U.S. patent application number 13/376047 was filed with the patent office on 2012-04-19 for ethylenic polymer and its use.
This patent application is currently assigned to Dow Global Technologies LLC. Invention is credited to Sharon Baker, Robert N. Cotton, Tianzi Huang, Pradeep Jain, Matthew Lehr, Rajen M. Patel, Jeffrey A. Sims, Jian Wang.
Application Number | 20120095158 13/376047 |
Document ID | / |
Family ID | 43017110 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120095158 |
Kind Code |
A1 |
Patel; Rajen M. ; et
al. |
April 19, 2012 |
ETHYLENIC POLYMER AND ITS USE
Abstract
New ethylene polymers having low levels of long chain branching
are disclosed. Films and film layers made form these polymers have
good hot tack strength over a wide range of temperatures, making
them good materials for packaging applications.
Inventors: |
Patel; Rajen M.; (Lake
Jackson, TX) ; Cotton; Robert N.; (Missouri City,
TX) ; Baker; Sharon; (Lake Jackson, TX) ;
Jain; Pradeep; (Lake Jackson, TX) ; Wang; Jian;
(Rosharon, TX) ; Sims; Jeffrey A.; (Lake Jackson,
TX) ; Huang; Tianzi; (Lake Jackson, TX) ;
Lehr; Matthew; (Lake Jackson, TX) |
Assignee: |
Dow Global Technologies LLC
Midland
MI
|
Family ID: |
43017110 |
Appl. No.: |
13/376047 |
Filed: |
July 1, 2010 |
PCT Filed: |
July 1, 2010 |
PCT NO: |
PCT/US10/40759 |
371 Date: |
December 2, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61222367 |
Jul 1, 2009 |
|
|
|
Current U.S.
Class: |
524/579 ;
525/240; 525/55; 525/95; 526/348.2 |
Current CPC
Class: |
B32B 5/08 20130101; C08F
10/00 20130101; C08F 4/65912 20130101; C08F 210/16 20130101; C08J
2323/08 20130101; C08L 2666/24 20130101; B32B 2262/0207 20130101;
C08L 2312/00 20130101; B32B 27/18 20130101; C08L 23/0815 20130101;
B32B 2262/023 20130101; B32B 2262/12 20130101; C08F 10/00 20130101;
B32B 25/06 20130101; C08F 210/16 20130101; C08F 210/16 20130101;
B32B 5/024 20130101; B32B 2262/0253 20130101; B32B 2555/02
20130101; C08J 5/18 20130101; B32B 27/20 20130101; B32B 2581/00
20130101; B32B 27/06 20130101; B32B 27/308 20130101; B32B 2471/00
20130101; B32B 27/302 20130101; B32B 5/24 20130101; B32B 27/22
20130101; B32B 27/32 20130101; B32B 27/327 20130101; B32B 27/306
20130101; B32B 2437/02 20130101; B32B 2405/00 20130101; C08L
23/0815 20130101; B32B 2307/30 20130101; B32B 2605/003 20130101;
B32B 2270/00 20130101; B32B 2307/31 20130101; B32B 2307/714
20130101; B32B 2553/00 20130101; B32B 5/022 20130101; B32B 2597/00
20130101; C08L 53/02 20130101; C08F 2500/08 20130101; C08F 2/06
20130101; C08F 2500/19 20130101; C08F 4/659 20130101; C08F 210/14
20130101; C08F 4/64193 20130101; C08F 2500/12 20130101; C08L
2666/24 20130101; C08F 4/65908 20130101; B32B 2307/72 20130101;
B32B 2605/00 20130101; B32B 2307/50 20130101; C08F 2500/03
20130101; C08F 10/00 20130101; C08F 2500/17 20130101 |
Class at
Publication: |
524/579 ;
526/348.2; 525/55; 525/95; 525/240 |
International
Class: |
C08L 23/20 20060101
C08L023/20; C08F 8/00 20060101 C08F008/00; C08L 53/00 20060101
C08L053/00; C08F 10/14 20060101 C08F010/14 |
Claims
1. An ethylenic polymer having: an overall polymer density of not
more than 0.905 g/cm.sup.3; a GI200 gel rating of not more than 15;
110/12 (measured at 190.degree. C.) from about 5.8 to about 6.5,
preferably from about 5.9 to about 6.5; a zero shear viscosity
(ZSV) ratio of from about 1.3 to about 2.3, preferably from about
1.4 to about 2.2, most preferably from about 1.5 to about 2.1; and
Mw/Mn of from about 2.0 to about 2.4, preferably from about 2.1 to
about 2.3; and a g'(HMW)/g'(LMW) of greater than 0.95.
2. The ethylenic polymer of claim 1 further comprising a have melt
index (190.degree. C., 2.16 kg load) from about 0.5 to about 15
gms/10 minutes, preferably from about 0.7 to about 12.
3. The ethylenic polymer of claim 1 further comprising a DSC
melting point defined by the relationship, Tm(.degree.
C.).ltoreq.(-7914.1*(density)2)+(15301*density)-7262.4, where
density is in g/cc.
4. The ethylenic polymer of claim 1 wherein the density is from
about 0.857 g/cc to 0.905 g/cc, preferably from about 0.865 g/cc to
0.905 g/cc, most preferably from about 0.885 g/cc to 0.905
g/cc.
5. A composition comprising, or made from, at least one ethylenic
polymer of claim 1, wherein at least a portion of the ethylenic
polymer has been cross-linked.
6. A composition comprising, or made from, at least one ethylenic
polymer of claim 1, in which at least a portion of the ethylenic
polymer has been functionalized.
7. A composition comprising, or made from, at least one ethylenic
polymer of claim 1 and at least one other natural or synthetic
polymer.
8. The composition of claim 11 in which at least one of the other
natural or synthetic polymer(s) is selected from the group
consisting of at least one thermoplastic or elastomeric olefin
polymer and at least one styrenic block copolymer.
9. A composition comprising, or made from, at least one ethylenic
polymer of claim 1 and at least one other component selected from
the group consisting of a tackifier, a wax, and an oil.
10. A composition comprising a dispersion or emulsion of particles
in a fluid, wherein the particles comprise, or are made from, at
least one ethylenic polymer of claim 1.
11. A fabricated article in which at least one layer or portion of
the fabricated article comprises, or is made from, at least one
ethylenic polymer of claim 1.
12. The fabricated article of claim 10 in which the fabricated
article comprises a film, a sheet, a fiber, a nonwoven, a laminate,
or a composite.
13. The fabricated article of claim 11 in which the article is a
multilayer film and the layer of the film that comprises, or is
made from, the at least one ethylenic polymer has a peak hot tack
in (N/inch) is greater than or equal to the quantity (13-0.395*12)
at a seal bar temperature of from 90 to 140 C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Application No. 61/222,367, filed on Jul. 1, 2009 and a
second filed U.S. Provisional Application No. 61/222,367 filed on
Aug. 7, 2009, and fully incorporated herein.
BACKGROUND OF THE INVENTION
[0002] Metallocene-catalyzed polymers have been commercial for
several years, and are used in many end-use applications, such as
packaging, personal hygiene, automotive, flooring, adhesives,
fibers, nonwovens, films, sheets, and fabrics. The
metallocene-catalyzed polymers have certain advantages, such as
narrow molecular weight distributions. Some of the
metallocene-catalyzed polymers are homogeneous polymers that have
long chain branching which enhances their processability. However,
metallocene-catalyzed polymers are still subject to degradation
under ultraviolet light and have cross-linking characteristics that
make their use in certain applications more challenging. Further,
those metallocene-catalyzed polymers which have relatively high
levels of long chain branching typically exhibit poor hot tack
strength and/or a narrow sealing window, which renders them less
useful in certain film applications.
[0003] Known metallocene-catalyzed polymers include both (a) the
homogeneous-branched, substantially linear ethylene polymers
("SLEP") which are prepared using constrained geometry catalysts
("CGC Catalyst"), such as disclosed in U.S. Pat. No. 5,272,236 and
U.S. Pat. No. 5,278,272, and WO93/08221, as well as the homogeneous
linear ethylene polymers ("LEP") which are prepared using other
metallocene (called "bis-CP catalysts"). Various grades of SLEPs,
having a variety of densities and melt flow rates, are commercially
available from The Dow Chemical Company as ENGAGE.TM. polyolefin
elastomers or AFFINITY.TM. plastomers. Various grades of LEPs are
commercially available from ExxonMobil Chemical Company as EXAC.TM.
or EXCEED.TM. polymers.
[0004] A characteristic of metallocene-catalyzed polymers is that
they have a significant level (typically in excess of 300 wppm) of
residual unsaturation, with that unsaturation being in various
combinations and amounts of one or more of the following
unsaturated groups:
[0005] Vinyl, vinylidene, vinylene, vinyl-3, and tri-substituted
vinyls.
[0006] Such residual unsaturations, and particularly the vinyl-3
groups, are believed to contribute to long-term polymer
degradation, as well as to difficulties in controlling either or
both of desired cross-linking in some applications or undesired
cross-linking (such as the formation of gels) in other end-use
applications (such as films).
[0007] Further, for film applications, it is desirable to have a
broad thermal bonding window (temperature range) as well as
relatively low hot tack initiation temperature.
BRIEF SUMMARY OF THE INVENTION
[0008] This invention is related to new essentially linear
polyethylene resins having a very low level of long chain
branching. Such resins have 110/12 (measured at 190.degree. C.)
from about 5.8 to about 6.5, preferably from about 5.9 to about
6.5; a zero shear viscosity (ZSV) ratio of from about 1.3 to about
2.3, preferably from about 1.4 to about 2.2, most preferably from
about 1.5 to about 2.1 and Mw/Mn of from about 2.0 to about 2.4,
preferably from about 2.1 to about 2.3. Such resins can have melt
index (190.degree. C., 2.16 kg load) from about 0.5 to about 15
grams/10 minutes, preferably from about 0.7 to about 12. Such
resins can also have a DSC melting point defined by the
relationship,
[0009] Tm (.degree.
C.).ltoreq.(-7914.1*(density)2)+(15301*density)-7262.4, where
density is in g/cc. The density of the polymers can be from about
0.857 g/cc to 0.905 g/cc, preferably from about 0.865 g/cc to 0.905
g/cc, most preferably from about 0.885 g/cc to 0.905 g/cc.
[0010] In a first aspect of the invention, there is provided an
ethylenic polymer comprising.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows hot tack data for two ethylenic polymers of the
invention made into film layers and for a comparative example.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0012] "Composition," as used, includes a mixture of materials
which comprise the composition, as well as reaction products and
decomposition products formed from the materials of the
composition.
[0013] "Blend" or "polymer blend," as used, mean an intimate
physical mixture (that is, without reaction) of two or more
polymers. A blend may or may not be miscible (not phase separated
at 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).
[0014] "Linear," as used, refers to polymers where the polymer
backbone of the polymer lacks measurable or demonstrable long chain
branches, for example, the polymer is substituted with an average
of less than 0.01 long branch per 1000 carbons.
[0015] "Polymer" refers to a polymeric composition prepared by
polymerizing monomers, whether of the same or a different type. The
generic term "polymer" thus embraces the term "homopolymer,"
usually employed to refer to polymers prepared from only one type
of monomer, and the term "interpolymer" as defined. The terms
"ethylene/.alpha.-olefin polymer" is indicative of interpolymers as
described.
[0016] "Interpolymer," as used, refers to polymers prepared by the
polymerization of at least two different types of monomers. The
generic term interpolymer includes copolymers (usually employed to
refer to polymers prepared from two different monomers) and
polymers prepared from more than two different types of
monomers.
[0017] "Ethylenic polymer" refers to a polymer that contains more
than 50 mole percent polymerized ethylene monomer (based on the
total amount of polymerizable monomers) and, optionally, may
contain one or more comonomers.
[0018] The term "ethylene/.alpha.-olefin interpolymer" refers to an
interpolymer that contains more than 50 mole percent polymerized
ethylene monomer (based on the total amount of polymerizable
monomers) and at least one .alpha.-olefin.
[0019] Test Methods and Measurements
[0020] Density: The density of a polymer (g/cm.sup.3) is measured
according to ASTM-D 792-03, Method B, in isopropanol. Specimens are
measured within 1 hour of molding after conditioning in the
isopropanol bath at 23.degree. C. for 8 min to achieve thermal
equilibrium prior to measurement. The specimens are compression
molded according to ASTM D-4703-00 Annex A with a 5 min initial
heating period at about 190.degree. C. and a 15.degree. C./min
cooling rate per Procedure C. The specimen is cooled to 45.degree.
C. in the press with continued cooling until "cool to the
touch."
[0021] Melt Indices and Melt Index Ratio: The melt index (I.sub.2)
of a polymer is measured in accordance with ASTM D 1238, Condition
190.degree. C./2.16 kg, and is reported in grams eluted per 10
minutes, and the melt index (I.sub.10) is measured in accordance
with ASTM D 1238, Condition 190.degree. C./10 kg, and is reported
in grams eluted per 10 minutes. The melt index ratio
(I.sub.10/I.sub.2) is a ratio of these two melt indices.
[0022] Differential Scanning calorimetry: Differential Scanning
calorimetry (DSC) can be used to measure the melting and
crystallization behavior of a polymer over a wide range of
temperature. For example, the TA Instruments Q1000 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 175.degree. C.; the melted sample is then air-cooled
to room temperature (.about.25.degree. C.). A 3-10 mg, 6 mm
diameter specimen is extracted from the cooled polymer, weighed,
placed in a light aluminum pan (ca 50 mg), and crimped shut.
Analysis is then performed to determine its thermal properties. The
thermal behavior of the sample is determined by ramping the sample
temperature up and down to create a heat flow versus temperature
profile. First, the sample is rapidly heated to 180.degree. C. and
held isothermal for 3 minutes in order to remove its thermal
history. Next, the sample is cooled to -40.degree. C. at a
10.degree. C./minute cooling rate and held isothermal at
-40.degree. C. for 3 minutes. The sample is 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 cool curve is analyzed by setting baseline endpoints
from the beginning of crystallization to -20.degree. C. The heat
curve is analyzed by setting baseline endpoints from -20.degree. C.
to the end of melt. The values determined are peak melting
temperature (T.sub.m), peak crystallization temperature (T.sub.c),
heat of fusion (H.sub.f) (in Joules per gram), and the calculated %
crystallinity for polyethylene samples using:
%Crystallinity=((H.sub.f)/(292 J/g)).times.100.
[0023] The heat of fusion (H.sub.f) and the peak melting
temperature are reported from the second heat curve. Peak
crystallization temperature is determined from the cooling
curve.
[0024] Molecular Weight Measurements by Triple Detector Gel
Permeation Chromatography (3D-GPC)
[0025] The 3D-GPC system consists of a Polymer Laboratories
(Shropshire, UK) Model 210 equipped with an on-board differential
refractometer (RI). Additional detectors can include Precision
Detectors (Amherst, Mass.) 2-angle laser light scattering detector
Model 2040, and a Viscotek (Houston, Tex.) 150R 4-capillary
solution viscometer. The 15-degree angle of the light scattering
detector is used for calculation purposes. Data collection can be
performed using Viscotek TriSEC software, Version 3, and a
4-channel Viscotek Data Manager DM400. The system is also equipped
with an on-line solvent degassing device from Polymer Laboratories
(Shropshire, UK). Suitable high temperature GPC columns such as 30
cm Polymer Labs columns of 10-micron mixed-pore-size packing
(Mixed-B). The sample carousel compartment is operated at
145.degree. C. and the column compartment is operated at
145.degree. C. The samples are prepared at a concentration of 0.025
g of polymer in 20 mL of solvent. The chromatographic solvent
contains 100 ppm and the sample preparation solvent contains 200
ppm of butylated hydroxytoluene (BHT). Both solvents are sparged
with nitrogen. The polyethylene samples are gently shaken every 30
minutes while maintaining 160.degree. C. for 2.5-3.0 hours. The
injection volume is 200 microliters. The flow rate through the GPC
is set at 1 mL/minute.
[0026] The GPC column set is calibrated before running the polymer
by running twenty narrow molecular weight distribution polystyrene
standards. The molecular weight (MW) of the standards ranges from
580 to 8,400,000 g/mol, and the standards are contained in 6
"cocktail" mixtures. Each standard mixture has at least a decade of
separation between individual molecular weights. The standards are
purchased from Polymer Laboratories (Shropshire, UK). The
polystyrene standards are prepared at 0.005 g in 20 mL of solvent
for molecular weights equal to or greater than 1,000,000 g/mol and
0.001 g in 20 mL of solvent for molecular weights less than
1,000,000 g/mol. The polystyrene standards were dissolved at room
temperature with gentle agitation for four hours. The narrow
standards mixtures are run first and in order of decreasing highest
molecular weight component to minimize degradation. A logarithmic
molecular weight calibration is generated using a fifth-order
polynomial fit as a function of elution volume. The absolute
molecular weights were 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, Page 113-136, Elsevier, Oxford, N.Y. (1987)).
The response factor of the laser detector and the viscometer were
determined using the certificated value for the weight average
molecular weight (52,000 g/mol, dn/dc=0.104 mL/g) and intrinsic
viscosity (1.01 dL/g) of NIST 1475. The mass constant of the
differential refractive index detector was determined using the
area under the curve, concentration, and injection volume of the
broad polyethylene homopolymer. The chromatographic concentrations
were assumed low enough to eliminate addressing 2nd Virial
coefficient effects (concentration effects on molecular
weight).
[0027] The Systematic Approach for the determination of each
detector offset was implemented 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)), using data
obtained from the three detectors while analyzing a broad linear
polystyrene homopolymer and the narrow polystyrene standards,
[0028] g'(HMW)/g'(LMW) Determination
[0029] The g' was defined as the ratio of measured intrinsic
viscosity [.eta.] of polymer divided by the intrinsic viscosity
[.eta.].sub.linear of a linear polymer having the same molecular
weight. A value of g' is often used for indication of branching in
a polymer. For the purpose of this invention, g' is defined as the
same comonomer level for the inventive polymer and the linear
polymer.
[0030] A value of g'(HMW)/g'(LMW) is a measure of the branching
level difference between the highest and lowest molecular weight
ranges. For linear polymers, the g'(HMW)/g'(LMW) value equals 1.0
and for branched polymer this value is less than 1.0.
[0031] The g'(HMW)/g'(LMW) value was calculated using 3D-GPC. A
value of g'.sub.1, the g' value at i.sup.th fraction in the polymer
molecular weight distribution was calculated. The polymer molecular
weight distribution curve was normalized and weight fraction at
i.sup.th molecular weight was calculated.
[0032] The g'(HMW) was calculated by the weighted mean value of g'
calculated for the 30% of polymer with highest molecular
weight,
g ' ( HMW ) = i ( g i ' .times. w i ) i w i = i ( g i ' .times. w i
) 0.30 ##EQU00001##
here w.sub.i is the i.sup.th fraction of polymers within the 30% of
polymers with highest molecular weight, and g' is the
[.eta.]/[.eta.].sub.linear value in the same i.sup.th fraction.
[0033] The g'(LMW) was calculated in the same way, where w.sub.i is
the i.sup.th fraction of polymers within the 30% of polymers with
lowest molecular weight.
g ' ( LMW ) = j ( g j ' .times. w j ) j w j = j ( g j ' .times. w j
) 0.3 ##EQU00002##
[0034] Creep Zero Shear Viscosity Method
[0035] Specimens for creep measurements were prepared on a
programmable Tetrahedron bench top press. The program held the melt
at 177.degree. C. for 5 minutes at a pressure of 10.sup.7 Pa. The
chase was then removed to the benchtop to cool down to room
temperature. Round test specimens were then die-cut from the plaque
using a punch press and a handheld die with a diameter of 25 mm.
The specimen is about 1.8 mm thick.
[0036] Zero-shear viscosities are obtained via creep tests that are
conducted on an AR-G2 stress controlled rheometer (TA Instruments;
New Castle, Del.) using 25-mm-diameter parallel plates at
190.degree. C. The rheometer oven is set to test temperature for at
least 30 minutes prior to zeroing fixtures. At the testing
temperature a compression molded sample disk is inserted between
the plates and allowed to come to equilibrium for 5 minutes. The
upper plate is then lowered down to 50 .mu.m above the desired
testing gap (1.5 mm). Any superfluous material is trimmed off and
the upper plate is lowered to the desired gap. Measurements are
done under nitrogen purging at a flow rate of 5 L/min. Default
creep time is set for 2 hours.
[0037] A constant low shear stress of 20 Pa is applied for all of
the samples to ensure that the steady state shear rate is low
enough to be in the Newtonian region. The resulting steady state
shear rates are in the order of 10.sup.-3 s.sup.-1 for the samples
in this study. Steady state is determined by taking a linear
regression for all the data in the last 10% time window of the plot
of log(J(t)) vs. log(t), where J(t) is creep compliance and t is
creep time. If the slope of the linear regression is greater than
0.97, steady state is considered to be reached, then the creep test
is stopped. In all cases in this study the slope meets the
criterion within 30 minutes. The steady state shear rate is
determined from the slope of the linear regression of all of the
data points in the last 10% time window of the plot of .epsilon.
vs. t, where .epsilon. is strain. The zero-shear viscosity is
determined from the ratio of the applied stress to the steady state
shear rate.
[0038] In order to determine if the sample is degraded during the
creep test, a small amplitude oscillatory shear test is conducted
before and after the creep test on the same specimen from 0.1 to
100 rad/s at 10% strain. The complex viscosity values of the two
tests are compared. If the difference of the viscosity values at
0.1 rad/s is greater than 5%, the sample is considered to have
degraded during the creep test, and the result is discarded.
[0039] ZSVR Definition:
[0040] Zero-shear viscosity ratio (ZSVR) is defined as the ratio of
the zero-shear viscosity (ZSV) of the inventive polymer to the ZSV
of a linear polyethylene material at the equivalent weight average
molecular weight (M.sub.w-gpc) as shown in the equation below.
ZSVR = .eta. 0 .eta. 0 L ##EQU00003##
[0041] The .eta..sub.0 value (in Pas) is obtained from creep test
at 190.degree. C. via the method described above. It is known that
ZSV of linear polyethylene .eta..sub.0L has a power law dependence
on its M.sub.w when the M.sub.w is above the critical molecular
weight M.sub.c. An example of such a relationship is described in
Karjala et al. (Annual Technical Conference--Society of Plastics
Engineers (2008), 66.sup.th, 887-891) as shown in the equation
below and it is used in the present invention to calculate the ZSVR
values.
.eta..sub.0L=2.29.times.10.sup.-15M.sub.w-gpc.sup.3.65
[0042] The M.sub.w-gpc value in the equation (in g/mol) is
determined by using the GPC method as defined in the next
section.
[0043] M.sub.w-gpc Determination
[0044] To obtain M.sub.w-gpc values, the chromatographic system
consisted of either a Polymer Laboratories Model PL-210 or a
Polymer Laboratories Model PL-220. The column and carousel
compartments were operated at 140.degree. C. Three Polymer
Laboratories 10-.mu.m Mixed-B columns were used with a solvent of
1,2,4-trichlorobenzene. The samples were prepared at a
concentration of 0.1 g of polymer in 50 mL of solvent. The solvent
used to prepare the samples contained 200 ppm of the antioxidant
butylated hydroxytoluene (BHT). Samples were prepared by agitating
lightly for 4 hours at 160.degree. C. The injection volume used was
100 microliters and the flow rate was 1.0 mL/min. Calibration of
the GPC column set was performed with twenty one narrow molecular
weight distribution polystyrene standards purchased from Polymer
Laboratories. The polystyrene standard peak molecular weights were
converted to polyethylene molecular weights using
M.sub.polyethylene=A(M.sub.polystyrene).sup.B (3)
where M is the molecular weight, A has a value of 0.4316 and B is
equal to 1.0. A third order polynomial was determined to build the
logarithmic molecular weight calibration as a function of elution
volume. Polyethylene equivalent molecular weight calculations were
performed using Viscotek TriSEC software Version 3.0. The precision
of the weight-average molecular weight .DELTA.M.sub.w,2s was
excellent at <2.6%.
Gel Rating of the Polymers.
[0045] Method/Description of GI200 Test
Extruder: Model OCS ME 20 available from OCS Optical Control
Systems GmbH Wullener Feld 36, 58454 Witten, Germany or
equivalent.
TABLE-US-00001 Parameter Standard Screw L/D 25/1 Coating Chrome
Compression ratio 3/1 Feed Zone 10D Transition Zone 3D Metering
Zone 12D Mixing Zone --
Cast Film Die: ribbon die, 150.times.0.5 mm, available from OCS
Optical Control Systems GmbH, or equivalent. Air Knife: OCS air
knife to pin the film on the chill roll, available from OCS Optical
Control Systems GmbH, or equivalent. Cast Film Chill Rolls and
Winding Unit: OCS Model CR-8, available from OCS Optical Control
Systems GmbH, or equivalent.
TABLE-US-00002 Profile Number 070 071 072 MELT INDEX dg/min 0.1-1.2
1.2-3.2 3.2-32 Density g/cm.sup.3 ALL ALL ALL Throat .degree. C. 25
.+-. 3 25 .+-. 3 25 .+-. 3 Zone 1 .degree. C. 180 .+-. 5 160 .+-. 5
140 .+-. 5 Zone 2 .degree. C. 240 .+-. 5 190 .+-. 5 170 .+-. 5 Zone
3 .degree. C. 260 .+-. 5 200 .+-. 5 175 .+-. 5 Zone 4 .degree. C.
260 .+-. 5 210 .+-. 5 175 .+-. 5 Adapter .degree. C. 260 .+-. 5 225
.+-. 5 180 .+-. 5 Die .degree. C. 260 .+-. 5 225 .+-. 5 180 .+-. 5
Screw Type Standard Standard Standard Screw Speed RPM 70 .+-. 2 70
.+-. 2 70 .+-. 2 Air Knife Flow Nm.sup.3/h 6 .+-. 2 6 .+-. 2 6 .+-.
2 Die to Chill Roll mm 6 .+-. 1 6 .+-. 1 6 .+-. 1 Die to Air Knife
mm 6 .+-. 1 6 .+-. 1 6 .+-. 1 Chill Speed m/min. 3 .+-. 1 3 .+-. 1
3 .+-. 1 Chill Temp. .degree. C. 20 .+-. 2 20 .+-. 2 20 .+-. 2
Tension Speed m/min. 6 .+-. 2 6 .+-. 2 6 .+-. 2 Winder Torque N 8
.+-. 1 8 .+-. 1 8 .+-. 1 Lab Temperature .degree. C. 23 .+-. 2 23
.+-. 2 23 .+-. 2 Lab Humidity % <70 <70 <70 Width mm 108
.+-. 18 108 .+-. 18 108 .+-. 18 Thickness .mu.m 76 .+-. 5 76 .+-. 5
76 .+-. 5 Gel Counter: OCS FS-3 line gel counter consisting of a
lighting unit, a CCD detector and an image processor with the Gel
counter software version 3.65e 1991-1999, available from OCS
Optical Control Systems GmbH, or equivalent. The OCS FS-5 gel
counter is equivalent. Instantaneous GI200 Note: GI stands for "gel
index". GI200 includes all gels .gtoreq.200 .mu.m in diameter.
[0046] The instantaneous GI200 is the sum of the area of all the
size classes in one analysis cycle:
X j = k = 1 4 A T , j , k ##EQU00004##
[0047] where:
[0048] X.sub.j=instantaneous GI200 (mm.sup.2/24.6 cm.sup.3) for
analysis cycle j 4=total number of size clauses
GI200
[0049] GI200 is defined as the trailing average of the last twenty
instantaneous G1200 values:
< X >= j = 1 20 X j / 20 ##EQU00005##
where:
<X>=GI200(mm.sup.2/24.6 cm.sup.3)
One analysis cycle inspects 24.6 cm.sup.3 of film. The
corresponding area is 0.324 m.sup.2 for a film thickness of 76
.mu.m and 0.647 m.sup.2 for a film thickness of 38 .mu.m.
[0050] Gel Content Measurement: When the ethylene interpolymer,
either alone or contained in a composition is at least partially
crosslinked, the degree of crosslinking may be measured by
dissolving the composition in a solvent for specified duration, and
calculating the percent gel or unextractable component. The percent
gel normally increases with increasing crosslinking levels.
[0051] Long chain branching per 1000 carbons: The presence of long
chain branching can be determined in ethylene homopolymers by using
.sup.13C nuclear magnetic resonance (NMR) spectroscopy and is
quantified using the method described by Randall (Rev. Macromol.
Chem. Phys., C29, V. 2&3, 285-297). There are other known
techniques useful for determining the presence of long chain
branches in ethylene polymers, including ethylene/1-octene
interpolymers. Two such exemplary methods are gel permeation
chromatography coupled with a low angle laser light scattering
detector (GPC-LALLS) and gel permeation chromatography coupled with
a differential viscometer detector (GPC-DV). The use of these
techniques for long chain branch detection and the underlying
theories have been well documented in the literature. See, for
example, Zimm, G. H. and Stockmayer, W. H., J. Chem. Phys., 17,
1301 (1949), and Rudin, A., Modern Methods of Polymer
Characterization, John Wiley & Sons, New York (1991)
103-112.
[0052] Hot Tack Testing of Films: Hot Tack testing can be
determined in accordance to Strength (Hot Tack) of Thermoplastic
Polymers and Blends Comprising the Sealing Surfaces of Flexible
Webs as referenced in ASTM F-1921.sub.--04.
[0053] Ethylenic polymers of this Invention: The ethylenic polymers
of this invention are relatively high molecular weight, relatively
low density polymers that have a unique combination of (A) a
relatively low total amount of unsaturation, and (B) a relatively
high ratio of vinyl groups to total unsaturated groups in the
polymer chain, as compared to known metallocene-catalyzed ethylenic
polymers. This combination is believed to result in lower gels for
end-use applications (such as films) where low gels are important,
better long-term polymer stability and, for end-use applications
requiring cross-linking, better control of that cross-linking, in
each case while maintaining a good balance of other performance
properties.
[0054] The novel polymers of this invention are interpolymers of
ethylene with at least 0.1 mole percent of one or more comonomers,
preferably at least one .alpha.-olefin comonomer. The
.alpha.-olefin comonomer(s) may have, for example, from 3 to 20
carbon atoms. Preferably, the .alpha.-olefin comonomer may have 3
to 8 carbon atoms. Exemplary .alpha.-olefin comonomers include, but
are not limited to, propylene, 1-butene, 3-methyl-1-butene,
1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,
1-heptene, 4,4-dimethyl-1-pentene, 3-ethyl-1-pentene, 1-octene,
1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,
1-octadecene and 1-eicosene.
[0055] Preparation of an Ethylenic Polymer of this Invention
[0056] For producing the ethylenic polymers of this invention, a
solution-phase polymerization process may be used. Typically, such
a process occurs in a well-stirred reactor such as a loop reactor
or a sphere reactor at temperature from about 150 to about
300.degree. C., preferably from about 160 to about 180.degree. C.,
and at pressures from about 30 to about 1000 psi, preferably from
about 30 to about 750 psi. The residence time in such a process is
typically from about 2 to about 20 minutes, preferably from about
10 to about 20 minutes. Ethylene, solvent, catalyst, and one or
more comonomers are fed continuously to the reactor. Exemplary
solvents include, but are not limited to, isoparaffins. For
example, such solvents are commercially available under the name
ISOPAR E from ExxonMobil Chemical Co., Houston, Tex. The resultant
mixture of ethylene-based polymer and solvent is then removed from
the reactor and the polymer is isolated. Solvent is typically
recovered via a solvent recovery unit, that is, heat exchangers and
vapor liquid separator drum, and is recycled back into the
polymerization system.
[0057] Suitable catalysts for use in preparing the novel polymers
of this invention include any compound or combination of compounds
that is adapted for preparing such polymers in the particular type
of polymerization process, such as solution-polymerization,
slurry-polymerization or gas-phase-polymerization processes.
[0058] In one embodiment, an ethylenic polymer of this invention is
prepared in a solution-polymerization process using a
polymerization catalyst that is a metal complex of a polyvalent
aryloxyether corresponding to the formula:
##STR00001##
[0059] where M.sup.3 is Ti, Hf or Zr, preferably Zr;
[0060] Ar.sup.4+ independently each occurrence is a substituted
C.sub.9-20 aryl group, wherein the substituents, independently each
occurrence, are selected from the group consisting of alkyl;
cycloalkyl; and aryl groups; and halo-, trihydrocarbylsilyl- and
halohydrocarbyl-substituted derivatives thereof, with the proviso
that at least one substituent lacks co-planarity with the aryl
group to which it is attached;
[0061] T.sup.4 independently each occurrence is a C.sub.2-20
alkylene, cycloalkylene or cycloalkenylene group, or an inertly
substituted derivative thereof;
[0062] R.sup.21 independently each occurrence is hydrogen, halo,
hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl,
alkoxy or di(hydrocarbyl)amino group of up to 50 atoms not counting
hydrogen;
[0063] R.sup.3 independently each occurrence is hydrogen, halo,
hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl,
alkoxy or amino of up to 50 atoms not counting hydrogen, or two
R.sup.3 groups on the same arylene ring together or an R.sup.3 and
an R.sup.21 group on the same or different arylene ring together
form a divalent ligand group attached to the arylene group in two
positions or join two different arylene rings together; and
[0064] R.sup.D, independently each occurrence is halo or a
hydrocarbyl or trihydrocarbylsilyl group of up to 20 atoms not
counting hydrogen, or 2 R.sup.D groups together are a
hydrocarbylene, hydrocarbadiyl, diene, or poly(hydrocarbyl)silylene
group.
[0065] Such polyvalent aryloxyether metal complexes and their
synthesis are described in WO 2007/136496 or WO 2007/136497, using
the synthesis procedures disclosed in US-A-2004/0010103. Among the
preferred polyvalent aryloxyether metal complexes are those
disclosed as example 1 in WO 2007/136496 and as example A10 in WO
2007/136497. Suitable cocatalysts and polymerization conditions for
use of the preferred polyvalent aryloxyether metal complexes are
also disclosed in WO 2007/136496 or WO 2007/136497.
[0066] The metal complex polymerization catalyst may be activated
to form an active catalyst composition by combination with one or
more cocatalysts, preferably a cation forming cocatalyst, a strong
Lewis acid, or a combination thereof. Suitable cocatalysts for use
include polymeric or oligomeric aluminoxanes, especially methyl
aluminoxane, as well as inert, compatible, noncoordinating, ion
forming compounds. So-called modified methyl aluminoxane (MMAO) or
triethyl aluminum (TEA) is also suitable for use as a cocatalyst.
One technique for preparing such modified aluminoxane is disclosed
in U.S. Pat. No. 5,041,584 (Crapo et al.). Aluminoxanes can also be
made as disclosed in U.S. Pat. Nos. 5,542,199 (Lai et al.);
4,544,762 (Kaminsky et al.); 5,015,749 (Schmidt et al.); and
5,041,585 (Deavenport et al.).
[0067] Polymeric Blends or Compounds of this invention: Various
natural or synthetic polymers, and/or other components, may be
blended or compounded with the novel polymers of this invention to
form the polymeric compositions of this invention. Suitable
polymers for blending with the embodiment ethylenic polymer include
thermoplastic and non-thermoplastic polymers including natural and
synthetic polymers. Suitable synthetic polymers include both
ethylene-based polymers, such as high pressure, free-radical low
density polyethylene (LDPE), and ethylene-based polymers prepared
with Ziegler-Natta catalysts, including high density polyethylene
(HDPE) and heterogeneous linear low density polyethylene (LLDPE),
ultra low density polyethylene (ULDPE), and very low density
polyethylene (VLDPE), as well as multiple-reactor ethylenic
polymers ("in reactor" blends of Ziegler-Natta PE and metallocene
PE, such as products disclosed in U.S. Pat. Nos. 6,545,088
(Kolthammer et al.); 6,538,070 (Cardwell et al.); 6,566,446 (Parikh
et al.); 5,844,045 (Kolthammer et al.); 5,869,575 (Kolthammer et
al.); and 6,448,341 (Kolthammer et al.)). Commercial examples of
linear ethylene-based polymers include ATTANE.TM. Ultra Low Density
Linear Polyethylene Copolymer, DOWLEX.TM. Polyethylene Resins, and
FLEXOMER.TM. Very Low Density Polyethylene, all available from The
Dow Chemical Company. Other suitable synthetic polymers include
polypropylene, (both impact modifying polypropylene, isotactic
polypropylene, atactic polypropylene, and random ethylene/propylene
copolymers), ethylene/diene interpolymers, ethylene-vinyl acetate
(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 olefin-based polymers such as
ethylene-based or propylene-based plastomers or elastomers can also
be useful as components in blends or compounds made with the
ethylenic polymers of this invention. Commercial examples of
homogeneous metallocene-catalyzed, ethylene-based plastomers or
elastomers include AFFINITY.TM. polyolefin plastomers and
ENGAGE.TM. polyolefin elastomers, both available from The Dow
Chemical Company, and commercial examples of homogeneous
propylene-based plastomers and elastomers include VERSIFY.TM.
performance polymers, available from The Dow Chemical Company, and
VISTAMAX.TM. polymers available from ExxonMobil Chemical
Company.
[0068] The polymeric compositions of this invention include
compositions comprising, or made from, the ethylenic polymer of
this invention in combination (such as blends or compounds,
including reaction products) with one or more other components,
which other components may include, but are not limited to, natural
or synthetic materials, polymers, additives, reinforcing agents,
ignition resistant additives, fillers, waxes, tackifiers,
antioxidants, stabilizers, colorants, extenders, crosslinkers,
blowing agents, and/or plasticizers. Such polymeric compositions
may include thermoplastic polyolefins (TPO), thermoplastic
elastomers (TPE), thermoplastic vulcanizates (TPV) and/or
styrenic/ethylenic polymer blends. TPEs and TPVs may be prepared by
blending or compounding one or more ethylenic polymers of this
invention (including functionalized derivatives thereof) with an
optional elastomer (including conventional block copolymers,
especially an SBS or SEBS block copolymer, or EPDM, or a natural
rubber) and optionally a crosslinking or vulcanizing agent. A TPO
polymeric composition of this invention would be prepared by
blending or compounding one or more of the ethylenic polymers of
this invention with one or more polyolefins (such as
polypropylene). A TPE polymeric composition of this invention would
be prepared by blending or compounding one or more of the ethylenic
polymers of this invention with one or more elastomers (such as a
styrenic block copolymer or an olefin block copolymer, such as
disclosed in U.S. Pat. No. 7,355,089 (Chang et al.)). A TPV
polymeric composition of this invention would be prepared by
blending or compounding one or more of the ethylenic polymers of
this invention with one or more other polymers and a vulcanizing
agent.
[0069] The foregoing polymeric compositions may be used in forming
a molded object, and optionally crosslinking the resulting molded
article. A similar procedure using different components has been
previously disclosed in U.S. Pat. No. 6,797,779 (Ajbani, et
al.).
[0070] Processing Aids: In certain aspects of the invention,
processing aids, such as plasticizers, can also be included in the
polymeric composition. These aids include, but are not limited to,
the phthalates (such as dioctyl phthalate and diisobutyl
phthalate), natural oils (such as lanolin, and paraffin, naphthenic
and aromatic oils obtained from petroleum refining), and liquid
resins from rosin or petroleum feedstocks. Exemplary classes of
oils useful as processing aids include white mineral oil such as
KAYDOL.RTM. oil (Chemtura Corp.; Middlebury, Conn.) and
SHELLFLEX.RTM. 371 naphthenic oil (Shell Lubricants; Houston,
Tex.). Another suitable oil is TUFFLO.RTM. oil (Lyondell
Lubricants; Houston, Tex.).
[0071] Stabilizers and other additives: In certain aspects of the
invention, the ethylenic polymers are treated with one or more
stabilizers, for example, antioxidants, such as IRGANOX.RTM. 1010
and IRGAFOS.RTM. 168 (Ciba Specialty Chemicals; Glattbrugg,
Switzerland). In general, polymers are treated with one or more
stabilizers before an extrusion or other melt processes. For
example, the compounded polymeric composition may comprise from 200
to 600 wppm of one or more phenolic antioxidants, and/or from 800
to 1200 wppm of a phosphite-based antioxidant, and/or from 300 to
1250 wppm of calcium stearate. In other aspects of the invention,
other polymeric additives are blended or compounded into the
polymeric compositions, such as ultraviolet light absorbers,
antistatic agents, pigments, dyes, nucleating agents, fillers, slip
agents, fire retardants, plasticizers, processing aids, lubricants,
stabilizers, smoke inhibitors, viscosity control agents, and/or
anti-blocking agents. The polymeric composition may, for example,
comprise less than 10 percent by the combined weight of one or more
of such additives, based on the weight of the ethylenic
polymer.
[0072] Other additives: Various other additives and adjuvants may
be blended or compounded with the ethylenic polymers of this
invention to form polymeric compositions, including fillers (such
as organic or inorganic particles, including nano-size particles,
such as clays, talc, titanium dioxide, zeolites, powdered metals),
organic or inorganic fibers (including carbon fibers, silicon
nitride fibers, steel wire or mesh, and nylon or polyester
cording), tackifiers, waxes, and oil extenders (including
paraffinic or naphthelenic oils), sometimes in combination with
other natural and/or synthetic polymers.
[0073] Cross-linking Agents: For those end-use applications in
which it is desired to fully or partially cross-link the ethylenic
polymer of this invention, any of a variety of cross-linking agents
may be used. Some suitable cross-linking agents are disclosed in
Zweifel Hans et al., "Plastics Additives Handbook," Hanser Gardner
Publications, Cincinnati, Ohio, 5th edition, Chapter 14, pages
725-812 (2001); Encyclopedia of Chemical Technology, Vol. 17, 2nd
edition, Interscience Publishers (1968); and Daniel Seem, "Organic
Peroxides," Vol. 1, Wiley-Interscience, (1970). Non-limiting
examples of suitable cross-linking agents include peroxides,
phenols, azides, aldehyde-amine reaction products, substituted
ureas, substituted guanidines; substituted xanthates; substituted
dithiocarbamates; sulfur-containing compounds, such as thiazoles,
sulfenamides, thiuramidisulfides, paraquinonedioxime,
dibenzoparaquinonedioxime, sulfur; imidazoles; silanes and
combinations thereof. Non-limiting examples of suitable organic
peroxide cross-linking agents include alkyl peroxides, aryl
peroxides, peroxyesters, peroxycarbonates, diacylperoxides,
peroxyketals, cyclic peroxides and combinations thereof. In some
embodiments, the organic peroxide is dicumyl peroxide,
t-butylisopropylidene peroxybenzene, 1,1-di-t-butyl
peroxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butyl
peroxy)hexane, t-butyl-cumyl peroxide, di-t-butyl peroxide,
2,5-dimethyl-2,5-di-(t-butyl peroxy)hexyne or a combination
thereof. In one embodiment, the organic peroxide is dicumyl
peroxide. Additional teachings regarding organic peroxide
cross-linking agents are disclosed in C. P. Park, "Polyolefin
Foam", Chapter 9 of Handbook of Polymer Foams and Technology,
edited by D. Klempner and K. C. Frisch, Hanser Publishers, pp.
198-204, Munich (1991). Non-limiting examples of suitable azide
cross-linking agents include azidoformates, such as
tetramethylenebis(azidoformate); aromatic polyazides, such as
4,4'-diphenylmethane diazide; and sulfonazides, such as
p,p'-oxybis(benzene sulfonyl azide). The disclosure of azide
cross-linking agents can be found in U.S. Pat. Nos. 3,284,421 and
3,297,674. In some embodiments, the cross-linking agents are
silanes. Any silane that can effectively graft to and/or cross-link
the ethylene/.alpha.-olefin interpolymer or the polymer blend
disclosed herein can be used. Non-limiting examples of suitable
silane cross-linking agents include unsaturated silanes that
comprise an ethylenically unsaturated hydrocarbyl group, such as a
vinyl, allyl, isopropenyl, butenyl, cyclohexenyl or
gamma-(meth)acryloxy allyl group, and a hydrolyzable group such as
a hydrocarbyloxy, hydrocarbonyloxy, and hydrocarbylamino group.
Non-limiting examples of suitable hydrolyzable groups include
methoxy, ethoxy, formyloxy, acetoxy, proprionyloxy, alkyl and
arylamino groups. In other embodiments, the silanes are the
unsaturated alkoxy silanes which can be grafted onto the
interpolymer. Some of these silanes and their preparation methods
are more fully described in U.S. Pat. No. 5,266,627. The amount of
the cross-linking agent can vary widely, depending upon the nature
of the ethylenic polymer or the polymeric composition to be
cross-linked, the particular cross-linking agent employed, the
processing conditions, the amount of grafting initiator, the
ultimate application, and other factors. For example, when
vinyltrimethoxysilane (VTMOS) is used, the amount of VTMOS is
generally at least about 0.1 weight percent, at least about 0.5
weight percent, or at least about 1 weight percent, based on the
combined weight of the cross-linking agent and the ethylenic
polymer or the polymeric composition.
[0074] End Use Applications: The ethylenic polymer of this
invention may be employed in a variety of conventional
thermoplastic fabrication processes to produce useful articles,
including objects comprising at least one film layer, such as a
monolayer film, or at least one layer in a multilayer film, which
films may be prepared by cast, blown, calendered, or extrusion
coating processes; molded articles, such as blow molded, injection
molded, or rotomolded articles; extrusions; fibers; woven or
non-woven fabrics; and composite or laminate structures made with
any of the foregoing articles.
[0075] The ethylenic polymers of this invention (either alone or in
blends or compounds with other components) may be used in producing
fibers, such as staple fibers, tow, multicomponent, sheath/core,
twisted, and monofilament fibers. Suitable fiber-forming processes
include spunbonded and melt blown techniques, as disclosed in U.S.
Pat. Nos. 4,340,563 (Appel et al.), 4,663,220 (Wisneski et al.),
4,668,566 (Nohr et al.), and 4,322,027 (Reba), gel spun fibers as
disclosed in U.S. Pat. No. 4,413,110 (Kavesh et al.), woven and
nonwoven fabrics, as disclosed in U.S. Pat. No. 3,485,706 (May), or
structures made from or with such fibers, including blends with
other fibers (such as polyester, nylon or cotton, and drawn,
twisted, or crimped yarns or fibers) or in composition or laminated
structures with fibrous or non-fibrous materials (such as nonwovens
or films).
[0076] The ethylenic polymers of this invention (either alone or in
blends or compounds with other components) may be used in a variety
of films, including but not limited to clarity shrink films,
collation shrink films, cast stretch films, silage films, stretch
hooder films, sealants (including heat sealing films),
stand-up-pouch films, liner films, and diaper backsheets.
[0077] The ethylenic polymers are especially useful for making
films or film layers, preferably wherein the film or film layer is
subsequently heat sealed to form a thermally welded bond. The
ethylenic polymers preferably have a peak hot tack in (N/inch) is
greater than or equal to the quantity (13-0.395*12) at a seal bar
temperature of from 90 to 140 C.
[0078] The ethylenic polymers of this invention (either alone or in
blends or compounds with other components) are also useful in other
direct end-use applications, such as for wire and cable coatings,
in sheet extrusion for vacuum forming operations, and forming
molded articles, including articles made via any of the known
thermoplastic molding technologies, including injection molding,
blow molding, or rotomolding processes. The polymeric compositions
of this invention can also be formed into fabricated articles using
other conventional polyolefin processing techniques.
[0079] Other suitable applications for the ethylenic polymers of
this invention (either alone or in blends or compounds with other
components) include films and fibers; soft touch goods, such as
tooth brush handles and appliance handles; gaskets and profiles;
adhesives (including hot melt adhesives and pressure sensitive
adhesives); footwear (including shoe soles and shoe liners); auto
interior or exterior parts and profiles; foam goods (both open and
closed cell); impact modifiers for other thermoplastic polymers
such as high density polyethylene, isotactic polypropylene, or
other olefin polymers; coated fabrics (such as artificial leather);
hoses; tubing; weather stripping; cap liners; flooring (such as
hard or soft flooring and artificial turf); and viscosity index
modifiers, as well as pour point modifiers, for lubricants.
[0080] Further treatment of the ethylenic polymers or polymeric
compositions of this invention may be performed to render them more
suitable for other end uses. For example, dispersions (both aqueous
and non-aqueous) can also be formed using ethylenic polymers or
polymeric compositions of this invention, such as by a
dispersion-manufacturing process. Frothed foams comprising the
embodiment ethylenic polymer can also be formed, as disclosed in
PCT Publication No. 2005/021622. The ethylenic polymers or
polymeric compositions of this invention may also be crosslinked by
any known means, such as the use of peroxide, electron beam,
silane, azide, or other cross-linking technique. The ethylenic
polymers or polymeric compositions of this invention can also be
chemically modified, such as by grafting (for example by use of
maleic anhydride (MAH), silanes, or other grafting agent),
halogenation, amination, sulfonation, or other chemical
modification.
[0081] All applications, publications, patents, test procedures,
and other documents cited, including priority documents, are fully
incorporated by reference to the extent such disclosure is not
inconsistent with the disclosed compositions and methods and for
all jurisdictions in which such incorporation is permitted.
Examples
Resin Production
[0082] All raw materials (ethylene, 1-octene) and the process
solvent (a narrow boiling range high-purity isoparaffinic solvent
trademarked Isopar E and commercially available from Exxon Mobil
Corporation) are purified with molecular sieves before introduction
into the reaction environment. Hydrogen is supplied in pressurized
cylinders as a high purity grade and is not further purified. The
reactor monomer feed (ethylene) stream is pressurized via
mechanical compressor to above reaction pressure at 525 psig. The
solvent and comonomer (1-octene) feed is pressurized via mechanical
positive displacement pump to above reaction pressure at 525 psig.
The individual catalyst components are manually batch diluted to
specified component concentrations with purified solvent (Isopar E)
and pressured to above reaction pressure at 525 psig. All reaction
feed flows are measured with mass flow meters and independently
controlled with computer automated valve control systems.
[0083] The continuous solution polymerization reactor consists of a
liquid full, non-adiabatic, isothermal, circulating, and
independently controlled loop. The reactor has independent control
of all fresh solvent, monomer, comonomer, hydrogen, and catalyst
component feeds. The combined solvent, monomer, comonomer and
hydrogen feed to the reactor is temperature controlled to anywhere
between 5.degree. C. to 50.degree. C. and typically 25.degree. C.
by passing the feed stream through a heat exchanger. The fresh
comonomer feed to the polymerization reactor is fed in with the
solvent feed. The total fresh feed to each polymerization reactor
is injected into the reactor at two locations with roughly equal
reactor volumes between each injection location. The fresh feed is
controlled typically with each injector receiving half of the total
fresh feed mass flow. The catalyst components are injected into the
polymerization reactor through specially designed injection
stingers and are each separately injected into the same relative
location in the reactor with no contact time prior to the reactor.
The primary catalyst component feed is computer controlled to
maintain the reactor monomer concentration at a specified target.
The two cocatalyst components are fed based on calculated specified
molar ratios to the primary catalyst component. Immediately
following each fresh injection location (either feed or catalyst),
the feed streams are mixed with the circulating polymerization
reactor contents with Kenics static mixing elements. The contents
of each reactor are continuously circulated through heat exchangers
responsible for removing much of the heat of reaction and with the
temperature of the coolant side responsible for maintaining
isothermal reaction environment at the specified temperature.
Circulation around each reactor loop is provided by a screw
pump.
[0084] The effluent from the first polymerization reactor
(containing solvent, monomer, comonomer, hydrogen, catalyst
components, and molten polymer) exits the first reactor loop and
passes through a control valve (responsible for maintaining the
pressure of the first reactor at a specified target). As the stream
exits the reactor it is contacted with water to stop the reaction.
In addition, various additives such as anti-oxidants, can be added
at this point. The stream then goes through another set of Kenics
static mixing elements to evenly disperse the catalyst kill and
additives.
[0085] Following additive addition, the effluent (containing
solvent, monomer, comonomer, hydrogen, catalyst components, and
molten polymer) passes through a heat exchanger to raise the stream
temperature in preparation for separation of the polymer from the
other lower boiling reaction components. The stream then enters a
two stage separation and devolatization system where the polymer is
removed from the solvent, hydrogen, and unreacted monomer and
comonomer. The recycled stream is purified before entering the
reactor again. The separated and devolatized polymer melt is pumped
through a die specially designed for underwater pelletization, cut
into uniform solid pellets, dried, and transferred into a hopper.
After validation of initial polymer properties the solid polymer
pellets are manually dumped into a box for storage. Each box
typically holds .about.1200 pounds of polymer pellets.
[0086] The non-polymer portions removed in the devolatilization
step pass through various pieces of equipment which separate most
of the ethylene which is removed from the system to a vent
destruction unit (it is recycled in manufacturing units). Most of
the solvent is recycled back to the reactor after passing through
purification beds. This solvent can still have unreacted co-monomer
in it that is fortified with fresh co-monomer prior to re-entry to
the reactor. This fortification of the co-monomer is an essential
part of the product density control method. This recycle solvent
can still have some hydrogen which is then fortified with fresh
hydrogen to achieve the polymer molecular weight target. A very
small amount of solvent leaves the system as a co-product due to
solvent carrier in the catalyst streams and a small amount of
solvent that is part of commercial grade co-monomers.
[0087] Unless otherwise stated, implicit from the context or
conventional in the art, all parts and percentages are based on
weight.
[0088] Comparative Sample E and Examples 6 and 7: Ethylenic
polymers are prepared in order to compare the properties of
ethylene-octene polymers (Comparative Example E) prepared using a
known metallocene catalyst to the properties of ethylene-octene
polymers (Examples 6 and 7) of this invention. Each ethylenic
polymer is prepared in plant operating substantially in accordance
with the resin production section above.
Table 1 describes the polymerization conditions used to produce
each of the copolymers. Table 2 lists various properties of those
polymers.
TABLE-US-00003 TABLE 1 Reactor C.sub.2 Corrected Reactor H.sub.2
Octene/ MI Temp Solvent/ Conv Exit C2 Poly Conc. Mole Olefin Run
Example Catalyst (I.sub.2) Density (C.) C2 Ratio (%) (g/L) (Wt %).
% Ratio Lot Comp E 1301/RIBS2/MMAO 0.98 0.901 XB1401E132 2009C03R09
6 6114/RIBS2/MMAO 1.13 0.900 120.9 4.49 86.5 15.2 19.31 1.075 40.98
2009C03R09 7 6114/RIBS2/MMAO 0.98 0.897 138.7 4.51 85.9 16.2 19.2
0.459 40.98 140 C. CAS name for RIBS-2: Amines, bis(hydrogenated
tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(1-) CAS name
for DOC-6114: Zirconium,
[2,2'''-[1,3-propanediylbis(oxy-.kappa.O)]bis[3'',5,5''-tris(1,1-dimethyl-
ethyl)-5'-methyl[1,1':3',1''-terphenyl]-2'-olato-.kappa.O]]dimethyl-,
(OC-6-33)- MMAO = modified methyl aluminoxane CAS name for CGC
1301:
TABLE-US-00004 TABLE 2 Melt Flow Zero Shear DSC Ratio Viscosity ZSV
Melting g' (HMW)/ Example Catalyst I10/I2 Mw Mn Mw/Mn Pa-s 190 C.
Ratio point (C.) g' (LMW) Comp E 1301/RIBS2/MMAO 9.1 89760 36740
2.44 13029 4.75 98.5 0.950 6 6114/RIBS2/MMAO 6.3 99620 44540 2.24
7610 1.89 96.4 7 1301/RIBS2/MMAO 6.4 103100 47080 2.19 8776 1.93
98.9 0.967
The film-fabrication conditions are described in Table 3.
TABLE-US-00005 TABLE 3 Sample ID EXAMPLE 6 Inventive Comparative E
Comparative Run Number 09C03R09 XB1401E132 Coex Coex B--ATTANE
B--ATTANE A--Example 6 4201/AMPLIFY C--Ultramid A--Comparative
4201/AMPLIFY C--Ultramid w/DOC 6114 GR-205, 90/10 C33L01 Ex. E
GR-205, 90/10 C33LO1 Melt Temperature C. 184 225 185 226 Screw
Speed rpm 66 72 49 66 72 49 Motor Amps A 4.8 6.5 2.2 4.1 6.3 2.2
Melt Back Pressure bar 283 346 101 247 339 99 Feed Rate kg/h 2.8
6.8 3.1 3 6 3 Sample ID Example 7 Inventive Run Number 09C03R09
140.degree. C. Coex B--ATTANE A--Example 7 4201/AMPLIFY C--Ultramid
w/DOC-6114 GR-205, 90/10 C33L01 Melt Temperature C. 185 225 Screw
Speed rpm 66 72 49 Motor Amps A 4.9 6.9 2.3 Melt Back Pressure bar
306 374 103 Feed Rate kg/h 2.7 6 3.1 Film Structure Outer Layer C
Core B Sealant A
TABLE-US-00006 TABLE 4 Hot Tack data that is in graph above.
Example 60 C. 70 C. 80 C. 90 C. 100 C. 110 C. 120 C. 130 C. 140 C.
150 C. Comp. E 0.242 0.356 2.34 5.49 10.12 8.71 8.97 7.78 8.79
12.42 6 0.264 0.604 1.59 4.67 15.86 16.71 11.90 12.70 11.75 5.81 7
0.258 0.276 1.08 3.51 13.03 15.52 12.92 12.12 11.70 9.00
[0089] Comparative Sample E and Examples 6 and 7: Three ethylenic
polymers are prepared in order to compare the hot tack strength and
sealing window properties of a ethylene-octene polymer (Comparative
Samples E) prepared using a known constrained geometry metallocene
catalyst to the properties of two ethylene-octene polymers
(Examples 6 and 7) of this invention when fabricated into a sealant
layer in a multilayer film. Each ethylenic polymer is prepared in
the same pilot plant as described above for Examples 1 through
5.
[0090] The polymers of Comparative Sample E and of Examples 6 and 7
are then fabricated into sealant-layer A of a three-layer film of
the structure A/B/C. Layers B and C are the same for each case,
with layer B comprising a 90/10 blend of ATTANE.TM. ULDPE polymer
with AMPLIFY.TM. GR 205 functionalized polymer (both available from
The Dow Chemical Company), and layer C comprising ULTRAMID.RTM. C
33L 01 polyamide made by BASF Corporation is a Nylon 66/6
(Polyamide 66/6 Copolymer) plastic material.
* * * * *