JPH01293149A - Dust collection electrode plate for electrostatic precipitator - Google Patents

Abstract

PURPOSE:To prevent thin-walling and peeling of a film due to wear thereof by providing both an undercoat layer of lipophilic conductive coating and a topcoat layer of oil resistant conductive coating with a double-layer structure on a base plate made of electric insulating resin and constituting a dust collection electrode plate. CONSTITUTION:Strong adhesive properties for a base plate 2 made of electric insulating resin are obtained by applying lipophilic conductive coating on the electrode surface 3 of the base plate 2 made of resin and forming an undercoat layer 7. Further a topcoat layer 8 is formed by applying oil resistant conductive coating incorporating resin which shows bonding properties therefor on this undercoat layer 7 and thereby this layer 8 is allowed to act as one kind of protective film or a permeation barrier for the conductive films. Therefore the service life as an electrode plate 1 is remarkably prolonged because nicotine and fine oil droplets are prevented from being infiltrated into the films and stuck thereon and infiltration of a detergent at a time of washing is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Application The present invention relates to a dust collecting electrode plate for an electric dust collector, and more specifically, the present invention relates to a dust collecting electrode plate for an electrostatic precipitator, and more specifically, a dust collecting electrode plate provided inside an air cleaner etc. This invention relates to an electrode plate in which a conductive paint is applied on a resin substrate.

(Prior art and its problems) Conventionally, a thin resin substrate has been used as a dust collection electrode plate installed in an electric precipitator such as an air purifier, from the viewpoint of compacting the dust collection space and improving dust collection efficiency. The dust collecting electrode and the counter electrode were coated with a paint made of a conductive substance such as carbon, and a large number of these electrodes were alternately arranged at minute intervals.

However, electric precipitator air purifiers often use a rental system in which only the filter unit equipped with the dust collecting electrode plate is replaced after several weeks of use. Remove the dust collection electrode plate from the filter unit, wash it to remove dust, etc., and reuse it. Dust collecting electrode plates often have strong adhesion not only to so-called normal dust, but also to cigarette tar and minute oil droplets generated during cooking. Harsh cleaning conditions must be used. Therefore, the electrically conductive material coated on the resin substrate peels off or becomes thinner when washed again, resulting in an economic disadvantage that the life of the dust collecting electrode plate is short.

Therefore, it is an object of the present invention to provide an electrical ##STR2## that eliminates problems such as thinning and peeling due to wear and tear of the conductive material provided on the resin substrate even after severe cleaning and long cycle use/recycling. To provide a collecting electrode plate for a dust machine (Means for solving the problems) According to the present invention, the electrode plate comprises an electrically insulating resin substrate and a coating film of conductive paint provided on the substrate. A dust collection electrode plate for an electric dust collector, wherein the coating film comprises an undercoat layer of a lipophilic conductive paint containing a resin component that has adhesive properties to a resin substrate, and a resin component that has adhesive properties to the undercoat layer. Provided is a dust collecting electrode plate having a multilayer structure with a top coat layer of an oil-resistant conductive paint containing:

(Function) The dust collecting electrode plate of the present invention has a multi-layer structure including an undercoat layer of lipophilic conductive paint and a top coat layer of oil-resistant conductive paint on an electrically insulating resin substrate. It has the following characteristics.

By using the oleophilic conductive paint as the undercoat layer, strong adhesion to the resin substrate can be obtained, and the undercoat layer also contains an oil-resistant resin component that exhibits adhesion to the undercoat layer. By providing a conductive paint as a top coat layer, this top coat layer acts as a kind of protective film or permeation barrier for the conductive paint film, and prevents the aforementioned cigarette tar and fine oil droplets from entering the paint film. It prevents intrusion or strong adhesion, and also prevents detergents, solvents, etc. from entering the coating film or swelling or softening the coating film during cleaning. Thus, according to the present invention, even when the cycle of use as an electrode plate and recycling through washing is repeated many times, thinning of the conductive coating film due to wear and tear and peeling of the coating film are effectively prevented. It becomes possible to significantly extend the lifespan of.

In addition, since both the undercoat layer and the topcoat layer are made of conductive paint, and the adhesion between both layers is extremely good, it is easy to apply a voltage to the entire surface of the electrode, making it possible to charge the electrode. The electrostatic collection and adhesion retention function of dust and other air pollution particles is stably and reliably performed.

(Preferred Embodiment of the Invention) In FIG. 1 showing an example of the electrode plate of the present invention, the electrode plate 1 includes an electrically insulating resin substrate 2 and an electrode surface 3 formed of a conductive paint. and a connecting terminal 4. The electrode surface 3 is formed on the edge of the resin substrate 2, leaving a margin 5. Protrusions 6 are formed at small intervals in this margin portion 5, and these protrusions 6 serve as spacers to form passages at small or minute intervals between each electrode surface. Note that the connection terminal 4 is formed of the same type of conductive coating film that constitutes the electrode surface 3.

In FIG. 2, which shows the cross-sectional structure of the electrode surface 3, the electrode plate of the present invention has an undercoat layer 7 of a lipophilic conductive paint provided on the surface of the electrically insulating resin substrate 2, and an undercoat layer 7 made of a lipophilic conductive paint that is adhered to the undercoat layer. and a top coat layer 8 of an oil-resistant conductive paint containing a resin component having properties.

In FIG. 3 (side cross-sectional opening) showing an example of an electrostatic precipitator using the dust-collecting electrode plate 1 of the present invention, a large-area contaminated air inlet 13 is provided in the front panel portion 12 of the housing 11. A clean air outlet 14 is provided above the front panel portion 12. The panel portion 12 is inserted into the opening/closing cassette 16 via a hinge 15 from the panel side.
A discharge region 35, a dust collection region 19, and a filter member 20 are provided in this order. The discharge region 35 is made up of wires or metal pieces in which a large number of corona discharge electrodes 18 and corona discharge ground electrodes 18a are arranged in pairs at small intervals. The dust collection area 19 consists of a large number of dust collection ground planes 21 and dust collection high-voltage pole surfaces 22 arranged alternately at intervals, and a fine passage 23 between these two pole surfaces. As 21 and 22, a large number of the above-mentioned dust collecting electrodes 1 are arranged at small intervals and used. A high voltage power supply 24 is housed in the front panel part of the housing 11 and a part other than the clean air outlet (the bottom part in the figure), and the corona discharge electrode 18
is connected to the corona discharge high voltage output terminal 25a, the dust collection high voltage pole surface 22 is connected to the dust collection high voltage output terminal 25b, and the dust collection ground plane 2 is connected to the dust collection high voltage output terminal 25b.
1 are respectively connected to the ground terminal 25c. The filter element 20 consists of a granular filler or a porous support.

Inside the housing 11, an intake fan 26 is provided behind the cassette 16 and driven by a motor 27. A partition wall 28 is provided above the cassette 16 and the intake fan 26, and forms an exhaust passage 29 connected to the clean air exhaust port 14.

Contaminant particle-containing air is sucked into the device through the inlet 13 by the fan 26, is generally negatively charged by the discharge region 35, flows into the passage 23 of the dust collection region 19, and passes through the dust collection pole surface 2.
Electrostatic collection of contaminant particles occurs on 1 (dust collection electrode plate 1). Contaminant particles are removed and the purified air is discharged to the outside via the outlet 14.

The resin substrate used for the dust collection electrode plate of the present invention includes polypropylene, polyethylene, 1-butene, l-pentene,
Olefin resins such as 1-hexene can be suitably used,
Among them, polypropylene is particularly suitable. Acrylic resins such as methyl acrylate and methyl methacrylate can also be used, and other resins having similar properties to these can also be used.

This resin substrate is provided with a plurality of protrusions serving as spacers integrally with the resin sheet, and can be suitably produced by press molding, vacuum molding, or the like.

The resin sheet preferably has a thickness of 100 to 500 μm, particularly 200 to 400 μm. If it is thicker than this range, it is disadvantageous in terms of workability and economy during handling such as cleaning, and if it is thinner than the above range, Stationary cleaning is undesirable because it shortens the service life. A polypropylene sheet is particularly suitable from the viewpoint of moldability into an electrode plate shape and durability.

Conductive material The conductive paint used in the present invention has a lipophilic paint in the undercoat layer and an oil-resistant paint in the top coat layer, each containing a conductive substance.

As the conductive substance, conductive carbon is the most suitable and common conductive substance, but it is also possible to mix other metal powders and the like.

The lipophilic paint used in the undercoat layer preferably contains the same type of resin as the resin sheet from the viewpoint of adhesiveness, and from this point of view, olefin resins are preferably used. Furthermore, although not of the same type, acrylic resins can also be suitably used. Suitable lipophilic paints are those containing olefinic resins and acrylic resins. in this case,
The olefin resin component in the coating film is a lipophilic component, which acts to increase the adhesion to the olefin resin substrate.
On the other hand, the acrylic resin acts to enhance the dispersibility of conductive carbon into the paint. As the olefin resin, from the viewpoint of compatibility and dispersibility in paints, low molecular weight polypropylene, maleic anhydride grafted polypropylene,
Acid modified polypropylene such as acrylic acid grafted polypropylene is used. On the other hand, as acrylic resin,
The main constituents are (meth)acrylic acid esters such as ethyl acrylate and methyl methacrylate, and ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride; hydroxyethyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as hydroxypropyl (meth)acrylate; (meth)acrylic acid aminoethyl; (meth)acrylic acid -N-
An acrylic resin containing a polar group-containing monomer of (meth)acrylic acid aminoalkyl esters such as aminoethylaminoethyl is used. The ratio of olefin resin to acrylic resin in lipophilic paint is generally 2:98.
The weight ratio is between 50 and 50.

On the other hand, the above acrylic resin is used as the oil-resistant resin for the top coat.

This acrylic resin has oil resistance because it has the above polar group in the resin molecule, and also contains acrylic resin like the undercoat layer, so it has good adhesion or adhesion with the undercoat layer. Are better. It is not necessary to normally contain an olefin resin in the top coat layer, but it is not necessary to contain an olefin resin in an amount smaller than the olefin resin content of the undercoat layer, for example, less than A, especially less than %. It doesn't make any difference.

The content of the conductive substance per solid content of the paint is 20 to 40
It is preferably in the range 25 to 35% by weight, in particular 25 to 35% by weight. When the amount of conductive material is higher than the above range, the conductive material is likely to peel off due to frequent use and cleaning, and when the amount of conductive material is less than the above range, the electrical resistance of the coating film becomes high, and it may be exposed to polluted air. Dust and dirt will not adhere to the air cleaner, and it will no longer function as an air cleaner.

The electrical resistance of the coating film is generally preferably in the range of 0.1 to 10 Ω.

The undercoat layer preferably has a thickness of 5 to 50 μm, particularly 10 to 30 μm; if it is thicker than the above range, it is economically disadvantageous; if it is less than the above range, the amount of the conductive material applied is reduced. As a result, the dust collection performance becomes inferior as mentioned above.

Also, for the same reason, the top coat layer also has a thickness of 5 to 50 μm.
m, especially! It is preferably within the range of 0 to 30 μm.

As a method for applying these conductive paints to the resin sheet, conventionally known methods such as spray coating and roll coater coating can be employed.

(Example) A dust collection electrode plate for an air cleaner was manufactured under the following conditions.

Example 1 Resin sheet: polypropylene, thickness 350 μm Top coat and undercoat layer Conductive substance = [F] Contains 25% carbon by weight 0 Contains 30% carbon by weight Paint Resin: [F] Acrylic resin paint ■ Modified polypropylene - Acrylic resin paint Resin paint: Polypropylene resin paint Paint thickness: [F] Carbon 15 μm ■ Carbon 20 μm This air cleaner using a filter unit containing 120 dust collecting electrode plates for an air cleaner was used for 30 days.

Thereafter, the dust collecting electrode plate was cleaned according to the following cleaning conditions.

This was repeated 20 times, and the amount of carbon remaining on the dust collecting electrode plate was measured.

1" 1 bean Using a 1% solution of a low foaming detergent with the following composition, heat at 50°C.
After washing with shaking for 2 minutes, rinsing with shaking for 2 minutes, draining and drying.

Nonionic surfactant o, i~5 alkali support 1''; sodium metasilicate 90
~98.9 Chelate Ti 1: EDTA-4Na
1 to 5 According to this, the residual amount of carbon in the top coat layer was 95%.

Comparative Example 1 A dust collecting electrode plate was prepared in the same manner as in Example 1, except that no top coat layer was applied and the overall thickness was the same, and the same tests as in Example 1 were conducted.

According to this, the amount of residual carbon was 20%.

Example 2 Example! For the electrode plate of Comparative Example 1, a durability test was conducted for each of the following items.

1) Dry heating at 90℃, 2) Immersion in 1% H2SO4 (at room temperature), 3) Immersion in 1% NaOH (at room temperature), 4) Immersion in double concentration detergent (50℃), 5) Immersion in triple concentration detergent (at room temperature) ) Soaking, 6) Soaking in oil agent for dust adsorption (at room temperature), 7) Soaking in salad oil (at room temperature), 8) Repeated application and cleaning of salad oil (DDK-1, 0, 2%)
; salad oil 5%) The sample taken was the cleaning solution of Example 1 (50°C).
After washing with shaking (about 60 seconds), shake cedar, running water cedar (
(about 2 minutes).

Each of these samples was subjected to a peel test using cellophane pressure-sensitive tape, and compared with untreated products, the following evaluations were made.

O: No change, △: Peeling aluminum, partial coating surface layer, etc. X: complete peeling, XX = Already peeled off during cleaning.

5. In the repeated salad oil coating and cleaning test, the number of times the coating film withstands is shown.

The results are shown in Table 1.

Table 1 (Effects of the Invention) According to the present invention, by using the lipophilic conductive paint as the undercoat layer, strong adhesion to the resin substrate can be obtained, and an undercoat layer can be formed on the undercoat layer. By providing an oil-resistant conductive paint containing a resin component that exhibits adhesive properties to the coating layer as a top coat layer, this acts as a barrier and remains conductive even after many cycles of use as an electrode plate and recycling through cleaning. This effectively prevents thinning and peeling of the coating film due to wear and tear, making it possible to significantly extend the life of the electrode plate.

In addition, since both the undercoat layer and the topcoat layer are made of conductive paint, and the adhesion between both layers is extremely good, it is easy to apply a voltage to the entire surface of the electrode, making it possible to charge the electrode. Electrostatic collection and adhesion retention of dust and other air pollution particles is performed stably and reliably.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the dust collecting electrode plate of the present invention, Fig. 2 is an enlarged sectional view taken along line II-11 in Fig. 1, and Fig. 3 is an electrostatic precipitator using this dust collecting electrode plate. FIG. 1 is an electrode plate, 2 is a substrate, 3 is an electrode surface, 7 is an undercoat layer, and 8 is a top coat layer. Patent applicant Taiskin Co., Ltd. Figure 3 ZOO,? 4 l'l) Cl/tU procedure 1
1i Seisho (Master) July 25, 1986 Director General of the Patent Office Yoshi 1) Mr. Moon Yi! , Indication of the case 1986 Patent Application No. 119095 2 Name of the invention Dust collection electrode plate for electrostatic precipitator 3 Relationship with the case Person making the amendment Patent applicant Address 1-6-24 Nakatsu, Oyodo-ku, Osaka Name Stock Company Duskin 4, Agent 105 5, No date of amendment order 7, Contents of amendment fl) Specification page 2, line 15, page 12, line 16, 1
On page 3, line 12, "air cleaner" is corrected to "air purifier j." (2) Page 14, lines 6 to 14 are corrected as follows: "This air An air purifier using a filter unit containing 120 dust collection electrode plates for purifiers was used for 28 days.Then, the dust collection electrode plates were cleaned according to the following cleaning conditions.This was repeated 20 times, and the dust collection electrodes The amount of carbon remaining on the plate was measured.
After spray cleaning for 5 minutes, spray rinsing for 4 minutes, draining and drying. (3) On page 15, lines 18 to 19, it is written that [Cleaning (DDK
-1, 0, 2%: salad oil 5%)" should be changed to "Cleaning (nonionic surfactant, 0.2%: salad oil 5%)".
%)”. (4) Correct the first table on page 17 as shown in the attached document 6 No. 1
table

Claims (1)

[Scope of Claims] (1) A dust collecting electrode plate for an electrostatic precipitator comprising an electrically insulating resin substrate and a coating film of conductive paint provided on the substrate, wherein the coating film is adhered to the resin substrate. It has a multi-layer structure of an undercoat layer of a lipophilic conductive paint containing a resin component with adhesive properties, and a top coat layer of an oil-resistant conductive paint containing a resin component with adhesive properties in the undercoat layer. A dust collection electrode plate featuring: (2) The dust collecting electrode plate according to claim 1, wherein the resin substrate is made of an olefin resin sheet. (3) The dust collection electrode plate according to claim 1, wherein the resin substrate is made of a polypropylene resin sheet. (4) A dust collection electrode plate as claimed in the claims, wherein the lipophilic conductive paint and the oil-resistant conductive paint are paints containing carbon as a conductive agent. (5) The dust collecting electrode plate according to claim 4, wherein carbon is contained in an amount of 20 to 40% by weight based on the solid part of the paint. (6) The dust collection electrode plate according to claim 1, wherein the lipophilic conductive paint contains an olefin resin and an acrylic resin, and the oil-resistant conductive paint contains an acrylic resin. (7) The dust collecting electrode plate according to claim 1, wherein the undercoat layer has a thickness of 5 to 50 μm and the top coat layer has a thickness of 5 to 50 μm.