A process for the manufacture of an insulating product based on mineral fibres bonded by an organic binder, includes applying a sizing composition to the mineral fibres, forming an assembly of the mineral fibres, heating the assembly of mineral fibres until the sizing composition has cured, wherein the sizing composition includes the following constituents within the limits defined below, expressed as fractions by weight with respect to the total weight of the composition: from 80% to 98% of water, from 2% to 20% of water-soluble poly(furfuryl alcohol) and less than 0.5% of furfuryl alcohol, and the mineral fibres are fibres of aluminosilicate glass including aluminum oxide, Al.sub.2O.sub.3, in a fraction by weight of between 14% and 28%.

Disclosed herein are glass compositions, articles made from the disclosed glass compositions, and methods of making the same. More specifically, disclosed herein is a glass composition comprising from about 10 to about 14 mol % of K.sub.2O; from 0 to about 4 mol % of CaO; from about 14 to about 18 mol % of Al.sub.2O.sub.3; and from about 66 to about 74 mol % SiO.sub.2.

The invention provides methods of making man-made vitreous fibres (MMVF), comprising providing an electric furnace having molybdenum electrodes, providing mineral raw material, wherein the mineral raw material comprises (a) particulate material that comprises metallic aluminium and (b) other mineral component, introducing the mineral raw material into the furnace, melting the mineral raw material to form a mineral melt, and forming MMVF from the mineral melt, with the benefit of reduced shrinkage of consolidated MMVF products.

The invention provides methods of making man-made vitreous fibres (MMVF), comprising incorporating metallic aluminium into the mineral charge, with the benefit of reduced shrinkage of consolidated MMVF products.

A method for manufacturing of an optical fibre preform (100) using optimized core particles includes optimization of particles of calcium aluminum silicate powder (104), utilizing the optimized core particles, sintering the optimized core particles inside a fluorine doped glass tube (106) and drawing of an optical fibre. Particularly, the optimization of the particles of calcium aluminum silicate powder (104) facilitates formation of the optimized core particles and the optimized core particles are filled inside the fluorine doped glass tube (106). Moreover, sintering of the optimized core particles solidifies and adheres smoothly with the fluorine doped glass tube (106) for manufacturing of the optical fibre preform (100).

A method for drawing an optical fibre from an optical fibre preform with a core section, a cladding section, a first gap and a second gap. The optical fibre preform is attached to an optical fibre draw tower through a handle. In addition, the optical fibre preform is connected to a vacuum system to supply and remove gas from the first gap and the second gap. Moreover, the gas is supplied to create a thermal barrier between the core section and the cladding section during heating of the optical fibre preform. Further, the optical fibre preform is heated inside a heating furnace to draw the optical fibre from the optical fibre preform.

An optical fibre including a core region defined along a central longitudinal axis of the optical fibre and a cladding region concentrically surrounds the core region of the optical fibre. In particular, the core region has a first radius r.sub.1 and a first refractive index n.sub.1. Moreover, the cladding has a second radius r.sub.2 and a second refractive index n.sub.2. Furthermore, the optical fibre has a step index profile.

The present disclosure provides a novel glass composition that has a low permittivity and is suitable for mass production. A glass composition provided satisfies, in wt %, for example, 40≤SiO.sub.2≤60, 25≤B.sub.2O.sub.3≤45, 0≤Al.sub.2O.sub.3≤18, 0<R.sub.2O≤5, and 0≤RO≤12, and satisfies at least one of: i) SiO.sub.2+B.sub.2O.sub.3≥80 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9; and ii) SiO.sub.2+B.sub.2O.sub.3≥78, SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9, and 0<RO<10. Another glass composition provided includes SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, R.sub.2O, and 3<RO<8 at the same contents as the above, and satisfies SiO.sub.2+B.sub.2O.sub.3≥75 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3<97, where R.sub.2O═Li.sub.2O+Na.sub.2O+K.sub.2O and RO═MgO+CaO+SrO.

A resin composition comprises a base resin containing an urethane (meth)acrylate oligomer, a monomer having a phenoxy group, and a photopolymerization initiator, and hydrophobic inorganic oxide particles, wherein the viscosity is 300 mPa.Math.s or more and 4200 mPa.Math.s or less at 45° C. and the content of the monomer having a phenoxy group is 1% by mass or more and 30% by mass or less based on the total amount of the base resin.

The invention provides a method to form a melt for making man-made vitreous fibres, in which mineral raw material is melted in a gas-fired cyclone furnace and the mineral charge comprises a material that comprises metallic aluminium.