Recyclable Plastic Container Label Separation via Thermal Washing
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Solution Overview
Problem
Conventional methods for producing recyclable plastic packaging with labels result in significant CO2 emissions due to complex material sourcing and handling, inefficient waste management, and challenges in separating and recycling label materials from the container materials after shredding.
Innovation Solution
The method involves printing polyolefin or PET films on one or both sides and laminating them with a siliconized carrier, using environmentally friendly water-based adhesives, and selecting materials for easy separation in a warm washing solution, allowing for efficient recycling of label and container materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-layered adhesive labels with separate backing, adhesive, and face stock are used, then the label adheres firmly to the container, but the production process generates significant CO2 emissions due to separate material deliveries and multiple transport routes
Solution Approach 1:
The patent combines the backing material, adhesive layer, and face stock into a single integrated label structure. The face stock is directly bonded to the backing material in one manufacturing process, eliminating the need for separate deliveries and multiple transport routes between different manufacturers, thus significantly reducing CO2 emissions while maintaining label adhesion performance
Solution Approach 2:
The label is pre-assembled with the adhesive layer already bonded to the backing material before printing. This preliminary assembly eliminates subsequent transport steps and reduces the number of manufacturing operations required, thereby reducing emissions associated with material handling and transportation
2Loss of information
If conventional adhesive labels are used, then the label provides product information, but the separation and recycling of label materials from container materials is difficult after shredding
Solution Approach 1:
The patent employs a adhesive layer with specific thermal properties that allow it to be selectively removed from the container material through heating in a washing solution. The adhesive's bond strength changes with temperature, enabling easy separation of label materials from the container after shredding, while the printed information on the face stock remains intact for recycling
Solution Approach 2:
The label is designed as a separable multi-component structure where the adhesive layer can be independently removed from the face stock and container material. This segmentation allows the container material to be recycled separately from the label materials, improving the overall recycling process while maintaining product information on the face stock
3Ease of manufacture
If the label is removed from the container in a washing solution, then the label materials can be separated from the container, but energy is consumed for heating the washing solution to ≥ 50°C
Solution Approach 1:
The adhesive layer is formulated with temperature-dependent bond characteristics that allow it to be selectively activated and removed at moderate temperatures (≥ 50°C). This parameter change in the adhesive's physical properties enables effective label removal without requiring excessive heating energy, while still achieving complete separation of label materials from the container
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
This approach reduces waste, minimizes CO2 emissions, and enables effective separation and recycling of label and container materials, improving the sustainability and energy efficiency of the packaging production process.
Implementation Method 1
separated from the adhering label parts in a warm washing solution with a temperature of ≥ 50°C
Implementation Method 2
the flakes resulting from shredding the labeled container with adhering label parts are separated from the adhering label parts in a warm washing solution
Data Source
AI summary
The invention relates to a method for the sustainable and energy-saving production of recyclable packaging which consists of a plastic container provided with a label, the label containing a printed polyolefin or PET film which is adhesively bonded to the container. According to the invention, the polyolefin or PET film is first printed on the front and/or reverse, and the waste material produced before and during printing is removed and reused as recycling material. The printed polyolefin or PET film is then laminated on a siliconised backing, or the composite consisting of this backing and the film is fed to the container for labelling, the materials of the aforementioned parts being selected such that either a label made of PET is adhesively bonded to a container made of a polyolefin, or a label made of a polyolefin is adhesively bonded to a PET container, so that the flakes with adhering label parts produced after the container provided with a label has been shredded are separated from adhering label parts in a warm washing solution at a temperature of ≥ 50°C, and the floating parts consisting of pure polyolefin and the parts made of PET which sink owing to the material can be separated from each other and fed to a recycling stage.