Multilayer Sorbent Membrane Coextrusion
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Solution Overview
Problem
Existing methods for manufacturing multilayer sorbent polymeric membranes are complex, leading to low productivity and performance due to residual solvents, poor adhesion between layers, and limited sorbability and porosity retention.
Innovation Solution
A continuous single-step method for producing multilayer sorbent polymeric membranes through coextrusion of layer-forming compositions containing sorbent materials and a diluent, followed by cooling and diluent extraction, which results in a membrane with high sorbability, porosity, and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If discrete multistep processes (laminating and coating) are used to manufacture multilayer absorbent membranes, then layer adhesion can be improved through surface treatment and adhesives, but productivity decreases and the interface is altered or contaminated
Solution Approach 1:
The patent combines multiple discrete manufacturing steps (lamination, coating, surface treatment) into a single continuous extrusion process. The multilayer membrane is formed by coextruding molten polymer compositions through a multi-layer die, eliminating the need for separate lamination and coating operations. This integration maintains layer adhesion through molecular entanglement during extrusion while dramatically improving productivity by removing intermediate handling and processing steps.
Solution Approach 2:
The patent performs preliminary mixing of the polymer matrix and absorbent particles within the extrusion system itself. The polymer composition is prepared with embedded absorbent materials before extrusion, ensuring uniform distribution and proper adhesion from the outset. This preliminary preparation eliminates the need for subsequent surface treatments or adhesive applications that would reduce productivity.
2Quantity of substance
If monolithic symmetric membranes with extremely high content of inorganic particles are used, then sorbability can be increased, but mechanical strength decreases
Solution Approach 1:
The patent creates multilayer membranes with different compositions in different layers. One layer contains high absorbent content for sorbability, while another layer contains polymer-rich composition for mechanical strength. This local differentiation allows each layer to optimize its function without compromising the overall membrane structure. The layers are bonded together through coextrusion, maintaining both high sorbent content and adequate mechanical properties.
3Manufacturing precision
If multiple discrete manufacturing steps are used, then manufacturing precision can be controlled, but the process complexity increases and residual solvents remain
Solution Approach 1:
The patent merges multiple discrete manufacturing operations into a single continuous extrusion process. The multilayer membrane is formed in one continuous operation by coextruding different polymer compositions through a multi-layer die, followed by immediate cooling and winding. This eliminates intermediate handling, reduces process complexity, and minimizes residual solvent content by avoiding repeated heating and cooling cycles associated with discrete lamination and coating steps.
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 enhances productivity and performance by maintaining initial sorbability and porosity of sorbent materials, achieving superior adhesion and mechanical strength, and reducing residual solvents, resulting in membranes with improved sorption kinetics and permselectivity.
Implementation Method 1
Flat-film polymeric membranes can be manufactured by the method of thermally induced phase separation (TIPS)
Implementation Method 2
extracting the diluent from the multilayer film with an extractant
Data Source
AI summary
Provided is a novel continuous single-step method of manufacturing a multilayer sorbent polymeric membrane having superior productivity, properties and performance. At least one layer of the polymeric membrane comprises sorbent materials and a plurality of interconnecting pores. The method includes: (a) coextruding layer-forming compositions to form a multilayer coextrudate; (b) casting the coextrudate into a film; (c) extracting the film with an extractant; and (d) removing the extractant from the extracted film to form the multilayer sorbent polymeric membrane. The sorbent membrane of this disclosure can find a wide range of applications for use in filtration, separation and purification of gases and fluids, CO2 and volatile capture, structural support, vehicle emission control, energy harvesting and storage, electrolyte batteries, device, protection, permeation, packaging, printing, and etc.