JPS5925614B2 - 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, electrostatic filters, etc. 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 (
However, it has the disadvantage of a short lifespan for maintaining effective performance.

In order to overcome these drawbacks of conventional devices, the present invention aims to provide an electret i-filter that utilizes an electret polymer film as a filter and has excellent dust collection performance and a long service life.

The present invention involves continuously bending or folding an electret polymer film, forming pleats on the entire surface of the film to give it thickness and creating a large number of continuous voids, and converting this pleated electret film into a flat electret film. The main material of the electret filter is a laminated product formed by stacking films in the thickness direction and adhering or fusing the tips of the pleats to the film surface.

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, which are unsaturated carboxylic acid resins. and those obtained by blending or raft polymerizing 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 a thickness of about 3μ to 31L and stretched in one or two directions if necessary.

This polymer film may be foamed or porous (or may be cross-linked), or may be a non-woven film (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.

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 a flat electret film 4 interposed therebetween, and flat electret films are attached above and below,
The ends of the pleats are adhered or fused to the electret film 4 to form a pleated electret film laminate 5.

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 strained cylinders are created. Electret films 6 are stacked in the thickness direction with ordinary electret films 9 interposed therebetween, and electret films 9 are attached to the upper and lower sides,
The ends of the pleats are adhered or fused to the electret film to constitute a pleated electret film laminate 10.

Figure 3 shows a specific example of a filter, in which a pleated electret filter laminate 5 is inserted into a box frame 11 with both front and rear sides cut out, and the air to be purified is passed through the box frame 11.
It flows in the front and back direction of 1 and passes through a continuous porosometer.

The present invention is as shown in the first and second embodiments (an electret film is continuously bent or folded to form pleats 2 and 7 on the entire surface of the film, and the pleated electret films 1 and 6 are flattened, respectively). Electret film 4
, 9 in the thickness direction, and the tips of the pleats are adhered or fused to the film surface, and the main materials of the filter are laminates 5 and 10, and the air to be purified is passed through the folds. direction and passes through the continuous gap 3.8.

In the present invention, since the contact area between the air and the electret film is expanded, the dust collection efficiency is improved, and the air can easily circulate, resulting in less pressure loss. Because of this, it does not lose its shape, and because it does not flap during use, the dust that has adhered to it does not scatter, and these factors combine to provide a filter with excellent dust collection performance and a long life.

The filter according to the present invention can be replaced with a conventional nonwoven fabric filter (A
), (B), and (q and filter p laminated with flat electret films) are as shown in Table 1.

As is clear from Table 1, the present invention has zero pressure loss and high efficiency.

On the other hand, among the nonwoven fabric filters, (A) has relatively low pressure loss but low efficiency, while (B) and (Q have good efficiency but high pressure loss).

In addition, the pressure loss of the flat electret film laminate product is 0, and the initial efficiency is relatively good, but the efficiency rapidly decreases with the passage of time. Once attached, dust does not scatter again, and the pressure loss is extremely small, which saves energy.The large contact area allows for a high dust collection rate (both initial efficiency and efficiency over time are excellent, etc.). has.

[Brief explanation of the drawing]

1 and 2 are front views showing the first and second embodiments of the present invention, respectively, and FIG. 3 is a perspective view showing a specific example of the filter. Note that 1 and 6 are pleated electret films, 2 and 7 are pleats, and 3 and 8 are continuous voids.

Claims (1)

[Claims] 1 The electret polymer film is continuously bent or folded to form pleats on the entire surface of the film to increase its thickness and create a large number of continuous voids, and the pleated electret film is then folded through a flat electret film. An electret filter whose main material is a laminated product made by stacking the folds in the thickness direction and gluing or fusing the tips of the pleats to the film surface.