U.S. patent application number 16/076131 was filed with the patent office on 2020-08-20 for ethylene-based polymers and processes to make the same.
This patent application is currently assigned to Dow Global Technologies LLC. The applicant listed for this patent is DOW GLOBAL TECHNOLOGIES LLC. Invention is credited to Hayley A. BROWN, David T. GILLESPIE, Lori L. KARDOS, Teresa P. KARJALA, Jose ORTEGA, Zachary L. POLK.
Application Number | 20200263008 16/076131 |
Document ID | 20200263008 / US20200263008 |
Family ID | 1000004840574 |
Filed Date | 2020-08-20 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200263008 |
Kind Code |
A1 |
KARJALA; Teresa P. ; et
al. |
August 20, 2020 |
ETHYLENE-BASED POLYMERS AND PROCESSES TO MAKE THE SAME
Abstract
The invention provides a composition comprising an
ethylene-based polymer, wherein the ethylene-based polymer
comprises the following properties: a) a Mw(abs)/Mw(conv)>2.60;
and b) a CDFR.sub.IR (at Mw<10,000 g/mole)>0.145.
Inventors: |
KARJALA; Teresa P.; (Lake
Jackson, TX) ; KARDOS; Lori L.; (Sugar Land, TX)
; BROWN; Hayley A.; (Houston, TX) ; GILLESPIE;
David T.; (Pearland, TX) ; POLK; Zachary L.;
(Pearland, TX) ; ORTEGA; Jose; (Lake Jackson,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DOW GLOBAL TECHNOLOGIES LLC |
Midland |
MI |
US |
|
|
Assignee: |
Dow Global Technologies LLC
Midland
MI
|
Family ID: |
1000004840574 |
Appl. No.: |
16/076131 |
Filed: |
February 16, 2017 |
PCT Filed: |
February 16, 2017 |
PCT NO: |
PCT/US2017/018091 |
371 Date: |
August 7, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62298741 |
Feb 23, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 2500/12 20130101;
C08L 23/06 20130101; C08F 110/02 20130101; C08L 2207/066 20130101;
C08F 10/02 20130101 |
International
Class: |
C08L 23/06 20060101
C08L023/06 |
Claims
1-10. (canceled)
11. A composition comprising an ethylene-based polymer, wherein the
ethylene-based polymer comprises the following properties: a) a
Mw(abs)/Mw(conv).gtoreq.2.60; and b) a CDF.sub.IR (at
MW.ltoreq.10,000 g/mole).gtoreq.0.145, wherein Mw(abs) is weight
average molecular weight determined by Gel Permeation
Chromatography (GPC) using a low angle laser light scattering
(LALLS) detector; Mw(conv) is weight average molecular weight
determined by conventional GPC molecular weight calibration; and
CDF.sub.IR (at MW.ltoreq.10,000 g/mole) is an infrared cumulative
detector fraction computed by measuring an area fraction of a GPC
IRS measurement channel (IR) detector chromatogram at less than
10,000 g/mol.
12. The composition of claim 11, wherein the ethylene-based polymer
has a CDF.sub.DV (at a MW.gtoreq.1.2.times.10.sup.6
g/mol).gtoreq.0.05, wherein CDF.sub.DV (at a
MW.gtoreq.1.2.times.10.sup.6 g/mol) is a cumulative detector
fraction from the viscosity detector computed by measuring an area
fraction of a GPC viscosity chromatogram at greater than
1.2.times.10.sup.6 g/mol.
13. The composition of claim 11, wherein the ethylene-based polymer
has an IV (intrinsic viscosity) (units=dl/g).gtoreq.1.00 dl/g,
intrinsic viscosity (Absolute by viscometer on-line by GPC) or IV
(bulk).
14. The composition of claim 11, wherein the ethylene-based polymer
has an Mw(abs) from 400,000 g/mol to 600,000 g/mol.
15. The composition of claim 11, wherein the ethylene-based polymer
has a CDF.sub.LS (at MW.gtoreq.750,000 g/mol).gtoreq.0.45, wherein
the CDF.sub.LS is computed by measuring the area fraction of a GPC
LALLS detector chromatogram at greater than 750,000 g/mol.
16. The composition of claim 11, wherein the ethylene-based polymer
has a "peak melt strength at 190.degree. C." greater than
"-65*(I.sub.2 at 190.degree. C.)+34 cN" and less than "-65*(I.sub.2
at 190.degree. C.)+43 cN", wherein I.sub.2 is measured according to
ASTM D1238 at 190.degree. C. and a 2.16 kg load.
17. The composition of claim 11, wherein the ethylene-based polymer
has Mw(conv)/Mn(conv) (cc-GPC Mw/Mn) from 9 to 13, wherein Mn(conv)
is number average molecular weight determined by conventional GPC
molecular weight calibration.
18. The composition of claim 11, wherein the ethylene-based polymer
has a melt index (I.sub.2) from 0.01 to 1.00 g/10 min when measured
according to ASTM D1238 at 190.degree. C. and a 2.16 kg load.
19. The composition of claim 11, wherein the ethylene-based polymer
is a low density polyethylene (LDPE).
20. An article comprising at least one component formed from the
composition of claim 11.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Application 62/298741, filed Feb. 23, 2016.
BACKGROUND OF THE INVENTION
[0002] Blown film production lines are typically limited in output
by bubble stability. Blending Linear Low Density Polyethylene
(LLDPE) with 0.5 wt %-90 wt % of Low Density Polyethylene (LDPE)
increases bubble stability, in part due to the higher melt strength
of the LDPE. The increase in melt strength, in part, provides for
an increase in film output. High melt strength resins also
typically have reduced optics and toughness properties. Thus, there
is a need for new ethylene-based polymers, such as LDPEs, that have
an optimized balance of melt strength and film properties, such as
shrink, for blown film applications. LDPE polymers are disclosed in
the following references: WO 2010/042390, WO 2010/144784, WO
2011/019563, WO 2012/082393, WO 2006/049783, WO 2009/114661, WO
2014/190039, WO 2014/190041, WO 2014/190036, WO 2014/179469, WO
2015/094566, US 2008/0125553, US 2014/0316096, US 2014/0316094, US
2014/0288257, US 2015/0274856, US 7741415, U.S. Pat. No. 8871876,
U.S. Pat. No. 8415422, U.S. Pat. No. 8871887, U.S. Pat. No.
8916667, U.S. Pat. No. 9243087, U.S. Pat. No. 9068032 and EP
2239283B1. However, such polymers do not provide an optimized
balance of high melt strength, improved blown film maximum output,
and excellent film properties. Thus, as discussed above, there
remains a need for new ethylene-based polymers, such as LDPEs, that
have an optimized balance of melt strength, output and film
properties. These needs and others have been met by the following
invention.
SUMMARY OF THE INVENTION
[0003] The invention provides a composition comprising an
ethylene-based polymer, which comprises the following properties:
[0004] a) a Mw(abs)/Mw(conv).gtoreq.2.60; and [0005] b) a
CDF.sub.IR(at MW.ltoreq.10,000 g/mole).gtoreq.0.145.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 depicts a chromatogram for the CDF.sub.IR
determination of Example 1. FIG. 2 depicts a chromatogram for the
CDF.sub.LS determination of Example 1. FIG. 3 depicts a
chromatogram for the CDF.sub.DV determination of Example 1. FIG. 4
depicts a block diagram of the polymerization system used to
produce the ethylene-based polymers (LDPE) of Examples 1-4. FIG. 5
depicts the "peak melt strength as a function of melt index" for
the inventive examples and comparative examples.
DETAILED DESCRIPTION
[0007] Novel ethylene-based polymers, such as LDPEs, were developed
with an optimized balance of high melt strength, improved blown
film maximum output, and excellent film properties. The high melt
strength allows an increase in the processability and output of the
inventive polymers and blends containing the same.
[0008] As discussed above, the invention provides a composition
comprising an ethylene-based polymer, which comprises the following
properties: [0009] a) a Mw(abs)/Mw(conv).gtoreq.2.60; and [0010] b)
a CDF.sub.IR (at MW .ltoreq.10,000 g/mole).gtoreq.0.145.
[0011] The composition may comprise a combination of two or more
embodiments as described herein. The ethylene-based polymer may
comprise a combination of two or more embodiments as described
herein.
[0012] In one embodiment, the ethylene-based polymer has a
CDF.sub.IR (at MW.ltoreq.10,000 g/mole).gtoreq.0.140, or
.gtoreq.0.142, or .gtoreq.0.145, or .gtoreq.0.148, or
.gtoreq.0.150, or .gtoreq.0.153, or .gtoreq.0.155, or
.gtoreq.0.160, or .gtoreq.0.165. In a further embodiment, the
ethylene-based polymer is a LDPE. A LDPE is known in the art, and
refers to an ethylene homopolymer prepared using a free-radical,
high pressure (.gtoreq.100 MPa (for example, 100-400 MPa))
polymerization. In one embodiment, the ethylene-based polymer has a
CDF.sub.IR (at MW.ltoreq.10,000 g/mole).ltoreq.0.250, or
.ltoreq.0.245, or .ltoreq.0.240, or .ltoreq.0.235, or
.ltoreq.0.230, or .ltoreq.0.225, or .ltoreq.0.220, or
.ltoreq.0.215, or .ltoreq.0.210, or .ltoreq.0.205, or
.ltoreq.0.200, or .ltoreq.0.195, or .ltoreq.0.190. In a further
embodiment, the ethylene-based polymer is a LDPE.
[0013] In one embodiment, the ethylene-based polymer has a
CDF.sub.LS (at MW.gtoreq.750,000 g/mole) .gtoreq.0.400, or
.gtoreq.0.410, or .gtoreq.0.420, or .gtoreq.0.430, or
.gtoreq.0.440, or .gtoreq.0.450, or .gtoreq.0.460, or
.gtoreq.0.470, or .gtoreq.0.480, or .gtoreq.0.490, or
.gtoreq.0.500, or .gtoreq.0.510, or .gtoreq.0.520, or
.gtoreq.0.522, or .gtoreq.0.525. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has a CDF.sub.LS (at MW.gtoreq.750,000
g/mole).ltoreq.0.700, or .ltoreq.0.690, or .ltoreq.0.680, or
.ltoreq.0.670, or .ltoreq.0.660, or .ltoreq.or 0.650, or
.ltoreq.0.640, or .ltoreq.0.630 or .ltoreq.0.620, or .ltoreq.0.610,
or .ltoreq.0.600. In a further embodiment, the ethylene-based
polymer is a LDPE.
[0014] In one embodiment, the ethylene-based polymer has a
CDF.sub.DV (at MW.gtoreq.1, 200,000 g/mole).gtoreq.0.005, or
.gtoreq.0.010, or .gtoreq.0.015, or .gtoreq.0.020, or
.gtoreq.0.025, or .gtoreq.0.030, or .gtoreq.0.035, or
.gtoreq.0.040. In a further embodiment, the ethylene-based polymer
is a LDPE. In one embodiment, the ethylene-based polymer has a
CDF.sub.DV (at MW.gtoreq.1, 200,000 g/mole).ltoreq.0.150, or
.ltoreq.0.145, or .ltoreq.0.140, or .ltoreq.0.135, or
.ltoreq.0.130, or .ltoreq.0.125. In one embodiment, the
ethylene-based polymer has a CDF.sub.DV (at MW.gtoreq.1, 200,000
g/mole).ltoreq.0.120, or .ltoreq.0.115, or .ltoreq.0.110,
.ltoreq.0.105, or .ltoreq.0.100, or .ltoreq.0.095, or
.ltoreq.0.090, or .ltoreq.0.085. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0015] In one embodiment, the ethylene-based polymer has a Mw
(Absolute by Light Scattering on-line by GPC) from 400,000 g/mol to
600,000 g/mol. In a further embodiment, the ethylene-based polymer
is a LDPE.
[0016] In one embodiment, the ethylene-based polymer has an
intrinsic viscosity (Absolute by viscometer on-line by GPC) or IV
(bulk)>1.00 dl/g, further>1.10 dl/g. In a further embodiment,
the ethylene-based polymer is a LDPE.
[0017] In one embodiment, the ethylene-based polymer has an
Mw(abs)/Mw(conv) ratio.gtoreq.2.62, or .gtoreq.2.65, or
.gtoreq.2.68, or .gtoreq.2.70. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has an Mw(abs)/Mw(conv) ratio from 2.60 to
5.00, further from 2.60 to 4.50, further from 2.60 to 4.00, further
from 2.60 to 3.50, and further from 2.60 to 3.00. In a further
embodiment, the ethylene-based polymer is a LDPE.
[0018] In one embodiment, the polymer has a GPC Mw(conv) from
75,000 g/mol to 250,000 g/mol, further from 100,000 to 200,000
g/mol, further from 125,000 g/mol to 175,000 g/mol, and further
from 150,000 to 175,000 g/mol. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0019] In one embodiment, the polymer has a
Mw(conv)/Mn(conv).gtoreq.8.5, or .gtoreq.9.0, or .gtoreq.9.5. In a
further embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the polymer has a Mw(conv)/Mn(conv).ltoreq.15.0, or
.ltoreq.14.0, or .ltoreq.13.0. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the polymer
has a Mw(conv)/Mn(conv) from 8.5 to 15.0, further from 8.5 to 12.0,
further from 10.0 to 11.0. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0020] In one embodiment, the polymer has a Mn(conv) from 10,000 to
20,000 g/mol, further from 12,500 g/mol to 17,500 g/mol, further
from 14,000 g/mol to 17,000 g/mol, and further from 15,000 g/mol to
16,000 g/mol. In a further embodiment, the ethylene-based polymer
is a LDPE.
[0021] In one embodiment, the ethylene-based polymer has a
z-average molecular weight Mz(conv).gtoreq.550,000 g/mole, or
.gtoreq.600,000 g/mole, or .gtoreq.650,000 g/mole. In a further
embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer has a z-average molecular
weight Mz(conv).ltoreq.800,000 g/mole, or .ltoreq.750,000 g/mole.
In a further embodiment, the ethylene-based polymer is a LDPE. In
one embodiment, the polymer has a Mz(conv) from 500,000 to
1,000,000 g/mol, further from 600,000 g/mol to 800,000 g/mol, and
further from 650,000 g/mol to 750,000 g/mol. In a further
embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer has an Mz(conv) from 550,000
to 800,000 g/mole, further from 600,000 to 750,000 g/mole, further
from 650,000 to 750,000 g/mole. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0022] In one embodiment, the polymer has a Mw(abs) from 325,000
g/mol to 700,000 g/mol, further from 350,000 g/mol to 600,000
g/mol, further from 400,000 g/mol to 500,000 g/mol, and further
from 425,000 g/mol to 500,000 g/mol. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the polymer
has a Mz(abs) from 4,000,000 g/mol to 7,000,000 g/mol, further from
4,500,000 g/mol to 6,500,000 g/mol, further from 4,000,000 g/mol to
6,000,000 g/mol, and further from 4,250,000 g/mol to 6,000,000
g/mol. In a further embodiment, the ethylene-based polymer is a
LDPE. In one embodiment, the ethylene-based polymer has a
Mz(abs)/Mw(abs) from 6.0 to 15.0, further from 8.0 to 14.0, further
from 10.0 to 13.0, and further from 11.0 to 12.0. In a further
embodiment, the ethylene-based polymer is a LDPE.
[0023] In one embodiment, the ethylene-based polymer has a gpcBR
value from 2.3 to 5.0, further from 2.5 to 4.5, further from 2.8 to
4.0, further from 2.8 to 3.5. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has a gpcBR value from 2.0 to 4.0, or from
2.5 to 3.5, or from 2.8 to 3.4. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has an LCBf value from 2.5 to 5.0, further
from 2.75 to 4.5, further from 3.0 to 4.3, further from 3.4 to 4.1.
In a further embodiment, the ethylene-based polymer is a LDPE.
[0024] In one embodiment, the ethylene-based polymer has a melt
viscosity at 0.1 rad/s and 190.degree. C..gtoreq.30,000 Pas,
further .gtoreq.32,000 Pas (at 190.degree. C.). In a further
embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer has a melt viscosity at 0.1
rad/s and 190.degree. C..ltoreq.50,000 Pas, further .ltoreq.45,000
Pas, further .ltoreq.41,000 Pas (at 190.degree. C.). In a further
embodiment, the ethylene-based polymer is a LDPE.
[0025] In one embodiment, the ethylene-based polymer has a melt
viscosity ratio (V0.1/V100), at 190.degree. C., .gtoreq.40, or
.gtoreq.45, or .gtoreq.50. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has a viscosity ratio (V0.1/V100, at
190.degree. C.) from 40 to 60, more preferably from 43 to 55, most
preferably from 45 to 54, most preferably from 45 to 50. In a
further embodiment, the ethylene-based polymer is a LDPE.
[0026] In one embodiment, the ethylene-based polymer has a tan
delta (measured at 0.1 rad/s at 190.degree. C.).ltoreq.2.0, further
.ltoreq.1.8, further .ltoreq.1.5, and further .ltoreq.1.4. In a
further embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer has a tan delta (measured at
0.1 rad/s at 190.degree. C.) from 0.5 to 2.0, further from 0.8 to
1.8, further from 1.0 to 1.5, and further from 1.1 to 1.4. In a
further embodiment, the ethylene-based polymer is a LDPE.
[0027] In one embodiment, the ethylene-based polymer has a peak
melt strength (MS)>20.0 cN, preferably >22.0 cN, preferably
>24.0 cN. In a further embodiment, the ethylene-based polymer is
a LDPE.
[0028] In one embodiment, the ethylene-based polymer has a peak
melt strength at 190.degree. C. of greater than -65*(I.sub.2 at
190.degree. C.)+34 cN. Here, the unit of the "65 coefficient" is as
follows: "(cN)/(g/10 min)". In one embodiment, the ethylene-based
polymer has a peak melt strength at 190.degree. C. of greater than
-65*(I.sub.2 at 190.degree. C.)+34 cN and less than -65*(I.sub.2 at
190.degree. C.)+43 cN. In a further embodiment, the ethylene-based
polymer is a LDPE.
[0029] In one embodiment, the ethylene-based polymer has a melt
index (I2) from 0.01 to 10 g/10 min, further from 0.05 to 7.0 g/10
min, further from 0.1 to 5.0 g/10 min. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has a melt index (I2) from 0.01 to 1.5 g/10
min, further from 0.05 to 1.0 g/10 min, and further from 0.05 to
0.50 g/10 min. In a further embodiment, the ethylene-based polymer
is a LDPE. In one embodiment, the ethylene-based polymer has a melt
index (I2) from 0.01 to 1.00 g/10 min, further from 0.01 to 0.70
g/10 min, further from 0.01 to 0.50 g/10 min, further from 0.01 to
0.40 g/10 min. In a further embodiment, the ethylene-based polymer
is a LDPE.
[0030] In one embodiment, the ethylene-based polymer has a melt
index (I2).ltoreq.1.0, further .ltoreq.0.5. In a further
embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer has a melt index (I2) from
0.015 to 1.0 g/10 min, further from 0.02 to 0.5 g/10 min, further
from 0.05 to 0.4 g/10 min, and further from 0.1 to 0.35 g/10 min.
In a further embodiment, the ethylene-based polymer is a LDPE. In
one embodiment, the ethylene-based polymer has a melt index (I2)
from 0.02 to 1.0 g/10 min, further from 0.05 to 0.5 g/10 min,
further from 0.1 to 0.4 g/10 min, and further from 0.15 to 0.35
g/10 min. In a further embodiment, the ethylene-based polymer is a
LDPE.
[0031] In one embodiment, the ethylene-based polymer has a density
from 0.910 to 0.940 g/cc, further from 0.910 to 0.930 g/cc, further
from 0.915 to 0.925 g/cc, further from 0.916 to 0.922 g/cc, further
from 0.918 to 0.921 g/cc, and further from 0.919 to 0.921 g/cc (1
cc=1 cm.sup.3). In a further embodiment, the ethylene-based polymer
is a LDPE.
[0032] In one embodiment, the ethylene-based polymer has a % hexane
extractables from 1.0 to 4.0 wt %, further from 1.6 to 2.6 wt %,
further from 1.8 to 2.4 wt %, and further from 1.9 to 2.2 wt %,
based on the weight of the polymer. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0033] In one embodiment, the ethylene-based polymer has
.gtoreq.0.1 amyl groups (C5) per 1000 total carbon atoms, as
determined by .sup.13C NMR. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has .gtoreq.0.2 amyl (C5) groups (branches)
per 1000 total carbon atoms, further .gtoreq.0.5 amyl groups per
1000 total carbon atoms, further .gtoreq.1 amyl groups per 1000
total carbon atoms, further .gtoreq.1.5 amyl groups per 1000 total
carbon atoms, further .gtoreq.1.75 amyl groups per 1000 total
carbon atoms, and further .gtoreq.2.0 amyl groups per 1000 total
carbon atoms, in which the amyl group is equivalent to the C5 group
and is measured by .sup.13C NMR. In a further embodiment, the
ethylene-based polymer is a LDPE.
[0034] In one embodiment, the ethylene-based polymer has from 0.1
to 1.5 C1 (methyl groups) per 1000 total carbon atoms, further from
0.2 to 1.0 C1 (methyl) per 1000 total carbon atoms, and further
from 0.3 to 0.5 C1 (methyl) per 1000 total carbon atoms, as
determined by .sup.13C NMR. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has from 4.0 to 6.0 of 1,3 diethyl branches
per 1000 total carbon atoms, further from 4.1 to 5.0 of 1,3 diethyl
branches per 1000 total carbon atoms, and further from 4.2 to 4.7
of 1,3 diethyl branches per 1000 total carbon atoms, as determined
by .sup.13C NMR. In a further embodiment, the ethylene-based
polymer is a LDPE.
[0035] In one embodiment, the ethylene-based polymer has from 1.0
to 3.0 C2 on the quaternary carbon atom per 1000 total carbon
atoms, further from 1.4 to 2.0 C2 on the quaternary carbon atom per
1000 total carbon atoms, and further from 1.45 to 1.7 C2 on the
quaternary carbon atom per 1000 total carbon atoms, as determined
by .sup.13C NMR. In a further embodiment, the ethylene-based
polymer is a LDPE.
[0036] In one embodiment, the ethylene-based polymer has from 0.04
to 0.09 vinyls per 1000 total carbon atoms, further from 0.04 to
0.08 vinyls per 1000 total carbon atoms, and further from 0.05 to
0.08 vinyls per 1000 total carbon atoms, as determined by 1H NMR.
In a further embodiment, the ethylene-based polymer is a LDPE. In
one embodiment, the ethylene-based polymer has from 0.03 to 0.06
cis and trans groups (vinylene) per 1000 total carbon atoms, and
further from 0.03 to 0.05 cis and trans per 1000 total carbon
atoms, as determined by 1H NMR. In a further embodiment, the
ethylene-based polymer is a LDPE. In one embodiment, the
ethylene-based polymer has from 0.1 to 0.4 vinylidene per 1000
total carbon atoms, and further from 0.1 to 0.3 vinylidene per 1000
total carbon atoms, as determined by 1H NMR. In a further
embodiment, the ethylene-based polymer is a LDPE.
[0037] In one embodiment, the ethylene-based polymer has a
crystallization temperature from 98.5.degree. C. to 100.0.degree.
C., and further from 98.7.degree. C. to 99.5.degree. C. In a
further embodiment, the ethylene-based polymer is a LDPE.
[0038] In one embodiment, the ethylene-based polymer is formed in a
high pressure (P greater than 100 MPa), free radical polymerization
process. In a further embodiment, the ethylene-based polymer is a
LDPE. In one embodiment, the ethylene-based polymer is formed in at
least one tubular reactor.
[0039] In one embodiment, the ethylene-based polymer is a low
density polyethylene (LDPE).
[0040] In one embodiment, the ethylene-based polymer is present at
greater than, or equal to, 10 weight percent, based on the weight
of the composition. In a further embodiment, the ethylene-based
polymer is a LDPE. In one embodiment, the ethylene-based polymer is
present in an amount from 10 to 50 weight percent, further from 20
to 40 weight percent, based on the weight of the composition. In a
further embodiment, the ethylene-based polymer is a LDPE. In one
embodiment, the ethylene-based polymer is present in an amount from
60 to 90 weight percent, further from 65 to 85 weight percent,
based on the weight of the composition. In a further embodiment,
the ethylene-based polymer is a LDPE.
[0041] In one embodiment, the ethylene-based polymer is present in
an amount from 1 to 10 weight percent, further from 1.5 to 5 weight
percent, based on the weight of the composition. In a further
embodiment, the ethylene-based polymer is a LDPE.
[0042] In one embodiment, the composition further comprises another
ethylene-based polymer. Suitable other ethylene-based polymers
include, but are not limited to, DOWLEX Polyethylene Resins, TUFLIN
Linear Low Density Polyethylene Resins, ELITE or ELITE AT Enhanced
Polyethylene Resins, or INNATE Precision Packaging Resins (all
available from The Dow Chemical Company), high density
polyethylenes (d.gtoreq.0.96 g/cc), medium density polyethylenes
(density from 0.935 to 0.955 g/cc), EXCEED polymers and ENABLE
polymers (both from ExxonMobil), LDPE, and EVA (ethylene vinyl
acetate).
[0043] In one embodiment, the composition further comprises another
ethylene-based polymer that differs in one or more properties, such
as density, melt index, comonomer, comonomer content, from the
inventive ethylene-based polymer. Suitable other ethylene-based
polymers include, but are not limited to, DOWLEX Polyethylene
Resins (LLDPEs), TUFLIN Linear Low Density Polyethylene Resins,
ELITE or ELITE AT Enhanced Polyethylene Resins, or INNATE Precision
Packaging Resins (all available from The Dow Chemical Company),
high density polyethylenes (d.gtoreq.0.96 g/cc), medium density
polyethylenes (density from 0.935 to 0.955 g/cc), EXCEED polymers
and ENABLE polymers (both from ExxonMobil), LDPE, and EVA (ethylene
vinyl acetate).
[0044] In one embodiment, the composition further comprises a
propylene-based polymer. Suitable propylene-based polymers include
polypropylene homopolymers, propylene/.alpha.-olefin interpolymers,
and propylene/ethylene interpolymers. In one embodiment, the
composition further comprises a heterogeneously branched
ethylene/.alpha.-olefin interpolymer, and preferably a
heterogeneously branched ethylene/.alpha.-olefin copolymer. In one
embodiment, the heterogeneously branched ethylene/.alpha.-olefin
interpolymer, and preferably a heterogeneously branched
ethylene/.alpha.-olefin copolymer, has a density from 0.89 to 0.94
g/cc, further from 0.90 to 0.93 g/cc. In a further embodiment, the
composition comprises 1 to 99 weight percent, further from 15 to 85
weight percent, of the inventive ethylene-based polymer, based on
the weight of the composition. In one embodiment, the composition
comprises <1.0 wt %, or <0.5 wt %, or <0.2 wt %, or
<0.1 wt %, or <0.05 wt %, or <0.02 wt %, or <0.01 wt %
of a propylene-based polymer, based on the weight of the
composition.
[0045] In one embodiment, the composition comprises <5 ppm,
further <2 ppm, further <1 ppm, and further <0.5 ppm
sulfur, based on the weight of the composition. In one embodiment,
the composition does not contain sulfur.
[0046] In one embodiment, the composition comprises from 1.5 to 80
weight percent of an inventive ethylene-based polymer. In a further
embodiment, the composition further comprises a LLDPE (Linear Low
Density Polyethylene). In one embodiment, the composition comprises
from 1.5 to 20 weight percent of an inventive ethylene-based
polymer. In a further embodiment, the composition further comprises
a LLDPE. In one embodiment, the composition comprises from 20 to 80
weight percent, further from 50 to 80 weight percent of an
inventive ethylene-based polymer, based on the weight of the
composition. In a further embodiment, the composition further
comprises a LLDPE.
[0047] An inventive composition may comprise a combination of two
or more embodiments as described herein.
[0048] The invention also provides an article comprising at least
one component formed from an inventive composition. In a further
embodiment, the article is a film. In another embodiment, the
article is a coating.
[0049] The invention also provides a process for forming a polymer
of any of the previous embodiments, the process comprising
polymerizing a mixture comprising ethylene, in at least one tubular
reactor. The invention also provides a process for forming an
inventive ethylene-based polymer of any of the previous
embodiments, the process comprising polymerizing a mixture
comprising ethylene, in a combination of at least one tubular
reactor and at least one autoclave reactor.
[0050] An inventive composition may comprise a combination of two
or more embodiments as described herein. An inventive
ethylene-based polymer may comprise a combination of two or more
embodiments as described herein. An inventive LDPE may comprise a
combination of two or more embodiments as described herein.
[0051] An inventive article may comprise a combination of two or
more embodiments as described herein. An inventive film may
comprise a combination of two or more embodiments as described
herein. An inventive process may comprise a combination of two or
more embodiments as described herein.
Process
[0052] For producing an inventive ethylene-based polymer, including
an inventive LDPE, a high pressure, free-radical initiated
polymerization process is typically used. Typically, a jacketed
tube is used as a reactor, which has one or more reaction zones.
Suitable, but not limiting, reactor lengths may be from 100 to 3000
meters (m), or from 1000 to 2000 meters. The beginning of a
reaction zone for the reactor is typically defined by the side
injection of initiator of the reaction, ethylene, chain transfer
agent (or telomer), as well as any combination thereof. A high
pressure process can be carried out in tubular reactors, having one
or more reaction zones, or in a combination of autoclave and
tubular reactors, each comprising one or more reaction zones. A
chain transfer agent can be used to control molecular weight. In a
preferred embodiment, one or more chain transfer agents (CTAs) are
added to an inventive polymerization process. Typical CTA's that
can be used include, but are not limited to, propylene, n-butane
and 1-butene. In one embodiment, the amount of CTA used in the
process is from 0.03 to 10 weight percent of the total reaction
mixture.
[0053] Ethylene used for the production of the ethylene-based
polymer may be purified ethylene, which is obtained by removing
polar components from a loop recycle stream, or by using a reaction
system configuration, such that only fresh ethylene is used for
making the inventive polymer. It is not typical that only purified
ethylene is required to make the ethylene-based polymer. In such
cases ethylene from the recycle loop may be used. In one
embodiment, the ethylene-based polymer is a LDPE.
Additives and Applications
[0054] An inventive composition may comprise one or more additives.
Additives include, but are not limited to, stabilizers,
plasticizers, antistatic agents, pigments, dyes, nucleating agents,
fillers, slip agents, fire retardants, processing aids, smoke
inhibitors, viscosity control agents and anti-blocking agents. The
polymer composition may, for example, comprise less than 10 percent
(by the combined weight) of one or more additives, based on the
weight of the inventive polymer composition. In one embodiment, the
polymers of this invention are treated with one or more
stabilizers, for example, antioxidants, such as IRGANOX 1010,
IRGANOX 1076 and IRGAFOS 168 (Ciba Specialty Chemicals; Glattbrugg,
Switzerland). The polymers may be treated with one or more
stabilizers before extrusion or other melt processes.
[0055] Blends and mixtures of the inventive polymer with other
polymers may be performed. Suitable polymers for blending with the
inventive polymer include natural and synthetic polymers. Exemplary
polymers for blending include propylene-based polymers (both impact
modifying polypropylene, isotactic polypropylene, atactic
polypropylene, and random ethylene/propylene copolymers), various
types of ethylene-based polymers, including high pressure,
free-radical LDPE, LLDPE prepared with Ziegler-Natta catalysts, PE
prepared with single site catalysts, including multiple reactor PE
("in reactor" blends of Ziegler-Natta PE and single site catalyzed
PE, such as products disclosed in U.S. Pat. No. 6,545,088
(Kolthammer et al.); U.S. Pat. No. 6,538,070 (Cardwell, et al.);
U.S. Pat. No. 6,566,446 (Parikh, et al.); U.S. Pat. No. 5,844,045
(Kolthammer et al.); U.S. Pat. No. 5,869,575 (Kolthammer et al.);
and U.S. Pat. No. 6,448,341 (Kolthammer et al.)), EVA,
ethylene/vinyl alcohol copolymers, polystyrene, impact modified
polystyrene, ABS, styrene/butadiene block copolymers and
hydrogenated derivatives thereof (SBS and SEBS), and thermoplastic
polyurethanes. Homogeneous polymers, such as olefin plastomers and
elastomers, ethylene and propylene-based copolymers (for example,
polymers available under the trade designation VERSIFY Plastomers
& Elastomers (The Dow Chemical Company) and VISTAMAXX
(ExxonMobil Chemical Co.) can also be useful as components in
blends comprising the inventive polymer).
[0056] The polymers of this invention may be employed in a variety
of conventional thermoplastic fabrication processes to produce
useful articles, including, but not limited to, monolayer and
multilayer films; molded articles, such as blow molded, injection
molded, or rotomolded articles; coatings (for example, extrusion
coatings); fibers; and woven or non-woven fabrics. An inventive
polymer may be used in a variety of films, including but not
limited to, food packaging, consumer, industrial, agricultural
(applications or films), lamination films, fresh cut produce films,
meat films, cheese films, candy films, clarity shrink films,
collation shrink films, stretch films, silage films, greenhouse
films, fumigation films, liner films, stretch hood, heavy duty
shipping sacks, pet food, sandwich bags, sealants, and diaper
backsheets.
[0057] An inventive polymer is also useful in other direct end-use
applications. An inventive polymer may be used for wire and cable
coating operations, in sheet extrusion for vacuum forming
operations, and forming molded articles, including the use of
injection molding, blow molding process, or rotomolding processes.
Other suitable applications for the inventive polymers include
elastic films and fibers; soft touch goods, such as appliance
handles; gaskets and profiles; auto interior parts and profiles;
foam goods (both open and closed cell); impact modifiers for other
thermoplastic polymers, such as high density polyethylene, or other
olefin polymers; cap liners; and flooring.
DEFINITIONS
[0058] The term "polymer," as used herein, refers to a polymeric
compound prepared by polymerizing monomers, whether of the same or
a different type. The generic term polymer thus embraces the term
homopolymer (employed to refer to polymers prepared from only one
type of monomer, with the understanding that low amounts of
impurities (for example, low amounts (e.g., .ltoreq.1.0 wt %,
further .ltoreq.0.5 wt %, further .ltoreq.0.3 wt %) of CTA) can be
incorporated into the polymer structure), and the term interpolymer
as defined hereinafter. Impurities may be incorporated into and/or
within a polymer. The term "interpolymer," as used herein, refers
to polymers prepared by the polymerization of at least two
different types of monomers. The generic term interpolymer includes
copolymers (employed to refer to polymers prepared from two
different types of monomers), and polymers prepared from more than
two different types of monomers.
[0059] The term "ethylene-based polymer," as used herein, refers to
a polymer that comprises a majority amount of polymerized ethylene
monomer (based on weight of the polymer), and, optionally, may
contain at least one comonomer. The term "propylene-based polymer,"
as used herein, refers to a polymer that comprises a majority
amount of polymerized propylene monomer (based on weight of the
polymer) and, optionally, may comprise at least one comonomer.
[0060] The term "composition," as used herein, includes a mixture
of materials which comprise the composition, as well as reaction
products and decomposition products formed from the materials of
the composition.
[0061] The terms "blend" or "polymer blend," as used, refers to a
mixture of two or more polymers. A blend may or may not be miscible
(not phase separated at the molecular level). A blend may or may
not be phase separated. A blend may or may not contain one or more
domain configurations, as determined from transmission electron
spectroscopy, light scattering, x-ray scattering, and other methods
known in the art. The blend may be effected by physically mixing
the two or more polymers on the macro level (for example, melt
blending resins or compounding) or the micro level (for example,
simultaneous forming within the same reactor).
[0062] The terms "comprising," "including," "having," and their
derivatives, are not intended to exclude the presence of any
additional component, step or procedure, whether or not the same is
specifically disclosed. In order to avoid any doubt, all
compositions claimed through use of the term "comprising" may
include any additional additive, adjuvant, or compound, whether
polymeric or otherwise, unless stated to the contrary. The term,
"consisting essentially of" excludes from the scope of any
succeeding recitation any other component, step or procedure,
excepting those that are not essential to operability. The term
"consisting of" excludes any component, step or procedure not
specifically delineated or listed.
TEST METHODS
Density
[0063] Samples for density measurements were prepared according to
ASTM D 4703-10 Annex Al Procedure C. Approximately 7 g of sample
was placed in a "2''.times.2''.times.135 mil thick" mold, and this
was pressed at 374.degree. F. (190.degree. C.) for six minutes at
3,000 lb.sub.f. Then the pressure was increased to 30,000 lb.sub.f
for four minutes. This was followed by cooling at 15.degree. C. per
minute, at 30,000 lb.sub.f, to approximately a temperature of
40.degree. C. The "2''.times.2''.times.135 mil" polymer sample
(plaque) was then removed from the mold, and three samples were cut
from the plaque with a 1/2''.times.1'' die cutter. Density
measurements were made within one hour of sample pressing, using
ASTM D792-08, Method B. Density was reported as an average of three
measurements.
Melt Index
[0064] Melt index (MI), or I2, was measured in accordance with ASTM
D 1238-10, Condition 190.degree. C./2.16 kg, Procedure B, and was
reported in grams eluted per 10 minutes (g/10 min).
Hexane Extractables
[0065] Polymer pellets (from the polymerization pelletization
process, without further modification; approximately 2.2 grams per
one "1-inch by 1-inch" square film) were pressed in a Carver Press
at a thickness of 3.0-4.0 mils. The pellets were pressed at
190.degree. C. for 3 minutes, at 40,000 lb.sub.f. Non-residue
gloves (PIP*CleanTeam*CottonLisle Inspection Gloves, Part Number:
97-501) were worn to prevent contamination of the film with
residual oils from the hands of the operator. Each film was trimmed
to a "1-inch by 1-inch" square, and weighed (2.5.+-.0.05g). The
films were extracted for two hours, in a hexane vessel, containing
about 1000 ml of hexane, at 49.5.+-.0.5.degree. C., in a heated
water bath. The hexane was an isomeric "hexanes" mixture (for
example, Hexanes (Optima), Fisher Chemical, high purity mobile
phase for HPLC and/or extraction solvent for GC applications).
After two hours, the films were removed, rinsed in clean hexane,
and dried in a vacuum oven (80.+-.5.degree. C.) at full vacuum
(ISOTEMP Vacuum Oven, Model 281A, at approximately 30 inches Hg)
for two hours. The films were then placed in a desiccator, and
allowed to cool to room temperature for a minimum of one hour. The
films were then reweighed, and the amount of mass loss due to
extraction in hexane was calculated. This method is based on 21 CRF
177.1520 (d)(3)(ii), with one deviation from FDA protocol by using
hexanes instead of n-hexane. The average of three measurements were
reported.
Nuclear Magnetic Resonance (.sup.13C NMR)
[0066] Each sample was prepared by adding approximately "3 g of a
50/50 mixture of tetrachloroethane-d2/orthodichlorobenzene,
containing 0.025 M Cr(AcAc).sub.3," to a "0.25 to 0.40 g polymer
sample," in a 10 mm NMR tube. The sample was then dissolved and
homogenized by heating the tube, and its contents to 150.degree.
C., using a heating block and heat gun. Each dissolved sample was
visually inspected to ensure homogeneity. All data were collected
using a Bruker 400 MHz spectrometer, equipped with a Bruker Dual
DUL high-temperature CryoProbe. The data was acquired using a six
second pulse repetition delay, 90-degree flip angles, and inverse
gated decoupling, with a sample temperature of 120.degree. C. All
measurements were made on non-spinning samples in locked mode. The
.sup.13C NMR chemical shifts were internally referenced to the EEE
triad at 30.0 ppm. The C6+ value was a direct measure of C6+
branches in LDPE, where the long branches were not distinguished
from chain ends. The 32.2 ppm peak, representing the third carbon
from the end of all chains or branches of six or more carbons, was
used to determine the C6+ value. Other peaks of interest are listed
in Table A.
TABLE-US-00001 TABLE A Branch Peak(s) Identity of the integrated
Type integrated carbon peak(s) 1,3 About 10.5 to 1,3 diethyl branch
methyls diethyl 11.5 ppm C1 About 19.75 to C1, methyls 20.50 ppm C2
on About 7.7 to 2 ethyl groups on a quaternary Quat 8.6 ppm carbon
Carbon C4 About 23.3 to Second CH.sub.2 in a 4-carbon branch, 23.5
ppm counting the methyl as the first C C5 About 32.60 to Third
CH.sub.2 in a 5-carbon branch, 32.80 ppm counting the methyl as the
first C
Nuclear Magnetic Resonance (.sup.1H NMR)
[0067] Each sample was prepared by adding approximately 130 mg of
sample to "3.25 g of 50/50, by weight,
tetrachlorethane-d2/perchloroethylene" with 0.001 M Cr(AcAc).sub.3,
in a NORELL 1001-7, 10 mm NMR tube. The sample was purged by
bubbling N.sub.2 through the solvent, via a pipette inserted into
the tube, for approximately five minutes, to prevent oxidation. The
tube was capped, sealed with TEFLON tape, and then soaked at room
temperature, overnight, to facilitate sample dissolution. The
sample was heated and vortexed at 115.degree. C. to ensure
homogeneity. The .sup.1H NMR was performed on a Bruker AVANCE 400
MHz spectrometer, equipped with a Bruker Dual DUL high-temperature
CryoProbe, and at a sample temperature of 120.degree. C. Two
experiments were run to obtain spectra, a control spectrum to
quantitate the total polymer protons, and a double presaturation
experiment, which suppressed the intense polymer backbone peaks,
and enabled high sensitivity spectra for quantitation of the
end-groups. The control was run with ZG pulse, 16 scans, AQ 1.64s,
D1 14s. The double presaturation experiment was run with a modified
pulse sequence, 100 scans, AQ 1.64s, presaturation delay ls,
relaxation delay 13s.
[0068] The signal from residual .sup.1H in TCE-d2 (at 6.0 ppm) was
integrated, and set to a value of 100, and the integral from 3 to
-0.5 ppm was used as the signal from the whole polymer in the
control experiment. For the presaturation experiment, the TCE
signal was also set to 100, and the corresponding integrals for
unsaturation (vinylene (cis and trans) at about 5.40 to 5.60 ppm,
trisubstituted at about 5.16 to 5.35 ppm, vinyl at about 4.95 to
5.15 ppm, and vinylidene at about 4.70 to 4.90 ppm) were
obtained.
Melt Strength
[0069] Melt strength measurements were conducted on a Gottfert
Rheotens 71.97 (Goettfert Inc.; Rock Hill, S.C.), attached to a
Gottfert Rheotester 2000 capillary rheometer. The melted sample
(about 25 to 30 grams) was fed with a Goettfert Rheotester 2000
capillary rheometer, equipped with a flat entrance angle (180
degrees) of length of 30 mm, diameter of 2.0 mm, and an aspect
ratio (length/diameter) of 15. After equilibrating the samples at
190.degree. C. for 10 minutes, the piston was run at a constant
piston speed of 0.265 mm/second. The standard test temperature was
190.degree. C. The sample was drawn uniaxially to a set of
accelerating nips, located 100 mm below the die, with an
acceleration of 2.4 mm/s.sup.2. The tensile force was recorded as a
function of the take-up speed of the nip rolls. Melt strength was
reported as the peak or maximum plateau force (cN). The following
conditions were used in the melt strength measurements: plunger
speed=0.265 mm/second; wheel acceleration=2.4 mm/s.sup.2; capillary
diameter=2.0 mm; capillary length=30 mm; and barrel diameter=12 mm.
The peak melt strength is the maximum melt strength recorded.
Dynamic Mechanical Spectroscopy (DMS)
[0070] Resins were compression-molded into "3 mm thick.times.1
inch" circular plaques at 350.degree. F., for 6.5 minutes, under
20,000 lb.sub.f, in air. The sample was then taken out of the
press, and placed on the counter to cool. A constant temperature
frequency sweep was performed, using a TA Instruments "Advanced
Rheometric Expansion System (ARES)," equipped with 25 mm (diameter)
parallel plates, under a nitrogen purge. The sample was placed on
the plate, and allowed to melt for five minutes at 190.degree. C.
The plates were then closed to a gap of 2 mm, the sample trimmed
(extra sample that extends beyond the circumference of the "25 mm
diameter" plate was removed), and then the test was started. The
method had an additional five minute delay built in, to allow for
temperature equilibrium. The experiments were performed at
190.degree. C., over a frequency range of 0.1 to 100 rad/s. The
strain amplitude was constant at 10%. The complex viscosity .eta.*,
tan (.delta.) or tan delta, viscosity at 0.1 rad/s (V0.1), the
viscosity at 100 rad/s (V100), and the viscosity ratio (V0.1/V100)
were measured.
Triple Detector Gel Permeation Chromatography (TDGPC)
[0071] The chromatographic system consisted of a PolymerChar GPC-IR
(Valencia, Spain) high temperature GPC chromatograph, equipped with
an internal IR5 infra-red detector (IR5) coupled to a Precision
Detectors (Now Agilent Technologies) 2-angle laser light scattering
(LS) detector Model 2040, and followed by a PolymerChar 4-capillary
viscosity detector (three detectors in series). For all light
scattering measurements, the 15 degree angle was used for
measurement purposes. The autosampler oven compartment was set at
160.degree. Celsius, and the column compartment was set at
150.degree. Celsius. The columns used were four, Agilent "Mixed A"
columns, each 30 cm, and each packed with 20-micron linear
mixed-bed particles. The chromatographic solvent used was
1,2,4-trichlorobenzene, which contained 200 ppm of butylated
hydroxytoluene (BHT). The solvent source was nitrogen sparged. The
injection volume was 200 microliters, and the flow rate was 1.0
milliliters/minute.
[0072] Calibration of the GPC column set was performed with 21
narrow molecular weight distribution, polystyrene standards with
molecular weights ranging from 580 to 8,400,000 g/mol. These
standards were arranged in 6 "cocktail" mixtures, with at least a
decade of separation between individual molecular weights. The
standards were purchased from Agilent Technologies. The polystyrene
standards were prepared at "0.025 grams in 50 milliliters of
solvent" for molecular weights equal to, or greater than,
1,000,000, g/mol, and at "0.05 grams in 50 milliliters of solvent"
for molecular weights less than 1,000,000 g/mol. The polystyrene
standards were dissolved at 80 degrees Celsius, with gentle
agitation, for 30 minutes. The polystyrene standard peak molecular
weights OR 5 detector) were converted to polyethylene molecular
weights using Equation 1 (as described in Williams and Ward, J.
Polym. Sci., Polym. Let., 6, 621 (1968)):
M.sub.polyethylene=A.times.(M.sub.polystyrene).sup.B (EQN 1), where
M is the molecular weight, A has a value of 0.4315, and B is equal
to 1.0. A fifth order polynomial was used to fit the respective
polyethylene-equivalent calibration points. A small adjustment to A
(from approximately 0.415 to 0.44) was made to correct for column
resolution and band-broadening effects, such that NIST standard NBS
1475 was obtained at 52,000 g/mol (Mw). The total plate count of
the GPC column set was performed with Eicosane (prepared at 0.04 g
in 50 milliliters of "TCB stabilized solvent," and dissolved for 20
minutes with gentle agitation.) The plate count (Equation 2) and
symmetry (Equation 3) were measured on a 200 microliter injection
according to the following equations:
Plate Count = 5.54 * ( ( R V Peak Max ) Peak Width at 1 2 height )
2 , ( EQN 2 ) ##EQU00001##
where RV is the retention volume in milliliters, the peak width is
in milliliters, the peak max is the maximum height of the peak, and
1/2 height is the 1/2 height of the peak maximum:
Symmetry = ( Rear Peak RV one tenth height - RV Peak max ) ( RV
Peak max - Front Peak RV one tenth height ) , ( EQN 3 )
##EQU00002##
where RV is the retention volume in milliliters, and the peak width
is in milliliters, "Peak max" is the maximum IR signal height
corresponding to an "RV position" on the chromatogram, "One tenth
height" 1/10 height of the peak maximum, where "Rear peak" refers
to the peak tail at a signal retention volume (at 1/10 height of
peak maximum), later than the peak max, and where "Front peak"
refers to the peak front at a signal retention volume (at 1/10
height of peak maximum), earlier than the peak max. The plate count
for the chromatographic system should be greater than 24,000, and
the symmetry should be between 0.98 and 1.22.
[0073] Samples were prepared in a semi-automatic manner with the
PolymerChar "Instrument Control" Software, wherein the samples were
weight-targeted at 2 mg/ml, and the solvent (contained 200 ppm BHT)
was added to a pre nitrogen-sparged septa-capped vial, via the
PolymerChar high temperature autosampler. Decane (a flow rate
marker) was added to each sample (about 5 microliters). The samples
were dissolved for two hours at 160.degree. Celsius, under a "low
speed" shaking.
IR 5 Chromatogram
[0074] The calculations of Mn(conv), Mw(conv), and Mz(conv) were
based on the GPC results, using the internal IR5 detector
(measurement channel) of the PolymerChar GPC-IR chromatograph,
according to Equations 4-6, using PolymerChar GPCOne.TM. software
(version 2013G), the baseline-subtracted IR chromatogram at each
equally-spaced data collection point (i), and the polyethylene
equivalent molecular weight obtained from the narrow standard
calibration curve for the point (i) from Equation 1. Table 4 lists
the conventional GPC results for the examples and comparative
examples using Equations 4-6, below for the conventional GPC.
Mn ( conv ) = i IR i i ( IR i / M polyethylene i ) , ( EQN 4 ) Mw (
conv ) = i ( IR i * M polyethylene i ) i IR i , ( EQN 5 ) Mz ( conv
) = i ( IR i * ( M polyethylene 2 i ) i ( IR i * M polyethylene i )
. ( EQN 6 ) ##EQU00003##
[0075] In order to monitor the deviations over time, a flowrate
marker (decane) was introduced into each sample via a micropump
controlled with the PolymerChar GPC-IR system. This flowrate marker
(FM, here decane) was used to linearly correct the pump flowrate
(Flowrate(nominal)) for each sample, by aligning the RV value of
the respective decane peak within the sample (RV(FM Sample)), to
that of the decane peak within the narrow standards calibration
(RV(FM Calibrated)). Any changes in the time of the decane marker
peak were then assumed to be related to a linear-shift in flowrate
(Flowrate(effective)) for the entire run. To facilitate the highest
accuracy of a RV measurement of the flow marker peak, a
least-squares fitting routine was used to fit the peak of the flow
marker concentration chromatogram to a quadratic equation. The
first derivative of the quadratic equation was then used to solve
for the true peak position. After calibrating the system based on a
flow marker peak, the effective flowrate (with respect to the
narrow standards calibration) was calculated using Equation 7.
Processing of the flow marker peak was done via the PolymerChar
GPCOne.TM. Software. Acceptable flowrate correction was such that
the effective flowrate should be within +/-2% of the nominal
flowrate. Flowrate(effective)=Flowrate(nominal)*(RV(FM
Calibrated)/RV(FM Sample)) (EQN 7)
[0076] The Systematic Approach for the determination of
multi-detector offsets was done in a manner consistent with that
published by Balke, Mourey, et. al. (Mourey and Balke,
Chromatography Polym. Chpt 12, (1992)) (Balke, Thitiratsakul, Lew,
Cheung, Mourey, Chromatography Polym. Chpt 13, (1992)). Alignment
of the triple detector log (MW and IV) results (generated from a
broad homopolymer polyethylene standard (Mw/Mn=3)), to the narrow
standard column calibration results (generated from the narrow
standards calibration curve), was done using the PolymerChar
GPCOne.TM. Software.
Light Scattering Chromatogram
[0077] The absolute molecular weight data (MWabs) was obtained in a
manner consistent with that published by Zimm (Zimm, B. H., J.
Chem. Phys., 16, 1099 (1948)) and Kratochvil (Kratochvil, P.,
Classical Light Scattering from Polymer Solutions, Elsevier,
Oxford, N.Y. (1987)), using the PolymerChar GPCOne.TM. software.
The overall injected concentration, used in the determination of
the molecular weight, was obtained from the mass detector area and
the mass detector constant, derived from a suitable linear
polyethylene homopolymer, or one of the polyethylene standards of
known weight-average molecular weight (traceable to NBS 1475
homopolymer polyethylene reference sample). The calculated
molecular weights (using GPCOne.TM.) were obtained using a light
scattering constant, derived from one or more of the polyethylene
standards mentioned below, and a refractive index concentration
coefficient, dn/dc, of 0.104. Generally, the mass detector response
(IR5) and the light scattering constant (determined using
GPCOne.TM.) should be determined from a linear standard with a
molecular weight in excess of about 50,000 g/mol. Table 5 lists the
light scattering GPC results for the examples and comparative
examples.
[0078] The Equation for Mw(abs) is an area-based result, using the
baseline-subtracted 15 degree light scattering signal and the
baseline-subtracted IR5 measurement sensor signal (applying the
mass and light scattering constants), as determined from GPCOne.TM.
software,
Mw ( abs ) = i LS i i IR i .times. Mass Constant / LS constant .
##EQU00004##
The equation for Mz(abs) relied on a point-by point determination
of the absolute molecular weight derived from the ratio of the
baseline-subtracted, 15 degree light scattering signal and the
baseline-subtracted, IR5 measurement sensor signal, and factored
for the mass constant and light scattering constant, using
GPCOne.TM. software. A straight-line fit was used to extrapolate
the absolute molecular weight, where either detector (IR5 or LS) is
below approximately 4% relative peak signal height (maximum peak
height).
Mz ( abs ) = i ( I R i * M Abs i 2 ) i ( I R i * M Abs i ) .
##EQU00005##
Viscosity Chromatogram
[0079] The absolute intrinsic viscosity data (IV(abs)) was obtained
using the area of the specific viscosity chromatogram, obtained
from the PolymerChar viscometer detector, when calibrated to the
known intrinsic viscosity of NBS 1475. The overall injected
concentration, used in the determination of the intrinsic
viscosity, was obtained from the mass detector area and the mass
detector constant, derived from a suitable linear polyethylene
homopolymer, or one of the polyethylene standards of known
intrinsic viscosity (traceable to NBS 1475 homopolymer polyethylene
reference sample). The equation for IV(abs) is an area-based result
using the baseline-subtracted specific-viscosity signal (DV) and
the baseline-subtracted IR5 measurement sensor signal (applying the
mass and viscosity constants), as determined from GPCOne.TM.
software:
IV ( Abs ) = i DV i i IR i .times. ( Mass Constant / Viscosity
constant ) . ##EQU00006##
CDF Calculation Method for each Chromatogram
[0080] The calculation of the following; a) cumulative detector
fractions (CDF) from the IRS measurement detector ("CDF.sub.IR"),
b) cumulative detector fractions from the low angle laser light
scattering detector ("CDF.sub.LS"), and c) cumulative detector
fractions from the viscosity detector ("CDF.sub.DV"), were each
determined by the following steps (respectively, visually
represented as FIG. 1, FIG. 2, and FIG. 3 for CDF.sub.IR (IR 5
detector), CDF.sub.LS (LS detector), and CDF.sub.DV (viscosity
detector). 1) Linearly flow correct the chromatogram based on the
relative retention volume ratio of the decane peak between the
sample and that of a consistent narrow standards cocktail mixture.
2) Correct the light scattering detector offset relative to the IR
5 detector, as previously described. See above "Mourey and Balke"
references. 3) Correct the viscosity detector offset relative to
the IR 5 detector, as previously described. See above "Mourey and
Balke" references. 4) Calculate the molecular weights at each
"retention volume (RV) data slice" based on the polystyrene
calibration curve, modified by the polystyrene to polyethylene
conversion factor of approximately (0.43) as described previously,
with a one point (slice) per second, and with a pump running at 1
ml/min. 5) Subtract baselines from each of the viscosity, light
scattering, and infra-red chromatograms, and the integration window
for each was set, making certain to integrate all of the low
molecular weight retention volume range, where the low molecular
weight retention volume range is observable (GPC profile greater
than the baseline) from the infra-red chromatogram (thus setting
the highest RV limit to the same index in each chromatogram).
Material in the integration, which corresponds to a molecular
weight less than 150 g/mole, is not included in any of the
chromatograms. 6) Calculate the respective cumulative detector
fraction (CDF) of the IR5 chromatogram (CDF.sub.IR), LALLS
chromatogram (CDF.sub.LS), and viscosity chromatogram (CDF.sub.DV),
based on the baseline-subtracted peak height (H), from the high to
low molecular weight (low to high retention volume), at each data
slice (j), according to Eqns 8A, 8B, or 8C, respectively:
CDF IR = H j j = RV at 10 , 000 GPC MW j = RV at Highest
Integration Volume H j j = RV at Lowest Integration Volume j = RV
at Highest Integration Volume , ( EQN 8 A ) CDF LS = H j j = RV at
Lowest Integration Volume j = RV at 750 , 000 GPC M W H j j = RV at
Lowest Integration Volume j = RV at Highest Integration Volume , (
EQN 8 B ) CDF DV = H j j = RV at Lowest Integration Volume j = RV
at 1 , 200 , 000 GPC M W H j j = RV at Lowest Integration Volume j
= RV at Highest Integration Volume . ( EQN 8 C ) ##EQU00007##
[0081] FIG. 1 depicts an example determination of the CDF.sub.IR
for Example 1: the fractional area of the IRS measurement sensor
channel of the detector (chromatogram) less than, or equal to,
10,000 g/mol MW, by GPC after baseline subtraction. FIG. 2 depicts
an example determination of the CDF.sub.LS for Example 1: the
fractional area of the 15 degree light scattering signal greater
than, or equal to, 750,000 g/mol MW, by GPC after baseline
subtraction. FIG. 3 depicts an example determination of CDF.sub.DV
for Example 1: the fractional area of the specific viscosity signal
greater than, or equal to, 1,200,000 g/mol MW, by GPC after
baseline subtraction.
gpcBR Branching Index by Triple Detector GPC (TDGPC)
[0082] The gpcBR branching index was determined by first
calibrating the light scattering, viscosity, and concentration
detectors as described previously. Baselines were then subtracted
from the light scattering, viscometer, and concentration
chromatograms. Integration windows were then set, to ensure
integration of all of the low molecular weight retention volume
range in the light scattering and viscometer chromatograms that
indicate the presence of detectable polymer from the refractive
index chromatogram. Linear polyethylene standards were then used to
establish polyethylene and polystyrene Mark-Houwink constants. Upon
obtaining the constants, the two values were used to construct two
linear reference conventional calibrations for polyethylene
molecular weight and polyethylene intrinsic viscosity as a function
of elution volume, as shown in Equations (9) and (10):
M P E = ( K P S K PE ) 1 / .alpha. P + 1 M PS .alpha. PS + 1 /
.alpha. P + 1 , ( EQN 9 ) [ .eta. ] PE = K P S M P S .alpha. + 1 /
M PE . ( EQN 10 ) ##EQU00008##
[0083] The gpcBR branching index is a robust method for the
characterization of long chain branching as described in Yau,
Wallace W., "Examples of Using 3D-GPC--TREF for Polyolefin
Characterization," Macromol. Symp., 2007, 257, 29-45. The index
avoids the "slice-by-slice" 3D-GPC calculations traditionally used
in the determination of g' values and branching frequency
calculations, in favor of whole polymer detector areas. From TDGPC
data, one can obtain the sample bulk absolute weight average
molecular weight (Mw, Abs) by the light scattering (LS) detector,
using the peak area method. The method avoids the "slice-by-slice"
ratio of light scattering detector signal over the concentration
detector signal, as required in a traditional g' determination.
[0084] With TDGPC, sample intrinsic viscosities were also obtained
independently using Equations (11). The area calculation in this
case offers more precision, because, as an overall sample area, it
is much less sensitive to variation caused by detector noise and
3D-GPC settings on baseline and integration limits. More
importantly, the peak area calculation was not affected by the
detector volume offsets. Similarly, the high-precision, sample
intrinsic viscosity (IV) was obtained by the area method shown in
Equation (11):
IV = [ .eta. ] = i w i IV i = i ( C i i C i ) IV i = i C i IV i i C
i = i D P i i C i = DP Area Conc . Area , ( EQN 11 )
##EQU00009##
where DPi stands for the differential pressure signal monitored
directly from the online viscometer.
[0085] To determine the gpcBR branching index, the light scattering
elution area for the sample polymer was used to determine the
molecular weight of the sample. The viscosity detector elution area
for the sample polymer was used to determine the intrinsic
viscosity (IV or [.sub..eta.]) of the sample. Initially, the
molecular weight and intrinsic viscosity for a linear polyethylene
standard sample, such as SRM1475a or an equivalent, were determined
using the conventional calibrations ("cc") for both molecular
weight and intrinsic viscosity as a function of elution volume:
[ .eta. ] c c = i ( C i i C i ) IV i = i w i IV cc , i . ( EQN 12 )
##EQU00010##
Equation (13) was used to determine the gpcBR branching index:
gpc BR = [ ( [ .eta. ] c c [ .eta. ] ) ( M W M W , CC ) .alpha. PE
- 1 ] , ( EQN 13 ) ##EQU00011##
wherein [.sub..eta.] is the measured intrinsic viscosity,
[.eta.].sub.cc is the intrinsic viscosity from the conventional
calibration (or conv GPC), Mw is the measured weight average
molecular weight, and M.sub.w,cc is the weight average molecular
weight of the conventional calibration. The weight average
molecular weight by light scattering (LS) is commonly referred to
as "absolute weight average molecular weight" or "Mw(abs)." The
M.sub.w,cc from using conventional GPC molecular weight calibration
curve ("conventional calibration") is often referred to as "polymer
chain backbone molecular weight," "conventional weight average
molecular weight" and "Mw(conv)."
[0086] All statistical values with the "cc or conv" subscript are
determined using their respective elution volumes, the
corresponding conventional calibration as previously described, and
the concentration (Ci). The non-subscripted values are measured
values based on the mass detector, LALLS, and viscometer areas. The
value of K.sub.PE is adjusted iteratively, until the linear
reference sample has a gpcBR measured value of zero. For example,
the final values for a and Log K for the determination of gpcBR in
this particular case are 0.725 and -3.355, respectively, for
polyethylene, and 0.722 and -3.993, respectively, for polystyrene.
Once the K and .alpha. values have been determined using the
procedure discussed previously, the procedure was repeated using
the branched samples. The branched samples were analyzed using the
final Mark-Houwink constants as the best "cc" calibration values.
The interpretation of gpcBR is straight forward. For linear
polymers, gpcBR will be close to zero, since the values measured by
LS and viscometry will be close to the conventional calibration
standard. For branched polymers, gpcBR will be higher than zero,
especially with high levels of long chain branching, because the
measured polymer molecular weight will be higher than the
calculated M.sub.w,cc, and the calculated IV.sub.cc will be higher
than the measured polymer IV. In fact, the gpcBR value represents
the fractional IV change due to the molecular size contraction
effect as a result of polymer branching. A gpcBR value of 0.5 or
2.0 would mean a molecular size contraction effect of IV at the
level of 50% and 200%, respectively, versus a linear polymer
molecule of equivalent weight. For these particular examples, the
advantage of using gpcBR, in comparison to a traditional "g' index"
and branching frequency calculations, is due to the higher
precision of gpcBR. All of the parameters used in the gpcBR index
determination are obtained with good precision, and are not
detrimentally affected by the low TDGPC detector response at high
molecular weight from the concentration detector. Errors in
detector volume alignment also do not affect the precision of the
gpcBR index determination.
Calculation of LCB frequency
[0087] The LCB.sub.f was calculated for each polymer sample by the
following procedure: 1) The light scattering, viscosity, and
concentration detectors were calibrated with NBS 1475 homopolymer
polyethylene (or equivalent reference). 2) The light scattering and
viscometer detector offsets were corrected relative to the
concentration detector as described above in the calibration
section (see references to Mourey and Balke). 3) Baselines were
subtracted from the light scattering, viscometer, and concentration
chromatograms and set integration windows making certain to
integrate all of the low molecular weight retention volume range in
the light scattering chromatogram that is observable from the
refractometer chromatogram. 4) A linear homopolymer polyethylene
Mark-Houwink reference line was established by injecting a standard
with a polydispersity of at least 3.0, calculate the data file
(from above calibration method), and record the intrinsic viscosity
and molecular weight from the mass constant corrected data for each
chromatographic slice. 5) The LDPE sample of interest was analyzed,
the data file (from above calibration method) was calculated, and
the intrinsic viscosity and molecular weight from the mass
constant, corrected data for each chromatographic slice, were
recorded. At lower molecular weights, the intrinsic viscosity and
the molecular weight data may need to be extrapolated such that the
measured molecular weight and intrinsic viscosity asymptotically
approach a linear homopolymer GPC calibration curve. 6) The
homopolymer linear reference intrinsic viscosity was shifted at
each point (i) by the following factor: IVi=IVi*0.964 where IV is
the intrinsic viscosity. 7) The homopolymer linear reference
molecular weight was shifted by the following factor: M=M*1.037
where M is the molecular weight. 8) The g' at each chromatographic
slice was calculated according to the following equation:
g'=(IV(LDPE)/IV(linear reference)), at the same M. The IV (linear
reference) was calculated from a fifth-order polynomial fit of the
reference Mark-Houwink Plot and where IV(linear reference) is the
intrinsic viscosity of the linear homopolymer polyethylene
reference (adding an amount of SCB (short chain branching) to
account for backbiting through 6) and 7) at the same molecular
weight (M)). The IV ratio is assumed to be one at molecular weights
less than 3,500 g/mol to account for natural scatter in the light
scattering data. 9) The number of branches at each data slice was
calculated according to the following equation:
[ IV L D P E IV linear_reference ] M 1.33 = [ ( 1 + B n 7 ) 1 / 2 +
4 9 B n .pi. ] - 1 l 2 . ##EQU00012##
10) The average LCB quantity was calculated across all of the
slices (i), according to the following equation:
L C B 1000 C = M = 3500 i ( B n i 1 4 0 0 0 c i ) c i .
##EQU00013##
Differential Scanning Calorimetry (DSC)
[0088] Differential Scanning Calorimetry (DSC) can be used to
measure the melting and crystallization behavior of a polymer over
a wide range of temperatures. For example, the TA Instruments Q2000
DSC, equipped with an RCS (refrigerated cooling system) and an
autosampler is used to perform this analysis. During testing, a
nitrogen purge gas flow of 50 ml/min is used. Each sample is melt
pressed into a thin film at about 190.degree. C.; the melted sample
is then air-cooled to room temperature (.about.25.degree. C.). The
film sample was formed by pressing a "0.5 to 0.9 gram" sample at
190.degree. C. at 20,000 lb.sub.f and 10 seconds, to form a "0.1 to
0.2 mil thick" film. A 3-10 mg, six mm diameter specimen was
extracted from the cooled polymer, weighed, placed in an aluminum
pan (about 50 mg), and crimped shut. Analysis was then performed to
determine its thermal properties.
[0089] The thermal behavior of the sample was determined by ramping
the sample temperature up and down to create a heat flow versus
temperature profile. First, the sample was rapidly heated to
180.degree. C., and held isothermal for five minutes, in order to
remove its thermal history. Next, the sample was cooled to
-40.degree. C., at a 10.degree. C./minute cooling rate, and held
isothermal at -40.degree. C. for five minutes. The sample was then
heated to 150.degree. C. (this is the "second heat" ramp) at a
10.degree. C./minute heating rate. The cooling and second heating
curves are recorded. The cooling curve was analyzed by setting
baseline endpoints from the beginning of crystallization to
-20.degree. C. The heating curve was analyzed by setting baseline
endpoints from -20.degree. C. to the end of melting. The values
determined were peak melting temperature (Tm), peak crystallization
temperature (Tc), heat of fusion (Hf) (in Joules per gram), and the
calculated % crystallinity for ethylene-based polymer samples using
the following equations: % Crystallinity=((Hf)/(292 J/g)).times.100
(EQN 14). The heat of fusion and the peak melting temperature are
reported from the second heat curve. The peak crystallization
temperature is determined from the cooling curve.
Film Testing
[0090] The following physical properties were measured on the films
as described in the experimental section. Prior to testing, the
film was conditioned for at least 40 hours (after film production)
at 23.degree. C. (+/-2.degree. C.) and 50% relative humidity (+/-5%
R.H). See Tables 12-14 for the thickness of each film.
[0091] Total (Overall) Haze and Internal Haze: Internal haze and
total haze were measured according to ASTM D 1003-07. Internal haze
was obtained via refractive index matching using mineral oil (1-2
teaspoons), which was applied as a coating on each surface of the
film. A Hazegard Plus (BYK-Gardner USA; Columbia, Md.) was used for
testing. For each test, 5 samples were examined, and an average
reported. Sample dimensions were "6 in.times.6 in".
[0092] 45.degree. Gloss: ASTM D2457-08 (average of five film
samples; each sample "10 in.times.10 in"). Clarity: ASTM D1746-09
(average of five film samples; each sample "10 in.times.10 in"). 2%
Secant Modulus-MD (machine direction) and CD (cross direction):
ASTM D882-10 (average of five film samples in each direction). 1
inch wide test strips are loaded in a tensile testing frame using
line contact grips at a contact point (gauge length) separation of
4 inches. Samples are tested at a crosshead speed of 2 inches/min
up to a nominal stain of 5%.
[0093] MD and CD Elmendorf Tear Strength: ASTM D1922-09. The force
in grams required to propagate tearing across a film or sheeting
specimen is measured using a precisely calibrated pendulum device.
Acting by gravity, the pendulum swings through an arc, tearing the
specimen from a precut slit. The specimen is held on one side by
the pendulum and on the other side by a stationary member. The loss
in energy by the pendulum is indicated by a pointer or by an
electronic scale. The scale indication is a function of the force
required to tear the specimen. The sample used is the `constant
radius geometry` as specified in help1922. Testing would be
typically carried out on samples that have been cut from both the
MD and CD directions. Prior to testing, the sample thickness is
measured at the sample center. A total of 15 specimens per
direction are tested, and the average tear strength is reported.
Samples that tear at an angle greater than 60.degree. from the
vertical are described as `oblique` tears--such tears should be
noted, though the strength values are included in the average
strength calculation.
[0094] MD and CD Tensile Strength: ASTM D882-10 (average of five
film samples in each direction). The samples are loaded onto a
tensile testing frame using line grip jaws (flat rubber on one side
of the jaw and a line grip on the other side of the jaw) set at a
gauge length (line grip to line grip distance) of 2 inches. The
samples are then strained at a crosshead speed of 20 inches/min.
From the resulting load-displacement curve the yield strength and
yield strain, tensile strength and tensile strength at break,
strain at break and energy to break can be determined.
[0095] Dart: ASTM D1709-09. The test result is reported by Method
A, which uses a 1.5'' diameter dart head and 26'' drop height. The
sample thickness is measured at the sample center, and the sample
is then clamped by an annular specimen holder with an inside
diameter of 5 inches. The dart is loaded above the center of the
sample and released by either a pneumatic or electromagnetic
mechanism. Testing is carried out according to the `staircase`
method. If the sample fails, a new sample is tested with the weight
of the dart reduced by a known and fixed amount. If the sample does
not fail, a new sample is tested with the weight of the dart
increased by a known increment. After 20 specimens have been tested
the number of failures is determined. If this number is 10 then the
test is complete. If the number is less than 10, the testing
continues until 10 failures have been recorded. If the number is
greater than 10, testing is continued until the total number of
non-failures is 10. The dart (strength) is determined from these
data as per ASTM D1709.
[0096] Puncture Strength: Puncture was measured on an INSTRON Model
4201 with SINTECH TESTWORKS SOFTWARE Version 3.10. The specimen
size was "6 in.times.6 in," and five measurements were made to
determine an average puncture value. A "100 lb load cell" was used
with a round specimen holder of 4 inch diameter. The puncture probe
was a 1/2 inch diameter, polished, stainless steel ball on a 0.25
inch diameter support rod with a 7.5 inch maximum travel length.
There was no gauge length, and prior to the start of the test, the
probe was as close as possible to, but not touching, the specimen.
The puncture probe was pushed into the centre of the clamped film
at a cross head speed of 10 inches/minute. A single thickness
measurement was made in the centre of the specimen. For each
specimen, the puncture (ftlb.sub.f per in.sup.3) was determined.
The puncture probe was cleaned using a "KIM-WIPE" after each
specimen.
[0097] "Shrink Force Measurement of Low Shrink Force Films", SPE
ANTEC Proceedings, p. 1264 (2008). The shrink tension of film
samples was measured through a temperature ramp test that was
conducted on an RSA-III Dynamic Mechanical Analyzer (TA
Instruments; New Castle, Del.) with a film fixture. Film specimens
of "12.7 mm wide" and "63.5 mm long" were die cut from the film
sample, either in the machine direction (MD) or the cross direction
(CD), for testing. The film thickness was measured by a Mitutoyo
Absolute digimatic indicator (Model C112CEXB). This indicator had a
maximum measurement range of 12.7 mm, with a resolution of 0.001
mm. The average of three thickness measurements, at different
locations on each film specimen, and the width of the specimen,
were used to calculate the film's cross sectional area (A), in
which "A =Width.times.Thickness" of the film specimen that was used
in shrink film testing.
[0098] A standard film tension fixture from TA Instruments was used
for the measurement. The oven of the RSA-III was equilibrated at
25.degree. C., for at least 30 minutes, prior to zeroing the gap
and the axial force. The initial gap was set to 20 mm. The film
specimen was then attached onto both the upper and the lower
fixtures. Typically, measurements for MD only require one ply film.
Because the shrink tension in the CD direction is typically low,
two or four plies of films are stacked together for each
measurement to improve the signal-to-noise ratio. In such a case,
the film thickness is the sum of all of the plies. In this work, a
single ply was used in the MD direction and two plies were used in
the CD direction. After the film reached the initial temperature of
25.degree. C., the upper fixture was manually raised or lowered
slightly to obtain an axial force of -1.0 g. This was to ensure
that no buckling or excessive stretching of the film occurred at
the beginning of the test. Then the test was started. A constant
fixture gap was maintained during the entire measurement. The
temperature ramp started at a rate of 90.degree. C./min, from
25.degree. C. to 80.degree. C., followed by a rate of 20.degree.
C./min, from 80.degree. C. to 160.degree. C. During the ramp from
80.degree. C. to 160.degree. C., as the film shrunk, the shrink
force, measured by the force transducer, was recorded as a function
of temperature for further analysis. The difference between the
"peak force" and the "baseline value before the onset of the shrink
force peak" is considered the shrink force (F) of the film. The
shrink tension of the film is the ratio of the shrink force (F) to
the initial cross sectional area (A) of the film.
EXPERIMENTAL
Preparation of Inventive Ethylene-Based Polymers
[0099] FIG. 4 is a block diagram of the process reaction system
used to produce the inventive ethylene-based polymers (LDPEs). The
process reaction system in FIG. 4 is a partially closed-loop, dual
recycle, high-pressure, low density polyethylene production system.
The process reaction system is comprised of a fresh ethylene feed
line [1], a booster and primary compressor ("Primary"), a
hypercompressor ("Hyper") and a four zone tubular reactor ("4 Zone
reactor"). Stream [3] is heated by a "Pre-heater" to a sufficiently
high temperature, and fed to the front of the reactor. Stream [11]
is fed as a side stream to the reactor. In the reactor,
polymerization is initiated with the help of four mixtures, each
containing one or more free radical initiation systems (see Table
1), which are injected at the inlet of each reaction zone (not
shown). The maximum temperature in each reaction zone is controlled
at a set point, by regulating the feed amount of the mixture of
initiators at the start of each reaction zone. Each reaction zone
has one inlet and one outlet. Each inlet stream consists of the
outlet stream from the previous zone and/or added ethylene-rich
feed stream. Upon completing the polymerization, the reaction
mixture is depressurized and cooled in stream [4]. The process
further consists of a high pressure separator "BPS," which
separates the reaction mixture into an ethylene rich stream [8],
which is cooled and recycled back to the suction of the hyper, and
a polymer rich stream [5], which is sent to the low pressure
separator "LPS" for further separation. In the LPS, the ethylene
rich stream is cooled, and recycled back to the booster ("Booster")
in stream [6]. From the booster, the ethylene is compressed further
by the primary compressor. Feed [2] is then recycled to the suction
of the hypercompressor. The polymer leaving the LPS [7] is further
pelletized and purged. The chain transfer agent "CTA" feed [10] is
injected into the ethylene stream at the discharge of the primary
compressor. Stream [9] is a purge stream used to remove impurities
and/or inerts. Cooling jackets (using high pressure water) are
mounted around the outer shell of the tube reactor and
pre-heater.
[0100] For Inventive Examples 1-4, a mixture containing t-butyl
peroxy-2 ethylhexanoate (TBPO), tert-butyl peroxyacetate (TBPA),
and an iso-paraffinic hydrocarbon solvent (boiling range
171-191.degree. C.; for example, ISOPAR H) was used as the
initiator mixture for the first reaction zone. For the second
reaction zone, a mixture containing di-tert-butyl peroxide (DTBP),
TBPO, TBPA, and the iso-paraffinic hydrocarbon solvent was used.
For the third and fourth reaction zones, a mixture of TBPA, DTBP,
and iso-paraffinic hydrocarbon solvent was used. This data is
summarized in Table 1. Propylene was used as the CTA. The
concentration of the CTA fed to the process was adjusted to control
the melt index of the product.
[0101] It was discovered that these polymerization conditions
produced a "LDPE fractional melt index resin" with a broad
molecular weight distribution (MWD). Table 2 shows that the
polymerization conditions used to form the inventive samples were
relatively low reactor pressures and high reactor peak
temperatures, in order to optimize the molecular weight
distribution of the polymer in the tubular reactor. The molecular
weight of each polymer was also optimized by reducing the CTA
(propylene) concentration fed to the reactor.
[0102] Properties of Inventive Examples and Comparative Examples
are listed in Tables 3-10. Table 3 contains the melt index (I2 or
MI), density, % hexane extractables, and peak melt strength data.
The Inventive Examples exhibit a good and relatively high melt
strength, and provide a good balance of bubble stability, in
combination with high output on blown film lines, and good
mechanical properties. FIG. 5 is a plot of the peak melt strength
versus the melt index for the samples of Table 3, and shows that
these inventive polymers (IE1 through IE4) have a peak melt
strength, at 190.degree. C., greater than "-65*(I.sub.2 at
190.degree. C.)+34 cN", and less than "-65*(I.sub.2 at 190.degree.
C.)+43 cN". The melt index, shown in Table 3, is higher for the
Inventive Examples than for CE1, yet the melt strength of the
Inventive Examples are similar to, or higher than, that of CE1, the
lowest melt index comparative polymer. This is attributed to the
molecular design of the inventive polymers (LDPEs), which is
discussed further. Tables 4 through Table 6 contain the TDGPC data,
illustrating for the inventive polymers the relatively broad
MWD(conv), the broad Mw(conv)/Mn(conv) ratio, and the relatively
high z-average molecular weight, Mz(conv) and high weight average
molecular weight, Mw(conv), all of which contribute to the higher
melt strength and good output on blown film lines, as seen with
these inventive polymers. The Mn(conv) is relatively low for the
inventive polymers as compared to the comparative polymers.
[0103] Table 5 contains the TDGPC-related properties derived from
the LS and viscosity detectors, in conjunction with the
concentration detector. As seen in Table 5, it has been discovered
that the inventive polymers have higher Mw(abs), Mz(abs), and
Mw(abs)/Mw(conv). These higher values correlate with relatively
high melt strength and good output, as seen on blown film lines,
using the inventive polymers. It has been discovered that the
inventive polymers have a high amount of long branching (LCBf
and/or gpcBR), at a high Mw (Mw(abs)), and substantial ultra-high
MW material (Mz(abs)), all of which contribute to the desired melt
strength and improved processibility (for example, increased blown
film output and decreased screen pressure). As mentioned, the melt
strength is similar, or higher, for the Inventive Examples of
higher melt index, as compared to CE1, and this is primarily due to
the design of the inventive polymers as described by the TDGPC
molecular weight features. The design of the inventive polymers is
optimized to give an optimum melt strength, and a good balance of
physical properties, along with good drawability, bubble stability,
and blown film output, when forming films, with or without an
additional polymer, such as a LLDPE. Table 6 contains several
unique TDGPC properties, which further reflect the differences in
structure between the Inventive Examples and Comparative Examples.
The CDF.sub.IR, CDF.sub.LS, and CDF.sub.DV determinations are from
the fractional baseline-subtracted chromatographic areas, versus
the whole chromatogram, using the limits as expressed in Equations
8A, 8B, and 8C above. The Mw(abs) is determined from the
mass-normalized area of the baseline-subtracted 15 degree light
scattering signal, and the IV(Abs) is determined from the
mass-normalized area of the baseline-subtracted specific viscosity
chromatogram. The Mw(abs) is compared (ratio taken) against the
conventional weight-average molecular weight (Mw(conv)), and this
ratio is an indication of the total molecular weight (including all
branching) to the backbone molecular weight of the polymer. It has
been discovered that ethylene-based polymers that contain higher
Mw(abs)/Mw(conv) ratios, along with higher Mz(abs) values
(indicating high molecular weight branched content), having
discernible chromatographic high MW area (as indicated by a high
CDF.sub.LS value), an adequate supply of high MW detectable
backbone segments (as indicated by a high CDF.sub.DV value), while
possessing enough low molecular weight material (as indicated by a
high CDF.sub.IR value) to maintain excellent processing, are
preferred to obtain a good melt strength/processibility
balance.
[0104] The CDF.sub.LS is a simple means to define high MW highly
long chain branched content (no detector division, extrapolations,
or advanced calculations necessary). The CDF.sub.DV is a simple
means to describe the amount of polymer segments that are available
for entanglements (such segments are discernible using the
viscosity response). The CDF.sub.IR is a simple means to describe
the enhanced processing found by increasing the low molecular
weight content. The IV(abs) and Mw(abs) are each a general means to
quantitate the polymer constituents giving rise to viscosity at
lower shear rates.
[0105] Table 7 contains the DMS viscosity data, as summarized by
the viscosities measured at 0.1, 1, 10, and 100 rad/s, the
viscosity ratio, or the ratio of viscosity measured at 0.1 rad/s to
the viscosity measured at 100 rad/s, all being measured at
190.degree. C., and the tan delta measured at 0.1 rad/s and
190.degree. C. The inventive polymers each had a relatively high
"low frequency viscosity, the viscosity at 0.1 rad/s" values. A
high "low frequency viscosity" may be correlated with good melt
strength, good bubble stability, and high film output. Thus, these
Inventive Examples still show very good melt strength and very high
output on blown film lines, as compared to the comparative
polymers, some of which had even higher "low frequency viscosity"
values. The viscosity ratio, which reflects the change in viscosity
with frequency, is, like the low frequency viscosity, relatively
high for the inventive polymers, but not always as high as that for
some of the comparative polymers. The high ratio values are
reflective of the good processability of the Inventive Examples
when making blown film. The tan delta, at 0.1 rad/s, values of the
inventive polymers are relatively low, indicative of high melt
elasticity, which may also be correlated with good blown film
bubble stability.
[0106] Table 8 contains the branches per 1000 total carbons as
measured by .sup.13C NMR. These LDPE polymers contain amyl, or C5
branches, which are not contained in substantially linear
polyethylenes, such as AFFINITY Polyolefin Plastomers, or the
LLDPEs, such as DOWLEX Polyethylene Resins, both produced by The
Dow Chemical Company. Each inventive and comparative LDPE, shown in
Table 8, contains greater than, or equal to, 0.5 amyl groups
(branches) per 1000 total carbon atoms (the Inventive Examples
contain greater than 1 amyl groups (branches) per 1000 total carbon
atoms). The Inventive Examples contain relatively low levels of C1
per 1000 total carbon atoms, in which C1 is attributable to the
propylene used as a CTA. The Comparative Examples contain either
much higher levels of C1 per 1000 total carbon atoms, or no C1 is
detected. The Inventive Examples are also shown to contain the
highest levels of 1,3-diethyl branches per 1000 total carbon atoms,
the highest levels of C2 on the quaternary carbon per 1000 total
carbon atoms, the highest levels of C4 per 1000 total carbon atoms,
high levels of C5 (amyl group) per 1000 total carbon atoms, and
high levels of C6+ per 1000 total carbon atoms. Table 9 contains
unsaturation results by .sup.1H NMR. Table 10 contains the DSC
results of the melting point, T.sub.m, the heat of fusion, the
percent crystallinity, and the crystallization point, T.sub.c.
TABLE-US-00002 TABLE 1 Peroxide (PO) initiator flows, in pounds per
hour, at each injection point. Example 1 Example 2 Example 3
Example 4 Neat PO Neat PO Neat PO Neat PO Reaction Zone Initiator
lbs/hour lbs/hour lbs/hour lbs/hour #1 TBPO 3.3 3.5 3.6 3.1 #1 TBPA
1.4 1.5 1.5 1.3 #2 TBPO 9.0 8.6 8.8 8.8 #2 TBPA 2.6 2.5 2.5 2.5 #2
DTBP 1.3 1.2 1.3 1.3 #3 TBPA 4.6 4.6 4.6 5.0 #3 DTBP 10.8 10.7 10.8
11.7 #4 TBPA 2.0 2.0 1.9 1.9 #4 DTBP 4.6 4.7 4.4 4.5
TABLE-US-00003 TABLE 2 Process conditions used to polymerize
Examples (T = temperature). Process Variables Ex. 1 Ex. 2 Ex. 3 Ex
4 Reactor Pressure (Psig) 31,518 31,545 31,429 31,530 Zone 1
Initiation T (.degree. C.) 143 143 143 143 Zone 1 Peak T (.degree.
C.) 277 277 277 275 Zone 2 Initiation T (.degree. C.) 155 153 153
153 Zone 2 Peak T (.degree. C.) 303 303 303 303 Zone 3 Initiation T
(.degree. C.) 264 260 259 267 Zone 3 Peak T (.degree. C.) 304 302
301 303 Zone 4 Initiation T (.degree. C.) 270 269 270 270 Zone 4
Peak T (.degree. C.) 295 295 295 295 Fresh ethylene Flow (lb/hr)
25,560 25,450 25,051 27,570 Ethylene Throughput to Reactor (lb/hr)
101,304 101,360 101,260 101,173 Ethylene Conversion (%) 25.1 25.1
24.8 25.3 Propylene Flow (lb/hr) 36 36 36 36 Ethylene Purge Flow
(lb/hr) 580 498 499 1,710 Recycle Prop Conc. (% Vol) 0.071 0.079
0.072 0.066 Pre-heater T (.degree. C.) 200 200 200 200 Reactor
Cooling System 1 T (.degree. C.) 188 188 188 188 Reactor Cooling
System 2 T (.degree. C.) 185 185 185 185
TABLE-US-00004 TABLE 3 Melt index (I.sub.2), density, % hexane
extractables, and peak melt strength (MS) at 190.degree. C. and of
Examples (Ex.) and Comparative Examples (CE) Hexane Peak Melt
I.sub.2 Density Extractables Strength Sample (g/10 min) (g/cc) (%)
(cN) Ex. 1 0.22 0.9205 2.04 26.1 Ex. 2 0.24 0.9202 1.96 23.9 Ex. 3
0.27 0.9202 2.05 24.3 Ex. 4 0.17 0.9194 2.18 29.9 CE 1* 0.13 0.9206
1.36 24.2 CE 2** 0.24 0.9211 1.54 28.6 CE 3*** 0.21 0.9205 1.12
18.3 *AGILITY 1000 available from the Dow Chemical Company. **LDPE
150E available from The Dow Chemical Company. ***LDPE 132I
available from the Dow Chemical Company.
TABLE-US-00005 TABLE 4 Conventional GPC properties of Examples
(Ex.) and Comparative Examples (CE) Mn(conv) Mw(conv) Mz(conv)
Mw(conv)/ Sample (g/mol) (g/mol) (g/mol) Mn(conv) Ex. 1 15,100
160,500 679,200 10.6 Ex. 2 15,100 160,100 681,000 10.6 Ex. 3 15,200
157,600 674,700 10.4 Ex. 4 15,100 169,300 727,400 11.2 CE 1 17,800
136,500 477,300 7.68 CE 2 16,800 137,400 413,200 8.17 CE 3 17,700
107,600 362,600 6.08
TABLE-US-00006 TABLE 5 Absolute GPC calibration of Examples (Ex.)
and Comparative Examples (CE). Mw(abs) Mz(abs) Mz(abs)/ Mw(abs)/
(g/mol) (g/mol) Mw(abs) Mw(conv) LCBf gpcBR Ex. 1 439,400 5,098,000
11.6 2.74 3.46 3.01 Ex. 2 446,200 5,267,000 11.8 2.79 3.70 3.10 Ex.
3 442,200 5,126,000 11.6 2.81 3.56 3.12 Ex. 4 488,100 5,663,000
11.6 2.88 4.04 3.24 CE 1 305,900 3,760,000 12.3 2.24 2.55 2.18 CE 2
244,500 1,133,000 4.64 1.78 2.58 1.84 CE 3 217,300 3,676,000 16.9
2.02 2.25 1.70
TABLE-US-00007 TABLE 6 TDGPC-related properties related to IR, LS,
and DV CDF.sub.IR CDF.sub.LS CDF.sub.DV (MW below (MW above (MW
above IV (Abs) 10,000 g/mol) 750,000 g/mol) 1,200,000 g/mol) (g/dl)
Ex. 1 0.155 0.531 0.061 1.133 Ex. 2 0.154 0.524 0.057 1.123 Ex. 3
0.155 0.522 0.053 1.112 Ex. 4 0.156 0.551 0.068 1.148 CE 1 0.129
0.378 0.023 1.138 CE 2 0.137 0.233 0.016 1.114 CE 3 0.130 0.311
0.011 1.054
TABLE-US-00008 TABLE 7 Viscosities in Pa s at 0.1, 1, 10, and 100
rad/s, the viscosity ratio, and the tan delta at 190.degree. C.
Visc Visc Visc Visc Visc. Tan Delta 0.1 1 10 100 Ratio 0.1 rad/s
rad/s rad/s rad/s V0.1/V100 rad/s Ex. 1 35,240 11,797 3,158 721
48.86 1.30 Ex. 2 33,726 11,557 3,127 719 46.88 1.34 Ex. 3 32,278
11,217 3,069 712 45.34 1.37 Ex. 4 40,514 13,040 3,372 751 53.92
1.20 CE 1 53,324 16,903 4,230 916 58.21 1.21 CE 2 35,769 12,527
3,410 783 45.65 1.39 CE 3 42,113 15,001 4,049 917 45.91 1.48
TABLE-US-00009 TABLE 8 Branching results in branches per 1000 C by
.sup.13C NMR 1,3 C2 on diethyl Quat Sample C1 branches Carbon C4 C5
C6+ Ex. 1 0.37 4.48 1.47 6.82 2.14 3.5 Ex. 2 0.44 4.59 1.58 6.8 2.1
3.3 Ex. 3 0.35 4.23 1.51 6.8 2.02 3.2 Ex. 4 0.34 4.61 1.6 6.9 2.19
3.5 CE 1 1.69 3.65 1.43 6.23 1.74 2.7 CE 2 ND 3.73 1.44 6.58 2.16
3.3 CE 3 2.6 3.41 1 6.13 1.74 2.3 CE 4* ND*** ND ND ND ND
19.5.sup.A CE 5** ND ND ND ND ND 11.4.sup.A .sup.AThe values in the
C6+ column for the DOWLEX and AFFINITY samples represent C6
branches from octene only, and do not include chain ends. *AFFINITY
PL 1880 available from The Dow Chemical Company. **DOWLEX 2045G
available from The Dow Chemical Company. ***ND = not detected.
TABLE-US-00010 TABLE 9 Unsaturation results by .sup.1H NMR of
Examples and Comparative Examples. cis and total vinyl/ trans/
trisub/ vinylidene/ unsaturation/ 1000 C 1000 C 1000 C 1000 C 1000
C Ex. 1 0.074 0.046 0.1 0.217 0.44 Ex. 2 0.058 0.044 0.067 0.196
0.36 Ex. 3 0.059 0.037 0.067 0.202 0.36 Ex. 4 0.061 0.043 0.065
0.209 0.38 CE 1 0.127 0.035 0.042 0.162 0.37 CE 2 0.037 0.033 0.062
0.148 0.28 CE 3 0.17 0.04 0.026 0.13 0.36 CE 4 0.04 0.064 0.123
0.043 0.27 CE 5 0.283 0.049 0.042 0.055 0.43
TABLE-US-00011 TABLE 10 DSC results of Examples and Comparative
Examples. T.sub.m Heat of T.sub.c (.degree. C.) Fusion (J/g) %
Crystallinity (.degree. C.) Ex. 1 110.2 141.5 48.5 98.8 Ex. 2 110.0
144.7 49.6 98.9 Ex. 3 110.1 146.1 50.0 98.8 Ex. 4 109.7 143.4 49.1
98.9 CE 1 109.2 139.9 47.9 98.1 CE 2 110.0 142.5 48.8 98.5 CE 3
109.2 144.0 49.3 97.3
Film Formulations
[0107] Blown films were made, and physical properties measured,
with different LDPEs and one LLDPE1 (DOWLEX 2045G). LLDPE1 had a
"1.0 melt index (MI or I2), and a 0.920 g/cc density." Films were
made at 10 wt %, 20 wt %, and 50 wt % of the respective LDPE, based
on the weight of the LDPE and LLDPE1. Each formulation was
compounded on a MAGUIRE gravimetric blender. A polymer processing
aid (PPA), DYNAMAR FX-5920A, was added to each formulation. The PPA
was added at "1.125 wt % of masterbatch," based on the total weight
of the weight of the formulation. The PPA masterbatch (Ingenia
AC-01-01, available from Ingenia Polymers) contained 8 wt % of
DYNAMAR FX-5920A in a polyethylene carrier. This amounts to 900 ppm
PPA in the polymer. LLDPE1 was also used as the LLDPE in the films
made at maximum output. Samples were run at maximum output with 80
wt % DOWLEX 2045G and 20 wt % LDPE and 90 wt % DOWLEX 2045G and 10
wt % LDPE.
Production of Blown Films
[0108] The monolayer blown films were made on an "8 inch die" with
a polyethylene "Davis Standard Barrier II screw." External cooling
by an air ring and internal bubble cooling were used. General blown
film parameters, used to produce each blown film, are shown in
Table 11. The temperatures are the temperatures closest to the
pellet hopper (Barrel 1), and in increasing order, as the polymer
was extruded through the die.
TABLE-US-00012 TABLE 11 Blown film fabrication conditions for
films. Blow up ratio (BUR) 2.5 Film thickness (mil) 2.0 Die gap
(mil) 70 Air temperature (.degree. F.) 45 Temperature profile
(.degree. F.) Barrel 1 350 Barrel 2 415 Barrel 3 365 Barrel 4 305
Barrel 5 305 Screen Temperature 410 Adapter 410 Block 430 Lower Die
440 Inner Die 440 Upper Die 440
Production of Films for Determination of Maximum Output Rate of
Blown Film
[0109] Film samples were made at a controlled rate and at a maximum
rate. The controlled rate was 250 lb/hr, which equals an output
rate of 10.0 lb/hr/inch of die circumference. The die diameter used
for the maximum output trials was an 8 inch die, so that for the
controlled rate, as an example, the conversion between "lb/hr" and
"lb/hr/inch" of die circumference, is shown in Equation 15.
Similarly, such an equation can be used for other rates, such as
the maximum rate, by substituting the maximum rate in Equation 15
to determine the "lb/hr/inch" of die circumference.
Lb/Hr/Inch of Die Circumference=(250 Lb/Hr)/(8*.pi.)=10 (Eq.
15).
[0110] The maximum rate for a given sample was determined by
increasing the output rate to the point where bubble stability was
the limiting factor. The extruder profile was maintained for both
samples (standard rate and maximum rate), however the melt
temperature was higher for the maximum rate samples, due to the
increased shear rate with higher motor speed (rpm, revolutions per
minute). The maximum bubble stability was determined by taking the
bubble to the point where it would not stay seated in the air ring.
At that point, the rate was reduced to where the bubble was
reseated in the air ring, and then a sample was collected. The
cooling on the bubble was adjusted by adjusting the air ring and
maintaining the bubble. This was taken as the maximum output rate,
while maintaining bubble stability. Film properties are listed in
Tables 12-14. As seen in these tables, the Inventive Examples when
blended with LLDPE1, have excellent output (maximum output, shown
at 10% and 20% LDPE) along with good optics/haze, dart, puncture,
and tear. Thus, improved output is seen with the Inventive
Examples, when blended with LLDPE1, while maintaining acceptable
optics and toughness properties. Additionally, the Inventive
Examples, when blended with LLDPE1, show good shrink properties
(shrink tension, free shrink). Additionally, especially for
Inventive Example 3, the screen pressure (in psi) is the lowest of
any sample tested, showing the improved processability of this
resin.
TABLE-US-00013 TABLE 12 Film properties of "100% LLDPE1" Film #1,
and "90 wt % LLDPE1/10 wt % LDPE" Films #2-6, each made at 2 mil at
a standard (std.) rate of 250 lb/hr. Note, the melt temperature,
screen pressure and output were each measured at a maximum (max.)
rate. Film 1 2 3 4 5 6 LDPE NA CE 3 CE 1 Ex. 3 Ex. 4 CE 2 Thickness
(mil) 1.97 2.05 1.99 2.10 1.98 2.08 Melt Index I.sub.2 1.01 0.92
0.80 0.94 0.86 0.81 Melt Index Ratio I.sub.10/I.sub.2 7.76 7.87
8.27 7.53 8.01 8.12 Density (g/cc) 0.922 0.923 0.923 0.923 .sup.
0.923 0.923 Haze (%) 11.1 7.7 7.7 8.6 8.8 7.8 Haze Internal (%) 4.6
3.4 3.4 3.2 3.2 3.1 Gloss (45.degree.) 55.8 66.9 68.7 62.6 61.1
66.7 Clarity (%) 98.6 99.2 99.0 97.8 97.5 98.4 Dart (g) 412 367 331
334 310 310 Puncture (ft-lb.sub.f/in.sup.3) 183 207 186 189 213 187
MD Tear (g) 842 599 602 627 612 542 CD Tear (g) 1,092 1,353 1,312
1,250 1,255 1,352 MD Normalized Tear (g/mil) 442 301 307 321 313
277 CD Normalized Tear (g/mil) 561 691 667 637 652 685 2% MD Secant
Modulus (psi) 27,316 29,254 27,850 28,407 29,218 27,834 2% CD
Secant Modulus (psi) 32,440 31,868 30,679 32,482 34,791 33,266 MD
Free Shrink (%) 60.2 71.5 72.5 72.0 71.0 73.4 CD Free Shrink (%)
7.5 2.6 1.6 1.6 4.5 3.1 MD Shrink Tension (psi) 2.71 5.77 6.33 6.99
5.80 7.93 CD Shrink Tension (psi) 0.52 0.48 0.53 0.40 0.54 0.45
Frost Line Height (inches) 30 30 31 31 31 33 Melt Temperature
(.degree. F.) 409 407 409 408 408 408 Screen Pressure (psi) 3,610
3,360 3,530 3,270 3,430 3,490 Standard output (lb/hr) 248 251 253
250 252 250 Frost Line Height (inches), Max 52 67 82 77 85+ 33
Output Melt Temperature (.degree. F.), Max 422 431 442 440 446 444
Output Screen Pressure (psi), Max Output 3,980 4,080 4,470 4,660
4,620 4,450 Output (lb/hr), Max Output 319 395 429 428 455 444
TABLE-US-00014 TABLE 13 Film properties of "80 wt % LLDPE1/20 wt %
LDPE" Films #7-11, each made at 2 mil at a standard (std.) rate of
250 lb/hr; note the melt temperature, screen pressure and output
were each measured at a maximum (max.) rate. Film 7 8 9 10 11 LDPE
CE 3 CE 1 Ex. 3 Ex. 4 CE 2 Thickness (mil) 2.04 1.90 1.97 2.02 1.97
Melt Index I.sub.2 0.74 0.68 0.78 0.72 0.78 Melt Index Ratio
I.sub.10/I.sub.2 8.50 9.34 8.47 8.73 8.73 Density (g/cc) 0.923
0.922 0.923 0.922 0.923 Haze (%) 7.9 8.2 9.3 13.4 7.7 Haze Internal
(%) 2.8 2.5 2.6 2.4 2.5 Gloss (45.degree.) 63.1 61.5 57.3 43.6 62.9
Clarity (%) 97.3 95.4 94.4 85.7 95.6 Dart (g) 283 295 286 271 283
Puncture (ft-lb.sub.f/in.sup.3) 183 183 171 164 182 MD Tear (g) 430
355 440 361 403 CD Tear (g) 1,397 1,258 1,250 1,107 1,204 MD
Normalized Tear (g/mil) 212 183 220 187 216 CD Normalized Tear
(g/mil) 703 648 656 578 644 2% MD Secant Modulus (psi) 28,902
28,398 27,486 27,410 27,138 2% CD Secant Modulus (psi) 34,496
26,953 33,753 33,137 31,665 MD Free Shrink (%) 73.4 75.9 72.5 75.4
76.9 CD Free Shrink (%) 3.5 0.6 3.6 8.5 3.1 MD Shrink Tension (psi)
9.60 11.43 8.88 12.28 10.22 CD Shrink Tension (psi) 0.27 0.46 0.35
0.38 0.37 Frost Line Height (inches) 31 30 30 29 29 Melt
Temperature (.degree. F.) 410 408 409 407 407 Screen Pressure (psi)
3,730 3,650 3,190 3,760 3,700 Standard Output (lb/hr) 254 250 252
253 251 Frost Line Height (inches), Max Output 60 80 70 90 90 Melt
Temperature (.degree. F.), Max Output 440 448 450 454 454 Screen
Pressure (psi), Max Output 4,480 4,630 4,550 4,620 4,370 Output
(lb/hr), Max Output 430 483 501* 535** 541 *Ran out of sample; max
rate higher than reported in table. **Stopped due to no BUR
control; max rate higher than reported in the table.
TABLE-US-00015 TABLE 14 Film properties of "50 wt % LLDPE1/50 wt %
LDPE" Films #12- 16, each made at 2 mil at a standard (std.) rate
of 250 lb/hr. Film 12 13 14 15 16 LDPE CE 3 CE 1 Ex. 3 Ex. 4 CE 2
Thickness (mil) 1.94 2.05 1.90 1.96 2.07 Melt Index I.sub.2 0.49
0.39 0.47 0.45 0.44 Melt Index Ratio I.sub.10/I.sub.2 10.78 11.43
11.17 10.49 10.91 Density (g/cc) 0.923 0.922 0.923 0.922 0.923 Haze
(%) 10.6 11.7 20.0 24.1 14.8 Haze Internal (%) 1.8 1.6 1.7 1.5 1.5
Gloss (45.degree.) 50.7 47.0 30.5 24.7 37.5 Clarity (%) 89.7 87.5
74.0 68.3 80.4 Dart (g) 229 250 223 214 232 Puncture
(ft-lb.sub.f/in.sup.3) 149 124 133 128 124 MD Tear (g) 140 127 131
124 116 CD Tear (g) 1,037 1,116 943 997 1,056 MD Normalized Tear
(g/mil) 71 64 66 61 59 CD Normalized Tear (g/mil) 527 557 472 492
540 2% MD Secant Modulus (psi) 30,004 28,861 28,908 30,226 31,238
2% CD Secant Modulus (psi) 35,270 33,848 36,114 37,603 38,741 MD
Free Shrink (%) 81.8 82.3 80.8 81.8 83.3 CD Free Shrink (%) 15.4
15.4 18.3 14.4 14.9 MD Shrink Tension (psi) 26.93 35.60 27.98 33.03
36.45 CD Shrink Tension (psi) 0.47 0.67 0.41 0.51 0.51 Frost Line
Height (inches) 28 28 25 24 26 Melt Temperature (.degree. F.) 417
417 414 417 418 Screen Pressure (psi) 3,730 3,710 3,480 3,730 3,890
Standard Output (lb/hr) 301 301 302 301 300
* * * * *