Paper Laminate Polyurethane Barrier Coating Without Aging
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Solution Overview
Problem
Conventional laminates coated with gas barrier polyurethane resin do not exhibit sufficient gas barrier properties without aging.
Innovation Solution
A laminate comprising a paper substrate with a density of 0.72 g/cm³ or more, an anchor coat layer, and a barrier coat layer containing a gas barrier polyurethane resin, which includes a secondary reaction product of an isocyanate group-terminated prepolymer and a chain extender, with specific components and layer thicknesses to enhance gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a paper substrate is coated with gas barrier polyurethane resin to provide gas barrier properties, then gas barrier performance is improved, but the laminate cannot exhibit sufficient gas barrier properties without aging
Solution Approach 1:
The patent applies preliminary action by pre-forming the polyurethane resin coating with specific compositional characteristics (using polyisocyanate components and active hydrogen group-containing components in defined ratios) before the actual gas barrier function is needed. This preliminary preparation of the coating chemistry allows the laminate to achieve gas barrier properties without requiring post-coating aging time, as the resin structure is already optimized for barrier performance.
Solution Approach 2:
The patent employs parameter changes by adjusting the chemical composition parameters of the polyurethane resin, specifically the ratio of polyisocyanate component to active hydrogen group-containing component (within 95:5 to 50:50 by mass), and controlling the molecular weight and structure of the resin. These parameter modifications enable the coating to achieve sufficient gas barrier properties immediately after application, eliminating the need for aging treatment.
2Reliability
If the paper substrate density is increased to improve gas barrier properties, then gas barrier performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the paper substrate density parameter to a specific range (0.72 g/cm³ or more) rather than maximizing it. This optimized parameter setting achieves sufficient gas barrier properties while avoiding the manufacturing complexities and cost increases associated with producing high-density paper substrates. The specific density threshold represents the point of diminishing returns where further density increases would not significantly improve barrier performance but would substantially increase manufacturing difficulty.
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 excellent gas barrier properties without the need for aging, with air resistance measured at 30000 s or more, ensuring effective gas barrier performance in an unaged state.
Implementation Method 1
the laminate has excellent gas barrier properties
Implementation Method 2
the gas barrier polyurethane resin contains a secondary reaction product of an isocyanate group-terminated prepolymer and a chain extender
Data Source
AI summary
A laminate includes a paper substrate, an anchor coat layer disposed at a one-surface side of the paper substrate, and a barrier coat layer disposed at a one-surface side of the anchor coat layer. The paper substrate has a density of 0.72 g/cm3 or more. The barrier coat layer contains a gas barrier polyurethane resin.