Sealant with siloxaphobic surface, composition and method of preparation

摘要

A sealant made from a room temperature curing polydimethylsiloxane composition that has a siloxaphobic surface layer at the air-sealant interface where this layer is a fluorocarbon compound and a drying oil oxidation product. Elastomeric compositions made from polydimethylsiloxanes having both low reactivity endgroups and high reactivity endgroups and a siloxaphobic agent of fluorocarbon alcohol or a reaction product of the fluorocarbon alcohol and a hydrolyzable silane, are particularly useful for sealing buildings because they can withstand expansions and contractions. One siloxaphobic agent is the reaction product between a fluorocarbon alcohol and a methyltri(methylethylketoximo)silane and the formula of one of the reaction product compounds is wherein x has an average value of at least 6.y