Unidirectional Prepreg Fiber Layout for Strength and Moldability
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Solution Overview
Problem
Existing fiber-reinforced thermoplastic resin sheets face challenges in achieving both high strength and moldability due to gaps (voids) not impregnated with matrix resin and excessive local fiber orientation, which hinders stress transmission and reduces the utilization of fiber strength.
Innovation Solution
A unidirectional prepreg comprising spread reinforcement fibers and a polymer of a bisphenol A type epoxy compound with a weight-average molecular weight of 5,000 to 25,000, and a bisphenol compound, ensuring an average content number of reinforcement fibers in the thickness direction of ten or less, along with a specific average content density and coefficient of variation, to enhance impregnation and fiber alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thick reinforcement fiber bundle is used, then productivity is improved, but manufacturing precision deteriorates due to excessive local fiber orientation and poor impregnation
Solution Approach 1:
The invention divides a thick reinforcement fiber bundle into multiple thin bundles, each containing 10 or fewer reinforcement fibers. This segmentation allows for uniform fiber orientation and complete impregnation while maintaining high productivity through the use of multiple thin bundles instead of one thick bundle.
2Strength
If reinforcement fibers are densely packed, then strength is improved, but moldability deteriorates due to gaps and poor impregnation
Solution Approach 1:
The invention applies local quality by ensuring that each thin bundle contains a specific number of reinforcement fibers (10 or fewer) to achieve optimal local impregnation quality. This allows the resin to completely penetrate between fibers in each bundle while maintaining high fiber strength utilization through proper local fiber distribution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a fiber-reinforced thermoplastic resin sheet with improved moldability and strength, minimizing voids and ensuring uniform fiber impregnation, thereby enhancing the quality of the molded body.
Implementation Method 1
a unidirectional prepreg comprising spread reinforcement fibers and a polymer of a bisphenol A type epoxy compound... ensuring an average content number of reinforcement fibers in the thickness direction of ten or less, along with a specific average content density... to enhance impregnation and fiber alignment
Data Source
AI summary
The present invention provides a fiber-reinforced thermoplastic resin sheet having both high strength and moldability, to provide a unidirectional prepreg from which such a fiber-reinforced thermoplastic resin sheet can be acquired, and to provide a manufacturing method of a unidirectional prepreg. The present invention relates to a unidirectional prepreg having a tape shape comprising: spread reinforcement fibers; and a polymer of a bisphenol A type epoxy compound represented by Formula (1):[where n is an integer of 1 to 4] and a bisphenol compound selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E, and bisphenol P, wherein the polymer has a weight-average molecular weight of 5,000 to 25,000, and wherein the average content number of the reinforcement fibers in a thickness direction of the unidirectional prepreg is ten or less.