Polypropylene Monomaterial Multilayer Structure for Hot Filling
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Solution Overview
Problem
Multilayer structures composed of different polymer layers or blends are challenging to recycle due to limited compatibility, leading to poor mechanical properties and recycling issues, particularly in applications requiring thermal resistance, such as hot filling or pasteurization, where PE/PE laminates lack sufficient thermal resistance and PP-based laminates suffer from mechanical property deterioration.
Innovation Solution
A polypropylene monomaterial multilayer structure is developed using extrusion lamination, comprising a first oriented polypropylene layer, a second non-oriented polypropylene layer, and a core layer of branched polypropylene, ensuring all layers are made of polypropylene composition to maintain mechanical and thermal properties while being fully recyclable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If PE/PE laminates are used to achieve ease of recycling, then recyclability is improved, but thermal resistance is insufficient for hot filling or pasteurization
Solution Approach 1:
The patent changes the material parameter from PE to PP (polypropylene) to achieve both thermal resistance and recyclability. PP provides sufficient thermal resistance for hot filling and pasteurization applications while maintaining recyclability through the monomaterial structure.
Solution Approach 2:
The patent uses a multilayer composite structure with different PP compositions (oriented and non-oriented layers) to achieve both thermal resistance and mechanical properties while maintaining recyclability through compatible polymer composition.
2Temperature
If PP-based laminates are used to achieve thermal resistance, then thermal properties are improved, but mechanical properties deteriorate
Solution Approach 1:
The patent creates a multilayer composite structure combining oriented PP layers (for mechanical strength and stiffness) with non-oriented PP layers (for thermal resistance and toughness). This composite approach allows both thermal and mechanical requirements to be satisfied simultaneously.
Solution Approach 2:
The patent applies different PP compositions to different layers: oriented PP in external layers for mechanical strength and non-oriented PP in core layers for thermal resistance, giving each layer the specific properties needed for its function.
3Strength
If multilayer structures with different polymer layers are used to achieve desired end product properties, then mechanical and sealing properties are improved, but recyclability deteriorates due to limited compatibility
Solution Approach 1:
The patent uses a monomaterial structure with all layers made from PP compositions, ensuring homogeneity of polymer type across all layers. This allows the entire multilayer structure to be recycled together as a single material type, overcoming the recyclability problems of multimaterial structures.
Solution Approach 2:
The patent uses a multilayer composite structure with different PP compositions (oriented and non-oriented layers) to achieve both thermal resistance and mechanical properties while being fully recyclable.
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 polypropylene monomaterial multilayer structure achieves improved mechanical and thermal properties without deteriorating mechanical performance, enhancing recyclability and suitability for temperature-resistant packaging applications.
Implementation Method 1
a core layer C) comprising at least one layer C-1) of a branched polypropylene, located between the first external layer A) and the second external layer B), wherein the core layer C) is extrusion laminated between the external layers A) and B)
Data Source
AI summary
The present invention is directed to a multilayer structure. More specifically, the present invention is directed to a polypropylene multilayer extrusion laminate structure which provides sufficient thermal resistance and mechanical properties, and which multilayer structure can be recycled. The present invention is further directed to a process for producing the multilayer structure by an extrusion lamination process.