Crosslinked HPPE Copolymer Foam for Temperature-Stable Impact Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-pressure polyethylene (HPPE) copolymers, particularly those based on ethylene vinyl acetate (EVA), suffer from mechanical property impairments, inconsistent performance across temperature ranges, and limited foaming capability, necessitating the use of expensive additives like olefin block copolymers or thermoplastic polyurethane to improve these properties.
Innovation Solution
A foam composition comprising a copolymer of ethylene and alkyl (meth)acrylate, optionally with ethylene vinyl acetate, and additives such as chemical blowing agents and crosslinking agents, which are used to create a crosslinked foam material with improved mechanical properties and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If EVA copolymer is used as main polymer component, then low cost and good adhesion are achieved, but mechanical properties such as impact absorption are impaired
Solution Approach 1:
The patent uses a composite foam structure combining EVA copolymer with a cellular foam material (such as polyurethane foam, polyethylene foam, or other foamed plastics) to create a multi-layered material system. This composite approach allows the EVA layer to provide adhesion and cost-effectiveness while the foam core provides impact absorption and mechanical properties, thus resolving the contradiction between low cost/good adhesion and improved impact absorption
2Ease of manufacture
If EVA copolymer is used, then low cost is achieved, but performance consistency across temperature ranges deteriorates
Solution Approach 1:
The patent employs a composite structure where EVA copolymer is combined with foam materials that have complementary thermal properties. The foam core material is selected to provide dimensional stability and consistent mechanical properties across temperature ranges, while the EVA outer layer maintains adhesion and cost-effectiveness. This composite approach allows the system to maintain reliable performance across temperatures from -40°C to 80°C despite the EVA component's temperature sensitivity
3Quantity of substance
If high amounts of blowing agents are added to EVA copolymer, then foam density is reduced, but decomposition and acid generation at processing temperatures increases
Solution Approach 1:
The patent extracts the foaming function from the EVA copolymer formulation by using a separate pre-formed foam material as the core component. This eliminates the need to add large amounts of blowing agents to the EVA copolymer itself, thereby avoiding decomposition and acid generation during processing. The foam structure is obtained by physically incorporating a pre-manufactured foam material rather than chemically foaming the polymer blend
Solution Approach 2:
The patent introduces a pre-formed foam material as an intermediary component that serves as the core structure. This foam material acts as a mediator between the EVA copolymer and the final foam product, providing the desired low density and cellular structure without requiring the EVA copolymer to undergo extensive chemical foaming that would cause decomposition and acid generation
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 new foam material exhibits enhanced mechanical properties, consistent performance across a broad temperature range, and reduced foam density requirements, making it suitable for applications like footwear without the need for expensive additives.
Implementation Method 1
chemical blowing agents and crosslinking agents, which are used to create a crosslinked foam material
Implementation Method 2
crosslinking agents, which are used to create a crosslinked foam material
Data Source
AI summary
The present invention relates to a foam composition comprising a) a resin composition comprising a1) 25 to 100 phr of a copolymer of ethylene and alkyl (meth)acrylate, wherein the alkyl (meth)acrylate is selected from the group consisting of methyl (meth)acrylate and butyl (meth)acrylate; and a2) 0 to 75 phr of a copolymer of ethylene and vinyl acetate; and 1 to 25 phr of foam composition additives. The present invention also relates to a foam material obtainable from the foam composition, and a method of making an article comprising the foam material, as well as to a footwear article comprising the foam material.