Fiber-Reinforced Resin Composition for Thin-Wall Injection Molding
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Solution Overview
Problem
Molding materials with reinforcing fibers face challenges in achieving a balance between excellent flowability, mechanical properties, and dimensional accuracy, particularly for small, thin, and complicated molded articles, as long fibers enhance mechanical properties but can break during injection molding, while short fibers improve flowability but reduce mechanical properties and accuracy.
Innovation Solution
A fiber-reinforced resin molding material comprising a combination of long reinforcing fibers aligned in the longitudinal direction and bundled reinforcing fibers, with a core-sheath structure, using a thermoplastic resin, to enhance flowability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If long reinforcing fibers are used to enhance mechanical properties, then strength and dimensional accuracy improve, but flowability deteriorates and fiber breakage occurs during injection molding
Solution Approach 1:
The reinforcing fibers are segmented into two distinct types: long fibers (3-15 mm) for mechanical strength and short bundled fibers (0.5-2.9 mm) for flowability. This segmentation allows each fiber type to perform its optimal function without the drawbacks of the other, resolving the contradiction between strength and flowability.
Solution Approach 2:
The invention creates a composite fiber system combining two different fiber types with complementary properties. The long fibers provide tensile strength and dimensional stability, while the short bundled fibers improve flow characteristics and reduce breakage during molding, achieving a synergistic effect that resolves the technical contradiction.
2Object-generated harmful factors
If short reinforcing fibers are used to improve flowability, then flowability and ease of molding improve, but mechanical properties and dimensional accuracy deteriorate due to fiber breakage
Solution Approach 1:
The fiber system is segmented into short bundled fibers for flowability and long fibers for strength. The short fibers (0.5-2.9 mm) reduce viscosity and improve flow during injection molding, while the long fibers (3-15 mm) maintain mechanical properties, resolving the contradiction between flowability and strength.
Solution Approach 2:
The invention changes the fiber length parameter to create a bimodal distribution. By optimizing the length parameters of both short and long fibers within specific ranges, the material achieves optimal balance between flowability during molding and mechanical properties in the final product.
3Manufacturing precision
If long reinforcing fibers are used to achieve dimensional accuracy, then dimensional accuracy and mechanical properties improve, but moldability and flowability deteriorate
Solution Approach 1:
The fiber population is segmented into long fibers for dimensional accuracy and short bundled fibers for moldability. The long fibers (3-15 mm) maintain structural integrity and dimensional stability, while the short fibers (0.5-2.9 mm) enhance flowability and ease of manufacturing, resolving the contradiction between precision and ease of manufacture.
Solution Approach 2:
The composite fiber system combines fibers with different length characteristics to achieve both high dimensional accuracy and excellent moldability. The synergistic interaction between long and short fibers allows the material to be easily molded while maintaining precise dimensional control in the final product.
Data Source
AI summary
A fiber-reinforced resin molding material comprising reinforcing fibers (A) and a thermoplastic resin (B), wherein the fiber-reinforced resin molding material contains 1 to 30 parts by weight of the reinforcing fibers (A) and 70 to 99 parts by weight of the thermoplastic resin (B) with respect to 100 parts by weight in total of (A) and (B), the reinforcing fibers (A) comprise reinforcing fibers (A-1) and bundled reinforcing fibers (A-2), the reinforcing fibers (A-1) have a length of 3 to 15 mm and are aligned in the longitudinal direction of the molding material, the length of the reinforcing fibers (A-1) is the same as the length in the longitudinal direction of the molding material, and the bundled reinforcing fibers (A-2) are configured from 10 or more single fibers having a length of 0.5 to 2.9 mm.