Barrier Coating Composition for Crack-Resistant Packaging
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Solution Overview
Problem
Conventional coatings for packaging materials fail to provide effective grease and water vapor barriers while resisting cracking, adhering to adjacent layers during processing, and ensuring recyclability, especially for foodstuff and consumable liquids packaging.
Innovation Solution
A barrier coating composition comprising 30-70 weight-% of styrene (meth)acrylate copolymer with a glass transition temperature ≤20°C, 30-70 weight-% of polyvinyl alcohol, and up to 5.0 weight-% of a cross-linker, applied on a substrate with lignocellulosic fibers, which maintains barrier properties and prevents cracking during creasing and folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluorochemicals are used in coating compositions to provide desired barrier properties with resistance to cracking, then grease and water vapour barrier properties are improved, but environmental compatibility deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by replacing fluorochemicals with a specific polymer combination (styrene-methacrylate copolymer with Tg ≤20°C and polyvinyl alcohol) that achieves comparable barrier properties without the environmental harm of conventional fluorochemicals
Solution Approach 2:
The invention uses a composite coating system combining styrene-methacrylate copolymer and polyvinyl alcohol in specific ratios (30-70 wt% each) to achieve the desired barrier properties as an alternative to single-component fluorochemical coatings
2Ease of operation
If the coating layer softens under high pressure and high temperature during manufacturing, then ease of operation improves, but blocking occurs and productivity deteriorates
Solution Approach 1:
The patent optimizes the glass transition temperature parameter of the copolymer (Tg ≤20°C) to achieve the right balance: soft enough for easy coating application but stable enough to prevent blocking during high-speed manufacturing and converting processes
3Reliability
If traditional plastic films are laminated on the surface of paper or board to provide barrier properties, then grease and water vapour barrier properties are improved, but recyclability deteriorates
Solution Approach 1:
The patent changes the material state from laminated plastic films to a polymer-based coating that can be applied directly to the paper or board surface, maintaining barrier properties while enabling recycling through repulping processes
Solution Approach 2:
The invention extracts the barrier function from separate laminated plastic films and integrates it into a coating that is chemically compatible with the paper or board substrate, allowing the entire structure to be recycled together
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 coating composition provides excellent resistance to cracking, maintains barrier properties when folded, and supports recyclability, ensuring optimal performance for packaging applications while minimizing environmental impact.
Implementation Method 1
styrene (meth)acrylate copolymer, which is polymerised in the presence of a stabiliser, and which has a glass transition temperature Tg≤20° C.
Implementation Method 2
provide excellent grease and water vapour barrier properties
Implementation Method 3
at the most 5.0 weight-% of a cross-linker, which reacts with —OH or —COOH groups
Data Source
AI summary
A barrier coating composition is disclosed including 30-70 weight-% of a styrene (meth)acrylate copolymer, polymerised in the presence of a stabiliser, and the styrene (meth)acrylate copolymer having a glass transition temperature Tg≤20° C., preferably ≤10° C., 30-70 weight-% of a polyvinyl alcohol, and at most 5.0 weight-% of a cross-linker, reacting with —OH or —COOH groups. Further disclosed is a sheet-like product coated with the coating composition.