(PGPI) data showed petrochemical prices were up 2.3% from the September 2012 average of $1357/tonne. The PGPI is a benchmark basket of seven widely used petrochemicals and is published by Platts.

Olefins were mixed, with a 4% year-over-year decline in ethylene, while propylene prices rose 13% year over year. Platts noted that global propylene prices were supported by the €110/tonne ($141/tonne) rise in European contract prices over the last four months. Those increases were due to stronger polypropylene demand, plant outages, and persistently strong naphtha prices.

Shahrin Ismaiyatim, Platts editorial director, petrochemicals analytics, did note that the trend may be shifting. "However, early indicators of October price patterns are indicating that the rise in propylene prices may have reached its peak."  

Ethylene posted a $31/tonne rise in September to $1292/tonne, up 2% from July. Meanwhile, propylene prices averaged September at $1367/tonne, up $18/tonne or 1% month over month.

Polymer prices posted modest gains in September as Chinese buyers restocked inventories ahead of a week-long holiday in October. In addition, polyethylene suppliers to Latin America cited optimism in the polymers markets ahead of Brazil decreasing its polyethylene import tariff from 20% to 14% from October 1.

China's General Administration of Customs showed August imports of low-density polyethylene were up 6% from July, while imports of other grades of polyethylene showed decreases. 

The Platts Global low-density polyethylene index climbed 2% in September to $1663/tonne, up from $1628/tonne in August. The Platts Global polypropylene index was also up 2% in September to $1618/tonne, up from $1588/tonne in August.