Patent GB-580742-A (GB)
Title: Production of sheets and other shaped articles from disintegrated leather and/or other fibrous and/or finely divided materials and natural or synthetic rubbers
IPC: C04B26/02
Filed: 1943-09-29
Abstract: Sheets and other shaped articles are prepared by working into a natural or artificial rubber, on a mill or in an internal mixer, an aqueous slurry of a fibrous and/or finely-divided material, e.g. disintegrated leather, cotton, cork dust, wood meal, asbestos, until a homogeneous mix is obtained, and then forming the mix into the desired shapes.  Any natural or synthetic rubber or rubber-like material which can be worked into a water-in-rubber dispersion can be used, e.g. the organic di-isocvanate modified polyesters or polyester amides described in Specifications 553,733 and 580,524.  The rolls of the mill, which may or may not be heated, are adjusted so that the rubber forms a continuous band, or the rubber may be worked in an internal mixer, a dispersing-agent or hydrophilic colloid being added if necessary. The slurry is added, slowly at first, and the working is continued until much of the water is squeezed out and a homogeneous mix results.  Vulcanizing agents, accelerators, fillers, pigments, anti-oxidants, stabilizers and softening and dispersing agents may be added.  According to examples: (a) an organic diisocyanate modified polyester amide prepared according to example 7 of Specification 580,524 is run on a two-roll mill at about 50 DEG C. and a slurry of finely-disintegrated leather or leather and cotton in water is added in small quantities until a mass consisting of water and fibre dispersed in rubber is obtained, when the remainder of the slurry can be added in larger quantities, milling being continued to produce an almost continuous sheet at which stage a curing-agent such as ammonium dichromate is added; (b) a slurry of leather and asbestos is added instead of the slurry of example (a), and castor oil is added at the final stage instead of ammonium dichromate, (c) a slurry of finely-disintegrated vegetable-tanned leather scrap and cotton in water is milled into pale crepe rubber.ALSO:Sheets and other shaped articles are prepared by working into a natural or artificial rubber, on a mill or in an internal mixer, an aqueous slurry of a fibrous and/or finely divided material, e.g., disintegrated leather, cotton, cork dust, wood meal, asbestos, or the like, until a homogeneous mix is obtained, and then forming the mix into the desired shapes.  Any natural or synthetic rubber or rubber-like material which can be worked into a water-in-rubber dispersion can be used, e.g., the organic di-isocyanate modified polyesters or polyester amides described in Specifications 553,733 and 580,524 (both in Group IV).  The rolls of the mill, which may or may not be heated, are adjusted so that the rubber forms a continuous band, or the rubber may be worked in an internal mixer, a dispersing-agent or hydrophilic colloid being added if necessary. The slurry is added, slowly at first, and the working is continued until much of the water is squeezed out and a homogeneous mix results.  Vulcanizing-agents, accelerators, fillers, pigments, anti-oxidants, stabilizers, and softening and dispersing agents may be added.  According to examples, (a) an organic di-isocyate modified polyester amide prepared according to example 7 of Specification 580,524, [Group IV], is run on a two-roll mill at about 50 DEG C. and a slurry of finely-disintegrated leather or leather and cotton in water is added in small quantities until a mass consisting of water and fibre dispersed in rubber is obtained when the remainder of the slurry can be added in larger quantities, milling being continued to produce an almost continuous sheet at which stage a curing-agent, such as ammonium dichromate is added; (b) a slurry of leather and asbestos is added instead of the slurry of example (a), and castor oil is added at the final stage instead of ammonium dichromate; (c) a slurry of finely-disintegrated vegetable tanned leather scrap and cotton in water is milled into pale crepe rubber.