PURPOSE: To obtain an injection cylinder which possesses the easily degradable property under the natural environment and excellent transparency by forming the injection cylinder from the thermoplastic polymer composition which contains polylactic acid, or copolymer of lactic acid and other hydroxycarboxylic acid, as a main constituent.
CONSTITUTION: An injection cylinder is made of the composition containing polyactic acid or a copolymer of lactic acid and other hydroxycarboxyluc acid, as a main component. As the polymer used in this case, the polylactica acid- based polymer is used as a main constituent, and as other hydroxycarboxylic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4- hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, etc., are used. In order to obtain the injection cylinder by using the thermoplastic polymer composition, the composition is melted, injected and filled into the cavity of a metal mold which is in a previously closed state, and a shaped article is formed through solidification or hardening.
AJIOKA MASANOBU
YAMAGUCHI TERUHIRO
SUZUKI KAZUHIKO
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