Polymeric Interlayer Segmentation for Rigidity and Impact Balance

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Solution Overview

Problem

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

Innovation Solution

The development of polymeric interlayers comprising multiple layers of thermoplastic poly(vinyl acetal) resins with varying residual hydroxyl and acetate contents, along with specific plasticizer distributions, to achieve a balance of rigidity, impact resistance, and optical clarity, including low haze and no yellowing, suitable for a wide range of applications.

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 resin compositions and plasticizer contents. The outer layers have higher plasticizer content (30-40 phr) for flexibility and impact resistance, while the inner layer has lower plasticizer content (15-25 phr) for rigidity and structural support, resolving the contradiction between rigidity and impact resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the interlayer are assigned different properties: the outer layers are formulated to be more flexible and impact-resistant, while the inner layer is formulated to be stiffer and provide structural support. This local differentiation allows the interlayer to simultaneously achieve both rigidity and impact resistance

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional interlayers are formulated for enhanced impact strength, then impact resistance is improved, but the necessary rigidity required for structural support is compromised

Engineering Contradiction:
Improveimpact resistanceVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The interlayer is segmented into multiple layers with differentiated resin compositions and plasticizer contents. The outer layers contain higher plasticizer (30-40 phr) for impact resistance, while the inner layer contains lower plasticizer (15-25 phr) for rigidity, allowing both properties to coexist in different regions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlayer exhibits local quality differentiation where outer layers are optimized for impact absorption while the inner layer is optimized for structural rigidity, enabling the panel to achieve both enhanced impact strength and necessary rigidity simultaneously

Inventive Principle:
Principle #3Local quality

3Strength

If multiple layer panels are used for structural applications, then structural support properties are improved, but aesthetic characteristics may be compromised

Engineering Contradiction:
Improvestructural supportVSAvoidaesthetic characteristics
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The resin composition parameters are carefully controlled to maintain optical clarity. The interlayer uses poly(vinyl acetal) resins with specific residual hydroxyl and acetate contents, and precise plasticizer formulations, to ensure low haze and no yellowing while providing structural support properties

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3471958B1Polymeric interlayers and multiple layer panels made therefrom exhibiting enhanced properties and performance
Publication Date: 2023.10.18 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.