| 摘要 |
1,192,859. Isocyanates. TAKEDA YAKUHIN KOGYO K.K. 23 Dec., 1968 [28 Dec., 1967], No. 61137/68. Heading C2C. Organic isocyanates are stabilized against polymerization and coloration by adding a small proportion of (1) sulphur or hydrogen sulphide or (2) a compound containing the grouping A-NH-B, in which A denotes -CO-, -CS-, -SO 2 -, -NO 2 or -CN and B denotes -CO- or -CS- or (3) a compound of any of the formulµ R<SP>1</SP>CXNHR<SP>3</SP>, R<SP>2</SP>(CONHR<SP>3</SP>) 2 , (CONHR<SP>3</SP>) 2 or R<SP>4</SP>SO 2 NHR<SP>3</SP>, in which X denotes oxygen or sulphur, R<SP>1</SP>, R<SP>3</SP> and R<SP>4</SP> denote hydrogen atoms or alkyl or aryl groups which may be substituted by halogen atoms or nitro, cyano, alkyl or alkoxy groups and R<SP>2</SP> denotes a divalent hydrocarbon residue, such as an alkylene or arylene residue. Many compounds falling within categories (2) and (3) are specified, as also are a number of mono-, di- or tri-isocyanates to which the invention may be applied. Comparative examples are given of the treatment of dimethylbenzene - #,#<SP>1</SP> - diisocyanate and 4,41- diphenylmethane diisocyanate. |
