Filter media comprising a pre-filter layer and related components, systems, and methods associated therewith are provided. In some embodiments, the pre-filter layer may be designed to impart desirable properties to the filter media, such as a high gamma and/or long service life, while having relatively minimal or no adverse effects on another property of the filter media that is important for a given application. For instance, a pre-filter layer may be used to improve the upstream removal of fine particulate matter, which may clog a downstream efficiency layer comprising submicron fibers and reduce filtration performance. The pre-filter layer may be configured to increase service life and/or increase the gamma of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

A multi-layered filter medium with a densified layer made of synthetic fibers is useful for filtering liquids. A method for its production involves providing multiple layers, densifying a layer, and joining the multiple layers.

A blended polymer comprising, an amorphous thermoplastic polymer and a thermoplastic semi-crystalline polymer, each of the polymers being essentially miscible in the other and being blended at a weight ratio of amorphous polymer/semi-crystalline polymer of greater that 0.05 to about 20 forms a melt blown nonwoven fabric having essentially no defects with long fiber lengths having uniform diameters. The nonwoven fabrics when used as a filter may have greater than 95% efficiency at a pressure drop of less than 2 mm Hg even after being exposed to high temperatures (˜70° C.) for an hour or more.

The invention discloses a fiber filament non-woven fabric with a small pore size and a large porosity, which adopts an island type ultra-fine fiber single filament, which is juxtaposed into an unidirectional silk layer several times, and a thin strip-shaped liquid is applied laterally on the unidirectional silk layer. The resin adhesive liquid bonds and fixes all the silk layers into a unidirectional non-woven fabric fixed in a grid segment. The unidirectional non-woven fabric is covered with meltblown non-woven fabric on one or both sides to make a filter material that can 100% filter viruses, bacteria, and micro-particles smaller than PM2.5. It can also be used for a wider range of filter materials, thermal insulation materials, oil absorption materials, battery separator materials, medical and health materials, environmental protection materials, clothing materials, wiping materials.

Disclosed are a blood filter which exhibits excellent leukocyte elimination performance as well as significantly improved blood throughput per unit time and erythrocyte recovery rate and a method of manufacturing the same. The blood filter of the present invention includes a pre-treatment filter which is a laminate of first non-woven fabrics having a mean fiber diameter of 5 to 30 μm and a mean pore size of 10 to 30 μm, and a main filter which is a laminate of second non-woven fabrics having a mean fiber diameter of 1 to 5 μm, a mean pore size of 5 to 10 μm and a mean pore size distribution rate of 30% or more. A filling density of the pre-treatment filter and a filling density of the main filter, with respect to a target blood throughput of the blood filter, are 0.1 g/100 ml to 1 g/100 ml and 1 g/100 ml to 3 g/100 ml, respectively.

An AM/AV fabric comprising base fibers comprising a base polymer composition and AM/AV fibers comprising an AM/AV polymer composition comprising an AM/AV polymer and an AM/AV compound. The base fibers and the AM/AV fibers are intermingled with one another; and the fabric demonstrates an Escherichia coli efficacy log reduction greater than 4.0, as measured in accordance with ASTM E3160 (2018) and a particle filtration efficiency greater than 35%.

Nonwoven fabrics are provided that include (i) a plurality of continuous matrix fibers comprising a first polymeric material having a first melting point and including a first polymer component, in which the first polymer component comprises a first recycled-polyester, and (ii) a plurality of binder fibers having an irregular cross-section randomly dispersed throughout the plurality of matrix fibers, in which the plurality of binder fibers comprising a second polymeric material having a second melting point including a second polymer component. The second melting point being less than the first melting point.

Use of an electrically charged nonwoven fabric that is made of a fiber predominantly composed of an amorphous polymer provides a novel filtration material having improved performance compared to that of conventional filtration materials, and having excellent heat resistance and excellent flame retardancy as well as an electrically charged nonwoven fabric for use in the filtration material. It is preferable that the surface charge density is greater than or equal to 1×10.sup.−10 coulomb/cm.sup.2. It is preferable that the collection efficiency for collecting a dust particle with a particle diameter of 1 μm flowing at a fabric-passing velocity of 8.6 cm/second is greater than or equal to 40%, the QF value is greater than or equal to 0.05, and the decrement of the dust-particle collection efficiency after being allowed to leave at 100° C. for 24 hours is less than or equal to 10%.

Embodiments of the present disclosure generally relate to coated substrates having, e.g., anti-viral properties, to articles including the coated substrates, and to processes for making such coated substrates and articles. In an embodiment, a mask for preventing infection by a virus is provided. The mask includes a coated substrate having a breathing resistance (95 L/min, EN 149:2001) of about 6 mbar or less and a water droplet absorption time of less than about 5 seconds. The coated substrate includes a non-woven fabric having a weight of about 120 g/m.sup.2 or less according to ASTM D3776, and mineral oxide particles, iron oxide particles, or both, coupled to at least a portion of the non-woven fabric.

A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The second film is downstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 μm when air containing the particles is passed hrough at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. The PF value={−log((100−collection efficiency (%))/100)}/(pressure drop (Pa)/1000). A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be used in a filter pack or filter unit, and may be produced by integrating the first and second films and the pre-collection member using heat lamination.