Laminated Foam Sheet Curl Suppression via Friction Layering
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Solution Overview
Problem
Existing laminated foam sheets lack both strength and a curl suppressing property, and existing solutions do not address these requirements effectively for applications such as food packaging containers and vehicle floor mats.
Innovation Solution
A laminated foam sheet structure comprising a foam layer with a polyolefin-based resin, a first non-foam layer with a non-cross-linked olefin-based elastomer, and a second non-foam layer with specific static friction and melting point characteristics, along with a controlled resin ratio and filler content, to achieve a non-slip surface, enhanced strength, and improved curl suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a laminated foam sheet uses a foam layer with thermoplastic resin and non-foam layers to achieve light weight and heat resistance, then the basic structural requirements are met, but the sheet exhibits curling and lacks sufficient strength
Solution Approach 1:
The invention changes the physical and chemical parameters of the resin layers, specifically controlling the melting point difference between the first and second non-foam layers to be 10°C or less, and adjusting the basis weight ratio to 0.5-2.0. These parameter optimizations reduce internal stress and prevent curling while enhancing overall sheet strength.
Solution Approach 2:
The invention uses a composite structure with three distinct layers: a foam layer (2.0-6.0mm thick with 70%+ closed cell ratio) as the core, a first non-foam layer with high friction coefficient (≥2.0) for grip, and a second non-foam layer with low friction coefficient (≤1.0) for smooth surface. This composite material approach balances strength, anti-curling, and surface properties.
2Ease of operation
If the laminated foam sheet adds non-foam layers to achieve non-slip properties, then grip property is improved, but the sheet develops curling and strength is insufficient
Solution Approach 1:
The invention applies local quality by giving each layer distinct functional characteristics: the first non-foam layer has high friction coefficient (≥2.0) specifically for grip enhancement, while the second non-foam layer has low friction coefficient (≤1.0) for curl suppression and smooth surface. This localized functional differentiation resolves the contradiction between grip and anti-curling.
Solution Approach 2:
The invention optimizes the basis weight ratio between the first and second non-foam layers to be 0.5-2.0, and controls the melting point difference to be 10°C or less. These parameter changes ensure that the high-friction layer provides grip while the low-friction layer prevents curling, achieving both grip property and curl suppression simultaneously.
3Strength
If the foam layer thickness is increased to improve strength, then structural integrity is enhanced, but the sheet becomes more prone to curling and harder to handle
Solution Approach 1:
The invention optimizes the foam layer thickness to a specific range of 2.0-6.0mm, which provides sufficient structural integrity and strength while maintaining manageable dimensions. This parameter optimization prevents excessive thickness that would cause curling and handling difficulties, while ensuring adequate strength for the application.
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 proposed laminated foam sheet structure provides a non-slip surface, excellent strength, and effective curl suppression, making it suitable for applications like vehicle floor mats and luggage trays, while maintaining handleability and thermoformability.
Implementation Method 1
the first non-foam layer has a maximum static friction coefficient determined by JIS K7125 of 2.0 or more
Implementation Method 2
the foam layer includes a polyolefin-based resin, the foam layer has a closed cell ratio of 70% or more
Implementation Method 3
a laminated foam sheet provided with a foam layer using a thermoplastic resin as a base material resin and a non-foam layer using a thermoplastic resin as a base material resin
Data Source
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AI summary
A laminated foam sheet includes a foam layer, a first non-foam layer positioned on one side of the foam layer, and a second non-foam layer positioned on another side of the foam layer, in which the foam layer includes a polyolefin-based resin, the foam layer has a thickness of 2.0 to 6.0 mm, the foam layer has a closed cell ratio of 70% or more, the first non-foam layer includes a non-cross-linked olefin-based elastomer, the first non-foam layer has a maximum static friction coefficient determined by JIS K7125 of 2.0 or more, the second non-foam layer has a maximum static friction coefficient determined by JIS K7125 of 1.0 or less, and a ratio represented by [basis weight of first non-foam layer (a)]/[basis weight of second non-foam layer (b)] is 0.5 to 2.0.