JPH11279827A - Modified cross-sectional yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a synthetic fiber yarn with modified cross section usable as a warp for woven fabrics or in tricots by setting the variance of modification degree M-value in the yarn expressed with CV-value at a specified level or greater. SOLUTION: This synthetic fiber yarn with modified cross section is obtained by heating and melting a resin such as of nylon 6, nylon 66 or polyethylene terephthalate, delivering the resultant molten polymer through a spinneret, followed by cooling and solidification to form a yarn which is then oiled, drawn and wound. The synthetic fiber yarn thus obtained has such a character that the variance of modification degree M-value in the yarn expressed with CV- value is >=7%, but pref. <=20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified cross-section yarn. More specifically, the present invention relates to a synthetic fiber yarn having a deformed cross section used for warp and tricot of a woven fabric.

[0002]

2. Description of the Related Art Japanese Patent Publication No. Sho 64-1570 discloses a method in which yarns having substantially the same single fiber fineness and different cross-sectional shapes are aligned and used for temporary twisting.

[0003]

Synthetic fibers having a deformed cross section are designed so that the degree of cross-sectional deformation within and between the yarns is as uniform as possible. However, the degree of cross-sectional deformation is not uniform between the yarns and in the warp direction of the yarn due to the viscosity of the polymer used as the raw material, the design accuracy of the die discharge hole and the change over time, the fluctuation of the spinning temperature, the fluctuation of the cooling state, etc. Difficult to maintain. When synthetic fibers with an uneven degree of cross-sectional deformation are used for warp or tricot of a woven fabric, and a plurality of raw yarns with a high degree of deformation and a plurality of yarns with a low degree of deformation are respectively lined up, they become more noticeable as warping defects and become woven or tricot. May be C-response (nonstandard rejected product), resulting in product loss.

Accordingly, an object of the present invention is to provide a process for spinning a synthetic fiber, which is caused by the viscosity of a polymer serving as a raw material, the design accuracy and time-dependent change of a spinneret discharge hole, a variation in spinning temperature, and a variation in a cooling state. It is an object of the present invention to provide a cross-sectionally deformed yarn capable of forming a woven fabric and a tricot of stable quality even when the degree of cross-sectional deformation varies between the yarns and the warp direction of the yarn.

[0005]

In order to achieve the above-mentioned object, a modified cross-section yarn of the present invention has the following constitution. That is, it is a synthetic fiber yarn having a deformed cross section, wherein the variation in the degree of deformation M within the yarn is 7% or more expressed as a CV value.

In the modified cross-section yarn of the present invention, the variation of the degree of deformation M in the yarn is represented by a CV value of 7% or more. If the variation of the M value within the yarn is less than 7% as represented by the CV value, there is a problem that the gloss difference due to the M value difference between the yarns becomes apparent.

Here, the CV of the degree of deformation M in the yarn
The value is determined as follows, where M _{AV is} the average value of the degree of deformation M of each single fiber in _the yarn, and σ is the standard deviation of the degree of deformation M of each single fiber in _the yarn.

[0008] CV value of the degree of deformation M in the yarn = σ / M _AV

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As synthetic fibers used in the present invention, various thermoplastic resins such as polyamide, polyester and copolymers thereof are preferable. Preferably, the thermoplastic resin is nylon 6, nylon 66, polyethylene or the like. It can be obtained by using terephthalate in a known manner, for example, by heating and melting these resins, discharging from a die, cooling and solidifying, applying an oil agent, stretching and winding.

[0010] From the viewpoint of reducing spun yarn breakage and fluff, the modified cross-section yarn preferably has a fineness variation of a single fiber of not more than 20% as represented by a CV value.

Here, the CV value of the single fiber fineness can be obtained as follows when the average value of each single fiber fineness in _the yarn is d _{AV and} the standard deviation of each single fiber fineness in _the yarn is σ. .

CV value of single fiber fineness = σ / d _AV Next, an example of the modified cross-section yarn of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the cross-sectional shape of a modified cross-section yarn. In each variation section, 1 if the diameter circumscribed circle to its diameter and D ₂ in D _1, 2 are inscribed circle, deformation degree M values, as follows, circumscribing the cross-section diameter D ₁ And the ratio of the inscribed circle diameter D ₂ of the cross section.

Deformation M value = Diameter of circumscribed circle D ₁ / Diameter of inscribed circle D ₂ FIG. 2 shows a case where a conventional triangular cross-section yarn forms one yarn with 13 yarns. FIG. 3 shows an example in which one yarn is formed from 13 single fibers with the triangular cross-section yarn of the present invention. In FIG. 2, reference numerals 3 to 15 denote individual fibers of the conventional triangular cross-section yarn, and the variation of the M value within the yarn is usually represented by a CV value of 6%.
Within. Normally, the average value of the M value between the yarns is a maximum of 3% expressed as a CV value due to the viscosity of the polymer as a raw material, the design accuracy and the change over time of the spinneret discharge hole, the variation of the spinning temperature, and the variation of the cooling state. However, in the conventional case, the difference in gloss due to the variation in the M value between the yarns is larger than the difference in gloss due to the variation in the M value between the single fibers. The resulting vertical streak tended to be a defect.

On the other hand, in FIG. 3, reference numerals 16 to 28 denote individual fibers of the triangular cross-section yarn of the present invention, and the variation of the M value in the yarn is 13% in terms of CV value. In this case, since the gloss difference due to the M value variation between the single fibers is large, even if the average value of the M values between the yarns varies, the gloss difference does not become apparent.

FIG. 4 shows an example of a base discharge hole used in the present invention. In the figure, 29 is the hole depth L of the discharge hole, 30 is the slit width a of the discharge hole, 31 is the slit length b of the discharge hole, 32 is the inscribed circle R ₁ of the discharge hole, 3
3 is a representation of the circumscribed circle R ₂ of the discharge holes, respectively.

Next, an example of the method for producing a modified cross-section yarn of the present invention will be described. When the thermoplastic resin is heated and melted and spun, the back pressure .DELTA.P of the die is expressed by the formula (1) in the case of a Y-shaped cross section.

ΔP = K ₁ × (L / a) × [( ² × Q) / (a ² × bxρxH)] ⁿ (1) Here, K ₁ is a constant determined by the spinning temperature. When ゜ C, K ₁ = 0.298. Q is the amount of polymer discharged per cap, ρ is the polymer density, H is the number of holes in the cap, n is an index determined experimentally, and is 0.48 for a Y-shaped cross section.

The M value of the cross-sectional deformation of the melt-spun yarn is proportional to R ₂ / R ₁ . Accordingly, when the base slit length b is increased, R ₂ is also increased, and as a result, the M value is increased. In this way, the thermoplastic resin is heated and melted by the spinneret having the discharge holes with different slit lengths and spun, whereby the M value variation in the yarn is expressed by the CV value, and a deformed cross-section yarn of 7% or more can be obtained. You can. However, at this time, since the fineness of the single fiber varies greatly, there is a tendency that spun yarn breakage or fluff occurs. In order to prevent this, the above formula (1) is used to make the back pressure of the base discharge hole the same.
When the hole depth L is long, it is preferable to adjust L long, and when b is short, it is preferable to adjust L short. By adjusting the hole depth of the discharge holes in this way, it is possible to easily suppress the variation in fineness between single fibers to be within 20% as represented by a CV value.

[0020]

The present invention will be described below in detail with reference to examples.

In the examples, when the deformed cross-section yarn was a tricot, the grade was evaluated visually by judging the degree of warping and evaluated in the following three grades.

W1: good product W2: lower limit of quality W3: unusable [Examples 1 and 2] A polyamide chip having a relative viscosity of 2.60 was heated and melted at a spinning temperature of 260 ° C., and a die discharge hole slit was prepared based on the method of the present invention. Fix width a to 0.10mm,
Using a die having 6 holes with a discharge length b of 0.41 mm and 7 holes with a discharge length b of 0.48 mm, spinning is performed with a die having a die depth L of 0.40 mm and a total fineness. A 40D, 13-filament Y-shaped cross-section yarn was obtained (Example 1).

The shape of the base slit is the same as that of the first embodiment.
0.40m hole depth corresponding to slit length 0.41mm
m, hole depth corresponding to slit length 0.48 mm 0.6
The yarn was spun with a die having a diameter of 5 mm to obtain a Y-shaped cross-section yarn having a total fineness of 40D and 13 filaments (Example 2).

In each case, the average value between the yarns of the degree of deformation M is 1.60. In both Examples 1 and 2, the M value variation in the yarn was as large as 8% as expressed by the CV value, and the M value variation between the yarns was as large as 3% as the CV value. The variation in the difference in gloss between yarns measured by a gloss meter after winding on a plane is expressed as a CV value and is as small as 10%.
The quality when used in a tricot was as good as W1. In addition, the variation in single fiber fineness is expressed as a CV value of 10%.
% In Example 2, the spun yarn breakage was extremely good, and was as small as about 1/3 of the spun yarn breakage in Example 1.

[Comparative Example 1] A polyamide chip having a relative viscosity of 2.60 was melted by heating at a spinning temperature of 260 ° C, and the die discharge hole slit width a was 0.10 mm and the slit length b was 0.41.
The yarn was spun with a die having 13 discharge holes having a diameter of 0.4 mm and a depth L of 0.40 mm to obtain a Y-shaped cross-section yarn having a total fineness of 40D and 13 filaments (Comparative Example 1).

In this case, the variation in the M value within the yarn was 5% as represented by the CV value, but the variation in the M value between the yarns was as large as 3% as represented by the CV value. The difference in gloss between the yarns measured by a gloss meter was also expressed as a CV value of 3%, which was as large as 3% when used for tricots, which was a rejected product level.

[0027]

[Table 1]

[0028]

According to the present invention, the following excellent effects can be obtained by adopting the above structure.

(A) Even when the variation in the degree of cross-sectional deformation M between yarns is large, good quality can be obtained when used in a tricot.

(B) Even if the M value variation between the single fibers is large, it does not adversely affect the yarn breakage.

[Brief description of the drawings]

FIG. 1 is an example of a cross-sectional shape of a modified cross-section yarn.

FIG. 2 is an example of a cross-sectional shape of a conventional triangular cross-section yarn.

FIG. 3 is an example of a cross-sectional shape of a triangular cross-section yarn of the present invention.

FIG. 4 is an example of a die discharge hole used in the present invention.

[Explanation of symbols]

1: circumscribed circle 2: inscribed circle 3 to 15: each single fiber in conventional triangular cross section yarn 16 to 28: each single fiber in triangular cross section yarn of the present invention 29: hole depth L of discharge hole 30: slit width a of the discharge hole a 31: slit length b of the discharge hole 32: inscribed circle R ₁ 33 of the discharge hole 33: circumscribed circle R _{2 of the} discharge hole

Claims (2)

[Claims] 1. A synthetic fiber yarn having a deformed cross section,
A deformed cross-section yarn characterized in that a variation in the degree of deformation M within the yarn is 7% or more expressed as a CV value. 2. The fineness variation of a single fiber is represented by a CV value of 2
The modified cross-section yarn according to claim 1, wherein the yarn content is 0% or less.