Olefin Packaging Laminate for Oxygen Barrier After Bending
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Solution Overview
Problem
Existing packaging materials face challenges in achieving high laminate strength and oxygen barrier properties after bending while minimizing residual solvent, particularly with the use of aluminum-free alternatives like PVDC, which pose environmental and recycling issues.
Innovation Solution
A packaging material comprising a base material, a barrier layer containing a hydrophilic resin, and an adhesive layer formed from a cured product of a polyol and isocyanate curing agent, with specific mass and permachor values, and an olefin content of 80% or more, optionally including an inorganic layered filler, to enhance laminate strength and oxygen barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mass per unit area of the adhesive layer is increased to impart sufficient barrier properties, then oxygen barrier properties improve, but residual solvent increases
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive layer by specifying a polyol with particular hydroxyl value range (30-80 mgKOH/g) and permachor value range (25-60), and controlling isocyanate group content (0.5-5.0 mmol/g). These parameter changes enable achieving sufficient oxygen barrier properties with a thinner adhesive layer (1.0-4.5 g/m²), thereby reducing residual solvent while maintaining barrier performance.
2Reliability
If conventional aluminum is used to achieve high oxygen barrier properties, then oxygen barrier properties improve, but recyclability deteriorates
Solution Approach 1:
The patent uses a polyol-based adhesive layer that is homogeneous in composition and can be fully integrated with plastic base materials. This eliminates the need for aluminum foil layers, enabling the entire packaging material to be recycled as a single plastic material while maintaining high oxygen barrier properties through the optimized adhesive layer formulation.
3Reliability
If PVDC coating is applied to achieve high oxygen barrier properties under high humidity, then oxygen barrier properties improve, but environmental harm increases due to chlorine gas and dioxins
Solution Approach 1:
The patent replaces the harmful PVDC coating with a polyol-based adhesive layer that provides equivalent or superior oxygen barrier properties without containing chlorine. The polyol formulation with specific hydroxyl value (30-80 mgKOH/g) and permachor value (25-60) creates a dense molecular structure that effectively blocks oxygen permeation, converting the need for a barrier coating into a benefit-free solution.
4Strength
If the adhesive layer mass per unit area is increased to improve laminate strength, then laminate strength improves, but residual solvent increases
Solution Approach 1:
The patent optimizes the adhesive layer parameters including polyol hydroxyl value (30-80 mgKOH/g), permachor value (25-60), and isocyanate group content (0.5-5.0 mmol/g) to achieve maximum bonding strength with minimal adhesive thickness (1.0-4.5 g/m²). This parameter optimization ensures sufficient laminate strength while minimizing residual solvent content.
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 packaging material achieves improved laminate strength and oxygen barrier properties after bending with reduced residual solvent, addressing the limitations of conventional aluminum-free materials.
Implementation Method 1
the adhesive layer is a layer containing a cured product of a polyol and an isocyanate curing agent (I)
Data Source
AI summary
Provided is a packaging material which has a base material 1, a barrier layer, an adhesive layer, and a base material 2, wherein: the barrier layer contains a hydrophilic resin; the adhesive layer contains a cured product of a polyol and an isocyanate curing agent (I); the permachor value of the polyol is 25-60; the mass per unit area of the adhesive layer is 1.0-4.5 g/m2; and the olefin content of the packaging material is 80% by mass or more in the total mass of the packaging material.