Silicone rubber sealant composition

A sealant composition for porous materials comprising:

• (a) a silanol-terminated polysiloxane having a molecular weight greater than about 2000;
• (b a multifunctional silane having functional groups which condense with silanol groups in the presence of atmospheric moisture at room temperature to form a cross-linked polymer;
• (c) a metal-containing catalyst in an amount sufficient to cause said condensation of said mixture in the presence of atmospheric moisture;
• (d) a nonaqueous volatile solvent which is nonreactive with the remaining components at a concentration of at least about 85 weight percent of the silane/polysiloxane/solvent mixture;
• and
• (e) a volatile or subliming chelating agent in an amount sufficient to prevent activity of said catalyst.

A sealant composition for porous materials comprising:

• (a) silanol-terminated polydimethylsiloxane;
• (b methyltriacetoxysilane in an amount sufficient to crosslink said silanol-terminated polydimethylsiloxane;
• (c) a metal-containing catalyst in an amount sufficient to cause said condensation of said mixture in the presence of atmospheric moisture;
• (d) a volatile or subliming chelating agent comprising 1,4-dioxane in an amount equimolar to the metal ions in said catalyst;
• and
• (e) a non aqueous volatile solvent selected from the group consisting of compositions which are non reactive with components (a) and (b) consisting of C.sub.1 -C.sub.5 alcohols, glycol ethers, stoddard solvent, aliphatic hydrocarbons at a concentration of at least about 85 weight percent of the silane/polysiloxane/solvent mixture.

A method for waterproofing a porous material comprising:

• (a) applying to said material at room temperature and in the presence of atmospheric moisture, a sealant composition comprising:
• (1) a silanol-terminated polysiloxane having a molecular weight greater than about 2000;
• (2) a multifunctional silane having functional groups which condense with silanol groups in the presence of atmospheric moisture at room temperature to form a cross-linked polymer;
• (3) a metal-containing catalyst in an amount sufficient to cause said condensation of said mixture in the presence of atmospheric moisture;
• (4) a non-aqueous volatile solvent which is non-reactive with the remaining components at a concentration of at least about 85 weight percent of the silane/polysiloxane/solvent mixture;
• (b) allowing said solvent to evaporate and said composition to cross-link such that a waterproof seal of said material is formed.

A method for temporarily preventing curing of the one-component room temperature vulcanizable silicone rubber sealant composition prior to application thereof to a substrate, and permitting curing of said composition following application to said substrate wherein said silicone rubber sealant composition comprises:

• (a) a silanol-terminated polysiloxane having a molecular weight greater than about 2000;
• (b) a multifunctional silane having functional groups which condense with silanol groups in the presence of atmospheric moisture at room temperature to form a cross-linked polymer;
• (c) a metal-containing catalyst in an amount sufficient to cause said condensation of said mixture in the presence of atmospheric moisture;
• p1 (d) a non-aqueous volatile solvent which is non-reactive with the remaining components at a concentration of at least about 85 weight percent of the silane/polysiloxane/ solvent mixture;
• said method comprising adding to said composition a volatile or subliming chelating agent in an amount sufficient to prevent activity of said catalyst, whereby curing of said composition occurs upon evaporation of said chelating agent and consequent release of said catalyst after application to said substrate.