Patent GB-476864-A (GB)
Title: Improvements in or relating to compositions of comminuted cork and a binder
IPC: C08L97/00
Filed: 1936-04-16
Abstract: A cork composition comprises comminuted cork in predominating amount by volume and a binder comprising an adhesive and a fatty drying oil (e.g. tung oil) in gelled condition, the gelled oil being formed by first reacting the oil with an amine and then reacting the product under heat with a polyhydric alcohol and a polycarboxylic acid anhydride.  In a modification, the adhesive is omitted and the oil-amine product is reacted with a mixture of the anhydride and alcohol in which reaction has been initiated to form a liquid resinous body.  The adhesive may be (1) a natural resin (kauri, elemi, dammar); (2) a synthetic resin (a stage phenol formaldehyde, urea formaldehyde or a mixture of the two); (3) albumen, casein or glue, (e.g. as a glue gel, i.e. glue mixed with a polyhydric alcohol such as glycerine or a glycol); (4) rubber latex; or (5) mixtures of these, e.g. latex and glue, latex and resin, or latex, resin and glue.  The anhydride may be phthalic succinic, malic or maleic; e.g. as molten maleic anhydride crystals dissolved in glycerine or glycols.  The composition may include waxes, fats, a gluetanning agent such as formaldehyde, and a bleaching agent, e.g. oxalic acid which, it is stated, will accelerate the setting of the resin when used.  The cork may be sprayed with the binder, molten wax or fat being then added to the mixture; the composition may then be compressed in moulds, extruded or sheeted under heat, or heated after extrusion &c. in an oven to 240 DEG  F., and sliced into sealing discs for bottle caps to which may be applied facings of metal foil or other material, or made into printing press blankets, with or without an overlay, or used as sealing liners and packing material in general.ALSO:A cork composition comprises comminuted cork in predominating amount by volume and a binder comprising an adhesive and a fatty drying oil (e.g. tung oil) in gelled condition, the gelled oil being formed by first reacting the oil with an amine and then reacting the product under heat with a polyhydric alcohol and a polycarboxylic acid anhydride.  In a modification the adhesive is omitted and the oil-amine product is reacted with a mixture of the anhydride and alcohol in which reaction has been initiated to form a liquid resinous body.  The adhesive may be (1) a natural resin (kauri, elemi, dammar), (2) a synthetic resin (A stage phenol formaldehyde, urea formaldehyde or a mixture of the two), (3) albumen, casein or glue, (e.g. as a glue gel, i.e. glue mixed with a polyhydric alcohol such as glycerine or a glycol), (4) rubber latex or (5) mixtures of these, e.g. latex and glue, latex and resin, or latex, resin and glue.  The anhydride may be phthalic, succinic, malic or maleic, e.g. as molten maleic anhydride crystals dissolved in glycerine or glycols.  The composition may include waxes, fats, a glue-tanning agent such as formaldehyde, and a bleaching agent, e.g. oxalic acid which, it is stated, will accelerate the setting of the resin when used.  The cork may be sprayed with the binder, molten wax or fat being then added to the mixture; the composition may then be compressed in moulds, extruded or sheeted under heat, or heated after extrusion &c. in an oven to 240 DEG  F., and sliced into sealing discs for bottle caps to which may be applied facings of metal foil or other material, or made into printing press blankets, with or without an overlay, or used as sealing liners and packing material in general.