Thermoplastic Polyurethane Interlayer Adhesion Transparency Trade-off
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Solution Overview
Problem
Existing thermoplastic polyurethane interlayers face issues with transparency, haze, and hydrolytic stability, particularly when used in humid or cold conditions, and are not compatible with polycarbonate substrates, while polyvinyl butyrate interlayers have limitations in high and low temperatures and bird impact resistance.
Innovation Solution
A composition comprising a polyether polyol and a low molecular weight polyester polyol, combined with an isocyanate, which forms a thermoplastic polyurethane interlayer with improved adhesion, humidity resistance, and temperature stability, allowing for compatibility with various substrates including polycarbonate, and maintaining clarity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hard segment content of TPU interlayer is increased to improve strength and adhesion, then the interlayer becomes hazy and transparency deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating polyester polyol into the TPU system, which modifies the hard segment structure to maintain adhesion while reducing haze formation, thus resolving the contradiction between strength and transparency
Solution Approach 2:
The patent creates a composite TPU system combining polyether polyol and polyester polyol components, where the polyester portion modifies the hard segment characteristics to achieve both high adhesion and maintained transparency without the usual haze problem
2Ease of manufacture
If polyester-based polyurethanes are used to improve adhesion and processability, then hydrolytic stability deteriorates under humid conditions
Solution Approach 1:
The patent merges polyether polyol and polyester polyol components into a single TPU system, combining the hydrolytic stability of polyether with the processability and adhesion benefits of polyester, thus resolving the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent creates a composite polyol system where polyester polyol provides processability and adhesion while polyether polyol contributes hydrolytic stability, achieving both ease of manufacture and reliability simultaneously
3Ease of manufacture
If polyvinyl butyrate interlayers are used to improve cost and processing advantages, then performance at extreme temperatures and bird impact resistance deteriorates
Solution Approach 1:
The patent changes the material composition from vinyl to TPU-based system with specific polyol ratios and hard segment content optimization, achieving both processing advantages and improved bird impact resistance through controlled physical and chemical properties
4Reliability
If polyether-based polyurethanes are used to improve hydrolytic stability, then performance at lower temperatures deteriorates
Solution Approach 1:
The patent creates a composite polyol system where polyester polyol improves low-temperature flexibility and polyether polyol provides hydrolytic stability, resolving the contradiction between reliability and temperature performance
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 interlayer maintains adhesion and optical clarity across a broad temperature range, enhances resistance to impact and humidity, and is compatible with diverse substrates, improving performance in extreme conditions compared to conventional systems.
Implementation Method 1
The soft segments include lower polarity segments that are rather long and the hard segments include higher polarity segments that are rather short. Both segments are linked together covalently to form block co-polymers.
Implementation Method 2
The interlayer can be laminated onto a substrate, or between two or more substrates, to form, for example, a transparency
Data Source
AI summary
A composition includes an isocyanate, a polyether diol, a branched short chain diol having a backbone including carbon atoms in a range of 1 to 9 and at least one branching group, and a cross-linker having a hydroxyl functionality in a range of 2.2 to 4. A films includes the composition and an interlayer includes the film. Transparencies including the interlayer and methods of making the same are further disclosed.