US 12,240,211 B2
Polyester sealant film, laminate and package
Shintaro Ishimaru, Tsuruga (JP); and Masayuki Haruta, Tsuruga (JP)
Assigned to TOYOBO CO., LTD., Osaka (JP)
Appl. No. 16/481,826
Filed by TOYOBO CO., LTD., Osaka (JP)
PCT Filed Feb. 8, 2018, PCT No. PCT/JP2018/004341
§ 371(c)(1), (2) Date Jul. 29, 2019,
PCT Pub. No. WO2018/150997, PCT Pub. Date Aug. 23, 2018.
Claims priority of application No. 2017-025966 (JP), filed on Feb. 15, 2017.
Prior Publication US 2021/0101379 A1, Apr. 8, 2021
Int. Cl. B32B 27/36 (2006.01); B32B 1/00 (2024.01); B32B 7/027 (2019.01); B32B 27/08 (2006.01); B65D 65/40 (2006.01)
CPC B32B 27/36 (2013.01) [B32B 1/00 (2013.01); B32B 7/027 (2019.01); B32B 27/08 (2013.01); B65D 65/40 (2013.01); B32B 2250/02 (2013.01); B32B 2250/244 (2013.01); B32B 2307/306 (2013.01); B32B 2307/31 (2013.01); B32B 2307/518 (2013.01); B32B 2439/06 (2013.01); Y10T 428/13 (2015.01); Y10T 428/1328 (2015.01); Y10T 428/1331 (2015.01); Y10T 428/1334 (2015.01); Y10T 428/1345 (2015.01); Y10T 428/1352 (2015.01); Y10T 428/1397 (2015.01)] 8 Claims
OG exemplary drawing
 
1. A polyester sealant film consisting of a two-kind two-layer structure of a heat sealing layer and a heat resistant layer, wherein both the heat sealing layer and the heat resistant layer consist of a polyester component which comprises ethylene terephthalate as a main component, and wherein the polyester sealant film satisfies following requirements (1) to (6):
(1) a heat sealing strength of the heat sealing layer being heat-sealed to another heat sealing layer of an identical polyester film at 140° C. and 0.2 MPa for 2 seconds is 8 N/15 mm or more and 20 N/15 mm or less;
(2) the heat sealing layer has a difference in reversible heat capacity (ΔCp) between a glass transition temperature and 140° C. of 0.61 J/g/K or more and 1.1 J/g/K or less when measured with a temperature modulated DSC;
(3) the heat resistant layer has a ΔCp of 0.1 J/g/K or more and less than 0.6 J/g/K when measured with the temperature modulated DSC;
(4) the film has a fold holding angle of 20 degrees or more and 60 degrees or less;
(5) the film has a curvature radius of 50 mm or more and 300 mm or less in either a longitudinal direction or a widthwise direction, whichever has a smaller curvature radius; and
(6) the film has a heat shrinkage ratio of −5% or more and 5% or less in both a longitudinal direction and a widthwise direction after immersed in hot water of 80° C. for 10 seconds,
wherein
the polyester component constituting the heat sealing layer comprises a diol monomer component other than ethylene glycol as a monomer component,
the polyester component constituting the heat resistant layer comprises a diol monomer component other than ethylene glycol as a monomer component;
the content of the diol monomer component in the heat sealing layer is 32% or more by mol and 50% or less by mol;
the content of the diol monomer component in the heat resistant layer is 9% or more by mol and 20% or less by mol; and
a difference of the content of the diol monomer component between the heat sealing layer and the heat resistant layer is 20% or more by mol and 35% or less by mol.