US 11,865,818 B2
Multilayer structure
Nina Ackermans, Tessenderlo (BE); Paulo Cavacas, Coutada (PT); Willem De Wever, Hasselt (BE); and Auli Nummila-Pakarinen, Porvoo (FI)
Assigned to Borealis AG, Ludwigshafen am Rhein (DE)
Filed by BOREALIS AG, Vienna (AT)
Filed on Aug. 23, 2022, as Appl. No. 17/893,408.
Application 17/893,408 is a division of application No. 16/303,837, granted, now 11,472,166, previously published as PCT/EP2017/060896, filed on May 8, 2017.
Claims priority of application No. 16172879 (EP), filed on Jun. 3, 2016.
Prior Publication US 2022/0402252 A1, Dec. 22, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. B32B 27/08 (2006.01); B32B 7/12 (2006.01); B32B 27/30 (2006.01); B32B 27/32 (2006.01); B32B 7/03 (2019.01); B32B 37/10 (2006.01); B29C 48/21 (2019.01); B32B 37/15 (2006.01); B29C 48/154 (2019.01); B29C 48/00 (2019.01); B32B 38/00 (2006.01); B29K 23/00 (2006.01); B29C 48/92 (2019.01)
CPC B32B 27/08 (2013.01) [B29C 48/154 (2019.02); B29C 48/21 (2019.02); B32B 7/12 (2013.01); B32B 27/30 (2013.01); B32B 27/306 (2013.01); B32B 27/32 (2013.01); B32B 27/327 (2013.01); B32B 37/153 (2013.01); B29C 48/0018 (2019.02); B29C 48/92 (2019.02); B29C 2948/92704 (2019.02); B29C 2948/92876 (2019.02); B29K 2023/06 (2013.01); B29K 2023/086 (2013.01); B32B 2038/0028 (2013.01); B32B 2250/05 (2013.01); B32B 2250/246 (2013.01); B32B 2307/516 (2013.01); B32B 2307/518 (2013.01); B32B 2307/7244 (2013.01); B32B 2307/7246 (2013.01); B32B 2309/02 (2013.01)] 19 Claims
 
1. A process for producing a multilayer structure comprising (i) a first polyethylene layer as a first external layer, the first polyethylene layer being oriented in at least machine direction; (ii) a second polyethylene layer as a second external layer; (iii) a layer made of a copolymer of ethylene and vinyl alcohol (EVOH) between the first external layer and the second external layer; and (iv) a tie layer on each side of the EVOH layer, wherein the tie layers comprise one or more copolymers of ethylene, the process comprising: (I) providing a substrate, wherein the substrate is a polyethylene film which has been oriented in at least machine direction; (II) coextruding onto the substrate (II-1) a layer of a copolymer of ethylene and vinyl alcohol; (II-2) a second polyethylene layer; and (II-3) tie layers on both sides of the layer of the copolymer of ethylene and vinyl alcohol, wherein the layer of the copolymer of ethylene and vinyl alcohol is between the substrate and the second polyethylene layer, thereby producing the multilayer structure.