A separation membrane has high strength and low leakage property while maintaining high gas permeability using poly(4-methyl-1-pentene) excellent in chemical resistance and gas permeability. The separation membrane contains poly(4-methyl-1-pentene) as a main component, in which a ratio RA of a rigid amorphous of poly(4-methyl-1-pentene) in the separation membrane is 43% or more and 60% or less, a porosity is 30% or more and 70% or less, and a dense layer is provided on at least one surface.

The present disclosure discloses a device for biaxially-oriented stretching polytetrafluoroethylene hollow fiber membranes and the method thereof. The device may include a lubricant removing oven and a tube blank heating oven mounted at the outlet end of the push-compression mold, a core extension extending from the core into the lubricant removing oven and the tube blank heating oven, and a speed regulating guide wheel mounted at the outlet of the tube blank heating oven. A tube blank is extruded from a push-compression machine, inserted on the core extension for removal of lubricant in the lubricant removing oven, heated in the tube blank heating oven, transversely stretched by means of the bulked core, and then wound onto the speed regulating guide wheel for longitudinal stretching. Both transverse and longitudinal stretching can be realized for polytetrafluoroethylene tube blanks, overcoming disadvantages of traditional processing devices that can merely perform longitudinal stretching.

A method for producing a microporous material comprising the steps of: providing an ultrahigh molecular weight polyethylene (UHMWPE); providing a filler, providing a processing plasticizer, adding the filler to the UHMWPE in a mixture being in the range of from about 1:9 to about 15:1 filler to UHMWPE by weight; adding the processing plasticizer to the mixture; extruding the mixture to form a sheet from the mixture; calendering the sheet; extracting the processing plasticizer from the sheet to produce a matrix comprising UHMWPE and the filler distributed throughout the matrix; stretching the microporous material in at least one direction to a stretch ratio of at least about 1.5 to produce a stretched microporous matrix; and subsequently calendering the stretched microporous matrix to produce a microporous material which exhibits improved physical and dimensional stability properties over the stretched microporous matrix.

An object of the present invention is to provide a porous hollow-fiber membrane satisfying both high strength and high pure-water permeation performance and at the same time, having high bending resistance. The present invention relates to a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane and when a photograph of a cross-section parallel to the longitudinal direction of the porous hollow-fiber membrane is binarized into a structure portion and a void portion, the following 1) and 2) are satisfied: 1) a proportion of an area of the void portion is from 20 to 50%, and 2) a value obtained by dividing a total of peripheral lengths of the void portions by a total of areas of the void portions is 2.0 ?m.sup.?1 or less.

Provided is a manufacturing method of a polyolefin-based multilayer composite porous film, including: a) forming a composition including a polyolefin resin and diluent to a sheet; b) stretching the sheet and extracting the diluent to manufacture a film; c) performing heat-treatment on the manufactured film; and d) coating one surface or both surfaces of the heat-treated film with a coating solution containing a heat resistant resin, wherein step c) and step d) are continuously performed.

Micro- and nanofilters with precision pore sizes and pore layout have applications in many fields including capturing circulating tumor cells and fetal cells in blood, water treatment, pathogen detection in water, etc. Methods to fabricate micro- and nanofilters not using track etching or reactive ion etching are provided, allowing easy fabrication of single layer or stack of films simultaneously, and/or stack of films on rolls. Microfilter can be made using one or more layers of material. Invention enables mass production of microfilters with lithographic quality at low cost. Isolation, enumeration and characterization of circulating tumor cells using microfilters provides (i) guides to cancer treatment selection and personalize dosage, (ii) low cost monitoring for treatment response, disease progression and recurrence, (iii) assessment of pharmacodynamic effects, (iv) information on mechanisms of resistance to therapy, and (v) cancer staging. Microfabrication methods are also applicable to fabrication of any free standing patterned polymeric films.

The present invention provides a hollow fiber membrane module that can effectively resolve the accumulation of suspended solids within the membrane module, lower running costs, and also operate stably. The present invention relates to a hollow fiber membrane molecule provided with: a cylindrical case having a first end and a second end in the direction of height; a plurality of hollow fiber membranes accommodated within the cylindrical case; and a first potting part accommodated within the cylindrical case and attaching the plurality of hollow fiber membranes together such that the end parts of the plurality of hollow membrane fibers at a first end side of the cylindrical case are open. The hollow fiber membranes are porous hollow fiber membranes having a breaking strength of 23 MPa, and the hollow membrane module has a membrane area per unit volume of 800-3700 m.sup.2/m.sup.3. The filling fraction for the hollow fiber membranes in a cross-section orthogonal to the direction of height of the cylindrical case is 25-38%.

The present invention provides a porous hollow fiber membrane that has both high strength and high pure water permeability, and that exhibits excellent thermal deformation resistance. The present invention is related to a porous hollow fiber membrane containing a fluororesin-based polymer, and a manufacturing method of the membrane comprises a drawing step and a relaxing step. The porous hollow fiber membrane is characterized in that: the molecular chain of the polymer is oriented in the longitudinal direction of the hollow fiber membrane; and at the same time internal distortion of oriented non-crystalline chains, which is disadvantageous in terms of entropy, is alleviated.

A film-stretching apparatus in accordance with an aspect of the present invention includes a stretching furnace which has (i) an entrance through which a material film is transferred into the stretching furnace and (ii) an exit through which the material film having been stretched is transferred out of the stretching furnace, an airflow in the entrance being controlled so as to be directed toward an outside of the stretching furnace.

Disclosed herein is filtration material having expanded polytetrafluoroethylene (ePTFE) and method of making. The method comprises expanding polytetrafluoroethylene in a machine direction orienter (MDO) and expanding or stretching to a ratio from about 20:1 up to about 100:1. The sheet of polytetrafluoroethylene is then relaxed. Upon relaxing the sheet of polytetrafluoroethylene, the sheet of polytetrafluoroethylene is fed into a transverse direction orienter (TDO). The temperature of the sheet of polytetrafluoroethylene in TDO is maintained to remain below 200? C. The sheet of polytetrafluoroethylene is then expanded or stretched to a ratio from about 1.5:1 up to about 100:1, with the TDO, thus providing the expanded polytetrafluoroethylene of the present disclosure having increased tensile strength and finer filaments.