Laminated Foam Sheet Antistatic Agent Segmentation

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Solution Overview

Problem

Conventional antistatic foam sheets used for packaging electronic devices and glasses face issues with static electricity and surface staining due to bleeding of surfactant-type antistatic agents, which are not effectively addressed by existing laminated foam sheets containing polymeric antistatic agents, as low molecular weight components still transfer to contacted surfaces.

Innovation Solution

A laminated foam sheet with a multi-layer structure comprising a polyethylene-based foam layer and outer layers, where the intermediate layer contains a polymeric antistatic agent, while the outermost surface layer is free of the agent, ensuring excellent antistatic properties and preventing transference of low molecular weight components through coextrusion lamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a surfactant-type antistatic agent is used in a foam sheet, then antistatic property is improved, but the agent bleeds out and causes surface staining

Engineering Contradiction:

Improveantistatic propertyVSAvoidsurface staining

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the foam sheet into multiple layers: a foam layer containing the antistatic agent and an outer layer free of the agent. This segmentation prevents the antistatic agent from contacting the article surface directly, eliminating staining while maintaining antistatic functionality through the foam layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different properties to different parts of the foam sheet: the foam layer has antistatic properties (low surface resistivity) while the outer layer has staining-prevention properties (free of antistatic agents). This local differentiation resolves the contradiction between antistatic performance and surface cleanliness

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If a polymeric antistatic agent is used in laminated foam sheets, then surface staining is prevented, but low molecular weight components still transfer to contacted surfaces

Engineering Contradiction:

Improvesurface staining preventionVSAvoidtransference of low molecular weight components

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the antistatic agent from the outer layer composition entirely, placing it only in the foam layer. This extraction eliminates the source of low molecular weight component transfer to articles while the foam layer's antistatic properties are maintained through proper formulation and layer design

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If the outer layer is made thin to maintain cushioning property, then flexibility is improved, but transference prevention property deteriorates

Engineering Contradiction:

Improveflexibility and cushioningVSAvoidtransference prevention property

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite structure where the outer layer (free of antistatic agents) and foam layer (containing antistatic agents) work together. The outer layer provides flexibility and cushioning even at thin dimensions, while the foam layer provides the barrier function against transference, achieving both goals through material composition rather than thickness alone

Inventive Principle:

Principle #40Composite materials

Data Source

PatentEP3702145B1Laminated foam sheet

Publication Date: 2022.10.19 JSP CORP

Figure 1

AI summary

A laminated foam sheet having a polyethylene resin foam layer and an outer layer laminated on each side of the foam layer, each outer layer being composed of an outermost surface polyethylene resin layer and an intermediate polyethylene resin layer which is positioned between the outermost surface layer and the foam layer and which contains a specific amount of a polymeric antistatic agent relative to the weight of the intermediate layer and to the basis weight of each of the intermediate layer and outermost surface layer.