JP3078372B2 - Polyethylene porous fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene-based porous fiber, and more particularly to a polyethylene-based porous fiber useful as an adsorbent material and a reserve substrate.

[0002]

2. Description of the Related Art Conventionally, porous fibers include acrylic porous fibers in which voids are formed during wet spinning, and polyester fibers in which a dissolvable component is added and the component is alkali-eluted after melt spinning. As described in JP-B-56-52123, polypropylene or polyethylene is melt-spun into a hollow fiber under a high draft, orientation is advanced by heat treatment, and it is stretched in multiple stages. Polyolefin hollow porous fibers and the like having slit-shaped pores produced by the above method are known. However, technical problems described below have been pointed out for these porous fibers.

[0003]

That is, the above-mentioned acrylic porous fibers and polyester porous fibers are fibers having a thickness which can be applied to a general textile machine such as a card machine. Due to the characteristics derived from these manufacturing methods, the porosity, specific surface area, porosity of the fiber surface, and pore size are small, so even when used for adsorbent materials or reserve base materials, the amount of adsorbed liquid and liquid retention are insufficient, and the adsorbing speed. , Slow absorption rate
In terms of the material, there is a problem that it is attacked by an organic solvent or a strong alkali.

On the other hand, polyolefin hollow porous fibers have almost no problem in chemical resistance, but it is difficult to obtain fibers having a denier of 50 denier or less which can be applied to ordinary textile machines. When the fiber is thick, the cloth can be formed only by weaving the cloth with continuous filaments. However, as an adsorbent, a fine-grained material such as a nonwoven fabric is suitable, but if the fiber is thick, it can only be used as a cloth, and the cloth to be adsorbed passes through the weave, resulting in poor adsorption efficiency. The adsorption performance of the fiber could not be used effectively.

The porous fiber obtained by the production method described in Japanese Patent Publication No. 56-123123 is one in which elongated slit-like pores are dispersed on the fiber surface, and the cross section is from the fiber surface to the center. The pores penetrate almost linearly. Therefore, for example, even if an attempt is made to adsorb or encapsulate a particulate substance, it cannot be applied to particles having a particle size larger than the slit width. That is, it can be used substantially only for adsorbing fine particles of 0.1 μm or less.

Further, according to the production method disclosed in the above-mentioned publication, it is possible to increase the slit width by lowering the draw ratio, but this reduces the porosity of the fiber,
As a result, there is a problem that a large amount of particles cannot be adsorbed. The present invention has been made in view of such conventional problems, and has as its object the purpose of the present invention is to have excellent chemical resistance capable of coping with various adsorbed substances, and to increase the specific surface area and porosity. Another object of the present invention is to provide a polyethylene-based porous fiber which has a large surface porosity and can be processed by a normal fiber machine.

[0007]

In order to achieve the above object, the present invention provides a melt index of 0.3 to 20 g / m.
A fiber body made of high-density polyethylene for 10 minutes, paraffin wax was mixed with the high-density polyethylene under melting, and melt-spun with an extruder at a draft rate of 200 or less,
Stretching, fixed-length heat treatment, is formed by removing the paraffin wax after crimping, wide width, a narrow longitudinally
It has a double-hole shape that repeats at orthogonal fiber cross-sections.
When the specific surface area of the fiber body is 20 m ² / g or more, the ratio of the pores to the fiber body is 20% or more, and the denier of the fiber body is 50 or less. There is a feature.

[0008] The polyethylene-based porous fiber of the present invention is filled with a layer of paraffin wax between polyethylene crystals during spinning, expands these crystals by hot stretching, and extracts paraffin wax after heat treatment and mechanical crimping. A large number of small and large pores are formed between the expanded crystals. Therefore, the obtained fiber has a very special structure due to its manufacturing method. The lamellar crystals are deformed zigzag by the hot stretching, and then the layer of paraffin wax filled between these crystals is extracted and removed.
In the cross section of the fiber perpendicular to the longitudinal direction, while the state where the width is repeatedly increased and decreased, pores are formed from the surface to the inside like a hole of a loofah.

Therefore, the ratio of the pores to the fiber main body (hereinafter referred to as porosity) is high, and the fiber has a large specific surface area. The fiber of the present invention has a pore ratio of 2 to the fiber body.
At 0% or more, the specific surface area of the fiber main body is limited to 20 m ² / g or more. The reason is that if the porosity is less than 20%, the active ingredient is not sufficiently retained as a reserve base material, and a large amount of substances cannot be adsorbed as an adsorbing material. Also,
If the specific surface area of the fiber main body is less than 20 m ² / g, the amount of adsorption is small when adsorbing the substance to be adsorbed in a liquid, gaseous or solution, and it is unsuitable as an adsorbing material.

Further, the reason why the weight denier of the fiber body is limited to 50 denier or less is that if it exceeds 50 denier, the permeability of the card machine becomes extremely poor, and it becomes possible to make the product as fine as a nonwoven fabric. Because it is gone.

[0011]

According to the polyethylene-based porous fiber having the above constitution, as is apparent from the examples described below, it has excellent chemical resistance and can contain and hold a large amount of active ingredients.
A fabric having high adsorption performance can be obtained.

[0012]

Hereinafter, embodiments of the present invention will be described.
The present invention is not limited only to these examples.
The methods for measuring the physical properties shown in the examples are shown in advance.

Porosity The porosity was calculated from the diameter denier (D1) calculated from the fiber diameter and the weight denier (D2) calculated from the weight according to the following equation. D1 = cross-sectional area of fiber (cm ² ) × 9 × 10 ⁵ cm × density (g / cm ³ ) D2 = weight of fiber of 9000 m Porosity (%) = (diameter denier−weight denier) / diameter denier × 100 ratio Surface area Measured by the nitrogen gas adsorption method specified in JIS Z 8830.

Water absorption 3 g of a fiber was filled in a tea bag, immersed in methanol for 10 minutes, immersed in water for 60 minutes, and centrifugally dehydrated for 3 minutes to obtain a weight (W ₁ ), which was calculated by the following equation. Water absorption (%) = (W ₁ -3) / 3 × 100 Surfactant adsorption amount 10 g of fiber is a 2% aqueous solution of potassium salt of C ₈ alkyl phosphate (UN683 manufactured by Takemoto Yushi Co., Ltd .: 4.5 parts by weight and water 95.5 parts by weight of the mixture) for 10 minutes,
Dehydrated and dried, and the increased weight per 10 g of fiber is adsorbed (g)
And

Example 1 100 parts by weight of HDPE (manufactured by Mitsui Petrochemical Co., Ltd .: Hizex 2200J) having an MI value of 5.5 g / 10 min.
A raw material obtained by mechanically mixing 100 parts by weight of paraffin wax (manufactured by Nippon Oil Co., Ltd .: 145 ° paraffin) was set to 145 ° C. to 180 ° C. by attaching a nozzle having a screw diameter of 25 mm and 0.40 mm φ × 160 holes. And the winding speed V1 is 200 m / m.
In, an undrawn yarn of 10 denier at a spinning draft rate of 80 was obtained.

Twelve multifilaments comprising the obtained undrawn yarns were collected and drawn using a roller drawing machine at 110 ° C. at an overall draw ratio of 3.0 and a strain rate of 40% / min. . Subsequently, in a state where the fiber is wound around a paper tube, the fiber is subjected to a constant-length heat treatment in an oven at 110 ° C. for 1 hour, further subjected to mechanical crimping to give a crimp of 15 pieces / inch, and cut into 51 mm. After forming staple fibers, they were immersed in hexane at room temperature to extract paraffin wax.

The obtained fiber was solid and had a porosity of 45%, a specific surface area of 39 m ² / g, and a weight denier of 2.3 denier. The amount of surfactant adsorbed on the polyethylene-based solid porous fiber was 0.78 g, and the water absorption was 105%. The staple fiber was examined for card passability and found to be good. Further, the pore diameter on the fiber surface was 0.5 to 1 μm.

Example 2 60 parts by weight of HDPE (STAFLEN E809F, manufactured by Nippon Petrochemical Co., Ltd.) having a MI value of 0.9 g / 10 minutes, and 40 parts by weight of paraffin wax (145 ° paraffin, manufactured by Nippon Oil Co., Ltd.) And a draft ratio of 180% and a draw ratio of 3.0 were used, and the other manufacturing conditions were the same as in Example 1 to produce a porous fiber. The physical properties of the obtained fiber are shown in FIG.

Comparative Example 1 This is the undrawn yarn of Example 1, and the physical properties of the undrawn yarn are shown in FIG.

Comparative Example 2 Compared to Example 1, the stretching ratio was 4.5 times and the strain rate was 3
The porous fiber was manufactured in the same manner as in Example 1 except that the manufacturing conditions were changed to 500. The physical properties of the obtained fiber are shown in FIG.

Reference Example Reference Example 1 is a commercially available polyester-based porous fiber (Welkey, trade name, manufactured by Teijin Limited), and Reference Example 2 is a commercially available acrylic porous fiber (Akwaron, manufactured by Kanebo Co., Ltd.).

As is clear from the results shown in FIG.
Fibers have high water absorption and a large amount of surfactant adsorbed,
It was suitable as an adsorbing material and a reserve base material. However, the fiber of Comparative Example 1 having a low porosity was not superior in water absorption than the fiber of Reference Example 1, which was a conventional polyester-based porous fiber. Further, the fiber of Comparative Example 2 having a specific surface area outside the claims of the present invention has a large specific surface area as compared with the commercially available fiber of Reference Example 2, but the amount of adsorbed surfactant is not so large as expected and is excellent. I couldn't say.

Example 3 100 parts by weight of HDPE (HIZEX 2200J manufactured by Mitsui Petrochemical Co., Ltd.) having a MI value of 5.5 g / 10 min and 100 parts by weight of paraffin wax (145 ° paraffin manufactured by Nippon Oil Co., Ltd.) Mechanically mixed raw materials,
A nozzle having 30 circular arc-shaped openings with two closed circular slits having a width of 0.2 mm, an inner diameter of 0.9 mmφ, and an outer diameter of 1.3 mmφ was attached to an extruder having a screw diameter of 25 mm. It was fed to a melt spinning machine set at ~ 180 ° C to obtain a 29 denier undrawn yarn at a take-up speed V1 of 200 m / min and a spinning draft rate of 170.

Twenty obtained undrawn yarns were collected, and the strain density was 40% / at 110 ° C. using a roller drawing machine.
The film was stretched and wound under the condition of a stretching ratio of 3.0 times. The fiber is wound in a paper tube and placed in an oven at 110 ° C for 1 hour.
The heat treatment was performed for a fixed length of time. Subsequently, this was further mechanically crimped to give a crimp of 15 pieces / inch, cut into 51 mm to form staple fibers, and immersed in hexane at room temperature to extract paraffin wax.

The obtained porous fiber has a denier of 6.1.
It is a hollow fiber having an outer diameter of 40 μm and an inner diameter of 11 μm, a porosity of 40%, a specific surface area of 36 m ² / g, a water absorption of 81%, and a surfactant adsorption of 0.65 g. ,
It had sufficient performance.

[Brief description of the drawings]

FIG. 1 is a table showing physical property values of Examples, Comparative Examples, and Reference Examples of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D06M 11/00-13/535 D01F 6/04 D01F 6/46

Claims (1)

(57) [Claims] 1. A melt index of 0.3 to 20 g /
A fiber body made of high-density polyethylene for 10 minutes, paraffin wax was mixed with the high-density polyethylene under melting, and melt-spun with an extruder at a draft rate of 200 or less,
Stretching, fixed-length heat treatment, is formed by removing the paraffin wax after crimping, wide width, a narrow longitudinally
It has a double-hole shape that repeats at orthogonal fiber cross-sections.
When the specific surface area of the fiber body is 20 m ² / g or more, the ratio of the pores to the fiber body is 20% or more, and the denier of the fiber body is 50 or less. A polyethylene-based porous fiber, characterized in that: