Deinking Primer Composition for Plastic Substrate Recycling
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Solution Overview
Problem
Existing recycling methods for plastic flexible packaging materials face challenges in efficiently removing printing inks without impairing the recyclability and quality of the materials, particularly due to the limited heat resistance of ink binders and the coloring effect of pigments.
Innovation Solution
A deinking primer composition is developed, comprising a binder component with a polymeric backbone and pendent hydroxy or carboxy groups that are esterified, acetalised, or ketalised, allowing the primer layer to be dissolvable in an alkaline aqueous medium while maintaining good overprintability and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a releasing layer with high water solubility is used to enable easy ink removal, then the deinking efficiency is improved, but the water resistance under normal use conditions deteriorates
Solution Approach 1:
The binder component uses controlled esterification or acetalisation of hydroxy or carboxy groups to precisely tune the acid value (0-50 mg KOH/g) and hydroxyl value (0-600 mg KOH/g), creating a releasing layer with optimal balance between water resistance during use and water solubility during deinking
Solution Approach 2:
The deinking primer composition comprises a binder component with specific polymeric backbone structure containing pendent hydroxy or carboxy groups that are partially esterified or acetalised, creating a composite material with dual functionality: water resistance from the polymeric backbone and water solubility from the remaining hydroxy/carboxy groups
2Manufacturing precision
If conventional printing inks are applied to plastic substrates, then the print quality is improved, but the recyclability and transparency of the material deteriorate due to pigment coloring
Solution Approach 1:
The releasing layer is designed to be selectively removed from the plastic substrate through water treatment, extracting the ink layer along with the releasing layer while leaving the transparent plastic substrate intact and recoverable
Solution Approach 2:
The releasing layer is applied as a preliminary layer before printing, facilitating subsequent ink removal through its water solubility, thereby enabling easy separation of ink from the substrate during recycling
3Productivity
If the plastic material is processed at higher temperatures during extrusion, then the processing efficiency is improved, but the quality of recycled product deteriorates due to deterioration of ink binders and pigments
Solution Approach 1:
The ink and releasing layer are removed before the extrusion process, eliminating the harmful effects of high-temperature processing on ink binders and pigments, thereby enabling high-quality recycling through standard extrusion procedures
Solution Approach 2:
Deinking is performed as a preliminary step before extrusion, removing the temperature-sensitive ink components prior to high-temperature processing, thus protecting the ink binders and pigments from thermal deterioration
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 deinking primer composition enables efficient removal of printing inks from plastic substrates, ensuring the quality and transparency of recycled materials, and facilitating their reuse in packaging applications.
Implementation Method 1
a binder component that has a polymeric backbone with pendent hydroxy or carboxy groups that have been esterified or acetalised or ketalised to such an extent that the binder component has an acid value of 0-50 mg KOH/g or a hydroxyl value of 0-600 mg KOH/g, preferably 0-400 mg KOH/g, so that a primer layer prepared from said deinking primer composition is dissolvable in an alkaline aqueous medium
Data Source
AI summary
The present invention is related to a deinking primer composition for deinking of a substrate, wherein said deinking primer composition comprises a binder component that has a polymeric backbone with pendent hydroxy or carboxy groups that have been esterified or acetalised or ketalised to such an extent that the binder component has an acid value of 0-50 mg KOH/g or a hydroxyl value of 0-600 mg KOH/g, preferably 0-400 mg KOH/g, so that a primer layer prepared from said deinking primer composition is dissolvable in an alkaline aqueous medium.