Die head for forming multilayered resin and extruder having the same

Abstract

A die head has a plunger and metering chambers. Uniform amounts of molten resins are supplied to a die head of an extruder, uniform amounts of the molten resins are discharged from the die head, and the timings of the discharge are uniformly controlled. A main-layer forming flow passage and a core-layer flow passage are formed in a die head. Metering chambers are provided in the main-layer forming flow passage and the core-layer flow passage, and molten resins are forced from the upstream of the flow passages into the main-layer forming passage and the core-layer flow passage by molten resin pumping force. Plungers retracted by the molten resin pumping force and discharging the metered molten resins to the downstream of the flow passage are installed in the metering chambers. The amounts of discharge of the molten resins by the plungers and the timings of the discharge are controlled by a control section for controlling the plunger.

Description

technical field [0001] The present invention relates to a die for forming a multi-layered resin and an extrusion molding machine having the same, wherein the die covers a main layer of molten resin flowing out of a main layer forming flow path from a core layer forming flow path The surrounding part of the molten resin core layer forms a multi-layer resin. Background technique [0002] As is well known to those skilled in the art, a composite molten resin material comprising an outer molten resin layer (main layer) and at least one inner molten resin layer (core layer) wrapped in the outer molten resin layer is often used as a material for forming a prefabricated Synthetic resin material for articles (often referred to as "preforms") formed by cutting molten resin extruded from an extrusion molding machine into drops (blocks) followed by compression molding for Forming (usually blow molding) containers for beverages or for forming container lids or cups. As the outer molte...

AI Technical Summary

Problems solved by technology

However, in practice, even if the distance from the ejection port to the die is set equal, it is difficult to evenly distribute and supply the molten resin due to the discrete processing accuracy of the flow path and the die and due to the dispersion of temperature to die

In addition, it is usually not possible to set the lengths of the flow paths to be equal

Images