Fiber-Reinforced Resin Laminate with Segmented Prepreg
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Solution Overview
Problem
Existing fiber-reinforced resin technologies face challenges in achieving a balance between excellent mechanical characteristics, shapeability into complicated shapes, and cost-effectiveness, with prior methods either compromising on mechanical properties or moldability and productivity.
Innovation Solution
A fiber-reinforced resin laminate with a two-layer structure, where layer (A) has high mechanical characteristics and layer (B) offers excellent stamping moldability, is developed, with specific thickness and viscosity ratios, and the use of incisions in layer (A) to enhance fluidity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous reinforcing fibers are used to achieve excellent mechanical properties, then mechanical strength is improved, but fluidity deteriorates making it difficult to form complicated shapes
Solution Approach 1:
The continuous reinforcing fibers are divided into segmented fibers through incisions made at regular intervals across the prepreg width. This segmentation allows the fibers to flow and conform to complicated three-dimensional shapes during stamping molding while maintaining mechanical strength through controlled fiber length (average 10-100mm).
Solution Approach 2:
Incisions are strategically made only in specific regions where shape complexity requires improved fluidity, rather than uniformly across the entire prepreg. This localized approach maintains mechanical strength in areas where continuous fibers are beneficial while enabling shapeability where needed.
2Ease of manufacture
If incisions are inserted into prepreg to improve shapeability, then fluidity is improved, but mechanical characteristics deteriorate
Solution Approach 1:
The incision parameters (depth, spacing, width) are optimized to achieve the right balance. Incisions are made at depths of 1-5mm with spacing of 50-200mm, creating fiber segments of average length 10-100mm. This parameter optimization ensures sufficient fluidity for shapeability while maintaining mechanical strength by not over-cutting the fibers.
3Ease of manufacture
If LFT-D molding is used to achieve complicated shapes, then shapeability is improved, but fiber distribution uniformity deteriorates causing mechanical property variation
Solution Approach 1:
The prepreg is pre-formed with continuous fibers properly aligned and resin-impregnated before molding. Incisions are pre-cut into the prepreg to create controlled fiber segmentation. This preliminary preparation ensures uniform fiber distribution in the final product while enabling complicated shapes, avoiding the random fiber distribution problems of LFT-D.
4Strength
If prepreg with continuous fibers is used to maintain mechanical strength, then structural integrity is improved, but molding cycle time increases
Solution Approach 1:
By segmenting continuous fibers through incisions, the prepreg gains improved fluidity that reduces molding cycle time. The segmented fibers flow more easily into the mold cavity and conform to shapes faster, while the segment length is controlled (10-100mm average) to maintain structural integrity in the final molded part.
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 laminate achieves excellent mechanical characteristics with reduced variation, improved shapeability into complex shapes, and cost-effectiveness, enabling rapid molding while maintaining structural integrity.
Implementation Method 1
heating and pressurizing the fiber-reinforced resin with a press or the like
Implementation Method 2
heating and pressurizing the fiber-reinforced resin with a press or the like
Data Source
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AI summary
Provided is a fiber-reinforced resin laminate that is characterized by: comprising stacked layers of the (A) layer and the (B) layer that are indicated below; and by the value resulting from dividing the sum total of the thickness of the (A) layer by the sum total of the thickness of the (B) layer being 0.5-3.0. (A) layer: a laminate that comprises a prepreg in which reinforcing fibers are impregnated with a resin or a resin composition and wherein the product of the square of the volume fraction (Vf) of the reinforcing fibers and the average fiber length (Lamm) is greater than 2.0 mm and equal to or less than 15 mm. (B) layer: a sheet that comprises at least one composition selected from the group consisting of resin compositions and filler-containing resin compositions and wherein the product of the square of the volume fraction (Vf) of the filler and the average value (Lbmm) of the maximum length of the filler is 2.0 mm or less.