Rhone-poulenc Chimie

Rhone-poulenc Specialites Chimiques

Rhone-poulenc Industries

Michel Letoffe

Pierre-Michel Peccoux

Patrice Perrin

Bernard Laisney

Jean-Marc Pujol

Roger Favre

Michel M Gay

Claude Millet

Georges Barrandon

Roger Cocco

Andre Gibard

Alain Gautier

Serge Serafini

Georges Favre

Georges Nielsen

Jean Ulrich

Andre Donnadieu

An accelerator system for the cold crosslinking of polymers which harden on exposure to moisture by hydrolysis/condensation, comprising: (C) x parts by weight of a catalyst for crosslinking the said polymers by polycondensation, x ranging from 0.01 to 10; (E) Y parts by weight of a solid inorganic compound containing an amount y of water in the form of water of hydration and/or water adsorbed by capillary condensation, this amount y ranging from 0.5 to 40 parts by weight, and which can represent up to 70% of the weight of the said solid inorganic compound; (F) z parts by weight of fillers, z ranging from 0 to 50; (D) 100-(x+Y+z) parts by weight of a diluent or of a solvent of the said catalyst (C), the diluent or solvent having a dynamic viscosity at 25.degree. C. of the order of 50 to 200,000 mPa.s; the respective amounts of the four constituents (C), (E), (F) and (D) being such that the system obtained exists in the form of a manipulable paste. The accelerator system is used for accelerating silicone compositions which harden on exposure to the moisture in air.

Accelerator system for crosslinking polymers which harden on exposure to

Functionalized diorganopolysiloxanes containing alkoxy endgroups, well adapted for the formulation of single-component cold-vulcanizable elastomer compositions therefrom, are prepared by reacting an .alpha., .omega.-dihydroxydiorganopolysiloxane oil with a polyalkoxysilane in the presence of a catalytically effective amount of lithium hydroxide.

LiOH catalyzed preparation of alkoxylated diorganopolysiloxanes

Organopolysiloxane compositions curable into elastomeric state, whether in single- or two-component form, comprise an .alpha.,.omega.-dihydroxypolydiorganopolysiloxane oil, a crosslinking agent therefor, optionally, inorganic fillers and an adhesion promoter, and a catalytically effective amount of a pentacoordinated tin monochelate produced by reacting a .beta.-dicarbonyl compound with an organotin salt.

Tin monochelate catalysis of organopolysiloxane compositions

The diorganopolysiloxane alpha, omega-diol oils are terminally alkoxylated by reacting same with a polyalkoxysilane in the presence of an organic oxime devoid of silicon atoms. The resulting functionalized oils are well adapted for the formulation of single-component, storage-stable organopolysiloxane CVE compositions.

Preparation of terminally alkoxylated diorganopolysiloxanes

Organopolysiloxanes curable into elastomeric state, well adapted as sealing materials for a variety of substrates and useful, e.g., in the automotive industry, are comprised of a polyhydroxylated polysiloxane, a polyacyloxysilane crosslinking agent, and an effective amount of at least one calcium oxide, strontium oxide and/or barium oxide cure accelerator therefor. The subject compositions are stable for at least 10 minutes at ambient temperature and crosslink on heating and/or addition of an aqueous or liquid carboxylic acid promoter thereto.

Organopolysiloxanes containing cure accelerators

Single-component diorganopolysiloxane compositions which are storage-stable in the absence of atmospheric moisture and which crosslink into silicone elastomeric state in the presence of moisture, are comprised of an alkoxy-terminated diorganopolysiloxane, a functionalization catalyst containing a primary or secondary amine group, a tin condensation catalyst, a filler material, and an effective stabilizing amount of an alkyl or aryl isocyanate-substituted diorganopolysiloxane.

Single-component, storage-stable diorganopolysiloxane CVE compositions

Single-component diorganopolysiloxane compositions which are storage-stable in the absence of atmospheric moisture and which crosslink into silicone elastomeric state in the presence of moisture, are comprised of an alkoxy-terminated diorganopolysiloxane, a functionalization catalyst containing a primary or secondary amine group, a tin condensation catalyst, a filler material, and an effective stabilizing amount of an isocyanurate of the formula: ##STR1## wherein W is --CH.sub.2).sub.n N.dbd.C.dbd.O and n ranges from 1 to 12.

Organopolysiloxane compositions comprising a polyhydroxylated polysiloxane and a polyacyloxysilane, whether in single- or two-component form, rapidly cure into elastomeric state (and are thus useful, e.g., as sealing materials) in the presence of a 2-carboxycarboxamide cure autoaccelerator.

Autoaccelerated organopolysiloxane elastomers

Storage stable, water-free, RTV organopolysiloxane adhesives curable in the presence of water or atmospheric moisture, and comprising a dihydroxydiorganopolysiloxane polymer, fillers, an amine fraction and a curing catalyst, are characterized by incorporation therein of a polyalkoxylated organosilane having the formula:

RTV storage stable, water-free organopolysiloxanes

Novel RTV organopolysiloxane compositions, advantageously two-component compositions, which are easily vulcanized into self-adhesive elastomers having excellent reversion properties, are comprised of (1) at least one alpha, omega-dihydroxydiorganopolysiloxane polymer having a viscosity of from about 500 to 1,000,000 mPa.s at 25.degree. C., the organic radicals of which being monovalent hydrocarbon radicals, (2) at least one filler material therefor, (3) at least one polyalkoxysilane or polyalkoxysiloxane cross-linking agent therefor, (4) a catalytically effective amount of at least one tin catalyst, and (5) at least one silane having the general formula: ##STR1## wherein R is an alkyl or alkoxy radical having from 1 to 4 carbon atoms, at least 2 of said radicals R being alkoxy radicals, R' is an alkyl radical having from 1 to 3 carbon atoms, and n is an integer of from 3 to 10.

RTV organopolysiloxane compositions and self-adhesive elastomers

Organopolysiloxane compositions readily cross-linked into elastomers, e.g., elastomeric seals, and advantageously formulated in either one- or two-component packages, are comprised of (A) a polyhydroxylated polysiloxane, (B) a polyacyloxysilane cross-linking agent and (C) a hardening accelerator therefor, said hardening accelerator being protectively microencapsulated within impermeable outer skin membranes adopted to be chemically or physically disrupted, e.g., by heat, irradiation or mechanical breaking, to permit the release of said accelerator (C) therefrom and consequent curing of the composition.

Curable organopolysiloxane compositions comprising microencapsulated

Organopolysiloxane compositions which rapidly harden to the elastomeric state, even at ambient temperatures, are comprised of (i) a polyhydroxylated polysiloxane, (ii) a polyacyloxysilane cross-linking agent therefor, and (iii) a hardening accelerator comprising an alkali or alkaline earth metal hydroxide. The subject compositions are useful, inter alia, for providing elastomeric seals.

Rapidly hardening organopolysiloxane compositions comprising

Provided are single component organopolysiloxane compositions which are hardenable at ambient temperatures and contain as the cross-linking agent silanes with hydrocarbonoyloxy (acyloxy) or ketoniminoxy groups. The compositions further comprise a cross-linking catalyst which is an organic derivative of titanium, e.g., a titanium ester, polytitanoxane, alkanolamine titanate, etc., or an organic derivative of zirconium, e.g., a zirconate, polyzirconate, etc. After cross-linking, the present compositions provide organopolysiloxane elastomers exhibiting good properties. The organopolysiloxane compositions are referred to as 'single component' to contrast them with the two-component organopolysiloxane compositions which are not storage stable and must therefore be handled in two separate packages, which problem is overcome by the present compositions.

Single component organopolysiloxane compositions containing silanes with

Organopolysiloxane compositions which rapidly harden to the elastomeric state, even at ambient temperatures, are comprised of (i) a polyhydroxylated polysiloxane, (ii) a polyacyloxysilane cross-linking agent therefor, and (iii) a hardening accelerator comprising water and an alkali or alkaline earth metal phosphate and/or polyphosphate. The subject compositions are useful, inter alia, for providing elastomeric seals.

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Sainte Foy Les Lyon, France

Michel Letoffe