ROOM TEMPERATURE CURING POLYORGANOSILOXANE COMPOSITION

摘要

PROBLEM TO BE SOLVED: To improve fire retardance, curing properties and storage stability by using a composition containing a polyorganosiloxane composition, a curing catalyst and a zinc carbonate of which purity and thermogravimetric loss by thermal analysis are specific values or more. SOLUTION: This polyorganosilane composition (A) contains a silicon functional polydiorganosiloxane having an average of over 2 hydrolyzable groups as silicon functional groups in a molecule and/or a silicon functional polydiorganosiloxane having an average of 2 or more silicon functional groups in a molecule and a cross-linking agent. A zinc carbonate has a purity of 95% or more and a thermogravimetric loss of 33% or more. The zinc carbonate generates a significant amount of carbon dioxide effective in fire retardance. Preferably, the amount of carbon dioxide generated in thermal decomposition is 30% or more. A room temperature curing polyorganosiloxane composition preferably contains 0.05-10 pts.wt. of the curing catalyst and 5-50 pts.wt. of the zinc carbonate based on 100 pts.wt. of component (A).