Reference

Organopolysiloxane compositions containing polyacyloxysilanes and setting very rapidly to elastomers in the presence of a metal hydroxide-type accelerator

Organopolysiloxane compositions containing polyacyloxysilanes and setting very rapidly to elastomers in the presence of a metal hydroxide-type accelerator. Letoffe, Michel; Favre, Roger; Perrin, Patrice (Rhone-Poulenc Specialites Chimiques, Fr.). Fr. Demande FR 2540128 A1 3 Aug 1984, 26 pp. (French). (France). CODEN: FRXXBL. CLASS: IC: C08G077-38; C08K003-28; C09K003-10. APPLICATION: FR 83-1504 27 Jan 1983. DOCUMENT TYPE: Patent CA Section: 39 (Synthetic Elastomers and Natural Rubber) The title compns., useful as sealants, contain OH-contg. siloxanes, silanepolyol esters as vulcanizing agents, and alkali metal or alk. earth hydroxides as vulcanization accelerators. Thus, a dispersion of OH-terminated dimethylsiloxane (viscosity 4 Pa-s at 25°) 100, OH-terminated methylphenylsiloxane (viscosity 350 mPa-s) 1, MeSi(OAc)3 [4253-34-3] 6, pyrolytic SiO2 (sp. surface 20 m2/g) 20, quartz (av. particle size 5 m) 20, TiO2 (av. particle size 8 m) 20, and cyclohexane 72 parts was stable in the absence of moisture for 36 mo. A mixt. of this dispersion with 2.05% accelerator [dimethylsiloxane (viscosity 30 Pa-s) 69.8, pyrolytic SiO2 0.8, Ca(OH)2 28.8, and H2O 0.60 parts] required 19.5 min to reach a viscosity of 1.6 Pa-s at 25°, compared with 85 without added H2O.

Organopolysiloxane compositions containing polyacyloxysilanes and hardening very quickly into an elastomer in the presence of a phosphate-type accelerator

Organopolysiloxane compositions containing polyacyloxysilanes and hardening very quickly into an elastomer in the presence of a phosphate-type accelerator. Letoffe, Michel; Favre, Roger; Perrin, Patrice (Rhone-Poulenc Specialites Chimiques, Fr.). Fr. Demande FR 2540129 A1 3 Aug 1984, 26 pp. (French). (France). CODEN: FRXXBL. CLASS: IC: C08G077-38; C08K003-32; C09K003-10. APPLICATION: FR 83-1505 27 Jan 1983. DOCUMENT TYPE: Patent CA Section: 39 (Synthetic Elastomers and Natural Rubber) The title compns., useful as sealants, contain OH-contg. siloxanes, silanepolyol esters, and aq. alkali metal or alk. earth (poly)phosphates as vulcanization accelerators. Thus, mixing 100 parts mixt. of OH-terminated dimethylsiloxane (I) (viscosity 7 Pa-s at 25°) 100, I (viscosity 50 mPa-S) 4, MeSi(OAc)3 [4253-34-3] 5, (BuO)4Ti 0.004, pyrolytic silica (sp. surface 150 m2/g) 10, and diatomaceous silica (av. particle size 5 m) 85 parts with 5 parts mixt. of Na2HPO4.12H2O 20.4, dimethylsiloxane (viscosity 30 Pa-s) 100, and pyrolytic silica 2 parts gave a compn. which, when cured as a 4-mm layer at 22° and 65% relative humidity, had Shore A hardness 30, 35, 45, and 50 after 5, 10, 30, and 60 min, resp., compared with unmeasurable after 1 h in the absence of the phosphate.