Polyethylene Foam Regrind Extrusion to Prevent Hopper Clogging
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Solution Overview
Problem
The clogging of the hopper in the extruder during the mass production of polyethylene-based foamed molded products with high expansion ratios leads to low production efficiency, particularly when using pulverized material.
Innovation Solution
The method involves using a pulverizer with a screen mesh opening diameter of 8.0 mm or less and configuring the head with a die core and die shell to form a foamed parison, where the angle between the die core and die shell flow path forming surfaces is 3.0 degrees or more, to prevent clogging and form a foamed molded body with an expansion ratio of 2.0 or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulverized material is used in mass production of polyethylene-based foamed molded products with high expansion ratio, then production efficiency can be improved through material reuse, but the pulverized material frequently clogs the hopper of the extruder
Solution Approach 1:
The patent changes the parameter of opening diameter in the screen mesh of the pulverizer from conventional larger sizes to 8.0 mm or less. This parameter change allows the pulverized material to be discharged more effectively and prevents clogging in the extruder hopper, while still maintaining the benefits of using recycled pulverized material in mass production.
2Reliability
If the opening diameter of the screen mesh is reduced to suppress hopper clogging, then material flow is improved, but the pulverization efficiency may be affected
Solution Approach 1:
The patent optimizes the opening diameter parameter to 8.0 mm or less, which is small enough to prevent hopper clogging but large enough to maintain acceptable pulverization efficiency. This parameter optimization balances the conflicting requirements of clogging suppression and production efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses hopper clogging and prevents striped unevenness on the inner surface of the molded body, enhancing mass production efficiency and product quality.
Implementation Method 1
raw material resin and a foaming agent are melt-kneaded in an extruder to obtain a foaming agent-containing resin in a molten state
Implementation Method 2
the obtained foaming agent-containing resin is extruded from a head to form a foamed parison
Implementation Method 3
the foamed parison is molded using a mold to form a foamed molded body
Implementation Method 4
The removed portion is usually pulverized in a pulverizer to become a pulverized material
Data Source
AI summary
Provided is a manufacturing method for a foamed molded body that can improve the mass production efficiency of polyethylene-based foamed molded products with high expansion ratio. The method comprises a feeding step for feeding raw material resin into an internal space of a cylinder of an extruder through a hopper; wherein the raw material resin comprises 50 mass % or more of a polyethylene-based resin; the raw material resin comprises a pulverized material produced by pulverizing a foamed body using a pulverizer; the foamed body is composed of a resin comprising 50 mass % or more of a polyethylene-based resin and has an expansion ratio of 2.0 or more; the pulverizer is configured to discharge the pulverized material from the pulverizer through an opening provided in a screen mesh; and a diameter of the opening is 8.0 mm or less.