SEDL / STP / STP1069-EB / STP26810S

Silicon Modified Polyethers for Moisture Cured Sealants

Timberlake, JF
Research Scientist, Union Carbide Chemicals and Plastics Company Inc., Technical Center, South Charleston, WV

Pages: 11    Published: Jan 1990

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Abstract

Silicon modified polyethers are an intermediate for the preparation of one-part and two-part sealants. Silicon modified polyethers consist of a polyoxypropyl-ene backbone with methyldimethoxysilane end groups. Curing with moisture in the presence of catalysts gives flexible polymers with siloxane bonds connecting the poly-ethers. The primary application for these silicon modified polyethers is in construction sealants.

Silicon modified polyethers give soft sealants which have excellent weatherability and durability (joint movement) with little changes in properties after four years under normal use conditions. Weathering data demonstrate that these sealants will last for many years in outdoor exposure. The sealants show good adhesion to most substrates including aluminum, mortar, and stone. Good curing rates are observed in both one-part and two-part sealants over a range of temperatures. The sealants are nonstaining on stone and can be easily painted.