The invention relates to a method for manufacturing water treated man-made vitreous fibres (MMVF) comprising:

a. providing a mineral melt,

b. providing a fiberizing apparatus,

c. fiberizing the mineral melt to form man-made vitreous fibres (MMVF),

d. collecting the MMVF, and thereafter

e. applying about 0.1 wt % to about 1 wt % water, based on the weight of the MMVF, to the MMVF to form water treated MMVF.

The invention relates to a method for manufacturing water treated man-made vitreous fibres (MMVF) comprising:

a. providing a mineral melt,

b. providing a fiberizing apparatus,

c. fiberizing the mineral melt to form man-made vitreous fibres (MMVF),

d. collecting the MMVF, and thereafter

e. applying about 0.1 wt % to about 1 wt % water, based on the weight of the MMVF, to the MMVF to form water treated MMVF.

Processes for increasing an affinity of a filter media to airborne viral particles. A fiber substrate comprising borosilicate is provided. The fiber substrate may comprise acidic functional groups. A metal salt solution is introduced to the fiber substrate to form a treated substrate. The metal salt solution includes divalent and/or trivalent metal cations. The pH of the metal salt solution is adjusted, and a divalent and/or trivalent metal cation is exchanged with a proton from the acidic functional groups. The metal may be present in an amount ranging from about 0.001 to about 3.0 wt. % of the treated fiber substrate. The treated fiber substrate is incorporated into a filter media before or after the deposition of the metal onto the fiber substrate.

Processes for increasing an affinity of a filter media to airborne viral particles. A fiber substrate comprising borosilicate is provided. The fiber substrate may comprise acidic functional groups. A metal salt solution is introduced to the fiber substrate to form a treated substrate. The metal salt solution includes divalent and/or trivalent metal cations. The pH of the metal salt solution is adjusted, and a divalent and/or trivalent metal cation is exchanged with a proton from the acidic functional groups. The metal may be present in an amount ranging from about 0.001 to about 3.0 wt. % of the treated fiber substrate. The treated fiber substrate is incorporated into a filter media before or after the deposition of the metal onto the fiber substrate.

A soundproofing material including a porous body having a cell structure and including inorganic fibers other than asbestos, wherein an average cell diameter is more than 300 μm and 1000 μm or less, a bulk density is 0.007 to 0.024 g/cm.sup.3, and a flow resistivity is 170,000 to 2,000,000 Ns/m.sup.4.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.

An optical fiber having an axial direction and a cross section perpendicular to the axial direction, and a method and preform for producing such an optical fiber. The optical fiber is adapted to guide light at a wavelength λ, and includes a core region, an inner cladding region surrounding said core region, and at least one of a first type of feature including a void and a surrounding first silica material. The core, the inner cladding region and the first type of feature extends along said axial direction over at least a part of the length of the optical fiber. The first silica material has a first chlorine concentration of about 300 ppm or less.