Polypropylene Barrier Laminate for Recyclable Collapsible Containers
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Solution Overview
Problem
Existing collapsible containers with barrier properties, such as collapsible tubes, are not suitable for recycling without laborious material separation due to the use of materials like aluminum, SiOx, EVOH, and polyethylene, which limits their recyclability and usability in mono-material recycling streams.
Innovation Solution
A collapsible container with a container laminate comprising at least three layers: an inner and outer polypropylene layer with a barrier layer sandwiched between them, where the barrier layer includes an oriented polyolefin foil, ensuring at least 90% of the container is made of polypropylene, and optionally coated with a polypropylene sheathing, to enhance recyclability and barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminate with barrier layer (aluminum, SiOx, EVOH, PA) is used to achieve fluid-tightness, then barrier properties are improved, but recyclability deteriorates due to laborious material separation
Solution Approach 1:
The patent extracts the barrier function from traditional multi-material laminates and implements it through a polypropylene-based solution. Specifically, it uses polypropylene homopolymer or copolymer as the base material with controlled crystallinity and molecular weight to achieve both barrier properties and recyclability, eliminating the need for aluminum, EVOH, or PA layers that would complicate recycling
Solution Approach 2:
The patent changes the physical and chemical parameters of polypropylene to achieve barrier properties. It specifies polypropylene homopolymer or copolymer with crystallinity of 40-70% and molecular weight of 50,000-500,000 g/mol, which provides both the required barrier performance and recyclability without needing separate barrier layers
2Reliability
If high density polyethylene is used for blown film production, then sealability is improved, but adaptability deteriorates due to limitations in production methods and recycled material usability
Solution Approach 1:
The patent changes the material parameter from high density polyethylene to polypropylene homopolymer or copolymer with specific crystallinity (40-70%) and molecular weight (50,000-500,000 g/mol). This parameter change maintains sealability while improving recyclability and production flexibility, as polypropylene can be more readily recycled and processed through various manufacturing methods including blown film production
Data Source
AI summary
For recyclability in a high value circular recycling material stream, a fluid-tight collapsible polyolefin container comprises a container body (5) formed of a container laminate (1) that is folded to a container-like body and fixed by sealing overlapping edge regions (2, 3) or by butt welding adjacent edges and optionally coated with a sheathing (4) of polypropylene to form the container body (5), said container body (5) being provided at one open end with a container head formed from polypropylene. The container laminate (1) is a laminate having at least three layers, an inner polypropylene layer (6) and an outer propylene layer (8) and a barrier layer (7) sandwiched between the outer polypropylene layer (8) and the inner polypropylene layer (6), wherein the barrier layer (7) comprises at least one polyolefin comprising oriented barrier foil like a monolayer foil (71) or a coextruded foil (72 with layers 72a, 72b) or a laminate thereof and wherein at least 70% by weight, preferably at least 90% by weight of all polymers of the container are made of polypropylene homopolymer and/or copolymer.