Polyamide Resin Composition for Water-Resistant Molded Products
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Solution Overview
Problem
Polyamide materials suffer from degradation of physical properties due to water absorption, and long fiber-reinforced polyamide compositions exhibit poor appearance in injection-molded products despite excellent mechanical properties.
Innovation Solution
A resin composition comprising 90-50% of polyamide with 7+ carbon atoms and no aromatic rings, 10-50% of crystalline aromatic polyamide, and 5-75 parts by weight of carbon fibers, along with a phenol polymer, which maintains moldability and appearance while minimizing rigidity and strength loss upon water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If long fiber-reinforced polyamide composition is used to enhance mechanical strength, then mechanical properties are improved, but appearance of injection-molded product deteriorates with protruding welding parts
Solution Approach 1:
The patent changes the physical and chemical parameters of the polyamide system by introducing a specific blend ratio of polyamide 610/612 (90-50% weight ratio) with crystalline aromatic polyamide. This parameter change modifies the melting behavior and flow characteristics of the resin, enabling better mold filling and reduced welding part protrusion while maintaining mechanical strength enhancement from carbon fiber reinforcement.
Solution Approach 2:
The patent creates a composite material system combining polyamide 610/612 blend with crystalline aromatic polyamide and carbon fibers (5-75 parts by weight per 100 parts polyamide). This composite approach synergistically combines the high strength of carbon fibers with the improved moldability of the specific polyamide blend, achieving both enhanced mechanical properties and improved appearance.
2Strength
If polyamide material is used for its mechanical properties, then strength is improved, but physical properties degrade due to water absorption
Solution Approach 1:
The patent changes the chemical composition parameters by selecting polyamide 610 and 612 with 7 or more average carbon atoms per amide group and no aromatic rings, blended with crystalline aromatic polyamide. This specific compositional parameter change reduces the material's affinity for water while maintaining mechanical strength, thereby improving reliability in humid or wet environments.
3Shape
If conventional polyamide composition is used to achieve good appearance, then appearance is improved, but moldability deteriorates
Solution Approach 1:
The patent changes the rheological parameters of the polyamide system by using a blend of polyamide 610/612 with crystalline aromatic polyamide. This parameter change optimizes the viscosity and flow characteristics during injection molding, enabling both good appearance with reduced welding part protrusion and excellent moldability for complex geometries.
Data Source
AI summary
A resin composition includes 90 to 50% by weight of (A) a polyamide having 7 or more average carbon atoms per amide functional group and containing no aromatic ring; 10 to 50% by weight of (B) a polyamide having an aromatic ring and being crystalline, based on 100% by weight of the total of the component (A) and the component (B); and 5 to 75 parts by weight of (C) a carbon fiber, based on 100 parts by weight of the polyamide including (A) and (B).