The invention relates to a respirator mask comprising a filter material piece made of an air-permeable material and at least one securing band, wherein the air-permeable material comprises at least one layer of a non-woven fabric and the at least one securing band is designed to secure the respirator mask to the head, wherein the air-permeable material and the at least one securing band are made of the same plastic material.

A pleated multilayer air filter assembly including a primary filtration layer and a prefilter layer that are bonded to each other and are co-pleated with each other. The primary filtration layer includes meltblown electret fibers. The prefilter layer includes meltspun, spunbonded electret fibers that comprise a radially outer surface comprising polymethylpentene. The ratio of Effective Fiber Diameter of the fibers of the primary filtration layer to Effective Fiber Diameter of the fibers of the primary filtration layer is at least 1.5.

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).

A filter for filtering particulates from a fluid stream includes a filter element, a first end cap, a second end cap, and a wrap. The end caps are respectively secured to the ends of the filter element to form a fluid tight seal therebetween. At least one of the end caps defines an opening therethrough in fluid communication with the interior passage of the filter element. The wrap is in the form of a strip secured to at least the filter element. The wrap comprises a conductive layer comprising an electrically-conductive material. The wrap is wrapped around the filter element such that at least forty percent of the outer surface area is covered by the conductive layer.

The present invention provides a depth filter which contains fine particles and coarse particles, and which exhibits excellent filtration precision with respect to a high concentration fluid and/or a high viscosity fluid. This depth filter enables filtration for a long period of time, while maintaining a low filtration pressure.

The present invention is a depth filter which is obtained by winding a fiber sheet into a cylinder, and which comprises a pre-filtration layer and a microfiltration layer; the pre-filtration layer and the microfiltration layer are formed of a fiber sheet; the fiber sheet is composed of a nonwoven fabric or a web; the average fiber diameter of the fiber sheet continuously decreases from the pre-filtration layer toward the microfiltration layer; and the average weight per square meter of the fiber sheet continuously decreases from the pre-filtration layer toward the microfiltration layer.

A provided stretched porous polytetrafluoroethylene membrane has a node-fibril structure including a plurality of nodes and a fibril connecting the plurality of nodes. A ratio of an average length of the plurality of nodes in a thickness direction of the stretched porous polytetrafluoroethylene membrane to a thickness of the stretched porous polytetrafluoroethylene membrane is 10% or more. The above stretched porous polytetrafluoroethylene membrane is less likely to suffer breakage. In the above stretched porous polytetrafluoroethylene membrane, assuming that there is a cuboid region having an upper surface and a lower surface respectively positioned at one membrane surface and the other membrane surface of the stretched porous polytetrafluoroethylene membrane, the number of the nodes included in the region may be 4 or less per micrometer thickness, the upper surface and the lower surface each having dimensions of 280 μm×280 μm.

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.

A multi-functional air purification filter includes: a breathable support layer; a mesh layer provided on the breathable support layer; and a filter layer provided on the mesh layer, wherein at least a portion of the multi-functional air purification filter has a plurality of bends, and the mesh layer includes a coating layer of at least one of a photocatalytic material, an adsorption material, or a sterilizing material.

Provided is an internal pressure adjustment member to be attached to an outer surface of a housing, the member having high air permeability even when a differential pressure that can be generated between the inside and the outside of a housing to which the internal pressure adjustment member is attached is small, and inhibiting damage to the member and a reduction in the air permeability of the member due to coming soil and mud. The internal pressure adjustment member includes: a filter portion including a net-like or mesh-like support layer and first and second porous polytetrafluoroethylene (PTFE) membranes laminated on the support layer such that the support layer is interposed therebetween, the first porous PTFE membrane being exposed on one surface of the filter portion, the second porous PTFE membrane being exposed on another surface of the filter portion; and an adhesive portion, formed on the one surface of the filter portion, for attaching the filter portion to the outer surface of the housing. The first porous PTFE membrane and the second porous PTFE membrane each have an average pore diameter of 2.0 μm or more, the filter portion has a thickness of 140 μm or less, and the filter portion has a density of 0.60 g/cm.sup.3 or less.

The disclosure relates to a mask including a perforated exterior shell sized to cover the nose and mouth of a user and constructed of one or more fabric layers, and a removable multi-layer nonwoven fabric insert sized to cover the nose and mouth of a user and adapted for abutting contact with the exterior shell, the nonwoven fabric including a layer of a spunbond material and a layer of meltblown material adjacent to the layer of spunbond material.