Low Phosphorus Polyester Oxygen Scavenging Composition
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Solution Overview
Problem
Existing oxygen scavenging compositions in packaging materials often result in haze due to phase separation and require an induction period before oxygen scavenging can occur, which is not suitable for immediate protection of oxygen-sensitive products.
Innovation Solution
A composition comprising a polyester base polymer, a non-polymeric oxidizable organic compound, and a transition metal in a positive oxidation state, with the polyester base polymer containing less than 40 ppm of phosphorous, which allows for immediate oxygen scavenging without haze and induction period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric oxygen scavenging materials are blended into PET base polymer, then oxygen scavenging capability is improved, but haze is generated due to phase separation
Solution Approach 1:
The patent changes the molecular weight parameter of the oxygen scavenging component from high (polymeric) to low (low molecular weight), transforming it from a polymeric compound to a low molecular weight organic compound. This parameter change enables miscibility with PET base polymer, eliminating phase separation and haze while maintaining oxygen scavenging capability through the use of specific organic compounds containing oxidizable groups.
Solution Approach 2:
The patent extracts the essential oxygen scavenging functionality from polymeric structures and isolates it into low molecular weight organic compounds. By taking out the core oxidizable functional groups from their polymeric context, the invention achieves both miscibility with PET and oxygen scavenging capability, resolving the haze problem caused by polymeric phase separation.
2Reliability
If conventional oxygen scavengers are incorporated into plastic containers, then oxygen scavenging function is achieved, but induction period occurs before scavenging onset
Solution Approach 1:
The patent changes the chemical composition parameters by selecting specific low molecular weight organic compounds with readily oxidizable functional groups (such as compounds containing phenolic hydroxyl groups, enolic hydroxyl groups, or other easily oxidizable moieties). This parameter change in chemical structure enables immediate oxygen scavenging activity upon container filling, eliminating the induction period associated with conventional polymeric scavengers that require slower activation.
3Reliability
If polymeric scavenging materials are used in packaging walls, then oxygen barrier is improved, but clarity is reduced due to immiscibility
Solution Approach 1:
The patent applies parameter change by reducing the molecular weight of the oxygen scavenging component from polymeric to low molecular weight, which fundamentally alters the miscibility parameter with PET base polymer. This enables the oxygen scavenging material to dissolve uniformly in the PET matrix, achieving both effective oxygen barrier properties and high clarity without phase separation, as the low molecular weight compounds can penetrate and distribute uniformly within the polymer free volume.
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 achieves excellent oxygen scavenging properties and clarity in packaging materials, ensuring the freshness and protection of oxygen-sensitive products immediately after filling.
Implementation Method 1
a non-polymeric oxidizable organic compound... which react with oxygen that is trapped in the package
Implementation Method 2
the catalyst for the oxygen scavenging material is transition metal salts
Data Source
AI summary
The present invention provides a composition comprising: a polyester base polymer; at least one non-polymeric oxidizable organic compound; at least one transition metal in a positive oxidation state, said metal being present in the composition in an amount of from about 10 to about 400 ppm, wherein the polyester base polymer comprises less than about 40 ppm phosphorous. The compositions of the present invention do not exhibit an induction period prior to the onset of oxygen scavenging upon formation into a container.