There is provided herein a composition comprising (a) a mercapto-functional silicon compound having the general Formula (I):

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and a reactive resin containing at least one epoxy and/or (meth)acrylate group. There is also provided a silylated resin resulting from the reaction product of mercapto-functional silicon compound (a) and reactive resin contain at least one epoxy and/or (meth)acrylate groups.

A molding composition formulation includes a thermoset cross-linkable 12 to 45 micron polymeric resin. Hollow glass microspheroids are present from 2 to 12 total weight percent. An article formed from such a composition is further strengthened by the addition of a surface activating agent bonded to the surface of the glass microspheroids. Conventional particulate fillers when added to an inventive formulation provide enhanced performance when the filler particle has a size sufficiently small to insert within adjacent microspheroid interstitial voids. An unsaturated polyester resin so formed is particularly well suited for the formation of sheet molding compound formulations.

One of the purposes of the present invention is to provide an epoxy resin composition having excellent storage stability and curability while being curable at a low temperature in a short period of time. The present invention provides an epoxy resin composition comprising: (A) a non-silicone-modified epoxy resin having two or more epoxy groups per molecule; (B) an aromatic amine-based curing agent having two or more amino groups per molecule, in an effective amount for curing the epoxy resin; (C) a silicone-modified epoxy resin, in an amount of 1 to 200 parts by mass, relative to 100 parts by mass of component (A); (D) an aluminum chelate compound, in an amount of 0.05 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the total of components (A), (B), and (C); (E) at least one selected from an alkoxysilane having one or more phenyl groups per molecule and one or more alkoxy groups per molecule, and a partially hydrolyzed condensate of the alkoxysilane, in an amount of 0.5 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the total of components (A), (B), and (C); and (F) an inorganic filler, in an amount of 10 parts by mass or more and 1,000 parts by mass or less, relative to 100 parts by mass of the total of components (A), (B), and (C).