GB955373A - - Google Patents

Abstract

955,373. Carbo-diimides. FARBENFABRIKEN BAYER A.G. June 1, 1962 [June 3, 1961], No. 21288/62. Heading C2C. [Also in Division C3] Acrylonitrile polymer solutions in organic solvents are shaped in the presence of one or more carbodiimides as stabilizer in an amount of 0À1 to 3% by weight based on the polymer. The stabilizers may be mono- or polycarbodiimides which in addition to carbodiimide groupings may contain hydrocarbon residues or hydrocarbon bridges which may in turn be substituted by halogen, alkoxy or carboxy residues or nitro groups. The preferred carbodiimides are 0,0<SP>1</SP>-substituted diphenyl carbodiimides of formula: where R 1 represents alkyl, aralkyl or alkoxy residues containing 1 to 18 carbon atoms, R 2 hydrogen, alkyl, aralkyl, halogen or carboxy residues, and R 3 , R 4 and R 5 hydrogen alkyl, alkoxy or halogen residues. These preferred carbodiimides may be prepared by the processes of Specification 851,936 or they may be prepared by heating the corresponding aromatic isocyanates substituted in the o-position in relation to the isocyanate group, in the presence of tertiary amines, basically reacting metal compounds, carbonates of metal salts or non- basic organometallic compounds at temperatures between 120‹ and 300 ‹C. The reaction is as follows: 2 R-NCO#R-N = C = N-R+CO 2 Lists of o-substituted aromatic isocyanates and lists of catalysts are given. The isocyanate is preferably treated with 0À01 to 10% of catalyst. Specifications 686,639 and 867,006 also are referred to.