Multilayered Ultrafiltration Membrane Cocasting

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Solution Overview

Problem

Current membrane technologies face challenges in producing multilayered composite membranes with dissimilar ultrafiltration and microporous layers, as they require separate manufacturing processes, are prone to deformation, and have inefficiencies in handling thin layers, leading to flow and concentration non-uniformities.

Innovation Solution

The development of an integral multilayer flat sheet membrane made from multiple polymer solutions, where at least one layer is an ultrafiltration membrane, using a cocasting process to form a multilayered liquid sheet and immersing it into a coagulation bath for phase separation, allowing for a gradient of pore sizes between layers and improved retentive behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If separate manufacturing processes are used for ultrafiltration and microporous layers, then each layer can be optimized independently, but the overall membrane structure becomes complex and handling becomes difficult

Engineering Contradiction:

Improvelayer optimizationVSAvoidmembrane structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple ultrafiltration layers with different pore sizes into a single integrated membrane structure using a support layer. This merging approach maintains the optimization benefits of having different pore size layers while simplifying the overall structure into a unified composite membrane that is easier to manufacture and handle as a single unit.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite material structure consisting of a support layer made from one polymer solution and ultrafiltration layers made from different polymer solutions with distinct pore sizes. This composite approach allows each layer to be optimized for its specific function while maintaining structural integrity through the composite architecture.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If thin layers are used to achieve better separation, then separation efficiency improves, but handling becomes inefficient and deformation occurs

Engineering Contradiction:

Improveseparation efficiencyVSAvoidhandling efficiency

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The membrane is segmented into multiple functional layers with different thicknesses optimized for their specific roles. The support layer provides mechanical strength and can be thicker, while the ultrafiltration layers can be thinner for separation efficiency. This segmentation allows each layer to be optimized independently without compromising the overall membrane's handling properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the membrane have different properties - the support layer has higher mechanical strength and can be thicker for durability, while the ultrafiltration layers have optimized pore structures for separation. This local quality variation allows thin separation layers to be used where needed without compromising overall membrane integrity and handling.

Inventive Principle:

Principle #3Local quality

3Reliability

If multiple layers with different pore sizes are combined, then viral particle removal improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveviral particle removalVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The support layer is formed first as a foundation, providing a stable base onto which the ultrafiltration layers are subsequently applied. This preliminary action of creating the support structure first simplifies the overall manufacturing process by establishing a framework that guides subsequent layer formation and ensures proper adhesion and alignment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The manufacturing process utilizes parameter changes in the polymer solutions, including viscosity adjustments and phase inversion conditions, to control layer formation. By manipulating these parameters, the process achieves controlled formation of multiple layers with different pore sizes without requiring excessively complex manufacturing equipment or procedures.

Inventive Principle:

Principle #35Parameter changes

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 approach results in membranes with enhanced properties, such as improved viral particle removal and extended filter life, by distributing particles diffusely throughout the membrane thickness, reducing pore plugging and maintaining high flux and durability.

Implementation Method 1

immersing the sheet into a coagulation bath to effect phase separation and form a porous membrane

Methodology Applied

Scientific EffectPhase separation: Phase Change

Data Source

PatentUS10751669B2Ultrafiltration membranes and methods of making

Publication Date: 2020.08.25 EMD MILLIPORE CORP

AI summary

The present invention is an integral multilayered composite membrane having at least one ultrafiltration layer made by cocasting or sequentially casting a plurality of polymer solutions onto a support to form a multilayered liquid sheet and immersing the sheet into a liquid coagulation bath to effect phase separation and form a multilayered composite membrane having at least one ultrafiltration layer.