US 12,454,120 B2
Polyethylene film having multi-layer structure and packaging material produced using the same
Eunjung Baek, Daejeon (KR); Soyoung Park, Daejeon (KR); Daesig Hong, Daejeon (KR); Joohyun Nam, Daejeon (KR); Jaemyoung Son, Daejeon (KR); and Byoungcheon Jo, Daejeon (KR)
Assigned to SK Innovation Co., Ltd., Seoul (KR); and SK Geo Centric Co., Ltd., Seoul (KR)
Appl. No. 18/551,273
Filed by SK Innovation Co., Ltd., Seoul (KR); and SK Geo Centric Co., Ltd., Seoul (KR)
PCT Filed Jun. 7, 2022, PCT No. PCT/KR2022/007978
§ 371(c)(1), (2) Date Sep. 19, 2023,
PCT Pub. No. WO2022/260384, PCT Pub. Date Dec. 15, 2022.
Claims priority of application No. 10-2021-0075620 (KR), filed on Jun. 10, 2021.
Prior Publication US 2024/0157687 A1, May 16, 2024
Int. Cl. B32B 27/08 (2006.01); B32B 7/02 (2019.01); B32B 27/32 (2006.01); B65D 65/40 (2006.01); C08F 110/02 (2006.01)
CPC B32B 27/08 (2013.01) [B32B 7/02 (2013.01); B32B 27/32 (2013.01); B65D 65/40 (2013.01); C08F 110/02 (2013.01); B32B 2250/03 (2013.01); B32B 2250/04 (2013.01); B32B 2250/05 (2013.01); B32B 2255/10 (2013.01); B32B 2255/28 (2013.01); B32B 2307/31 (2013.01); B32B 2307/558 (2013.01); B32B 2307/72 (2013.01); B32B 2307/7376 (2023.05); B32B 2323/043 (2013.01); B32B 2323/046 (2013.01); B32B 2439/46 (2013.01); B32B 2439/70 (2013.01); B65D 2565/385 (2013.01); B65D 2565/386 (2013.01)] 15 Claims
 
1. A polyethylene film comprising a multi-layer structure, comprising:
an outer layer (A) comprising a first ethylene polymer having a density M1 of 0.935≤M1≤0.968;
an intermediate layer (B) comprising a second ethylene polymer having a density M2 of 0.900≤M2≤0.920; and
an inner layer (C) comprising a third ethylene polymer having a density M3 of 0.850≤M3≤0.885,
each density being measured according to ASTM D-792, and a unit of each density is g/cm3,
wherein the outer layer (A), the intermediate layer (B), and the inner layer (C) are sequentially laminated to form the polyethylene film comprising the multi-layer structure,
wherein a falling ball impact strength per unit thickness of the polyethylene film comprising the multi-layer structure according to ASTM D 1709 is 3.0 to 15.0 g/μm, and a puncture strength per unit thickness of the polyethylene film comprising the multi-layer structure is 0.2 to 0.4 N/μm obtained by measuring a maximum strength when the film is ruptured by a pin having a diameter of 6.5 mm that punctures the film in an inner surface direction at a speed of 500 mm/min, and the falling ball impact strength and the puncture strength per unit thickness refer to numerical values obtained by dividing the falling ball impact strength and puncture strength values measured according to the above methods by a total thickness of the film, respectively, and wherein a difference in melting point between the outer layer (A) and the inner layer (C) is 55 to 90° C. and the melting point of the inner layer (C) is 80° C. or lower, and wherein a molecular weight distribution of the first ethylene polymer is 3 to 10, and a molecular weight distribution of the second ethylene polymer and the third ethylene polymer is 1 to 5.