US 12,290,974 B2
Biaxially oriented polypropylene film for heat sealing
Ling Fan, Geleen (NL); Hongtao Shi, Geleen (NL); Maria Soliman, Geleen (NL); Shan Qin, Geleen (NL); Shengming Cui, Geleen (NL); Priya Garg, Geleen (NL); and Jacobus Christinus Josephus Franciscus Tacx, Geleen (NL)
Assigned to SABIC GLOBAL TECHNOLOGIES B.V., Bergen op Zoom (NL)
Appl. No. 17/285,218
Filed by SABIC GLOBAL TECHNOLOGIES B.V., Bergen Op Zoom (NL)
PCT Filed Oct. 17, 2019, PCT No. PCT/EP2019/078184
§ 371(c)(1), (2) Date Apr. 14, 2021,
PCT Pub. No. WO2020/083738, PCT Pub. Date Apr. 30, 2020.
Claims priority of application No. 18202274 (EP), filed on Oct. 24, 2018.
Prior Publication US 2022/0001588 A1, Jan. 6, 2022
Int. Cl. B29C 48/21 (2019.01); B29C 48/00 (2019.01); B29C 48/08 (2019.01); B29K 23/00 (2006.01)
CPC B29C 48/21 (2019.02) [B29C 48/0018 (2019.02); B29C 48/022 (2019.02); B29C 48/08 (2019.02); B29K 2023/0608 (2013.01); B29K 2023/08 (2013.01); B29K 2023/12 (2013.01); B29K 2995/0053 (2013.01); B29K 2995/0063 (2013.01)] 16 Claims
 
1. A film comprising multiple co-extruded film layers, the film having a length and a width, and a thickness defined as the dimension of the film perpendicular to the plane defined by the length and the width,
wherein the film is a bi-axially oriented film comprising at least a core layer A, having a first and a second surface, and one or two sealing layer(s) B,
wherein the core layer A comprises a polypropylene,
wherein each of the one or two sealing layer(s) B comprises >50.0 wt % of a polyethylene comprising moieties derived from ethylene and moieties derived from an α-olefin comprising 4 to 10 carbon atoms, the polyethylene having a density of ≥870 and ≤920 kg/m3 as determined in accordance with ASTM D1505 (2010), with regard to the total weight of each of the one or two sealing layer(s) B,
wherein each of the one or two sealing layer(s) B directly adheres to one of the first or second surface of the core layer A, and
wherein the polyethylene has:
a fraction of material that is eluted in analytical temperature rising elution fractionation (a-TREF) at a temperature ≤30.0° C. of ≥5.0 wt %, with regard to the total weight of the polyethylene;
a shear storage modulus G′ determined at a shear loss modulus G″=5000 Pa of >1000 Pa, G′ and G″ being determined in accordance with ISO 6721-10 (2015) at 190° C.; and
a chemical composition distribution broadness (CCDB) of ≥15.0,
wherein the CCDB is determined according to formula I:

OG Complex Work Unit Math
wherein
Tn−2 is the moment calculated according to the formula II:

OG Complex Work Unit Math
and
Tz+2 is the moment calculated according to the formula III:

OG Complex Work Unit Math
wherein
w(i) is the sampled weight fraction in wt % with regard to the total sample weight in a-TREF analysis of a sample (i) taken at temperature T(i), where T(i) >30° C., the area under the a-TREF curve being normalised to surface area=1 for T (i) >30° C.; and
T (i) is the temperature at which sample (i) is taken in a-TREF analysis, in ° C.