JPS5925612B2 - electret filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electret filter used for removing particulates mixed in gas or liquid for purposes such as air purification, dust collection, and dust removal.

Electric dust eliminators and electrostatic filters are already in use as devices to purify the air by removing cigarette smoke and dust from the air, but these devices not only have high equipment costs but also lack effective performance. The disadvantage is that it has a short service life.

In order to eliminate such drawbacks of conventional devices, the present invention aims to provide an electret filter that has excellent dust collection performance and a long life by utilizing an electret polymer film as a filter.

In the present invention, an electret filter is constructed using a laminated product in which electret polymer films are laminated in the thickness direction with conductive sheets interposed therebetween as the main material.

In addition, the present invention involves continuously bending or folding an electret film, forming pleats on the entire surface of the film to increase its thickness, and creating a large number of continuous voids, and then passing this pleated electret film through a conductive sheet to increase its thickness. The main material of the electret filter is a laminated product in which the folds are stacked in this direction and the tips of the pleats are adhered or fused to a conductive sheet.

The polymeric substance used in the present invention may be any material that can be formed into a film by melt molding, casting, cutting, etc., such as thermoplastic resins such as polyolefin resins, polyester resins, and polyamide resins; Thermosetting resins such as phenol resin, formaldehyde resin, urea-formaldehyde resin, and melamine-formaldehyde resin are used.

Among these, preferred are polyolefin resins such as polyethylene, polypropylene, poly-4=methyl-1-pentene, and polystyrene, which have excellent electret performance, as well as polyester resins such as polyethylene terephthalate and polycarbonate resins. and those obtained by blending or graft polymerization with derivatives thereof.

Furthermore, conventionally known stabilizers such as antioxidants and heat-resistant stabilizers may be added to these resins as necessary.

The polymer film is usually made to have a thickness of about 3 μm to 3 mm, and is stretched in one or two directions as necessary.

This polymer film may be foamed or porous, may be crosslinked, or may be a nonwoven film, and two or more films may be laminated.

The polymer film is made into an electret by various known methods such as a thermal electret method, an electroelectret method, a radio electret method, a mechanoelectret method, a magnet electret method, a photoelectret method, and the like.

This electret processing is performed at the same time as the film forming, or before or after the film forming, depending on the purpose.

As the conductive sheet used in the present invention, aluminum wheel,
These include wire mesh, conductive plastic, metal-deposited plastic, etc.

Next, embodiments of the present invention will be described with reference to the drawings.

In the first embodiment shown in FIG. 1, an electret film 1 is continuously folded into a mountain shape, and folds 2 are formed on the entire surface of the film to increase its thickness, and a large number of continuous gaps 3 of triangular cylinders are created. The attached electret films 1 are stacked in the thickness direction with conductive sheets 4 interposed therebetween, and conductive sheets 4 are attached above and below, and the ends of the pleats are glued or fused to the conductive sheets 4 to interpose the conductive sheets. A laminate 5 of the pleated electret film is constructed.

In the second embodiment shown in FIG. 2, an electret film 6 is folded into a continuous pile shape, and pleats 7 are formed on the entire surface of the film to increase its thickness, and a large number of continuous voids 8 of heavy cylinders are created. Electret films 6 are stacked in the thickness direction with conductive sheets 9 interposed therebetween, and conductive sheets 9 are attached above and below, and partition pieces 9' protruding from each conductive sheet are inserted into the continuous gap 8. The ends of the pleats are adhered or fused to the conductive sheet 9 to form a laminate 10 of pleated electret film.

The third embodiment shown in FIG.
is continuously folded into a vertically elongated trapezoidal shape to form pleats 12 on the entire surface of the film to increase its thickness and to create a large number of prismatic cylindrical continuous voids 13. This pleated electret film 11 is then folded into a conductive sheet 14. The pleated electret film laminate 15 is constructed by stacking the pleated electret films in the thickness direction and adhering or fusing the tips of the pleats to the conductive sheet 14.

In such a laminated product 5 of electret films, the surface potentials of the conductive sheets 4 are set to have opposite polarities as shown in FIG. 4 or to have the same polarity opposite as shown in FIG. 5.

The same applies to the electret laminates 10 and 15 of the second and third embodiments.

Fig. 6 shows a specific example of a filter, in which a laminated product 5 of a pleated electret filter is inserted into a box frame 16 with both front and rear sides cut out, and the air to be purified is passed through the box frame 16.
6 in the front-back direction and pass through a continuous air gap meter.

In the present invention, as shown in the first to third embodiments, an electret film is continuously bent or folded to form pleats 2, 7, and 12 on the entire surface of the film, and the pleated electret films 1, 6, and 11 are The main material of the filter is a laminate product 5.10, 15, which is stacked in the thickness direction and the tips of the pleats are glued or fused to the conductive sheet 4.9.14, and the air to be purified is flows in the direction of the folds and passes through the continuous voids 3, 8.13.

In the present invention, the main material of the filter is a laminated product in which electret films are laminated via conductive sheets, and the dust collection efficiency is remarkable whether the surface potentials of the conductive sheets are opposite polarities or opposite polarities. In particular, in the case of homopolar facing, the structure can be obtained by bending a long film, making it easy to manufacture.

In addition, in the present invention, since the contact area between air and the electret film is expanded, dust collection efficiency is improved, and air can easily circulate, resulting in less pressure loss. Since it is bonded or fused, it does not lose its shape, and since it does not flap during use, the dust that has adhered to it does not scatter, and these combine to provide a filter with excellent dust collection performance and a long lifespan. be.

Table 1 shows a comparison of the filter according to the present invention with a filter that does not have conductivity.

As is clear from Table 1, the presence or absence of a conductive sheet has no relation to pressure loss, but in the present invention, the initial efficiency and aging efficiency are high (the two efficiencies are almost unchanged, so the filter according to the present invention has a high initial efficiency and a high aging efficiency. It can be seen that the lifespan is significantly longer.

According to the present invention, since the main material of the filter is a laminated product of electret film with a conductive sheet interposed therebetween, the dust collection efficiency is extremely high and the service life is extremely long. Since it does not flap during use, the dust that has adhered to it will not be dispersed again, and the pressure loss is extremely small, which saves energy.The contact area is large, so dust collection efficiency is high, and both initial efficiency and efficiency over time are excellent. It has many effects such as:

[Brief explanation of the drawing]

1, 2, and 3 are front views showing the first to third embodiments of the present invention, FIGS. 4 and 5 are explanatory diagrams of the surface potential of the conductive sheet, and FIG. 6 is a specific example of the filter. It is a perspective view showing an example. Note that 1, 6, and 11 are pleated electret films, 2, 7, 1, and 2 are pleats, 3, 8, and 13 are continuous voids, and 4
, 9 and 14 are conductive sheets.

Claims (1)

[Scope of Claims] 1. An electret filter constructed by laminating electretized polymer films in the thickness direction with conductive sheets interposed therebetween to construct a laminate product, and using this laminate product as the main material. 2. Continuously bend or fold the electret film to form pleats on the entire surface of the film to increase its thickness and create a large number of continuous voids, and then fold this pleated electret film in the thickness direction through a conductive sheet. The electret filter according to claim 1, characterized in that it is a laminate product formed by stacking and adhering or fusing the ends of the pleats to a conductive sheet.