CEN/TC 249/SC 1/WG 12 - Cellulose acetate plastics

This method is intended for cellulose acetate having an acetic acid yield of 54 % ± 2.5 %. It may also be applicable to other transparent plastics which are not strongly coloured and which can be moulded under the specified conditions. Two measurements of absorption, one at the red end and one at the blue end of the visible spectrum, are sufficient to characterize the absorption of light by the material. Describes the preparation of the material, two methods for the incorporation of plasticizers and die moulding of the test specimen. For the determination of the initial optical density, specimens given the smallest practicable amount of heating are used. The optical density at 25 mm thickness is calculated as the initial light absorption. The light absorption after further heating is obtained by similar measurements on specimens prepared using a longer period of heating during moulding.

This method is suitable for cellulose acetate which does not contain additives, fillers, etc. which may interfere with the determination of viscosity. It is suitable for cellulose acetate having an acetic acid yield above 50 %. Cellulose acetate plasticized with dimethyl phthalate is moulded under specified conditions of temperature, pressure and time. After cooling, the moulding is ground up. The viscosity ratio of the ground material from the moulding and also that of the original cellulose acetate material are determined in accordance with ISO 1157. The percentage viscosity loss is calculated from the values of viscosity before and after moulding. This second edition cancels and replaces the first edition ISO 1599:1975.