Recyclable Stand Up Pouch Laminated Structure
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Solution Overview
Problem
Stand up pouches made from a single material of polyethylene face challenges in achieving a balance of stiffness and optical properties, as high density polyethylene provides stiffness but poor optical properties, while linear low density polyethylene offers good optical and physical properties but lacks stiffness, making them difficult to recycle and design effectively.
Innovation Solution
A laminated structure composed of multiple layers of polyethylene, including high density polyethylene for stiffness, lower density polyethylene for impact resistance, and a sealant polyethylene, with Machine Direction Orientation and nucleating agents to enhance optical and stiffness properties, allowing for a recyclable stand up pouch with improved balance of properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high density polyethylene (HDPE) is used to provide stiffness, then the structural rigidity is improved, but the optical properties (haze and gloss) deteriorate
Solution Approach 1:
The pouch is divided into multiple functional layers: HDPE layers provide stiffness and structural integrity, while LLDPE layers provide optical clarity and impact resistance. This segmentation allows each material to perform its specialized function without compromise.
Solution Approach 2:
The invention uses a composite structure combining different polyethylene types (HDPE and LLDPE) in a laminated configuration. This composite approach achieves both stiffness (from HDPE) and good optical properties (from LLDPE) simultaneously, resolving the contradiction between these two properties.
2Illumination intensity
If linear low density polyethylene (LLDPE) is used to provide good optical and physical properties, then the optical properties are improved, but the stiffness deteriorates
Solution Approach 1:
The pouch structure segments optical functions from structural functions. LLDPE layers are positioned to provide optical clarity and impact resistance, while separate HDPE layers provide the necessary stiffness and rigidity for stand-up capability.
Solution Approach 2:
By combining LLDPE and HDPE in a laminated composite structure, the invention achieves both good optical properties (from LLDPE) and adequate stiffness (from HDPE), eliminating the need to choose one material over the other.
3Strength
If a laminate of PET and PE is used to achieve desirable balance of stiffness and optical properties, then the optical and stiffness properties are improved, but the recyclability deteriorates
Solution Approach 1:
The invention changes the material composition parameter from a mixed PET/PE laminate to an all-polyethylene laminate. By using different densities and types of polyethylene (HDPE and LLDPE) instead of different polymer families, the pouch maintains its mechanical properties while becoming recyclable through polyethylene-only recycling streams.
Solution Approach 2:
The composite structure uses compatible polyethylene materials (HDPE and LLDPE) that can be processed together and recycled together, unlike incompatible PET and PE materials. This allows the pouch to achieve the desired performance balance while maintaining recyclability within the polyethylene recycling infrastructure.
Data Source
AI summary
A recyclable Stand Up Pouch (SUP) is prepared using a polyethylene structure having a first web and a second web. Each of the first web and second web contains at least one layer of High Density Polyethylene (HDPE) to provide stiffness. The outer web also contains a layer of lower density polyethylene for improved optical properties. The 5 laminated structure is printed on one of the layers that form the interface between the two webs to protect the printing. This SUP design is suitable for preparing packages of a wide variety of flowable foods (including liquids and solids).