Moving Pressure Nip Impregnation for Prepreg Production
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional prepreg fabrication methods using static pressure nips are limited by low production speeds due to the physical constraints of Darcy's law, which restricts the impregnation rate and is prone to premature curing or insufficient resin penetration, especially when dealing with carbon fiber webs.
Innovation Solution
The Relative Speed Impregnation (RSI) technique involves moving a continuous fibrous web through an impregnation zone with a moving pressure nip, decoupling the impregnation process from the web's line speed by applying pressure-at-time, allowing for higher production rates with minimal fiber bed distortion and optimal impregnation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static pressure nips are used for impregnation, then resin penetration into fiber web is achieved, but production speed is limited to low rates
Solution Approach 1:
The patent transitions from static pressure nips to a dynamic pressure application system where pressure is applied at multiple points along the impregnation zone. The pressure distribution is dynamically controlled to maintain optimal pressure-at-time throughout the fiber web thickness, enabling high production speeds while preserving precise impregnation control.
Solution Approach 2:
The patent changes the pressure application parameters from a single static pressure point to multiple pressure points distributed along the impregnation zone. This parameter change allows the system to maintain effective pressure control during high-speed operation, resolving the contradiction between production speed and impregnation precision.
2Productivity
If higher temperatures are applied to increase resin flow, then impregnation rate improves, but premature curing or swelling occurs
Solution Approach 1:
The patent segments the impregnation process into multiple zones with different pressure applications, allowing controlled resin penetration without requiring excessive temperature. This segmentation enables the resin to flow adequately through the fiber web while maintaining temperature control to prevent premature curing or swelling.
Solution Approach 2:
The patent introduces pressure-at-time as an intermediary mechanism to control resin flow instead of relying solely on temperature. By applying pressure at multiple points along the impregnation zone, the system mediates between the need for adequate resin flow and the need to maintain resin quality, preventing premature curing while achieving high impregnation rates.
3Productivity
If web speed is increased to improve productivity, then production rate increases, but resin penetration into fiber web becomes insufficient
Solution Approach 1:
The patent implements a dynamic pressure application system with multiple pressure points distributed along the impregnation zone. This dynamic approach maintains adequate pressure-at-time even at high web speeds, ensuring sufficient resin penetration while achieving high production rates that would be impossible with static pressure nips.
4Manufacturing precision
If pressure is increased to improve resin penetration, then impregnation level improves, but fiber bed distortion increases
Solution Approach 1:
The patent segments the pressure application into multiple distributed points along the impregnation zone rather than applying high pressure at a single point. This segmentation achieves adequate impregnation levels through distributed pressure control while minimizing localized compression that would cause fiber bed distortion.
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
RSI significantly increases prepreg production speed while maintaining control over impregnation levels, achieving up to 10-fold higher line speeds compared to conventional methods, with the ability to apply optimal pressure over time without causing resin distortion or premature curing.
Implementation Method 1
the fundamental physical limitations outlined in Darcy's law: the rate of fluid flow is a function of the pressure supplied, the thickness of the body, the permeability of the body of interest and the viscosity of the fluid
Implementation Method 2
The resulting prepregs produced from the prepreg fabrication process is in an uncured or curable state (i.e., not hardened) and may be frozen in order to inhibit the polymerization of the resin
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A method for impregnating a fibrous material with a curable resin to form a prepreg (22) is disclosed. The method includes conveying a web material through at least one moving pressure nip formed between a moving pressure roller (54) and a moving supporting surface, wherein the moving pressure roller (54) and the moving supporting surface travel at different velocities relative to each other resulting in a relative velocity (vre|) between the web material and the pressure nip. The at least one moving pressure nip travels in the same direction as the web material while applying sufficient pressure to compress the web material and to affect impregnation of the fibrous material with the curable resin. Also disclosed is a system for implementing the disclosed impregnation method.