Polymer Composition for Stable Heat Sealing
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Solution Overview
Problem
Current polymer compositions for heat sealing do not provide sufficient seal strength in the peelable seal portion over a wide temperature range, and there is a need for a technology that maintains high seal strength in both low-temperature peelable and high-temperature lock seals with minimal temperature dependence.
Innovation Solution
A polymer composition comprising an ionomer with an ethylene/α,β-unsaturated carboxylic acid copolymer and an ethylene/α,β-unsaturated carboxylic acid/α,β-unsaturated carboxylic acid ester terpolymer, along with a propylene-based polymer, where the mass ratio of the unsaturated carboxylic acid ester is adjusted to 1-4.5% in the ionomer, ensuring stable seal strength over a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polymer compositions (ethylene-based polymers or ionomers) are used for heat sealing, then seal strength can be improved, but the seal strength varies significantly with temperature and cannot maintain stable performance over a wide temperature range
Solution Approach 1:
The patent uses a composite material system consisting of three components: (A) an ionomer containing ethylene/α,β-unsaturated carboxylic acid copolymer units, (B) an ethylene/α,β-unsaturated carboxylic acid/α,β-unsaturated carboxylic acid ester t copolymer units, and (C) a propylene-based polymer. This composite structure combines materials with different thermal properties to achieve both high seal strength and temperature stability. The specific composition ranges (60-95 mass% ionomer, 5-40 mass% t copolymer, 5-20 mass% propylene-based polymer) are optimized to balance seal strength and temperature independence.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the mass percentage of each polymer component and the mass of α,β-unsaturated carboxylic acid ester units within the ionomer structure. By adjusting these compositional parameters, the invention achieves a seal strength that remains stable (variation within ±20%) across a wide temperature range from 80°C to 150°C, while maintaining peelable seal properties.
2Strength
If the seal strength is increased for lock seal applications, then the peelable seal becomes difficult to open, but if the seal strength is decreased for easy peeling, then the lock seal strength becomes insufficient
Solution Approach 1:
The patent applies local quality by creating distinct sealing zones within the same polymer composition. The composition is designed to exhibit different seal strength characteristics at different temperatures: at high temperatures (150°C or higher), it provides strong lock seal (10 N/10 mm or higher), while at low temperatures (80-130°C), it provides peelable seal with controlled strength (3-8 N/10 mm). This temperature-dependent local differentiation allows both functions in a single material system.
Solution Approach 2:
The patent utilizes the dynamic property of polymer materials where seal strength changes with temperature. The polymer composition dynamically adjusts its sealing characteristics based on the applied temperature, transitioning from strong adhesion at high temperatures (for secure lock seal) to controlled adhesion at low temperatures (for easy peeling). This dynamic behavior is achieved through the specific combination of ionomer, t copolymer, and propylene-based polymer with optimized ratios.
3Adaptability or versatility
If a wide temperature range is used for peelable seal formation, then the seal strength becomes unstable and varies with temperature, but if a narrow temperature range is used, then the operational flexibility is reduced
Solution Approach 1:
The patent employs composite materials with three specifically selected polymer components that work synergistically to achieve both wide temperature adaptability and seal strength stability. The ionomer provides baseline sealing performance, the t copolymer contributes to low-temperature sealability, and the propylene-based polymer enhances temperature resistance. This composite structure enables stable seal strength (variation within ±20%) across an expanded temperature range of 80°C to 150°C.
Solution Approach 2:
The patent applies parameter changes by optimizing the mass percentages of each component and the specific mass of α,β-unsaturated carboxylic acid ester units (1-4.5 mass% of the ionomer) to broaden the effective sealing temperature range while maintaining consistency. This compositional parameter optimization allows the material to function effectively from 80°C to 150°C with controlled seal strength variation.
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 polymer composition achieves high seal strength in both low-temperature peelable and high-temperature lock seals, with reduced temperature dependence, allowing for a stable and strong peelable seal over a wide temperature range, exceeding the seal strength of existing technologies.
Implementation Method 1
heat sealing in which a sealing section can be peeled and opened
Implementation Method 2
forming the lock seal on the back side or bottom under high temperature conditions
Data Source
AI summary
Provided is a polymer composition including (A) an ionomer containing an ethylene/α,β-unsaturated carboxylic acid copolymer and an ethylene/α,β-unsaturated carboxylic acid/α,β-unsaturated carboxylic acid ester terpolymer, and (B) a propylene-based polymer, wherein the mass of constituent units derived from the α,β-unsaturated carboxylic acid ester is from 1 to 4.5% by mass of the entire mass of the ionomer. Through this, a high seal strength may be obtained in a high-temperature range when forming a lock seal, while a high seal strength, as compared with the related art, can be stably obtained over a wide temperature range with a temperature dependence suppressed when forming a peelable seal.