JPH08209472A - Production of thin-thick processed yarn having high stretchability - Google Patents

Abstract

PURPOSE: To provide a method for producing a thin-thick processed yarn having high stretchability and useful for a woven fabric having stretchability on espe cially a warp yarn or a weft yarn or both yarns, in which the thin-thick processed yarn is made of crimped multifilaments excellent in stretchability and having thick parts and thin parts on each polyamide filament and having properties to produce light and shade difference when the yarn is dyed as knit or woven fabric. CONSTITUTION: A polyamide undrawn yarn having birefringence (Δn) of 15×10-<3> to 30×10-<3> is subjected to a heat treatment at a temperature of 110 deg.C to 200 deg.C and at a feed ratio of -20% to +20% to obtain a degree of crystallization of >=35%. Subsequently, the heat-treated undrawn yarn is drawn at a draw ratio of 1.2 to 3.0 to obtain a multifilament yarn consisting of filaments having variable cross-sectional areas in the fiber axis direction. The treated multifilament yarn is subjected to a false twist processing at a false twist number of 15000/D<1/2> (T/M) to 38000/D<1/2> (T/M) (D is denier of the multifilament yarn) and at a false-twist temperature of 120-210 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crimped multifilament yarn in which individual polyamide filaments have a thick portion and a thin portion, and when a woven or knitted fabric is dyed, a difference in color density is exhibited, which is excellent in stretchability. In particular, the present invention relates to a method for producing a highly elastic thick and thin textured yarn suitable for warp or weft, or a fabric having elasticity in the weft.

[0002]

2. Description of the Related Art Conventionally, many false twisted yarns having unevenness in thickness and difference in dyeing ability in the longitudinal direction of the yarn have been proposed. For example, Japanese Patent Publication No. 51-7207, Japanese Patent Publication No. 53-27387, Japanese Patent Publication No. 53-36051, Japanese Patent Publication No. 53-45418, and Japanese Patent Publication No. 58.
-12946, Japanese Patent Publication No. 58-37417, Japanese Patent Publication No. 59-5686
Japanese Patent Publication No. 59-20003, Japanese Patent Publication No. 59-59926, and the like disclose a multi-filament yarn having a thickness unevenness in the longitudinal direction of the yarn, which is a false twist in the longitudinal direction of the yarn. A crimped yarn having a dyeing difference is disclosed.

[0003]

However, although all of these textured yarns are excellent in terms of feeling and surface effect, they are not sufficient in terms of functions such as stretchability because of their low stretchability due to crimping. Therefore, it was difficult to apply to stretchable fabrics. Stretchable woven fabrics are usually woven fabrics with an elongation of 20% or more, but woven fabrics obtained from these processed yarns are
I could not satisfy this.

The present invention solves the above-mentioned conventional drawbacks, and an object thereof is a method for producing a highly elastic thick and thin processed yarn having a surface effect due to a color difference between light and shade and a high elasticity function. To provide.

[0005]

The inventors of the present invention have reached the present invention as a result of intensive research aimed at eliminating the above-mentioned drawbacks of the prior art. That is, the present invention is based on the birefringence (Δn)
The unstretched polyamide yarn of 15 × 10 ^-3 to 30 × 10 ^-3 was heat-treated at a heat treatment temperature of 110 ℃ to 200 ℃ and a feed rate of -20% to + 20% to obtain a crystallinity of 35% or more. A heat-treated undrawn yarn is drawn at a draw ratio of 1.2 to 3.0 to form a multifilament yarn composed of a filament whose cross-sectional area varies in the fiber axis direction. / D ^1/2 (T / M) ~ 38000 / D ^1/2 (T /
M) (however, D is denier of multifilament yarn),
A gist of the present invention is a method for producing a highly stretchable thick and thin textured yarn, which is characterized by performing false twisting at a false twisting temperature of 120 to 210 ° C.

[0006]

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

In the present invention, first, the birefringence Δn is 15 × 10 ^−3.
Approximately 30 × 10 ^-3 undrawn polyamide yarn with a crystallinity of 35
%, And heat treatment at a feed rate of -20% to + 20% at a temperature of 110 ° C to 200 ° C. Here, the feed rate is a percentage of the difference between the supply speed and the take-up speed with respect to the take-up speed.

In the present invention, the birefringence Δn is 15 × 10 ⁻³
It is necessary to use undrawn polyamide yarn of ~ 30 × 10 ^-3 , and if undrawn polyamide yarn with birefringence Δn is less than 15 × 10 ^-3 , brittleness is caused by heat treatment and Thread cutting easily occurs and processing becomes difficult. On the other hand, when polyamide undrawn yarn with birefringence Δn of more than 30 × 10 ^-3 is used, non-uniform drawing accompanied by necking cannot be performed even after drawing after the subsequent heat treatment, and the cross-sectional area in the fiber axial direction cannot be achieved. The fluctuation that fluctuates is not obtained.

In the present invention, in order to draw the polyamide undrawn yarn non-uniformly, it is necessary to increase the crystallinity to 35% or more, unlike the polyester undrawn yarn. When the crystallinity is 35% or more, many crystal blocks are formed in the structure of the polyamide undrawn yarn, and the crystal blocks act to prevent uniform drawing during drawing, causing non-uniform drawing. It is possible.

Therefore, in order to obtain a crystallinity of 35% or more, the heat treatment temperature is 110 ° C to 200 ° C and the feed rate is -20%.
It is necessary to perform heat treatment within the range of + 20%. If the heat treatment temperature is less than 110 ° C, the crystallinity cannot be increased to 35% or more, while if it exceeds 200 ° C, the filament is melted and the filament is easily broken or brittle. On the other hand, when the feed rate is less than -20%, the birefringence Δn becomes 30 × 10 ^-3 or more due to the strong stretching action, and the nonuniform stretching cannot be performed in the subsequent stretching. When heat-treating the above polyamide undrawn yarn, the birefringence is greatly increased by more than 30 × 10 ^-3 by heat treatment, for example, when heat treatment is performed while giving high elongation, the heat-treated yarn is treated as described below. Even if it is stretched, it cannot be stretched unevenly. The reason is that when the birefringence Δn increases substantially and becomes 30 × 10 ^-3 or more, the molecular chain has already been extended and the structural transition process from the lumpy structure to the bundled structure is observed regardless of the crystallinity. This is because the non-uniform stretching that occurs in 1. cannot be generated.
On the other hand, if the feed rate exceeds + 20%, the heat shrinkage of the polyamide undrawn yarn becomes insufficient and the yarn becomes slack, which makes it difficult to process. The above heat treatment is preferably performed at a heat treatment temperature of 130 ° C to 180 ° C and a feed rate of -5% to + 5%. In the subsequent stretching, nonuniform stretching can be performed in a particularly stable state, and a clear A yarn having unevenness in thickness is obtained.

Then, the heat-treated polyamide undrawn yarn is drawn at a draw ratio of 1.2 to 3.0, and necking is generated in each filament, so that filaments whose cross-sectional area varies in the fiber axis direction are drawn. Multifilament yarn That is, stretching is performed at a draw ratio of 1.2 to 3.0 times to carry out non-uniform stretching, and the cross-sectional area varies in the fiber axis direction, and the cross-sectional area ratio between the thick and thin portions is 1.2 to 4.0. To form multifilament yarns. Here, if the draw ratio is less than 1.2 times, it is difficult to carry out the non-uniform drawing, and even if the non-uniform drawing occurs, what is recognized as a filament having unevenness in thickness is not formed. On the other hand, when the draw ratio exceeds 3.0 times, the thick part disappears due to drawing, and it becomes easy to obtain a uniform drawn yarn,
It is difficult to obtain filaments whose cross-sectional area varies in the fiber axis direction. Although it depends on the birefringence and crystallinity of the heat-treated undrawn yarn, when obtaining a filament with an appropriate thickness unevenness, for example, when obtaining a filament with a cross-sectional area ratio of 1.5 to 3.0, 1 It is preferable to adopt a draw ratio of 0.5 to 2.5 times.

In the above stretching, in order to cause nonuniform stretching, it is preferable to perform cold stretching, particularly at room temperature. In particular, it is effective to perform drawing at room temperature in order to obtain a yarn made of filament having clear thickness unevenness. However, it is also possible to stretch under heating in order to easily control the phase of the thick part, the length of the thick part, and the frequency. However, in order to draw non-uniformly under heating, the drawing temperature is the glass transition temperature (Tg) of the heat-treated undrawn yarn.
Keep the temperature below + 20 ℃.

Thereafter, the multifilament yarn, which is obtained by the above-mentioned drawing and is composed of a filament whose cross-sectional area varies in the axial direction of the fiber, is false twisted to obtain a target highly stretchable thick and thin yarn. The number of false twists during the false twist process is 15000 / D.
^1/2 (T / M) to 38000 / D ^1/2 (T / M), false twist temperature is 1
It is necessary to perform false twisting at 20 ℃ to 210 ℃. Here, D is the denier of the multifilament yarn obtained by the above drawing. False twist number is 15000 / D ^1/2 (T / M)
If it is less than 100%, it is difficult to obtain a processed yarn having a stretch elongation rate of 20% or more,
On the other hand, when it exceeds 38000 / D ^1/2 (T / M), the thick portion is elongated due to the yarn breakage due to twisting or strong torsional deformation, and it is difficult to form a clear thickness unevenness. Especially, in order to obtain stable processing operability and a high expansion / contraction rate, 28000 / D
^1/2 (T / M) to 35000 / D ^1/2 (T / M) is preferable. Further, if the false twist temperature is less than 120 ° C, the crimp is not fixed, and it is difficult to obtain a textured yarn having an expansion / contraction elongation ratio of 20% or more. On the other hand, if the false twist temperature exceeds 210 ° C, fusion between filaments easily occurs. After all, it is difficult to obtain a processed yarn with a stretch elongation rate of 20% or more. In particular, it is preferable to adopt a false twisting temperature of 150 ° C to 190 ° C in order to obtain a high stretching elongation rate.

The highly stretchable thick and thin processed yarn obtained by the present invention is
First, it is a crimped multi-filament yarn composed of a polyamide filament whose cross-sectional area varies in the fiber axis direction and the cross-sectional area ratio between thick and thin portions is 1.2 to 4.0. Here, when a woven fabric using crimped multi-filament yarn having a filament cross-sectional area ratio of less than 1.2 is dyed, a sufficient shade difference cannot be obtained and an effective surface effect cannot be obtained. On the other hand, when the cross-sectional area ratio of the filament exceeds 4.0, the yarn fineness becomes unnecessarily thick due to the overlapping of the thick parts of the filament. Therefore, when dyeing a fabric using the crimped multi-filament yarn, It is not preferable because the parts are emphasized too much and the surface is very uneven, and the deep dyed part is easily worn away when worn. When the cross-sectional area ratio of filaments is in the range of 1.2 to 4.0, in the case of yarns in which the phases of the thick parts between filaments are relatively uniform, the thinness is emphasized and morphological changes such as slabs occur in the fabric. In the case of a given yarn, in which the phases between filaments are not uniform, gentle unevenness due to the difference in the form of yarn unevenness and particularly deep color tone are obtained, and a woven fabric with a preferable surface effect is obtained. In particular, it is more preferable to set the cross-sectional area ratio of filament to 1.5 to 3.0 in order to obtain a clear color difference and prevent abrasion of the convex portions on the textile product. Here, regarding the cross-sectional area ratio of filaments, the filaments that compose it are taken out from the multi-filament yarn, and the cross sections of the thick part and the thin part are photographed with an optical microscope at 30 locations respectively. It is calculated from the average value of the cross-sectional area of the part.

Next, the highly stretchable thick and thin textured yarn obtained by the present invention is required to have a stretch elongation rate of 20% or more,
Particularly, 50% or more is preferable. Since the polyester fiber has a benzene ring in the molecular chain, it has low flexibility and high Young's modulus. Therefore, even if the polyester multifilament yarn is false twisted and crimped, the expansion and contraction rate due to the crimping is usually about 10%, which is as low as about 15% at maximum. In order to increase the expansion and contraction rate due to this crimp, there is no molecular structure that inhibits the flexibility of the fiber such as benzene ring in the molecule,
Nylon 6, Nylon 6.6, Nylon 6, 10 that have hydrogen bonds at appropriate intervals and contribute to the elasticity of the fiber
Polyamide fiber yarns such as are effective. When a crimped yarn made of polyamide fiber is applied, it is possible to easily obtain a performance with a stretching elongation rate of 20% or more.

When the stretch elongation of the processed yarn is less than 20%, it is not possible to obtain a stretch fabric having a stretch ratio of more than 20%. If the stretch elongation of the processed yarn is 20% or more, it is possible to easily obtain a stretchable woven fabric with the stretch ratio of more than 20%. Furthermore, if the stretch elongation of the processed yarn is 50% or more, the high stretchability is obtained. Can be applied to functional clothing such as sports clothing that requires.

The highly stretchable thick and thin processed yarn obtained by the present invention is
It is most suitable for stretchable fabrics, but it can also be used for other fabrics or by twisting and weaving with other yarns. Furthermore, it can be appropriately applied to other knitting applications and the like, as well as knitting such as swimwear that particularly needs elasticity.

Next, the present invention will be described with reference to the drawings.
FIG. 1 is a schematic process diagram showing an embodiment of the present invention.
In FIG. 1, a polyamide undrawn yarn 2 drawn from a spool 1 is supplied to a heat treatment area by a feed roller 3, where it is heat treated by a heat treatment heater 4, and then cold drawn between a delivery roller 5 and a drawing roller 6 at room temperature. To be done. Next, the yarn that has exited the drawing roller 6 is subjected to false twist crimping processing by a false twist heater 7 and a false twist twisting device 8, taken up by a delivery roller 9, and taken up by cheese 10 by a take-up roller 10.

In the above example, an example in which all the steps are processed continuously has been shown, but it is also possible to wind them once in the heat treatment step or the drawing step and then supply them to the next step. Further, the false twisting and twisting device 8 normally uses a mechanical spindle, but a frictional spindle or a false twisting and twisting device using a fluid nozzle that produces a swirling flow may be used.

In the present invention, the crystallinity is calculated from the following equation by measuring the density by the density gradient tube method. 1 / d = Xc / dc + (1-Xc) / da, where Xc: crystallization rate [Crystallinity; 100 Xc (%)] d: density of measured sample (g / cm ³ ) dc: perfect crystal part Density (g / cm ³ ) da: Density of completely non-crystalline part (g / cm ³ ) Here, in the case of nylon 6, dc = 1.230 g / cm ³ , d
a = 1.084 g / cm ³ .

The expansion and contraction rate is JIS-L-10090.5.7.
Synthetic fiber filament Highly textured yarn Stretchability Measured by the C method (no wet heat treatment). The elongation rate of the woven fabric is JIS-L-109
6.6.14 Stretchability of stretch fabric 6.14.1 Elongation rate Measured by the A method.

[0022]

In the method for producing a highly stretchable thick and thin textured yarn of the present invention, the above-mentioned specific polyamide undrawn yarn is heat-treated at a specific heat-treatment temperature and a feed rate to obtain a crystallinity of 35% or more, Then, the filament is stretched at a specific stretching ratio to give non-uniform stretching to form a multi-filament yarn composed of a filament having a thick portion and a thin portion whose cross-sectional area varies in the fiber axis direction. The reason for this is that by first heat-treating the polyamide undrawn yarn as described above, the amorphous molecular chains are incorporated into the crystal structure in a hold state, and the birefringence hardly increases and the lump with increased crystallinity is obtained. It becomes a structure. When this multifilament yarn is drawn at a specific draw ratio, the molecular chains are unraveled by the stress at the time of drawing, and the molecular chains try to form a bundle-like structure in which the molecular chains are elongated, but the crystallinity increases and the crystal size increases accordingly. As a result of the increase of, the unraveling of this molecular chain cannot be performed smoothly,
Uniform stretching is hindered, and necking occurs around the portion that is relatively susceptible to stress concentration, resulting in uneven stretching. As a result, thick and thin portions are formed in each filament. It is considered to be a thing. Next, the drawn multifilament yarn is false-twisted. By heat-treating and drawing the polyamide multifilament yarn with individual filaments having uneven thickness, false-twisting is performed to obtain a stretch elongation ratio of 20% or more. A textured yarn having a high stretch elongation ratio is formed.

The highly stretchable thick and thin textured yarn obtained by the present invention is a crimped multi-filament yarn composed of a polyamide filament having a cross-sectional area ratio of a thick portion and a thin portion of 1.2 to 4.0. Therefore, this cross-sectional area ratio is appropriate, warping, thread cutting during weaving and knitting, fluffing, etc. are less likely to occur, it is excellent in practicality, and it is possible to satisfy the shade effect. Furthermore, since the stretch elongation rate is higher than 20%, it is possible to obtain a woven and knitted fabric with extremely high stretchability.

[0024]

EXAMPLES Next, the present invention will be specifically described by way of examples. Example 1 Birefringence 19.5 × 10 ⁻³ , crystallinity 30.2% (density 1.1244 g / cm
³ ) Nylon 6 multifilament undrawn yarn 267d / 24
f is heat-treated under the conditions shown in Table 1 according to the process shown in FIG.
Cold-drawn (drawing temperature is room temperature of 25 ° C), false twisting is performed, and the crimped multi-filament yarn is composed of thick and thin filaments with a cross-sectional area varying in the fiber axis direction and a cross-sectional area ratio of 1.85 for thick and thin portions. Got However, a mechanical spindle was used as the false twisting device. The birefringence and crystallinity were measured by collecting the yarn after heat treatment, and the birefringence was 21.5 ×
The crystallinity was 10 ^-3 and the crystallinity was 40.3% (density 1.1386 g / cm ³ ).

[0025]

[Table 1]

The obtained high-elasticity thick and thin textured yarn was used as a warp yarn having a density of 108 yarns arranged per 2.54 cm of the reed, and the surface design was 2/2.
88 wefts per weft design, back design 3/1 italic density 2.54 cm were woven, and then dyed and finished by a conventional method.
The resulting stretchable woven fabric had a heathered appearance due to the difference in color between light and shade, and had a performance of 43% elongation in the weft direction.

Example 2 Birefringence 22.0 × 10 ⁻³ , crystallinity 32.6% (density 1.1276 g / cm 3
³ ) Nylon 6 multifilament undrawn yarn 193d / 16
After heat-treating f under the conditions shown in Table 2, cold stretching (stretching temperature is 25 ° C
At room temperature), the product was once wound and then false twisted to obtain a crimped multifilament yarn having the yarn quality shown in Table 2. The birefringence and crystallinity of the yarn after heat treatment were measured, and the birefringence was 23.1 × 10 ^-3 and the crystallinity was 43.0% (density 1.1423g.
/ Cm ³ ).

[0028]

[Table 2]

The obtained highly stretchable thick and thin textured yarn was 110 micrograms per warp density of 2.54 cm and weft density of 2.54c in the structure chart shown in FIG.
Weaving was carried out with 103 yarns per m, and then dyed and finished by a conventional method. The stretchable fabric obtained had a heather appearance due to the difference in shades of light and shade, and had a stretch ratio of 35% in the warp direction and 43% in the weft direction.

[0030]

EFFECTS OF THE INVENTION According to the present invention, it is possible to easily fabricate a highly stretchable thick and thin textured yarn capable of imparting to a fabric obtained by weaving and knitting, a favorable surface effect due to a difference in color tone and functionality excellent in stretchability. It becomes possible to obtain it.

[Brief description of drawings]

FIG. 1 is a schematic process diagram showing an embodiment of the present invention.

FIG. 2 is a structural diagram showing one embodiment of a woven fabric made of a highly elastic thick and thin processed yarn obtained by the present invention.

[Explanation of symbols]

 2 Polyamide undrawn yarn 4 Heat treatment heater 7 False twist heater 8 False twist device

Claims (1)

[Claims] 1. Crystallization by heat-treating undrawn polyamide yarn having a birefringence (Δn) of 15 × 10 ⁻³ to 30 × 10 ⁻³ at a heat treatment temperature of 110 ° C. to 200 ° C. and a feed rate of −20% to + 20%. The unstretched yarn that has been treated with a degree of conversion of 35% or more and then heat treated has a draw ratio of 1.2.
~ Multi-filament yarn consisting of filaments with a cross-sectional area varying in the fiber axis direction drawn by 3.0 times, and then the above-mentioned multi-filament yarn with a false twist number of 15000 / D
^1/2 (T / M) to 38000 / D ^1/2 (T / M) (where D is the denier of multifilament yarn), false twist temperature 120 ° C to 2
A method for producing a highly stretchable thick and thin textured yarn, which comprises false twisting at 10 ° C.