Recyclable Digital Ink Composition for Plastic Containers
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Solution Overview
Problem
The integration of digitally printed labels on plastic containers poses challenges during conventional recycling processes, as the adhesion of digital images to the containers is not compatible with current recycling methods, leading to contamination of recycled materials.
Innovation Solution
An ink composition for digital printing on plastic articles is developed, comprising a base ink, an ink removal-promoting additive, and a carrier. The removal-promoting additive, which can include hydrophilic and acidic components, facilitates the separation of cured ink droplets from the plastic surface when exposed to a liquid-based solution at elevated temperatures, aligning with recycling process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digitally printed labels are applied to plastic containers using conventional printing techniques, then the adhesion and quality of digital images are improved, but the compatibility with conventional recycling processes deteriorates, leading to contamination of recycled materials
Solution Approach 1:
The ink composition uses a solvent system with specific chemical parameters (ester and ketone components in defined ratios) that changes the adhesion characteristics of the printed label. This parameter modification allows the label to maintain strong adhesion during use but become removable during recycling processing, resolving the contradiction between adhesion reliability and recycling compatibility
Solution Approach 2:
The invention utilizes thermal phase transition of the solvent system during recycling processing. The solvent-based ink composition undergoes phase change when exposed to high temperatures during recycling, causing the ink to separate from the plastic container surface. This phase transition enables the label to be removed automatically during recycling while maintaining adhesion during normal use
2Ease of manufacture
If conventional labeling techniques are used on plastic containers, then manufacturing simplicity is maintained, but recyclability and quality of recycled materials deteriorate due to ink contamination
Solution Approach 1:
The invention converts the potential harm of solvent-based ink (which causes contamination) into a benefit by designing the solvent system to be selectively removable. The same solvent components that enable easy manufacturing and good adhesion also enable clean removal during recycling when exposed to high temperatures, transforming the contamination risk into a self-cleaning mechanism that protects recycled material quality
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 ink composition ensures strong adhesion of digital images to plastic containers during their useful life while allowing for efficient removal during recycling processes, maintaining the quality of recycled plastic materials.
Implementation Method 1
a carrier capable of dissolving at least a portion of the ink removal-promoting additive
Implementation Method 2
when a printed digital image is exposed to a liquid-based (e.g., water-based) solution at or about a predetermined elevated temperature
Implementation Method 3
the adhesion of digital images to the containers is not compatible with current recycling methods
Data Source
AI summary
The disclosure relates to ink compositions for digital printing on an external surface of a plastic article. The ink compositions comprise an ink removal-promoting additive. In some aspects, the ink removal-promoting additive can facilitate the separation or loosening of the image from the external surface of the article when the image is exposed to a liquid-based solution at an elevated temperature. Also disclosed are recyclable plastic articles having an external surface with an image printed thereon using the disclosed ink composition and methods for removing cured ink from a plastic container. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.