High fatigue resistance abs
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Solution Overview
Problem
Existing ABS thermoplastic molding compositions lack sufficient fatigue resistance and mechanical properties for applications under cyclic loading conditions, particularly due to the use of acrylate copolymers which compromise impact strength and flow properties.
Innovation Solution
A thermoplastic molding composition comprising 25-45 wt.% of a graft copolymer with a specific particle size distribution of agglomerated butadiene rubber latices and 55-75 wt.% of a styrene-acrylonitrile copolymer, optimized for emulsion polymerization and agglomeration processes, along with optional rubber-free thermoplastic resins, to enhance fatigue resistance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If acrylate copolymer is used for agglomeration, then the ABS molding composition can be manufactured, but the mechanical properties (impact strength and elongation at break) and flow properties deteriorate
Solution Approach 1:
The patent removes the harmful acrylate copolymer from the agglomeration process and replaces it with acetic anhydride, which performs the agglomeration function without compromising the mechanical and flow properties of the ABS molding composition
Solution Approach 2:
The patent uses acetic anhydride as a temporary agglomeration agent that performs its function during processing and then degrades or disappears, leaving no harmful residue in the final product, unlike the acrylate copolymer which remains as a permanent contaminant
2Ease of manufacture
If conventional ABS composition is used, then manufacturing is simple, but fatigue resistance under cyclic loading conditions is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific rubber phases and controlling the acrylonitrile content, which enhances fatigue resistance while maintaining manufacturing simplicity through established processing methods
Solution Approach 2:
The patent creates a composite structure within the ABS composition by combining polystyrene, acrylonitrile-butadiene rubber, and carefully controlled acrylonitrile content, resulting in a material with superior fatigue resistance that retains ease of manufacture
3Ease of manufacture
If rubber latices with wide particle size distribution are used, then agglomeration is easier, but the mechanical properties and flow properties deteriorate
Solution Approach 1:
The patent applies local quality control by using acetic anhydride to create uniform agglomerates with specific surface characteristics, ensuring that the agglomeration occurs at the appropriate locations and scales without creating harmful variations in particle size that would degrade mechanical and flow properties
Data Source
AI summary
Thermoplastic molding composition - having an improved fatigue resistance, balanced mechanical properties and a high ductility for applications demanding high endurance under cyclic loading conditions - comprising 25 to 45 wt.-% ABS graft copolymer (A), consisting of 50.5 to 55 wt.-% of a graft sheath (AN content 30.5 to 34 wt.-%) (A2) and 45 to 49.5 wt.-% of a graft substrate (A1), and 55 to 75 wt.-% SAN copolymer (B) (AN content (30 to 33 wt.-%, melt flow rate 30 to 36 g/10 min (220°C/10 kg)).