US 11,926,117 B2
MDO thermoresistant heat-shrinkable multilayer film
Seol-Hee Lim, Seoul (KR); Sung-Gi Kim, Gyeonggi-do (KR); and So-Yeon Kim, Daejeon (KR)
Assigned to SK Chemicals Co., Ltd., Gyeonggi-do (KR)
Appl. No. 16/344,120
Filed by SK CHEMICALS CO., LTD., Gyeonggi-do (KR)
PCT Filed Nov. 24, 2017, PCT No. PCT/KR2017/013546
§ 371(c)(1), (2) Date Apr. 23, 2019,
PCT Pub. No. WO2018/097656, PCT Pub. Date May 31, 2018.
Claims priority of application No. 10-2016-0157613 (KR), filed on Nov. 24, 2016.
Prior Publication US 2019/0329538 A1, Oct. 31, 2019
Int. Cl. B29D 7/01 (2006.01); B32B 27/08 (2006.01); B32B 27/20 (2006.01); B32B 27/36 (2006.01); B32B 37/15 (2006.01); B32B 38/00 (2006.01); C08J 5/18 (2006.01); C08L 67/02 (2006.01)
CPC B29D 7/01 (2013.01) [B32B 27/08 (2013.01); B32B 27/20 (2013.01); B32B 27/36 (2013.01); B32B 37/153 (2013.01); B32B 38/0012 (2013.01); C08J 5/18 (2013.01); C08L 67/02 (2013.01); B32B 2038/0028 (2013.01); B32B 2307/306 (2013.01); B32B 2307/516 (2013.01); B32B 2307/736 (2013.01); C08J 2367/02 (2013.01); C08J 2467/02 (2013.01); C08L 2201/08 (2013.01); C08L 2203/16 (2013.01); C08L 2205/025 (2013.01); C08L 2205/03 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An MDO thermoresistant heat-shrinkable multilayer film comprising:
a substrate layer, and
a skin layer on at least one of the upper and the lower sides of the substrate layer,
wherein the substrate layer and the skin layer each consist of a copolymer polyester resin, which is formed by copolymerization of an acid component comprising terephthalic acid and a diol component, and has a structure wherein an acid moiety derived from the acid component and a diol moiety derived from the diol component are repeated,
wherein the diol component in the substrate layer comprises diethylene glycol, ethylene glycol, and one or more monomers selected from the group consisting of 1,4-cyclohexanedimethanol and neopentyl glycol,
wherein the diol component in the skin layer comprises 1,4-cyclohexanedimethanol, diethylene glycol, ethylene glycol, and isosorbide, and
wherein the content of the isosorbide in the skin layer is 1 mol % to 60 mol % based on the total diol components included in the skin layer,
wherein the substrate layer does not comprise isosorbide as the diol component,
wherein the glass transition temperature (Tg) of the copolymer polyester resin included in the skin layer is 85° C. or more, and the Tg of the copolymer polyester resin included in the substrate layer is 70° C. to 80° C., and
wherein the film is prepared by stretching it by 2 to 5 times in the MD (machine direction),
wherein a maximum heat shrinkage of the film in the MD at 95 to 100° C. is 50% or more, and a shrinkage of the film in the transverse direction (TD) at 100° C. is 5% or less,
wherein a shrink initiation temperature of the film is 70° C. or more,
wherein the film has haze of 5% or less, and
wherein the total thickness of the film is 10 to 60 μm.