Peelable Lidstock Sealing Layer Composition
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Solution Overview
Problem
Existing peelable and sealable lidstock materials for containers lack an optimal combination of peel force, burst strength, and footprint appearance on the container sealing surface after peeling.
Innovation Solution
A peelable and sealable lidstock with a sealing layer comprising 70-89% by weight of a copolymer (A) including polymerized olefin and ethylenically unsaturated carboxylic acid monomers, 10-29% by weight of a copolymer (B) including polymerized (meth)acrylate ester monomers, and 1-10% by weight of inorganic particles with specific particle size characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sealing layer is designed for high burst strength, then the seal becomes more robust, but the peel force becomes too high and inconsistent
Solution Approach 1:
The patent applies parameter changes by carefully controlling the copolymer composition ratios (ethylene content 1-15 mole percent), molecular weight distribution, and crystallinity of the polyolefin copolymer. These parameter adjustments create a sealing layer with optimized balance between burst strength and peel force, allowing the material to exhibit appropriate mechanical properties for both sealing robustness and controlled peeling.
Solution Approach 2:
The patent uses composite materials by combining polyolefin copolymer with other polymers or additives to create a multi-component sealing layer formulation. This composite approach allows integration of materials with complementary properties - the polyolefin copolymer provides burst strength while the additional components modulate peel characteristics, achieving a balanced performance that neither material could provide alone.
2Adaptability or versatility
If the heat seal temperature range is widened, then sealing flexibility improves, but seal consistency and footprint uniformity deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the copolymer composition (ethylene content 1-15 mole percent) and molecular characteristics to create a sealing layer with a broad heat seal window. The specific copolymer structure enables the material to maintain consistent sealing performance across a wide temperature range (typically 100-200°C), providing both adaptability to different sealing conditions and consistency in seal quality and footprint uniformity.
3Strength
If peel force is increased for better sealing, then seal strength improves, but the footprint appearance becomes uneven and inconsistent
Solution Approach 1:
The patent applies parameter changes by precisely controlling the copolymer composition (ethylene content 1-15 mole percent), molecular weight, and crystallinity to achieve optimal peel force levels. These parameter optimizations ensure that the seal strength is sufficient for robust sealing while maintaining controlled peeling behavior that produces even, consistent footprints on the container sealing surface, avoiding the uneven appearance associated with excessive or inconsistent peel forces.
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 achieves a consistent peel force over a wide range of heat seal temperatures, even and consistent cohesive failure, high burst strength, and a distinct uniform footprint on the container sealing surface after peeling.
Implementation Method 1
the lidstock is heat sealed directly to the metal surface
Implementation Method 2
even and consistent cohesive failure in the seal layer upon peeling
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A peelable and sealable lidstock constructed from a metal substrate and a sealing layer, the sealing layer containing (A) from 70-89% by weight of a copolymer having one or more polymerized olefin monomers and one or more polymerized ethylenically unsaturated (poly)carboxylic acid monomers, (B) from 10-29% by weight of a copolymer comprising one or more polymerized (meth)acrylate ester monomers, and (C) from 1-10% by weight of one or more inorganic particles characterized by a mass median diameter (D50) comprised between 1 and 5 micron.