SK Innovation to enter the 'transparent PI' business, the key material for foldable phones

SK Innovation has been speeding up their high-tech materials business. It has entered the transparent polyimide (PI) business, which plays a key role in implementing foldable displays. Transparent PI can replace glass, which is a conventional cover window. Sumitomo Chemical, Kolon Industries, LG Chem, and SKC are involved in the transparent PI business. Competition is expected to become more intense.

SK Innovation announced on 30th that it will develop and commercialize a transparent PI film. It will invest about 40 billion won in the site of the Li-ion battery separator (LiBS) plant in Chungpyeong-do, Chungcheongbuk-do, and construct a transparent PI film mass-production plant. The company plans to start operation in the second half of 2019 and to prepare pilot facilities first.

Since 2010, SK Innovation has started developing transparent PI-based on PI (polyimide) technology accumulated through mass production of related materials. It has also developed a special hard coating (HC) technology and a functional coating technology for fingerprint and contamination prevention so that even when folded tens of thousands of times, there are no broken or folded marks.

SK Innovation said, "The advantage is that we can provide a total solution from transparent PI manufacturing to hard coating and functional coating." And it was explained that “SK Innovation has secured differentiated competitiveness based on the accumulated material development capabilities such as LiBS, which ranks second in global market share"

Transparent PIs cannot be used on foldable phones by themselves. Hard coating is applied to the top or bottom to compensate for the low hardness. The harder the hard coating is, the more the hardness increases; however, it can also break more easily when folded. Thus, it is necessary to adjust the thickness and the hardness well. SK Innovation plans to follow the lead manufacturer with hard coating and special coating technology along with transparent PI.

"It is a small business now, but we will contribute to the development of the display industry and innovation of the business model of SK Innovation," said Roh Jae-seok, head of SK Innovation Materials Division. SK Innovation will participate in 'CES 2019' held in Las Vegas, the USA from January 8th, and announce plans for transparent PI, and plan to expand into the domestic and overseas market.

According to market researcher Strategy Analytics (SA), foldable smartphone shipments are projected to reach 50 million units in 2022 from 3 million units in 2019.