Automotive Bumper Polymer Composition for Low Shrinkage and High Gloss
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Solution Overview
Problem
The automotive industry seeks a polymer composition for bumpers that balances low shrinkage, high gloss, and high impact resistance, which existing propylene-based polymer compositions have not adequately achieved.
Innovation Solution
A polymer composition comprising a first and second heterophasic propylene copolymer and an ethylene-based elastomer, with specific weight percentages and properties, including MFI ranges and xylene-soluble and insoluble portions, to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a propylene-based polymer composition is used for automotive bumpers, then impact resistance can be maintained, but shrinkage control and gloss quality deteriorate
Solution Approach 1:
The patent employs a composite polymer system consisting of polypropylene resin combined with specific elastomers (ethylene-propylene-diene copolymer and/or polyethylene). This composite material approach allows the bumper composition to achieve simultaneous improvement in impact resistance, shrinkage control, and gloss quality by leveraging the complementary properties of different polymer components rather than relying on propylene-based polymer alone
2Strength
If a propylene-based polymer composition is used for automotive bumpers, then impact resistance can be maintained, but gloss quality deteriorates
Solution Approach 1:
The composite polymer system comprising polypropylene resin with controlled elastomer content (5-20 parts by weight per 100 parts resin) creates a material that simultaneously achieves high impact resistance and superior gloss quality. The specific elastomer types and their controlled proportions are critical to achieving both mechanical strength and surface optical properties
3Strength
If elastomer content is increased to improve impact resistance, then impact resistance improves, but shrinkage control deteriorates
Solution Approach 1:
The patent precisely controls the elastomer content parameter within the range of 5-20 parts by weight per 100 parts of polypropylene resin. This parameter optimization ensures that impact resistance is sufficiently enhanced while maintaining shrinkage control below 0.93%. The specific elastomer types (ethylene-propylene-diene copolymer and/or polyethylene) are also carefully selected to achieve the desired balance between these properties
Data Source
AI summary
A polymer composition contains a first heterophasic propylene copolymer, a second heterophasic propylene copolymer and an ethylene based elastomer. A process for the preparation of the polymer composition is also disclosed. An automotive part includes such polymer composition. The polymer composition has high gloss, low shrinkage and high impact resistance