Regenerated Styrene Resin Composition for Impact and Creep Resistance
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Solution Overview
Problem
The challenge lies in developing a regenerated-styrene-based resin composition with a high recycled material content that maintains excellent impact resistance, creep resistance, and compliance with UL94HB flammability standards, while addressing the instability and contamination issues inherent in recycled materials.
Innovation Solution
A composition comprising 40-90% styrene-based recycled material and 10-60% styrene-based virgin material, with specific ranges for rubber-like polymer content, toluene insoluble matter, and trace elements like chlorine and bromine, optimized for impact resistance, creep resistance, and flammability, using a combination of post-consumer recycled materials and virgin styrene-based resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of styrene-based recycled material is increased to 40% or more, then the recycled material content rate is improved, but the physical properties deteriorate due to deterioration, dirt, and foreign substances
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of rubber-like polymer (5.0-7.0% by mass) and limiting toluene insoluble matter (21% by mass or less) in the recycled material. These parameter specifications transform the unstable recycled material into a reliable composition by defining acceptable ranges for deterioration and contamination levels.
Solution Approach 2:
The patent creates a composite material system combining styrene-based recycled material (40-90% by mass) with styrene-based virgin material (10-60% by mass). This composite approach allows the recycled component to provide environmental benefits while the virgin component ensures stable physical properties, resolving the contradiction between high recycled content and property stability.
2Strength
If the content of rubber-like polymer is increased to 5.0% or more, then the impact resistance is improved, but the creep resistance in thin-walled structures may deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely defining the rubber-like polymer content range (5.0-7.0% by mass). This specific parameter optimization balances the competing requirements: enough rubber-like polymer to provide impact resistance through energy absorption, but limited to prevent excessive creep in thin-walled structures under sustained load.
Solution Approach 2:
The patent applies local quality by differentiating the functional requirements for different performance aspects. The rubber-like polymer provides localized impact absorption capability, while the overall composition design (including virgin material content and toluene insoluble matter limits) ensures localized creep resistance in thin-walled areas, allowing different regions of the material system to excel at different functions.
3Reliability
If the content of toluene insoluble matter is reduced to 21% or less, then the purity is improved, but the impact resistance may deteriorate due to reduced rubber-like polymer content
Solution Approach 1:
The patent applies parameter changes by setting the toluene insoluble matter limit (21% by mass or less) in conjunction with the rubber-like polymer content requirement (5.0-7.0% by mass). This dual parameter control ensures that while most insoluble matter (which represents contamination) is removed, sufficient rubber-like polymer remains to provide impact resistance, as genuine rubber content is distinguished from other insoluble contaminants through the polymer content specification.
4Stress or pressure
If the bending strength is increased to 47 MPa or more, then the creep resistance is improved, but the impact resistance may deteriorate due to reduced rubber-like polymer content
Solution Approach 1:
The patent applies parameter changes by establishing the bending strength requirement (47 MPa or more) alongside the rubber-like polymer content specification (5.0-7.0% by mass). This coordinated parameter control ensures that the matrix structure provides sufficient bending strength for creep resistance, while the rubber-like polymer phase maintains adequate impact resistance, preventing the trade-off from occurring.
Data Source
AI summary
Provided are a regenerated-styrene-based resin composition that has a high rate of recycled material content, excellent impact resistance, excellent creep resistance in a thin-walled thickness, as well as a safeness in that the flammability complies with UL94HB, and a molded object including the resin composition.In a regenerated-styrene-based resin composition including a styrene-based recycled material (A) and a styrene-based virgin material (B), the content of the styrene-based recycled material (A) being 40% by mass or more and 90% by mass or less relative to 100% by mass of (A) and (B) in total, the content of a rubber-like polymer is 5.0% by mass or more and 7.0% by mass or less, the content of toluene insoluble matter is 21% by mass or less, and a bending strength, determined in accordance with JIS K7171, is 47 MPa or more.