Flexible Plastic Lining Forming for Recyclable Beverage Containers
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Solution Overview
Problem
Disposable paper cups made with laminated card, which contain a polymeric coating, cannot be fully recycled due to the coating inhibiting the decomposition of paper fibers and contaminating the pulp, leading to significant waste and environmental impact, with approximately 58 billion cups ending up in landfills annually in the USA.
Innovation Solution
A method of forming a flexible lining for containers using a plastics material that conforms exactly to the internal shape of the container, allowing for smooth contact and easy separation from the paperboard shell, enabling recycling by avoiding the need for stretching and minimizing waste, with the lining being formed around a former using heat welding and cutting techniques to create a seamless bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymeric coating is applied to paper-based substrate to create waterproof lining, then water resistance and liquid barrier properties are improved, but the material becomes difficult to recycle and contaminate paper pulp
Solution Approach 1:
The invention removes the polymeric coating entirely from the paper-based substrate. Instead, it uses a thin layer of food-grade plastic lining that is directly formed on the container interior without lamination, allowing the paper substrate to remain recyclable while providing the necessary water resistance.
Solution Approach 2:
Rather than coating the paper with plastic (plastic-on-paper approach), the invention inverts the approach by forming a plastic lining that conforms to the container shape, with the paper substrate serving as the structural outer layer. This reversal enables the plastic to be easily removed for recycling while maintaining water resistance.
2Use of energy by moving object
If laminated card is used to form disposable cups, then resource and energy efficiency is improved compared to plastic alone, but the cups cannot be recycled with unlaminated cardboard or pure plastic
Solution Approach 1:
The invention segments the container into two distinct parts: a paper-based substrate providing structural integrity and an separate thin plastic lining providing water resistance. This segmentation allows each material to be processed independently in recycling streams, with the plastic lining being removed and the paper substrate being recycled with unlaminated cardboard.
3Shape
If the lining is stretched to insert into the container, then the lining can conform to the container shape, but the thickness varies and the lining becomes prone to tearing
Solution Approach 1:
The plastic lining is pre-formed to match the exact internal dimensions and shape of the container before insertion. This preliminary shaping eliminates the need for stretching during installation, maintaining uniform thickness and preventing weak spots that would lead to tearing.
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 method allows for the production of containers that are environmentally friendly, recyclable, and maintain structural integrity for storing beverages and food items, while also enabling easy separation of the lining from the paperboard shell for recycling, reducing waste and environmental impact.
Implementation Method 1
heating means arranged to heat said edge region to substantially conform it to an edge portion of the end face of the former
Implementation Method 2
bonding means arranged to bond a sheet of plastics material to said conformed edge region of the sleeve to form a base of the lining
Data Source
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AI summary
This invention relates to a method of making a container having a separable inner lining and outer shell, and in particular to a method of forming a flexible lining for a container. This invention also relates to apparatus for use in such methods. A method of forming a flexible lining for a container comprises providing a former having a substantially flat end face and a perimeter surface extending from the end face, the former having external shape and dimensions substantially the same as the internal shape and dimensions of the container, forming a sleeve of plastics material around the perimeter surface of the former, an edge region of the sleeve extending beyond the end face of the former, heating the edge region to substantially conform the edge region to an edge portion of the end face of the former, and bonding a sheet of plastics material to the conformed edge region of the sleeve to form a base of the lining.