PPE-PS Resin Foamed Blow-Molding Process
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Solution Overview
Problem
It is difficult to produce hollow foamed blow-molded articles using a thermoplastic resin composition containing a mixed resin of polyphenylene ether resin and polystyrene resin via the foaming blow-molding method, which has not been practically industrialized due to challenges in achieving the required melt viscosity and glass transition temperature for effective foaming and blow molding.
Innovation Solution
A method involving extruding a foamable molten resin composition containing a mixed resin of polyphenylene ether resin and polystyrene resin with a specific melt viscosity and glass transition temperature, combined with a physical blowing agent, to form a foamed parison that can be blow molded into a hollow, highly expanded, and lightweight article with enhanced heat resistance and flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermoplastic resin composition containing mixed resin of polyphenylene ether resin and polystyrene resin is used for foaming blow-molding, then the heat resistance and mechanical strength balance are improved, but it is difficult to achieve the required melt viscosity and glass transition temperature for effective foaming and blow molding
Solution Approach 1:
The invention changes the chemical composition parameters of the thermoplastic resin by incorporating specific flame retardant compounds (phosphorus-type flame retardants with melting points of 100°C or lower) into the mixed resin system. This parameter change modifies the resin's thermal properties, achieving a glass transition temperature of 110°C or higher while maintaining manufacturability through foaming blow-molding processes.
Solution Approach 2:
The invention creates a composite material system by combining polyphenylene ether resin, polystyrene resin, and phosphorus-type flame retardants in specific ratios. This composite approach allows the material to simultaneously achieve high heat resistance (Tg ≥ 110°C), appropriate melt viscosity for foaming, and good mechanical strength balance, resolving the contradiction between thermal performance and processability.
2Manufacturing precision
If the melt viscosity is increased to maintain the softened state during blow molding, then the hollow molded article can be formed with good shape retention, but the foaming expansion ratio and apparent density are reduced
Solution Approach 1:
The invention utilizes phase transition characteristics of the phosphorus-type flame retardants (with melting points ≤100°C) during the blow molding process. These compounds undergo solid-liquid phase transitions at processing temperatures, temporarily reducing melt viscosity to enable foaming expansion, then solidify upon cooling to maintain shape retention, thus resolving the contradiction between expansion ratio and shape stability.
Solution Approach 2:
The invention exploits periodic changes in material properties during processing: the flame retardants periodically transition between solid and liquid states during heating and cooling cycles, creating windows of low viscosity for foaming followed by high viscosity for shape fixation. This periodic action enables both high expansion ratio and good shape retention.
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 enables the production of hollow foamed blow-molded articles with low apparent density and high heat resistance, suitable for electric and electronic parts, and those requiring flame retardancy, such as aircraft and railway vehicle components, by maintaining the softened state of the foamed parison and controlling the melt viscosity and glass transition temperature.
Implementation Method 1
extruding a foamable molten resin composition obtained by kneading a thermoplastic resin composition containing a mixed resin of a polyphenylene ether resin and a polystyrene resin, and a physical blowing agent
Implementation Method 2
A method for producing a thermoplastic resin foamed blow-molded article, comprising: extruding a foamable molten resin composition obtained by kneading a thermoplastic resin composition
Data Source
AI summary
Provided is a hollow foamed blow-molded article having a high heat resistance, employing a thermoplastic resin composition containing a mixed resin of a polyphenylene ether resin and a polystyrene resin, as a base resin. The foamed blow-molded article, may be produced by extruding a foamable molten resin composition obtained by kneading the thermoplastic resin composition and a blowing agent to form a foamed parison, and blow molding the foamed parison. A glass transition temperature of the thermoplastic resin composition is 110° C. or higher. A melt viscosity of the thermoplastic resin composition at a temperature of the glass transition temperature+80° C. and at a shear rate of 100/sec is 3000 to 9500 Pa·s. The physical blowing agent is a blowing agent containing a hydrocarbon compound having 3-5 carbon atoms. A blending amount of the physical blowing agent is 0.4 to 1 mol per kg of the thermoplastic resin composition.