JPH07216651A - Acetate fiber and its production - Google Patents

Abstract

PURPOSE:To obtain an acetate fiber having softness and considerable bulky feeling. CONSTITUTION:This acetate fiber has a side-by-side conjugate structure consisting of a cellulose or a cellulose acetate having an acetylation degree of <48.8% and a cellulose triacetate having an acetylation degree of 56.2-62.5%. The areal ratio of the constituent component on the cross-section varies in the direction of the fiber axis and the fiber has a bulkiness of >=2.0cm<3>/g. It can be produced by the alkali treatment of a precursor fiber having a side-by- side conjugate structure consisting of a cellulose diacetate having an acetylation degree of <56.2% and a cellulose triacetate having an acetylation degree of >=56.2% and having an areal ratio of the constituent component on the cross-section varying in the direction of fiber axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acetate fiber having a soft feeling and a large swelling feeling.

[0002]

BACKGROUND OF THE INVENTION Acetate fibers are widely used as a material for clothing because of their characteristics such as high gloss, dry feel, deep color tone, and excellent affinity with other fibers. It lacks the bulge. For this reason, proposals have been made to improve the texture in the spinning process or post-processing, such as composite spinning using two types of spinning dope, modified cross-section based on changes in nozzle hole shape, or chemical processing in post-processing. There is a proposal to add bulkiness by physical treatment, etc., but in both cases, there is no swelling feeling even if there is a swelling feeling, or there is no swelling feeling even if there is a soft feeling It has not yet been possible to obtain an acetate fiber having a feeling at the same time.

[0003]

The present invention has been accomplished based on the combination of composite spinning and chemical post-processing, and it is an object of the present invention to provide an acetate fiber having both a soft feeling and a large swelling feeling. .

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a side-by-side composite structure of cellulose or cellulose acetate having an acetylation degree of less than 48.8% and cellulose triacetate having an acetylation degree of 56.2 to 62.5%. None, an acetate fiber characterized in that the area ratio of the constituents in the fiber cross section varies along the fiber axis direction, and has a bulkiness of 2.0 cm ³ / g or more, and further, a fiber of the acetate fiber The area ratio of the cellulose triacetate component in the cross section is ± 10 along the fiber axis direction with respect to the average value of the area ratio of the cellulose triacetate component in the entire fiber.
% Acetate fiber having a fluctuation range of 5% or more, and cellulose diacetate having an acetylation degree of less than 56.2% and an acetylation degree of 5
A precursor fiber having a side-by-side composite structure with 6.2% or more of cellulose triacetate and having an area ratio of constituent components in the fiber cross section varying along the fiber axis direction is treated with an alkali. It is in the method of manufacturing fibers.

The acetate fiber of the present invention has a side-by-side composite structure of two kinds of constituents, one constituent being cellulose or cellulose acetate having an acetylation degree of less than 48.8%, and the other constituent. The constituent component is cellulose triacetate having an acetylation degree of 56.2 to 62.5%.

Further, in the acetate fiber of the present invention, the area ratio of the constituent components in the fiber cross section varies along the fiber axis direction. If the cellulose triacetate component is used as a reference, the acetate fiber of the constituent component in the fiber cross section is The ratio occupied by the cellulose triacetate component, that is, the area ratio of the cellulose triacetate component has a fluctuation range of ± 10% or more along the fiber axis direction with respect to the average value of the area ratio of the cellulose triacetate component in the entire fiber. There is.

Further, the acetate fiber of the present invention has a bulk height of 2.0 cm ³ / g or more as measured by the measuring method in the examples described below, and the high bulkiness varies in area ratio. In addition to the soft feeling provided by the constituents of, it brings a large swelling feeling.

Cellulose, which is one of the components constituting the acetate fiber of the present invention, or cellulose acetate having a degree of acetylation of less than 48.8%, has a degree of acetylation of 48.8% to 5 described below.
Cellulose diacetate of less than 6.2% is modified by alkali treatment, and cellulose having an acetylation degree of 0% to a low acetylation degree of less than 48.8% depending on the degree of saponification in the alkali treatment. It can be any ingredient up to acetate.

The other component, acetylation degree 56.
2% or more of cellulose triacetate has an acetylation degree of 5
6.2 to 62.5% of cellulose triacetate is unaffected or slightly affected by the alkali treatment selectively targeting cellulose diacetate.

The acetate fiber of the present invention has a side-by-side composite structure of cellulose diacetate having an acetylation degree of less than 56.2% and cellulose triacetate having an acetylation degree of not less than 56.2% as follows: It can be obtained by producing a precursor fiber in which the area ratio of the constituent components in the fiber cross section varies along the fiber axis direction, and subjecting this precursor fiber to an alkali treatment.

Cellulose diacetate having an acetylation degree of less than 56.2% and an acetylation degree of 56.2% or more, preferably 62.
Cellulose triacetate of 5% or less is dissolved in a single solvent such as methylene chloride or a mixed solvent such as methylene chloride and methanol to prepare spinning stock solutions in which the concentration of each solution is adjusted to an appropriate range. Then, using two kinds of spinning dope, each is supplied to a nozzle pack, the spinning dope speed and the spinning dope temperature at the confluence of the two spinning dopes are set to appropriate ranges, and the constituent components are attached side by side. The precursor fiber is obtained by dry-spinning which is discharged from a combined composite spinning nozzle into a high temperature atmosphere and the solvent is volatilized.

The set composite ratio (weight ratio) of the cellulose diacetate component and the cellulose triacetate component constituting the precursor fiber is not particularly limited and may be determined according to the purpose, but a preferable composite ratio is cellulose. Diacetate component / Cellulose triacetate component = 20
/ 80 to 80/20.

In the production of the precursor fiber, the area ratio of the cellulose triacetate component in the fiber cross section of the acetate fiber of the present invention is ± 10% along the fiber axis direction with respect to the average value of the area ratio of the cellulose triacetate component in the whole fiber. In order to have the above fluctuation range, the area ratio of the constituent components in the fiber cross section of the precursor fiber varies along the fiber axis direction, and more specifically, the area ratio of the cellulose triacetate component in the fiber cross section is also the entire fiber. 10% or more, preferably ± 10% or more along the fiber axis direction with respect to the average value of the area ratio of the cellulose triacetate component in
It is necessary to form a fluctuation range of 20% or more.

In order to form such a fluctuation range, when two kinds of spinning dope are joined together during the production of the precursor fiber, (1) the spinning dope flow rate at the joining portion is 0.05 cc / mm ² · m.
In the case of in or more and 0.10 cc / mm ² · min or less, the spinning dope concentration is increased to more than 20% by weight, and the spinning dope temperature is set to less than 60 ° C. (2) The spinning dope flow rate at the joining portion is If it exceeds 0.10 cc / mm ² · min and 0.25 cc / mm ² · min or less, the spinning dope concentration is 21% by weight or less and the spinning dope temperature is less than 60 ° C, or the spinning dope concentration is 21% by weight. %, And the spinning dope temperature is less than 70 ° C., or (3) the spinning dope flow rate at the junction is 0.25 cc / m 2.
Increase to exceed m ² · min.

The concentration of the spinning dope can be changed by adjusting the concentration at the time of preparing the spinning dope or by adding the solvent used at the time of preparing the spinning dope before supplying to the nozzle pack. Two
The spinning dope flow rate at the merging portion of the seed spinning dope can be adjusted by controlling the supply amount of the spinning dope to the nozzle pack or changing the piping area of the joining portion. The spinning dope temperature can be adjusted by a method of passing the spinning dope through a heat exchanger or the like immediately before supplying it to the nozzle pack, or heating the nozzle pack.

Next, the precursor fiber is treated with an alkali to obtain the acetate fiber of the present invention. The alkali treatment is carried out by immersing the precursor fiber in an aqueous solution of an alkali compound such as sodium hydroxide or calcium carbonate. Done by. The alkali compound, the alkali concentration, the temperature, and the time are appropriately determined according to the intended product, but the preferable alkali treatment conditions are, in the case of using sodium hydroxide, a concentration of sodium hydroxide of less than 5% by weight, 30 ° C or more and 100 ° C or more. The processing temperature is as follows and the processing time is not more than 15 minutes.

By such alkali treatment, the cellulose diacetate component of the precursor fiber is selectively saponified and a high shrinkage occurs, and the area ratio of the cellulose triacetate component in the fiber cross section of the precursor fiber fluctuates along the fiber axis direction. Therefore, the obtained fiber exhibits a large and random crimp in the entire fiber due to the uneven distribution of the high shrinkage portion in the axial direction of the fiber, and exhibits a bulk height of 2.0 cm ³ / g or more. A large swelling feeling is exhibited in combination with the expression of softness due to the treatment.

In the alkali treatment of the precursor fiber, the composite ratio of the precursor fiber affects the appearance of crimps, and as the ratio of the cellulose diacetate component increases, the swelling feeling increases but the soft feeling decreases, and the cellulose triacetate decreases. As the ratio of the components increases, the softness increases, but the bulge tends to decrease. Further, this tendency is magnified as the fluctuation range of the area ratio of the cellulose triacetate component in the fiber cross section along the fiber axis direction increases.

[0019]

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

The conditions in the measuring methods of the bulky height showing the bulging feeling and the texture showing the soft feeling in Examples and Comparative Examples are shown below. Bulkiness: A sample fiber is wound under a tension of 0.1 g / d on a groove portion of a roll having a groove portion having a width of 6 mm and a depth of 33.5 mm, and the weight W of the sample wound on the groove portion and the groove portion of the sample are The volume V occupied is measured, and the bulk altitude D (cm ³ / g) is calculated by the formula D = V
Calculated from / W. Feeling: Softness was judged by a sensory test, and was marked with ◎, ○, △, × in order from the most favorable one.

(Example 1) Cellulose triacetate (TA) having an average acetylation degree of 61.6% and an average acetylation degree of 55.2%
Cellulose diacetate of was dissolved in a mixed solvent of methylene chloride / methanol (= 91/9) to prepare a cellulose triacetate spinning stock solution and a cellulose diacetate spinning stock solution having a stock solution concentration of 22% by weight. Using these spinning stock solutions, the spinning stock solution flow velocity at the confluence of these two spinning stock solutions was 0.30 cc / mm ² · min, the spinning stock solution temperature was 80 ° C., and the cellulose diacetate component / cellulose triacetate component was prepared by the dry spinning method. = 50/50 composite ratio (weight ratio), composite spinning was performed, and 75 denier, 2
A 0 filament precursor fiber was obtained.

Next, the precursor fiber was immersed in an alkaline aqueous solution under the following conditions. Alkaline aqueous solution 1% by weight aqueous solution of sodium hydroxide Temperature 60 ° C Time 10 minutes Bath ratio 1: 100 The obtained acetate fiber was a side-by-side composite of cellulose with an acetylation degree of 0% and cellulose triacetate with an acetylation degree of 61.6%. It has a structure, and Table 1 shows the physical properties, bulkiness, and texture of the fiber.

Example 2 Using the same cellulose triacetate spinning dope and cellulose diacetate spinning dope as used in Example 1, the spinning dope flow rate at the confluence of the two spinning dope solutions was 0.30 cc / mm ² · min, The spinning solution temperature was set to 80 ° C., and the composite spinning was carried out by a dry spinning method at a composite ratio of cellulose diacetate component / cellulose triacetate component = 35/65 to obtain a precursor fiber of 75 denier and 20 filaments. Next, this precursor fiber was alkali-treated under the same conditions as in Example 1. The obtained acetate fiber had a side-by-side composite structure of cellulose and cellulose triacetate having an acetylation degree of 61.6%, and Table 1 shows the physical properties, bulkiness and texture of the fiber.

Example 3 Using the same cellulose triacetate spinning dope and cellulose diacetate spinning dope as used in Example 1, the spinning dope flow rate at the confluence of the two spinning dope solutions was 0.30 cc / mm ² · min, The spinning stock solution temperature was set to 80 ° C., and the composite spinning was performed by a dry spinning method at a composite ratio of cellulose diacetate component / cellulose triacetate component = 65/35 to obtain a precursor fiber of 75 denier and 20 filaments. Next, this precursor fiber was alkali-treated under the same conditions as in Example 1. The obtained acetate fiber had a side-by-side composite structure of cellulose and cellulose triacetate having an acetylation degree of 61.6%, and Table 1 shows the physical properties, bulkiness and texture of the fiber.

Comparative Example 1 Using the same cellulose diacetate spinning dope and cellulose triacetate spinning dope as used in Example 1, the spinning dope flow rate at the confluence of the two spinning dope solutions was 0.08 cc / mm ² · min, The spinning stock solution temperature was set to 80 ° C., and the composite spinning was performed by a dry spinning method at a composite ratio of cellulose diacetate component / cellulose triacetate component = 50/50 to obtain a precursor fiber of 75 denier and 20 filaments. Next, this precursor fiber was alkali-treated under the same conditions as in Example 1. The obtained acetate fiber had a side-by-side composite structure of cellulose and cellulose triacetate having an acetylation degree of 61.6%, and Table 1 shows the physical properties, bulkiness and texture of the fiber.

Comparative Example 2 According to a conventional method for producing cellulose triacetate fiber, cellulose triacetate having an average degree of acetylation of 61.6% was dissolved in a mixed solvent of methylene chloride / methanol (= 91/9) to give a stock solution concentration of 2
A 1.95 wt% stock solution of cellulose triacetate spinning was prepared. Using this spinning dope, dry spinning produces 75
A denier, 20 filament cellulose triacetate fiber was obtained. Table 1 shows the physical properties, bulkiness, and texture of the obtained fibers.

[0027]

[Table 1]

The acetate fiber of the present invention of Example 1 was slightly lower in strength and elongation than the conventional acetate fiber, but had no problem in practical use. Further, the acetate fiber of the present invention has a fluctuation range of ± 20% or more in the fiber axis direction with respect to the average value of the area ratio of cellulose triacetate in the fiber cross section of the whole fiber, and within the fiber of Comparative Example 1, Compared with the acetate composite fiber having no change in the area ratio of the constituent components of Example 1 and the conventional cellulose triacetate fiber of Comparative Example 2, a large swelling feeling is exhibited due to its extremely high bulk height, and its texture is also very good. It was a feeling. Examples 2-3
The acetate fiber of the present invention in which the composite ratio of (1) was changed also had very good bulging feeling and soft feeling as in Example 1.

[0029]

The acetate fiber of the present invention has a soft texture and a large swelling feeling, which is completely different from the dry and silky texture of the conventional acetate fiber. Therefore, the acetate fiber of the present invention is capable of expressing a texture and volume feeling which are completely different from those of the conventional acetate fiber, and expands the application as the acetate fiber, and its value is extremely large.

Claims (3)

[Claims] 1. A side-by-side composite structure of cellulose or cellulose acetate having an acetylation degree of less than 48.8% and cellulose triacetate having an acetylation degree of 56.2 to 62.5%, and having an area ratio of constituent components in a fiber cross section. Varies along the fiber axis direction and has a bulk height of 2.0 cm ³ / g or more. 2. The area ratio of the cellulose triacetate component in the fiber cross section has a fluctuation range of ± 10% or more along the fiber axis direction with respect to the average value of the area ratio of the cellulose triacetate component in the entire fiber. The acetate fiber according to claim 1, which is characterized in that. 3. A side-by-side composite structure of cellulose diacetate having an acetylation degree of less than 56.2% and cellulose triacetate having an acetylation degree of 56.2% or more, wherein the area ratio of the constituent components in the fiber cross section is the fiber axis. The method for producing an acetate fiber according to claim 1, wherein the precursor fiber varying along the direction is treated with an alkali.