Retort Packaging Laminate Sealant Composition
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Solution Overview
Problem
Retort packaging containers using polypropylene-based resins face issues with poor impact resistance at low temperatures and the presence of additives in sealant layers, while polyethylene-based resins have inferior heat resistance, making them unsuitable for retort processes and cold environments.
Innovation Solution
A laminate for retort packaging with a sealant layer composed of a polyethylene resin mixture of high-density, linear low-density, and high-pressure low-density polyethylenes, along with an oxygen absorption layer and a deodorizing layer, providing excellent heat resistance, impact resistance, and hygiene by eliminating the need for additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polypropylene-based resin is used for the sealant layer, then heat resistance and sealing properties are improved, but impact resistance at low temperature deteriorates
Solution Approach 1:
The patent applies composite materials by creating a multi-layer laminate structure where each layer serves a specific function. The sealant layer uses a composite resin composition combining polyethylene (for low-temperature impact resistance) with other polymers (to achieve heat resistance), while the barrier layer provides oxygen barrier properties. This composite approach resolves the contradiction by integrating materials with complementary properties rather than relying on a single material to satisfy all requirements.
Solution Approach 2:
The packaging structure is segmented into distinct functional layers: sealant layer, barrier layer, and optionally an oxygen absorption layer. This segmentation allows each layer to be optimized for its specific function - the sealant layer for sealing and temperature resistance, the barrier layer for oxygen protection, and the absorption layer for active oxygen scavenging. The segmentation resolves the technical contradiction by distributing functional requirements across multiple specialized components.
2Strength
If polyethylene-based resin is used for the sealant layer, then impact resistance at low temperature is improved, but heat resistance deteriorates
Solution Approach 1:
The sealant layer employs a composite resin composition that combines polyethylene (providing low-temperature impact resistance) with other polymer components (providing heat resistance). This composite material approach allows the sealant layer to simultaneously achieve both low-temperature toughness and high-temperature stability, resolving the contradiction between impact resistance and heat resistance that prevents using pure polyethylene in retort packaging.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the resin composition by adjusting the types and ratios of polymers used in the sealant layer. By changing the composition parameters - incorporating specific ratios of polyethylene, polypropylene, and other polymers - the material achieves a balance of properties that satisfies both low-temperature impact resistance and high-temperature heat resistance requirements for retort packaging.
3Reliability
If oxygen absorption layer is added to prevent oxidation, then storage properties are improved, but unpleasant odors are generated
Solution Approach 1:
The patent converts the harmful odor-generating byproducts of oxygen absorption into beneficial outcomes by incorporating an odor-neutralizing layer. This layer contains activated carbon or other odor-absorbing materials that capture and neutralize the unpleasant odors produced during the oxygen absorption process. The harmful odors are thus converted into a manageable side effect, allowing the beneficial oxygen absorption function to proceed while eliminating the detrimental odor issue.
Solution Approach 2:
An intermediary odor-neutralizing layer is introduced between the oxygen absorption layer and the product space. This intermediary layer contains activated carbon or other odor-absorbing materials that mediate the interaction between the oxygen absorption process and the packaged product, capturing unpleasant odors while allowing the oxygen absorption function to operate effectively. The intermediary resolves the contradiction by filtering out the harmful odor byproducts while preserving the beneficial oxygen scavenging action.
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 laminate achieves superior heat resistance and impact resistance at low temperatures, ensuring the integrity of retort packaging containers and improving storage properties by absorbing oxygen, while maintaining transparency and deodorizing functionality.
Implementation Method 1
laminates an oxygen-absorbing film having an oxygen absorption layer
Implementation Method 2
a deodorizing layer that captures odorous components emitted from the oxygen absorption layer
Implementation Method 3
The sealant layer which constitutes the surface that contacts the contents of the retort packaging container requires heat sealing properties
Data Source
AI summary
The invention provides a laminate for retort packaging that can be applied to a retort packaging container having excellent bag drop strength at low temperature, and a container that uses this laminate for retort packaging. A laminate for retort packaging (10), wherein a sealant layer (21) is formed of a resin that is composed mainly of a polyethylene resin composition composed of at least 30% by mass but not more than 50% by mass of a high-density polyethylene, at least 40% by mass but not more than 50% by mass of a linear low-density polyethylene, and at least 10% by mass but not more than 20% by mass of a high-pressure low-density polyethylene.