Abstract

An injection apparatus including a plasticizing unit (2) that plasticizes a raw material resin and an injection unit (3) that injects a plasticized molten resin. The plasticizing unit includes a heating cylinder (20) having a foaming gas injection valve and a screw (21) provided inside the heating cylinder. The rotation and advance and retreat movements of the screw are controlled such that a raw material resin is plasticized by the screw and a foaming gas injected from a foaming gas injection valve is dissolved in the plasticized molten resin. After the screw retreats to a prescribed position according as the molten resin accumulates in the front end side of the heating cylinder by the screw that is rotating, the screw advances with rotating to cause the molten resin which has been accumulated in the front end side of the heating cylinder to be transferred to the injection unit.

IPC Classes  ?

• B29C 44/34 - Component parts, details or accessoriesAuxiliary operations
• B29C 45/50 - Axially movable screw
• B29C 45/02 - Transfer moulding, i.e. transferring the required volume of moulding material by a plunger from a "shot" cavity into a mould cavity
• B29C 45/17 - Component parts, details or accessoriesAuxiliary operations
• B29C 44/42 - Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum
• B29C 45/54 - Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston and plasticising screw
• B29C 45/00 - Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mouldApparatus therefor
• B29C 45/53 - Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston
• B29K 67/00 - Use of polyesters as moulding material
• B29K 105/04 - Condition, form or state of moulded material cellular or porous
• B29L 31/00 - Other particular articles

Abstract

A plasticizing process in which a molten resin that has been plasticized and dissolved in a foaming gas is sent to the front end side of a heating cylinder (20) by means of a screw (21) that rotates in a heating cylinder (20), and the screw (21) retreats according as the molten resin accumulates in the front end side of the heating cylinder (20); a transfer process in which the screw (21) is advanced with rotating and transfers the molten resin accumulated in the front end side of the heating cylinder (20) from a plasticizing unit (2) to an injection unit (3), and an injection process in which the molten resin is injected from the injection unit (3) are conducted and repeated to produce a foamable injection molded product.

IPC Classes  ?

• B29C 44/34 - Component parts, details or accessoriesAuxiliary operations
• B29C 45/50 - Axially movable screw
• B29C 45/02 - Transfer moulding, i.e. transferring the required volume of moulding material by a plunger from a "shot" cavity into a mould cavity
• B29C 45/54 - Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston and plasticising screw
• B29C 45/17 - Component parts, details or accessoriesAuxiliary operations
• B29C 44/42 - Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum
• B29C 45/00 - Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mouldApparatus therefor
• B29C 45/53 - Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston
• B29K 67/00 - Use of polyesters as moulding material
• B29K 105/04 - Condition, form or state of moulded material cellular or porous
• B29L 31/00 - Other particular articles

Abstract

Foamable injection moldings are manufactured by performing a plasticizing process, a transfer process, and an injection process, and repeating said processes. In the plasticizing process, a plasticized molten resin impregnated with a foaming gas is fed to the tip of a heating cylinder (20) by a screw (21) rotating inside the heating cylinder (20) and the screw (21) moves backward as the molten resin accumulates in the tip of the heating cylinder (20). In the transfer process, the screw (21) moves forward while rotating to deliver the molten resin accumulated in the tip of the heating cylinder (20) from the plasticizing unit (2) to an injection unit (3). The injection process injects the molten resin from the injection unit (3). As a result, when injection-molding a foamable injection molding impregnated with foaming gas, plasticization of the material resin during the forming cycle and impregnation of the foaming gas into the plasticized molten resin are improved and productivity can be improved.

IPC Classes  ?

• B29C 45/00 - Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mouldApparatus therefor
• B29C 45/54 - Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston and plasticising screw
• B29K 105/04 - Condition, form or state of moulded material cellular or porous