| 摘要 |
The mixture of phenol and formaldehyde was condensed by at least two steps in the presence of alkali catalyst to give intermediate. The intermediate was cooled and pH was adjusted to 3.0-4.0 by adding enough acid and then condensed to give title phenol resin.Thus, the mixture of formaldehyde and phenol(mol. wt. ratio = 1.4:1) and NaOH (2 wt.% of phenol) was condensed at 70-100≦̸C for 1 hr.
|
