JPH05190292A - Electrode for discharge - Google Patents

Abstract

PURPOSE:To attain generation of a corona discharge at low voltage by forming a discharging electrode out of a conductive fiber sheet consisting of fibers predetermined mean fiber size. CONSTITUTION:A charging electrode is formed of a conductive fiber sheet. In this sheet, a conductive fiber of conduction-worked fiber by metal plating or the like, metal fiber, carbon fiber, metal ion mixing fiber, etc., may be formed in a sheet shape, and a sheet may be formed of a regenerative fiber, semisynthetic fiber, synthetic fiber, inorganic fiber, vegetable fiber, animal fiber and a mineral fiber to perform conduction work of this fiber sheet. A mean diameter of this fiber is 14mum or less preferably 10mum or less. A conductive fiber of coating the fiber surface with electron conjugate polymer is excellent in discharge performance. The fiber sheet may be fabric of plain weave, twill weave, sateen weave, etc., knitted goods, thread lace, net, flat braid, nonwoven, etc., and particularly in the nonwoven fabric, since a vertial fiber can be arranged relating to a charged object, a corona discharge is easily generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge electrode which can be used in an electrostatic precipitator, an electret treatment and the like.

[0002]

2. Description of the Related Art Conventionally, stainless steel, piano wire, tungsten wire, etc. have been used as discharge electrodes for electrostatic precipitators. However, this stainless steel, piano wire, and tungsten wire are wasted in energy because corona discharge does not occur unless a high voltage is applied.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a discharge electrode which causes corona discharge at a low voltage.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a discharge electrode made of a conductive fiber sheet, and a conductive fiber sheet made of fibers having an average fiber diameter of 14 μm or less is more excellent in discharge performance. Furthermore, a conductive fiber sheet having a fiber surface coated with an electron-conjugated polymer is a discharge electrode having more excellent discharge performance.

[0005]

Since the discharge electrode of the present invention is made of a conductive fiber sheet, a plurality of fibers can act on the object to be charged, so that corona discharge occurs even at a low voltage.

The conductive fiber sheet of the present invention may be a sheet of conductive fiber such as metal plated, conductive processed fiber, metal fiber, carbon fiber, metal ion mixed fiber, or recycled fiber, semi-fiber. It may be obtained by forming a fiber sheet from a synthetic fiber, a synthetic fiber, an inorganic fiber, a plant fiber, an animal fiber, a mineral fiber and then conducting the conductive processing of the fiber sheet.

The average fiber diameter of these fibers is 14 μm or less,
If the thickness is more preferably 10 μm or less, corona discharge is more likely to occur, so that it can be suitably used. On the other hand, if the thickness is less than 0.1 μm, the durability is poor. Therefore, the thickness is preferably 0.1 μm or more, more preferably 1 μm or more. As a fiber having this average fiber diameter, by subjecting it to mechanical and / or chemical treatment, fibers that can be divided into ultrafine fibers or fibers that are spun from a nozzle and at the same time a fluid acts to reduce the fiber diameter are generally used. A method of directly producing a fiber sheet by a method called microspun bond can be exemplified, but the method is not limited thereto.

The average fiber diameter of these ultrafine fibers means the length of a straight line which can be taken longest in the fiber cross section. For example, when the fiber cross section is elliptical, it means the long axis, when the fiber cross section is triangular, the length is the longest side, and when it is quadrangular, the diagonal line is longer. Further, the average fiber diameter indicates a value averaged by the abundance ratio of fibers. For example, 70% fiber with a fiber diameter of 20 μm
The average fiber diameter of a fiber sheet in which 30% of fibers having a fiber diameter of 10 μm are mixed is 17 (= 20 × 0.7 + 10 × 0.3) μ
m.

As the fibers that can be divided into the above-mentioned ultrafine fibers, there are sea-island type fibers having a cross section in which one component is arranged with the other component in island form, and multiple bimetal type fibers having a cross section in which different components are alternately laminated. Alternatively, chrysanthemum-shaped fibers having a cross section in which one component is radially arranged in another component can be exemplified.

As the combination of resin components constituting the divisible fiber, polyamide resin and polyester resin, polyamide resin and polyolefin resin, polyester resin and polyolefin resin, polyester resin and polyacrylonitrile resin, Polyamide-based resin and polyacrylonitrile-based resin, polyolefin-based resin and polyacrylonitrile-based resin, and the like can be exemplified, but the invention is not limited thereto.

On the other hand, when the highly crimped fiber is used, the fibrous sheet can be formed in conformity with the shape of the object to be charged, so that any portion of the object to be charged having a complicated shape can be uniformly discharged. it can. Even if a fiber sheet made of highly crimped fiber is molded, the crimp of the highly crimped fiber is only stretched, and the fiber itself is not stretched. The sex does not deteriorate.

The highly crimped fiber may be latent or actualized, but the number of crimps is 15 to 100 fibers / inch in the state where the crimp is actualized, and more preferably. 20 to 90 fibers / inch.

As the highly crimped fibers, there are two types of resins having different shrinkage ratios, a composite fiber having a spiral crimp, or a fiber having a single component and crimping with a specific heat history. Examples thereof include side-by-side type composite fibers composed of high-melting point polyester and low-melting point polyester, which have a large number of crimps and exhibit excellent stretchability, and therefore can be preferably used.

In the case of using already conductive fibers using the above fibers, a fiber sheet is formed to form the discharge electrode of the present invention, and in case of using non-conductive fibers, The discharge electrode of the present invention is obtained by conducting a conductive process after forming the fiber sheet.

The conductive fiber sheet of the present invention includes plain weave, twill weave, satin weave, woven fabrics, knitted fabrics, thread laces, nets,
It may be a flat braid, a non-woven fabric or the like and is not particularly limited, but among them, since the non-woven fabric can arrange fibers perpendicular to the object to be charged, corona discharge is likely to occur and can be suitably used. ..

Among these non-woven fabrics, a non-woven fabric obtained by entanglement of fibers with a web of fibers obtained by a card method, an air-laying method, a wet method, a spunbond method or the like by applying water current or a needle Since the orientation direction of is the thickness direction and there are fibers substantially perpendicular to the object to be charged, corona discharge is more likely to occur.

When the divisible fibers that can obtain the above-mentioned ultrafine fibers are used, the fibers are entangled by water flow or needle punching, and at the same time, the fibers are divided and the fibers are oriented in the thickness direction. Above, it is a preferable method for forming an entangled nonwoven fabric.

When non-conductive fibers are used among the fiber sheets obtained as described above, the fiber sheet is subjected to conductive processing to obtain the discharge electrode of the present invention.

Metal plating treatment as the conductive processing of the present invention,
Examples thereof include vapor deposition treatment, sputtering treatment, ion plating treatment, metal spraying treatment, and coating treatment with an electron conjugated polymer, but are not limited thereto. In addition, the coating treatment with the electron-conjugated polymer has excellent discharge properties, and thus can be preferably used. In addition, it is needless to say that the conductive processing can be applied to the fiber sheet, and the fiber sheet may be formed after the conductive fiber is obtained by performing the conductive processing in advance.

As a method for imparting electrical conductivity to the fiber surface with this electron-conjugated polymer, a solution containing an oxidizing agent such as iron (III) chloride or copper (II) chloride is impregnated into the fiber sheet and then contacted with the monomer. Although the method of polymerizing by doing so can be illustrated, it is not limited to this. Further, the method of contacting with the monomer is to impregnate, coat or spray the fiber sheet to which the oxidant is attached when the monomer is in a liquid state, and when the monomer is in a gas state, it is filled with the monomer. The fiber sheet to which the oxidant is attached may be placed in the container.

Examples of the monomer to be polymerized include acetylene, benzene, aniline, phenylacetylene, pyrrole, furan, thiophene, indole and derivatives of these monomers. Among these, pyrrole is excellent in conductivity and polymerizability and can be particularly preferably used.

The discharge electrode obtained as described above is
For example, it can be used for an electric dust collector, an electret treatment, or an OA device such as a copying machine. When used, it is used in the form of sheet, roll or thread.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0024]

【Example】

Example 1 Polyester fiber (average fiber diameter 3.2 μm,
A fiber web of 100% (fiber length 5 mm) was formed by a wet method and then entangled with a water flow of water pressure of 50 to 95 kg / cm ² to obtain a nonwoven fabric having a basis weight of 100 g / m ² and a thickness of 0.6 mm.

Thereafter, the non-woven fabric was mixed with iron chloride (II
After impregnation with I), the pyrrole solution was brought into contact with the evaporated pyrrole monomer gas to obtain a discharge electrode in which substantially the entire nonwoven fabric was covered with polypyrrole.

(Example 2) A basis weight 20 made of 6 nylon having an average fiber diameter of 2.5 μm was measured by the micro spun bond method.
A non-woven fabric with g / m ² and a thickness of 0.1 mm was obtained. The average fiber diameter is a value calculated by averaging 10 points based on an electron micrograph. Then, this non-woven fabric was processed in exactly the same manner as in Example 1 to obtain a discharge electrode in which substantially the entire non-woven fabric was coated with polypyrrole.

Example 3 A polyester component was used as a main component, and the polyester component was separated into eight sections by a polyamide component and bonded, and a fineness of 2 denier, a fiber length of 38 mm, and 100% chrysanthemum-shaped fiber in cross section were carded. Fiber web, and then entangled with a water flow having a water pressure of 50 to 95 kg / cm ² to obtain a nonwoven fabric having a basis weight of 85 g / m ² and a thickness of 0.45 mm. The average fiber diameter of this nonwoven fabric was 6.1 μm. The average fiber diameter was calculated based on an electron micrograph, the polyester component had an average of 6 μm, and the polyamide component had an average of 7 μm. Then, this non-woven fabric was treated in exactly the same manner as in Example 1 to obtain a discharge electrode in which substantially the entire non-woven fabric was coated with polypyrrole.

(Example 4) Nomex fiber (registered trademark, manufactured by DuPont, average fiber diameter 12.1 μm, fiber length 38)
mm) After carding 100% into a fiber web,
Entangled with a water flow of 50-95 kg / cm ² of water pressure to give a weight of 80 g /
A non-woven fabric with m ² and a thickness of 0.8 mm was obtained. Then, this non-woven fabric was treated in exactly the same manner as in Example 1 to obtain a discharge electrode in which substantially the entire non-woven fabric was coated with polypyrrole.

Example 5 Polypropylene fiber (average fiber diameter 15.4 μm, fiber length 38 mm) 100% was carded into a fiber web, which was then entangled with a water flow of water pressure of 50 to 95 kg / cm ^{2 to} give a basis weight. A non-woven fabric of 50 g / m ² and a thickness of 0.6 mm was obtained. Then, this non-woven fabric was treated in exactly the same manner as in Example 1 to obtain a discharge electrode in which substantially the entire non-woven fabric was coated with polypyrrole.

(Example 6) A non-woven fabric obtained in exactly the same manner as in Example 3 was subjected to a conventional electroless plating treatment to obtain a discharge electrode having 50% nickel adhering to the weight of the non-woven fabric. ..

(Discharge Characteristic Test) As a method for evaluating the discharge characteristic, an electrostatic measuring device (manufactured by Nippon Static Co., Ltd., SV-
7) was used to measure the charged voltage. As the discharge electrode of this device, an electrode cut into 20 × 200 mm in Examples 1 to 6 and a tungsten wire electrode having a diameter of 80 μm as a comparison were moved at 1.5 m / min, and a polyester film having a thickness of 50 μm was used. The electrostatic charges of the polyester film were measured after being placed 0.5 mm apart and applying 1.5 KV. In addition, this measurement was performed under conditions of a temperature of 25 ° C. and a humidity of 30%. The results are shown in Table 1.

[0032]

[Table 1]

From these results, it can be seen that the discharge electrode of the present invention has a large electrification voltage even at the same applied voltage, and therefore discharge occurs even at a lower voltage.

[0034]

The discharge electrode of the present invention is composed of a conductive fiber sheet, and a plurality of fibers can act on an object to be charged, so that corona discharge occurs even at a low voltage.

A conductive fiber sheet made of fibers having an average fiber diameter of 14 μm or less is more likely to cause corona discharge and can efficiently charge an object to be charged.

A conductive fiber sheet whose fiber surface is coated with an electron-conjugated polymer can be discharged more efficiently.

Claims (3)

[Claims] 1. An electrode for discharge, comprising a conductive fiber sheet. 2. The discharge electrode according to claim 1, which is a conductive fiber sheet made of fibers having an average fiber diameter of 14 μm or less. 3. The discharge electrode according to claim 1, which is a conductive fiber sheet having a fiber surface coated with an electron-conjugated polymer.