1968 年 17 巻 176 号 p. 433-437
Polyesters from phthalic anhydride (I) and glycerol (II) (mole ratio of I/II=3/2 (A), 1/1 (B)), polyesters from I, II and diethylene glycol (III) (mole ratio of I: II: III=6:2:3 (C), 2:1:1 (D), 3: 2:1(E)) were prepared at 180°C under atmosphere of nitrogen, and acid values, softening points and reduced viscosities of these polyesters, were measured. The softening points of polyesters composed of (I) and (II) were higher than those of 3 component (I, II, III) polyesters. The softening points were lower in order of A, B, C, E, D and F.
After curing of two aluminium plates bonded with the above polyesters at 140±2°C and 180±2°C for 1, 2, 3 and 4 hours, the comparative shear strength of the resins for bonding metals was measured. From the results it was concluded that the strength of the 3 component system was generally higher than that of 2 component ones, and strength after curing at 180°C was markedly higher than that after curing at 140°C. When curing temperature was 140°C, C, F, and D were stronger as compared with A, B and E. When curing temperature was 180°C, D and F were very strong and became weaker in order of C and E, and B and A had the lowest strength. For both the 2 and 3 component systems, it was concluded that the bond strength decreased as glycerin content increased.