Abstract: Compositions which are stable in the absence of oxygen are formed by mixing the following substantially in the absence of oxygen(A) 100 parts by weight of a mercapto-functional organosiloxane containing an average of at least two mercapto-functional substituents per molecule;(B) 0 to 200 parts by weight of at least one filler;(C) a catalytic amount, preferably from 0.1 to 6 parts by weight, of an iron carbonyl catalyst selected from the group consisting of Fe(C0).sub.5, Fe.sub.2 (CO).sub.9, Fe.sub.3 (CO).sub.12, dicyclopentadienyldiiron tetracarbonyl, butadieneiron tricarbonyl and cyclohexadieneiron tricarbonyl; and(D) 0.1 to 6 parts by weight of an acid which meets a particular set of criteria.The compositions polymerize or cure to form higher molecular weight products at room temperature upon exposure to oxygen. These compositions are especially useful as coatings because they possess a rapid rate of surface cure at room temperature.

Abstract: Compositions which are stable in the absence of oxygen are formed by mixing the following substantially in the absence of oxygen:(A) 100 parts by weight of at least one mercapto-functional organosilicon-organic copolymer or mixtures of at least two different types of components selected from the following three types: the above copolymers, mercapto-functional organic compounds free of silicon atoms and mercapto-functional organosilicon compounds wherein all three types contain an average of at least two mercapto groups per molecule;(B) 0-200 parts by weight of at least one filler;(C) a catalytic amount, preferably from 0.1 to 6 parts by weight, of an iron carbonyl catalyst selected from the group consisting of Fe(CO).sub.5, Fe.sub.2 (CO).sub.9, Fe.sub.3 (CO).sub.12, dicyclopentadienyldiiron tetracarbonyl, butadieneiron tricarbonyl and cyclohexadieneiron tricarbonyl; and(D) 0.1-6 parts by weight of an acid, such as 2-ethylhexanoic acid, which meets a particular set of criteria.

Abstract: Compositions which are stable in the absence of oxygen are formed by mixing the following substantially in the absence of oxygen(A) 100 parts by weight of at least one mercapto-functional organic compound which contains an average of at least two mercapto groups per molecule;(B) 0 to 200 parts by weight of at least one filler;(C) a catalytic amount, preferably from 0.1 to 6 parts by weight, of an iron carbonyl compound selected from the group consisting of Fe(CO).sub.5, Fe.sub.2 (CO).sub.9, Fe.sub.3 (CO).sub.12, dicyclopentadienyldiiron tetracarbonyl, butadieneiron tricarbonyl and cyclohexadieneiron tricarbonyl; and(D) 0.1 to 6 parts by weight of an acid, such as 2-ethylhexanoic acid, which meets a particular set of criteria.The compositions polymerize or cure to form higher molecular weight products at room temperature upon exposure to oxygen. These compositions are especially useful as coatings because they possess a rapid rate of surface cure.

Abstract: Compositions stable in the absence of oxygen are formed by mixing the following substantially in the absence of oxygen(A) mercapto-functional organosiloxanes containing an average of at least two mercapto-functional substituents per molecule;(B) optionally, at least one filler;(C) a catalytic amount of a metal carbonyl compound selected from the group consisting of Fe(CO).sub.5, Fe.sub.2 (CO).sub.9, Fe.sub.3 (CO).sub.12, dicyclopentadienyldiiron tetracarbonyl, butadieneiron tricarbonyl, cyclohexadieneiron tricarbonyl, Ni(CO).sub.4, dicyclopentadienyldinickel dicarbonyl, Mn.sub.2 (CO).sub.10, methylcyclopentadienylmanganese tricarbonyl and cyclopentadienylcobalt dicarbonyl, preferably from 0.1 to 6 parts by weight of iron carbonyl catalyst per 100 parts by weight of part (A).The compositions polymerize or cure upon exposure to oxygen.

Abstract: Compositions stable in the absence of oxygen are formed by mixing the following substantially in the absence of oxygen(A) mercapto-functional organosiloxanes containing at least two mercapto groups per molecule,(B) optionally, a filler, and(C) a catalytic amount of a cobaltocene of the formula (R.sup.3 C.sub.5 H.sub.4)Co(C.sub.5 H.sub.4 R.sup.4), wherein each R.sup.3 and R.sup.4 is hydrogen or methyl, preferably, 0.01-6 parts by weight of (C.sub.5 H.sub.5).sub.2 Co per 100 parts by weight of (A) above.The compositions polymerize or cure upon exposure to oxygen. By utilizing various types and amounts of mercapto-functional organosiloxanes, higher molecular weight products useful as encapsulating gels, coating resins, or elastomeric sealants can be obtained by the method of exposing the compositions of the present invention to oxygen.