Polyolefin and Film Comprising the Same

Patent metadata

Field	Value
Publication number	US-2025215121-A1
Application number	US-202318852788-A
Country	US
Kind code	A1
Filing date	Oct 20, 2023
Priority date	Nov 2, 2022
Publication date	Jul 3, 2025
Grant date	—

Abstract

Provided are a polyolefin exhibiting excellent haze property along with high drop impact strength property, and a film including the same, wherein the polyolefin has a molecular weight distribution of 2.5 to 4, a difficulty of crystallization (F(T)) and a ratio (a) of Avrami parameter to Ozawa parameter, calculated according to the Mo method after differential scanning calorimetry, satisfy the following (i) and (ii) under 20% relative crystallinity, anda peak height ratio of AH/A1 satisfies the following (iii) in a temperature rising elution fractionation curve by cross fraction chromatography analysis:(i) F(T)≤15(ii) a>1.45(iii) AH/A1≥1.8.

First claim

1 . A polyolefin having
a molecular weight distribution of 2.5 to 4, a difficulty of crystallization (F(T)) and a ratio (a) of Avrami parameter to Ozawa parameter, calculated according to Mo method after a differential scanning calorimetry, satisfying the following (i) and (ii) under 20% relative crystallinity, and a peak height ratio of A H /A 1 satisfying the following (iii) in a temperature rising elution fractionation curve by a cross fraction chromatography analysis:

F
⁡
(
T
)

≤
15

(
i
)

a
>
1.45

(
ii
)

A
H

/

A
1

≥

1
.
8

(
iii
)

in (iii),
A H represents a peak height of a highest peak in the temperature rising elution fractionation curve, and
A 1 represents a peak height of a lowest peak when the lowest peak in the temperature rising elution fractionation curve exists at an elution temperature of 40° C. to 75° C., and represents a height at an elution temperature of 65° C. when the lowest peak in the temperature rising elution fractionation curve does not exist at an elution temperature of 40° C. to 75° C., or when the lowest peak does not exist because the temperature rising elution fractionation curve has a single peak.

2 . The polyolefin of claim 1 , wherein F(T) and a are obtained by a method comprising:
a step of differential scanning calorimetry analysis, wherein the polyolefin is introduced into a differential scanning calorimeter, cooled to 20° C. at a cooling rate of N° C./min (where N=5, 10, 15, and 20), and maintained at 20° C. for 5 minutes, and then the cooled polyolefin is heated again to 160° C. at a rate of 10° C./min to measure changes in a melting enthalpy; a step of calculating a crystallization completion time, which is the time taken to reach a temperature corresponding to the 20% relative crystallinity when cooled from 120° C. at a cooling rate of N° C./min (where N=5, 10, 15, or 20), wherein the 20% relative crystallinity is determined by a point where an enthalpy value is 20%, when crystallization peaks between 30° C. and 120° C. in a differential temperature curve obtained as a result of the differential scanning calorimetry analysis are set as an analysis area, and a total enthalpy value of a corresponding area is regarded as 100% relative crystallinity; a step of obtaining a first-order linear relationship by plotting logarithm of the crystallization completion time (log t) calculated above on a X-axis and logarithm of the cooling rate (log (D) on a Y axis, and then curve fitting; and a step of determining a y-intercept and a slope in the first-order linear relationship as F(T) and a, respectively.

3 . The polyolefin of claim 1 , wherein F(T) is 10 to 15, and a is 1.46 to 1.6.

4 . The polyolefin of claim 1 , wherein A H /A 1 is 1.8 to 3.

5 . The polyolefin of claim 1 , which has a M L of 130,000 g/mol or more, which is a weight average molecular weight of a polymer eluted in a region of an elution temperature of 35° C. to 75° C. in the temperature rising elution fractionation curve by the cross fraction chromatography analysis, and a content ratio W L of 533% by weight to 45% by weight or more, based on a total weight of all eluted fractions, and
a M H of 70,000 g/mol to 110,000 g/mol, which is a weight average molecular weight of a polymer eluted in a region of an elution temperature of higher than 75° C., and a content ratio W H of 50% by weight to 60% by weight, based on the total weight of all eluted fractions.

6 . The polyolefin of claim 1 , which has a Te L of 60° C. to 90° C., which is an elution temperature of the lowest peak, and a Te H of 80° C. to 100° C., which is an elution temperature of the highest peak, in the temperature rising elution fractionation curve by the cross fraction chromatography analysis.

7 . The polyolefin of claim 1 , which has a density of 0.915 g/cc to 0.925 g/cc, as measured according to ASTM D1505.

8 . The polyolefin of claim 1 , which has a MI 2.16 of 0.5 g/10 min to 1.5 g/10 min, which is a melt index measured according to ASTM D 1238 at a temperature of 190° C. under a load of 2.16 kg, and a MI 21.6 of 10 g/10 min to 50 g/10 min, which is a melt index measured at a temperature of 190° C. under a load of 21.6 kg.

9 . The polyolefin of claim 1 , which has a MFRR of 20 to 30, which is a ratio obtained by dividing a melt index of MI 21.6 measured according to ASTM D1238 standard at a temperature of 190° C. under a load of 21.6 kg by a melt index of MI 2.16 measured at a temperature of 190° C. under a load of 2.16 kg.

10 . The polyolefin of claim 1 , which is a copolymer of ethylene/1-hexene.

11 . A film comprising the polyolefin of claim 1 .

12 . The film of claim 11 , which has a dart drop impact strength of 1600 gf or more, as measured according to Method A of ASTM D 1709 under conditions of BUR of 2.3 to 3 and a film thickness of 50 μm to 65 μm, and has a haze of 15% or less, as measured according to ISO 13468 standard.

13 . The film of claim 11 , which is a blown film.

Assignees

• Lg Chemical Ltd

Inventors

• Hong Seok Bin
• Kim Hyun Tae
• Choi Sungho
• Jeon Sangjin
• Lee Jinyoung
• Gwon Donghyeon
• Lee Chaeeun

Classifications

• C08F2420/10

  Heteroatom-substituted bridge, i.e. Cp or analog where the bridge linking the two Cps or analogs is substituted by at least one group that contains a heteroatom · CPC title

• C08J2323/08

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

• C08F210/16

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08F10/14 Primary

  Monomers containing five or more carbon atoms · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title