DESIGN OF CLARIFIED POLYPROPYLENE WITH A NOVEL CLARIFIER

摘要

Newly-developed "Advanced Clarifier" (AC) exhibited higher crystallization temperature, shorter crystallization half time resulting in providing a-form crystal, higher crystallization rate and degree of crystallinity. Lower molding temperature was found to be preferred to maximize the clarifying ability of AC. The clarifier improved haze effectively and provided excellent transparency even at lower loading levels around 0.1 wt%, and exhibited the superior clarity in thinner molded articles. Higher stiffness of 25%-increase in flexural modulus can be achieved by using the clarifier. Thus, AC gave most excellent balance between clarity and stiffness. Similar tendency was confirmed in film application. On the other hand, the haze of molded articles with the clarifier varied with a comonomer randomness referred as comonomer sequence distribution or run numbers. Polydispersity also affected the haze. Higher randomness and broader molecular weight distribution of polypropylene with AC provided superior transparency. This suggests that appropriate design of base resin in combination with the clarifier is suggested to be useful to design the clarified polypropylene. In summary, the AC is expected to diversify the design of clarified polypropylene and to expand the application range.