Gas Barrier Coating Composition for Humidity-Resistant Packaging
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Solution Overview
Problem
Existing gas barrier compositions for packaging materials exhibit poor coatability and stability when used as coating agents, particularly under high-humidity conditions, and require multiple application steps to achieve high barrier properties.
Innovation Solution
A gas barrier composition comprising a polyester polyol resin or polyurethane polyol resin with an acid value of 150 mg KOH/g or less, a divalent metal compound, and an organic solvent, which can be used as a one-component or two-component coating agent to form a laminate body with excellent barrier properties without significant gelation during solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carboxyl group-containing resin with high acid value (such as polyacrylic acid or polyvinyl alcohol) is used to achieve high oxygen barrier properties, then the oxygen barrier properties under dry conditions are extremely excellent, but the oxygen barrier properties significantly decrease under high-humidity conditions due to the hydrophilicity of the resin
Solution Approach 1:
The patent changes the chemical parameters of the resin by controlling the acid value to be 150 mg KOH/g or less, and specifically using polyester polyol or polyurethane polyol resins with balanced hydrophilicity and hydrophobicity. This parameter optimization resolves the contradiction between achieving high oxygen barrier properties and maintaining performance under high-humidity conditions.
2Reliability
If a gas barrier composition with high alcohol content (85 to 98 wt%) and low moisture content (1% or less) is used to achieve high gas barrier properties and good storage stability, then the composition shows high gas barrier properties and good storage stability, but the coatability and stability as a coating agent are slightly inferior
Solution Approach 1:
The patent optimizes the composition parameters by controlling the alcohol content to 70-90 wt% (rather than 85-98 wt%), moisture content to 0.1-10% (rather than 1% or less), and acid value to 150 mg KOH/g or less. These parameter adjustments simultaneously improve gas barrier properties, storage stability, and coatability.
3Reliability
If the acid value of the polyester polyol resin or polyurethane polyol resin is high, then the gas barrier properties are enhanced, but partial gelation occurs as the solvent evaporates, which reduces the coatability
Solution Approach 1:
The patent identifies and controls the critical parameter of acid value, setting it to 150 mg KOH/g or less. This parameter control prevents excessive gelation during solvent evaporation while maintaining sufficient gas barrier properties, thereby resolving the contradiction between barrier performance and coatability.
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 composition maintains coatability and stability while providing high gas barrier properties, suitable for packaging materials that require heat resistance and moisture resistance, especially for food, daily necessities, and medical applications.
Implementation Method 1
a gas barrier composition comprising (A) a polyester polyol resin or polyurethane polyol resin having an acid value, (B) a divalent metal compound
Implementation Method 2
when used as a coating agent, the composition is slightly inferior in coatability and stability
Data Source
AI summary
A gas barrier composition including (A) a polyester polyol resin or polyurethane polyol resin having an acid value, (B) a divalent metal compound, and an organic solvent, in which the acid value of the polyester polyol resin or polyurethane polyol resin (A) in the composition is 150 mgKOH/g or less; a gas barrier coating agent containing the composition described above; a laminate body having a coat layer obtained by applying the coating agent described above; and a packaging material. It is preferable that the divalent metal compound (B) is at least one member selected from zinc compounds, magnesium compounds, and calcium compounds.