JPS5897255A - Manufacture of packing for dry battery - Google Patents

Abstract

PURPOSE:To prevent leaking of an electrolyte to the outside of a dry battery to increase electrolyte leakage resistance by using paper obtained by immersing it in a molten water-repellant material such as paraffin, wax under a reduced pressure after drying. CONSTITUTION:Paper having a density of 0.4-0.8g/cm<3> and a basis weight of 200-800g/m2 is desirable. The paper while is over this range is too hard, and even after impregnation of paraffin or wax it has insufficient softness in order that it keeps liquid-tight contact with parts such as an anode terminal plate. The paper which is bellow this range has good contact with parts but decreases mechanical strength, thus workability such as supply of parts is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a paper backing used in a press-fit sealing portion of a dry battery.

The figure shows an example of a typical cylindrical dry cell structure.
S mixture 3 and I# purple zelkova 4 are inserted, a synthetic resin *m sealing body 6 is attached to the upper end opening of the zinc can 1, and an anode terminal plate 6 and an annular ring are attached to the bottom of the zinc can 1. Puff King T is provided. Then, a heat-shrinkable resin tube 8 is inserted into the trench from the six sealing bodies to the outer edge of the backing 7.
The metal jacket 9 is then fitted and the upper end thereof is fastened to the outer edge of the anode terminal plate 10 on the upper surface of the sealing body 6, and the lower end is fastened to the outer edge of the backing 7. Generally adopted.

In a dry battery having such a structure, the backing 7 is
It is an important rounding part that retains the electrolyte that has come out of the TL lead can 1 (due to electrical discharge) inside the heat-shrinkable tube 8, and prevents the electrolyte from penetrating. However, as a result of various experiments conducted by the present inventors, it was found that the above impregnation treatment resulted in the penetration of the electrolyte into the backing γ due to the capillary action of the paper. It has been found that this has a significant effect on the leakage resistance performance of dry batteries.

The present invention has been made based on the above-mentioned knowledge, and its purpose is to improve the leakage resistance performance of dry batteries by perfecting the water repellency of the paper backing. This book also attempts to improve the storage performance of dry batteries.

That is, the method for manufacturing a dry battery backing of the present invention includes:
It is characterized by drying K in advance and then immersing it in a heat-meltable water-repellent substance such as paraffin or wax in a reduced-pressure atmosphere to impregnate it with the water-repellent substance. can be impregnated into the interfiber voids of the paper to a completely saturated state, resulting in a backing in which there is no penetration of the electrolyte.

The paper used here is 4 to 0.8 f/n
Pr'', basis weight ff1oo~800f, it is desirable that it is in the range of 1000F.If these upper limits are exceeded, the material itself will become too hard and the paraffin and Lux rumors will be impregnated with saturated sh and have poor flexibility. As a result, liquid-tight contact with parts such as the cathode terminal plate cannot be maintained.Also, if the above lower limit is exceeded, the adhesion with the parts will be better, but the mechanical strength will be weakened, such as weakening of !lI. This results in a significant decline in work efficiency such as parts supply.

Next, specific examples of the present invention will be described.

Example: Using kraft paper with a density of α6fΔ♂9 tsubodo 4 ao ty&, it was pre-dried at a temperature of tto℃ for 6 minutes or more to sufficiently remove adhering moisture, and then dried at 100 to 30mH.
The paper was left in a reduced pressure atmosphere of
[l Immerse in heated paraffin bath for 5-10 seconds. After that, the reduced pressure is released to return to normal pressure, and the process is completed.

Table 1 shows actual measurements of Perafin impregnation rates of backing papers treated by various methods, including (A) treated paper obtained in the above example in which Fi dry treated bales were impregnated under reduced pressure, (B) (C) is a reference example, treated paper impregnated under reduced pressure without drying, and (C) is a reference example.
Treated paper was impregnated under normal pressure after drying. (D) is a treated paper that was impregnated under normal pressure without drying, as it is used for conventional backing for dry cell batteries.

! 11 As is clear from Table 1, the treated paper (A) according to the above example has a significantly higher paraffin impregnation rate than the conventional treated paper (D) and is almost saturated. . The theoretical value of paraffin impregnation rate in saturated state 11 is 4tL2
%.

Next, Table 2 shows 16M from each treated paper of (A) to (D) above.
80 ×6olIII test pieces were formed.

The bottom 10m of this is covered with an electrolytic solution (70% water by weight, ZmCj
25% by weight, 5% by weight of NH4Cl) for 16 days, and then boiled the tip @1 om in pure water to qualitatively determine the presence or absence of electrolyte penetration using AfNO. This is the result.

Table 2 As described above, in the treated paper (Mu), no penetration of the electrolytic solution due to capillarity between paper fibers was observed.

Next, a comparison test was conducted between a cylindrical battery (1) using a backing formed from the treated paper (mum) of the above example and a cylindrical battery (1) using a conventional packing. I got the following results.

(1) l! The results shown in Table 3 were obtained as the leakage resistance performance in O overdischarge.

11g (2) 4eResults of 4 were obtained for the discharge performance of Shieri stored in an atmosphere at 1°C for δ months.

As is clear from the above description, the dry battery backing according to the present invention can completely prevent leakage of electrolyte to the outside and improve the leakage resistance of the dry battery.
Furthermore, the backing improves the airtight effect and prevents the water mixture from evaporating and escaping, thereby suppressing performance deterioration during storage of the dry battery, as shown in Table 4.

[Brief explanation of drawings]

The figure is a sectional view showing a typical structural example of a cylindrical dry battery. 1-Zinc can a...Adjacent mixture 4...Carbon rod 6--Cathode terminal plate 7-Backing 8-Heat shrinkable tube 9-Metal jacket

Claims (2)

[Claims] (1) Dry the paper in advance, then immerse it in a bath of a heat-meltable water-repellent substance under reduced pressure to make the paper repellent by 4 tons.
A method for producing pubking for dry batteries, characterized by impregnating it with hI quality. (2) The method for producing puffing for dry batteries according to claim 1111, wherein the paper has a density of $0.4 to α8 f/cps and a basis weight of 200 to 1,500 f.