Global plastic caps and closures demand is set to increase 4.1% per year to nearly 1.9 trillion units in 2021, according to the latest report by market research company the Freedonia Group.

The report, titled “Global plastic caps & closure market”, projected that gains will be driven by bottled water, which has become the largest application for plastic closures.

The bottled water market, according to the report, also offers the greatest growth opportunities through 2021.

Threaded plastic caps and closures accounted for the largest share of plastic caps and closures demand in 2016 and are expected to hold 67% of the market in 2021, the Cleveland-based industry research firm said.

Competition from value added closure types such as dispensing and child-resistant varieties, will however, be impacting the industry.

“Dispensing caps are becoming increasingly popular in applications once dominated by standard threaded caps, such as single-serve bottled water and sports drinks,” the group added.

These beverages are often packaged in plastic bottles featuring flip-top or push-pull caps that enable easy, on-the-go dispensing without requiring the removal of the cap.

According to the report, the Asia-Pacific region is expected to see the fastest demand growth globally.