Abstract: Silicon-tin compounds of the formulaR.sub.a Si(OSnR.sup.1 R.sup.2 OOCR.sup.3).sub.4-ain which R represents an alkyl or phenyl radical, R.sup.1, R.sup.2 and R.sup.3 are alkyl radicals and a is 0 or 1 and their use as condensation catalysts in the preparation of organopolysiloxane elastomers.

Abstract: Silicon-tin compounds of the formulaR.sub.a Si(OSnR.sup.1 R.sup.2 OOCR.sup.3).sub.4-ain which R represents an alkyl or phenyl radical, R.sup.1, R.sup.2 and R.sup.3 are alkyl radicals and a is 0 or 1 and their use as condensation catalysts in the preparation of organopolysiloxane elastomers.

Abstract: Silicon-tin compounds of the formulaR.sub.a Si(OSnR.sup.1 R.sup.2 OOCR.sup.3).sub.4-ain which R represents an alkyl or phenyl radical, R.sup.1, R.sup.2 and R.sup.3 are alkyl radicals and a is 0 or 1 and there use as condensation catalysts in the preparation of organopolysiloxane elastomers.

Abstract: Organopolysiloxane compositions which contain glass fibers having an average length of up to about 0.5 mm. The compositions are flowable in the absence of a solvent and can be cured at room temperature or moderately elevated temperatures to form elastomers having a high tear resistance and a high durometer.

Abstract: Organosilicon compounds having at least one hydrocarbon radical linked to at least 75 percent of the silicon atoms via an oxygen atom in which the hydrocarbon radical has at least one hydroxyl group and may be linked again to the same silicon atom or to another silicon atom via an oxygen atom are added to room temperature curable organopolysiloxane compositions to form compositions which are resistant to flow on vertical surfaces. When these compositions are exposed to atmospheric moisture at room temperature, they form elastomers having decreased Shore hardness and modulus on the surface in contact with the substrate as compared to the surface exposed to atmospheric moisture.

Abstract: The invention relates to a method for preparing a dental impression which comprises applying a dental impression material to a tooth of which an impression is to be taken, curing the material and thereafter removing the resulting impression from the tooth, said dental impression material being a mixture ofA. a diorganopolysiloxane containing terminal triorganosiloxy groups in which at least one vinyl group is present in each of the triorganosiloxy groups,B. an organopolysiloxane having at least three Si-bonded hydrogen atoms per molecule,C. a catalyst capable of promoting the addition of Si-bonded hydrogen to vinyl groups at room temperature and, if desired,D. additives such as fillers, pigments, flavoring substances and plasticizers.

Abstract: An improved process for preparing compositions capable of being converted into elastomers containing (A) triorganosiloxy-terminated diorganopolysiloxanes having at least one vinyl group in each terminal unit, (B) triorganosiloxy-terminated organopolysiloxanes containing organohydrogensiloxane units and diorganosiloxane units, (C) fillers which are hydrophobic or are capable of being rendered hydrophobic and having a surface area of at least 50 m.sup.2 /g and (D) catalysts which promote the addition of SiH groups to vinyl groups which comprises mixing organopolysiloxanes (B) containing organohydrogensiloxane (SiH) units with at least 75 percent by weight of the fillers (C) having a surface area of at least 50 m.sup.2 /g before mixing with the organopolysiloxanes (A) having triorganosiloxy-terminal units with at least one vinyl group in each terminal unit.

Abstract: The invention relates to paste-like mixtures that are used in the preparation of room temperature vulcanizable compositions comprising a cross-linking agent, a condensation catalyst and a hydrophobic silicon dioxide thickening agent which is solid at room temperature.

Abstract: The invention relates to a method for preparing dental impression materials which comprises mixingA. a diorganopolysiloxane containing terminal triorganosiloxy groups in which at least one of the triorganosiloxy groups contains a vinyl group withB. an organopolysiloxane having at least three Si-bonded hydrogen atoms per molecule,C. a catalyst capable of promoting the addition of Si-bonded hydrogen to vinyl groups at room temperature and, if desired,D. additives, such as fillers, pigments, flavoring substances and plasticizers.