Patent GB-719102-A (GB)
Title: Improvement in foamed materials
IPC: C08J9/10
Filed: 1952-03-11
Abstract: Closed-cell gas expanded cellular products are prepared by adding to synthetic rubbers or resins an organic carbonyl azide of formula <FORM:0719102/IV (a)/1> where R is an organic radical and n is 1, 2 or 3 and heating to decompose the azide.  Specified synthetics are butadiene 1:3 polymer and copolymers with the acrylates, vinyl pyridine, acrylonitrile or styrene, polyalkylene sulphides, butyl rubber, ethyl acrylatechlorovinyl ether, polystyrene, polyethylene, polyvinyl acetal and butyral, polyacrylates, polymethacrylates, polyvinyl chloride and vinyl chloride copolymer resins particularly those with diethyl maleate or fumarate, vinyl acetate, or vinylidene chloride and urea formaldehyde.  Specified azides are phenyl carbonyl azide, p-tert-butyl benzoyl azide, o-, m-, and p-nitro benzoyl azide, p-methyl benzoyl azide, m- and p-chloro benzoyl azide, o-, m, and p-hydroxybenzoyl azide, p-methoxy benzoyl azide, p-ethoxy benzoyl azide, isovaleric azide, pivalic azide, lauroyl azide, palmitoylazide, stearoyl azide, succinyl azide, malonylazide, adipyl azide o-, m- and p-phthalyl diazide, pyromucyl azide, pyrrole-2-carbonyl azide, p-cinchonynyl azide, and thiophene-2-carbonyl azide.  These azides decompose to yield isocyanates which may be neutralized by the presence of compounds containing an active hydrogen, e.g. methyl, ethyl, propyl, isopropyl, amyl, hexyl, nonyl, lauryl alcohols, phenol, cresol, resorcinol ethylene glycol, acetic acid, propionic, butyric or stearic acids or water.  Plasticizers, pigments, stabilizers, curing agents, accelerators activators, and loading agents may also be present.ALSO:Organic carbonyl azides of structural formula R.(CO.N3)n in which R is an organic radical and n is 1, 2 or 3, are prepared by converting the corresponding acid to the hydrazide which is then treated with nitrous acid to form the azide, or by treating the corresponding acid chloride with dry or an aqueous solution of sodium azide.  The preparation of p-tertiary butyl benzoyl azide is described and aliphatic and aromatic carbonyl azides and diazides as well as heterocyclic azides are disclosed.ALSO:Closed-cell gas expanded cellular natural rubber is prepared by adding to natural rubber an  organic carbonyl azide of formula <FORM:0719102/V/1> n where R is an organic radical and n is 1, 2 or 3, and heating to decompose the azide.  Specified benzoylazides: p-tert.-butyl, o-, m- and p-nitro, p-methyl, m and p-chloro, o-m and p-hydroxy, p-methoxy and p-ethoxy, isovalericazide, purilicazide, lauroyl azide, palmitoyl azide, stearoyl azide, succinyl azide, malonyl azide, adipylazide, o-m and p-phthalyl diazide, pyrovinylazide, pyrrol-2-carbonyl azide, p-cinchonynyl azide, and thiophene-2-carbonyl azide.  These azides decompose to yield isocyanates which may be neutralized by the presence of compounds containing an active hydrogen, e.g. methyl, ethyl, propyl, isopropyl, amyl, hexyl, nonyl or lauryl alcohols, phenol, cresol, resorcinol, ethylene glycol acetic, propionic butryric or stearic acid or water.  Plasticizers, pigments, stabilizers, curing agents, accelerators, activators, and bonding agents may also be present.