Heat-Sealable PET Resin Layer for Paper Containers
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Solution Overview
Problem
Current paper containers with polyethylene resin layers lack long-term flavor retention and heat-sealability at low temperatures, and those using PET resin have poor low-temperature heat-sealability and high oxygen permeability, making them unsuitable for storing beverages that require long-term preservation at ordinary temperatures.
Innovation Solution
A laminated material comprising a paper substrate layer, an adhesive layer, a barrier layer, and a heat-sealable PET resin layer with a non-crystal portion of 85% or more, which includes a polyfunctional chain extender to enhance extrusion properties and a barrier layer such as EVOH or aluminum foil for improved oxygen barrier ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyethylene resin layer is used for heat-sealing, then low-temperature heat-sealability is improved, but flavor retention deteriorates
Solution Approach 1:
The patent uses a composite resin layer comprising PET resin and a specific amount of polyethylene resin (5-50 parts by weight) to combine the heat-sealing properties of polyethylene with the flavor-resistant properties of PET, resolving the contradiction between heat-sealability and flavor retention
Solution Approach 2:
The patent optimizes the composition ratio of PET resin to polyethylene resin within specific ranges (PET: 50-95 parts, polyethylene: 5-50 parts) to achieve the optimal balance between heat-sealing performance and flavor resistance, transforming the material parameters to resolve the contradiction
2Object-generated harmful factors
If PET resin is used for flavor retention, then flavor-keeping quality is improved, but low-temperature heat-sealability deteriorates
Solution Approach 1:
The patent creates a composite resin layer combining PET resin with polyethylene resin to maintain PET's flavor-resistant characteristics while incorporating polyethylene's heat-sealing capability, thus resolving the contradiction between flavor retention and heat-sealability
Solution Approach 2:
The patent applies different functional properties to different components of the composite resin layer: PET resin provides flavor resistance while polyethylene resin provides heat-sealing ability, allowing each material to fulfill its specific function locally within the composite structure
3Object-affected harmful factors
If PET resin is used for oxygen barrier, then oxygen permeability is improved, but long-term keeping quality at ordinary temperature deteriorates
Solution Approach 1:
The patent uses a composite structure with PET resin layer and barrier layer (EVOH, PVDC, or aluminum foil) to achieve both low oxygen permeability and long-term keeping quality by combining the oxygen barrier properties of PET with the superior barrier performance of the intermediate barrier layer
Solution Approach 2:
The patent divides the packaging structure into multiple functional layers: paper substrate layer, adhesive layer, barrier layer, and PET resin layer, where each layer performs a specific function - the barrier layer provides oxygen barrier and the PET layer provides flavor resistance and heat-sealing, thus resolving the contradiction through functional segmentation
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 provides paper containers with excellent low-temperature heat-sealability, minimal flavor absorption, and enhanced oxygen barrier properties, enabling long-term storage of beverages at ordinary temperatures without significant oxygen permeation.
Implementation Method 1
the oxygen barrier ability of PET resin is 60 ml/m2·25 μm·D·atm, which is superior to the oxygen barrier ability of polyethylene resin of 6,000 ml/m2·25 μm·D·atm by about 100 times
Implementation Method 2
heat-sealing ability necessary for fabricating into the paper container is imparted by disposing a PET resin layer
Implementation Method 3
the resulting PET resin layer has a crystal portion of less than 15% and a non-crystal portion of 85% or more
Implementation Method 4
adding a chain extender composed of styrene-methyl (metha) acrylate-glycidyl methacrylate to PET resin
Implementation Method 5
adhesive for paper layer/first adhesive for barrier layer
Data Source
AI summary
Provided is a paper container for foods capable of being fabricated by heat sealing which does not absorb flavors, such as limonene, and capable of storing a long period at ordinary temperature. The laminated material for paper containers is composed of paper substrate layer/adhesive for paper layer/first adhesive for barrier layer/barrier layer/second adhesive for barrier layer/heat-sealable PET resin layer, has an oxygen gas barrier ability of 2.0 ml/m2·D·atm or less, and the heat-sealable PET resin layer is made having a crystal portion of less than 15%, non-crystal portion of 85% or more.