Oxygen-absorbing resin composition for packaging
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Solution Overview
Problem
Current oxygen-absorbing resin compositions for packaging materials face challenges such as odor generation during oxygen absorption, insufficient initial oxygen absorption rates, and stability issues during melt-molding, while also requiring enhanced oxygen absorbency and transparency for food and cosmetic packaging.
Innovation Solution
A thermoplastic resin composition with a structural unit containing carbon-carbon double bonds in the main chain, combined with a transition metal salt and a gas barrier resin, dispersed in a matrix resin to achieve high oxygen absorption rates and transparency, while preventing odor generation and maintaining stability during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of carbon-carbon double bonds is increased to enhance oxygen absorbency, then oxygen absorption amount is improved, but stability during melt-molding deteriorates and materials are likely to be colored or generate aggregation
Solution Approach 1:
The patent optimizes the carbon-carbon double bond content within a specific range (0.003 to 0.015 mol/g) rather than maximizing it, and adjusts the allylic position density to achieve the right balance between oxygen absorption capacity and melt-molding stability, preventing excessive oxidation and aggregation
Solution Approach 2:
The invention creates a composite resin system combining multiple polymers (polyester, polyolefin, polyamide) with controlled double bond content and allylic positions, where each component contributes differently to oxygen absorption and processing stability, achieving synergistic effects
2Productivity
If the dispersion of oxygen-absorbing resin composition is enhanced by adding compatibilizer to increase initial oxygen absorption rate, then oxygen absorption rate is improved, but transparency deteriorates
Solution Approach 1:
The patent optimizes the particle size of dispersed oxygen-absorbing resin composition to a specific range (1-10 μm average diameter) and controls the compatibilizer content within precise limits (0.1-5 wt%), achieving both enhanced dispersion for fast initial absorption and sufficient transparency by preventing excessive light scattering
3Reliability
If oxygen absorbent is blended in packaging material to reduce gas transmission, then oxygen barrier properties are improved, but unpleasant odor is generated during oxygen absorption
Solution Approach 1:
The patent carefully controls the carbon-carbon double bond content (0.003 to 0.015 mol/g) and allylic position density within specific ranges, preventing excessive oxidation that leads to odor generation while maintaining effective oxygen absorption capacity and barrier properties
Solution Approach 2:
The invention places oxygen-absorbing functional groups (carbon-carbon double bonds and allylic positions) strategically within the polymer structure at controlled densities, creating localized reactive sites that absorb oxygen efficiently without generating harmful byproducts throughout the entire material
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 composition exhibits excellent oxygen absorbency, high initial oxygen absorption rates, and transparency, effectively extending the shelf life of packaged products by preventing oxygen degradation without generating unpleasant odors, and is suitable for packaging sensitive materials like food and cosmetics.
Implementation Method 1
a composition containing an ethylenically unsaturated hydrocarbon and a transition metal catalyst has been proposed... resin compositions containing EVOH and an oxygen absorbent... the oxygen absorbent is decomposed as oxygen absorption proceeds
Implementation Method 2
a composition containing an ethylenically unsaturated hydrocarbon and a transition metal catalyst has been proposed... containing a transition metal salt and a thermoplastic resin having carbon-carbon double bonds
Data Source
Figure 1~2
Figure 3
AI summary
It is an object of the invention to provide an oxygen-absorbing resin composition that has excellent oxygen absorbency, in particular a high initial oxygen absorption rate, does not generate an unpleasant odor as a result of oxygen absorption and has high transparency. This objective is achieved by providing an oxygen-absorbing resin composition containing a thermoplastic resin (A) having the structural unit represented by formula (1) below, a transition metal salt (B) and, as necessary, a matrix resin (C): wherein R1 and R2 are as defined in the specification.