Foamed Composition Crack Prevention via Plasticizer
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Solution Overview
Problem
Existing foamed compositions, particularly low-density foams, tend to develop cracks due to overstretching of cell walls, leading to rupture and the formation of visible bubbles that persist over time.
Innovation Solution
A foamed composition comprising a thermoplastic copolyester elastomer in the range of 70 to 99 wt% combined with a plasticizer in the range of 1 to 30 wt%, where the thermoplastic copolyester elastomer includes hard segments from PBT or PET and soft segments from polybutylene adipate, poly(ethylene oxide), polypropylene oxide, or polytetramethylene oxide, along with a suitable plasticizer like Triphenyl phosphate, effectively reduces crack formation, allowing for the production of low-density, crack-free foams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If low density foams are produced, then weight is reduced, but cracks form due to overstretching of cell walls
Solution Approach 1:
The patent changes the chemical composition parameters of the foam material by incorporating specific plasticizers (phthalates, citrates, adipates, phosphates, or carboxylic acid esters) in controlled amounts (1-30 wt%). This compositional parameter change modifies the cell wall properties to prevent overstretching and rupture during foam expansion, enabling low-density foams (0.1-0.5 g/cm³) to maintain structural integrity without crack formation.
Solution Approach 2:
The patent creates a composite material system combining the base foam material with specific plasticizer additives. This composite approach allows the plasticizer to modify the cell wall characteristics and prevent crack formation while maintaining the low-density structure, resolving the contradiction between weight reduction and crack prevention.
2Reliability
If plasticizer is added to reduce crack formation, then foam integrity is improved, but composition complexity increases
Solution Approach 1:
The patent manages composition complexity by precisely controlling the plasticizer content within specific ranges (1-30 wt%, preferably 5-25 wt%). This parameter control ensures adequate crack prevention while avoiding excessive plasticizer that would overly complicate the composition. The patent also specifies particular chemical classes of plasticizers, providing guidance for practical implementation without requiring complex multi-component systems.
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 combination of thermoplastic copolyester elastomer and plasticizer results in foams with significantly reduced crack formation, enabling the creation of very low-density foams that are attractive for applications requiring lightweight materials, such as sports shoes, with densities between 0.1 and 0.5 g/cm³.
Implementation Method 1
providing a physical blowing agent under pressure to the composition while maintaining the pressure; releasing the pressure thereby forming the foamed composition
Implementation Method 2
bringing the composition to a foaming temperature of between (Tm-100)°C and Tm, in which Tm is the melting temperature of the hard segment
Data Source
Figure 1~2
AI summary
The invention relates to a foamed composition comprising a thermoplastic copolyester elastomer in an amount of between 70 to 99 wt% and a plasticizer in an amount of between 1 to 30 wt% based on the total amount of the composition and articles comprising the foamed composition, as well as a process for preparing such foamed composition.