Imperial Chemical Industries Limited

Thorn Electrical Industries Limited

Anthony Peter Downing

John Michael Rees

Christopher Arthur Horler

Richard Llewellyn Powell

The invention relates to the manufacture of electric lamps containing fluorine in their gas fill. Fluorine can be accurately and conveniently introduced into an electric lamp envelope in the form of a fluorocarbon polymer. If a soluble fluorocarbon polymer, such as a degraded PTFE, is dissolved in a suitable solvent, for example a fluorine-substituted hydrocarbon or halocarbon solvent, the resulting solution can be metered with great accuracy into the lamp envelope and the solvent subsequently evaporated. The invention avoids the difficulties otherwise inherent in dispensing accurate quantities of an extremely reactive gaseous material.

Method of introducing fluorine into a lamp

Manufacture of electric lamps

An additive for imparting soil-release or anti-soiling characteristics to a textile comprising a copolymer formed by the chemical condensation of (A) an organic compound having a plurality of carboxylic anhydride groups, and (B) a bifunctional compound, each functional group being condensible with the anhydride groups of (A) and also containing a terminal fluorocarbon group of at least 3 carbon atoms.

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Runcorn, United Kingdom

Anthony Peter Downing