JP2521615B2 - Reticulated electret and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a reticulated electret useful as a dust filter.

[0002]

2. Description of the Related Art A dust-removing filter (electret fibrous filter) composed of a non-woven fabric of electrically charged fibers has been proposed (Japanese Patent Publication No. 56-47299).

However, a dust removal filter made of such a non-woven fabric has a large ventilation resistance, a large amount of charge is attenuated by moisture, fibers are easily scattered during use, and the collected dust is removed from the filter by a method such as washing with water. When it is reused, it has the drawbacks that it is difficult to remove dust, the fibers easily fall off, it is not self-supporting, and it is difficult to mount it on the device.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a reticulated electret suitable for use as a dust-removing filter and a method for producing the same, which has a large amount of charge, has a small air flow resistance, and can easily remove and reuse collected dust. The purpose is to

[0005]

The reticulated electret of the present invention is a mesh composed of electrically insulating polymer fibers whose surface is coated with a resin layer selected from the group consisting of silicone resin, fluorine resin and urethane resin. Is electrostatically charged.

Such a net-like electret is obtained, for example, by coating the surface of a net made of electrically insulating polymer fibers with a resin selected from the group consisting of a silicone resin, a fluororesin and a urethane resin, and then carrying out a charging treatment. It can be manufactured.

The mesh used here is composed of electrically insulating polymer fibers. Polymer fibers have a volume resistivity of 10 ¹⁰
Ω · cm or more, preferably 10 ¹² Ω · cm or more is used. Examples of the raw material polymer material for the polymer fiber include polyethylene terephthalate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, and polyamide. The mesh is formed from polymeric fiber monofilaments or twisted yarns. How to knit a net,
The thickness of the constituent fibers is not particularly limited. Dust removal efficiency,
Considering ventilation resistance, in the case of a plain weave net, a net corresponding to 10 to 60 mesh is preferable. Further, a net woven in a honeycomb shape is also suitable. The resin for coating the surface of the net is selected from the group consisting of silicone resin, fluorine resin and urethane resin. The surface of the net is coated with such a resin by forming a layer of a resin-forming composition or emulsion on the surface of the net by a dipping method, a spray method, a coating method, etc., and then drying and curing the layer. be able to.
Amount of resin coating 5 to 50 g / m ² as a basis weight, and preferably from 10 to 30 g / m ^2.

Prior to the resin coating, it is preferable to electrically, chemically or physically treat the surface of the net to improve the adhesiveness with the coating resin. Examples of these treatments include treatment with a Desler coil, acid treatment, and sandblast treatment. It is also effective to apply an undercoat on the surface of the net to improve the adhesion.

Next, the net covered with the resin is charged. The charging treatment can be performed by a known method, but corona discharge treatment is suitable. The corona discharge treatment is performed by placing a net on the flat metal plate electrode and performing corona discharge using the needle electrode as a counter electrode. This corona discharge treatment is preferably performed while heating. The heating is performed at a temperature at which the polymer fibers constituting the net do not soften or deform.

The reticulated electret of the present invention is formed by weaving a resin-coated fiber obtained by coating an electrically insulating polymer fiber with a resin selected from the group consisting of a silicone resin, a fluororesin and a urethane resin into a reticulated state, and then charging it. To be processed
It can also be manufactured by a method of forming a net shape by knitting after being charged.

The reticulated electret of the present invention has an extremely large amount of electrification as compared with a reticulated net not coated with a resin. The reason for this is not clear, but it is considered that in addition to the coating resin layer being easily charged, electric charges are easily trapped at the interface between the polymer fiber and the coating resin layer.

Further, the reticulated electret of the present invention has a small amount of charge reduction due to washing with water and the like, and when used as a dust filter, the collected dust can be removed by washing and reused.

Since the electret of the present invention has a mesh shape, it has a small airflow resistance and can easily remove the collected dust, and is suitable as a dust filter.

[0014]

Function: A net made of electrically insulating polymer fibers which has been subjected to the electrification treatment as it is has a small electrification amount.

However, as in the present invention, the surface of the net made of electrically insulating polymer fibers is coated with a resin selected from the group consisting of silicone resin, fluororesin and urethane, and then subjected to a charging treatment to reduce the charge amount. Very large reticulated electrets can be produced. The details of the reason are unknown and will be awaited for future elucidation, but in addition to the fact that the resin layer coated on the surface easily traps electric charge, the electric charge is easily trapped at the interface between the polymer fiber and the coating resin layer. Presumed.

[0016]

Industrial Applicability The reticulated electret of the present invention is useful as a dust filter because it has a large amount of charge, has a small ventilation resistance, and can easily remove adhering dust.

[0017]

EXAMPLES The present invention will be specifically described with reference to the following examples.

Examples 1-18 and Comparative Examples 1-7.

Silicone resin, tetrafluoroethylene resin and urethane resin were coated on the surface of the mesh composed of the fibers of the polymer substances shown in Tables 1 and 2.

Prior to the resin coating, a conductive plate was used as one electrode and a net was placed on the upper part, and a discharge treatment was performed with a Tesler coil.

The silicone resin coating is a coating silicone (TSE399: Toshiba Silicone Co., Ltd.).
After immersing the net in a solution dissolved in hexane to a concentration of 1.5% by weight, the net was pulled out from the solution, dried at room temperature for 6 hours, and then cured at 60 ° C. for 2 hours.

The tetrafluoroethylene resin coating is a tetrafluoroethylene resin coating material (New TFE coat FC-10
2: Fine Chemical Japan Co., Ltd.) was uniformly sprayed on the surface of the net, dried at room temperature for 6 hours, and then dried at 60 ° C. for 2 hours.

The urethane resin coating was prepared by immersing a net in a solution prepared by dissolving a two-component urethane (Quinnate: Nippon Zeon Co., Ltd.) in toluene to a concentration of 5.0% by weight, then lifting the solution from the solution and drying at room temperature for 6 hours. Then, it was cured at 60 ° C. for 2 hours.

Next, the net thus coated with resin and the net not coated with resin (Comparative Example) were subjected to a charging treatment by corona discharge. The needle electrodes are arranged at 5 mm intervals as anodes, the flat metal electrodes as cathodes, and the net is placed on the cathodes. Temperature 90 ° C, distance between electrodes 13 mm, applied voltage 6K
Corona discharge was performed at V for 3 minutes to perform a charging treatment.

The surface potential of the reticulated electret thus produced was measured. The surface potential is measured by a surface potential meter (model STATIRON TYPE-TH: Shishido Shokai).
This was performed using

Tables 1 and 2 show the properties of the net using the value of the surface potential of the net electret and the type of coating resin.

A commercial detergent (Mama Lemon: Lion Oil & Fat Co., Ltd.) is used in an amount of 0.5% by weight of the reticulated electret.
After ultrasonic cleaning with added tap water for 10 minutes, rinse with running tap water for 20 minutes and drain, then at room temperature for 6 hours,
The surface potential was also measured for the one dried at 60 ° C. for 2 hours. Tables 1 and 2 show the surface potentials measured for the washing operation performed once and twice.

[0028]

[Table 1]

[0029]

[Table 2]

Claims (4)

(57) [Claims] 1. A surface of a silicone resin, a fluorine resin,
A reticulated electret in which a net composed of electrically insulating polymer fibers covered with a resin layer selected from the group consisting of urethane resins is electrostatically charged. 2. The surface of a net made of electrically insulating polymer fibers is coated with a resin selected from the group consisting of silicone resin, fluorine resin and urethane resin, and then charged. Method for manufacturing reticulated electret. 3. The surface of the electrically insulating polymer fiber is coated with a resin selected from the group consisting of silicone resin, fluorine resin, and urethane resin, formed into a net, and then charged. Method for producing reticulated electret. 4. The surface of the electrically insulating polymer fiber is coated with a resin selected from the group consisting of a silicone resin, a fluorine resin, and a urethane resin, and then subjected to a charging treatment to form a net. Method for manufacturing reticulated electret.