Polystyrene (PS) is one of the world’s oldest and most widely used thermoplastic polymers. It can be solid or foam, and it is made from styrene monomer. PS is available in several forms – general purpose (crystal), medium impact and high impact (HIPS).
PS has good processing properties and is used in many applications, including food packaging, domestic appliances, electronic goods, toys, household items, furniture and foams for construction.
It faces competition from other plastics as substitutes. For example, in food packaging some producers have switched to alternatives such as paper.
In consumer electronics, other plastics such as acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) have replaced a portion of PS usage.
Peak demand in the US PS market is typically scattered throughout the year during March, June and October. Demand during the first six months of 2016 hit low points in January and May.
Year to date, US, Canadian and Mexican PS sales/captive use was down by 1.5% in June. Food and packaging are by far the largest end use sectors for PS, accounting for 62% of total sales/captive use in June.
US PS exports during the first six months of 2016 at 81,487 tonnes were up by 26% from the same period the previous year. Primary export destinations include Mexico and Canada. The two countries accounted for 90% of total exports during the first half of 2016. The US imported 67,164 tonnes of PS during the first half of 2016, which was up by 33% year on year.
Mexico, the largest supplier to the US, accounted for 58% of total imports during the first six months of 2016.
Total Petrochemicals conducted a turnaround at its 658,000 tonne/year PS plant in Carville, Louisiana, in March.
The producer also declared force majeure at the end of June after its reactors lost power. The plants were down for about six weeks.
US PS prices have been largely flat since the beginning of August 2015. Since then, prices rose twice, dropped twice and rolled over in all of the other months.
Prices increased by 5 cents/lb in April. August prices firmed by an average of 1 cent/lb after three producers separately announced prices increases of 2 cents/lb.
PS prices typically follow the direction of US benzene contract prices closely, but other factors such as supply and demand also help determine prices.
Since the beginning of September 2015, benzene has traded within a narrow range of $1.77/gal to $2.30/gal. That has had a lot to do with the price stability in the PS market.
PS was first commercially produced by polymerisation of styrene feedstock in the 1930s. The two main types of polymers produced are a clear, crystal amorphous resin, known as general purpose polystyrene (GPPS), and an impact resin, known as high impact polystyrene (HIPS), which contains varying levels of polybutadiene.
Three processes generally used are the solution route, with the advantages of producing low residual monomer content and high-purity polymers; the suspension route, which produces polymers of different molecular weights and can thus make specialist crystal and high-impact grades of PS; and mass (bulk) polymerisation, the advantages of which are the clarity and excellent colour of the resins produced.
Global PS demand is expected to grow by an average of 4.5% from 2015 to 2020, led by rising demand from the packaging industry in developing countries, as well as increasing demand from consumer electronics, according to Zion Research.
Growth rates in the US, however, are much lower, with little or no growth seen for the market in 2016-2017, according to market participants. There will likely be demand shifts in market segments, but the overall market is expected to be flat.
Food packaging and food service continue to be the primary market segment in North America, accounting for 63% of total demand during the first half of 2016 – up from 62% during the same period in 2015.
US exports are expected to continue to climb in order to meet the rising demand from developing countries. After the first half of the year, US PS exports in 2016 were on pace to hit the highest level since 2013.
PS recycling is expected to open new growth opportunities for the industry. However, environmental concerns, fluctuating raw material prices and the increased usage of substitute materials are expected to present ongoing challenges to the PS industry.
This will affect the growth of the industry in years to come.