Polymeric Interlayer Segmentation for Rigidity and Impact Balance

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Solution Overview

Problem

Conventional polymeric interlayers in 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 leading to worsened impact resistance and vice versa.

Innovation Solution

A polymeric interlayer comprising a first polymer layer with a poly(vinyl acetal) resin and a second polymer layer with a different resin, where the poly(vinyl acetal) resin has a residual hydroxyl content of at least 19 weight percent and the plasticizer content is not more than 30 parts per hundred resin, and the glass transition temperatures of the layers are appropriately differentiated to enhance rigidity and impact performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

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

Engineering Contradiction:
ImproverigidityVSAvoidimpact resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The interlayer is divided into multiple distinct polymer layers, each with different glass transition temperatures and mechanical properties. This segmentation allows each layer to contribute differently to the overall performance - some layers providing rigidity while others provide impact resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the glass transition temperature parameter across different layers, with at least one layer having Tg greater than 43°C and another layer having Tg at least 5°C lower. This parameter differentiation enables the interlayer to exhibit both rigid behavior at service temperature and ductile behavior during impact, simultaneously achieving structural support and impact resistance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

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

Engineering Contradiction:
Improveimpact resistanceVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The interlayer is divided into multiple distinct polymer layers, each with different glass transition temperatures and mechanical properties. This segmentation allows each layer to contribute differently to the overall performance - some layers providing rigidity while others provide impact resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the glass transition temperature parameter across different layers, with at least one layer having Tg greater than 43°C and another layer having Tg at least 5°C lower. This parameter differentiation enables the interlayer to exhibit both rigid behavior at service temperature and ductile behavior during impact, simultaneously achieving structural support and impact resistance.

Inventive Principle:
Principle #35Parameter changes

3Strength

If polymeric interlayers provide excellent structural support properties, then rigidity is improved, but optical clarity deteriorates

Engineering Contradiction:
ImproverigidityVSAvoidoptical clarity
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

Different polymer layers are assigned different local qualities - some layers are optimized for rigidity with higher glass transition temperatures, while other layers are optimized for optical clarity with lower glass transition temperatures and appropriate plasticizer content. This local differentiation allows the overall interlayer to achieve both structural support and optical transparency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS10668691B2Polymeric interlayers and multiple layer panels made therefrom exhibiting enhanced properties and performance
Publication Date: 2020.06.02 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.