Blow Molded ABS Resin Composition for Automotive Spoilers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing thermoplastic resin compositions for blow molding, particularly ABS resins used in automotive spoilers, face challenges with low melt viscosity leading to parison sag and uneven thickness, reduced impact strength, and increased probability of crack defects due to environmental stress-cracking resistance degradation during painting, especially when high molecular weight SAN resins are used.
Innovation Solution
A thermoplastic resin composition comprising 25-50% graft copolymer resin of a vinyl cyanide compound-rubbery polymer-aromatic vinyl compound and 30-75% α-methylstyrene-based heat-resistant resin with a glass transition temperature of 125°C or more, along with optional α-methylstyrene-based bulk polymerized SAN and N-phenylmaleimide-based polymer to balance melt viscosity, impact resistance, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bulk polymerized heat-resistant SAN resin with weight average molecular weight of 80,000 to 200,000 is used for blow molding, then the resin can be processed, but parison sag occurs during parison formation and uneven wall thickness results
Solution Approach 1:
The patent changes the molecular weight parameter of the SAN resin to 200,000 or more, which fundamentally alters the melt viscosity characteristics. This parameter change enables the resin to maintain adequate viscosity during parison formation, preventing sag while allowing continued processability through blow molding
Solution Approach 2:
The patent creates a composite resin system by combining bulk polymerized SAN resin (with specific high molecular weight characteristics) and emulsion polymerized ABS resin. This composite approach balances the competing requirements of processability and dimensional stability, achieving both ease of manufacture and manufacturing precision
2Reliability
If high molecular weight SAN resin is used to improve chemical resistance, then environmental stress-cracking resistance improves, but melt viscosity increases causing parison sag
Solution Approach 1:
The patent precisely controls the molecular weight parameter at 200,000 or more, which provides sufficient chemical resistance while managing melt viscosity. This specific parameter threshold achieves the balance between reliability and preventing harmful effects
Solution Approach 2:
By formulating a composite of bulk polymerized SAN resin and emulsion polymerized ABS resin, the patent distributes the functional requirements: the SAN component provides chemical resistance through high molecular weight, while the ABS component contributes to processability and overall structural integrity
3Strength
If emulsion polymerized ABS resin is used for blow molding, then impact strength is maintained, but melt viscosity is too low causing uneven wall thickness
Solution Approach 1:
The patent creates a synergistic composite material system where emulsion polymerized ABS resin (providing impact strength) is combined with bulk polymerized SAN resin (providing appropriate melt viscosity). The composite achieves both the mechanical strength requirement and the dimensional control requirement during blow molding
Solution Approach 2:
The patent merges two different resin systems with complementary properties into a single formulation. The emulsion polymerized ABS contributes toughness and impact resistance, while the bulk polymerized SAN contributes viscosity control and dimensional stability, achieving a unified material that satisfies multiple competing requirements
Data Source
AI summary
The present invention relates to a thermoplastic resin composition with excellent chemical resistance and, more specifically, to a resin composition for blow molding and a molded product obtained by molding the same, the composition maintaining the balance of flowability and impact resistance and improving chemical resistance by controlling the glass transition temperature (Tg) and the weight average molecular weight (Mw) of an α-methylstyrene (AMS)-based heat-resistant resin in a copolymer of vinyl cyanide compound-rubbery polymer-aromatic vinyl compound, having reinforced heat resistance, particularly, in an acrylonitrile-butadiene-styrene (ABS) copolymer resin. According to the present invention, an ABS resin composition for blow molding, having excellent chemical resistance while maintaining the balance of flowability, impact resistance and heat resistance to be of at least the same level, and a molded product obtained by applying the same can be obtained.