Aramid Circuit Board Nonwoven Structure for Thin, Smooth Prepregs
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Solution Overview
Problem
Conventional circuit board nonwoven fabrics produced with fine denier aramid fibers or only flattened short aramid fibers face issues of high cost, reduced strength, and poor yield due to fiber detachment during wet papermaking, leading to increased costs and thickness in circuit boards.
Innovation Solution
A circuit board nonwoven fabric comprising a combination of thick and fine aramid fibers, where thick fibers have a flat shape with a major and minor axis, the minor axis oriented in the thickness direction, and the number of fine fibers exceeds thick fibers, is used to improve smoothness and strength while reducing thickness and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If only fine denier aramid fibers with diameter of 10 μm or less are used to produce circuit board nonwoven fabric, then surface smoothness is improved, but production cost increases and fiber strength decreases
Solution Approach 1:
The patent applies local quality by using different fiber types in different proportions within the nonwoven fabric. Specifically, fine denier aramid fibers (diameter ≤10 μm) are used at 70-90 mass% to ensure surface smoothness, while coarse denier aramid fibers (diameter >10 μm) are used at 10-30 mass% to provide strength and reduce cost. This localized differentiation of fiber properties resolves the contradiction between smoothness and cost-effectiveness.
Solution Approach 2:
The patent employs composite materials by combining two types of aramid fibers with different properties into a single nonwoven fabric structure. The fine denier fibers contribute to surface smoothness while the coarse denier fibers contribute to tensile strength and cost efficiency. This composite approach allows the material to simultaneously achieve smoothness and structural integrity without relying solely on expensive fine fibers.
2Manufacturing precision
If only fine denier aramid fibers are used, then surface smoothness is improved, but the amount of resin required increases leading to increased thickness
Solution Approach 1:
The patent uses local quality by strategically distributing different fiber types to perform different functions. Coarse denier fibers, being stronger and more rigid, provide structural support that reduces the need for excessive resin to maintain strength. Fine denier fibers are concentrated at the surface to ensure smoothness. This functional differentiation allows reduced resin content while maintaining both smoothness and strength, thereby reducing prepreg thickness.
3Length of stationary object
If only flattened short aramid fibers are used to thin the nonwoven fabric, then thickness is reduced, but fiber detachment during wet papermaking increases leading to poor yield
Solution Approach 1:
The patent applies parameter changes by carefully controlling the fiber length parameter. Instead of using only short fibers to reduce thickness, the patent specifies that the average fiber length should be 3-10 mm. This optimized length parameter prevents excessive fiber detachment during wet papermaking while still allowing the fabric to be made thin through controlled basis weight and fiber orientation, thus resolving the contradiction between thickness reduction and production yield.
4Length of stationary object
If the nonwoven fabric is made thinner by using fine fibers, then circuit board thickness is reduced, but production cost increases
Solution Approach 1:
The patent employs composite materials to achieve thinness without excessive cost. By combining fine denier aramid fibers (≤10 μm diameter) at 70-90 mass% with coarse denier aramid fibers (>10 μm diameter) at 10-30 mass%, the nonwoven fabric achieves the required thinness through optimized fiber composition rather than solely relying on expensive fine fibers. The coarse fibers provide structural support that reduces the total fiber content needed, thereby reducing both thickness and cost.
Data Source
AI summary
A circuit board nonwoven fabric comprising a paper-formed structure which comprises a plurality of thick fibers in which the portion of greatest fiber diameter is 5 μm or greater, and a plurality of fine fibers in which the portion of greatest fiber diameter is less than 5 μm, wherein an average fiber length of the thick fibers is greater than an average fiber length of the fine fibers, the number of fine fibers is greater than the number of thick fibers, and the thick fibers have a flat shape with a major axis and a minor axis, the minor axis being oriented in a thickness direction of the paper-formed structure.