Polyurethane Laminates for Optical Quality and Impact Resistance
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Solution Overview
Problem
Current polymeric materials like polycarbonates and acrylics used in optical applications suffer from issues such as scratchability, optical distortions, inconsistent impact strength, poor crack propagation resistance, and limited weatherability, making them unsuitable for high-performance applications like aircraft canopies.
Innovation Solution
Development of polyurethanes and poly(ureaurethanes) through a reaction process involving specific polyisocyanates, branched polyols, and diols, maintained at elevated temperatures to create materials with enhanced optical quality, impact resistance, and improved weatherability, avoiding the use of polyester and polyether polyols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonates are used for optical applications, then impact resistance is improved, but optical quality deteriorates due to extrusion distortions and birefringence
Solution Approach 1:
The patent changes the processing method from extrusion to casting or reaction injection molding, which eliminates the directional extrusion distortions and birefringence while maintaining the high impact resistance of polycarbonate-like materials. This parameter change in the manufacturing process resolves the contradiction between impact resistance and optical quality.
Solution Approach 2:
The patent develops multilayer laminated articles combining polyurethane layers with other materials, creating composite structures that achieve both high impact resistance and excellent optical quality. The composite approach allows each layer to contribute specific properties, resolving the trade-off between strength and optical precision.
2Object-affected harmful factors
If acrylics are used for optical applications, then scratch resistance is improved, but impact resistance and heat distortion temperature deteriorate
Solution Approach 1:
The patent creates multilayer laminated structures where polyurethane layers provide impact resistance and heat distortion resistance, while surface coatings or laminate layers provide scratch resistance. This composite approach allows the material to achieve both scratch resistance and high impact resistance simultaneously.
3Strength
If polycarbonates are used for high impact strength applications, then impact strength is improved, but crack propagation resistance and weatherability deteriorate
Solution Approach 1:
The patent develops multilayer laminated articles where the polyurethane layers are combined with interlayer materials that provide crack propagation resistance. The laminate structure allows cracks to be arrested at layer interfaces, improving reliability while maintaining high impact strength.
Solution Approach 2:
The patent modifies the chemical composition and molecular structure of the polyurethane layers through specific synthesis methods, improving crack propagation resistance and weatherability while maintaining impact strength. Changes in crosslinking density and polymer composition resolve this contradiction.
4Productivity
If polycarbonates are extruded for manufacturing, then productivity is improved, but optical quality deteriorates due to extrusion distortions
Solution Approach 1:
The patent changes the processing method from extrusion to casting or reaction injection molding. While these methods may be slightly slower than extrusion, they eliminate the need for additional post-processing steps to remove optical distortions, actually improving overall productivity while achieving superior optical quality.
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 resulting materials exhibit high impact strength, good ballistics resistance, and excellent weatherability, with the ability to be fabricated through casting or reaction injection molding, offering superior performance compared to traditional polymers.
Implementation Method 1
polyurethanes and poly(ureaurethanes) prepared from branched polyols, branched polyisocyanates and/or polyisocyanate trimers
Implementation Method 2
maintained at a temperature of at least about 100° C. for at least about 10 minutes
Data Source
AI summary
The present invention provides laminates including: (a) at least one layer of at least one polyurethane including a reaction product of components including: (i) at least one polyisocyanate; (ii) at least one branched polyol having 4 to 18 carbon atoms and at least 3 hydroxyl groups; and (iii) at least one diol having 2 to 18 carbon atoms wherein the reaction components are maintained at a temperature of at least about 100° C. for at least about 10 minutes; and (b) at least one layer of a substrate selected from the group consisting of paper, glass, ceramic, wood, masonry, textile, metal or organic polymeric material and combinations thereof; and methods of making the same.