Polyurethane Window Interlayer Sound Attenuation
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Solution Overview
Problem
Conventional laminated windows with polyvinylbutyral (PVB) interlayers are costly due to the expensive extrusion process required for forming them, and there is a need for a non-extrusion method to produce laminated windows with improved sound attenuation properties.
Innovation Solution
A polyurethane interlayer is formed using a reaction mixture of chain extenders, polyether polyols, and aliphatic polyisocyanates, which can be cured to create a laminated window through a cast-in-place or reaction injection molding process, offering improved sound attenuation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polyvinylbutyral (PVB) interlayer is used in conventional laminated windows, then the interlayer can be formed into sheets, but the production cost increases due to the expensive extrusion process
Solution Approach 1:
The patent replaces the mechanical extrusion process with a chemical reaction approach. Instead of mechanically extruding PVB material through expensive equipment, the invention uses a chemical reaction between isocyanate and hydroxyl-containing compounds to form the interlayer material in-situ, eliminating the need for extrusion machinery and reducing production costs
Solution Approach 2:
The reaction mixture itself serves as the interlayer material that cures to form the final product. The chemical reaction components (isocyanate and hydroxyl compounds) react to form polyurethane or polyurea polymers directly within the window assembly, eliminating the need for separate manufacturing and installation steps
2Reliability
If conventional PVB interlayers are used, then the interlayer provides basic window functionality, but the sound attenuation properties are insufficient
Solution Approach 1:
The patent changes the material parameters by using polyurethane or polyurea polymers with specific molecular structures and densities that provide superior sound attenuation compared to conventional PVB. The reaction mixture can be formulated with specific ratios of isocyanate to hydroxyl compounds, and can include fillers or other additives to optimize acoustic properties while maintaining structural functionality
Solution Approach 2:
The invention creates a composite interlayer material by reacting isocyanate with hydroxyl-containing compounds to form polyurethane or polyurea polymers. This composite material combines the structural integrity needed for window functionality with acoustic damping properties that provide superior sound attenuation, effectively addressing both requirements simultaneously
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 polyurethane interlayer provides effective sound attenuation, particularly at high frequencies, and reduces production costs by eliminating the need for extrusion, while maintaining mechanical and optical properties suitable for automotive and architectural applications.
Implementation Method 1
reacting the following components to form a reaction mixture: (1) at least one chain extender; (2) at least one polyether polyol having a molecular weight of approximately 1,000; and (3) at least one aliphatic polyisocyanate; and curing the reaction mixture
Data Source
AI summary
The present invention discloses a method for forming a laminated window. The method includes: a) assembling a mold between two plies that make up a laminated window; b) filling the mold with a reaction mixture having: (1) at least one chain extender; (2) at least one polyether polyol having a molecular weight of approximately 1,000; and (3) at least one aliphatic polyisocyanate; and c) curing the reaction mixture.