US 11,993,737 B2
Surface protection film
Yutaka Kamada, Hyogo (JP); Arata Tani, Hyogo (JP); Toshihiko Horie, Saitama (JP); and Soh Kato, Saitama (JP)
Assigned to BANDO CHEMICAL INDUSTRIES, LTD., Hyogo (JP)
Appl. No. 16/618,162
Filed by BANDO CHEMICAL INDUSTRIES, LTD., Hyogo (JP)
PCT Filed May 29, 2018, PCT No. PCT/JP2018/020485
§ 371(c)(1), (2) Date Nov. 29, 2019,
PCT Pub. No. WO2018/221490, PCT Pub. Date Dec. 6, 2018.
Claims priority of application No. 2017-107569 (JP), filed on May 31, 2017.
Prior Publication US 2020/0339840 A1, Oct. 29, 2020
Int. Cl. C09J 7/29 (2018.01); B32B 7/12 (2006.01); B32B 27/36 (2006.01); B32B 27/40 (2006.01); C09J 7/20 (2018.01); C09J 7/25 (2018.01); C09J 7/40 (2018.01); G02B 1/14 (2015.01)
CPC C09J 7/29 (2018.01) [B32B 7/12 (2013.01); B32B 27/36 (2013.01); B32B 27/40 (2013.01); C09J 7/201 (2018.01); C09J 7/25 (2018.01); C09J 7/405 (2018.01); G02B 1/14 (2015.01); B32B 2307/748 (2013.01); B32B 2571/00 (2013.01); C09J 2203/326 (2013.01); C09J 2475/006 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A surface protection film, comprising:
a protective layer made of a polyurethane on an outermost surface thereof,
wherein the polyurethane has an international rubber hardness degree (IRHD) of 87.0 or more and 98.0 or less, a tan δ peak value of 0.6 or more and 1.39 or less, and a tan δ peak temperature of −20° C. or more and 36.2° C. or less, the protective layer has a thickness of 150 μm or more and 300 μm or less, and
the polyurethane is a thermally cured product of a material composition comprising at least a polyol, an isocyanate, and an alcohol curing agent,
the alcohol curing agent comprises 60 to 80 parts by weight of dihydric alcohol and 40 to 20 parts by weight of trihydric alcohol, and
a ratio (—OH/—NCO) between a number of moles of hydroxyl groups (—OH) contained in the alcohol curing agent and a number of moles of isocyanate groups (—NCO) of the isocyanate in which the polyurethane is not thermally cured is 1.05 or more and 1.3 or less.