JPH0560512U - Electret filter media - Google Patents

Abstract

(57) [Summary] [Purpose] The supporting non-woven fabric to be joined to the electretized non-woven fabric has a coarse mesh and has a required waist strength by resin processing so that the electretized effect is not impaired.
Suppress increase in pressure loss. [Structure] An electretized nonwoven fabric 2 and a resin-processed coarse supporting nonwoven fabric 3 are superposed on each other with a sheet 4 for fusion interposed and heat-fused through a heating roll. Since the processing of the resin makes the support stronger, the supporting non-woven fabric may have coarse meshes, which makes the air flow uniform and reduces the increase in pressure loss.
Also, since it is a thin leaf, the folds are sharpened to form a fold-fold filter with a fine pitch.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electret filter medium for capturing dust and other fine particles in the air.

[0002]

[Prior Art]

 Conventionally, a non-woven fabric is known as an electret to electrostatically capture dust, exhaust gas particles, pollen and other fine particles floating in the air. For example, those disclosed in JP-A-60-168510 or JP-A-61-95416. These electretized non-woven fabrics make it easy to electrostatically adsorb dust and the like and to reduce pressure loss with respect to the flow of air. It is composed of non-woven fabric of high density. Therefore, the sheet becomes a very flexible sheet, and for example, in the case of a pleated filter body for an air filter, the electretized non-woven fabric alone cannot maintain its own form and has low strength. Therefore, as the electret filter medium for forming the filter body, an ordinary non-woven fabric is piled up for shape support.

[0003]

[Problems to be solved by the device]

 As described above, in order to maintain the pleated shape of the electretized nonwoven fabric, the supporting nonwoven fabric has finer mesh and higher density than the electretized nonwoven fabric.

The electret filter medium is used such that the upstream side of the air flow is an electretized nonwoven fabric and the downstream side is a supporting nonwoven fabric. However, in the conventional ones as described above, the texture of the nonwoven fabric is deteriorated and the air flow is poor. The air flow passing through the electret non-woven fabric on the upstream side becomes uniform, and the distribution of the air flow becomes non-uniform, and the efficiency of capturing dust and the like decreases.

Further, when the pressure loss of the entire electret filter medium is increased, and when a filter body folded and folded is formed, the pleated portion is rounded due to the thickness of the nonwoven fabric for support, and the pleated pitch becomes rough, or the filtering surface is roughened. There is a possibility that the effective filtration area will be reduced due to the contact with.

[0006]

[Means for Solving the Problems]

 The electret filter medium has a structure in which an electretized non-woven fabric and a supporting non-woven fabric having a coarser mesh than that are superposed and joined.

[0007]

[Action]

 Since the resin-processed non-woven fabric increases in strength and decreases in flexibility and rigidity, it is possible to sufficiently maintain the pleated shape even when it has a coarse mesh when formed into a filter body. Moreover, since it can be made sufficiently thin, sharp folds can be formed and the pleated pitch can be made fine.

[0008]

【Example】

 FIG. 1 shows an example of the electret filter medium of the present invention. The electret filter medium 1 is formed by joining the electretized non-woven fabric 2 and the supporting non-woven fabric 3 with the sheet 4 for fusing interposed therebetween and heat-sealing them with a heating roll (not shown).

The electretized non-woven fabric 2 is a non-woven fabric made of polypropylene fiber having a denier of 3 to 4 and having a basis weight of about 100 gr / m ² , and subjected to a known electret treatment.

The supporting non-woven fabric 3 is made by molding rayon fibers of about 15 denier into a non-woven fabric having a basis weight of about 70 gr / m ² and resin-processed (impregnated) with an acrylic resin 5 having a weight of about 35%. By making the fibers thicker than the electretized non-woven fabric 2 and reducing the basis weight before resin processing as in this example, the supporting non-woven fabric becomes coarser than the electretized non-woven fabric, and the folded shape can be maintained by the resin processing. Stiffness is given and strength is also improved.

The fusing sheet 4 is made of a polyamide fiber of about 5 denier into a mesh sheet having a basis weight of about 10 gr / m ² , and has a melting point of about 90 ° C.

The electret filter medium 1 is formed by stacking the electretized non-woven fabric 2, the fusing sheet 4, and the supporting non-woven fabric 3 and passing them through a heating roll to heat-bond the above three layers. It is not preferable to perform resin processing after heat-sealing the above three layers, because the effect of electretization is diminished.

The electret filter medium 1 is used as a filter element 10 as shown in FIG. The electret filter medium 1 is pleated to form a filter body 11, which is attached and fixed inside a rectangular frame-shaped end plate 12. On the outer periphery of the frame-shaped end plate 12, an elastic synthetic resin packing 13 such as one made porous by foaming is attached to form the filter element 10.

The filter element 10 is attached to a rectangular mounting frame (not shown) to form an air filter, and air is introduced from the side of the electretized nonwoven fabric 2 to remove dust, exhaust gas fine particles, pollen and the like.

The air filter has a prismatic shape and an appropriate shape. For example, the air filter is attached to an outside air intake of a vehicle air conditioner and is used for other indoor air purifiers.

[0016]

[Effect of the device]

 Since the electret filter medium of this invention makes the supporting non-woven fabric coarser than the electretized non-woven fabric to prevent the air flow from becoming uneven, the supporting non-woven fabric inhibits the action of the electretized non-woven fabric to adsorb dust and the like. In addition, the efficiency of capturing dust etc. is improved compared to the conventional one, and the pressure loss is also small.

Furthermore, since the supporting non-woven fabric is processed with a resin, even a thin and coarse one can be stiff and maintain its shape. Therefore, when the filter body is formed into a pleated fold, the folds can be sharpened, and the folds can be formed within the same volume. There is an effect that a wide filtration area can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment.

FIG. 2 is a perspective view of a filter element using the filter medium of the embodiment.

[Explanation of symbols]

 2 Electretized non-woven fabric 3 Supporting non-woven fabric 5 Resin

Claims (1)

[Scope of utility model registration request] 1. An electret filter medium comprising an electretized non-woven fabric and a supporting non-woven fabric having a coarser mesh and made of resin, which are superposed and joined to each other.