Multilayered Acoustic Polymer Interlayers for Iceflower Resistance
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Solution Overview
Problem
Conventional multilayered glass panels often develop optical defects known as iceflowers or snowflakes due to residual air trapped between the glass and interlayer, which leads to stress and reduced structural integrity, especially in warm climates where temperatures elevate, causing air bubbles to form and expand, compromising the panel's appearance and integrity.
Innovation Solution
The development of multilayered interlayers with high flow skin layers, comprising plasticized poly(vinyl butyral) with molecular weights less than 140,000 Daltons, and a central core layer, along with embossed surfaces to enhance air escape during de-airing, reducing stress and optical defects without compromising sound insulation, mechanical strength, or impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multilayered interlayers are used, then sound insulation and mechanical strength are maintained, but trapped air forms iceflowers and optical defects under thermal stress
Solution Approach 1:
The interlayer is designed with different molecular weight PVB layers in specific positions: lower molecular weight (100,000-140,000 Daltons) in skin layers for flow and air escape, higher molecular weight (140,000-200,000 Daltons) in core layers for mechanical strength. This spatial differentiation of material properties resolves the contradiction by allowing air to escape at interfaces while maintaining overall structural integrity.
Solution Approach 2:
The patent changes the molecular weight parameter of PVB to resolve the contradiction. Lower molecular weight PVB (100,000-140,000 Daltons) provides higher flow characteristics that enable air to escape during curing, preventing iceflower formation. This parameter change maintains sound insulation and mechanical strength while eliminating optical defects.
2Reliability
If lower molecular weight PVB is used to improve air escape, then iceflower formation is reduced, but mechanical strength may be compromised
Solution Approach 1:
The patent applies local quality by positioning lower molecular weight PVB (100,000-140,000 Daltons) specifically in skin layers where air escape is needed, while placing higher molecular weight PVB (140,000-200,000 Daltons) in core layers where mechanical strength is critical. This spatial differentiation allows each layer to optimize its function without compromising the other.
Solution Approach 2:
The patent creates a composite interlayer structure combining different molecular weight PVB layers. The composite consists of low molecular weight layers (for air escape and flow) and high molecular weight layers (for mechanical strength and adhesion), achieving both iceflower resistance and structural integrity through material composition.
3Use of energy by moving object
If multilayered interlayers are used for acoustic performance, then sound insulation is improved, but trapped air bubbles form and expand in warm climates
Solution Approach 1:
The patent applies local quality by designing specific skin layers with lower molecular weight PVB (100,000-140,000 Daltons) that have enhanced flow characteristics. These localized zones allow air bubbles to escape during the curing process, preventing the formation and expansion of air pockets that would otherwise occur in warm climates, while the multilayered structure maintains acoustic performance.
4Reliability
If embossed surfaces are added to enhance air escape, then de-airing is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by adding embossed surfaces only to the skin layers that are in direct contact with glass, where air escape is most critical. The core layers remain smooth for manufacturing simplicity. This localized embossing provides effective de-airing pathways without unnecessarily complicating the entire interlayer structure.
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 solution effectively reduces or eliminates trapped air and stress, significantly minimizing the formation of iceflowers while maintaining the acoustic and optical properties of conventional multilayered interlayers, enhancing the structural integrity and aesthetic appeal of glass panels.
Implementation Method 1
The skin layers have different rheology properties than the core layer(s), specifically higher flow characteristics that allow the interlayer to better accommodate stress and reduce the formation of air bubbles
Implementation Method 2
The skin layers may have an embossed surface roughness that differs from the core layer(s). The increased surface roughness can enhance air escape during the de-airing process
Implementation Method 3
The skin layers may have a different glass transition temperature than the core layer(s). This can be achieved by modifying the polymer resin type, molecular weight, or plasticizer content
Data Source
AI summary
This disclosure is related to the field of polymer interlayers for multiple layer glass panels and multiple layer glass panels having at least one polymer interlayer sheet. Specifically, this disclosure is related to the field of polymer interlayers comprising multiple thermoplastic layers which resist the formation of optical defects.