Water-Soluble Primer Layer for Coating Stability and Recyclability
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Solution Overview
Problem
Conventional film-paper composites used in bag and sack production suffer from line breakage during folding, leading to a lower quality appearance and recyclability issues due to the use of ecologically problematic chemicals.
Innovation Solution
A purely fiber-based paper with a water-soluble polyvinyl alcohol primer layer applied to the surface, which prevents line breakage and enhances recyclability by forming a mechanical interface for further layer application, while being environmentally friendly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a film-paper composite is used to prevent coating break during folding, then the protective function and coating stability are improved, but the recyclability deteriorates due to ecologically problematic chemicals
Solution Approach 1:
The patent removes the plastic film layer from the composite structure, extracting the harmful component while retaining the paper substrate. The coating stability function is transferred to a water-soluble primer layer applied directly to the paper, eliminating the need for non-recyclable film materials.
Solution Approach 2:
The patent changes the chemical properties of the primer layer from water-insoluble (in conventional composites) to water-soluble. This parameter change enables the primer to be removed during recycling processes, improving recyclability while maintaining coating stability through the water-soluble polymer matrix.
2Manufacturing precision
If a thick coating is applied to achieve high print quality, then the print quality is improved, but the tendency for coating break during folding increases
Solution Approach 1:
The patent creates a multi-layer composite structure consisting of paper substrate, water-soluble primer layer, and pigment coating. The primer layer acts as a flexible bonding interface that accommodates folding stresses, preventing coating break while maintaining print quality through proper adhesion and surface properties.
Solution Approach 2:
The water-soluble primer layer serves as an intermediary between the paper substrate and the pigment coating. It provides a flexible intermediate layer that absorbs mechanical stresses during folding, preventing direct stress transmission to the brittle pigment coating and thus preventing coating break.
3Object-affected harmful factors
If a water-soluble primer layer is applied to improve recyclability, then the environmental compatibility is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent combines the primer layer application and coating application into a single integrated process step. The water-soluble polymer solution is applied along with or immediately followed by the pigment coating, allowing both layers to be deposited simultaneously and dried together, thereby simplifying the manufacturing process despite the additional functional 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 water-soluble primer layer stabilizes the coating, prevents line breakage, and ensures high recyclability of the paper and end products, maintaining a visually desirable appearance and improving the shelf life of packaged goods.
Implementation Method 1
A water-soluble primer layer, in particular a water-soluble polyvinyl alcohol primer layer, is applied to the coating
Data Source
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AI summary
Paper, in particular purely fiber-based paper, the surface of which has a coating on one or both sides, characterized in that a water-soluble primer layer is applied to the coating.