GB642744A - Improvements in or relating to porous pots for primary electric cells - Google Patents

Abstract

A porous pot for a primary electric cell is made from a mixture of a fibrous or powdered material and a binder consisting of a natural or synthetic thermoplastic or thermosetting resin such as rosin or a resin made from a formaldehyde compound of urea, phenol, cresol, or melamine. The fibrous material may be wood pulp, straw, manilla, esparto, kapok, bagasse, cotton, wool, asbestos, glass fibres or nylon. The pot may be made by felting from a pulp of fibrous material prepared by beating wood pulp or other paper-making fibres, the felting being effected by deposition by suction on a perforated former. Alternatively the fibres may be pressed into the required shape. The binder may be incorporated in the fibrous material before felting or pressing, or the shaped pot may be impregnated with a solution of the binder in a mixture of alcohol and water which may contain sodium hydroxide and sodium chloride, or alcohol with acetone and a solution of sodium hydroxide. Electrolytes such as sodium hydroxide, ammonium hydroxide, ammonium bromide, calcium hydroxide, ammonium chloride and sodium chloride may be incorporated in the fibrous material or binder. The finished pot may be subjected to a steam treatment at a pressure above 25 lbs. per sq. inch. The upper part of the pot may be rendered non-porous by an application of binding material. Two examples of the process are given in the Specification. Specification 441,327, [Group XXXVI], is referred to.ALSO:A porous pot for a primary electric cell is made from a mixture of a fibrous or powdered material and a binder consisting of a natural or synthetic thermoplastic or thermosetting resin such as rosin or a resin made from a formaldehyde compound of urea, phenol, cresol or melamine. The fibrous material may be wood pulp, straw, manilla, esparto, kapok, bagasse, cotton, wool, asbestos, glass fibres or nylon. The pot may be made by felting from a pulp of fibrous material prepared by beating wood pulp or other paper-making fibres, the felting being effected by deposition by suction on a perforated former. Alternatively, the fibres may be pressed into the required shape. The binder may be incorporated in the fibrous material before felting or pressing, or the shaped pot may be impregnated with a solution of the binder in a mixture of alcohol and water which may contain sodium hydroxide and sodium chloride, or alcohol with acetone and a solution of sodium hydroxide. Electrolytes such as sodium hydroxide, ammonium hydroxide, calcium hydroxide, ammonium chloride, ammonium bromide and sodium chloride may be incorporated in the fibrous material or binder. The finished pot may be subjected to a steam treatment at a pressure above 25 lbs. per sq. in. The upper end of the pot may be rendered non-porous by an application of binding material. Two examples of the process are given in the Specification. Specification 441,327, [Group XXXVI], is referred to.