JP2002309445A - Antibacterial polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antibacterial polyester fiber having good spinnability, good antibacterial activities and excellent color, and hardly causing discoloration (coloring) even if the fiber is subjected to an alkali treatment. SOLUTION: This polyester fiber containing an inorganic antibacterial agent constituted of a phosphoric acid salt carrying silver, and titanium dioxide is regulated so that the content of the antibacterial agent in the fiber may be 0.5-5.0 wt.%. and the content of the titanium oxide in the antibacterial agent may be 30-80 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial polyester fiber which has a small discoloration even after being subjected to an alkali treatment and contains a silver-based antibacterial agent and is suitable for the field of clothing.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have been widely used because of their excellent mechanical and chemical properties. In recent years, various antibacterial fibers have been put into practical use due to the diversification of consumer values and the increasing awareness of hygiene.

[0003] Many methods have been proposed for imparting antibacterial and deodorant properties to polyester fibers. As a method for immobilizing the antibacterial agent on the fabric by post-processing, there are a method using a silicon-based quaternary ammonium salt and a method using an aliphatic quaternary ammonium salt.

However, since these have an antibacterial agent adhered to the fiber surface, they have a drawback that they fall off due to washing, friction, and abrasion, resulting in a decrease in antibacterial performance. Further, as described in JP-A-56-148965, a method of bonding silver ions to a fiber having an ion-exchange group on the surface and a method of bonding transition metal ions to a similar fiber have been proposed. . However, these require the introduction of ion-exchange groups to the fiber surface, and are effective for acrylic fibers but are unsuitable for polymers having few functional groups such as polyester fibers.

[0005] In order to solve the above problems, a number of methods for obtaining antibacterial polyester fibers by adding powder having antibacterial properties to polyester have been proposed so far, as disclosed in JP-A-59-133235. JP-B-63-54103 and JP-B-63-175117 disclose antibacterial fibers obtained by mixing antibacterial zeolite (silver zeolite) with polyester before melt spinning and melt spinning. Have been.

[0006] Synthetic fibers containing antimicrobial zeolites have good antimicrobial properties and excellent durability. However, such fibers can be treated with an alkali reducing agent, which is a means of improving the texture of polyester, to reduce the antimicrobial components. However, there is a drawback that the silver used in the above-mentioned method is oxidized and discolored (colored), so that its use in applications requiring whiteness is restricted.

[0007] By reducing the amount of silver in the fiber, it is possible to suppress discoloration during alkali weight reduction processing. However, since it does not have sufficient antibacterial properties, it is difficult to handle in applications where alkali weight reduction processing is performed. There are drawbacks.

Japanese Patent Application Laid-Open No. 4-50367 discloses a method for improving the whiteness of fibers by treating antibacterial polyester fibers containing an antibacterial agent using silver in combination with another metal with sodium percarbonate. ing. However, this method requires a special post-processing step, and thus has the disadvantage of increasing the manufacturing cost and reducing the productivity. Also,
Here, the effect of discoloration on alkali is not mentioned, and it does not improve discoloration after alkali reduction processing.

Accordingly, the present inventors have disclosed in JP-A-11-158730 a core-sheath type composite antibacterial polyester fiber having improved discoloration after alkali reduction by containing a silver compound as an antibacterial agent in the core. Has been proposed. However, this fiber must be manufactured using a composite-type spinning machine, which complicates the manufacturing process.In addition, in order to exert its effect sufficiently, the core-sheath ratio of the fiber and the alkali weight reduction ratio are limited. , Was difficult to control.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, has good spinnability, can be obtained at low cost, and has little discoloration (coloring) even after alkali treatment.
An object of the present invention is to provide an antibacterial polyester fiber having excellent color tone.

[0011]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention. That is, the present invention is a polyester fiber containing an inorganic antibacterial agent composed of a phosphate carrying silver and titanium dioxide, wherein the content of the antibacterial agent in the fiber is 0.5 to
5.0 mass%, the content of titanium dioxide in the antibacterial agent is 30 to 80
The present invention provides an antibacterial polyester fiber characterized by its mass%.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The antibacterial polyester fiber of the present invention contains a silver-based antibacterial agent in the fiber, and even if the antibacterial agent is uniformly contained in the entire fiber, a part of the fiber cross section is used. For example, it may be included in one component of a composite yarn such as a core-sheath type or a side-by-side type. In particular, it is preferable to have a structure in which a part of the antibacterial agent component is exposed on the fiber surface. Further, the shape of the fiber may be any of a round cross section, an irregular cross section, and a hollow cross section.

The polyester constituting the fiber of the present invention is:
There are polyalkylene terephthalate, polyalkylene naphthalate and the like. Specifically, polyethylene terephthalate (PET) and polytrimethylene terephthalate (P
TT) and polybutylene terephthalate (PBT) are preferably used.

The polyalkylene terephthalate and the polyalkylene naphthalate may contain a copolymer component as long as the performance peculiar to the polyester is not impaired. Examples of the copolymer component include 5-sodium sulfoisophthalic acid and isophthalate. Acid, phthalic anhydride, aromatic dicarboxylic acid components such as naphthalenedicarboxylic acid, adipic acid,
Aliphatic dicarboxylic acid components such as sebacic acid, glycol components such as diethylene glycol, propylene glycol, 1,4-cyclohexyldimethanol, and alkylene oxide adducts of bisphenol A; hydroxycarboxylic acid components such as 4-hydroxybenzoic acid and ε-caprolactone And the like.

The most important feature of the present invention is that the fiber contains an antibacterial agent comprising a phosphate carrying silver and titanium dioxide. Thereby, it is possible to reduce the possibility that silver in the antibacterial agent is discolored due to alkali when the fiberized fabric is alkali-treated, and causes discoloration of the entire fabric. That is, the discoloration of silver is concealed by titanium dioxide, so that the discoloration of the fiber can be suppressed without impairing the antibacterial power of silver.

The phosphate constituting the antibacterial agent of the present invention is:
Zirconium phosphate, calcium phosphate, or a combination thereof is preferred, and the amount of silver carried is preferably in the range of 2 to 20% by mass based on the phosphate. If the amount of silver is less than this range, it is difficult to obtain sufficient antibacterial properties. If the amount is more than this range, the color tone after the alkali treatment of the fiber becomes poor, and it is difficult to obtain the effects intended by the present invention.

The amount of titanium dioxide in the antibacterial agent must be in the range of 30 to 80% by mass based on the whole antibacterial agent. The antibacterial agent used in the present invention is one in which titanium dioxide is compounded around a phosphate unit carrying silver at a micro level, thereby discoloring the fiber without impairing the antibacterial power of silver as described above. Can be suppressed. If the amount of titanium dioxide is less than this range,
The effect of suppressing the discoloration of the fiber is poor and a high whiteness fabric cannot be obtained, and when the amount of titanium dioxide is larger than this range, the dissolution of silver is inhibited and sufficient antibacterial performance cannot be exhibited, which is not preferable. .

Further, the amount of the antibacterial agent contained in the fiber is
It is necessary to be 0.5 to 5.0% by mass based on the mass of the fiber. If the amount of the antibacterial agent is less than this range, sufficient antibacterial performance cannot be obtained, and if the amount of the antibacterial agent is larger than this range,
Operational troubles are likely to occur, such as a decrease in fiber strength, causing yarn breakage during processing such as weaving and knitting.

The antibacterial fiber of the present invention can prevent discoloration before and after the alkali treatment by containing the above antibacterial agent. Specifically, the color difference before and after the alkali treatment ( ΔE) is preferably 5.0 or less, and more preferably 2.0 or less.

The term “alkali treatment” used herein refers to the use of an antibacterial polyester fiber of the present invention obtained by tubular knitting.
It means that it is dried at 70 ° C. for 30 minutes and then treated in a 10% sodium hydroxide solution adjusted to 70 ° C. for 100 minutes. In the case of PET, the weight loss rate at this time is usually 10 to 30.
%.

The color difference before and after the alkali treatment (ΔE)
Describes the color tone (L, a, b values) of a cylindrical knitted fabric before and after alkali treatment by a color difference meter manufactured by Minolta Co., Ltd.
It is measured by CR-100 and calculated by the following formula. ΔE = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2 ΔL ^* : difference in L value before and after alkali treatment Δa ^* : difference in a value before and after alkali treatment Δb ^* : alkali Difference of b value before and after processing

When the color difference (ΔE) exceeds 5.0, it is mixed with ordinary polyester and other materials, woven and knitted, and then subjected to alkali weight reduction processing and dyeing processing. It gets worse and dull. In addition, if the discoloration (coloring) during the alkali weight reduction processing is severe, other materials may be discolored (colored) due to the components released from the antibacterial fiber during the weight reduction processing, and dyeing is performed in the subsequent dyeing processing. Spots and poor coloring are unfavorable.

Further, the antimicrobial polyester fiber of the present invention may contain, for example, an ultraviolet absorber, an antistatic agent, a pigment, titanium oxide, silicon dioxide, etc. during the fiber production, as long as it does not inhibit the expression of antimicrobial properties. It may be added, or an anti-mite agent, a deodorant, or the like may be added to the fiber.

The antimicrobial polyester fiber of the present invention can be produced by a conventional method using a melt spinning apparatus. The antimicrobial agent to be contained may be added at the time of polymerizing the polymer. It may be added at the time of polymer melting during the process, and may be uniformly kneaded and dispersed. Further, a master polymer containing a high concentration of an antibacterial agent and a base polymer may be kneaded and used, and may be contained in the fiber. It may be contained therein.

[0025]

When the antibacterial polyester fiber of the present invention is used,
It is possible to provide a polyester fiber having good color tone without discoloration (coloring) after alkali treatment and having good antibacterial properties. Although the mechanism of discoloration prevention of the antibacterial agent used in the present invention is not clear, it is presumed that titanium dioxide masks discoloration of silver. In addition, since the mixing ratio of titanium dioxide does not affect the elution of silver, the antibacterial property is not impaired.

[0026]

Next, the present invention will be described specifically with reference to examples. The measurement and evaluation of the characteristic values in the examples are as follows. (A) Evaluation of antibacterial activity (bacteriostatic activity value) The evaluation was carried out according to the unified test method of the Council for Textile Sanitation Processing (JAFET). A sample dried in a clean bench after sterilization (approx.
0.4 g of an 18 mm square test piece was subjected to high-pressure steam sterilization and ice-cooled, and the viable cell count was reduced to 1/20 with a 1/20 concentration nutrient broth.
0.2 ml of the test bacterial suspension adjusted to ± 0.3 × 10 5 cells / ml is inoculated so as to uniformly soak the whole specimen, and a sterilized cap is fastened. This is cultured at 37 ± 1 ° C. for 18 hours. The number of viable bacteria after the culture is measured. As the test bacterium, Staphylococcus aureus ATCC 6538P was used.
The bacteriostatic activity value, which is an indicator of antibacterial activity, was calculated by the following method. Bacteriostatic activity value: LogB-LogC However, the test must meet the conditions (LogB-LogA)> 1.5. A: Average number of bacteria recovered immediately after inoculation of the standard cloth B: Average number of bacteria recovered after 18 hours of cultivation of the standard cloth C: Average value of number of bacteria recovered after 18 hours of cultivation of the work cloth Used those specified in the processing effect evaluation test manual for antibacterial and deodorized products. (B) Alkali weight loss rate The mass after drying the sample before alkali treatment at 70 ° C. for 30 minutes is defined as [B], and the sample after alkali treatment is washed with distilled water,
The mass after drying at 70 ° C. for 30 minutes was defined as [A], and the alkali loss rate was calculated by the following equation. Alkali weight loss rate (%) = {(BA) / B} × 100 (c) Color difference before and after alkali treatment (ΔE) Measured by the method described above.

Example 1 PET having an intrinsic viscosity (measured from a value measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent) using a commonly used melt spinning machine stand was 0.69. Melt spinning was performed using the chips. At that time, an antibacterial agent in which zirconium phosphate carrying silver at 10% by mass and titanium dioxide were mixed at a mass ratio of 30/70 when the polymer was melted was added at 1.0% by mass with respect to the whole polymer. After the melt spun yarn is taken up by a roller having a surface speed of 3500 m / min, it is subsequently supplied to a drawing roller, and taken up by a take-up machine having a take-up speed of 5000 m / min. Obtained.
At this time, a fiber having good elongation characteristics could be obtained with good operability. Next, this fiber was made into a 1 g tubular knitted fabric,
It was dried at 0 ° C. for 30 minutes and subjected to an alkali treatment in a 10% sodium hydroxide solution adjusted to 70 ° C. for 100 minutes. Thereafter, the alkali is washed with distilled water,
And dried. At this time, the alkali weight loss rate was 19.1%.

Examples 2 to 6 and Comparative Examples 1 to 5 The same procedure as in Example 1 was carried out except that the content of the antibacterial agent and the content of titanium dioxide in the antibacterial agent were changed so as to have the values shown in Table 1. Was.

Table 1 shows the evaluation results of the antibacterial properties and color difference (ΔE) of the fibers obtained in Examples 1 to 6 and Comparative Examples 1 to 5.

[0030]

[Table 1]

As is clear from Table 1, the fibers of Examples 1 to 6 all had good antibacterial properties and good color difference before and after the alkali treatment. In addition, fibers were obtained with good operability. On the other hand, the fiber of Comparative Example 1 had insufficient antibacterial properties because the content of the antibacterial agent in the fiber was small, and the fiber of Comparative Example 2 had too high an antibacterial content in the fiber, so that the yarn was spun at the time of spinning. There were many cuts and the color change after the alkali treatment was large. The fiber of Comparative Example 3 had a large change in color tone after alkali treatment because the ratio of titanium dioxide in the antibacterial agent was too small,
The fiber of Comparative Example 4 had insufficient antibacterial properties because the ratio of titanium dioxide in the antibacterial agent was too large. Since the fiber of Comparative Example 5 did not contain titanium dioxide in the antibacterial agent, the color tone change after alkali treatment was extremely large.

[0032]

The antimicrobial polyester fiber of the present invention is an antimicrobial polyester fiber having good antimicrobial properties, little discoloration (coloring) even after alkali treatment, and excellent in color tone. Further, it can be obtained with good operability at low cost. Therefore, it can be suitably used for clothing requiring whiteness and antibacterial and deodorant properties, such as medical lab coats, kappa garments for restaurants and the like. Further, it can be suitably used for women's blouses, school children's shirts and the like.

Claims (2)

[Claims] 1. A polyester fiber containing an inorganic antibacterial agent composed of a phosphate supporting silver and titanium dioxide, wherein the content of the antibacterial agent in the fiber is 0.5 to 5.0% by mass,
An antibacterial polyester fiber, wherein the content of titanium dioxide in the antibacterial agent is 30 to 80% by mass. 2. The color difference (ΔE) before and after the alkali treatment is 5.0.
The antibacterial polyester fiber according to claim 1, which is: