Biodegradable Resin Preform Heating for Tear-Free Blow Molding
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Solution Overview
Problem
Existing blow molding apparatuses struggle to reliably demold preforms made of biodegradable resin without tearing them off during the process, especially when manufacturing medium to large-sized containers, due to the biodegradable resin's poor moldability and high material cost, and the difficulty in setting the appropriate temperature for both demolding and blow molding without cracking or tearing.
Innovation Solution
A manufacturing method involving an injection molding process with a temperature-controlled injection molding mold set to 40°C or lower, followed by a temperature adjustment process that heats the inner and outer skin layers of the preform to the melting point or close to it, ensuring the preform can be demolded without adhering to the mold and preventing tearing during blow molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the injection molding mold temperature is set high to demold the preform at a high temperature state, then the preform can be demolded without adhering to the mold, but the preform cannot be sufficiently cooled and remains at a high temperature causing inner and outer skin layers to adhere to the mold in an adhesive manner
Solution Approach 1:
The invention changes the temperature parameter of the injection molding mold to a specific range (50-80°C) that is higher than conventional temperatures. This parameter change enables the preform to be demolded without adhesion while preventing excessive heat retention that would cause skin layer adhesion. The controlled temperature range resolves the contradiction by finding an optimal balance point.
2Temperature
If the preform is molded so as to be sufficiently cooled by the injection molding mold set to a low temperature, then the preform can be solidified, but the heat quantity required for the blow molding cannot be left in the preform
Solution Approach 1:
The invention adjusts the injection molding mold temperature to a specific range (50-80°C) that preserves sufficient heat quantity for blow molding while achieving adequate cooling of the preform. This parameter optimization ensures both requirements are met simultaneously, resolving the contradiction between cooling and heat retention.
3Device complexity
If the temperature of the preform of a biodegradable resin is adjusted at the same temperature as that of the normal resin material, then the temperature adjustment process can be simplified, but the inner and outer skin layers of the preform are cooled and solidified more than necessary causing the preform to be cracked or torn off during stretching
Solution Approach 1:
The invention changes the temperature adjustment parameters to maintain the preform temperature closer to the melting point of the biodegradable resin. This parameter adjustment prevents excessive cooling and solidification of the skin layers, thereby preventing cracking and tearing during stretching while maintaining a relatively simple temperature adjustment process.
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
The method allows for successful demolding of biodegradable resin preforms without deformation and cracking, enabling the production of biodegradable containers by maintaining the necessary heat quantity for blow molding.
Implementation Method 1
the preform cannot be sufficiently cooled in an injection molding process and remains at a high temperature
Implementation Method 2
a temperature adjustment process of adjusting a temperature of the preform (1) in a temperature adjustment mold
Data Source
AI summary
A manufacturing method for manufacturing a biodegradable resin container includes at least: an injection molding process of injection molding a preform made of a biodegradable resin in an injection molding mold; a temperature adjustment process of adjusting a temperature of the preform in a temperature adjustment mold; and a blow molding process of manufacturing a container by blow molding the preform after temperature adjustment in a blow mold, in which a temperature of the injection molding mold is set to 40° C. or lower.