The present invention addresses the problem of providing a separating membrane mainly comprising a thermoplastic resin having high permeability. The present invention relates to a separating membrane including a thermoplastic resin, wherein the width of voids in the separating membrane is at least equal to 1 nm and at most equal to 1000 nm, and the curvature rate of the voids is at least equal to 1.0 and at most equal to 6.0.

The present invention addresses the problem of providing a separating membrane mainly comprising a thermoplastic resin having high permeability. The present invention relates to a separating membrane including a thermoplastic resin, wherein the width of voids in the separating membrane is at least equal to 1 nm and at most equal to 1000 nm, and the curvature rate of the voids is at least equal to 1.0 and at most equal to 6.0.

The purpose of the present invention is to provide: a separation film that consists primarily of a cellulose ester and has a high membrane strength and a high elongation degree; and a production method therefor. Provided is a separation film which has a structure comprising a cellulose ester phase and pores, wherein the average pore diameter R is 0.001-6 m, the value obtained from the expression: breaking strength (MPa)(100porosity (%))100 is 40 or greater, and the elongation degree is 10% or greater.

The purpose of the present invention is to provide: a separation film that consists primarily of a cellulose ester and has a high membrane strength and a high elongation degree; and a production method therefor. Provided is a separation film which has a structure comprising a cellulose ester phase and pores, wherein the average pore diameter R is 0.001-6 m, the value obtained from the expression: breaking strength (MPa)(100porosity (%))100 is 40 or greater, and the elongation degree is 10% or greater.

A cellulose ester, wherein, in a structural formula of the following general formula (I), a degree of substitution where X is an acyl group is from 2.91 to 3.0; the acyl group includes benzoyl group (A) optionally having a substituent, and benzoyl group (B) optionally having a substituent different from that of benzoyl group (A); and when the degree of substitution is 3.0, a degree of substitution of benzoyl group (A) is from 1.5 to 2.9, and a degree of substitution of benzoyl group (B) is from 0.1 to 1.5,

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wherein all or some of X represents an acyl group; when some of X represents an acyl group, the remainder represents a group selected from a hydrogen atom and an alkyl group; and n represents an integer of from 20 to 20,000.

A cellulose ester, wherein, in a structural formula of the following general formula (I), a degree of substitution where X is an acyl group is from 2.91 to 3.0; the acyl group includes benzoyl group (A) optionally having a substituent, and benzoyl group (B) optionally having a substituent different from that of benzoyl group (A); and when the degree of substitution is 3.0, a degree of substitution of benzoyl group (A) is from 1.5 to 2.9, and a degree of substitution of benzoyl group (B) is from 0.1 to 1.5,

##STR00001##

wherein all or some of X represents an acyl group; when some of X represents an acyl group, the remainder represents a group selected from a hydrogen atom and an alkyl group; and n represents an integer of from 20 to 20,000.

Provided is a semipermeable membrane having a high chlorine resistance.

The semipermeable membrane is formed of a cellulose ester, the cellulose ester having an optionally substituted benzoyl group.

The problem to be solved by the present invention is to provide a separation film mainly comprising a cellulose-based resin having high permeability. The present invention pertains to a separation film containing a cellulose ester, wherein the separation film is provided with a bicontinuous structure comprising voids and phases containing the cellulose ester, and the width of the voids is 1 to 200 nm inclusive.

The problem to be solved by the present invention is to provide a separation film mainly comprising a cellulose-based resin having high permeability. The present invention pertains to a separation film containing a cellulose ester, wherein the separation film is provided with a bicontinuous structure comprising voids and phases containing the cellulose ester, and the width of the voids is 1 to 200 nm inclusive.

Provided is a simple method for producing a cell concentrate (other than human blood) in a short time with neither loss of cells nor an excessive burden on cells. Included is a method for producing a cell concentrate using an inside-out filtration system for processing a cell suspension, the system including: a cell suspension inlet port; a filtrate outlet port; a cell suspension outlet port; and hollow fiber separation membranes provided between the cell suspension inlet port and the cell suspension outlet port, wherein the membranes have a total cross-sectional area of 0.5-1.5 cm.sup.2, the membranes have an inside membrane area of 0.2 m.sup.2 or less, the suspension is flowed inside the membranes at a linear velocity of 500-1200 cm/min, and the quotient of the division of the initial filtrate flow rate from the filtrate outlet port by the flow rate into the cell suspension inlet port is 0.4-0.7.