| 摘要 |
An environmentally friendly autoxidisable alkyd coating composition (especially a paint) in which some of the film-forming material has been co-reacted with polyamide or a polyamine/polyisocyanate combination and which prior to the co-reaction has an Mz of at least 30,000, a viscosity of less than 34 stokes at 25 DEG C measured as a 99wt% solution in xylene, a non-uniform molecular weight distribution which peaks in the range 1,500 to 3,500 which range also contains at least 25wt% of the material and preferably at least 2wt% of the material has a molecular weight above 100,000. This combination of characteristics enables the composition to contain less than 15wt% organic solvent if desired whilst retaining properties similar to conventional alkyd compositions. Preferred film-forming material contains esters of polycarboxylic acids containing at least three carboxylic acid groups in which the esterifying groups are a) alkyd polymer moieties, b) dipentaerythrityl and/or pentaerthrityl dicarboxylate moieties and optionally c) pentaerythrityl moieties. <IMAGE> |
