| 摘要 |
A pre-cure resistant liquid phenol-formaldehyde resin binder composition is disclosed having low viscosity and low surface tension and comprising a highly condensed and cross-linkable phenol-formaldehyde resin of relatively high average molecular weight e.g. in the range of from 2000 to 6000, and a viscosity of 100 to 450 cps at 25 DEG C and a non- resinous methylolated phenol condensate having an average molecular weight of 200-300. The composition is formed by reacting phenol and formaldehyde with an alkaline catalyst at above 80 DEG C, reducing the temperature of the resulting resin to about 60 DEG C, adding further phenol, formaldehyde and alkaline catalyst and reacting the resin further at 45-70 DEG C, then chilling to below room temperature. Uses:- as a binder in waferboard manufacture. |
