Schott Glaswerke

Schott Glas

Hartmut Paschke

Johann Daimer

Hermann Ditz

Susanne Kessler

Hans-Werner Beudt

Friedrich Siebers

Christian Kunert

Dietrich Mund

Danuta Grabowski

Marc Clement

Hrabanus Hack

Ludwig Gaschler

Richard Haring

Susanne Kiermayer

Ute Wolfel

Alwin Weitzel

Gerd Kreutzmann

The invention relates to a glass powder, where at least one oxidizing agent or one reducing agent is added to the glass powder. The glass powder is preferably used as dental glass powder.

Glass powder and use thereof

The invention relates to a barium-free, X-ray-opaque dental glass, to a dental glass/polymer composite comprising the glass, and to the use thereof as dental filling, where the dental glass has the following composition (in % by weight): SiO,20-45, Al,O,5-35, B,O,1-10, Na,O 1-10, K,O 0-8, Cs,O 0-8, sum all alkali metal oxides 1-15, CaO 0-8, SrO 0-27, ZnO 2-20, ZrO,2-10, P,O,0-10, La,O,0-10, F 2-20, the total content of B,O,, ZnO, ZrO,and La,O,is >20% by weight, and the refractive index n,of the dental glass is in the range from 1.47 to 1.70.

Barium-free, X-ray-opaque dental glass and dental glass/polymer composite, and the use thereof

An improved filling material for a composite solder glass based on doped PbTiO,is disclosed, in which up to 35 atom % of the Pb atoms and up to 35% Ti atoms are replaced by Mg and/or Ca and a portion of O atoms in the doped PbTiO,is replaced with halogen atoms, preferably fluorine atoms. This filling material and composite solder glasses containing it are useful for hermetic sealing, soldering and/or coating of individual components made of glass material, glass-ceramic material, ceramic material and metal in the manufacturing of components and devices for electrical engineering and electronics, for hermetic encapsulation of electronic components, vacuum-tight seals or closures of display tubes or for display devices. They are also useful for coating and bonding of special glasses. The filling material can be made by reaction sintering of a powder mixture at temperatures of 800&deg; C. to 1250&deg; C.

Composite solder glass, filling material for same and methods of using same

Disclosed is a barium-free glass of good x-ray absorption, which has a composition (in wt.-% on the oxide basis) of SiO.sub.2 50-75; ZrO.sub.2 5-30; Li.sub.2 O 0-5; Na.sub.2 O 0-25; K.sub.2 O 0-25; .SIGMA. alkali oxides 0-25. Preferred is a dental glass of the composition of SiO.sub.2 55-70; ZrO.sub.2 10-25; Li.sub.2 O 0-15; Na.sub.2 O 10-25; K.sub.2 O 0-15; .SIGMA. alkaloids 15-25. The glass can furthermore contain also up to 3 wt.-% of fluorine, up to 5 wt.-% of MgO, up to 5 wt.-% of TiO.sub.2, and in each case up to 10 wt.-% of the oxides Al.sub.2 O.sub.3, GeO.sub.2, P.sub.2 O.sub.5, La.sub.2 O.sub.3, Y.sub.2 O.sub.3, Ta.sub.2 O.sub.3, Gd.sub.2 O.sub.3, ZnO and Nb.sub.2 O.sub.5. The glass finds its use in powder form with an average particle size of .ltoreq.10 .mu.m as filler for dental composites for filling teeth.

Barium-free dental glass having good x-ray absorption

For the preparation of high purity glass powder having a mean particle size of .ltoreq.10 .mu.m, glass powder having a larger particle size up to 300 .mu.m is ground to the desired particle size in a stirred mill with glass grinding elements in the presence of a grinding liquid comprising water or preferably a mixture of at least 50% by weight of water and at least one water-soluble, oxygen-containing organic compound having 1 to 5 carbon atoms in the molecule, e.g., tert.-butyl alcohol; the ground slurry is then frozen, and the solvent is subsequently removed from the frozen slurry by freeze-drying. A resultant glass powder with a mean particle size d.sub.50 of 0.5 to 2 .mu.m is particularly suitable as a filler for synthetic resins in the dental sector.

Preparation of very fine glass powder of high purity

For the production of a composite glass powder of any particle size from a fine particle size, multi-component mixture of a low-melting glass powder, fillers, and additives, the fine particle size, multicomponent mixture is sintered for 10-60 minutes at a temperature at which the base glass has a viscosity of 10.sup.5 to 10.sup.6.5 dPas, and the resultant sintered cake is ground to a powder of the desired particle size. If the multicomponent mixture comprises components decomposable with the release of gas, e.g., copper carbonate, the latter are decomposed prior to sintering at a temperature below the sintering temperature. The resultant composite glass powder containing copper oxide can be used for coating varistors.

Production of composite glass powder of any desired particle size from a

A glass sealant comprises a mixture of about 70-90% of a solder glass powder of a low-melting lead-borate glass with a transformation temperature of 330.degree. C. or lower, 1-20% by weight of cordierite powder, and 1-25% by weight of mullite powder, with the combined content of cordierite and mullite powder being from about 10-30%. The lead-borate glass comprises from about 82-88% by weight of PbO, 12-17% by weight of B.sub.2 O.sub.3, 0-1% by weight of SiO.sub.2, and 0-1% by weight of Al.sub.2 O.sub.3. Both the cordierite and mullite powder are preferably synthetically produced to reduce the .alpha.-radiation. The synthetically produced cordierite powder preferably still contains up to about 9% by weight of a non-crystalline vitreous phase. The grain size of the powders is preferably under 100 microns. This glass sealant has well-balanced properties relative to thermal expansion, melting temperature, dielectric constant, loss angle, mechanical strength, thermal shock resistance, and chemical resistance. It is particularly suitable as ceramic dual-line package solder (CERDIP) for sealing of aluminum oxide housings for integrated circuits.

Glass sealant containing lead borate glass and fillers of mullite and

A biocompatible glass which can be melted using infra-red radiation contains, based on oxide, 65-68% by weight of SiO.sub.2, 0-3% by weight of Li.sub.2 O, 12-14% by weight of Na.sub.2 O, 2.5-4% by weight of K.sub.2 O, 15-17% by weight of .SIGMA. alkali metal oxides, 2-3% by weight of MgO, 4.2-5.5% by weight of CaO, 0-2% by weight of BaO, 3-4 % by weight of Al.sub.2 O.sub.3, 0-1.0 by weight of B.sub.2 O.sub.3 and 2.7-4.1% of FeO. The glass, due to its infra-red meltability and its physiological accertability, is suitable for the encapsulation of sensitive materials, such as transponders or minitransmitters, which are implanted in a living body, or as ampoule glass for melt-encapsulation of sensitive substances.

Biocompatible infused absorption glass containing FeO

Lead-zinc-borosilicate glass is provided having a boundary wetting angle with respect to ZnO of at most 40.degree., a processing temperature of at most 540.degree. C., a composition, consisting essentially of, in percent by weight on oxide basis, of

Lead-zinc-borosilicate glass

To lead an optical waveguide through a housing wall, the optical waveguide is, in one section freed of its protective layer and hermetically connected in a bushing by glass soldering it to the bushing. In at least one load-relieving section leading out of the bushing, the optical waveguide is fastened by its protective layer to an extension of the bushing. The bushing is hermetically set into the housing wall.

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Ergolding, Germany

Hartmut Paschke