Modified Fumed Silica in PVB Interlayers

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Solution Overview

Problem

Interlayers used in multiple layer glazing applications often have a low tensile modulus due to composition changes for noise attenuation, making them unsuitable for certain applications, and they require improved handling and sound suppression qualities.

Innovation Solution

Incorporating modified fumed silica with a hydrophobic character into polymer interlayers, specifically poly(vinyl butyral) sheets, to enhance tensile modulus, moisture resistance, and glass adhesion, while maintaining low glass transition temperatures and optical clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If composition changes are employed to attain a low glass transition temperature for noise attenuation, then the sound attenuation performance is improved, but the tensile modulus becomes less than desirable

Engineering Contradiction:
Improvesound attenuation performanceVSAvoidtensile modulus
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite material system consisting of poly(vinyl butyral) polymer combined with modified fumed silica particles. The fumed silica serves as a reinforcing filler that increases the tensile modulus of the interlayer composition, thereby resolving the contradiction between achieving low glass transition temperature for noise attenuation and maintaining adequate tensile modulus for structural integrity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If composition changes are employed to attain a low glass transition temperature for noise attenuation, then the sound attenuation performance is improved, but the handling properties become unsuitable

Engineering Contradiction:
Improvesound attenuation performanceVSAvoidhandling properties
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The composite material system of poly(vinyl butyral) with modified fumed silica not only improves tensile modulus but also enhances handling properties. The fumed silica reinforcement provides structural support that enables the interlayer to be handled and installed effectively while maintaining the low glass transition temperature required for noise attenuation performance.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional fumed silica is used, then the interlayer can be formulated, but moisture resistance and adhesion to glass are insufficient

Engineering Contradiction:
ImproveformulabilityVSAvoidmoisture resistance and adhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the surface properties of fumed silica by altering its chemical parameters, specifically introducing hydrophobic character through modification. This parameter change enhances the moisture resistance and adhesion to glass of the interlayer composition, resolving the contradiction between ease of formulation and reliability of performance properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The modification of fumed silica creates local quality differences in the interlayer composition, with the modified silica particles providing localized hydrophobic regions that improve moisture resistance and enhance adhesion to glass surfaces, while the bulk polymer matrix maintains its formulation properties.

Inventive Principle:
Principle #3Local quality

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 modified fumed silica interlayers demonstrate improved tensile modulus, creep performance, and adhesion to glass, suitable for various applications including acoustic uses, with enhanced handling and noise suppression without compromising optical quality.

Implementation Method 1

fumed silica that has been modified to impart hydrophobic character

Methodology Applied
Scientific EffectHydrophobic character: Hydrophobe

Data Source

PatentEP2040918B8Interlayers comprising modified fumed silica
Publication Date: 2013.10.02 SOLUTIA INC

AI summary

The present invention includes polymer interlayers that are used in multiple layer glazing panels. Interlayers of the present invention comprise a thermoplastic polymer, a plasticizer, and a fumed silica that has been modified to impart hydrophobic character. Interlayers incorporating such components have improved tensile modulus, moisture resistance, creep performance, anticorrosion effect, glass adhesion, and are well suited to a variety of applications, including, but not limited to, acoustic applications.