Development of resin-molding-releasing metal mold surface using perfluoroalkyl group-containing polymer plating

The resin-molding releasing properties of metal molds were shown to be rela ted to following factors: a) interfacial chemical bondings between surfaces of polymers and metal molds and b) a friction force or friction coefficien t between polar substances and/or low molecular weight components in the po lymers and physical factors on mold surfaces. It was confirmed theoreticall y and experimentally that metal molds with good resin-molding releasing pro perties have very small surface free energy. It was also proved that surfac e free energy in the resulting polymer molding was changed to be lower than that of before shaping. Molding releasing properties were improved with de crease in friction force and friction coefficient between surface of polyme rs and metal molds as well as decrease of surface free energy. To obtain metal molds with smaller surface free energy, the polymer plating method of perfluorinated group-containing triazinedithiol was developed. M etal molds treated by the polymer platings have lower critical surface tens ion of 7.5 mJ m(-2) than that of Teflon (18 mJ m(-2)), meaning that the sur face consists of CF3 groups. The treated mold showed more markedly excellen t durability in releasing properties than untreated one. The technique has been developed in the production of molds for F theta lens and natural brig ht focusing screen.