Porous Membrane Pore Uniformity Resin Composition
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Solution Overview
Problem
Existing porous membrane production methods result in hydrophobic membranes, complex production processes, and variations in quality due to white turbidity issues, leading to suboptimal fractionation performance and water permeability.
Innovation Solution
A resin composition comprising a membrane-forming polymer, a polymer obtained by polymerizing a (meth)acrylic acid ester macromonomer, and a vinylpyrrolidone unit, which forms a porous membrane with suppressed large pore formation, high uniformity, and excellent transparency, suitable for water treatment applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a hydrophilic macromolecule such as polyvinylpyrrolidone (PVP) is contained as a pore forming agent and then removed, then porous structure is formed, but the membrane becomes hydrophobic and the production process becomes complicated
Solution Approach 1:
The patent extracts the hydrophilic macromolecule (PVP) from the membrane system after it has served its purpose as a pore-forming agent. The PVP is completely removed through extraction with water or water-soluble solvents, creating permanent pores without requiring cross-linking or leaving residual material, thus simplifying the production process while maintaining porosity.
Solution Approach 2:
The patent creates a porous membrane structure by using PVP as a sacrificial pore-forming agent during membrane formation, then completely removing it to leave behind a porous network. This approach achieves high porosity (30-80%) with uniform pore distribution without requiring additional cross-linking steps or leaving hydrophobic residues.
2Reliability
If a graft copolymer or random copolymer of vinylpyrrolidone and (meth)acrylate is used to make the hydrophilic component insoluble, then hydrophilicity is achieved, but white turbidity occurs and uniformity decreases
Solution Approach 1:
The patent uses PVP as a temporary, disposable pore-forming agent that is completely removed after membrane formation. This approach avoids the need for complex copolymer structures designed to be insoluble, eliminating the white turbidity problem and ensuring uniform membrane quality while maintaining hydrophilicity through the porous structure itself.
Solution Approach 2:
The patent uses PVP as an intermediary substance during membrane formation that facilitates pore creation but is then completely removed. This intermediary approach avoids the need for permanent hydrophilic copolymer structures that cause uniformity issues, achieving both hydrophilicity and uniformity through temporary mediation.
3Reliability
If polyvinylpyrrolidone is cross-linked to immobilize it, then hydrophilicity is maintained, but the production process becomes complicated and small amounts of PVP remain in the membrane
Solution Approach 1:
Instead of cross-linking PVP to immobilize it, the patent completely extracts and removes PVP from the membrane system after it has formed the desired porous structure. This extraction process uses water or water-soluble solvents to dissolve and remove all PVP residues, eliminating the need for cross-linking steps and ensuring complete removal without leaving small amounts in the membrane.
4Productivity
If the membrane has high porosity for water permeability, then water permeability increases, but large pores of 1 μm or more may form reducing fractionation performance
Solution Approach 1:
The patent achieves local quality control by creating a uniform distribution of PVP particles throughout the membrane matrix before formation. This ensures that after PVP removal, the resulting pores are uniformly distributed and sized throughout the membrane, preventing localized formation of large pores while maintaining high overall porosity for water permeability.
Solution Approach 2:
The patent controls pore size uniformity by adjusting parameters such as PVP concentration, molecular weight, and membrane formation conditions. By optimizing these parameters, the patent achieves a balance between high porosity (for water permeability) and uniform pore sizing (to prevent large pore formation that would reduce fractionation performance).
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 solution achieves a porous membrane with favorable fractionation performance and high water permeability, ensuring consistent quality and transparency, suitable for use in hollow fiber membranes, electrolyte supports, and water treatment devices.
Implementation Method 1
a polymer containing a vinylpyrrolidone unit... high uniform pores... favorable fractionation performance
Implementation Method 2
membrane-forming stock solution... porous membrane... suppressed large pore formation
Data Source
AI summary
The present invention pertains to a resin composition which includes component: a membrane-forming polymer, component: a polymer obtained by polymerizing a monomer composition which includes a (meth)acrylic ester macromonomer represented by general formula and another monomer, and component: a polymer including a vinylpyrrolidone unit, a membrane-forming stock solution which includes the resin composition, a porous membrane obtained by forming with the membrane-forming stock solution, and a hollow fiber membrane, a water treatment device, an electrolyte support, and a separator which use the porous membrane. According to the present invention, it is possible to provide a porous membrane which has pores with high uniformity wherein the formation of large pores with a diameter of 1 μm or higher is suppressed and which has excellent fractionation performance and high water permeability, and a hollow fiber membrane, water treatment device, electrolyte support, and separator which use the porous membrane.