Cellulose Ester Multilayer Interlayers for Structural Laminates
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Solution Overview
Problem
Current interlayers used in structural laminates, such as those in architectural glass applications, face challenges in providing sufficient structural support while maintaining optical clarity and processability, with many commercially available PVB interlayers exhibiting deficiencies in these areas.
Innovation Solution
A multilayer interlayer comprising a non-cellulose ester layer, a cellulose ester layer with a high hydroxyl content and glass transition temperature, and adhesive coatings containing silanol agents, which are strategically positioned to enhance adhesion and structural integrity without compromising optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PVB interlayers are used to provide structural support in laminated glass, then load bearing ability is improved, but optical clarity and processability deteriorate
Solution Approach 1:
The patent uses a composite interlayer structure combining poly(vinyl acetal) resin with cellulose ester layers. The cellulose ester provides structural stiffness and load-bearing capacity, while the poly(vinyl acetal) matrix maintains optical clarity and processability. This composite approach allows the interlayer to achieve both structural performance and manufacturing suitability.
Solution Approach 2:
The patent modifies the glass transition temperature parameter of the cellulose ester to at least 50°C to enhance structural stability and load-bearing capacity. This parameter change allows the interlayer to maintain its shape and provide structural support while remaining processable during manufacturing operations.
2Strength
If PVB interlayers are used to provide structural support in laminated glass, then load bearing ability is improved, but optical clarity deteriorates
Solution Approach 1:
The composite structure combines cellulose ester (providing structural support) with poly(vinyl acetal) resin (providing optical clarity). The cellulose ester content is controlled to provide necessary structural strength while minimizing impact on optical properties, achieving both load-bearing ability and clarity.
3Strength
If cellulose ester with high hydroxyl content is used, then adhesion is improved, but processability deteriorates
Solution Approach 1:
The patent specifies a hydroxyl content parameter for the cellulose ester to maintain adhesion while ensuring processability. The controlled hydroxyl content allows sufficient bonding to glass substrates and other interlayer materials without causing excessive moisture absorption or processing difficulties.
Solution Approach 2:
The poly(vinyl acetal) resin acts as an intermediary matrix that accommodates the cellulose ester layers. This intermediary material provides a processable base that can be manufactured while the cellulose ester layers provide the necessary adhesion through their hydroxyl groups.
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 proposed interlayer design provides superior stiffness and maintains desirable optical properties, enabling it to support structural loads effectively while ensuring clarity and stability in glass panels.
Implementation Method 1
an adhesive coating comprising at least one silanol-containing agent, wherein said adhesive coating is at least partially interposed between said non-cellulose ester layer and said cellulose ester layer
Implementation Method 2
a cellulose ester layer comprising at least one cellulose ester having a hydroxyl content of at least 0.5 weight percent based on the entire weight of the cellulose ester, wherein said cellulose ester layer has a glass transition ('Tg') temperature of at least 50° C.
Data Source
AI summary
An interlayer structure having a cellulose ester layer for use in structural laminates is described herein. The cellulose ester layer provides rigidity and support to multilayer interlayers comprising an array of different layers. Due to the diverse properties of the cellulose ester layers, the present interlayers can be useful in producing structural laminates having high stiffness and which possess good optical clarity for a variety of applications, including outdoor structural applications.