Heraeus Quarzglas Gmbh & Co Kg

Juergen Roeper

Heinz Fabian

Udo Peper

Sven Schmidt

Andreas Helm

A known method for producing synthetic quartz glass comprises the method steps of: forming a stream of a SiOfeedstock material which contains octamethylcyclotetrasiloxane (D4) as the main component which has a reference molecular mass assigned to it, feeding the stream to a reaction zone in which the feedstock material is converted under formation of amorphous SiOparticles by pyrolysis or hydrolysis into SiO, depositing the amorphous SiOparticles on a deposition surface while forming a porous SiOsoot body, and vitrifying the SiOsoot body while forming the synthetic quartz glass. Starting therefrom, to enable the production of large-volume cylindrical soot bodies with outer diameters of more than 300 mm of improved material homogeneity, it is suggested according to the invention that the feedstock material contains additional components in the form of further polyalkylsiloxanes, wherein light polyalkylsiloxanes with a relative molecular mass of less than the reference molecular mass are contained with a weight fraction of at least 50 ppm, and heavy polyalkylsiloxanes with a relative molecular mass of more than the reference molecular mass are contained with a weight fraction of at least 30 ppm.

Method for producing synthetic quartz glass

The present invention relates to a method for producing synthetic quartz glass, comprising the steps of: providing a liquid SiOfeedstock material (), which comprises more than 70% by wt. of the octamethylcyclotetrasiloxane D4, vaporizing the SiOfeedstock material () into a gaseous SiOfeedstock vapor (), converting the SiOfeedstock vapor () into SiOparticles, depositing the SiOparticles on a deposition surface () while forming a SiOsoot body (), vitrifying the SiOsoot body () while forming the synthetic quartz glass. According to the invention it is provided that vaporizing the heated SiOfeedstock material () comprises an injection phase in an expansion chamber () in which the heated SiOfeedstock material () is atomized into droplets, the droplets having a mean diameter of less than 5 pm, preferably less than 2 &#x3bc;m.

Atomizing method for producing synthetic quartz glass

A method for producing synthetic quartz glass comprises providing a liquid SiOfeedstock material containing mainly octamethylcyclotetrasiloxane D4, vaporizing the SiOfeedstock material into a feedstock vapor, converting the feedstock vapor into SiOparticles, depositing the SiOparticles on a deposition surface while forming a porous SiOsoot body, and vitrifying the SiOsoot body while forming the synthetic quartz glass. To produce large-volume cylindrical soot bodies with outer diameters of more than 300 mm of improved material homogeneity, the liquid feedstock material contains additional components comprising hexamethylcyclotrisiloxane D3 and its linear homolog with a weight fraction mD3, dodecamethylcyclohexasiloxane D6 and its linear homolog with a weight fraction mD6, and tetradecamethylcycloheptasiloxane D7 and/or hexadecamethylcyclooctasiloxane D8 and its linear homologs with a weight fraction mD7+. The weight ratio mD3/mD6 is in a range between 0.5 and 500 and the weight fraction mD7+ is at least 20 wt. ppm.

Method for producing a semifinished product from synthetic quartz glass Methods for producing a semifinished product from synthetic quartz glass by plastic deformation of a softened SiOmass in a melt mold are known. Starting from this, to avoid fusion defects as much as possible and to obtain semifinished products of quartz glass in a reproducibly high quality, a method is suggested that comprises the following steps: (a) providing a porous SiOsoot body, (b) zonewise sintering of the SiOsoot body in the melt mold at a sintering temperature and during a sintering period with formation of a completely sintered transparent quartz glass body, and directly thereafter (c) shaping the sintered quartz glass body by softening in the melt mold with formation of a viscous quartz glass mass which fills the volume of the melt mold entirely or partly, and (d) cooling the quartz glass mass and removing the mass from the melt mold with formation of the semifinished product.

Growing community of inventors

Roitzsch, Germany

Juergen Roeper