Polymeric Interlayer with Differential Hydroxyl Content for Rigidity and Impact

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Solution Overview

Problem

Conventional polymeric interlayers for safety glass panels often compromise between rigidity and impact resistance, failing to provide an optimal balance of structural, aesthetic, and optical properties, with increased rigidity typically leading to reduced impact resistance and vice versa.

Innovation Solution

A polymeric interlayer comprising a first outer polymer layer with a poly(vinyl acetal) resin and a second outer polymer layer, both containing plasticizers, where the difference in residual hydroxyl content between the two layers is at least 5 weight percent, achieving enhanced rigidity and impact performance while maintaining low haze and optical clarity.

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 interlayer is divided into multiple layers with different residual hydroxyl content. The outer layers have one residual hydroxyl content range while inner layers have a different residual hydroxyl content range, allowing each layer to contribute different properties (rigidity from outer layers, impact resistance from inner layers) to resolve the contradiction between rigidity and impact resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the interlayer are assigned different residual hydroxyl content to provide locally optimized properties. Outer layers are formulated with specific residual hydroxyl content for rigidity, while inner layers use different residual hydroxyl content for impact resistance, achieving both requirements simultaneously

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional interlayers are formulated for enhanced impact strength, then impact resistance is improved, but necessary rigidity is lost

Engineering Contradiction:
Improveimpact resistanceVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The interlayer is divided into multiple layers with different residual hydroxyl content. The outer layers have one residual hydroxyl content range while inner layers have a different residual hydroxyl content range, allowing each layer to contribute different properties (rigidity from outer layers, impact resistance from inner layers) to resolve the contradiction between rigidity and impact resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the interlayer are assigned different residual hydroxyl content to provide locally optimized properties. Outer layers are formulated with specific residual hydroxyl content for rigidity, while inner layers use different residual hydroxyl content for impact resistance, achieving both requirements simultaneously

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a single polymeric composition is used in the interlayer, then manufacturing simplicity is maintained, but the balance of structural, performance, and aesthetic properties cannot be optimized

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidbalance of properties
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The interlayer is divided into multiple layers with different residual hydroxyl content. The outer layers have one residual hydroxyl content range while inner layers have a different residual hydroxyl content range, allowing each layer to contribute different properties (rigidity from outer layers, impact resistance from inner layers) to resolve the contradiction between rigidity and impact resistance

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS10589495B2Polymeric interlayers and multiple layer panels made therefrom exhibiting enhanced properties and performance
Publication Date: 2020.03.17 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.