Blow molding process

A process for producing a molded product having excellent heat resistance, which comprises:

• forming a composition comprising a crystalline polyamide by mixing together (a) 50-90% by weight of a hexamethylene adipamide component, (b) 5-40% by weight of a hexamethylene terephthalamide component and (c) 5-30% by weight of a hexamethylene isophthalamide component, based on the weight of the crystalline polyamide,
• forming a melt polymer from said composition and applying shear to said melt polymer, the melting point (Tm) and crystallization temperature (Tc) of the crystalline polyamide being Tm.gtoreq.225.degree. C. and Tc.ltoreq.230.degree. C., respectively, and the melt viscosity of said crystalline polyamide varying greatly depending on the shear rate applied to said melt polymer and satisfying formulae (I) and (II):
• 2,000,000.gtoreq..mu.a10.gtoreq.2,000 (I)
• .mu.a10/.mu.a1000.gtoreq.3.3. (II)
• wherein:
• Tm:
• melting point of said polyamide (.degree.C.)
• .mu.a10:
• melt viscosity at a temperature of Tm+20.degree. C. and a shear rate of 10 (1/sec) (poise)
• .mu.a1000:
• melt viscosity at a temperature of Tm+20.degree. C. and a shear rate of 1000 (1/sec) (poise);
• and
• forming a parison from said melt polymer and blow molding the parison to form said molded product.