Single-Copolymer Sealing Insert for PVC-Free Container Closures
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Solution Overview
Problem
Existing container closures containing halogenated materials, such as PVC, pose health risks and disposal challenges, while existing polymer-based closures lack the necessary balance of properties for demanding applications, including elasticity, temperature resistance, and ease of processing.
Innovation Solution
A container closure with a sealing insert made from a single type of copolymer, preferably PP-based, such as PP/PE bipolymer or PP/PE/BU terpolymer, combined with conventional additives, ensuring elasticity, temperature resistance, and ease of processing without halogenated materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If halogenated materials such as PVC are used in sealing inserts, then processing ease and sealing properties are improved, but health risks and disposal difficulties arise
Solution Approach 1:
The patent changes the chemical composition parameters by completely eliminating halogenated materials and using only polyolefin copolymers (polypropylene and/or polyethylene) with specific molecular weight ranges and copolymerization degrees. This parameter change maintains processing capabilities while removing harmful health effects associated with halogenated materials.
Solution Approach 2:
The patent employs disposable sealing inserts made from inexpensive polyolefin copolymers that can be easily discarded after use. The sealing inserts are designed for single-use applications, eliminating the need for complex disposal systems while maintaining cost-effectiveness and health safety.
2Device complexity
If single polymer compounds are used in sealing inserts, then manufacturing simplicity is improved, but the balance of properties (elasticity, temperature resistance) deteriorates
Solution Approach 1:
The patent uses composite polyolefin materials consisting of multiple copolymer components (polypropylene and/or polyethylene) with different molecular weight distributions and copolymerization degrees. These composite materials achieve a balanced combination of elasticity, temperature resistance, and processing properties while maintaining manufacturing simplicity through a unified polymer system.
Solution Approach 2:
The patent applies local quality control by optimizing specific regions of the sealing insert with controlled copolymerization degrees and molecular weight distributions. Different areas of the sealing insert can have tailored polymer properties to achieve optimal local performance for sealing, elasticity, and temperature resistance without complicating the overall manufacturing process.
3Reliability
If the sealing insert is made harder to ensure tight sealing, then sealing performance is improved, but ease of opening deteriorates
Solution Approach 1:
The patent employs dynamic material properties where the sealing insert transitions from a hard, sealing-oriented state during closure to a softer, opening-friendly state during usage. The polyolefin copolymer composition provides initial hardness for effective sealing, then allows controlled softening during opening operations, enabling easy removal without compromising sealing integrity.
Solution Approach 2:
The patent applies preliminary action through the design of the sealing insert geometry and polymer composition to create a sealing mechanism that automatically adjusts its properties. The sealing insert is pre-configured with optimal copolymerization and molecular weight distribution to provide effective sealing, while the opening process benefits from pre-planned stress distribution and material flexibility that facilitate easy removal.
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 solution provides a cost-effective, health-safe, and easily disposable sealing insert that maintains a tight seal under varying pressures and temperatures, suitable for pasteurization and sterilization, while avoiding the drawbacks of halogenated materials.
Implementation Method 1
a sufficiently hard, but on the other hand also elastic material and is disposed in the container closure in a manner such that it comes into contact with the mouth of the container when the container closure is disposed on the container
Implementation Method 2
They should (for example in the case of carbonated beverages) be able to withstand a considerable internal pressure which, however, if exceeded, should yield in a controlled manner (pressure relieving valve action)
Data Source
AI summary
A container closure, in particular a vacuum screw closure, having a scaling insert which comprises or consists of a polymer material (except for PVC), the sealing insert comprising essentially only one type of copolymer, preferably only one copolymer and in addition to this only conventional additives.