초록 ▼

Process for producing integrally asymmetrical hydrophobic polyolefinic membranes with a separation layer, in particular for gas exchange, via thermally induced liquid-liquid phase separation. A solution of at least one polyolefin in a solvent system containing a compound A and a compound B is extrud

Process for producing integrally asymmetrical hydrophobic polyolefinic membranes with a separation layer, in particular for gas exchange, via thermally induced liquid-liquid phase separation. A solution of at least one polyolefin in a solvent system containing a compound A and a compound B is extruded to form a shaped object. Compound A is a strong solvent and compound B a weak non-solvent for the polymer. After leaving the die, the shaped object is cooled using a solid or liquid cooling medium, which does not dissolve the polymer and does not react chemically with it, until the phase separation and solidification of the high-polymer-content phase take place. The integrally asymmetrical membrane producible in this manner has a porosity of greater than 30% to 75% by volume, a sponge-like, open-pored, microporous support layer without macrovoids and on average isotropic pores, a separation layer on at least one of its surfaces with pores <100 nm, if any, and a gas separation factor .alpha.(CO2/N2) of at least 1. The membrane is preferably used for blood oxygenation.

대표청구항 ▼

1. Hydrophobic integrally asymmetrical membrane comprising: at least one polyolefin polymer; wherein the membrane comprises a support layer having a sponge-like, open-pored, microporous structure and, adjacent at least one of a first surface and a second surface of the support layer, a separation la

1. Hydrophobic integrally asymmetrical membrane comprising: at least one polyolefin polymer; wherein the membrane comprises a support layer having a sponge-like, open-pored, microporous structure and, adjacent at least one of a first surface and a second surface of the support layer, a separation layer with denser structure; wherein the separation layer optionally has pores with an average diameter <100 nm; wherein the support layer is free of macrovoids and the pores in the support layer are on average substantially isotropic; and wherein the membrane has a porosity in the range from greater than 30% to less than 75% by volume and a gas separation factor .alpha.(CO2/N2) of at least 1.