WEB EXCLUSIVE: Two new materials were presented at the recent SPE Annual Blow Molding Conference in Chicago. One is a new grade of polyarylamide (MXD6 nylon) for blow molded fuel tanks. Ixef BXT 2000-0203 from Solvay Advanced Polymers LLC, Alpharetta, Ga., is said to provide excellent fuel barrier and good chemical resistance. It can be processed on continuous-extrusion, accumulator-head, reciprocating-screw, and suction blow molding machines. It can also be coextruded with other nylons and polyolefins. It has a 6 MFR and specific gravity of 1.12. Melting point is 446 F, crystallization temperature is 266 F, and glass-transition point is 203 F.
A new grade of HDPE for injection stretch-blow molding (ISBM) was discussed in a paper from Total Petrochemicals USA, Houston. SB 1359 (0.959 g/cc) and a companion European grade, SB 1461, were tailored specifically for ISBM, a process that is attracting global interest for milk bottles and packaging for household industrial chemicals (HICs), according to Michael A. McLeod, technical service manager for molding and sheet, and author of the SPE paper. According to Total, ISBM can permit up to 20% lightweighting of HDPE bottles compared with extrusion blow molding (EBM), along with lower haze, higher gloss, and absence of weld lines or flash trimming. ISBM brings other benefits, such as superior neck finish and much higher machine productivity—up to 60,000 bottles/hr, equal to PET throughput. This reportedly comes with no loss of top-load or drop-impact strength compared with EBM. HDPE is said to process easily on ISBM equipment for PET, but HDPE does not require drying, has higher topload strength, and facilitates recycling because the cap and container can be of the same material.
McLeod’s paper showed that the specially tailored HDPE gave better and faster processing by ISBM than a standard 8 MI2 injection-grade HDPE. He also presented an example of a 1L milk bottle processed at 2000 bottles/mold/hr on a Sidel SBO Universal ISBM machine. The ISBM HDPE container weighed 22 g, vs. 28 or 32 g for two commercial EBM HDPE bottles.