Polyolefin Composition Chlorine Dioxide Degradation Resistance
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Solution Overview
Problem
Polyolefin materials used in water distribution systems are prone to degradation from chlorine dioxide-containing water, leading to reduced lifespan and potential health risks due to inadequate antioxidant resistance, and existing antioxidants do not effectively prevent degradation without contaminating the water supply.
Innovation Solution
A polyolefin composition combining specific antioxidants with high and low initial oxygen induction times (OIT) at 190°C, along with an additional antioxidant, to enhance stability and resistance to chlorine dioxide, characterized by a specific degradation velocity and half-life depletion velocity in chlorine dioxide-containing water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher concentrations of antioxidants are added to increase resistance against chlorine dioxide, then degradation protection is improved, but extraction of antioxidants into water supply increases
Solution Approach 1:
The patent optimizes the concentration parameters of each antioxidant component to achieve effective protection at minimal levels. The specific combination of Irganox 1010, Irganox 1330, and vitamin E provides synergistic effects that maximize protection efficiency while minimizing total antioxidant content, thereby reducing extraction into water supply.
Solution Approach 2:
The patent employs antioxidants with different service lifetimes and degradation rates. Irganox 1330 provides rapid initial protection and depletes quickly, while Irganox 1010 provides long-term stability. This tiered approach ensures adequate protection during critical early exposure periods while minimizing long-term antioxidant presence in the water supply.
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 combination of antioxidants significantly increases the polyolefin composition's resistance to chlorine dioxide, extending the degradation time and maintaining the integrity of the material in contact with chlorine dioxide-containing water, while minimizing antioxidant extraction into the water supply.
Implementation Method 1
Polymeric compounds are prone to aging under the effects of oxidants, light and heat. It is well-known in the art that antioxidants and light stabilizers can prevent or at least reduce these effects.
Implementation Method 2
antioxidants (B) and (C) in a specific combination to protect the polyolefin base resin from degradation by chlorine dioxide-containing water
Implementation Method 3
Polyolefin resins have shown to have a lower lifetime in chlorine dioxide containing water than in chlorine containing water. Thus, chlorine-resistant polyolefin resins may not be resistant against chlorine dioxide.
Data Source
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AI summary
The present invention relates to a polyolefin composition with increased resistance to degradation caused by ClO2-containing water and to an article made of such a polyolefin composition. The polyolefin composition comprises a polyolefin base resin (A), at least one antioxidant (B) having an initial oxygen induction time (OIT190°C) of more than 35 min., determined according to the OIT190°C test described herein and having a slope of the curve, when OIT190°C, in minutes, is recorded as a function of exposure time, in minutes, in a chlorine dioxide degradation test as described herein, of at least -0.07, and c) at least one antioxidant (C) having an initial oxygen induction time (OIT190°C) of not more than 35 min., determined according to the OIT190°C test described herein and having a slope of the curve, when OIT190°C, in minutes, is recorded as a function of exposure time, in minutes, in a chlorine dioxide degradation test as described herein, of less than -0.07, wherein said polyolefin composition shows a resistance against water containing 10 ppm chlorine dioxide at 70 °C and a pH of 6.8 ± 0.1 of at least 450 min., expressed as the time to reach 50% of the initial oxygen induction time at 210 °C (OIT(210°C),50%), determined according to the chlorine dioxide degradation test as described herein. The present invention further relates to the use of the polyolefin composition for the production of an article, e.g. a pipe, a fitting or a storage container and to the use of the polyolefin composition for increasing the resistance of an article against degradation caused by contact with ClO2-containing water.