JPH10130957A - Polymer blend fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber, having excellent mechanical strength possessed by a polyester fiber and excellent touch feeling, dyeability and hygroscopicity possessed by a cellulose ether fiber at a low cost. SOLUTION: This polymer blend fiber comprises 5-60wt.% cellulose ester containing a plasticizer for the cellulose ester in an amount of 15-35% based on the cellulose ester and 95-40wt.% polyester as components. The phase separation of the polyester in the form of the sea and the cellulose ester in the form of islands is caused in an optional cross section at right angles from the fiber axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polymer blend fiber comprising a polyester and a cellulose ester containing a plasticizer. Specifically, a polymer with a polyester component that is phase-separated in a sea-like form to form a continuous matrix, and a cellulose ester component that is an island-shaped dispersed phase oriented in the fiber axis direction, and that has excellent moisture absorption performance. Related to blended fibers.

[0002]

2. Description of the Related Art Synthetic fibers obtained by melt spinning are:
It is in an industrially superior position, and in particular, polyester fibers mainly composed of polyethylene terephthalate and polybutylene terephthalate have become mainstream. Polyester fiber has excellent mechanical strength and is manufactured by the melt spinning method.
Various fiber yarns can be formed, and by utilizing their characteristics, they are used not only for clothing but also for various applications ranging from fibers for industrial materials.

[0003] On the other hand, cellulose acetate is not only excellent in color developability, but also has moderate moisture absorption, heat retention, and elasticity, making use of its dry texture and comfortable feeling when worn.
It is used for various clothing applications, but has the disadvantage that it is inferior to synthetic fibers in terms of mechanical properties and the like.

[0004] Cellulose acetate is industrially formed into fiber yarns by a dry spinning method. In the dry spinning method, since a large amount of solvent is used for spinning, a large amount of energy is required for spinning and solvent recovery, and generally, the productivity is low and the production cost is relatively high. On the other hand, the melt spinning method has advantages in that energy cost is low, productivity is high, and various kinds of fibers can be spun.
However, despite these advantages, the reason why the melt spinning method was difficult to apply to cellulose acetate is that
This is because when cellulose acetate is heated to around its melting point, thermal decomposition occurs.

[0005] Among the industrial products, cellulose derivatives having high thermoplasticity include cellulose diacetate, ethylcellulose, nitrocellulose and the like. Therefore, it is necessary to incorporate a large amount of a plasticizer for melt spinning. For example, as an attempt to melt-spun cellulose acetate containing a large amount of a plasticizer to obtain a single fiber of cellulose acetate, JP-B-53-11564, JP-B-61-60165, and JP-B-3-62447. Japanese Patent Publication No. 7-78288, etc., after melt spinning a hollow fiber of cellulose acetate containing a large amount of plasticizer, extract the plasticizer by solution treatment or the like, and hollow fiber for ultrafiltration or hemodialysis etc. Proposals have been made to produce membranes.

There have been many attempts to develop a fiber having the properties of semi-synthetic fibers such as cellulose acetate and the properties of synthetic fibers prepared by melt spinning such as polyester. It has been done. For example, a proposal has been made to obtain a core-sheath composite fiber of a cellulose derivative and a polyester by a composite spinning method for the purpose of imparting hygroscopicity to the fiber. JP 52
JP-A-85518 proposes that a fiber-forming polyester is used as a core component and a cellulose ester containing 50% by weight or less of a water-soluble polymer is used as a sheath component to perform composite spinning to obtain a core-sheath composite fiber. Kaihei 4-300
Japanese Patent Publication No. 324 proposes a core-in-sheath type composite fiber having a plasticizer-containing cellulose acetate as a core component and polyester as a sheath component.

On the other hand, blending polymers have been used as a means of modifying various synthetic fibers to improve texture, dyeability, and impart various functions. There is a method in which a polymer blend fiber is obtained by melt spinning using a raw material with a normal spinning machine for spinning a single fiber. This method is a composite spinning method that requires at least two types of melt extruders and polymer lines in one spinning facility, or a mixed spinning method that requires at least two types of melt supply devices and two polymer lines in one spinning facility. Unlike the method, two or more kinds of pre-blended polymers are used as raw materials and melt-spun by a normal single-fiber spinning equipment, which has one melt extruder and one polymer line.
This is a technique for obtaining polymer blend fibers.

However, when a fiber is produced by blending a semi-synthetic polymer such as cellulose acetate and a thermoplastic polymer such as polyester, the basic differences between the two fiber production processes as described above and Due to the difference in thermophysical properties between the two polymers, it was very difficult to blend the two in the fiber production stage and melt-spun into a fiber by a single spinning machine. Therefore, in practice, polyester fibers produced by the melt spinning method and cellulose acetate fibers produced by the dry spinning method are almost always mixed and used in the post-processing step.

[0009]

SUMMARY OF THE INVENTION As described above, a plasticizer-rich cellulose derivative is solely formed on a hollow fiber membrane or the like.
Alternatively, proposals have been made regarding a core-sheath composite fiber of a plasticizer-containing cellulose derivative and polyester using a composite spinning method, but in the conventional method, the excellent mechanical strength of the polyester fiber and the cellulose ester fiber have There is no fiber which has both excellent feeling and moisture absorption performance and which can be obtained at a relatively low cost. Therefore, the present invention is a fiber that can be used in various fields including clothing applications, is low-cost, and has excellent mechanical strength of polyester fiber and excellent feeling and functionality of cellulose ester fiber. It is an object of the present invention to provide a polymer blend fiber having a novel texture, excellent dyeability, and moisture absorption performance.

[0010]

The gist of the present invention is to provide a plasticizer for a cellulose ester with respect to a cellulose ester.
A fiber comprising 5 to 60% by weight of a cellulose ester containing 15 to 35% and 95 to 40% by weight of a polyester, wherein the polyester is sea-like and the cellulose ester is an island in any cross section perpendicular to the fiber axis. It is a polymer blend fiber characterized by being phase-separated in a shape.

In the present invention, the cellulose ester is preferably a cellulose diacetate having an acetylation degree of 48.8% to 56.2%, and the plasticizer content of the cellulose ester relative to the cellulose ester is 21 to 35.
%. Further, the melting point of the polyester used in the present invention is preferably 240 ° C. or less. Among the thus obtained polymer blend fibers, fibers having excellent mechanical properties satisfying the following formula (1) are preferable.

DS × √DE ≧ 10 (1) where DS indicates fiber strength and DE indicates elongation at break.

Further, the moisture absorption at 20 ° C. and a relative humidity of 65% is 0.5% or more, and at 30 ° C. and a relative humidity of 9%.
It is preferable that the polymer blend fiber has a moisture absorption of 1.0% or more at 0% and has excellent moisture absorption performance.

FIG. 1 shows an electron micrograph of a cross section in the direction perpendicular to the fiber axis of the present invention. FIG. 1 is a scanning electron micrograph (× 1,100) obtained by etching a cross section of a fiber composed of 30% by weight of a plasticizer-containing cellulose acetate component and 70% by weight of a polyester component in a direction perpendicular to a fiber axis with acetone. The polyester component is a sea-like continuous phase,
The cellulose acetate component has an island shape oriented in the fiber axis direction.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of the cellulose ester used in the present invention include cellulose (mono) acetate,
Cellulose diacetate, cellulose triacetate,
Examples include cellulose acetate butyrate, benzylcellulose, or a mixture thereof. Among them, cellulose (mono) acetate, cellulose diacetate and cellulose triacetate are exemplified. Among them, cellulose diacetate having an acetylation degree of 45 to 59.5% is preferred from the viewpoint of thermoplasticity and melt fluidity.

The plasticizer used is not particularly restricted but includes, for example, diethyl phthalate, triacetin, 1, 3
A well-known plasticizer generally used for cellulose acetate such as a polyol ester compound such as butylene glycol diacetate may be used, but diethyl phthalate is preferably used.

The polyester used in the present invention preferably has a melting point of 240 ° C. or less. Typical examples of such a polyester include polybutylene terephthalate, polypropylene terephthalate, or polyethylene terephthalate with isophthalic acid or adipine. Examples thereof include copolymerized polyesters having a melting point of 240 ° C. or lower, which are obtained by copolymerizing dicarboxylic acids such as acid and sebacic acid, and long-chain alkylene glycol. In the present polyester polymer, known antioxidants, anti-coloring agents, lubricants,
An additive such as a flame retardant may be included.

The polymer blend fiber of the present invention has a sufficient mechanical strength because the polyester component forms a continuous phase in a sea-like manner in an arbitrary cross section perpendicular to the fiber axis. It is possible to fiberize by a manufacturing process for use.

Assuming that the tensile strength of the polymer blend fiber of the present invention is DS and the breaking elongation is DE, in order to achieve practical mechanical properties and mechanical strength, the fiber properties satisfy the following formula (1). Is preferred.

DS × √DE ≧ 10 (1)

Further, the polymer blend fiber of the present invention comprises:
In any cross section perpendicular to the fiber axis, the cellulose ester component is phase-separated in the form of islands highly oriented in the fiber axis direction, and the unique texture of the cellulose ester fiber corresponds to the blend ratio of the cellulose ester polymer. Is expressed.

In the polymer blend fiber of the present invention,
As shown in FIG. 1, in order to make the polyester component a continuous phase as a sea component and the cellulose ester component as a highly oriented island component, 5 to 60% by weight of a plasticizer-containing cellulose ester component in a polymer blend fiber is used. The component must be 95 to 40% by weight, and in particular, the plasticizer-containing cellulose ester component is preferably 10 to 50% by weight, and the polyester component is preferably 90 to 50% by weight. Ingredient 1
5 to 40% by weight, 85 to 60% by weight of polyester component
It is preferable from the viewpoint of expressing both characteristics.

When the content of the plasticizer-containing cellulose ester component is less than 5% by weight or the content of the polyester component exceeds 95% by weight, the resulting polyester blend fiber has insufficient feeling of cellulose ester. If the polyester component is less than 40% by weight or the plasticizer-containing cellulose ester component exceeds 60% by weight, the polyester component does not become a sea component and the fiber strength becomes insufficient.

The polymer blend fiber of the present invention can be produced by any known melt spinning equipment.
For example, as a polyester, a polybutylene terephthalate chip having a melting point of 240 ° C. or less is used, and a weight ratio of polybutylene terephthalate / cellulose diacetate is obtained by using a dried cellulose diacetate chip containing a plasticizer and having an acetylation degree of about 55%. From the extruder hopper.
The mixture is melt-extruded by a single-screw extruder having a temperature gradient from 40 ° C to 280 ° C, and the mixed melt stream is melt-spun at a spinning temperature of 255 to 285 ° C through a spinneret having a circular spinning hole. After the discharged yarn is cooled and solidified by cooling air, an oil agent is applied and wound up to obtain an undrawn yarn. Further, the obtained undrawn yarn was passed through a hot roller at 60 to 90 ° C., and the maximum drawn breaking ratio of the undrawn yarn was 7%.
The drawn yarn can be obtained by drawing at about 0%, and by drawing while contacting a hot plate at 130 to 150 ° C.

[0025]

EXAMPLES The present invention will be described more specifically with reference to the following examples. In addition, each characteristic value in an Example is measured or evaluated by the following method.

(Intrinsic Viscosity) The intrinsic viscosity was measured at 25 ° C. using an Ubbelohde viscometer after dissolving the sample in a phenol / tetrachloroethane (50/50) mixed solvent.

(Shrinkage ratio of boiling water) This is a value calculated by measuring the length of the yarn before and after immersion in boiling water for 30 minutes under a load of 1/30 (g / d).

(Hand) The obtained fiber was knitted and evaluated organoleptically as follows. A: Hand feeling very close to cellulose acetate fiber. ：: A feeling similar to cellulose acetate fiber is exhibited. Δ: Usually a feeling close to that of polyester fiber, but slightly showing a feeling like acetate fiber. ×: The feeling is almost the same as that of a normal polyester fiber.

(Hygroscopic performance) After knitting the obtained fiber,
The knitted fabric was dried under vacuum at 65 ° C. for 24 hours, and the dry weight of the knitted fabric was measured. Then, the knitted fabric is subjected to 20 ° C. and a relative humidity of 6
Each was allowed to stand for 24 hours in an atmosphere adjusted to 5%, 30 ° C. and 90% relative humidity. The moisture absorption of the fiber was determined by subtracting the dry weight from the weight of the knitted fabric after standing for 24 hours in the moisture-absorbed state.

Example 1 A dried polybutylene terephthalate chip having an intrinsic viscosity of 1.09 (hereinafter referred to as PB)
(Abbreviated as T) (Toughpet manufactured by Mitsubishi Rayon Co., Ltd.)
And a dried cellulose diacetate chip having a plasticizer content of about 23% and a degree of acetylation of about 55% (Acet 35, VP-6001, manufactured by Daicel Craft Co., Ltd .; hereinafter abbreviated as DAC), and the weight of PBT and DAC The mixture was blended to have a ratio of 80:20, supplied from an extruder hopper, and melt-extruded by a single-screw extruder having a temperature gradient from 245 ° C to 271 ° C. The mixed melt stream was passed through a spinneret having 24 circular spinning holes having a hole diameter of 0.16 mm and a spinning temperature of 26.
It was melt spun at 8 ° C. After the discharged yarn was solidified by cooling with cooling air, an oil agent was applied and wound at a speed of 600 m / min. This melt spinning was successfully performed without yarn breakage. Next, the obtained undrawn yarn was passed through a hot roller at 80 ° C., and the maximum drawn breaking ratio (6.43) of the undrawn yarn was obtained.
) And stretched by contacting with a hot plate at 145 ° C., and wound at a speed of 400 m / min to obtain a drawn yarn of 40 denier / 24 filaments. Table 1 shows the evaluation results of the fiber properties.

Example 2 The melt spinning temperature was set at 265 ° C., and the discharge amount of the mixed polymer from the spinneret was increased to 75 ° C.
The procedure was performed in the same manner as in Example 1 except that the denier / 24 filament drawn yarn was increased so as to obtain a drawn yarn. The maximum draw ratio of the undrawn yarn of this example was 5.55 times, and the same drawing heat treatment as in Example 1 was performed to obtain a drawn yarn. Table 1 shows the evaluation results of the fiber properties.

(Example 3, Comparative Examples 1 to 3) The polymer blend composition and the spinning conditions were changed as shown in Table 1, respectively. In addition, Comparative Examples 2 and 3 were manufactured only by the melt spinning step without going through the drawing and twisting step. Table 1 shows the evaluation results of the fiber properties.

[0033]

[Table 1]

(Examples 4 and 5, Comparative Examples 4 and 5) Example 1
After knitting each of the fibers obtained in Steps 1 and 2, a 75-denier 24-filament polybutylene terephthalate (PBT) fiber, and a 75-denier 24-filament polyethylene terephthalate (PET) fiber, the moisture absorption performance was evaluated by the method described above. . Table 2 shows the obtained results.

[0035]

[Table 2]

[0036]

The polymer blend fiber of the present invention is a polymer blend fiber which is inexpensive and has both excellent mechanical properties of polyester fiber and excellent feeling of cellulose ester fiber. It has excellent dyeing properties and hygroscopicity, and can be used in various fields including clothing.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing a cross section of a polymer blend fiber of the present invention in a direction perpendicular to a fiber axis.

Claims (6)

[Claims] 1. A fiber comprising, as components, 5 to 60% by weight of a cellulose ester containing 15 to 35% by weight of a cellulose ester plasticizer and 95 to 40% by weight of a polyester. A polymer blend fiber wherein polyester is separated into sea-like and cellulose ester is separated into island-like in a cross section perpendicular to the fiber axis. 2. The cellulose ester having an acetylation degree of 45 to 5
The polymer blend fiber of claim 1 wherein the fiber is 9.5% cellulose diacetate. 3. The plasticizer content of the cellulose ester relative to the cellulose ester is 21 to 35%.
Or the polymer blend fiber according to 2. 4. The polymer blend fiber according to claim 1, wherein the melting point of the polyester is 240 ° C. or lower. 5. The polymer blend fiber according to claim 1, which satisfies the following formula (1). DS × √DE ≧ 10 (1) Here, DS indicates fiber strength, and DE indicates elongation at break. 6. The moisture absorption rate at 20 ° C. and a relative humidity of 65% is 0.5% or more, and at 30 ° C. and a relative humidity of 90%.
The polymer blend fiber according to any one of claims 1 to 5, which has a moisture absorption of 1.0% or more.