Recycled PVB Recovery by Selective Dissolution and Filtration
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Solution Overview
Problem
The recycling of post-industrial and post-consumer poly(vinyl butyral) (PVB) is hindered by compositional differences between core and skin layers, leading to haze and discoloration due to immiscible microdomains, limiting its reuse in laminated glass applications.
Innovation Solution
A method involving solvent extraction and filtration to separate high poly(vinyl alcohol) (PVOH) PVB resin and plasticizer from low PVOH PVB solids, followed by further processing to obtain clear PVB polymer suitable for new laminated glass panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If post-industrial and post-consumer PVB is recycled directly, then material reuse is achieved, but compositional differences between core and skin layers cause haze and discoloration
Solution Approach 1:
The patent separates the multilayer PVB interlayer into individual layers, isolating the core layer from the skin layers. This segmentation allows selective processing of each layer type, preventing the compositional incompatibility that causes haze when different PVB compositions are mixed together.
Solution Approach 2:
The patent extracts and removes the core layer material from the multilayer structure through selective dissolution and filtration. By taking out the core layer PVB (which has different composition from skin layers) separately, the process avoids mixing incompatible PVB compositions that would create immiscible microdomains and haze.
2Productivity
If multilayer interlayers are recycled through conventional methods, then some material recovery is achieved, but the different compositions of core and skin layers create immiscible microdomains
Solution Approach 1:
The patent divides the multilayer interlayer into separable components (core layer and skin layers) through selective dissolution. This segmentation enables independent processing of each layer type, maintaining compositional homogeneity in the recovered PVB and preventing the formation of immiscible microdomains that would occur with conventional mixing methods.
Solution Approach 2:
The patent changes the chemical parameters of the dissolution system by selecting specific solvents that selectively dissolve either the core layer or skin layer PVB. This parameter change allows for selective extraction and separation based on compositional differences, achieving both high recycling efficiency and compositional stability in the recovered material.
3Quantity of substance
If PVB from different manufacturers and products is mixed, then recycling volume increases, but compositional differences lead to unacceptable haze
Solution Approach 1:
The patent segments PVB material by its compositional characteristics (core layer vs. skin layer types) rather than by source. This allows aggregation of large volumes of recycled PVB from different manufacturers and products while maintaining optical quality, as long as the materials are separated into compositionally homogeneous groups through the selective dissolution process.
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 method achieves clear PVB polymer with minimal haze, enabling its reuse in laminated glass panels and other products, reducing environmental impact and economic loss.
Implementation Method 1
adding recycled PVB to the solvent and stirring to form a PVB mixture, wherein the PVB mixture comprises a liquid portion comprising dissolved high PVOH PVB resin and plasticizer, and a solid portion comprising low PVOH PVB solids
Implementation Method 2
filtering the PVB mixture to remove the low PVOH PVB solids
Data Source
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AI summary
A method of recovering poly(vinyl butyral) (PVB). The method comprises a step of providing a solvent to a reclamation system; adding recycled PVB to the solvent and stirring to form a PVB mixture, wherein the PVB mixture comprises a liquid portion comprising dissolved high PVOH PVB resin and plasticizer, and low PVOH PVB solids and plasticizer; and filtering the PVB mixture to remove the low PVOH PVB solids.