JP2000220030A - Modified cross-section aliphatic polyester fiber and fibrous structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a modified cross-section aliphatic polyester fiber having a high gloss and high color developing properties which are not conventionally obtained, readily degradable in the natural environment and especially suitable for clothes and a fibrous structure such as a woven or a knitted fabric. SOLUTION: This modified cross-section aliphatic polyester fiber comprises an aliphatic polyester having >=130 deg.C melting point and has a value (D/d) obtained by dividing the diameter (D) of a circumscribed circle of the fiber cross section by the diameter (d) of an inscribed circle of the fiber cross section within the range of 1.1-10. Furthermore, the fibrous structure comprises the modified cross-section aliphatic polyester fiber.

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 fiber made of an aliphatic polyester. More specifically, the present invention relates to a modified cross-section aliphatic polyester fiber which is excellent in mechanical properties, gloss, and coloration properties and is particularly preferably used as a clothing fiber, and a woven or knitted fabric made of the modified cross-section aliphatic polyester fiber.

[0002]

2. Description of the Related Art Synthetic fibers made of aromatic polyesters such as polyethylene terephthalate are widely used for clothing because of their excellent mechanical properties and various fastnesses. It has long been known that synthetic fibers made of these aromatic polyesters can obtain color development similar to the luster of silk by forming a modified cross section such as a trilobal cross section. However, since the refractive index of polyethylene terephthalate was a relatively high level of about 1.6, only those having an insufficient gloss level could be obtained.

On the other hand, Japanese Patent Application Laid-Open No. 7-18903 discloses an invention in which the refractive index of a polyester polymer is lowered by copolymerization of cyclohexanedimethanol or the like to improve the color developability and gloss.
No. 6, JP-A-8-92816 and the like. In these cases, it is known that the color developability is good, but it was difficult to develop the use for clothing fibers due to the high fiber shrinkage and low strength.

Further, these aromatic polyesters containing terephthalic acid as a main carboxylic acid component have extremely high durability in a natural environment and are not easily decomposed in a natural environment. However, there is a disadvantage that it remains. At present, there is no material for clothing that is excellent in gloss, feel and color development and that is easily decomposed in a natural environment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a modified cross-sectional aliphatic material which has never been obtained before and which has high gloss, high color development, and is easily decomposed in a natural environment, and which is particularly suitable as a fiber for clothing. An object of the present invention is to provide a fibrous structure comprising a polyester fiber and an aliphatic polyester fiber having a modified cross section.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A filament (D / d) obtained by dividing the diameter (D) of the circumscribed circle of the fiber cross section by the diameter (d) of the inscribed circle of the fiber cross section in a filament made of an aliphatic polyester having a melting point of 130 ° C. or higher. ,
It can be achieved by a modified cross-section aliphatic polyester fiber characterized by being in the range of 1.1 to 10. In the modified cross-sectional aliphatic polyester fiber of the present invention, the cross-sectional form may be a three-leaf cross section. In this case, the diameter (D) of the circumscribed circle of the fiber cross section is the diameter of the inscribed circle of the fiber cross section. The value (D / d) divided by (d) is preferably 1.4 to 3.0. Also, the cross-sectional shape can be 4 to 8 leaf cross-sections. In this case, the length (h) of the perpendicular drawn from the tangent drawn to the adjacent protrusion to the lowest recess is represented by the length of the tangent (L). It is desirable that a value {(h / L) × 100} multiplied by 100 be 2 to 30. Further, from the viewpoint of high color developing property, the refractive index of the aliphatic polyester is preferably 1.50 or less, and specifically, an easily decomposable polyester containing L-lactic acid as a main component can be used. In addition, for use in clothing, the fiber must have a strength of 4 g / d or more and a boiling water shrinkage of 10%.
The following fibers are preferably used. In the case of apparel applications requiring aesthetics, a fibrous structure such as a woven or knitted fabric using at least a part of these aliphatic polyesters having a modified cross section and having a surface gloss of 90% or more is preferably used.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aliphatic polyester used in the present invention must have a melting point of 130 ° C. or higher.
When the melting point is lower than 130 ° C, the quality of the product is extremely low, such as poor stretchability due to the fusion between the single yarns and melting defects during dyeing, heat setting and friction heating. Therefore, it cannot be used for clothing.
The melting point of the aliphatic polyester used in the present invention is preferably 150 ° C. or higher, more preferably 160 ° C. or higher. Here, the melting point means a peak temperature of a melting peak obtained by DSC measurement.

Since the modified cross-section fiber of the present invention is made of an aliphatic polyester, it has a good soft feeling unlike a fiber made of an aromatic polyester. This good soft feeling is due to the fact that the Young's modulus of the fiber is clearly lower than that of the aromatic polyester fiber.

The effect of the irregular cross section is that the value (D / d) obtained by dividing the diameter (D) of the circumscribed circle of the fiber cross section by the diameter (d) of the inscribed circle of the fiber cross section is in the range of 1.1 to 10. Is preferably expressed. When the above value (D / d) is smaller than 1.1, there is almost no change from the circular cross-section fiber spun from the round hole, while when the value (D / d) is larger than 10, problems such as fibrillation occur. May occur, resulting in poor weaving. In the present invention, this value (D / d) is more preferably in the range of 1.4 to 8.0.

If the above-mentioned value (D / d) is in the range of 1.1 to 10, the cross-sectional shape of the modified cross-sectional aliphatic polyester fiber of the present invention is multi-lobular, cross-shaped, cross-shaped, W-shaped, S-shaped. , X-shape and the like. Among them, the multilobal shape is particularly preferable from the viewpoint of fibril resistance. Further, the modified cross-section aliphatic polyester fiber of the present invention may be a hollow fiber having at least one hollow portion provided inside the fiber. In this case, the inscribed circle of the fiber cross section in the present invention means an inscribed circle on the assumption that no hollow portion exists in the fiber.

When the cross section of the fiber is multi-lobed, the number of leaves is preferably 3 or 4 to 8. When the number of leaves is 9 or more, the difference from the round cross section becomes small, and the effect of the present invention is hardly obtained.

When the cross section is a three-lobe cross section, the value (D / d) obtained by dividing the diameter (D) of the circumscribed circle of the fiber cross section by the diameter (d) of the inscribed circle of the fiber cross section is 1.4. Desirably, it is 3.0. The higher this value (D / d) is, the more the fiber with good gloss can be obtained. In this case, the value (D / d) is more preferably 1.
8 to 3.0.

When the cross section is 4 to 8 leaves,
Divide the length (h) of the perpendicular from the tangent drawn on the adjacent convex part to the most concave part by the length of the tangent (L), and multiply by 100. The value {(h / L) x 100} is 2 It is preferably from 30 to 30. As this value {(h / L) × 100} is larger, fibers with better gloss can be obtained. More preferably, this value {(h / L) × 100} is 5 to 30
It is.

FIGS. 1 (a) and 1 (b) are schematic diagrams showing the cross-sectional shapes of the modified cross-linked aliphatic polyester fibers of the present invention.

The aliphatic polyester used in the present invention has a peak temperature of a melting peak obtained by DSC measurement of 130 ° C.
There is no particular limitation if above, specifically, polylactic acid, polyglycolic acid, poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxybutyrate valerate, and These blends and modified products can be used. Since these aliphatic polyesters have high biodegradability or hydrolyzability, they also have an advantage that they are easily decomposed in a natural environment.

In order to obtain a fiber having good gloss, it is necessary that the cross section of the fiber has a specific irregular cross-sectional shape as described above. In addition, the refractive index of the polymer must be 1.50 or less. Is desirable. More preferably, the refractive index is 1.45 or less.

The refractive index referred to here is measured according to JIS-K7 by an Abbe refractometer equipped with a prism, which is installed in a room capable of collecting natural light and adjusted to 23 ° C. by means of circulation of constant temperature water.
It means a value measured according to the method described in 105.

In the present invention, preferable polymers from the viewpoint of a high melting point and a low refractive index include polylactic acid which is a polyester mainly composed of L-lactic acid and polyglycolic acid which is a polyester mainly composed of glycolic acid. Can be mentioned. Main component of L-lactic acid means that 60% by weight or more of the component is composed of L-lactic acid, and a polyester containing D-lactic acid in a range not exceeding 40% by weight. Is also good.

The method for producing polylactic acid includes a two-stage lactide method in which lactide is once produced as a cyclic dimer using lactic acid as a raw material, and then a ring-opening polymerization is carried out. Is known as a one-step direct polymerization method. The polylactic acid used in the present invention may be one obtained by any production method. In the case of the polymer obtained by the lactide method, the cyclic dimer contained in the polymer evaporates during melt spinning and causes thread spots. It is desirable that the body content be 0.1 wt% or less. In addition, in the case of the direct polymerization method, since there is substantially no problem caused by the cyclic dimer, it can be said that it is more preferable from the viewpoint of spinning properties.

The higher the average molecular weight of the polylactic acid is, the more preferable it is, usually at least 50,000, preferably at least 100,000,
More preferably, it is 100,000 to 300,000. If the average molecular weight is lower than 50,000, the strength physical properties of the fiber are undesirably reduced.

Further, the polylactic acid in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other components having an ester-forming ability in addition to L-lactic acid and D-lactic acid. Other copolymerizable components include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid,
In addition to hydroxycarboxylic acids such as 6-hydroxycaproic acid, ethylene glycol, propylene glycol,
Compounds having a plurality of hydroxyl groups in a molecule such as butanediol, neopentyl glycol, polyethylene glycol, glycerin, pentaerythritol or derivatives thereof, adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2,6 -Compounds containing a plurality of carboxylic acid groups in the molecule, such as naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, and 5-tetrabutylphosphonium isophthalic acid, and derivatives thereof.

In order to reduce the melt viscosity, an aliphatic polyester polymer such as polycaprolactone, polybutylene succinate and polyethylene succinate can be used as an internal plasticizer or as an external plasticizer. Further, inorganic fine particles and organic compounds as a matting agent, a deodorant, a flame retardant, a yarn friction reducing agent, an antioxidant, a coloring pigment and the like can be added as required.

The modified cross-linked aliphatic polyester fiber of the present invention preferably has a fiber strength of 4 g / d or more and a boiling water shrinkage of 10% or less. When the strength is 4 g / d or less, it is not preferable because the thread breaks and stops during weaving, or the strength of the product is reduced due to the decrease in tear strength of the fabric or knitted fabric. The strength is more preferably at least 4.5 g / d, most preferably at least 5 g / d.

If the boiling water shrinkage of the modified cross-sectional aliphatic polyester fiber of the present invention is more than 10%, shrinkage in hot water treatment such as scouring or dyeing becomes large, and it becomes difficult to widen the fabric. Also, the texture tends to harden, which is not preferable.

The aliphatic polyester fiber having a modified cross section according to the present invention can be produced by using a known melt spinning apparatus to make the cap holes for the corresponding modified cross section. For example, when obtaining a three-leaf cross section fiber, a known T-shaped or Y
A base having a character-shaped base hole may be used. Further, in order to further increase the value (D / d) indicating the degree of irregularity, a method of reducing the die surface depth, a method of enhancing cooling, or the like can be used.

FIGS. 2 to 4 show schematic diagrams of the die holes used in the present invention. FIG. 2 is a schematic diagram showing a die hole for obtaining fibers having a three-leaf cross-sectional shape, and FIG. 3 is a schematic diagram showing a die hole for obtaining fibers having an eight-leaf cross-sectional shape. , X
It is a schematic diagram which shows the base hole for obtaining the fiber of a character-shaped cross section.

The aliphatic polyester fiber having a modified cross section according to the present invention has a high value (D / d) indicating the degree of modification of the cross section of 1.1 to 10, so that it has excellent gloss and good coloring properties. Therefore, a fibrous structure such as a fabric using the fibers exhibits high glossiness. A fibrous structure at least partially using the modified cross-sectional aliphatic polyester fiber of the present invention and having a surface gloss of not less than% is particularly suitable for use in clothing. Here, examples of the fiber structure include a string, a band, a net, and the like, in addition to a fabric such as a woven or knitted fabric or a nonwoven fabric.

[0028]

The present invention will be described in more detail with reference to the following examples. Each characteristic value in the examples was obtained by the following method.

A. Melting point Using a differential scanning calorimeter (DSC-7) manufactured by Perkin Elmer, the temperature was measured at a heating rate of 15 ° C./min, and the peak temperature of the obtained melting peak was defined as the melting point.

B. Intrinsic viscosity (η) A sample (0.100 g) was dissolved in orthochlorophenol (10 ml) and measured at 25 ° C. using an Ostwald viscometer.

C. Melt Viscosity The relationship between the shear rate at 260 ° C. and the melt viscosity was measured using a Capillograph manufactured by Toyo Seiki Co., Ltd. For measurement
Using a die with L / D = 10/1 (mm), shearing speed 1000sec ^-1
The viscosity at the time of was used as the melt viscosity of the sample.

D. Strength Orientec tensile tester (Tensilon UCT-100
), A tensile test was performed under the conditions of a sample length of 20 cm and a tensile speed of 20 cm / min, and the stress at the breaking point was taken as the fiber strength.

E. Surface glossiness A fiber serving as a sample was placed on an aluminum plate, and the 60-degree specular glossiness was measured based on JIS-Z8741 using a Japan Gloss Meter VG-107. G. FIG. Coloring property The colorability of the fabric dyed under the following conditions was visually confirmed.

Disperse dye Sumikaron Navy Blue S-2GL: 0.6% owf Tetrosin Pen: 5.0% owf Sun salt # 1200: 1.0% owf Dyeing temperature 98 ° C. × 60 minutes Bath ratio 1:50 [Example 1] 260 Melt viscosity at 1000 ° C, 1000 sec- ¹ is 12
A poly-L-lactic acid chip having a melting point of 172 ° C. and a refractive index of 1.45 (95% L-form ratio, 5% D-form ratio)
Drying was performed for 48 hours in a vacuum dryer set to ° C. The dried chips are melted at a melter temperature by a pressure melter spinning machine.
It was melted at 250 ° C and introduced into a melt pack with a spinning temperature of 260 ° C, and the Y-shaped hole shown in Fig. 2 was cut into a trilobe cross-section die (0.1 x 0.3 mm, 0.45 mm) with 36 holes. It was spun from a spinneret with holes. The base depth was 15 cm.

The spun yarn was cooled at 20 ° C. by a 30 m / min chimney wind, applied with an oil agent and converged, and then 1200 m / m
It was taken in to obtain an undrawn yarn of 225D-36f. The obtained undrawn yarn was drawn at a drawing temperature of 80 ° C, a heat setting temperature of 120 ° C and a draw ratio of 3.0 to obtain a drawn yarn of 75D-36f.

The resulting drawn yarn had a strength of 4.8 g / d and a boiling water shrinkage of 8.0%. A cross-sectional photograph of the cross section of the fiber was taken, and the value (D / d) indicating the degree of irregularity represented by circumscribed circle diameter / inscribed circle diameter was calculated to be 1.2. Using this drawn yarn as a warp and a weft, a taffeta fabric was prepared. After scouring in boiling water for 10 minutes to remove the oil agent, heat setting was performed at 120 ° C. for 2 minutes using a pin tenter. When the glossiness of the obtained woven fabric was measured, it was found to have an excellent glossiness of 92 (%). Further, the taffeta fabric had a good soft feeling.

The taffeta fabric was dyed, and the obtained dyed fabric was visually checked. As a result, it was found that a clear coloration was obtained.

Example 2 Spinning and drawing were performed in the same manner as in Example 1 except that the die surface depth was changed to 5 cm, to obtain a 75D-36f drawn yarn having a three-leaf cross section.

The strength of the obtained drawn yarn was 3.5 g / d, and the boiling water shrinkage was 7.2 (%). The value (D / d) indicating the degree of irregularity was as high as 3.0. When the surface glossiness of the obtained taffeta fabric was measured, it was a high value of 98%, and the soft feeling was good.

This taffeta fabric was dyed, and the resulting dyed fabric was visually checked. As a result, it was found that a clear color was obtained.

[Embodiment 3] 8 shown in FIG.
Except for using a leaf hole die, a drawn yarn having an eight-leaf cross section was obtained in the same manner as in Example 1.

The obtained drawn yarn had a strength of 4.3 (g / d) and a boiling water shrinkage of 6.2%. The value {(h / L) × 100} indicating the degree of irregularity was 16.2. A value indicating the degree of irregularity (D /
d) was 1.2. The surface gloss of the obtained taffeta fabric is
The value was as high as 99%, and the soft feeling was good.

The taffeta fabric was dyed, and the obtained dyed fabric was visually checked. As a result, it was found that a clear coloration was obtained. Comparative Example 1 A drawn yarn having a round cross section of 75D-36f was obtained in the same manner as in Example 1 except that a die having a 0.23D-0.30L round hole was used.

The obtained drawn yarn had a strength of 5.0 g / d and a boiling water shrinkage of 6.8%. Since the fiber is a perfect circle, the value (D / d) indicating the degree of irregularity is 1. A taffeta fabric was prepared in the same manner as in Example 1, and its surface gloss was measured.
And it was not a satisfactory level. The taffeta fabric had a good soft feel.

This taffeta fabric was dyed, and the resulting dyed fabric was visually checked. As a result, the crispness was inferior to that of Example 1.

Comparative Example 2 Polyethylene terephthalate (melting point: 260), which is an aromatic polyester, was used in place of polylactic acid.
° C, refractive index 1.56), the drying conditions were 140 ° C x 8 hours, the melter temperature was 280 ° C, the spinning temperature was 290 ° C, and the draw ratio was 4.
A three-leaf cross-sectioned drawn yarn was obtained in the same manner as in Example 1 except that the drawing temperature was changed to 90 ° C. and the heat setting temperature was changed to 130 ° C., respectively.

The strength of the obtained drawn yarn is 5.2 g / d, the boiling water shrinkage is 6.0 (%), and the value (D / d) indicating the degree of irregularity is 1.5.
However, since the refractive index was high, the surface glossiness of the taffeta fabric was as low as 75%. Moreover, the soft feeling of the taffeta fabric is insufficient, and furthermore, an alkali weight reduction treatment is required to give a sufficient soft feeling.

When this taffeta fabric was dyed and the resulting dyed fabric was visually checked, it had a dull color and was extremely poor in sharpness.

Comparative Example 3 Instead of polylactic acid, the melting point was 11
Spinning was carried out in the same manner as in Example 1, except that polybutylene succinate at 7 ° C was used, the melter temperature was 220 ° C, and the spinning temperature was 230 ° C.

The obtained drawn yarn had a strength of 2.5 g / d, a boiling water shrinkage of 82%, and a value (D / d) indicating the degree of irregularity of 1.4. The obtained drawn yarn is used as warp yarn to make a taffeta fabric,
After smelting for 10 minutes in boiling water, it shrinks violently,
The woven shape was not maintained. When this woven fabric was heat-set at 120 ° C. for 2 minutes using a pin tenter, fusion occurred and the fabric was not suitable for extremely coarse and hard clothing.

Example 4 A 75D-36 was prepared in the same manner as in Example 1 except that a spinneret having an X-shaped die hole shown in FIG. 4 was used.
Thus, a drawn yarn of f was obtained. Microscopic observation of the cross section showed that X
A fiber with a cross section of a letter is obtained, indicating the degree of irregularity (D / d)
Is 4.3, and the value {(h / L) / 100} indicating irregularity is 3
1.4.

The strength of the obtained drawn yarn was slightly lower at 3.8 g / d, and the boiling water shrinkage was 7.2%. The surface glossiness of the taffeta woven fabric made from this fiber was very good at 92%, and the soft feeling was also good.

The taffeta fabric was dyed, and the resulting dyed fabric was visually checked. As a result, it was found that a clear color was obtained.

Table 1 shows the results of Examples 1-4 and Comparative Examples 1-3.

[0055]

[Table 1]

[0056]

According to the present invention, a modified aliphatic polyester fiber having a soft feeling, high gloss and high color development, and excellent physical properties such as strength, particularly suitable for use in clothing. Is obtained. In addition, since the fiber of the present invention is made of an aliphatic polyester, it has easy decomposability in a natural environment.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating the cross-sectional shape of a modified cross-sectional aliphatic polyester fiber of the present invention. (A) 3-leaf fiber, (b) 8-leaf fiber

FIG. 2 is a schematic diagram of a die hole for obtaining a fiber having a three-leaf cross-sectional shape.

FIG. 3 is a schematic view of a die hole for obtaining a fiber having an eight-leaf cross-sectional shape.

FIG. 4 is a schematic view of a die hole for obtaining a fiber having an X-shaped cross section.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4L035 AA02 AA09 BB31 BB56 BB59 BB89 BB91 DD02 EE01 EE07 EE08 EE20 FF10 HH10 4L045 AA05 BA03 BA15 BA49 BA51 BA52 BA58 BA60 CA25 CA40 CB09 CB13 CB19 DA23 A42 A48 A42 DA48 AA50 AB07 AC07 AC08 BA01 CA00 DA01

Claims (7)

[Claims] 1. A filament made of an aliphatic polyester having a melting point of 130 ° C. or more, wherein the diameter (D) of the circumscribed circle of the fiber cross section is divided by the diameter (d) of the inscribed circle of the fiber cross section (d). D / d) is in the range of 1.1 to 10, wherein the aliphatic polyester fiber has a modified cross section. 2. The modified crosslinked aliphatic polyester fiber according to claim 1, wherein the aliphatic polyester has a refractive index of 1.50 or less. 3. The cross section is a three-lobe cross section, and the value (D / d) obtained by dividing the diameter (D) of the circumscribed circle of the fiber cross section by the diameter (d) of the inscribed circle of the fiber cross section is 1.4 to 3. 3. The modified cross-sectional aliphatic polyester fiber according to claim 1, wherein the ratio is 3.0. 4. The cross section is a 4 to 8 leaf cross section, and the length (h) of a perpendicular from the tangent line drawn to the adjacent convex portion to the lowest concave portion
Divided by the length of the tangent (L) and multiplied by 100 ｛(h / L) ×
3. The modified cross-sectional aliphatic polyester fiber according to claim 1, wherein 100 ° is 2 to 30. 5. The modified crosslinked aliphatic polyester fiber according to claim 1, wherein the aliphatic polyester is an easily degradable polyester containing L-lactic acid as a main component. 6. The modified cross-linked aliphatic polyester fiber according to claim 1, wherein the fiber has a strength of 4 g / d or more and a boiling water shrinkage of 10% or less. 7. An aliphatic polyester fiber having a modified cross-section according to any one of claims 1 to 6, wherein the aliphatic polyester fiber is at least partially used.
A fiber structure having a surface gloss of 90% or more.