| 摘要 |
<p>A process for forming a phenol formaldehyde resin, the process comprising the steps of: (i) reacting phenol with an excess of a formaldehyde material in the presence of an acid or base catalyst until water separates from the reactants as an immiscible layer; (ii) adding a mixture comprising an excess of a polyhydric alcohol and an aromatic dicarboxylic or tricarboxylic acid, salt or anhydride thereof to the phenol and formaldehyde reaction mixture followed by addition of an alpha hydroxy acid; (iii) adding a non-aqueous solvent, wherein at last some of said water is removed either before addition of the mixture preparated in step (ii) or after addition of the alpha hydroxy acid; (iv) preparing a solution comprising a Lewis acid, a polyhydric alcohol, an alpha hydroxy acid, a non-aqueous solvent, an aromatic sulphonic acid and sulphuric or hydrochloric acid; (v) adding the solution formed in step (iv) to the mixture formed in step (ii) and allowing the mixture to cure.</p> |
