Abstract: Organopolysiloxane compositions are prepared with high throughput and less process time, by a process in which organopolysiloxanes, processing aids and fillers are mixed and kneaded in the presence of water to give raw mixtures and the raw mixtures are subsequently devolatilized and freed of water in a heating and devolatilizing step at temperatures in the range from 100° C. to 250° C.

Abstract: Organopolysiloxane compositions are prepared with high throughput and less process time, by a process in which organopolysiloxanes, processing aids and fillers are mixed and kneaded in the presence of water to give raw mixtures and the raw mixtures are subsequently devolatilized and freed of water in a heating and devolatilizing step at temperatures in the range from 100° C. to 250° C.

Abstract: Organopolysiloxane compositions having a 25° C. viscosity of at least 500 Pa·s., are continuously prepared by mixing and kneading organopolysiloxanes and fillers in a first process stage, in a kneading cascade having at least two kneading chambers arranged in series each containing two kneading tools on parallel axes, capable of being driven in corotating or counterrotating directions, the chambers connected to one another by means of openings through which material can pass in a direction transverse to the axes of the kneading tools, the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, to give raw mixtures and kneading and degassing the raw mixtures, in a second process stage at from 100° C. to 250° C. in a continuously operated double trough kneader having a discharge screw.

Abstract: Organopolysiloxane compositions having a 25° C. viscosity of at least 500 Pa·s., are continuously prepared by mixing and kneading organopolysiloxanes and fillers in a first process stage, in a kneading cascade having at least two kneading chambers arranged in series each containing two kneading tools on parallel axes, capable of being driven in corotating or counterrotating directions, the chambers connected to one another by means of openings through which material can pass in a direction transverse to the axes of the kneading tools, the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, to give raw mixtures and kneading and degassing the raw mixtures, in a second process stage at from 100° C. to 250° C. in a continuously operated double trough kneader having a discharge screw.

Abstract: Silicone rubber compositions useful for high-voltage insulators, and which cure to give silicone rubbers having a low combustibility, are addition-crosslinkable or peroxide-crosslinkable silicone rubber compositions containing aluminum hydroxide as filler, with the uncrosslinked composition having a storage stability which is improved compared to the prior art and improved processing properties by including an acid, base, or a compound which liberates an acid or base upon heating. These improved properties are achieved both with surface-treated aluminum hydroxide and with untreated aluminum hydroxide.

Abstract: Silicone rubber compositions useful for high-voltage insulators, and which cure to give silicone rubbers having a low combustibility, are addition-crosslinkable or peroxide-crosslinkable silicone rubber compositions containing aluminum hydroxide as filler, with the uncrosslinked composition having a storage stability which is improved compared to the prior art and improved processing properties by including an acid, base, or a compound which liberates an acid or base upon heating. These improved properties are achieved both with surface-treated aluminum hydroxide and with untreated aluminum hydroxide.

Abstract: Compositions prepared by mixing (A) 50-90 wt % of organopolysiloxane having a viscosity of from 50 to 100·106 mm2/s at 25° C., (B) 10-50 wt % of a metal oxide from the group consisting of titanium oxide, zirconium dioxide, zinc oxide, cerium(III) and cerium(IV) oxide, (C) 0.3-5 wt % of organosilicon compound containing basic nitrogen bound to silicon via carbon, (D) 0.05-0.5 wt % of platinum calculated as the element, in the form of a bis(alkynyl)platinum complex which additionally includes donor ligands, and (E) from 0 to 5 wt %, preferably 0 wt %, of further components, the sum of the percentages chosen within each of the ranges specified under (A) to (E) being 100 wt %, and the wt % in each case being based on the total weight of the additive, are highly suitable as additives to crosslinkable organosilicon compositions, providing one or more of improved tracking resistance, high arc resistance, and decreased flammability.

Abstract: Compositions prepared by mixing

Abstract: Curable organopolysiloxane compositions comprising a platinum catalyst selected from the group consisting of (PR23)2Pt(—C≡C—R3)2  (III), (R22P—R4—PR22)Pt(—C≡C—R3)2  (IV) and H—C≡C—R5—C≡C—[—Pt(PR23)2—C≡C—R5—C≡C—]e—H  (V) where R2, R3, R4, R5 and e are as defined in claim 1.

Abstract: Crude 2-mercaptobenzothiazole is purified by a process in which the crude 2-mercaptobenzothiazole is dissolved in relatively high-boiling aliphatic or cycloaliphatic alcohols or in mixtures of the alcohols mentioned or azeotropes thereof with water at temperatures of 60.degree. to 200.degree. C., optionally under elevated pressure, or is suspended in relatively high-boiling aliphatic or cycloaliphatic alcohols, aliphatic or cycloaliphatic ethers, organic acids or esters thereof at temperatures of 10.degree. to 100.degree. C., the solution or suspension is subsequently cooled and the product precipitating is filtered off and optionally washed.