Cellulose Ester Multilayer Interlayers for Structural Laminates
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Solution Overview
Problem
Commercially available PVB interlayers in structural applications face deficiencies in processability and functionality, compromising their ability to provide structural support while maintaining optical clarity and stiffness, particularly in emerging architectural and load-bearing applications.
Innovation Solution
A multilayer interlayer comprising a non-cellulose ester layer, a tie layer of thermoplastic polymer resin, and a cellulose ester layer with a hydroxyl content of at least 0.5 weight percent and a glass transition temperature of at least 50°C, where the tie layer is disposed between the non-cellulose ester and cellulose ester layers, enhancing adhesion and structural support without compromising optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PVB interlayers are used in structural applications to provide structural support, then load-bearing capability is improved, but processability and functionality deficiencies occur
Solution Approach 1:
The patent uses a composite interlayer structure combining polyvinyl butyral (PVB) with cellulose ester layers and tie layers. This composite construction provides both structural support and improved processability, resolving the contradiction between strength requirements and manufacturing ease in structural applications.
2Strength
If PVB interlayers are used to achieve stiffness in structural applications, then load-bearing ability is improved, but optical clarity is compromised
Solution Approach 1:
The patent applies local quality by using thin tie layers and optimizing the distribution of cellulose ester layers to provide stiffness only where structurally necessary, while maintaining optical clarity in the overall interlayer structure. The selective placement of functional layers resolves the contradiction between achieving stiffness and preserving optical properties.
3Strength
If PVB interlayers are used in architectural applications to provide structural support, then load-bearing capability is improved, but functionality deficiencies occur
Solution Approach 1:
The patent creates a multi-functional interlayer system where the same composite structure provides both structural support (load-bearing capability) and enhanced functionality including improved processability, durability, and performance in architectural applications. The universal design addresses multiple requirements simultaneously.
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 configuration provides superior stiffness and maintains desirable optical properties, enabling its use in structural laminates with improved load-bearing capabilities and clarity, suitable for advanced architectural applications.
Implementation Method 1
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 has a glass transition ('Tg') temperature of at least 50° C.
Implementation Method 2
a tie layer comprising a thermoplastic polymer resin selected from polyurethane resin or ethylene vinyl acetate resin, wherein said tie layer is disposed between and in contact with the non-cellulose ester layer and said cellulose ester layer
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.