Highly-Filled Polyurethane Composites With Fiber Length Control
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Solution Overview
Problem
The increase in reinforcing inorganic fiber content in polyurethane composites leads to increased viscosity and fiber breakage during manufacturing, compromising the reinforcing effect.
Innovation Solution
A composite panel design incorporating a polyurethane composite with a fiber reinforcement and a cementitious material, where the fiber reinforcement is embedded in the polyurethane composite, and a cementitious layer is applied to enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the reinforcing inorganic fiber content is increased, then the tensile strength and mechanical properties are improved, but the viscosity of the composite mixture increases making processing more difficult
Solution Approach 1:
A fiber length control agent is introduced as an intermediary substance to mediate between the fiber reinforcement and the polyurethane matrix. This agent prevents excessive fiber entanglement and aggregation, allowing high fiber content (up to 80 wt%) to be incorporated while maintaining processability. The control agent acts as a lubricant and spacing agent between fibers, reducing viscosity increases and enabling standard manufacturing processes to handle highly-filled composites.
Solution Approach 2:
The patent changes the physical and chemical parameters of the fiber-matrix interface by introducing the fiber length control agent. This modifies the interaction between fibers and matrix, altering the flow characteristics and viscosity behavior of the composite mixture. The control agent changes the effective fiber aspect ratio and distribution, enabling high fiber loading without the severe viscosity penalties that would normally occur.
2Strength
If the reinforcing inorganic fiber content is increased, then the mechanical reinforcement effect is enhanced, but fiber breakage and crushing increase during manufacturing
Solution Approach 1:
The fiber length control agent serves as a protective intermediary during the mixing and processing stages. It creates a buffer zone around fibers, reducing direct fiber-to-fiber contact and mechanical stress points that would cause breakage. This intermediary layer allows fibers to be transported and processed without excessive crushing, preserving their length and reinforcing capability even at high concentrations.
Solution Approach 2:
The control agent is incorporated beforehand into the composite mixture to provide preventive protection against fiber breakage. By establishing this protective mechanism prior to manufacturing operations, the system preemptively cushions fibers against the mechanical stresses of mixing, molding, and handling, ensuring fibers arrive at the final product with minimal degradation.
3Strength
If the fiber content is increased to improve mechanical properties, then the composite becomes more brittle and difficult to process, but reducing fiber content weakens the reinforcement
Solution Approach 1:
The fiber length control agent acts as a lubricating intermediary that enables high fiber content composites to be processed with ease comparable to lower fiber content materials. It reduces friction and inter-fiber friction, allowing the highly-filled composite to flow and be molded without requiring special handling or reduced fiber concentrations, thus decoupling fiber content from processing difficulty.
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 solution improves processing and maintains the reinforcing effect by reducing fiber breakage and enhancing mechanical properties, making it suitable for building materials like tiles and roofing products.
Implementation Method 1
a polyurethane formed by the reaction of (i) one or more isocyanates and (ii) one or more polyols
Data Source
AI summary
Composite panels and methods of preparation are described herein. In some embodiments, the composite panel can include a first fiber reinforcement, a polyurethane composite having a first surface and a second surface opposite the first surface, wherein the first surface is in contact with the first fiber reinforcement; and a cementitious material adjacent the first fiber reinforce-opposite the polyurethane composite. The polyurethane composite can be formed from (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, (ii) one or more polyols, and (iii) a particulate filler. The fiber reinforcement can be formed from a woven or non-woven material, such as glass fibers. The composite panel can further include a material, such as a second fiber reinforcement and a cementitious layer, in contact with the second surface of the polyurethane composite. Articles comprising the composite panels are also disclosed.