This disclosure describes a filtration medium that is preferably glass-free or substantially glass-free. In some embodiments, the filtration medium preferably exhibits capacity and efficiency comparable to or better than similar glass-containing filtration media. The filtration medium includes bicomponent fibers, efficiency fibers (for example, PET fibers), and microfibrillated fibers. The efficiency fibers include fibers having a fiber diameter in a range of 1 micron to 5 microns and fibers having a fiber diameter of at least 0.1 micron and less than 1 micron.

The invention relates to a method for recycling respiratory protection masks comprising a plurality of layers manufactured from a single thermoplastic polymer chosen from polypropylene, polyethylene terephthalate, polylactic acid, homopolymers and copolymers of polyamide 6 (PA6) and long-chain polyamides such as PA11 or PA12, and comprising a filtration layer made of polyvinylidene fluoride.

A filter medium is disclosed having a nonwoven layer, which has bicomponent fibres, and a melt-blown layer, which comprises polyester fibres having an average diameter (d1) of less than 1.8 μm. The thickness of the nonwoven layer is less than 0.4 mm at a contact pressure of 0.1 bar. At least 25% of the polyester fibres of the melt-blown layer have a diameter (d) of less than 1 μm.

The present invention is generally related to a high capacity, high efficiency nonwoven filtration media comprising a gradient pore structure. In particular, the filtration media can comprise thermoplastic synthetic microfibers, fibrillated fibers, staple fibers, and a binder. Furthermore, the filtration media may be produced without the use of glass fibers or microglass fibers. Consequently, the filtration media of the present invention does not cause the same issues as conventional filtration media that comprises glass fibers and/or microglass fibers. Moreover, the filtration media can be used to treat fuel, lubrication fluids, hydraulic fluids, and various other industrial gases.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The additives are a mercapto-benzothiazole salts or mercapto-benzoxazole salts. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

A spunbond non-woven fabric includes a thermoplastic continuous filament. A CV value of air permeability of the non-woven fabric is 15% or less, bending resistance in a machine direction of the non-woven fabric is 40 mN or more and 80 mN or less, the non-woven fabric includes a projected part and a recessed part, 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 t.sub.D (t.sub.C<t.sub.D), and the 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)

0.65<t.sub.C/t.sub.D<1.0  (2).

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The additives are substituted benzothiazole compounds or substituted benzoxazole compounds. The substituent groups may be hydroxyl, mercapto, or aromatic groups. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

A coalescence separator for separating liquid droplets from a gas flow has a gas inlet and a gas outlet. A multi-layer structure of a plurality of individual layers of a coalescence filter medium is arranged between the gas inlet and the gas outlet, wherein the coalescence filter medium is provided with a glass fiber paper with glass fibers. The individual layers of the coalescence filter medium each have an individual layer thickness of more than 0.8 mm and maximally 5 mm, a grammage of greater than 80 g/m.sup.2 and less than 500 g/m.sup.2, and an air permeability of 350 l/m.sup.2s to 1,800 l/m.sup.2s. The multi-layer structure has between 2 and 80 of the individual layers.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The charge-enhancing additive is a substituted-benzimidazole compound. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The charge-enhancing additive is a dual-function charge-enhancing additive that enhances the charge of the electret and also has anti-microbial properties. The additives are substituted-benzimidazole or substituted-benzothiazole compounds. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.