A highly temperature-resistant glass fiber and a preparation method therefor. The glass fiber comprises 62-66 wt % of SiO.sub.2, 14-19 wt % of Al.sub.2O.sub.3, 15-20 wt % of CaO, 0-2 wt % of MgO, 0-3 wt % of Fe.sub.2O.sub.3, and 0-1.2 wt % of TiO.sub.2, the total content of Na.sub.2O and K.sub.2O is 0.1-0.8 wt %. By precisely controlling the mixture of the components, the glass fiber has good resistance to high temperature and formability, and significantly increases the high-temperature softening point. The glass fiber has a forming temperature of not exceeding 1380° C., an upper limit temperature of devitrification of lower than 1280° C., and a high temperature softening temperature of 950° C. or above.

The manufacture of fiberglass filtration media, and particularly paint arrestance fiberglass media, is disclosed. Fiberglass filtration media is formed in part by controlling the speed of a melter traversing a drum. The fiberglass media passes through rollers and water sprays before it enters a curing apparatus. Progressive density changes from the air intake side to the air exit side of the media result in increased filtration qualities.

A highly temperature-resistant glass fiber and a preparation method therefor. The glass fiber comprises 62-66 wt % of SiO.sub.2, 14-19 wt % of Al.sub.2O.sub.3, 15-20 wt % of CaO, 0-2 wt % of MgO, 0-3 wt % of Fe.sub.2O.sub.3, and 0-1.2 wt % of TiO.sub.2, the total content of Na.sub.2O and K.sub.2O is 0.1-0.8 wt %. By precisely controlling the mixture of the components, the glass fiber has good resistance to high temperature and formability, and significantly increases the high-temperature softening point. The glass fiber has a forming temperature of not exceeding 1380 C., an upper limit temperature of devitrification of lower than 1280 C., and a high temperature softening temperature of 950 C. or above.

The manufacture of fiberglass filtration media, and particularly paint arrestance fiberglass media, is disclosed. Fiberglass filtration media is formed in part by controlling the speed of a melter traversing a drum. The fiberglass media passes through rollers and water sprays before it enters a curing apparatus. Progressive density changes from the air intake side to the air exit side of the media result in increased filtration qualities.

A fibrous insulation product with improved thermal resistance and method of making it are provided. A plurality of base fibers (e.g. glass) are formed into an insulation product, which may be bindered or unbonded. At least one infrared opacifying agent, such as soot, carbon black or graphite, is applied to the fibrous insulation product such that the base fibers are substantially uniformly coated with opacifying agent. The opacifying agent may be applied, for example, from a fluid suspension or by pulling the fiber through a sooty flame. When opacifying agent applied via a suspension and a binder is desired, it is preferable to avoid binder dispersions that can dislocate the opacifying agent. Alternative binder applications may include co-mingling of base fibers with binder fibers, or other physical or mechanical distributions.