JPS5844760B2 - Manufacturing method of perforated metal foil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing perforated elongated metal foils.

Long thin metal foils with repeating patterns of through-holes are in great commercial demand in many fields, including the optical industry, the electronic industry, and the battery manufacturing industry.

These needs have traditionally been met by continuously manufacturing perforated foils by electrodepositing the foils on perforated mandrels.

The above method was proposed by J. van der Waals at a symposium on nickel precipitation in the engineering industry held in October 1963.
``Electrical Formation of Nickel Screens,'' written by A.I.S., and an abstract thereof is published in Nickel Bul 1-etin, IO, 1963.
, pages 235-236.

Although this method is convenient, it is not economical because the life of the mandrel is relatively short, the mandrel is expensive, and it is also expensive to regenerate a mandrel that has deteriorated mechanically and/or chemically during use. isn't it.

Anodic etching techniques are described, for example, in British Patent No. 59178.
As seen in No. 8, it is used for metal molded bodies, and in British Patent No. 1009518, a metal foil is sandwiched between two masks of a desired shape and anodically etched. It is perforated in the formula.

However, this method aligns the two masks and
Problems in accommodating each other make them unsuitable for continuous production of perforated foils.

The invention is based on the finding that perforated metal foils can be produced very economically by an anodic melting method, which allows for the production of perforations with a regular pattern of any size. can be obtained easily.

According to the method of manufacturing a perforated long metal foil according to the present invention, one side of the long metal foil is brought into contact with an endless surface that is inert to an electrolytic solution, and the other side of the metal foil is brought into contact with an endless surface that is inert to an electrolyte. etching through the perforated mask by passing it through an electrolytic etching bath in contact with a perforated endless titanium mask and applying a potential difference of less than IOV between the cathode and the metal foil immersed in the bath liquid. The process consists of anodic etching of the metal foil exposed to the bath liquid.

Although other materials can be used for the mask, it has been found that only titanium is corrosion resistant under anodic conditions and provides the necessary dimensional stability.

This titanium mask can be easily perforated in a desired large pattern by conventional means.

The endless surface can be the surface of an endless belt or roll.

The method of the invention is most preferably applied to nickel foils, copper foils, iron foils and alloy foils based on these metals up to a thickness of about 125 μm.

The metal foil perforation apparatus according to the present invention includes a tank containing an electrolytic etching solution, an endless belt or roll having a surface inert to the electrolyte, and one of the metal foils to be perforated by passing through the tank. a perforated titanium mask supported such that one side of the mask is in contact with the surface of said endless belt or roll and the other side of the mask is in contact with the titanium mask; and a device for supplying current to the metal foil to be perforated.

The endless belt or roll is preferably made of or covered with a non-conductive flexible material such as rubber.

During perforation, the foil passes over the roll surface while contacting at least 50 degrees of the circumference of the large radius roll.

A typical roll radius using a 4 μm thick foil is 15 cI'rL.

The shape of the cathode preferably corresponds to the belt or roll so that the distance between the foil and the cathode remains constant during most of the time the foil passes through the electrolytic bath.

The spacing between the cathode and the anode is preferably less than 20 mm, typically about 2 mm.

Preferably, the cathode has a plurality of holes regularly located along its length and is connected to a manifold that supplies an electrolyte. can be pumped into the hole to inject the electrolyte onto the exposed surface of the foil through the mask.

An endless belt-shaped titanium mask is perforated in the desired array by photo-mechanical etching techniques.

A preferred example of the above etching technique is to first thoroughly clean a titanium strip, dip coat it with a light-resistant material, air dry it, and bake it.

The coated titanium is then inserted in contact between two identical optical masks connected to the resistor;
Expose both sides.

The exposed mask is then developed to remove the unexposed light resist, and the mask is then baked and etched on both sides until the perforations are completely formed.

To compensate for the cutout in the etching process, the dots on the optical mask are reduced in size by an amount equal to the cutout amount.

Next, the light resistor is removed with a solvent, the mask surface is cleaned, the length is trimmed, and spot welding is performed to create an endless belt.

In a preferred apparatus for carrying out the method of the invention, the titanium mask is preferably suspended on three or more rotatable rolls, at least one of which is suspended during the passage of the foil through the electrolytic bath. Preferably, it is adjustable or spring-loaded so that the mask is held tightly against the foil.

The drive takes place on one of the rolls on which the mask is suspended, and the friction between the foil and the mask allows the foil to be displaced.

Bearing friction increases the pressure between the mask and the foil in contact with the inert belt or roll.

Electrical current is supplied to the foil as it passes over a current supply roll positioned in front of an inert belt or roll, the belt or roll itself being made of a conductive material such as titanium. In some cases, current can be supplied to the foil from the belt or roll.

The method of the present invention can be used with any suitable etching bath, and typical electrochemical-mechanical electrolytes are particularly suitable.

Drilling of nickel foils requires highly concentrated chloride electrolytes to achieve good perforation without passivation.

To prevent passivation, if the electrolytic bath is not stirred,
A very low pH value is also required, ie pH=about 1.

Forced circulation of the electrolyte generally increases the drilling rate.

Preferred electrolytes in producing perforated nickel foils have a pH of about 1 to 7, preferably about 4 to 6.
% sodium chloride solution.

If the pH value is too high, nickel will precipitate as hydroxide and if allowed to accumulate in the chloride electrolyte,
This hydroxide is deposited on the titanium mask.

Since this phenomenon is undesirable for long-term operation, it is desirable to continuously decompose the nickel hydroxide precipitated from the thorium chloride electrolyte when employing the above pH values.

At low pH values, nickel is kept in solution and cannot be deposited on the cathode if its concentration is limited, for example by ion exchange techniques.

The potential on the surface of the titanium mask is approximately -1, at which immediate corrosion occurs.
It is important not to exceed 0V.

Such erosion only occurs if complete passivation of the foil occurs, for example due to failure of pump circulation of the electrolyte or failure of the foil drive.

When carrying out the method of the invention, a device should preferably be provided for automatically stopping the power supply to the foil in the event of a pump failure.

Surprisingly, it has been found that the method of the invention requires less current for drilling than the theoretical value.

Etching tends to occur from the outside of the wheel inward, and the hole in the foil usually results in a small disk of metal foil falling off.

Therefore, the current theoretically required to dissolve the center of the hole is not actually utilized.

Although the method of the present invention can be carried out at a current density of about 100 A/dm2, it is preferable to use a current density as high as possible, and when perforating a foil with a thickness of 4 μm, about 600 A/dm2 is suitable. There is.

Higher current densities can be employed, but the perforation rate depends on the current carrying capacity of the foil.

The perforated foil is withdrawn from the electrolytic bath, passed through a suitable washing bath, and then dried by passing into an oven.

Thin metal foils develop wrinkles due to normal air convection in the atmosphere in which the device is installed.

However, the occurrence of wrinkles can be prevented by cooling the foil leaving the oven with a jet of air, inserting a tissue into the cooled foil, and winding it onto a take-up reel.

The method of the present invention is effective in manufacturing metal foils having holes with a radius of up to about 6Tt7IL with a perforation rate of up to 50%, and is particularly effective for manufacturing storage batteries as exemplified in British Patent No. 1246048. It is useful as a method for manufacturing perforated foils when manufacturing electrodes.

The method of the invention will be explained with reference to the accompanying drawings, which diagrammatically show the apparatus for its implementation, but the invention is not limited thereto.

A nickel foil 1 with a thickness of 4 μm is supplied from a supply reel 2 and is sequentially supplied to a current supply roll 3, a guide roll 4, a rubber-covered large radius roll 6 and a guide roll 5.

The large radius roll is installed so that the foil can contact more than about 50% of the circumference of the roll.

The titanium mask 7 is an endless belt made of an annealed titanium strip 100 .mu.m thick with holes drilled into the desired hole pattern using the opto-mechanical etching technique described above.

Titanium mask 7 is suspended between rolls 8, 9 and 10, roll 10 being adjustable to hold the titanium mask firmly against the nickel foil passing between mask 7 and roll 6. The roll 10 is set so that

Rolls 6.8.9 and 10 are housed in a polymethyl methacrylate tank (not shown) 3 The foil 1 is transferred by friction between the titanium mask 7, which is transferred to the motor-controlled roll 9 driven by.

The nickel cathode 11 has a shape corresponding to the curvature of the roll 6 and is located facing the titanium mask 7.

The cathode 11 is provided with a series of holes along its axis of symmetry, and the cathode is connected to an electrolyte manifold 12.

A suitable electrolyte, such as a 20% chloride solution with a pH of 1 to 5, is then jetted through the manifold.

The distance between the cathode and the foil is about 2 mm.

The electrolyte overflowing from the end of the cathode is collected in a tank, passed through a suitable ion exchange resin to remove nickel ions if necessary, and then recycled through a suitable pump.

The current and the rate of passage of the foil are adjusted to ensure proper perforation.

Typically, a potential difference of about 5 μm will reduce the speed of passage of the foil by 10 μm.
At 0 M/hr, it gives a current density of about 600 A/dm2.

Perforated nickel foil fits the slipping clutch (
The film is sent to the remaining finishing steps by a take-up reel 13 driven through a winding reel 13 (not shown).

That is, the perforated foil is sent to a tank 14 containing a suitable cleaning solution such as 10% HC7, then passes through a water washing step 15, and then a drying oven 16 heated with eight 250 watt silica infrared heaters. sent to.

The foil that comes out of the oven is cooled to room temperature by a compressed air jet 17, and then a tissue supplied from a roll 18 is inserted and wound onto a take-up reel 13.

The guide rolls used in the device employ conventional means for arranging the foils.

[Brief explanation of the drawing]

The drawing diagrammatically shows the device of the invention. 1; nickel foil, 2; foil supply reel, 3; current supply roll, 3; guide roll, 5; guide roll, 6; large radius roll, 7; titanium mask, 8, 9, 10; titanium mask tension roll, 11; Nickel cathode, 12
; Electrolyte manifold, 13; Take-up reel, 14; Washing tank, 15; Water washing device, 16; Drying oven, 17
; Compressed air blowing device, 18: Tissue roll.

Claims (1)

[Claims] 1. One side of a long metal foil is brought into contact with an endless surface that is inert to the electrolyte, and the other side of the metal foil is brought into contact with an endless perforated titanium mask. The length of metal foil is passed through an electrolytic etching bath while in contact, and the bath is removed through the perforated mask by applying a potential difference of less than 10 V between the metal foil and the cathode immersed in the bath. Remove the metal foil exposed to the liquid.
A method for producing perforated long metal foils comprising anodic etching. 2. The method of claim 1, wherein the metal foil is a foil made of nickel, copper, iron or alloys based on these and having a thickness of up to about 125 μm. 3. The method according to claim 1 or 2, wherein the endless surface is a roll with a large radius, and the metal foil is brought into contact with at least 50% of the circumference of the roll. 4. The method according to claims 1 to 3, wherein the nickel foil is perforated in a chloride bath having a pH of 1 to 7 while stirring the bath liquid. 5. The method according to claim 4, wherein the electrolytic solution is stirred by forced circulation and the pH of the electrolytic solution is determined. 6. The method of claims 1 to 5, wherein the current density is maintained at about 600 people/dm2. 7. A method according to claims 1 to 6, in which the perforated metal foil is washed, dried and then cooled with an air jet to prevent wrinkles from forming. 8 A tank containing an electrolytic etching solution, an endless belt or roll having a surface inert to the electrolyte, and one side of a metal foil that passes through the tank and is perforated to form the endless belt. or a perforated endless titanium mask in contact with the surface of the roll and supported with the other side in contact with the titanium mask, with a cathode located remote from, but close to, the titanium mask to be perforated. A metal foil perforation device comprising a metal foil and a device for supplying electric current to the metal foil. 9. Device according to claim 8, in which the endless belt or roll is made of or covered with a non-conductive flexible material. 10. Apparatus according to claim 8 or 9, wherein the shape of the cathode corresponds to the shape of the belt or roll and the cathode is located at a distance of less than 20 cm from the belt or roll. 11 A manifold for supplying electrolyte such that the cathode has a plurality of holes along its length and the electrolyte pumped through the holes is injected through the mask onto the surface of the exposed metal foil. 11. The apparatus according to claim 10, wherein said cathode is connected to said cathode.