JP2003055840A - Conjugated spun fiber of cellulose acetate, method for producing the same and woven or knitted fabric thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conjugated spun fiber of cellulose acetate developing fine crimp by bending different from spiral state by hot water treatment and to provide a method for producing the conjugated spun fiber and to provide a woven or knitted fabric of the conjugated spun fiber. SOLUTION: This conjugated spun fiber of cellulose acetate is obtained by joining (A) a cellulose acetate in which 74-90% of hydroxy group of cellulose is acetized to (B) a cellulose acetate in which acetized hydroxy group is larger by >=10% than that of the cellulose acetate (A) in a side-by-side type, and has an irregular cross section in fiber-axis direction and develops fine crimp different from spiral state by hot water treatment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cellulose acetate composite spun fiber capable of imparting a new texture by producing a fine crimp different from a spiral shape by hot water treatment, a method for producing the same, and a method for producing the same. Regarding woven and knitted fabrics.

[0002]

2. Description of the Related Art In recent years, in the field of textiles for clothing, various natural and
Various modifications and improvements have been made on chemical fibers. With respect to acetate fibers, the glossiness and texture have been improved by changing the fiber cross-section, surface and yarn form. In particular, in the case of acetate fibers, as a method for forming crimps, a method of continuously heating, heat setting and untwisting with a high-speed false twist spindle and a heater is predominant. However, in the method using false twist, it is difficult to form fine crimps due to the limiting factors such as fiber strength.

As a method of expressing crimps other than the false twisting method, Japanese Patent Publication No. 525/525 discloses a crimp-expressing acetate fiber which is made of spinning stock solutions having different viscosities and which is joined side by side.

[0004]

However, the crimp-expressing acetate fiber formed by the side-by-side composite spun fiber disclosed in JP-B-43-25941 has a large spiral crimp form and a fine crimp. Since it is not possible to impart shrinkage, it was not sufficient as a method for expressing a new texture.

The present invention solves the above conventional problems,
By expressing a fine crimp different from the spiral shape in the acetate fiber, it is possible to obtain a dry feeling and a swelling feeling which have not been hitherto obtained.

[0006]

The first gist of the present invention is as follows.
Cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose are acetic acid and cellulose acetate (B) in which the hydroxyl groups acetic acid are 10% or more larger than the cellulose acetate are bonded side by side, and the cross section is the fiber axis. A cellulose acetate composite-spun fiber which is a directionally irregular composite-spun fiber, in which fine crimps different from a spiral are developed by hot water treatment.

The second gist of the present invention is that cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose is acetic acid and cellulose acetate (B) in which the acetic acid hydroxyl groups are 10% or more larger than the cellulose acetate. It is a method for producing a cellulose acetate composite spun fiber, in which a spinning dope is dry-spun side by side under conditions satisfying the following formulas (1) and (2).

(1) 0.15 <Vf / Vj <0.60 (2) 1000 <Vj <1500 (wherein Vf is the take-up speed (m / min) of the composite spun yarn,
Vj is the linear velocity (m of discharge from the spinning nozzle of the composite spinning dope.
/ Min). Further, Vj is (total discharge amount of spinning dope / total hole area of spinneret). The third gist is a woven or knitted fabric containing 5% or more of the cellulose acetate composite spun fiber.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below.

The cellulose acetate composite spun fiber of the present invention comprises cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose are acetic acid, and cellulose acetate (A) in which the acetic acid hydroxyl groups are 10% or more larger than the cellulose acetate (A). It is necessary that B) is joined side by side.

The cellulose acetate composite spun fiber of the present invention comprises one component bonded side by side,
Cellulose acetate (A) extends in the fiber axis direction by hot water treatment, and the cross section of the cellulose acetate composite spun fiber is irregular in the fiber axis direction, so that the fiber axis is different from the conventional spiral shape. It is considered that minute crimps are developed by bending in the direction. In the present invention, the hot water treatment means a treatment at 80 ° C or higher.

74-90 of the hydroxyl groups of the cellulose of the present invention
Cellulose acetate (A) in which% is acetic acid exhibits elongation behavior in the fiber axis direction by hot water treatment by spinning under the condition that strain relaxation in the fiber axis direction becomes large. If the acetic acid-containing hydroxyl group is less than 74%, the dyeing fastness is deteriorated and the processing stability is deteriorated, and if it exceeds 90%, sufficient elongation cannot be obtained, and the other cellulose acetate bonded to the side-by-side (B ), The difference in elongation and contraction is insufficient, and a fine crimp different from the spiral shape cannot be obtained.

The cellulose acetate (B) may be one that is elongated or contracted by the hot water treatment, but if the acetic acid hydroxyl group is not larger than 10% as compared with the cellulose acetate (A), the cellulose acetate (B) may be expanded. The difference in elongation and contraction with (A) becomes insufficient, and a fine crimp different from the spiral shape cannot be obtained.

Further, in the present invention, it is preferable that the composite ratio of the cellulose acetate (A) is 60% or more in order to sufficiently develop the fine crimps.

Further, in the present invention, the joining form of the two types of cellulose acetate joined side by side is irregular in the fiber axis direction, and the cross section of the fiber is a random and complicated intricate uneven section. Therefore, when the hot water treatment is performed, the bending angle in the fiber axis direction and the bending direction due to the elongation and contraction of the cellulose acetate (A) and the elongation and contraction of the cellulose acetate (B) become irregular, resulting in the conventional spiral. It is considered that a fine crimp due to bending different from the crimp crimp is developed.

Next, the method for producing the cellulose acetate composite spun fiber of the present invention will be specifically described.

The composite spun fiber of the present invention comprises two kinds of cellulose acetates having different ratios of acetic acid hydroxyl groups,
Dissolve in a solvent such as methylene chloride or a mixed solvent such as methylene chloride and methanol to a concentration of 15 to 30
Each spinning dope is adjusted in the range of wt%, preferably 18 to 27 wt%. These spinning dope solutions are supplied to a nozzle pack using a known composite spinning apparatus, and both spinning dope solutions are discharged side-by-side into a high temperature atmosphere from a nozzle under the spinning conditions of the present invention.

In order to develop a fine crimp different from the spiral shape, one of the two types of cellulose acetate bonded side-by-side is elongated in the fiber axis direction by hot water treatment, and the cross section of the fiber is It must be irregular in the axial direction.

Therefore, in the present invention, it is necessary to spin the cellulose acetate (A) having an acetic acid hydroxyl group of cellulose of 74 to 90% under the condition that the strain relaxation in the fiber axis direction becomes large.

When cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose is acetic acid is spun under the condition that the strain relaxation in the fiber axis direction is large, the longitudinal direction is longer than that of ordinary fibers in the process of drying and shrinking. In the hot water treatment, the hydrophilic hydroxyl groups greatly swell in the fiber axis direction and the molecular chains extend in the longitudinal direction because the molecular chains become relaxed. It is considered that the fiber does not return to its relaxed state and shows elongation in the fiber axis direction.

When dry-spinning cellulose acetate fibers under the conventional spinning conditions, the spinning dope is discharged from the spinneret with a small hole diameter into the heated air to evaporate the solvent in the spinning dope to form yarns. At this time, the solvent in the surface layer of the fiber evaporates in an extremely short time to form a skin layer, and as the drying progresses, the solvent diffuses from the inside of the filament and as it is lost, the internal volume decreases and the internal pressure becomes negative. Although the fiber surface shrinks, the yarn remains tense in the longitudinal direction, and the shrinkage is limited to the direction perpendicular to the fiber axis. Is a very smooth fiber.

However, in the present invention, since relaxation in the fiber axis direction is a large spinning condition, surface shrinkage also occurs in the fiber axis direction, resulting in irregular and randomly complicated indentations in the fiber axis direction. It becomes a certain cross section.

In the present invention, the draft ratio Vf / Vj needs to be larger than 0.15 and smaller than 0.6 in order to increase the relaxation of strain in the fiber axis direction. Vf / Vj
When the ratio is 0.15 or less, the draft ratio is too low, and the yarn is loosened between the spinneret and the take-up roller more than the shrinkage caused by the evaporation of the solvent from the spinning stock solution discharged from the spinneret. As a result, the yarn sags, resulting in yarn breakage or fluffing.

When Vf / Vj is 0.6 or more, the draft ratio is too high, so that the strain in the fiber axis direction is not sufficiently relaxed, and the extension in the fiber axis direction by the hot water treatment becomes insufficient. The cross-sectional shape of the fiber becomes uniform in the fiber axis direction, and a fine crimp different from the spiral shape does not appear.

Further, in the present invention, the discharge linear velocity Vj is 10
It must be greater than 00 and less than 1500. When Vj is 1000 or less, stress relaxation in the fiber axis direction due to relaxation of the fiber surface layer portion after passing through the nozzle becomes insufficient with respect to shear stress which the spinning dope undergoes when passing through the fine holes of the spinning nozzle, and thus the fiber axis. The strain in the direction is not sufficiently relaxed, and the cellulose acetate (A) is insufficiently stretched in the fiber axis direction by the hot water treatment. Further, when the discharge linear velocity Vj is 1500 or more, the flow of the spun stock solution spun out becomes unstable and yarn breakage occurs.

Further, the woven or knitted fabric made of the cellulose acetate composite spun fiber of the present invention needs to have a content of the fiber of 5% or more in order to impart a crimped form and a novel texture developed by hot water treatment. is there. When it is less than 5%, the expression of a new dry feeling or swelling feeling of the woven or knitted material becomes insufficient.

Further, in the present invention, it is more preferable to arrange the cellulose acetate composite spun fiber in a woven or knitted fabric so that crimp of the fiber can be sufficiently expressed. For example, the fiber is used as a molding yarn, or the fiber is floated on the texture. Woven knitted fabrics and double-faced knitted fabrics are preferable.

[0028]

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

The characteristic values were measured according to the following methods.

(Ratio of Acetylated Hydroxyl Group) JIS L
It was measured according to the 1013A method. The proportion of acetic acid hydroxyl groups in each component was determined by using fibers obtained by spinning single component fibers under the same conditions.

(Crimping developability) A sock knitted fabric was prepared, and 120
After treating with hot water at ℃ for 30 minutes, the texture was evaluated. The excellent texture due to the appearance of fine crimps due to bending was evaluated as ◯, the slightly excellent texture was evaluated as Δ, and the poor texture was evaluated as ×.

(Evaluation of texture) Cryptogenic cellulose acetate composite spun fiber and false twisted yarn of 33 dtex / 24 f polyethylene terephthalate fiber were 1400 T /
After twisting with M, a tubular knitted fabric was prepared and dyed at 120 ° C. to evaluate the texture. Compared to the one using a single component having no crimp-developing property and not having the crimp-expressing property, the one having excellent bulkiness and bulging feeling was marked with ◯, the one having a slightly excellent feeling was marked with Δ, and the one having the same level as the conventional one was marked with x.

(Dyeing fastness to washing) The obtained yarn was knitted into a cylinder knit, and the knitted fabric was scoured at 95 ° C for 30 minutes by a conventional method, and then disperse dye (Teratop manufactured by Kyowa Sangyo Co., Ltd.). Blue), concentration 3% (based on fiber weight), bath ratio 1:
High-pressure dyeing is carried out at 130 ° C. for 30 minutes in 20 dyeing baths. The obtained tubular knit is washed under the conditions of JIS L-0844 Washing Test No. A-1. The obtained tubular knitting is visually evaluated, and no change is indicated by ◯, slight fading is indicated by Δ, and fading is indicated by x.

(Ratio of Acetylated Hydroxyl Group) JIS L
It was measured according to the 1013A method. The proportion of acetic acid hydroxyl groups of each component was determined by using fibers obtained by treating the single component fibers under the same conditions.

(Examples 1 to 6, Comparative Examples 1 to 6) Cellulose acetate shown in Table 1 was added to 91% by weight of methylene chloride /
The solution was dissolved in a mixed solvent of 9% by weight of methanol to prepare a spinning dope. Using these spinning dope, by the dry spinning method,
Under the conditions shown in Table 1, side-by-side type cellulose acetate composite spun fibers were obtained. Table 1 shows the evaluation results of the obtained composite spun fiber.

In Comparative Example 1, since Vj is 1000 or less, the elongation of the cellulose acetate (A) in the fiber axis direction due to the hot water treatment is insufficient, so that minute crimps due to bending do not appear and the bulkiness is high. Feeling and swelling were not obtained.

In Comparative Example 2, since Vj was 1500 or more, the flow of the spun spinning solution became unstable and yarn breakage occurred.

In Comparative Example 3, 74% of the hydroxyl groups of cellulose were used.
Since the cellulose acetate (A) whose acetic acid is less than 100% is used, the dyeing fastness is deteriorated.

In Comparative Example 4, 90% of the hydroxyl groups of cellulose were used.
% Or more of acetic acid-containing cellulose acetate (A) is used, extension with cellulose acetate (B),
The difference in shrinkage was insufficient, fine crimps due to bending different from spiral were not obtained, and neither bulkiness nor bulge was obtained.

In Comparative Example 5, since the cellulose acetate (B) has 10% or more larger acetic acid hydroxyl groups than the cellulose acetate (A), the difference in elongation and shrinkage with the cellulose acetate (A) becomes insufficient. However, a fine crimp different from the spiral was not obtained, and neither bulkiness nor bulging was obtained.

In Comparative Example 6, since Vf / Vj is high and Vj is low, the spinning is carried out under the usual acetate spinning conditions.
Fine crimps due to bending could not be obtained, and neither bulkiness nor bulging was obtained.

[0042]

[Table 1]

[0043]

EFFECTS OF THE INVENTION The cellulose acetate composite spun fiber according to the present invention develops a fine crimp due to bending different from a spiral shape by the hot water treatment, and can improve texture such as bulkiness and swelling. Since it has a unique and complicated ruggedness that is completely different from the surface morphology of the fibers, it gives a dry feeling and a swelling feeling that are unprecedented for acetate.

Continued front page    (72) Inventor Akihiro Miyao             Mitsubishi Rayon, 3 Kaigan Dori, Toyama City, Toyama Prefecture             Toyama Office Co., Ltd. F-term (reference) 4L041 AA03 BA02 BA05 BA09 BB08                       BD12 CA57 DD14 EE10                 4L048 AA13 AA30 AA55 CA00 CA13

Claims (4)

[Claims] 1. A cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose are acetic acid and a cellulose acetate (B) in which the hydroxyl groups acetic acid of which are 10% or more larger than the cellulose acetate are bonded side by side. A cellulose acetate composite spun fiber, which is a composite spun fiber having a cross section irregular in the axial direction of the fiber and in which fine crimps different from a spiral shape are developed by hot water treatment. 2. The cellulose acetate composite spun fiber according to claim 1, wherein the composite ratio of cellulose acetate (A) is 60% or more. 3. A spinning stock solution of cellulose acetate (A) in which 74 to 90% of the hydroxyl groups of cellulose are acetic acid and cellulose acetate (B) in which the hydroxyl groups acetic acid of which are greater than 10% are larger than the following formula. (1)
~ A method for producing a cellulose acetate composite spun fiber, which is dry-spun side by side under the condition of (2). (1) 0.15 <Vf / Vj <0.60 (2) 1000 <Vj <1500 (In the formula, Vf is the take-up speed (m / min) of the composite spun yarn,
Vj is the linear velocity (m of discharge from the spinning nozzle of the composite spinning dope.
/ Min). Further, Vj is (total discharge amount of spinning dope / total hole area of spinneret). ) 4. A woven or knitted fabric containing 5% or more of the cellulose acetate composite spun fiber according to claim 1 or 2.