A study was carried out to prove a varidity of the new principle to prevent the growth of scumming on the surface of the low profile SMC moldings. Styrene-divinylbenzene (ST-DVB) polymers were prepared by suspension polymerization and used as additive polymer for low profile SMC. These SMC were molded and evaluated with special emphasis on the mold scumming, shrinkage and surface waveness. As the results, it was confirmed that the optimum content of DVB was 0.2% by weight for ST, the low profile moldings were obtained without scumming whenever loosely cross linked additive polymer containing 0.2% DVB [I] were used for the unsaturated polyesters [II] including vinylesters and to get around producing minute surface wave of moldings, the desirable particle size was under 50 μm. The physical anchloring principle would be able to applied to the SMC containing various types of [I] and any kind of [II] to obtain scammingless moldings.
Cylinder tester which can apply circumferencial stress, axial stress and torsional moment simultaneously using cylinder-shaped coated fabric specimen was made by the authors. The torsional angle-torsional moment responses of three kinds of coated plain weave fabric subjected to small circumferencial and axial stress were studied. The torsional response of the material was approximately linear. Assuming the specimen was a cylindrically elastic material, a simple expression for practical calculation of shear elastic coefficient was obtained. The coefficient of respective specimens was calculated using the expression. The shear coefficient of PTFE coated material was about six times of that of PVC coated material.