Separation membrane and method for producing same

JPWO2024043218A5Pending Publication Date: 2026-06-15
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Applications
Filing Date
2023-08-22
Publication Date
2026-06-15

AI Technical Summary

⚠Technical Problem

Conventional methods for producing gas separation membranes using polyolefin polymers fail to achieve a balance between high gas permeability and sufficient solvent resistance, often due to insufficient formation of lamellar crystals on the membrane surface, leading to either poor permeability or poor solvent resistance.

⚗Method used

A separation membrane composed primarily of poly(4-methyl-1-pentene) with a surface layer containing accumulated lamellar crystals and micropores, which provides both high gas permeability and improved solvent resistance, is developed. The membrane has a porosity of 0.1% to 10% and average pore diameters of 3 to 30 nm, with a crystallinity of 5% to 35% and an area ratio of lamellar crystals between 10% to 60% on the surface.

🎯Benefits of technology

The membrane exhibits high gas permeability, as measured by a permeability of 1000 GPU or more, while maintaining effective solvent resistance, even after immersion in organic solvents, thereby addressing the limitations of previous technologies.

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Abstract

A separation membrane is used in deaeration methods for removing a gas dissolved in a liquid, and gas exchange methods for exchanging a gas dissolved in a liquid and a gas component in a gas phase. The present invention provides a separation membrane that has solvent resistance and maintains high gas permeability performance by using poly(4-methyl-1-pentene), which excels in solvent resistance and gas permeability. The separation membrane contains poly(4-methyl-1-pentene) as a main component, and includes surface layers and an inner layer. At least one of the surface layers includes lamella crystals, and the surface layer including the lamella crystals has micropores. Defining porosity as the percentage of micropores in the membrane surface with the membrane surface being 100%, the porosity is 0.1% to 10%. The average pore diameter of the micropores is 3 nm to 30 nm.
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