Dry Fibrous Reinforcement with Segmented Adhesive Interlay
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Solution Overview
Problem
Current dry fibrous reinforcements face challenges with uneven thickness and low resin permeability due to the use of weft or adhesive filaments for fiber fixation, and pre-impregnated reinforcements are not suitable for interweaving and are costly due to limited availability and high processing complexity of low-count yarns.
Innovation Solution
A dry fibrous reinforcement is manufactured using yarns with a count of 12k or more, featuring two unidirectional skins interconnected by a finely distributed hot-melt thermoplastic adhesive interlay, allowing for uniform fiber distribution and high resin permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a weft filament or adhesive filament is used to fix the fibers, then the fibers are retained in position, but unevenness in the thickness of the reinforcement is generated
Solution Approach 1:
The continuous adhesive filament is segmented into discrete adhesive spots distributed across the reinforcement. This segmentation eliminates the thickness unevenness caused by continuous filaments while still providing effective fiber retention at multiple locations. The adhesive spots are spaced apart, allowing the fibers to be fixed without creating localized thick regions.
Solution Approach 2:
Instead of uniformly distributing adhesive throughout the reinforcement, the invention applies adhesive locally at specific spots. This local quality approach ensures that fiber retention is achieved only where needed, maintaining thickness uniformity in other areas. The adhesive spots are strategically positioned to provide sufficient fiber fixation without compromising overall uniformity.
2Manufacturing precision
If a film of adhesive is applied to fix the fibers, then thickness uniformity is maintained, but the reinforcement becomes less permeable to resins
Solution Approach 1:
The continuous adhesive layer is segmented into discrete spots, creating gaps between adhesive regions. These gaps maintain resin permeability by allowing resin to flow through the reinforcement, while the adhesive spots provide sufficient fiber retention. The segmented structure prevents the complete blockage of resin pathways that occurs with continuous adhesive films.
Solution Approach 2:
The adhesive spots create a porous or discontinuous structure rather than a solid continuous film. This porous arrangement allows resin to penetrate and flow through the reinforcement effectively, while still providing the necessary adhesive bonding to retain fibers. The spaces between adhesive spots function as permeable pathways for resin.
3Weight of stationary object
If yarns with low count are used to achieve low weight per unit surface, then weight is reduced, but fiber distribution uniformity deteriorates
Solution Approach 1:
The adhesive spots act as an intermediary mechanism to achieve uniform fiber distribution without requiring low-count yarns. The adhesive spots provide the necessary binding force to maintain fiber arrangement, replacing the need for numerous closely-spaced yarns. This intermediary approach allows the use of higher count yarns (12k or more) while still achieving uniform distribution at lower weights.
Solution Approach 2:
The invention changes the parameter of yarn count from low (1k-6k) to high (12k or more), and compensates for the weight increase by reducing the overall yarn density and using adhesive spots for retention. This parameter change allows using more readily available, cost-effective yarns while maintaining uniform fiber distribution through the adhesive spot mechanism.
4Ease of manufacture
If yarns with high count are used, then availability and cost improve, but the resulting reinforcement has higher weight per unit surface
Solution Approach 1:
The invention extracts the fiber retention function from the yarn structure itself and transfers it to separate adhesive spots. This extraction allows the yarns to be used purely for providing fibers, without needing to承担 the additional weight of retention mechanisms. The adhesive spots take over the retention function, enabling the use of high-count yarns without excessive weight increase.
Solution Approach 2:
The invention changes the yarn count parameter from low (1k-6k) to high (12k or more), improving availability and reducing cost. The weight per unit surface is controlled by adjusting the density and distribution of adhesive spots, balancing the weight increase from higher count yarns with efficient adhesive placement.
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
This approach enables the production of dry reinforcements with lower fiber counts, achieving weights as low as 70 g/m² while maintaining uniformity and resin permeability, and is cost-effective and simple to manufacture.
Implementation Method 1
two unidirectional skins interconnected by a finely distributed hot-melt thermoplastic adhesive interlay
Data Source
AI summary
A fibrous reinforcement (10), such as a reinforcement for composite material, which comprises at least two skins (11) of fibers (12) which are interconnected by an adhesive interlay (13), each skin comprising fibers (12) arranged substantially unidirectionally.