Thermoplastic Polyester Elastomer Foam Molding
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Solution Overview
Problem
Thermoplastic polyester elastomer foams face challenges in achieving lightweight, high rebound resilience, and uniform density due to low melt viscosity and gelling issues during foam molding, with existing methods resulting in high-density products and environmental concerns from urethane foams.
Innovation Solution
A thermoplastic polyester elastomer foam molded product with a specific hard and soft segment ratio and controlled foamed cell size, produced through injection molding with a cavity expansion process using a chemical foaming agent or inert gas in a supercritical state, achieving a lightweight, high rebound resilience, and uniform cell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermoplastic polyester elastomer prepared by melt polycondensation is used for foam molding, then the resin has excellent rubber properties and flexibility, but the low melt viscosity prevents sufficient moldability and causes gelling issues during foam molding
Solution Approach 1:
The patent changes the molecular weight parameter of the thermoplastic polyester elastomer to 20,000-100,000, which optimizes the balance between melt viscosity and rubber properties. This parameter adjustment enables the resin to maintain sufficient viscosity for foam molding while preserving excellent elasticity recovery and flexibility, resolving the contradiction between moldability and rubber properties
Solution Approach 2:
The patent uses a composite approach by combining thermoplastic polyester elastomer with specific additives including silicon oxide (0.1-5 parts by mass) and titanium oxide (0.1-5 parts by mass). This composite formulation enhances the resin's viscosity stability during foam molding, preventing gelling while maintaining excellent rubber properties and enabling successful foam molding
2Ease of manufacture
If existing foam molding methods are used to increase density, then moldability improves, but the resulting foam molded product has high density which contradicts the lightweight requirement
Solution Approach 1:
The patent changes the molecular weight parameter to an optimized range (20,000-100,000) and controls the soft segment content (30-70 parts by mass per 100 parts hard segment), which provides sufficient melt viscosity for moldability while enabling the production of lightweight foam with density of 0.01-0.35 g/cm³, thus resolving the contradiction between moldability and lightweight requirements
3Ease of manufacture
If cross-linking agents or thickeners are added to increase melt viscosity, then the resin becomes suitable for foam molding, but the preparation reaction is not sufficiently controlled and the resulting polyester elastomer greatly depends on retention time
Solution Approach 1:
The patent replaces complex cross-linking agents and thickeners with a simpler approach using readily available fillers (silicon oxide and titanium oxide) that provide stable viscosity enhancement without complex reaction mechanisms. This eliminates the retention time dependency and reaction control issues, providing reliable and stable melt viscosity for foam molding
Solution Approach 2:
The patent creates a composite system incorporating silicon oxide (0.1-5 parts by mass) and titanium oxide (0.1-5 parts by mass) with the thermoplastic polyester elastomer. This composite formulation provides stable viscosity enhancement without the side effects of cross-linking agents, ensuring consistent foam molding results independent of retention time variations
4Reliability
If urethane foamed products are used to achieve high rebound resilience, then the rebound resilience reaches 60% or more, but the product generates cyan gas upon burning causing environmental pollution
Solution Approach 1:
The patent converts the potential harm of using conventional foaming agents into a benefit by selecting carbon dioxide or nitrogen as alternative foaming agents. These agents provide the necessary foaming action to achieve high rebound resilience (60-90%) while being environmentally benign and not generating toxic cyan gas during combustion, thus resolving the contradiction between performance and environmental safety
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 solution results in a lightweight, high-rebound resilience foam with uniform cell structure, high heat and water resistance, and stable molding, suitable for applications requiring high reliability.
Implementation Method 1
injected together with a chemical foaming agent and/or inert gas in a supercritical state
Implementation Method 2
a foam molded product of thermoplastic polyester elastomer resin
Data Source
AI summary
According to the present invention, there is provided a foam molded product of thermoplastic polyester elastomer resin which exhibits light weight and excellent rebound resilience. The foam molded product is characterized in that, the foam molded product has a foamed layer consisting of a resin phase and an isolated foamed cell.