SEALING MATERIAL FOR ALKALINE BATTERY

摘要

PURPOSE:To obtain an alkali-proof sealing material having a great sealing effect against external load by adding a styrene-butadiene block copolymer to blown asphalt. CONSTITUTION:After a battery lid 3 is attached to a battery container 1, a sealing material 6 is packed between the container 1 and the lid 3 to bind them together by sealing. Either a mixture prepared by combining blown asphalt with a styrene-budadiene block copolymer having a higher softening point than blown asphalt or a mixture prepared by adding a wax to the above mixture is used as the sealing material 6. The styrene-budadiene block copolymer works as a hot- melt-type adhesive. Therefore the ductility of the sealing material 6 increases and an increased resistance to texternal load is achieved as the percentage of the copolymer in the sealing material increases. However, in order to avoid difficulty in sealing resulting from increased viscosity of the sealing material 6 caused when it is molten at around 180 deg.C, the proper proportion of the copolymer is 5-35wt% of the sealing material 6. Addition of a wax increases the compatibility between the above adhesive and blown asphalt and is specially advantageous when a increased amount of the adhesive is used.