JPH09228154A - Production of polyester conjugate fiber with latent crimp tendency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conjugate fiber having high mechanical strength and low elongation, spinnable in high speed in the form of short fiber and capable of giving friction-resistant fabrics or nonwoven fabrics. SOLUTION: This conjugate fiber has the following characteristics: (A) a polyester composed mainly of ethylene terephthalate unit and (B) a polyester copolymerized with 1-4.5mol% isophthalic acid and 2-7mol% bisphenol A ethylene oxide adduct are conjugated together eccentrically; the shrinkage in free shrink heat treatment at 170 deg.C is <=15%; the number of spiral crimps manifesting by heat treatment under relaxation at 170 deg.C is >=50/25mm; elongation is <=25%; and tenacity is >=6.5g/d. To obtain this conjugate fiber, drawing operation is carried out in two stages; 1st stage drawing in a draw ratio 70-95% of the total draw ratio, followed by 2nd stage drawing under passage through a heat steamer at 130-170 deg.C for a residence time of 0.5s or longer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a latently crimpable polyester composite fiber which exhibits spiral crimps when heat-treated and has good stretchability.

[0002]

2. Description of the Related Art Polyester fibers are used for various purposes such as clothing and industrial materials. Above all, in sports clothing applications, highly stretchable fibers are desired. In order to obtain highly stretchable fibers, a large number of latent crimpable conjugate fibers have been proposed in which polymers having different heat shrinkage properties are compounded in a side-by-side or eccentric core-sheath structure.

For example, Japanese Patent Publication No. 4-5769 and Japanese Patent Publication 3
No. -10737 discloses a composite fiber of polyethylene terephthalate and a polyethylene terephthalate-based copolyester obtained by copolymerizing a 5-sodium sulfoisophthalic acid component. Further, Japanese Patent Application Laid-Open No. 7-54216 discloses a composite fiber of polyester and polyethylene terephthalate obtained by copolymerizing isophthalic acid and an ethylene oxide adduct (BAEO) of bisphenol A.

Since these conjugate fibers can be obtained by a general yarn making method, the elongation is about 30 to 50% and the strength is low. Therefore, the fabric obtained by weaving and knitting this composite fiber has a problem that when it is used for sports clothing, it is easily broken when subjected to sliding force and frictional force. Further, since the elongation is high and the strength is low, there is a problem that these conjugate fibers cannot speed up the spinning process.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and if short fibers are used, it is possible to obtain a cloth or a non-woven fabric which can be spun at high speed and is resistant to friction. It is a technical object to provide a method for producing a latently crimpable polyester conjugate fiber having low elongation and high strength.

[0006]

The present inventors have arrived at the present invention as a result of intensive studies to solve such problems. That is, the present invention relates to a polyester (A) mainly composed of ethylene terephthalate and isophthalic acid 1 to 4.5.
Ethylene oxide adduct of mol% and bisphenol A 2
Polyester (B) copolymerized with ~ 7 mol% is eccentrically bonded, the shrinkage ratio at free heat treatment at 170 ° C is 15% or less, and the heat treatment at 170 ° C causes relaxation. The number of spiral crimps is 50/25 mm or more,
When producing a composite fiber having an elongation of 25% or less and a strength of 6.5 g / d or more, the stretching is performed in two stages, and the first stage is stretched at a draw ratio of 70 to 95% of the total draw ratio. While passing through the heating steam processor, the heating steam temperature 130 to 17
A gist of the present invention is a method for producing a latently crimpable polyester conjugate fiber, which comprises performing a second stage drawing at 0 ° C for a residence time of 0.5 seconds or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The conjugate fiber produced by the present invention is one in which polyester (A) and polyester (B) are eccentrically joined, and polyethylene terephthalate (PET) is preferably used as polyester (A). If the effect is not impaired, PET may be copolymerized with components such as isophthalic acid (IPA), 1,4-butanediol, 1,6-hexanediol, diethylene glycol and polyethylene glycol.

On the other hand, as the polyester (B), ethylene terephthalate units are mainly used, and IPA is 1 to 4.5.
It is necessary to copolymerize 2% to 7% by mol of BAEO with mol%. If the copolymerization ratio of IPA is less than 1 mol%, the resulting composite fiber will have insufficient latent crimp performance, and if it exceeds 4.5 mol%, the melting point of the polymer will decrease.
It becomes impossible to obtain a composite fiber in which the polyesters (A) and (B) are eccentrically joined.

When the amount of BAEO copolymerized is less than 2 mol%, the resulting composite fiber has insufficient latent crimp performance, and when the composite fiber is used as a nonwoven fabric or spun yarn, the elongation rate and elongation recovery are obtained. The rate is small and the expansion / contraction performance is poor.
On the other hand, when it exceeds 7 mol%, the melting point of the polymer is lowered and the strength of the obtained fiber is lowered. BAEO contains 2 moles of ethylene oxide per 1 mole of bisphenol A.
It is preferable to add 10 mol, more preferably 2 to
5 moles are added.

In the present invention, the intrinsic viscosities of the polyesters (A) and (B) constituting the conjugate fiber are not particularly limited, but from the viewpoint of smooth melt spinning, the polyester (A) is 0.50 to 0.70. , Polyester (B) is 0.55 ~
0.75 is preferable. Then, in order to obtain a conjugate fiber which is excellent in spinning stability and in which crimps are sufficiently expressed in the subsequent step, it is preferable that the intrinsic viscosity difference between the two kinds of polymers is 0.25 or less. If the difference in viscosity is more than 0.25, the bending of the yarn just below the spinneret becomes large, and the spinning tends to become unstable.

The composite fibers in which the polyesters (A) and (B) are joined eccentrically include those having a side-by-side structure or an eccentric core-sheath structure. Examples include irregular shapes such as a triangular cross section or hollow cross sections.

Next, a method for producing the conjugate fiber of the present invention, which comprises the polyesters (A) and (B) as described above, will be described. First, the polyesters (A) and (B) are used to spin a conjugate fiber having a side-by-side or eccentric core-sheath structure in a cross-sectional shape by an ordinary conjugate spinning device. In addition,
During spinning, the polymer may contain stabilizers, fluorescent agents, pigments, reinforcing agents and the like. Then, the obtained undrawn yarn is drawn in the first stage at a draw ratio of 70 to 95% of TDR, and subsequently, while passing through the heating steam processor, the heating steam temperature is 130 to 170 ° C. and the residence time is 0.5. It is necessary to perform the second stage stretching for not less than 2 seconds.

When the first stage drawing is carried out at a draw ratio of more than 95% of TDR, the first step draw ratio is too high, so that yarn breakage occurs and the operability is remarkably deteriorated. It will be lowered. If the first stage is drawn at a draw ratio of less than 70% of TDR, the draw ratio of the second stage becomes too high, so that fusion occurs between the single yarns in the stage of heating steam treatment.

In the above stretching, TDR is 3.7.
It is preferably double or more, and more preferably 4.0 or more. The stretching ratio of the first stage stretching is preferably 2.6
The stretch ratio in the second stage stretching is preferably 1.05 to 1.5 times.

The second stage drawing is carried out while heating with steam in a heating steam processor, but it is necessary to set the temperature of the heated steam ejected from the processor to 130 to 170 ° C.
More preferably, the temperature is 140 to 150 ° C. Then, it is necessary to set the time for heating the yarn by allowing the yarn to stay in the heating steam processor to be 0.5 seconds or more. If the temperature of the steam in the heating steam processor is less than 130 ° C., the yarn is not uniformly and sufficiently heated, so that the obtained fiber has high elongation and low strength. If the temperature exceeds 170 ° C, the fibers will fuse together,
Thread breaks occur.

The time required for heat treatment by allowing the yarn to stay in the heated steam processor must be 0.5 seconds or more, preferably 1 to 3 seconds. If the residence time is less than 0.5 seconds, heat transfer to the yarn will be insufficient and sufficient heat treatment will not be possible. The upper limit of the residence time is not particularly limited, but is about 3 seconds.

The composite fiber obtained by the production method of the present invention is
When used as short fibers to obtain spun yarn or nonwoven fabric,
In order to improve the passability in the spinning process and the card process, it is preferable to apply a mechanical crimp of 8 to 18 pieces / 25 mm, and further 10 to 16 pieces / 25 mm after the second stage drawing. When the number of mechanical crimps is less than 8 pieces / 25 mm, the effect of improving the passability in the above steps is small,
When it exceeds 18 pieces / 25 mm, it takes time and cost to apply the mechanical crimp, which is not preferable. The method for applying the mechanical crimp is not particularly limited, and examples thereof include a method using a press-type crimping device.

By carrying out such stretching and heat treatment, the strength is 6.5 g / d or more, the elongation is 25% or less, and the shrinkage ratio in the free shrink heat treatment at 170 ° C. is 15% or less. Moreover, a latent crimpable conjugate fiber having a number of spiral crimps of 50/25 mm or more developed by relaxation heat treatment at 170 ° C. can be obtained.

When the strength is less than 6.5 g / d and the elongation is more than 25%, such a composite fiber cannot be speeded up in the spinning process and is strong in frictional force. A cloth having crimp performance cannot be obtained. 170 ° C
When the shrinkage rate in free shrink heat treatment in
The cloth obtained by using this composite fiber has a hard texture. When the number of spiral crimps of the composite fiber is less than 50/25 mm, the obtained fabric has poor stretchability.

In the present invention, the fineness of the undrawn yarn is not particularly limited, and in the case of obtaining long fibers, the fineness is 30 to
In order to obtain a 200 denier yarn and to obtain spun yarn and short fibers for a nonwoven fabric, it is preferable to bundle the yarn into a yarn bundle of 1 to 1 million denier and then draw. The first-stage stretching may be dry or wet, but wet stretching using a hot water bath or the like is preferable because the stretching point is easily fixed.

Further, when the conjugate fiber obtained by the method of the present invention is used as a spun yarn in the spinning process, spiral crimp is developed by heat treatment during dyeing, and when a nonwoven fabric is produced, a card web is used. Spiral crimps develop during heat treatment.

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. While passing the undrawn yarn yarn bundle Y through the hot water bath 6 between the feed roller 1 and the first draw roller 2, the first stage drawing is performed. Subsequently, the undrawn yarn yarn bundle Y is drawn between the first draw roller 2 and the second draw roller 3 while passing through the inside of the heated steam processor 5, and the second stage drawing is performed. Then, the drawn yarn bundle is taken up by the take-up roller 4. At this time, if the take-up roller 4 is in the range of 120 to 170 as long as the effect of the present invention is not impaired.
The relaxation heat treatment may be performed with the second draw roller 3 by heating to about ° C. Also, when mechanical crimping is applied,
After being taken up by the take-up roller 4, mechanical crimping is applied by a push-type crimping device or the like.

[0023]

Next, the present invention will be specifically described with reference to examples. In addition, the measuring method of various characteristic values in an Example is as follows. (1) Intrinsic viscosity [η] It was measured at a temperature of 20 ° C using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (2) Fineness Measured by the method of JIS L-1005 7-5-1A. (3) Strength and elongation Measured by the method of JIS L-1015 7-7. (4) Number of crimps (number of spiral crimps) After heat-treating the obtained fibers at 170 ° C. for 5 minutes in a freely shrinkable state (no load), JIS L-1015 7-21-1
The number of spiral crimps developed in the fiber was measured by the method described in 1. (5) Free shrinkage: According to JIS L-1015 7-15, 300 per 1 denier
It was measured by applying a load of mg. (6) Spun spinning strength A 40-spun spun yarn was obtained, the resulting spun yarn was cut into 40 cm, and the tenacity was measured with a tensile tester at a speed of 20 cm / min to measure the tenacity. (7) Nonwoven fabric strength The obtained fiber is made into a card web having a basis weight of 50 g / m ² ,
A nonwoven fabric was obtained by treating at 170 ° C. for 1 minute. Weft 25
mm, length 150 mm, and measured by the method of JIS L-1096.

Example 1 As polyester (A), PET having an intrinsic viscosity of 0.67, and as polyester (B), 4 mol% of IPA and B were added to PET.
Using a copolymerized PET having an intrinsic viscosity of 0.70 in which 3 mol% of AEO (ethylene oxide 2 mol adduct) was copolymerized, polyester (A) and (B) chips were dried under reduced pressure by a conventional method, and then an ordinary composite spinning device was used. Was used for melt spinning. At this time, using a spinneret having 344 pores with a round cross section of 0.45 mm in diameter and having two types of polyester compounded side by side (weight ratio 1: 1), a spinning temperature of 29
Composite spinning was performed at 0 ° C. and a total discharge rate of 230 g / min. The spun yarn was cooled with air and then taken off at a speed of 1000 m / min to obtain an undrawn yarn. Next, the obtained yarns were bundled into a tow of 100,000 denier, and two-stage drawing was performed using the drawing device shown in FIG. First, the temperature of the feed roller is 70 ° C, the temperature of the hot water bath is 60 ° C, the first stage stretching is performed between the feed roller and the first draw roller, and the temperature of the first draw roller is 85 ° C.
℃ and heated steam at 145 ℃ for 1.5 seconds in the steam processor, and the first draw roller and the second draw roller (60
C.) and the second drawing was performed. Subsequently, the temperature of the take-up roller was taken out at 170 ° C., and then 12 crimps / 25 mm of mechanical crimps were applied by a press-type crimping device and cut into 51 mm to obtain short fibers. At this time, TDR was 4.02 times, the first stage draw ratio was 3.72 times (92.6% of TDR), and the second stage draw ratio was 1.08 times. Table 2 shows the physical properties of the obtained fiber, the tenacity of the spun yarn obtained by spinning the fiber at a spindle speed of 15,000 rpm, and the tenacity of the non-woven fabric obtained from the fiber.

Examples 2 to 3 and Comparative Examples 1 to 8 Copolymer molar ratio of polyester (B) of IPA and BAEO, TDR, draw ratio of the first step (ratio when TDR is 100), second step. A latent crimpable conjugate fiber was produced in the same manner as in Example 1 except that the draw ratio, the temperature of the heated steam in the heated steam processor and the residence time were variously changed as shown in Table 1. The physical properties of the obtained fiber, the number of revolutions of the fiber was 15,000 rpm (13500 rpm for Comparative Example 2 and 14 for Comparative Example 3).
Table 2 shows the tenacity of the spun yarn obtained by spinning at 000 rpm) and the tenacity of the non-woven fabric obtained from this fiber.

[0026]

[Table 1]

[0027]

[Table 2]

As is clear from Table 2, the fibers obtained in Examples 1 to 3 have excellent crimp-developing performance, low elongation and high tenacity. Both the spun yarn and the non-woven fabric had high strength. On the other hand, Comparative Example 1
In Comparative Example 2, the polyester (B) was not copolymerized with BAEO, and the polyester (B) was not copolymerized with IPA. Both the degree property and the crimp development performance were inferior. Further, in Comparative Example 3, since the copolymerization amount of BAEO and IPA of the polyester (B) was too large, the obtained fiber had high elongation and low strength. In Comparative Example 4, the temperature of the heating steam processor was too low, and in Comparative Example 6, the residence time in the heating steam processor was too short, so that heat treatment could not be sufficiently performed, and the obtained fiber was The elongation was high and the strength was low. Also,
In Comparative Example 5, since the temperature of the heating steam processor was too high,
In Comparative Example 8, since the draw ratio of the second step was too high, when the second step of drawing was performed with the heating steam treatment device, fusion of the single yarn occurred and the drawn yarn could not be obtained. In Comparative Example 7, since the draw ratio of the first step was too high, roller winding of the yarn bundle occurred due to yarn breakage in the first step, and a drawn yarn could not be obtained.

[0029]

EFFECTS OF THE INVENTION According to the present invention, short fibers can be spun at a high speed, a spiral crimp is developed by heat treatment, and a friction-resistant cloth or non-woven fabric having good stretchability is obtained. It is possible to easily produce the latently crimpable polyester conjugate fiber.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Feed Roller 2 First Draw Roller 3 Second Draw Roller 4 Take-up Roller 5 Heated Steam Processor 6 Hot Water Bath

Claims (2)

[Claims] 1. A polyester (A) mainly composed of ethylene terephthalate and an polyester (B) obtained by copolymerizing 1 to 4.5 mol% of isophthalic acid and 2 to 7 mol% of an ethylene oxide adduct of bisphenol A are eccentrically joined. And the shrinkage rate in free shrink heat treatment at 170 ° C is 15%.
In the production of a composite fiber having a number of spiral crimps of 50/25 mm or more, an elongation of 25% or less, and a strength of 6.5 g / d or more, which are not more than 170 ° C. The total draw ratio is 70-95.
%, The second stage is stretched at a heating steam temperature of 130 to 170 ° C and a residence time of 0.5 seconds or more while passing through the heating steam processor. Method for producing crimpable polyester conjugate fiber. 2. 8 to 18 pieces / 25 after the second stage drawing
The method for producing a latently crimpable polyester conjugate fiber according to claim 1, wherein a mechanical crimp of mm is applied.