Rotational-Molded LLDPE Automotive Fuel Tanks

Rotational-Molded LLDPE Automotive Fuel Tanks [Pg.244]

In-line and nowadays postfluorinated HDPE fuel tanks have been used for many years without any problems in Europe. These tanks comply with European l.ECE Regulation 34 Appendix 5 as well as with the SHED (Sealed House Emission Determination) tests.17 [Pg.244]

In South Africa, owing to the diversity and small production volume of specific motor car models, it is not economically feasible to blow-mold HDPE fuel tanks. The only cost-effective plastic tank manufacturing process used in South Africa is rotational molding, using LLDPE with a density of 0.939 g/cm3. Some selected properties of LLDPE before and after petrol exposure are compared to HDPE in Table 16.2. It is clear that owing to weaker mechanical properties, LLDPE is far less suitable than HDPE for petrol containment, mainly because of its lower crystallinity. [Pg.244]

By a combination of tank redesign and surface fluorination the problems were overcome and today a number of local motor car manufacturers are using surface-fluorinated LLDPE petrol tanks. These tanks performed exceptionally well in petrol permeation tests in which control tanks lost about 16g/day, while fluorinated tanks lost less than 0.5g/day at 40°C. With advanced fluorination techniques mass loss values of less than 0.1 g/day have already been achieved for some of these fluorinated tanks. [Pg.244]

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