| 摘要 |
PURPOSE:To obtain an image density-enhancing effect matching or exceeding the effect obtained in the case of using fine silica particles higher in cost and oil absorptivity even in the case of using fine silica particles lower in cost by using a 2-component type diazo copying material having a precoat layer contg. fine silica particles having specified characteristics. CONSTITUTION:A precoat layer formed on a support is composed essentially of a binder and fine silica particles having an oil absorptivity of 200-280ml/100g, an average particle diameter of 1-5mum, and a proportion of 2-4mum diameter particles amounting to 70-95% of the total particles. A photosensitive layer composed essentially of a diazo compd. and a coupler is formed on the precoat layer. As the binder used together with the fine silica particles, the following resins generally used in the field of diazo copying are used: Polyvinyl acetate, polyacrylate, polystyrene, PVC, styrene-butadiene copolymer, styrene-acrylic copolymer, PVA, etc. |
