| 摘要 |
Resinous binders are formed by reacting at elevated temperatures: (a) lignin sulfonic acids or their derivatives, sulfonated lignin resins and/or other sulfonated resins with: (b) 20-120% parts by weight based on (a) of primary, secondary, tertiary and/or quaternary amines containing at least one aliphatic or alicyclic substituent having more than 6 carbon atoms. Preferably up to 55% by weight of: (c) formaldehyde is also combined, based on the weight of (b). The resin may also be modified with: (d) a phenolic, alkyl phenolic and/or epoxy resin. Binding metal foundry sands, for moulds and cores, and for producing heat resistant surface coatings on foundry moulds. Ready solubility or dispersibility in highly volatile organic solvents is proved. Setting occurs on evapn. of solvent. Adequate heat resistance and low moisture sensitivity. Moulds can be used repeatedly. |
