The present invention relates to the field of air filtration, in particular to a polytetrafluoroethylene composite filter material and a preparation method and uses thereof. The polytetrafluoroethylene composite filter material comprises a support layer and a polytetrafluoroethylene microporous membrane layer, and the support layer and the polytetrafluoroethylene microporous membrane layer are compounded by an adhesive, wherein the adhesive comprises a two-component polyurethane adhesive, a pore forming agent and an inorganic filler. The present invention adopts a two-component solvent-free polyurethane adhesive, and by adding a low-temperature pore forming agent and an inorganic filler, the pore forming agent forms an irregular pore channel structure at the bonding interface during curing, and the inorganic filler prevents the adhesive from entering the micropores of the polytetrafluoroethylene membrane, so that the air permeability and filtration efficiency of the polytetrafluoroethylene microporous membrane are not affected after compounding; and the prepared polytetrafluoroethylene composite filter material has good air permeability, high peel strength, good filtration efficiency and good barrier effect.

The present invention relates to the field of air filtration, in particular to a polytetrafluoroethylene composite filter material. The polytetrafluoroethylene composite filter material comprises a supporting layer and a polytetrafluoroethylene film layer, wherein the supporting layer is a silver-plated carbon nanomaterial-modified meltblown nonwoven fabric. The polytetrafluoroethylene composite filter material is prepared by fiberizing a resin material modified by silver-plated carbon nanomaterial on the surface of a polytetrafluoroethylene film by a melt-blowing method. The polytetrafluoroethylene composite filter material of the present invention combines filtering and sterilizing functions, has higher filtering efficiency and filtering precision, has the functions of sterilizing and killing viruses, has a good isolation effect, and greatly prolongs the service life of the filter material.

The present invention relates to the field of air filtration, in particular to a polytetrafluoroethylene composite filter material. The polytetrafluoroethylene composite filter material comprises a supporting layer and a polytetrafluoroethylene film layer, wherein the supporting layer is a silver-plated carbon nanomaterial-modified meltblown nonwoven fabric. The polytetrafluoroethylene composite filter material is prepared by fiberizing a resin material modified by silver-plated carbon nanomaterial on the surface of a polytetrafluoroethylene film by a melt-blowing method. The polytetrafluoroethylene composite filter material of the present invention combines filtering and sterilizing functions, has higher filtering efficiency and filtering precision, has the functions of sterilizing and killing viruses, has a good isolation effect, and greatly prolongs the service life of the filter material.

A provided stretched porous polytetrafluoroethylene membrane has an air permeability of 4 cm.sup.3/(sec.Math.cm.sup.2) or more, as expressed in terms of Frazier air permeability, in a thickness direction, and has a total cohesion of 1.9 (N/20 mm).sup.2 or more, the total cohesion being expressed by a product of a peel cohesion in a first in-plane direction and a peel cohesion in a second in-plane direction perpendicular to the first direction. The above stretched porous membrane is highly air-permeable and, for example, when included in a filter member, being less likely to suffer breakage at the time of handling the member or placing the member on a housing or the like.

A spunbond non-woven fabric includes a nonbonded projected part and a bonded recessed part. Bending resistance in a machine direction of the spunbond non-woven fabric is 20 mN or more and 40 mN or less, and in a non-woven fabric cross-section, a thickness from one surface to another surface of the projected part is determined to be t.sub.A, a thickness from one surface to another surface of the recessed part is determined to be t.sub.B, and respective distances from one surface of the projected part to one surface of the recessed part are determined to be t.sub.C and to (t.sub.C<t.sub.D), and the spunbond non-woven fabric has a relation represented by formulas (1) and (2) below:

0.5≤1−t.sub.B/t.sub.A<1.0  (1)

0.35<t.sub.C/t.sub.D<0.65  (2).

Provided is a porous polytetrafluoroethylene membrane in which an absolute value of a difference in lightness between one principal surface and the other principal surface is 1.0 or more, where the lightness is lightness L* of CIE 1976 (L*, a*, b*) color space specified in JIS Z8781-4: 2013. The porous polytetrafluoroethylene membrane may be colored black or gray. The porous polytetrafluoroethylene membrane provided can have properties with a reduced coloring-induced deterioration.

The present invention provides devices and methods to capture airborne agents, microbes, including viruses, and microbial antigens, toxins and allergens and prevent the spread of infection from direct contact with contaminated surfaces (contact contamination), from large droplets of infectious material that fall out of the air, or from small droplets that can be carried by the air stream throughout the environment (airborne contamination).

Disclosed herein are phase separator devices, and related methods of fabrication and use. The disclosure provides improved phase separator devices for phase separation of input feeds, and systems/methods for utilizing and fabricating the devices. The disclosure provides phase separator devices utilizing inertial separation and porous media extraction for the phase separation of two-phase input feeds (e.g., to separate an input feed of a two-phase mixture to a first phase output (e.g., to a liquid output flow) and to a second phase output (e.g., to a gas output flow)). The device can separate a mixed fluid flow of both liquid and gases. The liquid and gas can include liquid and vapor phases of the same chemical/constituent (e.g., ammonia), or may include liquid and gases of two different constituents (e.g., liquid water and air). The phase separator devices can be utilized at standard gravity to micro-gravity to zero gravity environments.

Devices, systems and methods are disclosed which relate to using a wet foam elution method for removal of particles from a flat filter. Particles are captured from the atmosphere onto the flat filter. The flat filter is then placed into an extractor which passes a stream of wet foam through the flat filter. Expansion of the foam works to efficiently remove captured particles. The foam flows from the filter along with the captured particles into a sample container. Once in the sample container, the foam quickly breaks down leaving an analysis ready liquid sample.

A device for preventing contamination of a positive-pressure connector (6) of an indwelling needle and a method based on same. The device comprises a shell (1), a connecting port (3) fixedly connected to the shell (1) and used for connecting to the positive-pressure connector (6), an air pressure balance hole (5) disposed opposite to the connecting port (3) and provided on the shell (1), and a filtering membrane (2) provided between the air pressure balance hole (5) and the connecting port (3). The device is simple in structure, adopts a structural design of the filtering membrane (2), can filter microorganisms, bacteria, viruses, dusts, and particulate pollution sources, and is used during indwelling of infusion intervals to prevent the positive-pressure connector (6) from being exposed to the air and maintain the aseptic state and positive-pressure condition of the positive-pressure connector (6) during indwelling.