JP2000117022A - Filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a honeycomb shaped filter excellent in dust collecting property without increasing thickness and also low in pressure loss and excellent in durability of capturing performance. SOLUTION: A structure 11 is obtained by cutting a structure having a honeycomb shaped cell obtained by forming an electret thermoplastic resin made sheet in a form like honeycomb, at angle θ to vertical line and the structure is disposed so that a cut area may be vertical to a flow line (g) of air and to incline the cell at angle θ to the fluid of the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an air conditioner,
The present invention relates to a honeycomb filter used for an air purifier, an automobile, and the like.

[0002]

2. Description of the Related Art As filters used in air conditioners, air purifiers, automobiles and the like, there are known filters formed by forming electret sheets into a honeycomb shape. That is, Japanese Patent Publication No. 59-25614 discloses a filter in which an electretized polymer film is continuously bent or folded and stacked via a flat electretized polymer film. No. 213945 discloses a filter in which an electret nonwoven fabric is formed into a honeycomb shape.

[0003]

Since the honeycomb filter collects dust on the surface of the sheet forming the honeycomb that contacts the fluid, it is necessary to increase the area in contact with air in order to improve the dust collection. However, there was a problem that the thickness of the filter had to be increased. An object of the present invention is to provide a honeycomb-shaped filter which is excellent in dust collecting property without increasing the thickness, has low pressure loss, and is excellent in persistence of collecting performance.

[0004]

According to a first aspect of the present invention, there is provided a filter in which an electretized thermoplastic resin sheet is formed into a honeycomb shape to form a honeycomb-shaped cell, wherein the cell is formed into a streamline of air flowing into the filter. It is characterized in that it is inclined at an angle to it.

According to the present invention, the area of contact with air is increased by inclining the cell with respect to the streamline of air flowing into the filter. In the present invention, as the thermoplastic resin, various thermoplastic resins can be used, but polyethylene, polypropylene, and poly-4-polyethylene are particularly easy to be electretized and have excellent charge durability.
In addition to polyolefin resins such as methyl-1-pentene and polyester, polyester resins such as polyolefin terephthalate and polycarbonate resins are suitable, and these include those obtained by blending or graft-polymerizing unsaturated carboxylic acids and derivatives thereof. Conventionally known stabilizers such as an antioxidant and a heat-resistant stabilizer are added to these resins as required.

The average surface charge density of the sheet made of electretized thermoplastic resin constituting the filter is usually 0.1 × 10 ⁻⁹ coulomb / cm 2, since it can exhibit sufficient dust collection performance as an electret. cm ² or more, preferably 0.3 to 5 × 10 ⁻⁹ coulomb / cm ² . The thickness of the sheet is 10 μm to 3 mm, preferably 30 μm to 1 mm.

The sheet may be a polymer film formed by a conventionally known melt molding method, for example, a polymer film formed by a cast molding machine, a nonwoven fabric formed by a card method or a melt blown method, or a wet film method. A formed paper-like sheet may be used. These sheets may be stretched in one direction or two directions, foamed, or porous as necessary, or may be crosslinked.

[0008] The electretized sheet of the present invention can be obtained by subjecting the sheet obtained as described above to various conventionally known methods,
For example, it is electretized by a method such as a thermal electret method, an electroelectret method, a radio electret method, a magne electret method, or a mechano-electret method. In the case of a nonwoven fabric or the like, the material may be electretized by molding using a material that has been electretized in advance.

Sheets made of these electret thermoplastic resins are used in a single layer or in a laminate.
One honeycomb-shaped filter may be formed by the same type of forming method and may be used to form a honeycomb-shaped filter using only electretized sheets, or at least two types of electretized sheets formed by different manufacturing methods. The honeycomb filter may be formed by using the above.

The method for molding the sheet made of electretized thermoplastic resin into a honeycomb shape is not particularly limited. For example, after the sheet is slit to a fixed width,
A method of forming a structure having a large number of continuous voids, that is, honeycomb cells, while continuously folding or folding the sheet to form a fold over the entire surface of the sheet so as to have a thickness.

FIGS. 1a to 1c show an example of such a case. An electretized thermoplastic resin sheet 1 is continuously bent in a zigzag shape, and a large number of peaks 2 and valleys 3 are continuously formed. A first sheet 4 is formed (FIG. 1a). Next, the first sheet 4 is overlaid on a flat second sheet 5 made of an electretized thermoplastic resin sheet, and the valley 3
Is bonded to the second sheet 5 to form the structural unit 7 (FIG. 1b). After the required number of such structural units 7 have been created, the second structural unit 7b is superimposed on the first structural unit 7a, and the top 8 of the peak 2 of the first structural unit 7a is attached to the back surface of the second structural unit 7b. Glue to Similarly, the second structural unit 7b
This is obtained by stacking the third structural unit 7c on top and bonding the top 8 of the peak 2 of the second structural unit 7b to the third structural unit 7c, and repeating this stacking and bonding process (FIG. 1c). ), First structural unit 7a and second structural unit 7b
May be formed in a large number, and a plurality of the combinations may be stacked to form a structure having a large number of honeycomb cells 9.

The filter in which the honeycomb-shaped cells are inclined at an angle to the streamline of the air flowing into the filter has, for example, a structure having the honeycomb-shaped cells 9 obtained by the above method as shown in FIG. The body 10 is cut at an angle θ with respect to the vertical line as shown in FIG. 3, and the resulting structure 11 having a thickness e is cut so that the cut surface f is perpendicular to the stream line g of the inflowing air as shown in FIG. Obtained by placing.

The obtained structure 11 has a normal thickness t (= e).
(cos θ) is 3 to 20 mm, and the unit of the honeycomb-shaped cell has a cell height of 0.5 to 6 mm and a bottom of the cell of 1 to 10 mm. The angle θ is 5 to 80 °. The filter composed of the structures 11 obtained as described above may be used alone, or a plurality of structures 11 having different angles θ may be arranged side by side on the same plane as shown in FIG. ,
As shown in FIG. 6, the cut surfaces may be overlapped so as to be in contact with each other, or both may be used in combination.

When a plurality of structures having different angles θ are stacked,
The direction of the flow of the air flowing into the filter is changed to cause turbulence, whereby the contact with the filter is increased and the dust removing effect is improved. The invention according to claim 2 is a structure in which an electretized thermoplastic resin sheet is formed into a honeycomb shape to form a honeycomb-shaped cell inclined at an angle to a streamline of air flowing into the filter. The present invention is characterized in that a plurality of structural bands are formed by superposing another structural band on a body, and the angles of cells of adjacent structural bodies are different.

The structures in the present invention are usually stacked so that the cut surfaces are in contact with each other so that the structures can be easily stacked. However, the cut surfaces may be slightly separated from each other.

[0016]

EXAMPLES Example 1 Polypropylene (Grand Polymer B101 [trade name], manufactured by Grand Polymer Co., Ltd., MFR: 0.5 g / 1)
(0 min), 9000 g of polycarbonate, 500 g of polycarbonate (manufactured by General Electric, Lexan 101 [trade name]) and 500 g of maleic anhydride-modified polypropylene (maleic anhydride graft-modified amount: 3% by weight) were mixed to prepare a resin composition. The obtained resin composition was supplied to an inflation film forming machine (manufactured by Toshiba Machine Co., Ltd.) and
At 0 ° C., a 30 μm thick film was formed. Next, the film was stretched in the longitudinal direction at a stretch ratio of 6.6 times with a hot plate heated to 135 ° C. to obtain a stretched film. Thereafter, the stretched film was applied with an applied voltage of -9 kV (DC),
Electrode gap: After supplying a corona discharge of 8 mm with a residence time of 0.5 seconds and performing charging treatment, the fiber is wrapped on a needle-shaped roll and defibrated in a mesh form, and the obtained electret defibrated yarn is wound around a paper tube. I took it. Next, the electretized defibrated yarn was cut into 90 mm with a cutter, and opened by a cotton opening machine to obtain electretized raw cotton. Then, this electret raw cotton to form the web by supplying the web-forming machine, and supplied to the heat embossing roll set at 130 ° C. bonding the fibers, basis weight: 30 g / m ^2, thickness 0 .21 mm electret nonwoven fabric was obtained. Next, this non-woven fabric was subjected to the structural unit 7 in accordance with the steps shown in FIGS.
Were stacked in 18 stages to produce a honeycomb-shaped electret filter structure having 70 honeycomb cells in one stage having a base of 4.2 mm and a height of 2.7 mm. Then, as shown in FIG. 3, the structure is cut at an angle θ of 15 °,
A test filter having a width of 295 mm, a width of 295 mm and a thickness of 5 mm was prepared.

The collection efficiency of the test filter was measured according to the following method. The measurement results were shown as an average of five measurement values for each time. The results are shown in Table 1 below. Here, the measurement of the collection efficiency, the pressure loss, and the life of the filter were performed as follows. Measurement of Collection Efficiency FIG. 7 schematically shows an apparatus for measuring the collection efficiency. The measurement of the collection efficiency was performed as follows.

First, NaC1 particles (particle size: 0.3 μm) from an aerosol generator (manufactured by Nippon Kagaku Kogyo Co., Ltd.) 15
Was supplied into a chamber 17 into which clean air was introduced through an air filter 16. Na in the chamber 17
After the concentration of C1 becomes constant (2 to 6 × 10 ⁻⁶ / cm ² ), it is sucked by a suction device 18 through a filter sample 19 arranged at the bottom of the chamber 17 in the direction of the arrow, and the wind speed passing through the filter At a constant speed (V = 10 cm / sec), the accuracy of NaCl particles C _in and C _out on the upstream 20 and downstream 21 sides of the filter sample 19 were measured by a verticle counter (KC-01B, manufactured by Rion Co., Ltd.) ]) Measurement was performed by 22a and 22b, and the collection efficiency was determined by the following equation. In the figure, 23 is a flow meter, and 24 is a flow control valve.

Collection efficiency E = (1−C _out / C _in ) × 100 “%” Measurement of pressure loss Differential pressure gauge (KD146 [trade name], manufactured by Yamatake Honeywell Co.)
The pressure loss was measured simultaneously with the measurement of the collection efficiency. Measurement of Filter Life As shown in FIG. 8, a device in which a commercially available air conditioner (manufactured by Matsushita Electric Industrial Co., Ltd., Aeolia [trade name]) 27 and a stirring fan 28 are installed inside an acrylic resin box 26 having a volume ratio of 1 m ^3. Was prepared. Next, the test filter is set in an air conditioner, and after the smoke generated when burning tobacco is injected into the box 26, the attenuation of the smoke density in the box 26 is measured with a dust meter (P- 5 [trade name]).

First, in a state where the filter is not set in the air conditioner, after the smoke generated when one cigarette is burned is injected into the box 26, the air conditioner 27 is operated to reduce the concentration to half the initial concentration. The period is determined and used as the blank value.
A predetermined number of cigarettes are burned, the generated smoke is collected by a filter, and the cumulative number of cigarettes when the half time of the amount of dust in the box reaches half the difference between the blank value and the initial value is filtered. Of life.

Example 2 A density of 0.91 g / cm ² and an MFR of 800 g / 10 min (A
STM D 1238) polypropylene (A) 9
7 parts by weight and maleic anhydride-modified polypropylene (B)
(A graft amount of maleic anhydride: 2.7% by weight, intrinsic viscosity: 0.3 dl / g) and 3 parts by weight were mixed with a tumbler blender to prepare a polyolefin composition (composition I). The content of maleic anhydride in this composition I is:
It was 3.9 × 10 ^-2 mol%.

Next, the composition I was mixed with a screw having a screw diameter of 65.
It was put into a simple extruder of mmφ, melted at 310 ° C., and melted at 20 kg / m from a melt blow die connected to the tip of the extruder.
The material was extruded at the discharge rate at the time and was taken at a take-up speed of 13 m / min to form a melt blown nonwoven fabric. The thickness of the obtained melt blown nonwoven fabric is 0.29 mm, the basis weight is 20 g / m ² ,
The bulk density was 0.075 g / cm ³ and the average fiber diameter was 3 μm. Next, this melt blown nonwoven fabric is continuously applied at a speed of 20 m / min while applying a DC voltage of -18 kv to a charge application device having needle electrodes arranged in two rows at intervals of 5 mm in the length direction. To produce an electret meltblown nonwoven fabric.

Next, in the same manner as in Example 1, polypropylene (Grand Polymer B1
01 (trade name), MFR: 0.5 g / 10 min) 9000
g, polycarbonate (manufactured by General Electric, Lexan 101 [trade name]), 500 g, and maleic anhydride-modified polypropylene (maleic anhydride graft-modified amount:
3% by weight) and a resin composition obtained by mixing 500 g.
It is supplied to a cast film forming machine and has a thickness of 30 at 220 ° C.
It was formed into a μm film. Next, this film was supplied to a corona discharge with an applied voltage of -8 kv (direct current) and an electrode interval of 8 mm for a residence time of 0.5 seconds to perform a charging treatment to obtain an electretized film. This film and the melt blown nonwoven fabric are subjected to ultrasonic treatment (treatment conditions: horn pressure 2.
6 kg / cm ² , frequency 20 kH ₂ , processing speed 14 m / min) to obtain an electret laminated sheet having a basis weight of 47 g / m ² and a thickness of 0.31 mm. Then, using this sheet, as in Example 1, the angle θ was 30 °, the length was 43 mm, and the width was 295.
A test filter having a thickness of 5 mm and a thickness of 5 mm was prepared, and the initial performance and tobacco life of the filter were measured in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 1 Using the same material as in Example 1, a honeycomb-shaped electret structure was manufactured by the same method. This structure was cut at an angle θ of 0 ° in the same manner as in Example 1 to obtain a structure having a length of 70 mm and a width of 297.
A test filter having a thickness of 5 mm and a thickness of 5 mm was prepared. Then, the initial performance and the tobacco life of the filter were measured in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 2 Using the same material as in Example 2, a honeycomb-shaped electret structure was manufactured by the same method. This structure was cut at an angle θ of 0 ° in the same manner as in Example 1, and the length was 43 mm and the width was 295.
A test filter having a thickness of 5 mm and a thickness of 5 mm was prepared. The initial performance and tobacco life of the filter were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[0026]

[Table 1] As can be seen from the above Table 1, the pressure loss of Example 2 was almost the same as that of Comparative Example 2 as compared with Comparative Example 1, but the collection efficiency and service life were improved.

[0027]

According to the first aspect of the present invention, since the honeycomb cells are inclined with respect to the axis of the air flowing into the filter, the contact area with the air can be increased without changing the thickness of the filter. In addition, the collection efficiency and life can be improved without increasing the pressure loss.

According to the second aspect of the present invention, the air flowing into the filter becomes turbulent and the contact with the filter increases, so that the trapping effect is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a process order of a structure having a honeycomb-shaped cell.

FIG. 2 is a perspective view of the structure.

FIG. 3 is a side view showing an example in which the structure shown in FIG. 2 is cut obliquely.

FIG. 4 is a side view showing an example of use of the obtained structure.

FIG. 5 is a diagram showing an embodiment in which structures having different cell angles are combined.

FIG. 6 is a diagram showing another embodiment in which structures having different cell angles are combined.

FIG. 7 is a schematic diagram of a collection efficiency measuring device.

FIG. 8 is a schematic diagram of a life measuring device.

[Explanation of symbols]

 1, sheet 2, peak 3, valley 4, first sheet 5, second sheet 6, bottom 7, 7a, 7b, 7c, structural unit 8, top 9, honeycomb Cell 10, 11 Structure 15 Aerosol generator 16 Air filter 17 Chamber 18 Suction device 19 Filter sample 23 Flow meter 24 Flow control valve 26 Box 27・ Air conditioner 28 ・ ・ Stirring fan

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D019 AA01 BA13 BA20 BB03 BB10 BC01 BC20 BD10 CA01 4D058 JA33 JA39 JB14 JB23 JB25 JB39 JB41 KA23 KA25 KA29 KB05 KB12 SA20 TA02 UA25

Claims (2)

[Claims] 1. A filter in which an electretized thermoplastic resin sheet is formed into a honeycomb shape to form a honeycomb-shaped cell, wherein the cell is inclined at an angle to a streamline of air flowing into the filter. A filter characterized by the following. 2. A structure in which an electretized thermoplastic resin sheet is formed into a honeycomb shape to form a honeycomb-shaped cell inclined at an angle to a streamline of air flowing into a filter. A filter characterized by comprising a plurality of structural bodies in which the structural bands are overlapped, and having different angles of cells of adjacent structural bodies.