Gas Barrier Multilayer Body Using Silane Crosslinking
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Solution Overview
Problem
Existing gas barrier multilayer bodies using PVA-based polymers fail to maintain gas barrier properties in high-humidity environments and are limited to dry object packaging due to moisture-induced degradation of hydrogen bonds.
Innovation Solution
A coating liquid containing a carboxyl group-containing polymer, polyvalent metal-containing particles, a surfactant, a silicon-containing compound, and an organic solvent, with specific ratios and compositions that enhance crosslinking and adhesion, forming a gas barrier laminate that withstands high-temperature and high-humidity environments and heavy-duty use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVA-based polymer layer is used as gas barrier coating, then gas barrier performance is improved in low-humidity atmosphere, but gas barrier properties significantly deteriorate in high-humidity atmosphere due to moisture absorption weakening hydrogen bonds
Solution Approach 1:
The patent combines PVA-based polymer with inorganic layered compounds (such as montmorillonite) to create a composite coating layer. The inorganic layers provide physical barriers that maintain gas barrier properties even when PVA hydrogen bonds are weakened by moisture, thus resolving the contradiction between gas barrier performance and stability in high-humidity conditions
Solution Approach 2:
The patent modifies the chemical structure of the PVA-based polymer by introducing hydrophobic groups or crosslinking agents to reduce moisture absorption. This parameter change in the polymer's chemical composition prevents hydrogen bond weakening in high-humidity environments while maintaining gas barrier performance
2Reliability
If high-temperature heat treatment is performed to form crosslinked structure, then gas barrier properties under high-humidity atmosphere are improved, but severe degradation of polyolefin substrate occurs
Solution Approach 1:
The patent lowers the heat treatment temperature parameter from conventional high temperatures (150°C or higher) to a milder range (below 100°C), which is sufficient to form crosslinked structures in the coating layer without causing degradation of the polyolefin substrate
Solution Approach 2:
The patent introduces a silane coupling agent as an intermediary substance that facilitates crosslinking at lower temperatures. The silane forms a bridge between the PVA-based polymer and the substrate, enabling effective crosslinked structure formation without requiring high-temperature heat treatment that would damage the substrate
3Ease of manufacture
If polycarboxylic acid-based polymer and polyvalent metal compound are both present in coating liquid, then ion-crosslinking can occur without high-temperature treatment, but precipitate formation prevents uniform film formation
Solution Approach 1:
The patent divides the coating process into separate steps: first applying the polycarboxylic acid-based polymer coating, then separately applying the polyvalent metal compound coating. This segmentation prevents precipitate formation during mixing while enabling ion-crosslinking between the two layers, achieving both low-temperature manufacturing and uniform film formation
Solution Approach 2:
The patent transitions from a single-layer coating approach to a multi-layer coating structure, where the polymer and metal compound are applied in different layers. This dimensional change in the coating architecture allows ion-crosslinking to occur at the interface between layers without the precipitate formation problem that occurs when both components are mixed in the same layer
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 gas barrier laminate maintains excellent gas barrier performance even under heavy-duty conditions such as bending, after exposure to high-temperature and high-humidity environments, and supports the use of polyolefin substrates without severe degradation.
Implementation Method 1
a layer containing a polycarbonate-based polymer such as polyacrylic acid is formed, and then the polycarbonate-based polymer is ion-crosslinked with polyvalent metal ions
Implementation Method 2
the silicon-containing compound (d) is at least one selected from a group consisting of silane coupling agents represented by general formulas (1) and (2) below and hydrolysates and condensates thereof
Implementation Method 3
the silicon-containing compound (d) is at least one selected from a group consisting of silane coupling agents represented by general formulas (1) and (2) below and hydrolysates and condensates thereof
Implementation Method 4
a coating liquid containing a carboxyl group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), a silicon-containing compound (d), and an organic solvent (e)
Data Source
Figure 1~2
AI summary
Provided by an embodiment of the present invention is a coating liquid for producing a gas barrier laminate, the coating liquid containing a carboxyl group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), a specific silicon-containing compound (d), and an organic solvent (e). In the coating liquid: the equivalence ratio (bt/at) of the product (bt) of the number of moles and the valency of the polyvalent metal contained in the polyvalent metal-containing particles (b) relative to the number of moles (at) of carboxyl groups contained in the carboxyl group-containing polymer (a) is 0.45 or more and 0.9 or less; and the molar ratio (dt/at) of the number of moles (dt) of the silicon-containing compound (d) relative to the number of moles (at) of the carboxyl groups is 0.7% or more and 7.5% or less.