Abstract: Nanoporous silicone resins and silicone resin films having low dielectric constants and a method for preparing such nanoporous silicone resins. The silicone resin comprises the reaction product of a mixture comprising (A) 15-70 mol % of a tetraalkoxysilane described by formula Si(OR1)4,  where each R1 is an independently selected alkyl group comprising 1 to about 6 carbon atoms, (B) 12 to 60 mol % of a hydrosilane described by formula HSiX3,  where each X is an independently selected hydrolyzable substituent, (C) 15 to 70 mole percent of an organotrialkoxysilane described by formula R2Si(OR3)3,  where R2 is a hydrocarbon group comprising about 8 to 24 carbon atoms or a substituted hydrocarbon group comprising a hydrocarbon chain having about 8 to 24 carbon atoms and each R3 is an independently selected alkyl group comprising 1 to about 6 carbon atoms; in the presence of (D) water, (E) hydrolysis catalyst, and (F) organic solvent for the reaction product.

Abstract: A water vapor-permeable waterproof fabric free from an environmental pollution problem upon being discarded is formed by coating a substrate fiber fabric with a composite coating layer including a lower layer (A) directly formed on the substrate fabric and an upper layer (B) formed on the lower layer (B), wherein the lower and upper layers are formed from one of polyetherester elastomers different from each other and each containing polyalkylene glycol (PAG) residues, and satisfy the following requirements: (a) in the polyetherester elastomer (PEEA), the polyalkylene glycol residues contain 90% by weight or more of polytetramethylene glycol residues; (b) in the polyetherester elastomer (PEEB), the polyalkylene glycol residues contain 50% by weight or more of polyethylene glycol residues; (c) the thickness of the composite coating layer is 5 to 50 &mgr;m; and (d) the lower layer (A) is in an amount of 5 to 40% by weight based on the total weight of the composite coating layer.