Multilayer Glass Interlayer Structure for Acoustic Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer interlayers for glass panels, while providing good optical and mechanical properties, do not achieve optimal acoustic damping, particularly in reducing sound transmission, especially in vehicles and buildings with increased electronic device usage.
Innovation Solution
Development of multilayer interlayers comprising a soft core layer made of ethylene vinyl acetate copolymer and stiff skin layers, optimized for improved sound insulation properties, maintaining other desirable characteristics such as optical properties and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional multilayer interlayers are used, then good optical and mechanical properties are achieved, but acoustic damping performance is insufficient
Solution Approach 1:
The patent employs a composite interlayer structure consisting of a polyvinyl acetal resin layer and a polyurethane resin layer with specific molecular weight and hydroxyl value ranges. This composite material approach allows the polyvinyl acetal layer to provide optical clarity and mechanical strength while the polyurethane layer contributes superior acoustic damping properties, thereby resolving the contradiction between maintaining good optical/mechanical properties and improving acoustic performance.
Solution Approach 2:
The patent optimizes specific parameters of the polymer resins including molecular weight (5,000-500,000 for polyurethane), hydroxyl value (20-100 mg KOH/g for polyurethane), and resin ratio (30-70 wt% polyvinyl acetal, 70-30 wt% polyurethane). By precisely controlling these parameters, the interlayer achieves enhanced acoustic damping while preserving optical and mechanical properties, thus resolving the performance contradiction.
2Object-affected harmful factors
If single-layer interlayers are used, then manufacturing is simple, but acoustic insulation is insufficient
Solution Approach 1:
The patent divides the interlayer into two distinct functional segments: a polyvinyl acetal resin layer providing optical clarity and adhesion, and a polyurethane resin layer providing acoustic damping. This segmentation allows each layer to be optimized for its specific function while being manufactured as an integrated unit, thus improving acoustic insulation without excessive complexity increase.
Solution Approach 2:
The patent merges two different polymer resin systems (polyvinyl acetal and polyurethane) into a single composite interlayer structure that functions as one unified component between glass layers. This merging approach achieves superior acoustic insulation compared to single-layer designs while maintaining manufacturing simplicity through co-processing of the two resins.
3Object-affected harmful factors
If soft core layers are added for acoustic damping, then sound insulation improves, but mechanical strength may be compromised
Solution Approach 1:
The patent applies local quality by assigning different material properties to different layers: the polyvinyl acetal layer provides high mechanical strength and optical clarity where needed for structural integrity and appearance, while the polyurethane layer provides soft, damping properties specifically in the acoustic performance zone. This localized functional assignment resolves the contradiction between softness for acoustic damping and overall mechanical strength.
Solution Approach 2:
The composite structure combines a stiff polyvinyl acetal resin (providing mechanical strength) with a softer polyurethane resin (providing acoustic damping). The synergistic interaction between these two materials with complementary properties allows the interlayer to simultaneously achieve high mechanical strength and superior acoustic damping, resolving the contradiction between these opposing requirements.
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 interlayers exhibit enhanced sound transmission loss (STL) of at least 40 decibels at 4000 Hz and damping loss factor of at least 0.2, providing superior acoustic performance compared to conventional interlayers.
Implementation Method 1
a third polymer layer comprising an ethylene vinyl acetate copolymer having a vinyl acetate content of at least 70 weight percent, wherein the third polymer layer is between the first polymer layer and the second polymer layer
Implementation Method 2
The interlayers exhibit enhanced sound transmission loss (STL) of at least 40 decibels at 4000 Hz and damping loss factor of at least 0.2
Data Source
AI summary
Multilayered interlayers having improved acoustic properties comprising a stiff skin layer(s) and a soft core layer comprising EVA are disclosed. The multilayered interlayers comprise: a first polymer layer (skin layer); a second polymer layer (skin layer); and a third polymer layer (core layer) comprising ethylene vinyl acetate resin between the first polymer layer and the second polymer layer.