| 摘要 |
<p>PURPOSE: To recover reusable chips easily and safely at a low cost by treating a polyester photographic base with an alkaline aqueous solution containing sodium hydroxide and/or potassium hydroxide. CONSTITUTION: A polyester photographic base having at least one undercoating layer is treated with an alkaline aqueous solution containing sodium hydroxide and/or potassium hydroxide. The temperature of the treating liquid is set to 70-100 deg.C. When the temperature is lower than this range, the treatment requires too much time. When the temperature is 100 deg.C or above, the heating energy consumption becomes excessive, and the cost is increased. The alkali concentration of the treating liquid is preferably set to 0.2-10. When the concentration is lower than this range, the raw material of the undercoating back emulsion layer is hardly removed. When the concentration is higher than this range, the deterioration of quality, e.g. the reduction of the molecular weight of polyester, occurs. When a surface active agent is added to the treating liquid, impurities of obtained chips can be prevented.</p> |
