Carlsberg is one of many major international firms looking to change the way it packages products.

Earlier this week consumer goods giant Unilever said it would halve its use of virgin plastic by 2025.

Carlsberg has released details of two new “paper bottle” research prototypes it’s working on.

In an announcement made during the C40 World Mayors Summit in Copenhagen on Friday, the Danish brewing giant said the “Green Fibre Bottle” prototypes were produced from sustainably sourced wood fibres and “fully recyclable.”

The business has been developing the idea since 2015, working with packaging experts and academics on the project.

An “inner barrier” is used to ensure the bottles can carry beer. One prototype uses a recycled polyethylene terephthalate polymer film barrier, which acts as a thin internal lining. The other uses what Carlsberg described as a “100% bio-based” polyethylene furanoate polymer film barrier.

The prototypes will now be tested, with Carlsberg stating that its eventual aim was to produce a “100% bio-based bottle without polymers.”

In a statement Friday, Myriam Shingleton, the Carlsberg Group’s vice president, group development, said the firm was “pleased with the progress we’ve made on the Green Fibre Bottle so far.”

“While we are not completely there yet, the two prototypes are an important step towards realizing our ultimate ambition of bringing this breakthrough to market,” Shingleton added. The company would continue to work with experts to “overcome remaining technical challenges”, she said.

Carlsberg is one of many major international firms looking to change the way it packages products. Earlier this week consumer goods giant Unilever said it would halve its use of virgin plastic by 2025.

The business, whose brands include Dove, Ben & Jerry’s and Lipton, said it would achieve this by cutting its “absolute use of plastic packaging” by over 100,000 tonnes and “accelerating its use of recycled plastic.” Virgin plastics are produced using raw materials, rather than recycled ones.

“The way that we’ll reduce the virgin plastic in half is by, first, an absolute reduction in the amount of plastic that we use, and that’s going to require our best innovative capability to come up with different packaging formats,” Alan Jope, Unilever’s CEO, told CNBC’s Julianna Tatelbaum in an interview broadcast Monday.

“But also, we’re going to make much more use of recycled materials, stuff that the consumer has put into recycling streams and which we’re able to use,” Jope added. “And by doing that we hope to trigger the continued development of the recycled material business system.”