Abstract: Resin compositions containing (a) unsaturated polyester, (b) polymerizable monomer, (c) thermoplastic resin, (d) a polymerization initiator, and (e) hollow glass microspheres with a true density of 0.5 to 1.3 g/cm.sup.3 and an elution alkalinity of 0.05 meq/g or less; molding materials obtained by impregnating glass fibers with such resin compositions; and molded products obtained by curing such molding materials.The molding materials have a superior workability and are useful for the production of parts to be coated, such as automotive external body panels. The molded products are light in weight and are highly resistant to water. Defective adhesion of coating or blisters does not occur.

Abstract: Quickly curable unsaturated polyester composition with improved surface characteristics and stability in storage contains 20-40 weight parts of unsaturated polyester, 20-60 weight parts of vinyl monomer, 0.01-1.0 weight parts of BHT (ditertiary butyl hydroxy toluene), and 10-40 weight parts of thermoplastic resin such that the total is 100 weight parts. In addition, 0.001-0.1 weight parts of compound with effect of inhibiting polymerization at temperatures over 100.degree. C. are contained against the total of 100 weight parts. Molding materials are obtained by impregnating glass fibers with such compositions and products are obtained by curing such molding materials.

Abstract: A curable unsaturated polyester resin composition contains graft copolymers each having 10-60 weight % of a first constituent given by ##STR1## 38-89.7 weight % of a second constituent given by ##STR2## and 0.3-2 weight % of a third constituent which is a vinyl monomer unit having carboxylic acid or carboxylic anhydride groups, unsaturated polyester, vinyl monomer, a filler, a curing catalyst, and reinforcing fibers, where either of R.sup.1 and R.sup.2 is H, the other being either H or CH.sub.3, R.sub.3 is ethylene group or propylene group, R.sup.4 is hydrocarbon group with 1-18 carbton atoms, R.sup.5 is alkyl group with 1-4 carbon atoms, R.sup.6 is alkyl group with 1-3 carbon atoms, m is 6-90 and n is 1-5.