Styrolution cited feedstock price increases in the letter, sent Tuesday.
The feedstock benzene contract price for May rose 11 cents/gal ($33/mt) to a settlement at $4.47/gal ($1,337/mt), sources said.
Styrolution's price hike followed one Monday by Americas Styrenics for the transaction price for all grades of Styron polystyrene by 4 cents/lb, effective Wednesday.
In its letter Monday, Americas Styrenics cited high seasonal demand and low inventories as well as recent changes in feedstock, operating and logistical costs.
The increases came after US polystyrene prices fell 3 cents in April from March.
