PVB Recovery Process for Uniform Residual PVOH and Low Haze
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Solution Overview
Problem
The recycling of poly(vinyl butyral) (PVB) materials from post-industrial and post-consumer sources is challenging due to compositional differences leading to high haze and discoloration, making it difficult to produce PVB with a specific composition suitable for laminated glass panels.
Innovation Solution
A process involving a reclamation system with solvent dissolution, catalyst addition, and controlled equilibration of PVB reaction mixtures to achieve uniform residual polyvinyl alcohol (PVOH) content, followed by filtration and solvent extraction to produce high-quality PVB for interlayers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If post-industrial and post-consumer PVB materials are recycled, then production costs are reduced and environmental footprint is decreased, but compositional differences cause high haze and discoloration
Solution Approach 1:
The patent segments the PVB recycling process into distinct stages: dissolution of PVB materials in solvent, filtration to remove contaminants, and controlled precipitation to recover PVB. This segmentation allows each stage to address specific issues - dissolution handles compositional differences, filtration removes contaminants, and precipitation controls composition uniformity, thereby resolving the contradiction between material recovery and composition precision.
Solution Approach 2:
The patent employs parameter changes by controlling the solvent composition, temperature, and precipitation conditions to achieve uniform PVB composition from heterogeneous recycled materials. By adjusting these parameters, the process transforms mixed PVB compositions into a uniform product with controlled haze and discoloration, resolving the contradiction between recovering diverse PVB materials and producing uniform composition.
2Quantity of substance
If PVB materials of different compositions are mixed together, then the quantity of recyclable material increases, but chemical incompatibility results in hazy or cloudy material
Solution Approach 1:
The patent uses a solvent as an intermediary medium to dissolve PVB materials of different compositions. The solvent acts as a mediator that allows heterogeneous PVB materials to be combined and then reprecipitated into a uniform composition, enabling large quantities of recycled material to be processed while minimizing haze and discoloration through controlled phase separation.
Solution Approach 2:
The patent utilizes phase transitions by dissolving PVB materials in a solvent and then controlling the precipitation process. This phase transition approach allows mixed compositions to be transformed into a uniform solid phase with controlled optical properties, enabling high-volume recycling while reducing haze and discoloration through controlled crystallization.
3Reliability
If the synthesis process uses non-renewable feedstocks and energy-intensive processes, then PVB resin can be produced, but environmental footprint and production costs increase
Solution Approach 1:
The patent applies discarding and recovering by collecting post-industrial and post-consumer PVB materials that would otherwise be discarded, and recovering them through dissolution and precipitation. This closed-loop approach replaces energy-intensive virgin PVB synthesis with a lower-impact recycling process, maintaining reliable PVB production while significantly reducing environmental footprint.
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 process effectively recycles PVB into a uniform composition suitable for laminated glass panels, reducing environmental impact and production costs by utilizing post-industrial and post-consumer materials.
Implementation Method 1
mixing a PVB feed composition with a solvent, a catalyst, and optionally butyraldehyde to produce an equilibrated PVB-containing composition
Implementation Method 2
mixing a PVB feed composition with a solvent, a catalyst, and optionally butyraldehyde to produce an equilibrated PVB-containing composition
Implementation Method 3
The mixture may be heated to a temperature of between 65°C and 85°C, between 70°C and 80°C, between 70°C and 78°C, or about 78°C
Implementation Method 4
The equilibrated PVB reaction mixture may then be transferred to a filtering tank 16 where the equilibrated PVB reaction mixture may be filtered to remove salts and other remaining solids
Implementation Method 5
remaining solvent may be extracted, such as through evaporation
Implementation Method 6
remaining solvent may be extracted, such as through evaporation
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A method of recovering poly(vinyl butyral) (PVB). The process comprises mixing a PVB feed composition with a solvent, a catalyst, and, optionally, butyraldehyde to produce an equilibrated PVB-containing composition. The PVB feed composition comprises at least two different PVB- containing compositions. An additional step includes determining a residual polyvinyl alcohol (PVOH) content of the equilibrated PVB-containing composition. A further step includes adjusting the amount of butyraldehyde used in the mixing step based on the determined residual PVOH content.