North American prices for polypropylene and polystyrene resins moved in different directions in March, with PP prices dropping while PS prices increased.
PP prices were down an average of 4 cents per pound in March after being up by that same amount in February. Prices for the material had increased 5 cents in January.
Price changes for PP again followed movements in price for polymer-grade propylene feedstock, but were influenced by larger macroeconomic factors as well.
"Supply [of PP] is ample, and demand is weak, but showing signs of improvement," said Howard Rappaport, a market analyst with StoneX in New York. He added there's "plenty of [PP] market uncertainty over the implementation of tariffs."
According to Rappaport, that's because PP has a more diverse end-use base — including automotive, appliance, medical and electronics — and is susceptible to wide reaching regional tariffs.
Regional PS prices surprised some market watchers by increasing an average of 2 cents per pound in March. Prices for the material had been flat in February after moving up 3 cents in January.
The March PS increase took hold even though prices for benzene feedstock were flat for the month. Benzene is used to make styrene monomer, and as a result has an influence on PS prices.
One market watcher contacted by Plastics News pointed out that other materials such as ethylene and rubber also impact PS prices.
"In this case [for March], the higher price corresponds with some catch up on raw material increases that were not fully covered by resin over the last few months," he added.