Samsung may be the first to release a foldable phone next year, according to some reports, but it won’t be the only top company looking to launch such devices. A new report says that foldable smartphones are in the works from several tech giants, Apple included, and they may become more and more popular by 2019. But could Apple release its first foldable iPhone as soon as 2018?

To make a foldable phone, you need a flexible display, and a flexible type of glass. OLED is flexible, whereas LCD isn’t, and Apple is already expected to launch its first OLED iPhone with a curved display next year.

According to The Korea Herald, there’s just one company in the world that can mass produce colorless polyimide, the glass that would protect the foldable OLED screen, and that’s Kolon Industries.

“Around three to five tech companies are expected to mass produce foldable phones in 2018 globally. The devices will then grab around 20 percent of the total smartphone market here,” Kolon Industries’ colorless polyimide division head Kang Chung-seok told The Herald.

The company is apparently supplying materials to Samsung, LG, and BOE. Apple may also be one of the companies looking at such components.

The Kolon exec said the first foldable devices could have a bend radius of 5 millimeters rather than the 1-millimeter radius that would allow a wallet-like smartphone fold, where the glass on the face of the handset would actually touch itself.

“The bend radius of 1 millimeter is the most ideal, but that may cause a safety issue. So, tech companies are likely to unveil the bend radius of 5 millimeters first and then gradually unveil devices with less bend radius,” Kang added.

Kolon finished the development of its flexible colorless polyimide glass in August and expects to mass produce films for around 100 million units of foldable devices in 2018.

Apple has traditionally been very cautious about adopting certain technologies, choosing to only bring some of them to market in the iPhone when they have met its performance and quality standards. It’ll be interesting to see how fast the company will release a foldable iPhone — or iPad, for that matter — especially considering that the iPhone will receive it’s first major redesign in four iPhone generations next year.

That said, Apple already has various patents describing foldable devices, including the kind fold just like a wallet.