List of TOPAS® COC grades

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5. Molding characteristics

5.4 Thermal stability

(1) Characteristic changes by residence in cylinder

TOPAS® COC mold pieces usually turn yellow after residence in the cylinder. On the other hand, there is no great change in mechanical properties as shown in Fig. 5-14.

Fig. 5-14 Changes in tensile characteristic by residence in cylinder

(2) Characteristic changes by long-time high-temperature treatment

Fig. 5-15 - 18 shows changes in YI and Haze in the case where TOPAS molded products are high-temperature-treated. There seem to be tendencies of yellowing and hazing due to long-time high-temperature treatment.

Fig. 5-15 Changes in YI by 85°C heat treatment	Fig. 5-16 Changes in haze by 85°C heat treatment
Fig. 5-17 Changes in YI by 110°C heat treatment	Fig. 5-18 Changes in haze by 110°C heat treatment

(3) Characteristic changes by cylinder temperature

Figs. 5-19 to 5-22 show changes of 5013L-10 in some properties according to cylinder temperature. YI, Haze and bending elastic modulus change at 330°C or more. Basically, molding in the recommended condition range is advisable.

Fig. 5-19 Cylinder temperature and YI and Haze of 5013L-10

Fig. 5-20 Physical properties of 5013L-10 by cylinder temperature (tensile test)	Fig. 5-21 Physical properties of 5013L-10 by cylinder temperature (Charpy impact strength)
Fig. 5-22 Physical properties of 5013L-10 by cylinder temperature (bending test)