Stiff PVB Recovery via Plasticizer Selective Solvation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The recycling of poly(vinyl butyral) (PVB) scrap material from multi-layer glass panels is challenging due to the differences in composition between the stiff skin layers and soft core layers, leading to visual defects and inferior product quality when re-extruded, as the materials do not mix well in the melt phase.
Innovation Solution
A process involving grinding the PVB multilayer sheet to create granulates, adding additional plasticizer to selectively remove the soft PVB, and using techniques like decanting, filtering, or centrifuging to separate the stiff and soft PVB components, allowing for the enrichment of stiff PVB granulates and the production of high-quality interlayers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If multi-layer PVB sheets with different composition layers are recycled by grinding and re-extrusion, then scrap material can be reused, but visual defects appear due to poor mixing of stiff and soft PVB components in the melt phase
Solution Approach 1:
The patent applies segmentation by separating the multi-layer PVB sheet into distinct granulate fractions based on their stiffness characteristics. Through controlled grinding and size-based separation, the stiff skin layers and soft core layers are divided into different granulate size ranges, preventing their inadequate mixing during re-extrusion and eliminating visual defects while enabling scrap reuse.
Solution Approach 2:
The patent applies local quality by assigning different granulate size specifications to different applications. Coarser granulates are used where structural properties are prioritized, while finer granulates are used where visual clarity is critical. This localized quality assignment ensures that each recycled granulate fraction is used in applications where its specific properties are advantageous, maintaining overall product quality.
2Manufacturing precision
If additional plasticizer is added to remove soft PVB selectively, then stiff PVB can be enriched, but the process complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying plasticizer content across different granulate fractions. By controlling the amount of plasticizer added during the enrichment process, the patent selectively removes soft PVB components while retaining stiff PVB, achieving precise composition control. This parameter-based differentiation allows composition tailoring for specific applications without requiring complex additional equipment.
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
This method effectively recovers stiff PVB from plasticized PVB multilayer sheets, enabling the production of high-quality PVB interlayers with improved visual clarity and reduced environmental impact by maximizing scrap reuse and reducing the need for virgin resin production.
Implementation Method 1
adding additional plasticizer to remove at least a portion of the soft poly(vinyl butyral) from the poly(vinyl butyral) granulate
Implementation Method 2
separating the granulate enriched in the stiff poly(vinyl butyral) from the soft poly(vinyl butyral) and additional plasticizer
Data Source
AI summary
Processes are disclosed for recovering stiff poly(vinyl butyral) from a plasticized poly(vinyl butyral) multilayer sheet containing the stiff poly(vinyl butyral) and soft poly(vinyl butyral). The processes include grinding the plasticized poly(vinyl butyral) multilayer sheet to obtain a granulate; adding additional plasticizer to the granulate to remove at least a portion of the soft poly(vinyl butyral); and physically separating the granulate from the resulting solution.