Patent GB-665262-A (GB)
Title: Improvements in methods of polymerising or condensing chemical substances
IPC: C08F2/46
Filed: 1947-07-29
Abstract: Substances to be polymerized or condensed are irradiated with high speed electrons having a velocity equivalent to more than five hundred kilovolts.  The irradiation should be carried out during one or more short periods lasting less than 10-1 seconds.  The substance may be placed in an electron permeable container as an aqueous emulsion and may be heated to say 50 DEG  C. or cooled to say 0 DEG to -80 DEG  C.  The substance may be irradiated with stirring with or without the usual catalysts in the presence of air or inert gas, or in partial vacuum or under pressure, e.g. 200 p.s.i.  The substance may be treated in the presence of "contact materials" which facilitate the polymerization during irradiation but terminate it after irradiation, e.g. elements of the second or third groups of periodic table and their compounds particularly oxides of aluminium, magnesium, or zinc, or magnesium carbonate.  0.1-1 per cent of the "contact material" may be used and 2-50 times the initial amount may be added to terminate the polymerization.  The substances may include fillers such as mica, magnesium sulphate, silicon oxide, wood pulp, shredded cellulose from corn husks, linen fibre and wool fibre. Products include phenol-aldehyde resins; urea-aldehyde resins, phenol-furfural resins; melamine-formaldehyde resins; alkyd resins; amine resins; cellulose plastics such as cellulose acetate; vinyl resins such as polymers of vinyl alcohol, chloride, or acetate, vinylidene chloride, vinyl butyral, vinyl formal; acrylic resins such as polymers of methyl methacrylate, acrylic esters; polyfluoroethylene; polyethylene sulphides; polymers of isoprene and butadiene, and their copolymers with vinyl compounds, chlorinated hydrocarbons, alcohols, ethers, aldehydes, ketones such as methylbenzyl ketone, acrylic resins, and isobutylene; copolymers of chloroprene with vinyl compounds; polymers of acids such as succinic, oxal-acetic, cyanoacetic, tartaric, sebacic, and of amines such as propylene diamine. hexamethylene tetramine, and butylene diamine. The source of radiation and the container should be of the type described in Specification 673,924, [Group III].  In Examples: (1) methyl methacrylate is exposed in an irradiation chamber in an inert atmosphere at 20 DEG  C. to 4 million "rep" in the form of electrons having a velocity of 1,500 kilovolts.  After irradiation the liquid is transferred to a storage vessel in which polymerization is continued by standing at 25 DEG  C. for 1 1/2 -2 hours, and the product is worked up to a clear polymer; (2) a mixture of vinyl chloride, vinyl acetate, and ethyl acetate is emulsified in water and 1 per cent aluminium oxide is added.  The slurry is recycled with nitrogen under pressure through a tube having an electron-permeable window at 60 DEG  C. and exposed to electron radiation until 12 million "rep" have been absorbed.  Fifteen times the amount of aluminium oxide is added to terminate polymerization, and ethyl acetate, and the mixture filtered.  The copolymer is precipitated from the filtrate by addition of ethanol; (3) vinyl chloride is polymerized in the presence of barium peroxide.  The Specification as open to inspection under Sect. 91 comprises also irradiation with neutrons, and irradiation to effect separation after polymerization. This subject-matter does not appear in the Specification as accepted.ALSO:Substances to be polymerized or condensed are irradiated with high speed electrons having a velocity equivalent to more than five hundred kilovolts.  The irradiation should be carried out during one or more short periods lasting less than 10-1 sec. The substance may be placed in an electron permeable container as an aqueous emulsion and may be heated to say 50 DEG C. or cooled to say 0 DEG  to -80 DEG C.  The substance may be irradiated with stirring with or without the usual catalysts in the presence of air or inert gas, or in partial vacuum or under pressure, e.g. 200 p.s.i. The substance may be treated in the presence of "contact materials" which facilitate the polymerization during irradiation, but terminate it after irradiation, e.g. elements of the second or third groups of the periodic table and their compounds particularly oxides of aluminium, magnesium, or zinc, or magnesium carbonate.  0.1-1 per cent of the "contact material" may be used and 2-50 times the initial amount may be added to terminate the polymerization.  The substances may include fillers such as mica, magnesium sulphate, silicon oxide, wood pulp, shredded cellulose from corn husks, linen fibre and wool fibre. Products include phenolaldehyde resins; urea-aldehyde resins; phenol-furfural resins; melamine-formaldehyde resins; alkyd resins; amine resins; cellulose plastics such as cellulose acetate; vinyl resins such as polymers of vinyl alcohol, chloride, or acetate, vinylidene chloride, vinyl butyral, vinyl formal; acrylic resins such as polymers of methyl methacrylate, acrylic esters; polyfluoroethylene; polyethylene sulphides; polymers of isoprene and butadiene, and their copolymers with vinyl compounds, chlorinated hydrocarbons, alcohols, ethers, aldehydes, ketones such as methyl-benzyl ketone; acrylic resins, and isobutylene; copolymers of chloroprene with vinyl compounds; polymers of acids such as succinic, oxal-acetic, cyanoacetic, tartaric, sebacic, and of amines such as propylene diamine, hexamethylene tetramine, and butylene diamine. The source of radiation and the container should be of the type described in Specification 673,924.  The Specification as open to inspection under Sect. 91 comprises also irradiation with neutrons, and irradiation to effect separation after polymerization.  This subject-matter does not appear in the Specification as accepted.