US 11,981,519 B2
Biaxially oriented polyester film roll
Nobuyuki Manabe, Inuyama (JP); and Masayuki Haruta, Inuyama (JP)
Assigned to TOYOBO CO., LTD., Osaka (JP)
Appl. No. 17/285,777
Filed by TOYOBO CO., LTD., Osaka (JP)
PCT Filed Oct. 25, 2019, PCT No. PCT/JP2019/041984
§ 371(c)(1), (2) Date Apr. 15, 2021,
PCT Pub. No. WO2020/090673, PCT Pub. Date May 7, 2020.
Claims priority of application No. 2018-203615 (JP), filed on Oct. 30, 2018.
Prior Publication US 2021/0339973 A1, Nov. 4, 2021
Int. Cl. B65H 18/28 (2006.01); B29C 48/00 (2019.01); B29C 48/08 (2019.01); B29C 48/28 (2019.01); B29K 67/00 (2006.01); C08J 5/18 (2006.01); C08K 3/36 (2006.01)
CPC B65H 18/28 (2013.01) [C08J 5/18 (2013.01); B29C 48/0018 (2019.02); B29C 48/08 (2019.02); B29C 48/28 (2019.02); B29K 2067/003 (2013.01); B65H 2701/1752 (2013.01); C08J 2367/02 (2013.01); C08K 3/36 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A polyester film roll obtained by winding a biaxially oriented polyester film around a core, wherein
the biaxially oriented polyester film consists of polyethylene terephthalate and particles formed of silica,
the content of the silica in the biaxially oriented polyester film is 100 ppm by weight or more and 20,000 ppm by weight or less,
the weight average particle size of the silica measured by a Coulter counter is 0.05 μm to 3.0 μm,
the biaxially oriented polyester film has a thickness of 5 μm or more and 40 μm or less,
an average winding hardness on a surface of the polyester film roll is in a range of 500 or more and 700 or less,
a variation rate of a winding hardness on a surface of the polyester film roll in a film transverse direction is 1% or more and 5% or less,
a variation rate of an average winding hardness from a surface of the polyester film roll to the core is 3% or more and 10% or less,
static friction coefficient on each of a winding outer surface and a winding inner surface of the biaxially oriented polyester film is 0.2 or more and 0.60 or less, and
arithmetic mean height on a winding inner surface of the biaxially oriented polyester film is 0.010 μm or more and 0.050 μm or less.