Propylene Terpolymer Containers Impact Haze Balance
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Solution Overview
Problem
Existing containers for food made from propylene/ethylene/1-hexene terpolymers lack a balanced combination of mechanical and optical properties, such as impact resistance, low haze, and hexane extractables, which are critical for food storage.
Innovation Solution
A propylene/ethylene/1-hexene terpolymer with specific composition ranges (ethylene 0.6-1.1 wt%, 1-hexene 1.1-2.8 wt%, and a C2/C6 ratio of 0.20-0.39, along with a controlled melt flow rate and stereoregularity, is used to create injection molded containers with improved mechanical and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If propylene/ethylene/1-hexene terpolymer is used for container production, then mechanical properties such as impact resistance are improved, but optical properties such as haze and hexane extractables are worsened
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition parameters of the terpolymer: ethylene content (0.6-1.1 wt%), 1-hexene content (1.1-2.8 wt%), and the C2/C6 ratio (0.20-0.39). This specific parameter optimization resolves the contradiction by achieving a balance where the polymer maintains sufficient impact resistance while reducing haze and hexane extractables to acceptable levels for food contact applications
Solution Approach 2:
The patent uses a composite material approach by creating a three-component terpolymer system (propylene/ethylene/1-hexene) rather than using simple propylene homopolymer or binary copolymers. The synergistic combination of three monomers with specific proportions allows simultaneous optimization of mechanical properties (from propylene and ethylene) and optical properties (influenced by 1-hexene content and distribution), thereby resolving the contradiction between impact resistance and optical quality
2Strength
If ethylene content is increased to improve mechanical properties, then impact resistance is improved, but hexane extractables and haze increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ethylene content parameter within a narrow range (0.6-1.1 wt%). This specific parameter optimization resolves the contradiction by achieving sufficient impact resistance from the ethylene component while limiting hexane extractables and haze to acceptable levels, which would not be possible with higher ethylene contents
3Object-affected harmful factors
If 1-hexene content is increased to improve optical properties, then haze is reduced, but mechanical properties deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the 1-hexene content parameter within a specific range (1.1-2.8 wt%). This optimization resolves the contradiction by achieving sufficient optical properties (low haze) while maintaining adequate mechanical properties through the balanced contribution of propylene and ethylene components in the terpolymer system
Data Source
AI summary
A container comprising a propylene, ethylene, 1-hexene terpolymer wherein in the terpolymer: (i) the content of ethylene derived units ranges from 0.6 wt% to 1.1 wt%; (ii) the content of 1-hexene derived units ranges from 1.1 wt% to 2.8 wt%; (iii) the ratio between the ethylene derived units content and the 1-hexene derived units content C2/C6 fulfills the following equation (I); C2/C6< 0.39; wherein C2 is the content of ethylene derived units wt% and C6 is the content of 1-hexene derived units wt%; (iv) the melt flow rate MFR measured according to ISO 1133,230° C, 2.16 kg ranges from 32 to 64 g/10 min.