| 摘要 |
<p>Cold-setting binder for casting cores and moulds, pref. prepared by mixing binder with foundry sand and acid hardener, shaping and allowing to set, contains (I) a Si-Free cold-setting synthetic resin, pref. condensate(s) of HCHO and phenol and/or urea and/or melamine, and (II) a silane R'Si(OR)3 (where R is (m)ethyl and R' is an epoxy gp-contg. organic residue), pref. (II) concn. being 0.01 - 3 (0.05 - 2) wt. % based on wt. of binder and 0.0001 - 0.1 (0.0002 - 0.06) wt.% based on wt. of article. Pref. one C atom of R' is linket to Si; R' consists only of C, H and O; is free from olefinic double bonds and from triple bonds; and contains 3-6 C. Pref. all R gps. are methyl.</p> |
