may occur, which is not preferable. In total, it is necessary to keep Δn in the range of 0.10 to 0.14, and outside this range, the stability of spontaneous elongation due to relaxing heat treatment is lacking. Next, relaxing heat treatment using a non-contact heater that gives spontaneous elongation is performed at a heater temperature T (
℃) and an overfeed rate of 20 to 60%. 75log {(D×Vy)1/2/HL}+4.7
(Vy)1/2 ≧T≧25log {(D×Vy)1
/2 /HL}+4.7(Vy)1/2...(1) T≦Tm-10...(2) D: Denier after relaxation V: Relaxed trading roller speed (m/min) HL:
Relax non-contact heater length (m) Tm: Melting point (°C) Tg: Secondary transition temperature (°C) The inventors discovered the relationship expressed by equation (1). (1) If the value is higher than the range of formula, the spontaneous extensibility will decrease due to the progress of crystallization,
Moreover, if it is low, the expression of spontaneous elongation will be weak. Also (1)
It is necessary to satisfy formula and formula (2) at the same time, but if the heater temperature is set to (Tm-10)°C or higher, the multifilament will melt due to the heat of the heater when the doffing is stopped, and the multifilament will be restarted. The starting performance is reduced and it cannot be used industrially. Furthermore, relax trading roller speed V
Preferably, y is 10 to 1500 m/min, and the relax non-contact type heater length HL is 0.1 to 2 m. [0006] The overfeed rate is 20 to 60 in order to express spontaneous elongation and stabilize the operability of relaxing heat treatment.
% is good. It should be noted that if the heater is a contact type heater, the yarn tension at the inlet of the heater will be insufficient due to the multifilament running resistance, resulting in roller wrapping and yarn breakage, so it is necessary to use a non-contact type heater. This polyester multifilament A is intertwined with a polyester multifilament different from the polyester multifilament A so that the denier ratio becomes 20 to 80%/80 to 20%, and the degree of entanglement is 20 to 100 co/m. Here, different polyester multifilaments include, for example, SHW. S
Refers to those that have at least one different heat shrinkage characteristic such as HD. [0007] Through dyeing and setting treatment, due to the difference in yarn length,
In order to obtain a woven or knitted fabric with good swelling, tension, elasticity, and bulkiness, the polyester multifilament B component should have a boiling water shrinkage rate of 5% or more and a 160° C. dry heat shrinkage rate of 7% or more. If both are lower than this, a sufficient yarn length difference will not be obtained and a woven or knitted fabric with a good texture will not be obtained. Note that the boiling water shrinkage rate is preferably 5 to 60%, and the 160°C dry heat shrinkage rate is preferably 7 to 80%. Of course, the polyester multifilament may be a so-called thick-and-thin yarn or a spontaneously extensible yarn, but in the case of the former, the shrinkage rate in hot water is 5 to 30%, and in the case of the latter, the shrinkage rate in dry heat at 160°C is 0%. It is sufficient that the difference in elongation from multifilament A is at least 5%. It is also important to mix the material so that the denier ratio is 20 to 80%; if the spontaneously extensible polyester multifilament is less than 20%, it will swell and lack bulkiness, and if it exceeds 80%, the tension will be poor. , it becomes something that has no waist. The degree of entanglement is 20 to 100 to obtain ease of handling in twisting, warping, and weaving, and to obtain a uniform appearance in woven or knitted fabrics.
It is necessary to set it to m. If it is less than 20 pieces/m, polyester multifilament A and polyester multifilament B are likely to separate, resulting in poor handling in the next step. If it exceeds 100 pieces/m, a uniform appearance cannot be obtained in woven or knitted fabrics. Polyester multifilament A with the above structure provides excellent handling, spontaneous elongation, and productivity.
A composite yarn of polyester multifilament B and polyester multifilament B can be obtained. Next, the composite yarn obtained by the manufacturing method of the present invention will be described. FIG. 2 is a model diagram after the polyester composite yarn of the present invention is heat-treated to develop a yarn length difference. In FIG. 2, A is a multifilament that mainly constitutes the sheath portion, and has been substantially elongated by high-temperature heat treatment (multifilament after spontaneous elongation). B is a multifilament constituting the core, which is a multifilament that has been shrunk by heat treatment (multifilament after heat shrinkage). First, the heat shrinkage characteristics of the constituent multifilament, which is the most important requirement in the present invention, will be described. The multifilament A constituting the polyester composite yarn of the present invention has a small shrinkage rate difference with the multifilament B during normal sizing and other processes, and shows substantial shrinkage behavior. For this reason, even when creating the same yarn length difference in the fabric, even if sizing is done at the yarn stage, the yarn length difference (bulges, loops, etc.) does not appear much, even compared to ordinary different shrinkage blended yarns that are all heat-shrinkable. During weaving, handling and weaving properties are much better. In other words, the yarn length difference (
Naturally, when loops develop, the loops rub against each other during beaming and weaving, causing them to get caught in guides, combs, etc., or openings become poor, significantly reducing process passability. Furthermore, when ordinary heat-shrinkable multifilament undergoes heat treatment during sizing, etc., the heat set is almost fixed, and even when subjected to high-temperature heat treatment of about 160 to 180 degrees Celsius during final setting, the yarn length difference is not much greater than that at the initial heat setting. However, by including multifilaments like the composite yarn of the present invention, which shrink in hot water but elongate in high-temperature heat treatment equivalent to final set, multifilaments can be formed by finishing at a higher temperature than the shrunk fabric surface as a whole. Filament A protrudes in a loop shape, providing a soft and flexible touch as if it were the surface of a peach. For this purpose, it is sufficient that SHW(A)≧0% and SHD(A)≦0%. SHD for further swelling and bulkiness
It is appropriate that (B)-SHD(A)≧5%; if it is less than 5%, swelling and bulkiness will be poor and it will be excluded from the present invention. However, if it is too large, the protruding loops from the surface will be too large, which tends to cause problems such as "shininess" when ironing, etc., so it is preferably 50% or less. Also, for the same reason, SHW (
A) is preferably 5% or less, and SHD(A) is preferably -15% or more. Next, the reason why the elongation at break of multifilament A is 50% or more is to obtain a soft and flexible texture. Generally, in order to obtain a soft feel with polyester, it is easier to obtain a filament with a small SHW and a large elongation at break. As described in detail above, it is the spontaneously elongated multifilaments that form loops and cover the surface of the fabric, and the touch of these multifilaments determines the touch of the fabric. However, if the elongation at break is too large, handling becomes poor, so it is less than 100%, more preferably 80%.
The following is good. Next, the elongation at break of multifilament B is 4.
The content is preferably 0% or less because it prevents yarn unevenness from occurring due to elongation of the composite yarn in subsequent processes such as winding, knitting, and weaving. Furthermore, this is to prevent problems such as the knees coming off in the product after it is made into a fabric. Furthermore, the breaking strength of the composite yarn is also substantially dependent on the heat-shrinkable multifilament, so the breaking strength of the heat-shrinkable multifilament must be at least 4 g/denier and at least 20% of the denier ratio of the composite yarn. Of course, if the breaking strength is high, the proportion of multifilament B may be slightly lower, but if it is less than 20%, the shrinkage force of multifilament B will be small and the bulge due to the difference in yarn length will not be expressed, so it is excluded from the present invention. still,
The hot water shrinkage rate and the 160°C dry heat shrinkage rate of the multifilament B are preferably 5 to 60% and 7 to 80%, respectively. [0011] The multifilament B may also be a so-called thick-and-thin yarn having thickness unevenness in the fiber axis direction. However, in that case, the hot water shrinkage rate may be 5 to 30%. Thick and thin yarn has an orientation degree (△n) of 1 in the thin part, considering the retention of yarn physical properties after post-processing.
5 to 60×10 −3 or more, more preferably 160×1
0-3 or more is good. Generally, when thick and thin yarn is dyed, it exhibits a difference in shading, but the difference in shading is too strong.However, by heat-treating the blended yarn of this invention, the thick and thin yarn is in the inner layer, and the multifilament A is placed on the outer layer, and the excessively strong shade difference of Thick and Thin yarn is hidden by Multifilament A yarn to create a natural color tone difference. Next, the multifilament A must be composed of single filament denier of 3 denier or less. If it exceeds 3 denier, the elongation at break is large and the texture becomes rough and hard even if the Young's modulus is low, so it is excluded from the present invention. However, if the filament is too thin, even filaments with irregular cross-sections, which will be described later, will become stiff and lose their stiffness, so a denier of 0.2 denier or more is preferable. However, it may be mixed with 3 deniers or more (denier mix), as long as it has an average of 3 deniers or less. Further, it is preferable that the filament has an irregular cross section having at least one recess on the outer peripheral surface of the cross section. In particular, filaments with a high breaking elongation such as the composite yarn of the present invention are soft but tend to feel slimy, so by making the cross-sectional shape irregular, the number of point contacts between the filaments increases, resulting in a soft, dry touch. . Here, the irregular cross-section refers to a triangular, hexagonal, oblate, hollow, etc. cross-sectional shape having at least one recess on the outer peripheral surface of the cross-section. Shown in Figure 3. In order to have such a texture and effect, it is preferable that the fiber is composed of 10 or more filaments of these single yarns. Next, the present composite yarn has a substantially core/sheath structure because the multifilaments A are present in large quantities in the surface layer of the composite yarn, so that the loops tend to protrude from the surface of the fabric. Furthermore, the term "substantially having a core/sheath structure" as used herein means only a structure in which the composite yarn is divided into a core part and a sheath part, that is, multifilament B and multifilament A, at a certain interface. It also means a structure in which both components are mixed throughout the composite yarn, especially near the interface, and multifilament B is mainly arranged in the core and multifilament A is mainly arranged in the sheath. Multifilament B is larger than multifilament A in terms of weight ratio within 1/3 radius from the center of the composite yarn, and multifilament A is larger than multifilament B within 1/3 radius from the surface of the composite yarn. It is within the scope of the invention. The core/sheath structure and the above-mentioned denier ratio are measured by fixing the composite yarn with epoxy resin, cutting the cross section randomly 100 times, observing it with an optical microscope, and determining the average value and condition from this. It is also essential that they are entangled with a degree of entanglement of 20 to 100. When the degree of entanglement is less than 20, when the multifilaments are squeezed, the threads tend to separate due to the difference in thread length, which significantly impedes processability. On the other hand, the degree of confounding is 1
If it exceeds 00, interlacing spots will become noticeable on the fabric, and the monofilaments of multifilament A may break, resulting in fluff, which is not preferable. Next, the cross section of the multifilament B constituting the inner layer part is not particularly limited, but in order to provide bulkiness, hollow fibers are used, and in order to further emphasize the dry hand, the cross section of the multifilament B is similar to that of the multifilament A. Also preferred are irregular cross-section threads having at least one recess on the outer circumferential surface. Furthermore, the polyester composite yarn of the present invention contains multifilament A.
If necessary, both or one of the component and the multifilament B component may contain a polyester fiber containing a copolymer of 5-sodium sulfonic acid metal salt, isophthalic acid, etc., or a fine powder inert substance. Next, it is also preferable that the present composite yarn is in a twisted state. However, if the yarn is twisted too strongly, it is difficult to create a difference in yarn length, so the yarn length is preferably 15,000/(D)1/2 (T/m) or less, but it is not necessarily limited to this when softness and flexibility are not required. The structure and effects of the present invention will be explained with reference to the following examples, but the present invention is not limited to the following examples. [Example] The measurement method carried out in the present invention is as follows. (1) Elongation at break According to JIS-L-1013 (1981), sample length (gauge length) 2 using Tensilon manufactured by Toyo Baldwin Co., Ltd.
The SS curve was measured at a tensile speed of 00 mm and a tensile speed of 200 mm/min, and the elongation at break was calculated. (2) Heat shrinkage rate (SHW), dry heat shrinkage rate (
SHD) According to JIS-L-1073, the following was carried out. In other words, with a wrap reel of appropriate frame circumference, the initial load is 1/10g/denier and it is 8.
Take the winding skein, apply a load of 1/30 g/denier to the skein, and measure its length L0 (mm). Then, the load was removed, and the skein was immersed in boiling water for 30 minutes with a load of 1/1000 g/denier applied. Thereafter, the skein was removed from the boiling water, and after cooling, a load of 1/30 g denier was applied again to measure the length L1 (mm). Then, after drying at 60℃ for 30 minutes, 1/1000g
Heat treatment is performed in a dry heat oven at 160° C. with a load of /denier applied. Then, after cooling, a load of 1/30 g/denier was applied again to measure the length L2 (mm). Hot water shrinkage (SHW), dry heat shrinkage (SHD)
is calculated by the following formula. SHW=(L0-L1)×100÷L0 SHD
(L0 - L2 )×100÷L0 0020】(
3) Degree of entanglement Take out a thread of appropriate length and hang it vertically by applying a load of 1/10 g/denier to the lower end. Next, a suitable needle is inserted into the thread, and the needle is slowly lifted to measure the distance L (cm) traveled until the load is lifted 100 times. From this, the average value L (cm) is determined and calculated using the following formula. Degree of entanglement = 100 ÷ (2 × L) Examples 1 to 3 Comparative Examples 1 to 8 Heat-stretched multifilament made of ordinary polyester was drawn in a conventional manner at a winding speed of 3000 m/min. Denier after relaxation: The spinning discharge rate, stretching ratio, relaxation rate, relaxation temperature,
The heat-shrinkable multifilament obtained by changing the setting time was commercially available, Toyobo Ester manufactured by Toyobo Co., Ltd., and Figure 1
The film was processed using a stretch-relaxation machine. Here, Air Jet FG-1 manufactured by Fiber Guide Co., Ltd. was used as the air nozzle 7, and the air pressure and the feed ratio between the feed roller 6 and the delivery roller 8 were adjusted so as to obtain the target degree of entanglement. The physical properties of the raw yarn used, the yarn quality of the obtained composite yarn, and the yarn were subjected to a sizing process after twisting in a conventional manner, and then the texture of the fabric, which was woven with deshine and dyed and finished, was evaluated. In addition, as for process passability, the yarn twisting, winding and weaving properties were evaluated in particular, and the comprehensive evaluations from the aspects of process passability and texture are listed in Tables 1 to 3, respectively. Examples 1 and 2 had good texture and process passability within the scope of the present invention. In Comparative Example 1, the SHW of the heat-stretched multifilament was negative, loops were generated even during sizing (heat-stretched), and openings were poor during weaving, causing problems in process passability. In Comparative Example 2, the heat-stretched multifilament did not shrink and there were no protruding loops on the surface of the fabric, and only the same texture could be obtained from ordinary differentially shrinkable mixed fibers. In Comparative Example 3, the elongation at break of the heat-stretched multifilament was as low as 40%, so the surface touch was somewhat rough and hard, which was not good. In Comparative Example 4, the elongation at break of the heat-shrinkable multifilament was as high as 50%, so the elongation at break of the composite yarn was also large, causing unevenness due to tension, and puckering also occurred in the fabric. In Comparative Example 5, the ratio of heat-shrinkable multifilament (ratio to composite yarn denier) was as low as 18%, so the strength of the composite yarn was low and yarn breakage occurred, and the texture was also stiff.
There was no waist and it was not satisfying. On the contrary, in Comparative Example 6, the ratio of heat-shrinkable filaments was as high as 90%, so there were few heat-shrinkable filaments protruding from the surface of the fabric, causing bulges and
It had a poor bulky feel. In Comparative Example 7, the degree of entanglement was low, so the threads separated and the processability was poor. In Comparative Example 8, since the degree of entanglement was as high as 130, moiré spots called interlace marks occurred on the fabric. [Table 1] [Table 2] [Table 3] D: Total denier Fil: Number of filaments Cross-sectional shape: △ Triangular cross-section in Figure 3, 1, ○ Round cross-section Fabric texture: Tactile sensory evaluation by 10 people 4-level evaluation ◎
Soft feel, firmness, waist, and drape feel are all good.
Lack of soft feel△ Lack of soft feel, drape feeling Judgment: ◎ Both are good △ One or both have defects × One or both are very bad [0024] Examples 3 to 7, Comparative Examples 9 to 17 Polyethylene terephthalate with an intrinsic viscosity of 0.63 was prepared by a conventional method. The undrawn yarn shown in Table 4 was obtained by using a spinning nozzle with 18 holes and changing the spinning speed and discharge amount. Subsequently, mixed fiber yarns were produced under the conditions shown in Tables 5 and 6, and were woven and dyed in a conventional manner. During this time, the process passability was evaluated for stretching workability, relaxing heat treatment workability, post-processing passability such as weaving, as well as textile texture and appearance, and the results are also shown in Tables 5 and 6. A drawing, relaxing, and blending machine shown in FIG. 1 was used to create the mixed fiber yarn. The degree of entanglement was adjusted using Air Jet FG-1 manufactured by Fever Guide Co., Ltd., and the air pressure and processing tension were adjusted. Examples 3 to 7 were within the scope of the present invention and had excellent process passability, weave, woven fabric appearance, and texture. In Comparative Examples 10 and 11, the elongation at break after stretching was outside the scope of the present invention, and in Comparative Example 10, the elongation at break after stretching was high, uneven thickness was observed during stretching, and the texture and appearance of the fabric were not uniform. It wasn't something I could feel satisfied with. Also, comparative example 1
Sample No. 1 had a low elongation at break after stretching and Δn was also outside the scope of the present invention, but its stretching operability was poor, and process passability was accordingly reduced. In Comparative Examples 12 and 13, the relaxation heat treatment temperature was outside the scope of the present invention, and in Comparative Example 12, the relaxation heat treatment temperature was low and the fabric lacked spontaneous elongation and had an unsatisfactory woven texture. In addition, in Comparative Example 13, the relaxation heat treatment temperature was high, fusing yarn breakage occurred at the time of doffing and stopping, and the texture of the fabric was also slightly unsatisfactory. In Comparative Examples 14 and 15, the overfeed rate during relaxing heat treatment was outside the scope of the present invention, and in Comparative Example 14, the feel was unsatisfactory due to lack of spontaneous elongation. Comparative Example 15 had a high overfeed rate, resulting in a decrease in ease of operation during the relaxing heat treatment, and furthermore, the mixed yarn had many loops, resulting in poor post-processing passability and fabric texture. In Comparative Examples 16 and 17, the mixed fiber denier ratio of spontaneously extensible multifilament and heat-treatable multifilament is outside the invention, and in Comparative Example 16, the ratio of heat-shrinkable multifilament is high, and the fabric lacks a soft feel. there were. Furthermore, Comparative Example 17 had a low ratio of heat-shrinkable multifilament and lacked elasticity. [Table 4] [Table 5] [Table 6] [0027] Den: Total denier fil: Number of filaments
◎ ○
△ × Drawing operability: drawing thread cut rate
2% or less 5% or less 10% or less 11
% or more relaxed Operability: relaxed Thread trimming rate
2% or less 5% or less 10% or less 11% or more Post-process passability: Loom operation rate 98% or more
95% or more 90% or more Less than 90% Fabric texture:
4-level evaluation based on tactile sensory evaluation by 10 people ◎ Soft feel, tension, waist, and drape feeling are all good ○ Lack of soft feel △ Lack of soft feel and drape feeling Irregularities, streaks, and other defects were evaluated on a four-level scale ◎ None ○ Slightly noticeable △ Conspicuous × Extremely noticeable Overall: Comprehensive evaluation of process operability, passability, fabric texture, and appearance ◎ All good △ [Effects of the invention] As described above, the polyester composite yarn of the present invention is softer and more flexible than the conventional differential shrinkage mixed fiber yarn (including heat-stretched yarn). Sexy, dry touch, moderate tension, waist,
It has the remarkable effect of having good drapability and excellent process passability. [0029]

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of a manufacturing apparatus according to the present invention.

FIG. 2 is a side view of the composite yarn obtained according to the present invention that has been heat-treated to develop a yarn length difference.

FIG. 3 is a representative example of the cross-sectional shape of a single filament in the present invention.

[Explanation of symbols]

A: Heat-stretched multifilament B: Heat shrink multifilament C: Polyester composite yarn of the present invention 3: Hot roller 5: Non-contact heater 7: Air jet nozzle

Claims (1)

[Claims] [Claim 1] A polyester multifilament with a multifilament drawn yarn having a breaking elongation of 30 to 45% and Δn of 0.10 to 0.14 as described below [A] using a non-contact heater.
Polyester multifilament A satisfying the following formula [B] obtained by performing relaxing heat treatment at a heater temperature T (°C) that simultaneously satisfies formulas (1) and (2) and an overfeed rate of 20 to 60%. and polyester multifilament B at A/B=20-80%/
A method for producing a latent bulky polyester composite yarn for woven or knitted fabrics, characterized in that the yarn is entangled at a degree of entanglement of 20 to 100 threads/m so that the denier ratio is 80 to 20% (denier ratio). [A]75log {(D×Vy)1/2 /HL}+
4.7(Vy)1/2 ≧T≧25log {(D×V
y)1/2/HL}+4.7(Vy)1/2...
(1) T≦Tm-10...(2) D: Denier after relaxation V: Relaxation trading roller speed (m/min) HL:
Relaxed non-contact heater length (m) Tm: Melting point (°C) Tg: Secondary transition temperature (°C) [B] SHW (A) ≧0%, SHD (A) ≦0% SHW
(B)≧0% SHD(B)-SHD(A)≧5% DE(A)≧50% SHW: Hot water (100°C) shrinkage rate (%) SHD: Dry heat (
160℃) Shrinkage rate (%) DE: Breaking elongation (%)