In-line Fiber Sizing for Pultruded Polyurethane Composites
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Solution Overview
Problem
Current pultrusion processes for fiber-reinforced thermoset polyurethane composites require separate fiber sizing, which limits chemistry applications, incurs high capital costs, and is prone to operator errors and contamination, with little control over fiber-matrix interaction.
Innovation Solution
A continuous pultrusion process that simultaneously optimizes fiber sizing by contacting reinforcing fibers with a sizing composition containing polyimine and coating them with a precursor mixture of di- or polyisocyanate and polyol, followed by passing through heating zones to produce a reinforced thermoset polyurethane composite with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate fiber sizing is performed before pultrusion, then fiber surface treatment can be applied, but it limits chemistry applications, incurs high inventory costs, and requires complex part management
Solution Approach 1:
The patent combines the fiber sizing operation with the pultrusion process by integrating a sizing bath into the continuous pultrusion line. Fibers are sized and impregnated with resin in a single continuous operation, eliminating the need for separate sizing steps, inventory management of pre-sized fibers, and complex part number tracking. This merging of operations directly resolves the contradiction by maintaining chemistry flexibility while simplifying logistics and reducing inventory complexity.
Solution Approach 2:
The sizing bath in the pultrusion process serves multiple functions simultaneously: it applies surface treatment to fibers, impregnates fibers with resin, and prepares fibers for composite formation. This multi-functional approach eliminates the need for specialized pre-sized fiber inventories for different applications, as the sizing composition can be adjusted in-line to match specific chemistry requirements for different composite applications.
2Adaptability or versatility
If separate fiber sizing is performed, then fiber surface treatment can be applied, but it incurs high capital costs for inventory and maintenance
Solution Approach 1:
The patent extracts the sizing operation from the separate pre-processing stage and integrates it into the pultrusion process itself. By taking out the sizing step from offline operations and incorporating it into the continuous inline process, the system eliminates the need to maintain inventories of pre-sized fibers. The sizing composition is applied fresh in-line, removing the burden of inventory storage, handling, and associated capital costs while preserving the ability to apply appropriate surface treatments.
3Adaptability or versatility
If separate fiber sizing is performed, then fiber surface treatment can be applied, but it is prone to operator errors and contamination
Solution Approach 1:
The patent implements continuous in-line sizing within the pultrusion process, where fibers move continuously through the sizing bath and immediately into the impregnation and forming stages. This continuous operation eliminates interruptions, manual handling, and storage periods where contamination could occur. The seamless transition from sizing to composite formation ensures consistent application of surface treatment and resin, reducing operator errors and maintaining process reliability.
Solution Approach 2:
The sizing is performed as a preliminary action directly within the pultrusion line, immediately before fiber impregnation and composite formation. By performing sizing in-line and in sequence with subsequent operations, the system ensures that fibers receive surface treatment under controlled conditions just before use, minimizing exposure to contamination sources and ensuring consistent, reliable application without manual intervention errors.
4Adaptability or versatility
If separate fiber sizing is performed, then fiber surface treatment can be applied, but there is little opportunity to control or optimize fiber-matrix interaction
Solution Approach 1:
The patent merges the sizing and impregnation operations into a single integrated process sequence within the pultrusion line. Fibers are sized and then immediately impregnated with resin in continuous succession without interruption or storage. This merging allows precise control over the timing and conditions of fiber-matrix interaction, as the transition from sized fiber to resin-impregnated composite occurs in a controlled, continuous manner, optimizing interfacial bonding and eliminating variability introduced by separate handling steps.
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 process enhances mechanical properties such as strength and energy absorption, reduces inventory costs, minimizes operator errors, and prevents contamination, while allowing for tailored fiber-matrix interaction and improved composite performance.
Implementation Method 1
contacting a plurality of reinforcing fibers with a sizing composition comprising at least one sizing agent selected from at least one polyimine
Implementation Method 2
passing the plurality of coated sized reinforcing fibers obtained in step (b) through at least one die and at least one heating zone to obtain the reinforced thermoset polyurethane composite
Data Source
AI summary
The present disclosure relates to a pultrusion process for preparing a reinforced thermoset polyurethane composite, and specifically relates to a pultrusion process for simultaneous optimization of fiber sizing continuously along with the pultrusion process without any interruption by contacting the fibers with a sizing composition.