Patent GB-387671-A (GB)
Title: Improvements in or relating to the manufacture of goods of or containing rubber or similar material
IPC: B29C37/00
Filed: 1931-08-07
Abstract: The process of the parent Specification which comprises converting aqueous dispersions of rubber and the like into granular dispersions thereof by precipitating in situ filling ingredients by the interaction of water soluble reagents having normally no coagulating effect on the dispersions and coating articles with the granular dispersions to produce a surface ranging from a smooth matt to a coarse granular texture, is modified in that the granular dispersions are produced so that they contain little or no compounding ingredients by carrying out the coagulation by a variety of agents in the presence of a large quantity of water, with or without protective colloids.  The granular dispersions so produced are used to coat articles, as in the parent Specification, which are then dried. Examples of coagulants are acetic acid, sodium silicofluoride, aluminium chloride, potash alum, barium chloride, zinc acetate, zinc sulphate, magnesium acetate, magnesium sulphate, ferrous sulphate, ferric sulphate, nitric acid, hydrochloric acid, and sulphuric acid. Examples of restraining colloids are casein, glue, gum acacia and sodium aluminate.  The amount of colloid present, and the degree of concentration influence the state of division of the precipitate. The preferred concentration of the dispersion is less than 10 per cent total solids.  The emulsions comprise those of rubber, gutta-percha, balata, &c. occurring naturally or artificially obtained from coagulated rubber, vulcanized rubber, synthetic rubber, &c.  Articles are coated with the dispersions by dipping, spreading, or spraying.  Several examples of methods used to produce granular dispersions are given of which the following is typical. 4 c.cs. of a solution of glue or gum acacia are added to 100 c.cs. of natural latex diluted to contain 4 per cent total solids, together with 0.5 c.c. of a 20 per cent dispersion of sodium silicofluoride, and the whole stirred during the addition.  A granular dispersion is produced.  Specification 219,635, [Class 70, Indiarubber &c.], is referred to.ALSO:The process described in the parent Specification which comprises converting aqueous dispersions of rubber and the like into granular dispersions thereof by precipitating in situ filling ingredients by the interaction of water-soluble reagents having normally no coagulating effect on the dispersions and coating articles with the granular dispersions to produce a surface ranging from a smooth matt to a coarse granular texture, is modified in that the granular dispersions are produced so that they contain little or no compounding ingredients by carrying out the coagulation by a variety of agents in the presence of a large quantity of water, with or without protective colloids.  The granular dispersions so produced are used to coat articles, as in the parent Specification, which are then dried.  Examples of coagulants are acetic acid, sodium silicofluoride, aluminium chloride, potash alum, barium chloride, zinc acetate, zinc sulphate, magnesium acetate, magnesium sulphate, ferrous sulphate, ferric sulphate, nitric acid, hydrochloric acid, and sulphuric acid.  Examples of restraining colloids are casein, glue, gum acacia, and sodium aluminate.  The amount of colloid present, and the degree of concentration influence the state of division of the precipitate.  The preferred concentration of the dispersion is less than 10 per cent total solids.  The emulsions comprise those of rubber, guttapercha, balata, &c., occurring naturally or artificially obtained from coagulated rubber, vulcanized rubber, synthetic rubber, &c.  Articles are coated with the dispersions by dipping, spreading, or spraying.  Several examples of methods used to produce granular dispersions are given of which the following is typical: 4 ccs. of a solution of glue or gum acacia are added to 100 ccs. of natural latex diluted to contain 4 per cent total solids, together with 0,5 cc. of a 20 per cent dispersion of sodium silicofluoride, and the whole stirred during the addition. A granular dispersion is produced.  Specifications 219,635 and 290,313, [both in Class 70, Indiarubber &c.], are referred to.