Polyurethane Optical Coatings 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-impact and harsh environment applications.
Innovation Solution
Development of polyurethanes and poly(ureaurethanes) through a reaction process involving specific branched polyols, polyisocyanates, and diols, maintained at elevated temperatures to produce materials with improved optical quality, impact resistance, and weatherability, without using polyester or 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 polycarbonates. This parameter change in the manufacturing process resolves the contradiction between impact resistance and optical quality.
2Strength
If polycarbonates are used to achieve high impact strength, then impact resistance is improved, but crack propagation resistance deteriorates
Solution Approach 1:
The patent employs composite material structures, particularly in the layered safety glass configuration where polycarbonate is combined with other materials. This composite approach maintains high impact strength while improving crack propagation resistance through the interaction between different material layers and the controlled morphology of the polymeric material.
3Object-affected harmful factors
If acrylics are used for optical applications, then scratch resistance is improved, but impact resistance deteriorates
Solution Approach 1:
The patent creates composite material systems where acrylic or polycarbonate base materials are combined with polymeric materials having specific glass transition temperatures. This composite structure allows the system to exhibit both the scratch resistance of acrylic and the high impact resistance of the polymeric material, resolving the contradiction between these two properties.
4Ease of manufacture
If polycarbonates are used to achieve flexibility, then ease of molding is improved, but weatherability deteriorates
Solution Approach 1:
The patent modifies the chemical structure and composition of the polymeric material by controlling the glass transition temperature and using specific monomer compositions. This parameter change enables the material to maintain flexibility and ease of molding while simultaneously improving weatherability and resistance to environmental degradation.
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 enhanced impact strength, ballistic resistance, solvent resistance, and weatherability, with the ability to be fabricated through casting or reaction injection molding, overcoming the limitations of existing polymeric materials.
Implementation Method 1
polyurethanes and poly(ureaurethanes) prepared from branched polyols, branched polyisocyanates and/or polyisocyanate trimers
Implementation Method 2
maintained at elevated temperatures to produce materials with improved optical quality, impact resistance, and weatherability
Data Source
AI summary
The present invention provides polyurethanes including a reaction product of components including: (a) at least one polyisocyanate selected from the group consisting of polyisocyanate trimers and branched polyisocyanates, the polyisocyanate having at least three isocyanate functional groups; and (b) at least one aliphatic polyol having 4 to 18 carbon atoms and at least two hydroxyl groups, wherein the reaction product components are essentially free of polyester polyol and polyether polyol; compositions, coatings and articles made therefrom and methods of making the same.