Polyolefin Foam Sheet Thermal Insulation and Flexibility

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Solution Overview

Problem

Conventional polyolefin resin foam sheets face challenges in achieving high thermal insulation performance while maintaining flexibility and impact-absorbing properties, especially as electronic equipment thickness reduces and heat generation increases in IT applications.

Innovation Solution

A polyolefin resin foam sheet with a 50% compressive strength of 120 kPa or less, elongation percentages of 400% or less in the machine direction and 200% or less in the transverse direction, thermal conductivity of 0.050 W/(m·K) or less, and a crosslinked structure with a degree of crosslinking between 30% to 60% by mass, which enhances flexibility and thermal insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the thickness of polyolefin resin foam sheet is reduced to meet thin electronic equipment requirements, then the foam sheet can be used in thin devices, but thermal insulation performance becomes insufficient

Engineering Contradiction:
ImprovethicknessVSAvoidthermal insulation performance
Core Design Contradiction:
Length of moving objectVSTemperature

Solution Approach 1:

The patent utilizes a foam structure with numerous closed cells containing gas, creating a porous material that provides thermal insulation. The gas-filled cells act as thermal barriers, maintaining high insulation performance even in thin configurations by maximizing the insulating air/gas content within the limited thickness.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent optimizes specific parameters including setting 50% compressive strength at 120 kPa or less, elongation at break in TD direction at 200% or less, and thermal conductivity at 0.050 W/(m·K) or less. These parameter changes enable the foam to achieve both thin profile and high thermal insulation performance simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the flexibility of polyolefin resin foam sheet is increased to improve impact-absorbing properties, then impact resistance is enhanced, but thermal insulation performance deteriorates

Engineering Contradiction:
Improveimpact-absorbing propertiesVSAvoidthermal insulation performance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent identifies specific parameter ranges that balance flexibility and thermal insulation: 50% compressive strength of 120 kPa or less for flexibility, elongation at break of 200% or less in TD direction, and thermal conductivity of 0.050 W/(m·K) or less. By controlling these parameters within defined ranges, the foam achieves both high impact absorption and maintained thermal insulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining polyolefin resin matrix with dispersed closed-cell foam structure. This composite architecture provides both the flexibility needed for impact absorption through cell deformation and the thermal insulation through gas-filled cell barriers.

Inventive Principle:
Principle #40Composite materials

3Strength

If the crosslinking degree is increased to improve mechanical strength, then structural integrity is enhanced, but flexibility and impact-absorbing properties deteriorate

Engineering Contradiction:
Improvemechanical strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent controls the degree of crosslinking within an optimized range to achieve the desired balance. By adjusting crosslinking density and controlling the 50% compressive strength at 120 kPa or less, the foam maintains both structural integrity from crosslinking and flexibility for impact absorption.

Inventive Principle:
Principle #35Parameter changes

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 improves thermal insulation properties while maintaining flexibility and impact-absorbing capabilities, allowing the foam sheet to be effectively used in thin electronic equipment without compromising mechanical strength or ease of installation in narrow gaps.

Implementation Method 1

a crosslinked structure with a degree of crosslinking between 30% to 60% by mass, which enhances flexibility and thermal insulation

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

thermal conductivity of 0.050 W/(m·K) or less; improved thermal insulation properties

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11352525B2Polyolefin resin foamed sheet and adhesive tape
Publication Date: 2022.06.07 SEKISUI CHEMICAL CO LTD

AI summary

The polyolefin resin foam sheet is a polyolefin resin foam sheet having a plurality of cells in an inside thereof, wherein the 50% compressive strength is 120 kPa or less; the MD elongation percentage is 400% or less; and the TD elongation percentage is 200% or less.