Polyolefin film and process for preparing the same

Patent metadata

Field	Value
Publication number	US-12404378-B2
Application number	US-202017779211-A
Country	US
Kind code	B2
Filing date	Nov 20, 2020
Priority date	Nov 28, 2019
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

The present invention relates to a polyolefin film and to a process for preparing the same. The polyolefin film, specifically, the linear low-density polyethylene film according to an embodiment of the present invention is readily formed and has excellent mechanical strength and excellent heat seal characteristics.

First claim

The invention claimed is:

1. A polyolefin film, which is molded from a polyolefin having (1) a density of 0.910 to 0.940 g/cm 3 ; (2) a melt flow ratio (MFR) of 10 to 60 when measured at 190° C. as a ratio of the melt index (121.6) under a load of 21.6 kg to the melt index (12.16) under a load of 2.16 kg; and (3) a comonomer distribution slope (CDS) of 1 or more as defined by Equation 1, wherein the film has a heat seal strength of 90 gf/2.5 cm or more when measured at 0.2 bar, 1.5 seconds, and 125° C., and a heat seal strength of 210 gf/2.5 cm or more when measured at 0.2 bar, 1.5 seconds, and 140° C.:

C
⁢
D
⁢
S

=

log
⁢

C

8
⁢
0

-

log
⁢

C

2
⁢
0

log
⁢

M

8
⁢
0

-

log
⁢

M

2
⁢
0

[

Equation
⁢

1

]

in the equation, C 20 and C 80 are the comonomer contents at the point where the cumulative weight fraction in the comonomer distribution is 20% and 80%, respectively, and M 20 and M 80 are the molecular weights at which the cumulative weight fraction in the comonomer distribution is 20% and 80%, respectively, and
wherein the polyolefin is a copolymer of an olefinic monomer and an olefinic comonomer.

2. The polyolefin film of claim 1 , wherein the polyolefin has (1) a density of 0.910 to 0.920 g/cm 3 ; (2) an MFR of 20 to 40; and (3) a CDS of 2 to 5.

3. The polyolefin film of claim 1 , wherein the polyolefin is prepared by polymerizing an olefinic monomer in the presence of a catalyst comprising at least one transition metal compound represented by Formula 1 and at least one cocatalyst compound:

in Formula 1, n is each independently an integer of 1 to 20,
M is titanium (Ti), zirconium (Zr), or hafnium (Hf),
X is each independently halogen, C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 6-20 aryl, C 1-20 alkyl C 6-20 aryl, C 6-20 aryl C 1-20 alkyl, C 1-20 alkylamido, C 6-20 arylamido, or C 1-20 alkylidene,
R 1 to R 4 and R 5 to R 8 are each independently hydrogen, substituted or unsubstituted C 1-20 alkyl, substituted or unsubstituted C 2-20 alkenyl, substituted or unsubstituted C 6-20 aryl, substituted or unsubstituted C 1-20 alkyl C 6-20 aryl, substituted or unsubstituted C 6-20 aryl C 1-20 alkyl, substituted or unsubstituted C 1-20 heteroalkyl, substituted or unsubstituted C 3-20 heteroaryl, substituted or unsubstituted C 1-20 alkylamido, substituted or unsubstituted C 6-20 arylamido, substituted or unsubstituted C 1-20 alkylidene, or substituted or unsubstituted C 1-20 silyl,
R 9 to R 11 and R 12 to R 14 are each independently substituted or unsubstituted C 1-20 alkyl, substituted or unsubstituted C 2-20 alkenyl, substituted or unsubstituted C 6-20 aryl, substituted or unsubstituted C 1-20 alkyl C 6-20 aryl, substituted or unsubstituted C 6-20 aryl C 1-20 alkyl, substituted or unsubstituted C 1-20 heteroalkyl, substituted or unsubstituted C 3-20 heteroaryl, substituted or unsubstituted C 1-20 alkylamido, substituted or unsubstituted C 6-20 arylamido, substituted or unsubstituted C 1-20 alkylidene, or substituted or unsubstituted C 1-20 silyl, and
R 1 to R 4 and R 5 to R 8 are each independently capable of being linked to adjacent groups to form a substituted or unsubstituted saturated or unsaturated C 4-20 ring.

4. The polyolefin film of claim 3 , wherein the cocatalyst compound is at least one selected from the group consisting of a compound represented by Formula 2, a compound represented by Formula 3, and a compound represented by Formula 4:
[L-H] + [Z(A) 4 ] − or [L] + [Z(A) 4 ] −   [Formula 4]

in Formula 2, n is an integer of 2 or more, and Ra may each independently be a halogen atom, C 1-20 hydrocarbon, or C 1-20 hydrocarbon substituted with halogen,
in Formula 3, D is aluminum (Al) or boron, and R b , R c , and R d are each independently a halogen atom, C 1-20 hydrocarbon, C 1-20 hydrocarbon substituted with halogen, or C 1-20 alkoxy, and
in Formula 4, L is a neutral or cationic Lewis acid, [L-H] + and [L] + a Bronsted acid, Z is a group 13 element, and A is each independently substituted or unsubstituted C 6-20 aryl or substituted or unsubstituted C 1-20 alkyl.

5. The polyolefin film of claim 3 , which further comprises a carrier for supporting the transition metal compound and the cocatalyst compound.

6. The polyolefin film of claim 1 , wherein the olefinic monomer is ethylene, and the olefinic comonomer is at least one selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, and 1-hexadecene.

7. The polyolefin film of claim 6 , wherein the polyolefin is a linear low-density polyethylene in which the olefinic monomer is ethylene, and the olefinic comonomer is 1-hexene.

8. The polyolefin film of claim 1 , which has a hot tack strength at 95° C. of 0.5 N/2 cm or more and a hot tack strength at 110° C. of 3.5 N/2 cm or more.

9. The polyolefin film of claim 1 , which has a haze of 10% or less when measured based on a thickness of 50 μm.

10. The polyolefin film of claim 1 , which is at least one selected from the group consisting of a stretch film, an overlap film, a lamination, a silage wrap, and an agricultural film.

11. A process for preparing a polyolefin film, which comprises (a) polymerizing an olefinic monomer in the presence of a catalyst comprising

Assignees

• Hanwha Solutions Corp

Inventors

• Joung Ui Gap
• Kim Sung Dong
• Park Hye Ran
• Seo Junho
• Lee Munhee
• Lim Seongjae
• Jeong Yujeong
• Jeong Tae Uk

Classifications

• C08J2323/06

  Polyethene · CPC title

• C08F10/02

  Ethene · CPC title

• C08F4/6592

  containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title

• C08J2323/08

  Copolymers of ethene (C08J2323/16 takes precedence) · CPC title