| 摘要 |
A polymer containing hydroxyl groups is prepared by subjecting a polymer of an ester of an unsaturated alcohol to the action of a hydrolysing agent whilst the polymer is in a molten state. Preferred hydrolysing agents comprise an alcohol, e.g. methanol, ethanol, propanol or butanol. An alkaline reacting catalyst may also be present, e.g. an alkali metal derivative of the alcohol used, e.g. sodium methoxide or lithium methoxide. The process may be carried out in a continuous mixing apparatus, e.g. an extruder, the hydrolysing agent being injected into the interior at a point where some heat-softening of the polymer has taken place. A blowing agent may be included and the hydrolysed polymer extruded in the form of a foam. In example, the polymers used are a copolymer of vinyl acetate and ethylene and a homopolymer of vinyl acetate. Tetrabutyl ammonium-hydroxide is used as catalyst in Example 2. |
