JPH0317957A - Nickel plated unwoven electrode and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a nickel plated unwoven electrode excellent both in tensile strength and adhesion of its plating by forming a nickel film by means of electroless plating on the surface of a specific base unwoven fabric. CONSTITUTION:An amine hardening epoxy resin 4 is applied as an interfiber bonding agent to a fiber aggregate comprising organic fibers 1, i.e. a fiber web formed by the card method, air lay method or the like. An electroless nickel plate 5 is applied to an unwoven cloth formed by sticking and covering portions 2 to each other where fibers forming the web cross and contact each other, and interfiber surfaces 3. Thus the adhesion strength of the nickel plate 5 attached to the surface of an epoxy resin cover 4 formed on the fiber surface is enhanced and an electrode material excellent in electrode strength and in which porous high capacity is achieved is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nickel-plated porous nonwoven fabric electrode used as an electrode for a nickel-cadmium alkaline battery and a method for manufacturing the same.

[Conventional technology and its problems]

Traditionally, nickel-cadmium alkaline batteries! The electrode is made by sintering a porous nickel plate and Nijikeru powder, but the porosity is only about 80%, making it impossible to increase the capacity of the battery. Therefore, a material with a high porosity is required.

On the other hand, as a method for obtaining an electrode material with a large porosity, as shown in Japanese Patent Publication No. 38-17554, Japanese Patent Publication No. 49112134, Japanese Patent Publication No. 61-40721, Japanese Patent Publication No. 61-76686, organic fibers are used. Or using organic foam as a base material,
(1) Impregnated with nickel powder, sintered and reduced, (
It is classified into 2) those that are fired and reduced after nickel plating, and (3) those that are used as is after nickel plating.

Both (1) and (2) above require heat treatment in a reducing atmosphere, which makes continuous long roll-shaped electrodes impossible to operate continuously during battery assembly, making them difficult to use for special purposes. The problem is that it can only be used. Therefore, from this point of view, it has been considered to coat an organic fiber non-woven fabric made of alkali-resistant fibers with nickel using an electroless plating method to make an electrode material. It has drawbacks such as low strength and the inability to obtain products with satisfactory characteristics.

[Problem to be solved by the invention]

The present invention was developed as a result of intensive research to solve the drawbacks of the conventional nickel electrode plates, namely, the low porosity and the impossibility of continuous use when the porosity is increased. Fiber aggregates that may cause problems, such as card method, air lay method,
An amine-curing epoxy resin is applied as an interfiber binder to a fiber web formed by a spun-pond method, a melt-bubbled method, etc., and the parts where the web structure intersects and contacts each other and the interfiber surfaces are bonded. Electroless nickel plating is applied to the coated nonwoven fabric, which increases the adhesion of the nickel plating to the surface of the epoxy resin coating formed on the surface of the fibers, and provides excellent electrode strength. We have succeeded in obtaining an electrode material that can be operated continuously.

The organic fiber used in the composition of the present invention is preferably alkali-resistant, such as polyolefin, polyvinyl chloride, etc. Polyacrylonitrile type. Use polyamide, etc. Webs as fiber aggregates formed using such fibers can be used in the form of random webs, cross webs, parallel webs, etc., as well as spunbond methods. Melt blow method. A nonwoven fabric formed by the 7 rush spinning method, or a nonwoven fabric formed by a fiber entangling method such as a needle punching method or a water-21 dollar punching method may be used.

In addition, amine-curing epoxy resins that can be applied to the above webs and non-woven fabrics to bond and coat the fibers include bisphenol A type, bisphenol F type, tetrahydride-7enylmethane, polyalcohol type, polyglycol type, Selected from resorcinol type, noporac type, etc.

Further, as the curing agent for the epoxy resin, aliphatic amines, cycloaliphatic amines, and aromatic amines are preferable, such as N-aminoethylbiperazine, metaxylene diamine,
These include paramethanediamine, 44'-diaminodi7enylmethane, and the like.

Next, in the present invention, the purpose of adhering and covering the organic fiber aggregate using epoxy resin is to increase the strength of the nonwoven fabric to be formed and to improve the adhesion of the nickel-plated nonwoven fabric. Other hardening agents, such as phthalic anhydride, if only for increasing the size. Although acid anhydrides such as pyromellitic anhydride may be used, amine-based curing agents are suitable in order to improve the adhesion of nickel plating.

Methods of using epoxy resin as an interfiber binder or coating with epoxy resin include dipping method, foam glue method, and spray method. Any method other than the coating method may be used, but the dipping method is preferable in order to uniformly bond the fibers and uniformly coat the fiber surface.

The electroless nickel plating process consists of a. scouring with surfactants, b. Catalysis with palladium, c. This is done in the order of plating.

b. Catalysis with palladium can be carried out by (l) treating with stannous chloride/hydrochloric acid aqueous solution and then catalyzing with palladium chloride/hydrochloric acid aqueous solution; (2) using palladium chloride/hydrochloric acid aqueous solution using the amino group of the curing agent. Although there are methods of catalyzing the film with only the above method, method (1) has the best adhesion.

As a reducing agent for electroless nickel plating, Iruri hydrazine is used to obtain high purity nickel. hydrazine sulfate,
A hydrazine derivative such as hydrazinium chloride is used.

In addition, the organic fiber nonwoven fabric used for electroless nickel plating can be easily obtained in a continuous length and coated with epoxy resin in a continuous process, and then electroless nickel plating can be performed continuously. Alternatively, the material may be wound into a roll and plated by forcibly circulating the plating solution using a dyeing machine.

The present invention will be explained in detail below with reference to Examples.

〔Example〕

Nylon (4) and polypropylene (8) as organic fibers
, polyvinyl chloride 0, and polyacrylonitrile 0 were used individually, and a cross web with a fiber basis weight of 60 g/i was formed using a web-forming machine, such as a card and a cross wrapper machine.

Next, each of the above-mentioned cross webs was introduced into a dipping tank filled with the following mixed solution, and after dipping, it was mangled. The blended liquid was adjusted to 50 parts (weight ratio of solid content) to 100 parts of fiber using a dehydrator or the like.

Mixed liquid a. 828 type epoxy resin
lOO section (Epolsion EA55: manufactured by Kanebo NSC) b. Polyamide hardener
20 parts (Epokey H258: manufactured by Mitsui Petrochemicals) c. Water However, the blending ratio of A and B indicates the solid ratio, and while keeping the ratio of A and B constant, water is added to make the concentration 20% (solid content).

Next, the web impregnated with the compounded liquid is introduced into a dryer, dried,
After heat treatment, each layer has a thickness of 2.5 mm as shown in Table 1. 5
mm-2. 7 A base nonwoven fabric having trII1 and a basis weight of 90 g was formed.

Table 1 Comparative Example 1 Cross webs A to D made of the same fibers and shaped to the same basis weight as in the example were immersed in the following blended solution.

Mixed liquid a. 828 type epoxy resin 1
00 copies (Adeka Resin EP4 100: manufactured by Asahi Denka Co., Ltd.)
B. acid anhydride
85 copies (ADEKA HARDONA EH700: Asahi Denka Co., Ltd.) c.
However, the blending ratio between A and N indicates the solid ratio.

Keeping the ratio of A and B constant, add xylol to a concentration of 20% (
solid content).

After soaking, mangle the blending liquid to 50 parts per 100 parts of fiber (
The weight ratio of the solid content was adjusted so that the weight ratio of the solid content was adjusted, and the mixture was introduced into a dryer and subjected to drying and heat treatment to form base nonwoven fabrics A to D, respectively.

Comparative Example 2 A cross web A-D made of the same fibers and shaped to the same basis weight as in the example was used and lightly needle-punched to obtain a nonwoven fabric.

Each base material nonwoven fabric obtained in the above Examples and Comparative Example 1.2 (
1m wide x 50m long) is wrapped around the carrier of the dyeing machine, the scouring agent is circulated, washed with water, and then stannous chloride/LOgI
Q. An aqueous solution containing 20 mQ/Q of hydrochloric acid was circulated, and after washing with water, an aqueous solution containing 1 g/Q of palladium chloride and 20 tnQ/Q of hydrochloric acid was circulated for catalysis.

After washing with water, nickel sulfate L8y/Q. Sodium citrate IJ uA 10 gIQ. Hydrated hydrazine 50mα/l2.
An electroless nickel plating solution containing 100 mQ/Q of 25% ammonia water was heated to 80' (!) and circulated.
After a period of time, circulation was stopped, and washing and drying were performed.

As shown in the drawings, the nickel-plated non-woven fabric electrode of the present invention formed in this manner is made of nylon that constitutes the non-woven fabric electrode.
The part where organic fibers such as polypropylene (1) intersect and contact each other (2), and the surface of the fibers extending from this part (3)
is adhered and coated with an epoxy resin (4), and nickel (5) is firmly adhered to the surface of the fiber coated with the epoxy resin (4) by electroless plating to form a continuous coating.

Further, Table 2 shows the results of measuring the characteristic values of the nickel-plated nonwoven fabric electrodes obtained in the above Examples and Comparative Examples.

Table 2 As is clear from Table 2, the porosity and volume resistance of Examples A to D, which are excellent in both plating adhesion and nonwoven fabric tensile strength, were measured.

Incidentally, the porosity is determined by the thickness required to impregnate the active material.
Although it was calculated as 5m+n, it actually has a porosity higher than that.

The measurement results are shown in Table 3.

Table 3 4 A new electrode material not seen before was obtained.

[Brief explanation of drawings]

(1)...Organic fiber (3)...Fiber surface (5)...Nickel coating (2)...Cross contact area (4)...Epoxy resin

Claims (3)

[Claims] (1) A nickel-plated nonwoven fabric electrode characterized by forming a nickel coating by electroless plating on the surface of a base nonwoven fabric made by integrally adhering and coating an organic fiber aggregate using an epoxy resin as a binder. . (2) The nickel-plated nonwoven fabric electrode according to claim 1, wherein the curing agent for the epoxy resin is an aliphatic amine, a cycloaliphatic amine, or an aromatic amine. (3) After forming a nonwoven fabric by bonding and covering the fibers together with an epoxy resin by applying a binder such as impregnating, coating or spraying the organic fiber aggregate, scouring and catalytic activation treatment are performed, A method for producing a nickel-plated nonwoven fabric electrode, comprising forming a nickel film on the surface of an epoxy resin covering the fiber surface of the nonwoven fabric by electroless plating.