(19)

(11)

EP 4 085 161 A1

(12)

(43) Date of publication: 09.11.2022 Bulletin 2022/45 (21) Application number: 21700228.6 (22) Date of filing: 04.01.2021

(51) International Patent Classification (IPC):  D01F 2/28(2006.01) (52) Cooperative Patent Classification (CPC): D01F 2/28 (86) International application number: PCT/FI2021/050001 (87) International publication number: WO 2021/136885 (08.07.2021 Gazette 2021/27)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 03.01.2020 FI 20205006 (71) Applicant: Teknologian Tutkimuskeskus VTT OY 02150 Espoo (FI)	(72) Inventors: WILLBERG-KEYRILÄINEN, Pia 02044 VTT (FI) ROPPONEN, Jarmo 02044 VTT (FI) MALM, Tero 02044 VTT (FI) ROKKONEN, Teijo 02044 VTT (FI) HARLIN, Ali 02044 VTT (FI) (74) Representative: Laine IP Oy  Porkkalankatu 24 00180 Helsinki 00180 Helsinki (FI)