EXTRUSION MOLDING DEVICE FOR MULTI-LAYER PARISON

• Main Authors: FUKUHARA KEIJI, OSUGI MASAKATSU, HARA MASAO, HISAMITSU HIROTOMO
• Format: Patent
• Language: English
• Published: 07.05.1991
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; MAKING GRANULES OR PREFORMS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PURPOSE:To form a multi-layer parison having a resin layer without unevenness all over, even if resin of comparatively high moisture absorbing properties is used, by setting variable extrusion pressure of an extruder based on the water absorbing rate of the resin sensed by a sensing means. CONSTITUTION:An extrusion molding device 10 is provided with a water absorbing rate sensor 110 for measuring the water absorbing rate of nylon as an auxiliary material in a material feeding system and an auxiliary material/ bonding agent control circuit 101 constituted for setting variably the target extrusion pressure of a second extruder 12 based on the water absorbing rate of nylon sensed by the water absorbing sensor 110. When the water absorbing rate of nylon is high and the melting viscosity of molten nylon in an accumulator 20 is low, the target extrusion pressure of the second extruder 12 is set low to control the action of a second electromagnetic proportional type pressure servo valve 107 and control the nylon not to be extruded in excess. On the other hand, when the water absorbing rate of nylon is low, the target extrusion pressure of the second extruder 12 is set high to control the action of the second electromagnetic proportional type pressure servo valve 107 to prevent the shortage of extrusion quantity of nylon.