Polymeric Interlayer Resolving Rigidity Impact Trade-off

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Solution Overview

Problem

Conventional polymeric interlayers for safety glass panels often face a trade-off between rigidity, impact resistance, and optical clarity, where increasing rigidity compromises impact resistance, and enhancing impact strength sacrifices necessary structural support and aesthetic properties.

Innovation Solution

A monolithic interlayer comprising a single polymer layer with a poly(vinyl acetal) resin and a plasticizer, having a residual hydroxyl content of at least 19 weight percent and a glass transition temperature greater than 43°C, which maintains a balance of rigidity, impact resistance, and optical clarity when laminated between glass sheets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rigidity of conventional interlayers is increased, then structural support properties are improved, but the impact resistance of the resulting panel worsens

Engineering Contradiction:
ImproverigidityVSAvoidimpact resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the residual hydroxyl content (at least 19 weight percent) and glass transition temperature (greater than 43°C) of the poly(vinyl acetal) resin. These parameter specifications enable the interlayer to achieve both enhanced rigidity and maintained impact resistance, resolving the traditional trade-off between these properties.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional interlayers are formulated for enhanced impact strength, then impact resistance is improved, but the necessary rigidity required in applications requiring excellent structural support properties is lost

Engineering Contradiction:
Improveimpact resistanceVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent resolves this contradiction by establishing specific parameter ranges: residual hydroxyl content of at least 19 weight percent and glass transition temperature greater than 43°C. These controlled parameters enable the interlayer to simultaneously achieve enhanced impact strength and necessary rigidity, eliminating the need to sacrifice structural support properties.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If polymeric interlayers provide desirable optical properties, then aesthetic appeal is improved, but structural performance and impact resistance may be compromised

Engineering Contradiction:
Improveoptical clarityVSAvoidimpact resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent maintains optical clarity while ensuring impact resistance by controlling the resin composition parameters. The specified residual hydroxyl content (at least 19 weight percent) and glass transition temperature (greater than 43°C) enable the interlayer to achieve both optical desirability and impact performance without compromise.

Inventive Principle:
Principle #35Parameter changes

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 achieves enhanced rigidity and impact performance while maintaining low haze and no yellowing, making it suitable for various applications requiring structural and aesthetic properties.

Implementation Method 1

wherein said polymer layer has a plasticizer content of not more than 30 phr and a glass transition temperature greater than 43° C.

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

a single polymer layer comprising at least one poly(vinyl acetal) resin and at least one plasticizer, wherein said polymer layer has a plasticizer content of not more than 30 phr

Methodology Applied
Scientific EffectPlasticization:

Implementation Method 3

wherein said poly(vinyl acetal) resin has a residual hydroxyl content of at least 19 weight percent

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10926516B2Polymeric interlayers and multiple layer panels made therefrom exhibiting enhanced properties and performance
Publication Date: 2021.02.23 SOLUTIA INC

AI summary

Polymeric interlayers for use in making multiple layer panels having a unique balance of properties are provided. Single and multiple layer interlayers according to various embodiments of the present invention can be used to form multiple layer panels that exhibit both enhanced rigidity and improved impact resistance, while still retaining desirable optical performance. Interlayers and multiple layer panels of the present invention may be particularly suitable for use in a wide range of applications, including, for example, in many indoor and outdoor architectural and structural applications.