Patent GB-417999-A (GB)
Title: Improvements in or relating to the polymerisation of organic compounds
IPC: C08F20/50
Filed: 1933-04-12
Abstract: <PICT:0417999/III/1> Apparatus for the polymerization of methacrylonitrile or mixtures containing it, consists of a container with one or more walls made of flexible material which can conform to any alteration in the external form of the mass undergoing polymerization.  The apparatus may be made of rubber or regenerated cellulose, if desired with a backing of metal foil, supported by but unattached to a surrounding framework or vessel. Alternatively the walls of the vessel may be built up of sheets of rubber or similar flexible material clamped at their joining edges.  For heating the contents, the vessel may be placed in a metal or other container, care being taken to prevent the walls of the vessel from sticking to the container, e.g. by dusting them with a powder such as graphite or French chalk.  The inner surfaces may be coated with a substance which minimizes sticking of the polymerization mixture or which minimizes solvent or other action.  In one form of apparatus the bottom of the vessel is formed of rigid material and the other walls are detachably clamped to it and to each other.  If desired the flexible walled container may be formed in situ, e.g. on the inner walls of a metal vessel, e.g. by coating the walls of the vessel with graphite or French chalk and spraying it with a coat or coats of rubber or gelatine solution.  In the form of apparatus illustrated, a rectangular metal vessel 15, provided with a valve 19 by means of which the pressure in the vessel may be reduced, is fitted with a lining 21 of metal foil and inside this is a lining 22 of regenerated cellulose, e.g. from viscose, or of cellulose acetate.  At the bottom of the lining is placed an aluminium base plate 23 with dovetail grooves 24 and recesses 25.  The grooves form a key for the block of polymerized product and the recesses enable the base plate to be secured to the machine in which the polymerized block is subsequently sheeted or otherwise worked.ALSO:Solid polymerized products free from bubbles are manufactured by introducing unpolymerized methacrylonitrile or a mixture containing it, with or without the addition of <PICT:0417999/IV/1> polymerization catalysts, into a container with one or more walls made of flexible material which can conform to any alteration in the external form of the mass undergoing polymerization, and subjecting the contents to heat.  The apparatus may be made of rubber or regenerated cellulose, if desired, with a backing of metal foil, supported by but unattached to a surrounding framework or vessel.  Alternatively, the walls of the vessel may be built up of sheets of rubber or similar flexible material clamped at their joining edges.  For heating the contents, the vessel may be placed in a metal or other container, care being taken to prevent the walls of the vessel from sticking to the container, e.g. by dusting them with a powder such as graphite or French chalk.  The inner surfaces may be coated with a substance which minimizes sticking of the polymerization mixture or which minimizes solvent or other action.  In one form of apparatus, the bottom of the vessel is formed of rigid material and the other walls are detachably clamped to it and to each other.  If desired, the flexible walled container may be formed in situ, e.g. on the inner walls of a metal vessel, e.g. by coating the walls of the vessel with graphite or French chalk and spraying it with a coat or coats of rubber or gelatine solution.  In the form of apparatus illustrated, a rectangular metal vessel 15, provided with a valve 19 by means of which the pressure in the vessel may be reduced, is fitted with a lining 21 of metal foil and inside this is a lining 22 of regenerated cellulose, e.g. from viscose, or of cellulose acetate.  At the bottom of the lining is placed an aluminium base plate 23 with dove-tail grooves 24 and recesses 25. The grooves form a key for the block of polymerized product and the recesses enable the base plate to be secured to the machine in which the polymerized block is subsequently sheeted or otherwise worked. In examples: (1) a mixture of methacrylonitrile, coumarin, butyro- and valero-lactones and benzoyl peroxide is poured into a thin rubber bag which is dusted on the outside with graphite and placed in a metal container at 60 DEG  C.; (2) a mixture of methacrylonitrile, acetic anhydride and benzoyl peroxide is treated as in (1), except that French chalk is used for dusting the outside of the bag; (3) a mixture of methacrylonitrile, methyl methacrylate, dimethyl phthalate and benzoyl peroxide is poured into a vessel of the kind shown which is provided with a lining of metal foil, itself lined with material known under the Registered Trade Mark "Cellophane"; the lid is put on, the pressure reduced and the whole is heated to 55 DEG  C.