Polyolefin Foam Compression Set Resistance via Activator Ratio
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Solution Overview
Problem
Polyolefin foams used in footwear applications lack superior compression set resistance compared to poly(ethylene/vinyl acetate) foams, which affects the durability and performance of footwear products.
Innovation Solution
A foamable composition comprising an olefin copolymer, an unneutralized carboxylated olefin copolymer, a crosslinking agent, a blowing agent, and an activator, with a weight ratio of the activator to the unneutralized carboxylated olefin copolymer greater than 0.3, is used to manufacture foams with improved compression set resistance and compressive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyolefin foams are used, then flexibility and cushioning are achieved, but compression set resistance is insufficient compared to poly(ethylene/vinyl acetate) foams
Solution Approach 1:
The patent modifies the chemical composition parameters of polyolefin foams by incorporating carboxylated olefin copolymer and specific crosslinking agents, changing the material's fundamental properties to achieve both flexibility and improved compression set resistance
Solution Approach 2:
The invention creates a composite foam system combining polyolefin base material with carboxylated olefin copolymer additives and crosslinking agents, achieving properties that neither component alone could provide, particularly the balance of flexibility and compression resistance
2Strength
If crosslinking agents and activators are added to improve compression set resistance, then foam density and composition complexity increase
Solution Approach 1:
The patent optimizes the weight ratio parameter of activator to unneutralized carboxylated olefin copolymer (greater than 0.3), which controls the crosslinking reaction efficiency and achieves desired compression set resistance without excessive additive quantities
Solution Approach 2:
The carboxylated olefin copolymer acts as an intermediary substance that facilitates crosslinking between polyolefin chains, enabling improved compression set resistance while maintaining relative simplicity in the overall formulation compared to direct crosslinking approaches
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 resulting foams exhibit enhanced compression set resistance and compressive strength, leading to improved durability and performance in footwear applications, with densities less than or equal to 0.23 g/cc, suitable for shoe midsoles and other industrial uses.
Implementation Method 1
heating the foamable composition to activate the blowing agent and crosslinking agent to form a crosslinked foam
Implementation Method 2
heating the foamable composition to activate the blowing agent and crosslinking agent to form a crosslinked foam
Data Source
AI summary
Disclosed herein is a foamable composition comprising an olefin copolymer that comprises ethylene and an α-olefin; an unneutralized carboxylated olefin copolymer; a crosslinking agent; a blowing agent; and an activator; where a weight ratio of the activator to the unneutralized carboxylated olefin copolymer is greater than 0.3. Disclosed herein too is a method of manufacturing a foamable composition comprising blending together an olefin copolymer that comprises ethylene and an α-olefin; an unneutralized carboxylated olefin copolymer; a crosslinking agent; a blowing agent; and an activator to form the foamable composition; where a weight ratio of the activator to the unneutralized carboxylated olefin copolymer is greater than 0.3; heating the foamable composition to activate the blowing agent to form a foam; and crosslinking the foam.