JPH09117622A - Antimicrobial electret material and filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent antimicrobial properties and the outstanding performance of an electret, characteristic of high charge stability. SOLUTION: An antimicrobial electret material is a synthesized organic polymer with a volume resistivity of 10<13> Ω.cm or more, containing a heat stabilizer and an arsenic compound with a phenoxy group. In addition, the surface charge density of this polymer is 1×10<-10> coulomb/cm<2> or more. Further, the filter has at least, a part of a filter medium formed of the antimicrobial electret material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antibacterial electret material and a filter having both antibacterial properties and electret properties, and particularly to an air cleaner,
The present invention relates to an extremely useful material as a filter for a vacuum cleaner or the like.

[0002]

2. Description of the Related Art As an antibacterial electret material, as disclosed in Japanese Patent Laid-Open No. 62-42716, there is a filter material obtained by applying an antibacterial treatment with an antibacterial agent to a fiber surface and then electretizing. Various proposals have been made in which an electret-processed fiber sheet and an antibacterial drug treatment sheet are superposed.

[0003]

However, since the former material uses an organic antibacterial agent and a surfactant that disperses the same on the fiber surface, the volume resistivity of the surface becomes small, and therefore the electretization treatment is performed. However, there are drawbacks that the obtained electric charge is small and the charge decays quickly. Also,
The latter material has the disadvantages of poor workability to the unit and large airflow resistance when used in filters, for example, and also has poor filter performance because the entire material is not electretized. There was also a drawback. In view of such conventional drawbacks, the present invention intends to provide an antibacterial electret material and a filter having both excellent antibacterial properties and electret properties excellent in charge stability.

[0004]

The present invention employs the following means in order to solve the above problems. That is, the antibacterial electret material of the present invention has a volume resistivity of 1
A synthetic organic polymer of 0 ¹³ Ω · cm or more, which contains a heat stabilizer and an arsenic compound having a phenoxy group, and has a surface charge density of 1 × 10 5.
^-10 coulomb / cm ² or more, and the filter of the present invention is characterized in that at least a part of the filter medium is composed of such an antibacterial electret material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain a material having both antibacterial properties and electret properties, the present invention has been earnestly studied and found that a specific compound as an antibacterial agent to be contained in an electretized synthetic organic polymer. By adopting it and coexisting with a heat stabilizer, it was surprisingly clarified that it provides a material having a high surface charge density, hard to decay, easy to process into a unit, and yet excellent in antibacterial performance. It was done.

That is, the present invention is specifically, an organic polymer having a volume resistivity of 10 ¹³ Ω · cm or more, such as polyolefin, polyester, fluororesin, acrylic resin,
In a polyamide resin or the like, 0.01 to 2% by weight of a heat stabilizer is allowed to coexist as an electret stabilizer, and
As an antibacterial agent, an arsenic compound having a phenoxy group was added to 0.0
It is characterized by containing 05 to 0.5% by weight.

A heat stabilizer is preferably used as the electret stabilizer, and the heat stabilizer is not particularly limited, but a hindered amine type, a nitrogen-containing hindered phenol type, a metal salt hindered phenol type is used. It is preferable to use a heat stabilizer selected from the group consisting of phenol type, sulfur type and phosphorus type. For example, in the case of hindered amines, poly [{(6
-(1,1,3,3-tetramethylbutyl) imino-
1,3,5-triazine-2,4-diyl} {(2,
2,6,6-tetramethyl-4-piperidyl) imino}
Hexamethylene ｛(2,2,6,6-tetramethyl-4
-Piperidyl) imino}], dimethyl succinate-1-
(2-hydroxyethyl) -4-hydroxy-2,2,
6,6-Tetramethylpiperidine polycondensate, 2- (3,
5-di-t-butyl-4-hydroxybenzyl) -2-
For example, bis (1,2,2,6,6-pentamethyl-4-piperidyl) n-butylmalonate can be used.

In the case of a nitrogen-containing hindered phenol type, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid or 1,3,5 -Tris (3,5-di-t-
Butyl-4-hydroxybenzyl) isocyanuric acid or the like can be used.

Further, among the metal salt hindered phenol compounds, 3,5-di-t-butyl-4-hydroxy-benzyl-monoethylphosphonate calcium salt, 3,5
A nickel salt of -di-t-butyl-4-hydroxy-benzyl-monoethylphosphonate, a magnesium salt of the above compound, or the like can be used.

Further, in the phenol type, 1, 3,
5-trimethyl-2,4,6-tris (3,5-di-t
-Butyl-4-hydroxybenzyl) benzene, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl- (3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate and the like can be used.

As the sulfur type, distearyl thiodipropionate, dilauryl thiodipropionate and the like can be used.

As the phosphorus type, distearyl pentaerythritol diphosphate and the like can be used.

As the antibacterial agent, an arsenic compound having a phenoxy group is used. For example, 10,10'-oxybisphenoxaarsine, 10,10'-thiobisphenoxaarsine, 10,10'-oxybisphenarsazine and 1
0,10'-thiobisphenalsazine can be used. Particularly, 10,10'-oxybisphenoxaarsine is preferable.

A polymer material containing the above additives is formed into a fiber, a woven fabric, a knitted fabric or a non-woven fabric. Such molding may be carried out by the conventionally known ordinary molding methods.

Then, these materials are electretized in a high DC voltage to obtain an electret material having a high charge density. Such electretization processing can also be performed by a conventionally known method.

In the present invention, as the electret material, one having a surface charge density of 1 × 10 ^-10 coulomb / cm ² or more is used. Further, according to the knowledge of the present inventors, a sheet such as a nonwoven fabric or a woven fabric which has been electretized has a surface charge density of 2 × 10 ⁻¹⁰ coulomb / cm ² or more, and the upper limit thereof is determined by the present inventors. According to the knowledge, it is generally about 1 × 10 ⁻⁸ coulomb / cm ² . Also,
It is particularly preferable to use a sheet whose front and back surfaces have different electric polarities.

In order to exhibit the electret property while having the antibacterial property, it is important that the electret stabilizer and the antibacterial agent coexist. That is, the electret stabilizer is preferably present in an amount of 0.01% by weight, from the viewpoint of electret property, and since it is not effective even if it is too much, it is preferably present in the range of 2% by weight or less. On the other hand, the concentration of the antibacterial agent is about 0.00 although it varies depending on the type of the target bacteria and the environment in which the antibacterial electret material is used.
It is preferable to exist in the range of 5% by weight or more and 0.2% by weight or less. More preferably 0.01% by weight to 0.0
It is in the range of 5% by weight.

The electret material thus obtained is
Since it has both the electret property and the antibacterial property, it is a suitable material especially for applications such as a filter, which is required to have both a dust collecting function and a bacteria propagation preventing function due to the dust. When such a material is used for a filter, a non-woven fabric is preferable, and a melt-blown non-woven fabric is particularly preferable because it is easy to form ultrafine fibers.

The electret material according to the present invention has an excellent electret property, but this electret property exerts a remarkable effect by the charges trapped by the electret stabilizer coexisting in the resin.
These electric charges have a characteristic of maintaining a stable electric charge even when environmental conditions, humidity and temperature change. On the other hand, the antibacterial property in the present invention exhibits an effect of preventing reproduction against bacteria and mold due to the broad antibacterial performance of the arsenic compound having a phenoxy group kneaded in the resin. Therefore, the electret material of the present invention can be used for applications such as filters, packaging materials, agricultural materials, wipers, various cover materials, medical materials and the like.

The surface charge density Q (coulomb / cm ² ) of the electret material of the present invention is determined by sandwiching the electret material with two metal plates connected via a capacitor having a capacity C (farad). It is a value obtained by Q = C × V / S from the voltage V (V) measured between both terminals and the surface area S (cm ² ) of the electret material.

The antibacterial property is evaluated by an antibacterial property test according to ZIS-L1902 (Halo method).

[0022]

EXAMPLES Hereinafter, further details will be described based on examples.

Example 1 3,5-di-t-butyl-4-hydroxy-benzyl-comprising polypropylene having a volume resistivity of 2 × 10 ¹⁶ Ω · cm and being a metal salt hindered phenol as an electret stabilizer. 0.2% by weight of calcium salt of monoethylphosphonate and phenol-based pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate] was contained in an amount of 0.1% by weight, and a commercial melt-blown nonwoven fabric having a basis weight of 20 g / m ² containing 0.05% by weight of a commercially available 10,10′-oxybisphenoxaarsine as an antibacterial agent was produced. .

The non-woven fabric was treated in a voltage of +30 KV for 1 minute to be electretized. The surface charge of non-woven fabric is 5 ×
At 10 ⁻¹⁰ coulomb / cm ² , the polarities of the front and back surfaces were separated into positive and negative. In an antibacterial test using Staphylococcus aureus, a halo of 3 mm was recognized and it was antibacterial.

The electretized non-woven fabric has a filter collection performance of 88% with a collection efficiency of 0.3 micron particles at a wind speed of 1.5 m / min, and was used as a filter medium for an air cleaner for 4 months indoors. No mold was found on the filter and no odor was found.

On the other hand, the melt-blown nonwoven fabric which was not electretized without adding the electret stabilizer and antibacterial agent used in the comparison showed no antibacterial property in the antibacterial property test, and the collection efficiency as a filter was 25. %Met. An odor was observed after 4 months of use as an air purifier, and mold was generated on the filter.

Example 2 A melt-blown non-woven fabric having a basis weight of 50 g / m ^{2 made} of polypropylene having a volume resistivity of 2 × 10 ¹⁶ Ω · cm, and 0.4 wt% of a sulfur-based distearyl thiodipropionate as an electret stabilizer, and an antibacterial agent. Commercially available 10,10
'-Oxybisphenoxaarsine was added at 0.03% by weight.

This nonwoven fabric was electretized for 1 minute at a voltage of -30 KV. The surface charge density of the obtained electret nonwoven fabric was 7 × 10 ^-10 coulomb / cm ² , and a halo of 1 mm was recognized in the antibacterial property test using Klebsiella pneumoniae, indicating that it had antibacterial properties.

As a electret stabilizer used for comparison, sulfur-based distearyl thiodipropionate of 0.4 was used.
The surface charge density of the electret meltblown nonwoven fabric obtained by electretizing a meltblown nonwoven fabric with a basis weight of 50 g / m ² with no added antibacterial agent was 7 × 10 ^-10 coulomb / cm ² , but antibacterial test No halo was observed in the test and there was no antibacterial property.

Example 3 A spunbonded non-woven fabric having a basis weight of 100 g / m ² and made of polypropylene having a volume resistivity of 2 × 10 ¹⁶ Ω · cm was used as a hindered amine electret stabilizer with poly [{(6- (1,1,1, 3,3-Tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl}
{(2,2,6,6-tetramethyl-4-piperidyl)
0.1% by weight of imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] and phenol-based pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] was added in an amount of 0.1 wt.
5 wt% was added.

This non-woven fabric was electretized for 1 minute in +25 KV voltage. The surface charge density of the obtained electret non-woven fabric was 3 × 10 ^-10 coulomb / cm ² , and a halo of 1 mm was recognized in the antibacterial property test using Klebsiella pneumoniae, and it was antibacterial.

For comparison, a polypropylene spunbonded non-woven fabric containing 0.05% by weight of an antibacterial agent without adding an electret stabilizer was electretized under the same conditions to obtain an electretized spunbonded non-woven fabric. Antibacterial property was confirmed in the antibacterial property test, but the surface charge density was 0.4.
It was as low as × 10 ^-10 coulomb / cm ² and was hardly electretized.

[0033]

EFFECT OF THE INVENTION According to the present invention, since it has excellent electret property and antibacterial property having stable electric charge which is not affected by environmental conditions, humidity and temperature,
Materials suitable for applications such as agricultural materials, wipers, various cover materials, and medical materials can be provided.

Claims (13)

[Claims] 1. A synthetic organic polymer having a volume resistivity of 10 ¹³ Ω · cm or more, wherein the synthetic organic polymer contains a heat stabilizer and an arsenic compound having a phenoxy group, and the surface thereof. An antibacterial electret material having a charge density of 1 × 10 ^-10 coulomb / cm ² or more. 2. The antibacterial electret material according to claim 1, wherein the heat stabilizer is contained in the range of 0.01 to 2% by weight. 3. An arsenic compound having the phenoxy group,
The antibacterial electret material according to claim 1, containing 0.005 to 0.5% by weight. 4. The heat stabilizer is at least one of hindered amine-based, nitrogen-containing hindered phenol-based, metal salt hindered phenol-based, phenol-based, sulfur-based, and phosphorus-based heat stabilizers. 1. The antibacterial electret material according to 1. 5. The arsenic compound having a phenoxy group is 1
0,10'-oxybisphenoxaarsine 10,1
The antibacterial electret material according to claim 1, which is at least one kind of 0'-thiobisphenoxaarsine, 10,10'-oxybisphenalsazine and 10,10'-thiobisphenalsadine. 6. The volume resistivity of the synthetic organic polymer is 10 ¹⁵ Ω.
The antibacterial electret material according to claim 1, which is composed of an olefin polymer having a cm or more. 7. The antibacterial electret material according to claim 6, wherein the olefin polymer mainly comprises polypropylene. 8. The heat stabilizer contains at least two kinds of heat stabilizers of hindered amine type, nitrogen-containing hindered phenol type, metal salt hindered phenol type, phenol type, sulfur type and phosphorus type heat stabilizer, Its total content is 0.01
The antibacterial electret material according to claim 1, which is ˜2% by weight. 9. The antibacterial electret material according to claim 1, wherein the antibacterial electret material is in the form of fibers. 10. The antibacterial electret material according to claim 9, wherein the fiber form is a non-woven fabric. 11. The antibacterial electret material according to claim 10, wherein the nonwoven fabric is a melt blown nonwoven fabric. 12. A filter comprising at least a part of a filter medium made of the antibacterial electret material according to any one of claims 1 to 11. 13. The filter according to claim 12, which is for an air cleaner or a vacuum cleaner.