JPH09170128A - Cellulose acetate multifilament yarn having each specific cross section and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acetate multifilament yarn reduces in the irregularity of the cross-sectional shape of each acetate filament, having the cross-sectional shape not having been obtained by conventional methods improved in spinnerets, and having original luster and touch. SOLUTION: This cellulose acetate multifilament yarn wherein the single filaments has each a special I-shaped cross section and further each the length ratio(L1 ) of the cross section in the longitudinal direction, the length ratio (L2 ) in the latitudinal direction and the length ratio (L3 ) in the longitudinal direction and in the latitudinal direction which simultaneously satisfy the below-described relations occupy >=60% of the whole single filaments. The ratio (L1 ) of (b) the whole length in the longitudinal direction to (a) the length of the central part is 1.5-2.5. The ratio (L2 ) of (d) the maximum width of both the terminal thick parts to the width (c) of the central thin part is 1.5-2.5. The ratio (L3 ) of (d) the whole width in the longitudinal direction to (c) the width of the central thin part is 2.5-8.0.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cellulose acetate multifilament yarn having a special cross section and a method for producing the same. More specifically, by adding polyoxyalkylene glycol to the acetate spinning dope, using a spinneret having a rectangular spinning hole, and by dry-spinning, it has a special cross-sectional shape that has never been seen, and has excellent gloss and TECHNICAL FIELD The present invention relates to a textured cellulose acetate multifilament yarn and a method for producing the same.

[0002]

2. Description of the Related Art Cellulose acetate (hereinafter, also referred to as "acetate") fibers have excellent color-forming properties and dry texture, and exhibit excellent properties as a material for fashion. However, in recent years, consumer needs for textiles have become more sophisticated and diversified,
Further improvements and improvements are desired.

Regarding the cross-sectional shape of the yarn, in the case of acetate fiber, a raw material for spinning, which is a raw material acetate flakes dissolved in a solvent such as acetone or methylene chloride, is discharged from a spinneret to evaporate the solvent in the spinning cylinder. That is, since it is dry spinning, even if the spinning dope is discharged from the spinneret having circular spinning holes, its cross section has many irregularities at the stage of being wound up as a thread. This is because when the yarn is dried in the spinning tube, the outer part of the yarn is first dried to form a skin, and the solvent inside is evaporated and removed. It is believed that the outer skin partially penetrates into the inside of the thread and creates irregularities.

Conventionally, a method of devising a spinneret has been adopted as a means for changing the cross-sectional shape of acetate fibers.

For example, Japanese Examined Patent Publication No. 37-7917 discloses an attempt to discharge the spinning dope from a spinneret having triangular or square spinning holes. In addition, Japanese Unexamined Patent Publication
In Japanese Patent Publication No. 0-134012, a Y-shaped cross-section acetate fiber is obtained by forming a plurality of spinning holes having a specific cross-sectional shape at specific intervals. Furthermore, JP-A-3-59105
In the publication, an attempt was made to obtain an acetate fiber having a hollow cross section by using a double tube type spinneret in which an inner tube is discharged from an end surface of an outer spinneret and an outer diameter and a length of a discharge portion are adjusted to specific ranges. Has been.

However, in these prior arts, it is not possible to change the dry state of the solvent, and it is difficult to form a yarn having the same number of protrusions and depressions, and a yarn whose cross-sectional shape deviates greatly from the intended shape is mixed. Was.

[0007]

DISCLOSURE OF THE INVENTION The present invention has a cross-sectional shape which has not been obtained by the method of improving the spinneret by reducing the unevenness of the cross-sectional shape of the acetate fiber, and has a unique gloss and texture. It aims at providing the acetate fiber which has.

[0008]

According to the present invention, a single fiber has an I-shaped cross section, and the length ratio (L ₁ ) in the longitudinal direction of the cross section, the length ratio (L ₂ ) in the width direction, and Cellulose acetate mulch having a special cross-section, characterized in that the number of monofilaments satisfying the following relationship at the same time in the length ratio (L ₃ ) in the longitudinal direction and the width direction accounts for 60% or more of the total number of monofilaments. It is a filament thread. (L ₁ ) Length of central detail (a) and total length in the longitudinal direction (b)
Ratio: b / a = 1.5 to 2.5 (L ₂ ) The ratio of the width (c) of the central detail to the width (d) of the larger one of the thick portions at both ends d / c = 1. 5 to 2.5 (L ₃ ) Ratio of width (c) of central details to total length (b) in longitudinal direction = b / c = 2.5 to 8.0 The present invention also relates to cellulose acetate flakes and the cellulose. 5-40% by weight based on acetate flakes
Special cross-section characterized by discharging a spinning dope containing polyoxyalkylene glycol of (1) and a solvent capable of dissolving the cellulose acetate flakes and polyoxyalkylene glycol from a spinneret having a rectangular spinning hole, and performing dry spinning. A method for producing a cellulose acetate multifilament yarn having

The cellulose acetate to which the present invention is applied is one in which 1 to 3 hydroxyl groups on average out of 3 hydroxyl groups present in the repeating unit of cellulose are acetic acid esters, and particularly 1.9 to 1 average. It is preferable that 2.8 are esterified (acetylation degree 47 to 60%).

The acetate multifilament yarn of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged schematic view of a cross-sectional shape of a single fiber constituting an acetate multifilament yarn having a special cross section of the present invention. FIG. 2 is a cross-sectional view of an acetate multifilament yarn having a special cross section of the present invention, and FIG. 3 is a cross-sectional view of a conventional acetate multifilament yarn using the same spinneret as in FIG. Here, A and C are thick portions at both ends of the I-shaped cross section, and B is a central detail.

The monofilament cross section of the acetate multifilament yarn of the present invention is an I-shaped cross section consisting of two thick parts (A and C) at both ends and a central detail (B). The ratio (b / a) of the length a of the detail to the total length b in the longitudinal direction is 1.5 to 2.5, and the ratio of the width c of the central detail to the width d of the larger one of the thick portions at both ends. It is necessary that (d / c) is 1.5 to 2.5, and the ratio (b / c) of the width c of the central detail to the total length b in the longitudinal direction is 2.5 to 8.0.

The ratio (b / a) of the length a of the central detail to the total length b in the longitudinal direction and the ratio (d / c) of the width c of the central detail to the larger width d of the thick portions at both ends, If the ratio (b / c) of the width c of the central detail to the total length b in the longitudinal direction does not satisfy the above value at the same time, an acetate multifilament yarn having a unique luster and texture that has never been obtained cannot be obtained.

In the acetate multifilament yarn of the present invention, it is necessary that the number of single fibers having the above-mentioned cross-sectional shape is 60% or more, preferably 70% or more of the total number of single fibers. If this ratio is less than 60%, the gloss and feel of the fabric will not be improved.

In general, acetate fibers are obtained by dissolving acetate flakes in a solvent such as acetone or methylene chloride to prepare a spinning dope, discharging this from a spinneret having circular spinning holes, and performing dry spinning. In this dry spinning, the spinning stock solution is discharged from the spinneret and the solvent evaporates and hardens at the same time.At that time, the outer side first hardens to form the skin, which is the solvent inside. Partly goes inside when it comes out,
The unevenness is completed. When an ordinary spinning dope is used, this degree is large, and the depth of the recess becomes an uneven shape with a depth of 6 to 10 μm.

The acetate multifilament yarn of the present invention is obtained by adding polyoxyalkylene glycol to a spinning dope, discharging the spinning dope from a spinneret having a rectangular spinning hole, and performing dry spinning.

Here, how the cross-sectional shape becomes I-shaped and uniform by the addition of polyoxyalkylene glycol is considered as follows.

That is, in the case of acetate fibers, the spinning solution is discharged from the spinneret and the solvent evaporates and is cured at the same time. At that time, the outer side first hardens,
It forms an epidermis, which partially penetrates inside when the solvent inside escapes, creating irregularities. Immediately after the spinning dope is discharged from the spinneret having a rectangular spinning hole,
Although the cross-sectional shape is rectangular, it is considered that after the skin is formed, the above mechanism causes two of the long sides of the four sides of the rectangle to enter the inside to form an I-shape. However, when an ordinary spinning dope is used, this deformation is large, the short side of the rectangle is also dented, and the cross-sectional shape is largely broken. On the other hand, when polyoxyalkylene glycol is added, the formation of the epidermis is delayed, and the solvent in the interior is removed more before hardening. Therefore, the degree of penetration of the epidermis into the inside of the yarn is reduced and the change in shape is suppressed to a low level. Therefore, it is considered that a cross section holding the I-shape is formed.

As the polyoxyalkylene glycol contained in the above-mentioned acetate, a polymer composed of ethylene oxide and / or propylene oxide, or a mixture thereof can be used. In particular,
Polyethylene glycol, polypropylene glycol,
Examples thereof include ethylene oxide / propylene oxide random copolymers. The molecular weight is not particularly limited, but is preferably 25, from the viewpoint of compatibility with the spinning dope.
000 or less, more preferably 20,000 or less. When it exceeds 25,000, the compatibility with the spinning dope becomes poor and the spinning tone tends to become poor.

The amount of polyoxyalkylene glycol added is 5 to 40% by weight, preferably 10% by weight, based on acetate.
３０30% by weight. If it is less than 5% by weight, the special cross-sectional shape of the present invention cannot be obtained. On the other hand, if it exceeds 40% by weight, the viscosity of the spinning dope is remarkably reduced, which is a cause of yarn breakage during dry spinning, which is not preferable.

The spinneret used in the present invention is required to have a rectangular shape. The area of the rectangle and the number of holes are not particularly limited, but from the viewpoint of spinning tone, the draft ratio, that is, the linear discharge velocity Vj (m / min) of the spinning dope from the spinneret and the spinning take-up velocity Vf (m
/ Min) ratio Vf / Vj is preferably set to 1.1 to 1.4. Specifically, the length of one side of the rectangular spinning hole is preferably 240 μm or less, 30 to 10
It is particularly preferred that the thickness be 0 μm. Further, the ratio of the length of the short side to the length of the long side of the rectangle is preferably 1.4 to 4.0, and particularly preferably 1.8 to 3.6. The spinning take-up speed is preferably 650 m / min or more.

Particularly, in the present invention, as spinning conditions for obtaining a special cross section, it is considered as follows that high-speed production can be maintained with a spinning winding speed of 650 m / min or more. When a normal spinning dope is used, it is considered that the spinning tension is applied to a short portion just below the spinneret because the epidermis is quickly formed in the spinning tube. This means that a large force is applied in the vertical direction when the skin is formed, and further, the above-mentioned lateral force, that is, the degree of entering the inside is also large, so that the strain becomes large, and the cross-section is likely to be distorted and uneven. Therefore, in order to obtain a uniform cross section, it is necessary to reduce the spinning speed and tension to suppress the strain. On the other hand, when polyoxyalkylene glycol is added, the skin formation is delayed and the tension is applied to a long portion under the die, so that the force is dispersed and lowered. Furthermore, since the degree of penetration of the epidermis into the inside is also small, it is thought that distortion will be small and a uniform cross section will be obtained, so high spinning speed is possible,
It leads to high production efficiency.

In the present invention, when dry spinning is performed using an acetate spinning dope containing polyoxyalkylene glycol, the temperature of the spinning dope discharged from the spinneret is the acetate spinning dope without addition of polyoxyalkylene glycol. The temperature may be set to substantially the same level as the temperature at which the temperature is set, but it is preferably slightly lower, that is, 62 to 5
It is preferable to set the temperature to 5 ° C. because the irregularity specified in the present invention can be enhanced.

To add the polyoxyalkylene glycol to the acetate spinning dope, for example, a method in which cellulose acetate is dissolved in a solvent such as acetone or methylene chloride, that is, when the acetate spinning dope is prepared, or polyoxyalkylene is used. A method may be mentioned in which glycol is heated and melted, and the glycol is fed to a spinning machine while being mixed with an acetate spinning stock solution in a ratio so that a desired content is obtained, and then dry spinning is performed.

Although the added polyoxyalkylene glycol is eluted during the scouring after forming the cloth, the cross-sectional shape of the fiber does not change due to this.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

Various evaluations in the examples were measured as follows.

Cross-section rate As shown in FIG. 1, it has an I-shape, and the ratio of the length of the central detail to the total length in the longitudinal direction is 1.5 to 2.5 in the longitudinal direction of the cross section, and The ratio of the number of single fibers in the acetate multifilament yarn in which the ratio of the width of the details and the width of both ends is 1.5 to 2.5, and the ratio of the width of the central details to the overall length in the longitudinal direction is 2.5 to 8.0. Was expressed as a percentage.

Gloss Using the obtained acetate multifilament yarn, a tubular knit was produced, and the gloss after visually removing the oil agent and the polyoxyalkylene glycol by scouring was evaluated. In addition, Comparative Example 6 was judged to be standard (good), and those better than this were judged to be extremely good.

[0029] The texture gloss evaluation tubular knitted fabric by the same process as was evaluated by touch. It should be noted that Comparative Example 6 was judged as a standard (good), and one having a good bulkiness by dry touch was judged to be extremely good.

[Examples 1 to 10 and Comparative Examples 1 to 4] Cellulose acetate flakes having an average degree of acetylation of 54.7% and polyethylene glycol (PEG) at a ratio shown in Table 1 were 31 parts by weight in total, and 68 parts by weight of acetone. Parts and 1 part by weight of water were mixed and defoamed to prepare a uniform spinning dope.

This spinning dope was spun in a dry spinning apparatus under the conditions shown in Table 1 by using a spinneret with 20 holes and a rectangle having a short side of 40 μm and a long side of 80 μm. While adjusting the temperature to 59 ° C., dry spinning was carried out at a desired spinning winding speed to obtain 100 denier / 20 filament acetate multifilaments. Table 1 shows the results.

Comparative Examples 5 to 6 24 parts by weight of cellulose acetate flakes having an average degree of acetylation of 54.7%, 75 parts by weight of acetone and 1 part by weight of water were mixed and defoamed to prepare a uniform spinning dope. .

Using a spinning spinneret having 20 rectangular spinning holes each having a short side of 40 μm and a long side of 80 μm, this spinning dope was heated in a dry spinning apparatus under the conditions shown in Table 1 to obtain a spinning dope temperature. Was adjusted to 65 ° C., and dry spinning was performed under the same dry spinning conditions as in Example 1 to obtain an acetate multifilament of 100 denier / 20 filaments. Table 1 shows the results.

2 and 3 are photomicrographs (magnification 400 times) of the cross-sectional shapes of the acetate multifilament yarns obtained in Example 3 and Comparative Example 5, respectively.

[0035]

[Table 1]

[0036]

EFFECTS OF THE INVENTION According to the present invention, an acetate multifilament yarn having a uniform and special cross-section which has never been obtained can be obtained, and an acetate fabric having excellent gloss and texture can be provided.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view of a cross section of a single fiber constituting an acetate multifilament yarn having a special cross section of the present invention.

FIG. 2 is a micrograph (magnification: 400 times) of a cross section of an acetate multifilament yarn obtained in Example 3.

FIG. 3 is a micrograph (magnification: 400 times) of a cross section of an acetate multifilament yarn obtained in Comparative Example 5.

[Explanation of symbols]

 A and C: Thick ends of the I-shaped monofilament cross section B: Central details of the I-shaped monofilament cross section

Claims (3)

[Claims] 1. A monofilament has an I-shaped cross-section, and the length ratio (L ₁ ) in the longitudinal direction and the length ratio (L) in the width direction of the cross section.
₂ ) and the number of monofilaments whose length ratio (L ₃ ) in the longitudinal direction and the length direction (L ₃ ) simultaneously satisfy the following relationship is 60 of the total number of monofilaments.
% Of cellulose acetate multifilament yarn having a special cross-section. (L ₁ ) Length of central detail (a) and total length in the longitudinal direction (b)
Ratio: b / a = 1.5 to 2.5 (L ₂ ) The ratio of the width (c) of the central detail to the width (d) of the larger one of the thick portions at both ends d / c = 1. 5 to 2.5 (L ₃ ) Ratio of width (c) of central details to total length (b) in longitudinal direction = b / c = 2.5 to 8.0 2. The special cross section according to claim 1, wherein the multifilament yarn is obtained by dry spinning a spinning dope containing 5 to 40% by weight of polyoxyalkylene glycol based on cellulose acetate flakes. Cellulose acetate multifilament yarn. 3. Cellulose acetate flakes, 5 to 40% by weight based on the cellulose acetate flakes
Special cross-section characterized by discharging a spinning dope containing polyoxyalkylene glycol of (1) and a solvent capable of dissolving the cellulose acetate flakes and polyoxyalkylene glycol from a spinneret having a rectangular spinning hole, and performing dry spinning. A method for producing a cellulose acetate multifilament yarn having: