Epoxy-Impregnated Yarn for Flexible Composite Preforms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing fiber-reinforced plastic components using prepregs face limitations such as flexural rigidity, limited shelf life, and difficulty in applying around curved or contoured geometries due to the presence of matrix resin, leading to issues with slip resistance and material wastage during perforation production.
Innovation Solution
A yarn comprising reinforcing fiber filaments with a resin infiltrated at 2.5 to 25 wt.% of a mixture of epoxy resins, allowing the filaments to be bound and repeatedly melted and solidified, which can be stored and processed without additional binder material, maintaining textile properties and preventing material wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If prepregs (preimpregnated fibers with matrix resin) are used, then the material already contains both components in the correct ratio, but the material becomes resistant to bending and has limited shelf life
Solution Approach 1:
The invention extracts the matrix resin from the fiber bundle, creating a core-shell structure where the resin is confined to the outer shell rather than being impregnated throughout the fibers. This separation allows the fiber core to remain flexible and extends shelf life while maintaining the ability to form a complete composite structure during processing.
Solution Approach 2:
The composite material is segmented into distinct functional zones: a flexible fiber core containing no or minimal resin, and an outer shell containing the matrix resin. This segmentation allows each component to perform its optimal function - the core provides flexibility and structural integrity, while the shell provides the matrix functionality.
2Stability of the object's composition
If prepregs with matrix resin are used, then the components are in correct ratio, but the material cannot be processed around narrow radii or on strongly contoured geometries
Solution Approach 1:
By extracting the matrix resin from the fiber interior and confining it to the outer shell, the invention creates a flexible core that can be easily manipulated around narrow radii and complex geometries. The resin shell is applied after the fiber architecture is established, allowing geometric adaptability without compromising component ratio.
Solution Approach 2:
The fiber bundle is prepared in advance with the correct fiber architecture and composition, but the matrix resin application is deferred until the fiber structure is finalized. This preliminary preparation of the fiber core allows for easy manipulation and geometric adaptation before the resin is applied in the final configuration.
3Shape
If textile flat structures with binder coating are used, then the structure can be formed, but the binder coating is unevenly distributed and slip resistance is low
Solution Approach 1:
The invention removes the binder coating application step by confining the matrix resin to the outer shell of the fiber bundle. This eliminates the problem of uneven binder distribution and low slip resistance, as the resin is applied in a controlled manner on the exterior surface rather than attempting to coat the interior of the textile structure.
Solution Approach 2:
Instead of applying binder to the surface of a formed textile structure (outside-in approach), the invention applies the matrix resin to the exterior shell of the fiber bundle after the fiber architecture is established. This inverted approach ensures uniform resin distribution and maintains surface friction properties.
4Shape
If textile flat structures are used for preforms, then the structure can be formed, but additional processing time and material wastage occur during perforation
Solution Approach 1:
The fiber bundle is prepared in advance with the correct architecture, composition, and any required perforations or geometric features before the matrix resin is applied. This preliminary formation of the complete fiber structure eliminates the need for subsequent cutting and perforation operations that cause material wastage and reduce productivity.
Solution Approach 2:
By separating the fiber structure formation from the resin application, the invention allows the fiber core to be manufactured with precise geometry and perforations without the constraints of having resin already present. This extraction of the resin application step enables more efficient preform production with reduced material wastage.
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 yarn enables the production of preforms with improved shelf life, slip resistance, and reduced material waste, allowing for easier handling and processing into composite materials with tailored mechanical properties.
Implementation Method 1
a resin which is infiltrated into the yarn and can be repeatedly melted and solidified by cooling to room temperature
Data Source
AI summary
A yarn includes reinforcing fiber filaments and a resin that is infiltrated into the yarn and can be repeatedly melted and solidified by cooling to room temperature, wherein the filaments of the yarn are at least partially bound to one another by the resin, wherein the yarn contains 2.5 to 25 wt.% of infiltrated resin relative to its total weight, and wherein the infiltrated resin includes a mixture of at least two epoxy resins E1 and E2, E1 having an epoxy value in the range of 2,000 to 2,300 mmol/kg of resin and E2 having an epoxy value in the range of 500 to 650 mmol/kg of resin, and the weight ratio E1:E2 of the epoxy resins E1 and E2 in the mixture is chosen so that the infiltrated resin mixture has an epoxy value between 550 and 2,100 mmol/kg of resin. A preform comprising the yarn, a method for producing the preform and its use in producing a composite are also described.