| abstract |
A resin mortar composition or resin concrete composition comprising (a) a low shrinking resin, which consists of a block copolymer mixture, (b) an unsaturated polymer and (c) a monomer copolymerizable therewith as a binder, and (d) a filler and/or aggregate, is low in shrinkage and has excellent dimensional stability. The block copolymer mixture is obtained by firstly polymerizing vinyl acetate, or a styrene series monomer, and/or an acrylic acid ester and/or a methacrylic acid ester, in the presence of a polymerization initiator of a polymeric peroxide having the following general formula <IMAGE> to form a mixture of a copolymer having peroxy bonds in the molecule, and then copolymerizing the copolymer mixture with another monomer, to form a mixture of block copolymer and the component polymers. |