Fiber Tow Coating Rollers for Solvent-Free Prepreg Tapes
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Solution Overview
Problem
Current methods for producing prepreg fiber tapes, such as solvent dip and hot melt processes, face issues like residual solvent in the product, high void content, energy consumption, and fiber weakening during the slitting process, making them unsuitable for high-end applications like aerospace.
Innovation Solution
An apparatus with a belt press and matrix application rollers that control the application of a liquid matrix to a fiber tow, reducing the number of process steps and components, eliminating the need for intermediate chilling, and ensuring a consistent resin-to-fiber ratio by adjusting the gaps between the rollers and the belt press, allowing for efficient and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solvent dip process is used to form prepreg, then resin coating is achieved, but residual solvent remains causing high void content and volatile problems
Solution Approach 1:
The patent changes the physical state parameter of the resin from dissolved liquid (solvent-based) to melted solid (solvent-free). By heating the resin above its melting point and controlling cooling rates, the process achieves complete resin impregnation without leaving residual solvents that cause voids and volatiles in the final composite product
Solution Approach 2:
The patent utilizes phase transition of the resin from solid to liquid state through controlled heating and cooling. The resin is heated to melt and flow into the fiber tow, then cooled to solidify and bond the fibers together, eliminating the need for solvent evaporation and associated void formation
2Quantity of substance
If hot melt process with multiple reels is used, then resin impregnation is achieved, but the process becomes complex and time-consuming
Solution Approach 1:
The patent merges multiple separate process stages (resin application, impregnation, and consolidation) into a single integrated belt press operation. The resin-coated belt and fiber tow are fed simultaneously into one press that performs all impregnation and consolidation functions, eliminating the need for multiple reels and sequential processing steps
Solution Approach 2:
The belt press apparatus performs multiple functions simultaneously: it applies resin from the coated belt, transfers resin to the fiber tow, consolidates the impregnated fibers, and controls the resin-to-fiber ratio all in one operation, making the equipment highly versatile and efficient
3Productivity
If wide sheets are used for efficiency, then processing efficiency is improved, but the slitting process weakens fibers at the edges
Solution Approach 1:
The patent segments the resin application process by using a belt that is precisely the width of the desired final product. This eliminates the need to produce wide sheets and slit them later, as each belt width corresponds to a specific tape width, preventing fiber damage at edges while maintaining efficient continuous processing
Solution Approach 2:
The resin is applied to the belt at the precise width required for the final product before the fiber impregnation process begins. This preliminary sizing action prevents the need for subsequent slitting operations that would damage fibers, while still allowing efficient continuous production
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 reduces energy consumption, minimizes waste, and ensures a consistent resin distribution, enhancing the quality of the prepreg fiber tapes by eliminating residual solvents and fiber weakening, making them suitable for high-end applications.
Implementation Method 1
a matrix application roller arranged to receive liquid matrix and transfer it to the fiber tow
Implementation Method 2
a belt press arranged to receive the fiber tow and compress it between two moving belts
Data Source
AI summary
An apparatus for applying a liquid matrix to a fiber tow includes a belt press arranged to receive the fiber tow and compress it between two moving belts and a matrix application roller arranged to receive liquid matrix and transfer it to the fiber. The apparatus also includes a second matrix application component arranged adjacent to the matrix application roller so as to form a first gap between the component and the matrix application roller. The matrix application roller is positioned adjacent to the belt press so as to form a second gap between the matrix application roller and a belt of the belt press; and wherein the second gap is larger than the first gap.