U.S. patent application number 15/320765 was filed with the patent office on 2017-06-01 for breathable films and articles incorporating same.
The applicant listed for this patent is Dow Global Technologies LLC. Invention is credited to Selim Bensason, Joseph L. Deavenport, Jacquelyn A. Degroot, Mehmet Demirors, Suzanne M. Guerra, Pradeep Jain, Satyajeet Ojha, Rajen M. Patel, Viraj Shah, Jian Wang.
Application Number | 20170152377 15/320765 |
Document ID | / |
Family ID | 53514431 |
Filed Date | 2017-06-01 |
United States Patent
Application |
20170152377 |
Kind Code |
A1 |
Wang; Jian ; et al. |
June 1, 2017 |
BREATHABLE FILMS AND ARTICLES INCORPORATING SAME
Abstract
Breathable films formed from polyethylene are provided that can
have desirable properties. In one aspect, a breathable film
comprises a layer formed from a composition comprising a first
composition, wherein the first composition comprises at least one
ethylene-based polymer and wherein the first composition comprises
a MWCDI value greater than 0.9, and a melt index ratio (I10/I2)
that meets the following equation:
I10/I2.gtoreq.7.0-1.2.times.log(I2).
Inventors: |
Wang; Jian; (Freeport,
TX) ; Jain; Pradeep; (Lake Jackson, TX) ;
Demirors; Mehmet; (Freeport, TX) ; Patel; Rajen
M.; (Freeport, TX) ; Deavenport; Joseph L.;
(Freeport, TX) ; Degroot; Jacquelyn A.; (Freeport,
TX) ; Guerra; Suzanne M.; (Lake Jackson, TX) ;
Shah; Viraj; (Freeport, TX) ; Bensason; Selim;
(Horgen, CH) ; Ojha; Satyajeet; (Dublin,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC |
Midland |
MI |
US |
|
|
Family ID: |
53514431 |
Appl. No.: |
15/320765 |
Filed: |
June 26, 2014 |
PCT Filed: |
June 26, 2014 |
PCT NO: |
PCT/US2015/037870 |
371 Date: |
December 21, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62017525 |
Jun 26, 2014 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 5/00 20130101; B32B
7/00 20130101; C08J 2323/08 20130101; C08K 3/26 20130101; B32B
27/18 20130101; C08J 5/00 20130101; C08L 2205/16 20130101; B32B
2307/544 20130101; C08F 2500/18 20130101; C08J 2423/08 20130101;
C08L 2203/12 20130101; B32B 5/022 20130101; B32B 27/30 20130101;
B32B 2255/00 20130101; B32B 27/08 20130101; B32B 27/12 20130101;
B32B 27/28 20130101; C08J 5/18 20130101; B32B 27/308 20130101; B32B
27/325 20130101; C08L 2314/02 20130101; A61F 13/51401 20130101;
A61F 2013/51409 20130101; B32B 2270/00 20130101; A61F 13/51458
20130101; B32B 27/20 20130101; B32B 2555/00 20130101; B32B 5/02
20130101; B32B 2262/0253 20130101; C08L 2205/025 20130101; B32B
2255/02 20130101; C08L 23/0807 20130101; B32B 7/02 20130101; C08F
2500/11 20130101; B32B 2307/718 20130101; B32B 2262/02 20130101;
B32B 2307/50 20130101; E01C 13/08 20130101; B32B 2307/724 20130101;
C08F 210/16 20130101; B32B 2262/00 20130101; B32B 27/06 20130101;
C08L 23/0815 20130101; C08F 2500/12 20130101; C08J 2323/06
20130101; B32B 2307/726 20130101; B32B 27/306 20130101; B32B 27/32
20130101; B32B 2307/514 20130101; C08K 2003/265 20130101; C08L
2314/06 20130101; C08F 210/16 20130101; C08F 4/64193 20130101; C08F
4/6555 20130101; C08F 210/16 20130101; C08F 2/06 20130101; C08F
210/16 20130101; C08F 2500/10 20130101; C08F 2500/12 20130101; C08F
2500/19 20130101; C08L 23/0815 20130101; C08L 2314/02 20130101;
C08L 2314/06 20130101; C08L 23/0807 20130101; C08L 2314/02
20130101; C08L 2314/06 20130101 |
International
Class: |
C08L 23/08 20060101
C08L023/08; B32B 27/12 20060101 B32B027/12; A61F 13/514 20060101
A61F013/514; B32B 27/08 20060101 B32B027/08; B32B 27/20 20060101
B32B027/20; C08K 3/26 20060101 C08K003/26; B32B 5/02 20060101
B32B005/02; B32B 27/32 20060101 B32B027/32 |
Claims
1. A breathable film comprising a first composition, wherein the
first composition comprises at least one ethylene-based polymer and
wherein the first composition comprises a MWCDI value greater than
0.9, and a melt index ratio (I10/I2) that meets the following
equation: I10/I2.gtoreq.7.0-1.2.times.log(I2).
2. The breathable film of claim 1, wherein the breathable film
further comprises 40 to 65 weight percent of a mineral filler.
3. The breathable film of claim 1, wherein the first composition
has a MWCDI value less than, or equal to, 10.0.
4. The breathable film of claim 1, wherein the first composition
has a density of 0.910 to 0.940 g/cm.sup.3 and a melt index (I2) of
0.5 to 30 g/10 minutes.
5. The breathable film of claim 1, wherein the film has a basis
weight of 10 to 20 g/m.sup.2.
6. The breathable film of claim 1, further comprising a second
polymer, and wherein the second polymer is selected from the
following: a LLDPE, a VLDPE, a LDPE, a MDPE, a HDPE, a HMWHDPE, a
propylene-based polymer, a polyolefin plastomer, a polyolefin
elastomer, an olefin block copolymer, an ethylene vinyl acetate, an
ethylene acrylic acid, an ethylene methacrylic acid, an ethylene
methyl acrylate, an ethylene ethyl acrylate, an ethylene butyl
acrylate, a polyisobutylene, a maleic anhydride-grafted polyolefin,
an ionomer of any of the foregoing, or a combination thereof.
7. The breathable film of claim 1, wherein the breathable film
comprises a first layer comprising the first composition, and a
second layer, wherein the second layer comprises a polymer selected
from the following: the first composition, a LLDPE, a VLDPE, a
LDPE, a MDPE, a HDPE, a HMWHDPE, a propylene-based polymer, a
polyolefin plastomer, a polyolefin elastomer, an olefin block
copolymer, an ethylene vinyl acetate, an ethylene acrylic acid, an
ethylene methacrylic acid, an ethylene methyl acrylate, an ethylene
ethyl acrylate, an ethylene butyl acrylate, a polyisobutylene, a
maleic anhydride-grafted polyolefin, an ionomer of any of the
foregoing, or a combination thereof.
8. The breathable film of claim 1, wherein the breathable film
comprises at least 30 weight percent of the first composition.
9. The breathable film of claim 1, wherein the breathable film
exhibits a water vapor transmission rate of at least 500
g/m.sup.2-day-atm and up to 10,000 g/m.sup.2-day-atm.
10. The breathable film of claim 1, wherein the breathable film is
oriented in at least one of the machine direction and the cross
direction.
11. The breathable film of claim 1, wherein the breathable film is
oriented in the machine direction and the cross direction.
12. A laminate comprising the breathable film of claim 1.
13. The laminate of claim 12, further comprising a non-woven
material.
14. An article comprising the laminate of claim 12.
15. An article comprising the breathable film of claim 1.
Description
FIELD
[0001] The present invention relates generally to breathable films
and to articles incorporating breathable films.
INTRODUCTION
[0002] Breathable films are widely used in hygiene applications
such as diaper backsheets. Persons of skill in the art generally
understand breathable films to have a microporous morphology with
some ability to allow the passage of moisture vapor. See, e.g., Wu
et al., "Novel Microporous Films and Their Composites," Journal of
Engineered Fibers and Fabrics, Vol. 2, Issue 1, at 49-59
(2007).
[0003] Breathable films are typically made by incorporating 40 to
60% of a mineral filler, such as calcium carbonate (CaCO.sub.3),
into polyolefin resin, such as polyethylene or polypropylene or
combinations of these materials, making a cast or blown film, and
stretching or orienting the cast or blown film via machine
direction orientation ("MDO") rolls, via tentering, or via
intermeshing gears whereby the film is ringrolled, or incrementally
stretched in one or both of the machine direction or cross
direction below the melting point of the polyolefin resin. The
breathability or water vapor transmission rate (WVTR) of the film
is important for some applications, such as diaper backsheet films,
protective clothing, surgical suits, and housewrap. In these
applications, films can act as a liquid barrier while permitting
the transmission of water vapor to provide benefits such as
protection and comfort to the end-user in the case of hygiene and
medical applications and protection from the elements without the
accumulation of moisture in the case of housewrap.
[0004] For diaper backsheet applications, breathable films need a
good balance of processability, stiffness and toughness.
Processability, in terms of draw down capability, is needed during
the extrusion and semi-solid state stretching steps of the process
to ensure good, uniform draw down without breaks. Stiffness, often
measured as film modulus, enables good dimension stability for
films as they go through the high speed film printing and diaper
making processes. This ultimately provides staple print repeat
lengths and predictable web widths. Toughness is needed to prevent
film puncture due to the presence of super absorbent polymer (SAP)
particles in the absorbent core next to the film and to prevent
leakers formed by hydrohead pressure due to a saturated absorbent
core and the weight of the end-user.
[0005] While ethylene-based polymers have been used for breathable
films, there remains a need for ethylene-based compositions that
can be used in the manufacture of breathable films having desirable
properties and related articles.
SUMMARY
[0006] The present invention utilizes ethylene-based polymers
exhibiting certain features in the formation of breathable films
with desirable properties. For example, in some embodiments, the
breathable films provide desirable processability, stiffness,
toughness, and/or WVTR values for hygiene and other
applications.
[0007] In one aspect, the present invention provides a breathable
film comprising a layer formed from a composition comprising a
first composition, wherein the first composition comprises at least
one ethylene-based polymer and wherein the first composition
comprises a MWCDI value greater than 0.9, and a melt index ratio
(I10/I2) that meets the following equation:
I10/I2>7.0-1.2.times.log(I2).
[0008] These and other embodiments are described in more detail in
the Detailed Description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 depicts the plot of "SCB.sub.f versus IR5 Area Ratio"
for ten SCB Standards.
[0010] FIG. 2 depicts the several GPC profiles for the
determination of IR5 Height Ratio for Inventive First Composition
2.
[0011] FIG. 3 depicts the plot of "SCB.sub.f versus Polyethylene
Equivalent molecular Log Mw.sub.i (GPC)" for Inventive First
Composition 2.
[0012] FIG. 4 depicts a plot of the "Mole Percent Comonomer versus
Polyethylene Equivalent Log.sub.Mwi (GPC)" for Inventive First
Composition 2.
[0013] FIG. 5 depicts some GPC MWD profiles and corresponding
comonomer distribution overlays for some inventive and comparative
compositions (density 0.916-0.919 g/cc).
[0014] FIG. 6 depicts some GPC MWD profiles and corresponding
comonomer distribution overlays for some inventive and comparative
compositions (density 0.924-0.926 g/cc).
[0015] FIG. 7 depicts some GPC MWD profiles and corresponding
comonomer distribution overlays for some inventive and comparative
compositions (Cast stretch).
DETAILED DESCRIPTION
[0016] It has been discovered that the inventive compositions can
be used to form inventive breathable films and related products.
Such compositions contain an ethylene-based polymer that has a
superior comonomer distribution, which is significantly higher in
comonomer concentration, and a good distribution of comonomer, in
the high molecular weight polymer molecules, and is significantly
lower in comonomer concentration in the low molecular weight
polymer molecules, as compared to conventional polymers of the art
at the same overall density. It has also been discovered that the
ethylene-based polymer has low LCB (Long Chain Branches), as
indicated by low ZSVR, as compared to conventional polymers. As a
result of this optimized distribution of the comonomer, as well as
the inherent low LCB nature, the inventive compositions have more
tie chains, and thus, improved film toughness. The inventive
compositions can be useful in forming the inventive breathable
films and related products of the present invention.
[0017] The invention provides a composition comprising a first
composition, comprising at least one ethylene-based polymer,
wherein the first composition comprises a MWCDI value greater than
0.9, and a melt index ratio (I10/I2) that meets the following
equation: I10/I2.gtoreq.7.0-1.2.times.log(I2).
[0018] The inventive composition may comprise a combination of two
or more embodiments described herein.
[0019] The first composition may comprise a combination of two or
more embodiments as described herein.
[0020] The ethylene-based polymer may comprise a combination of two
or more embodiments as described herein.
[0021] In one embodiment, the first composition has a MWCDI value
less than, or equal to, 10.0, further less than, or equal to, 8.0,
further less than, or equal to, 6.0.
[0022] In one embodiment, the first composition has a MWCDI value
less than, or equal to, 5.0, further less than, or equal to, 4.0,
further less than, or equal to, 3.0.
[0023] In one embodiment, the first composition has a MWCDI value
greater than, or equal to, 1.0, further greater than, or equal to,
1.1, further greater than, or equal to, 1.2.
[0024] In one embodiment, the first composition has a MWCDI value
greater than, or equal to, 1.3, further greater than, or equal to,
1.4, further greater than, or equal to, 1.5.
[0025] In one embodiment, the first composition has a melt index
ratio I10/I2 greater than, or equal to, 7.0, further greater than,
or equal to, 7.1, further greater than, or equal to, 7.2, further
greater than, or equal to, 7.3.
[0026] In one embodiment, the first composition has a melt index
ratio I10/I2 less than, or equal to, 9.2, further less than, or
equal to, 9.0, further less than, or equal to, 8.8, further less
than, or equal to, 8.5.
[0027] In one embodiment, the first composition has a ZSVR value
from 1.2 to 3.0, further from 1.2 to 2.5, further 1.2 to 2.0.
[0028] In one embodiment, the first composition has a vinyl
unsaturation level greater than 10 vinyls per 1,000,000 total
carbons. For example, greater than 20 vinyls per 1,000,000 total
carbons, or greater than 50 vinyls per 1,000,000 total carbons, or
greater than 70 vinyls per 1,000,000 total carbons, or greater than
100 vinyls per 1,000,000 total carbons.
[0029] In one embodiment, the first composition has a density in
the range of 0.910 to 0.940 g/cm.sup.3, for example from 0.910 to
0.935 g/cm.sup.3, or from 0.910 to 0.930 g/cm.sup.3, or from 0.910
to 0.925 g/cm.sup.3. For example, the density can be from a lower
limit of 0.910, 0.912, or 0.914 g/cm.sup.3, to an upper limit of
0.925, 0.927, 0.930, or 0.935 g/cm.sup.3 (1 cm.sup.3=1 cc).
[0030] In one embodiment, the first composition has a melt index
(I.sub.2 or I2; at 190.degree. C./2.16 kg) from 0.1 to 50 g/10
minutes, for example from 0.1 to 30 g/10 minutes, or from 0.1 to 20
g/10 minutes, or from 0.1 to 10 g/10 minutes. For example, the melt
index (I.sub.2 or I2; at 190.degree. C./2.16 kg) can be from a
lower limit of 0.1, 0.2, or 0.5 g/10 minutes, to an upper limit of
1.0, 2.0, 3.0, 4.0, 5.0, 10, 15, 20, 25, 30, 40, or 50 g/10
minutes.
[0031] In one embodiment, the first composition has a molecular
weight distribution, expressed as the ratio of the weight average
molecular weight to number average molecular weight
(M.sub.w/M.sub.n; as determined by conv. GPC) in the range of from
2.2 to 5.0. For example, the molecular weight distribution
(M.sub.w/M.sub.n) can be from a lower limit of 2.2, 2.3, 2.4, 2.5,
3.0, 3.2, or 3.4, to an upper limit of 3.9, 4.0, 4.1, 4.2, 4.5,
5.0.
[0032] In one embodiment, the first composition has a number
average molecular weight (M.sub.n; as determined by conv. GPC) in
the range from 10,000 to 50,000 g/mole. For example, the number
average molecular weight can be from a lower limit of 10,000,
20,000, or 25,000 g/mole, to an upper limit of 35,000, 40,000,
45,000, or 50,000 g/mole.
[0033] In one embodiment, the first composition has a weight
average molecular weight (M.sub.w; as determined by conv. GPC) in
the range from 70,000 to 200,000 g/mole. For example, the number
average molecular weight can be from a lower limit of 70,000,
75,000, or 78,000 g/mole, to an upper limit of 120,000, 140,000,
160,000, 180,000 or 200,000 g/mole.
[0034] In one embodiment, the first composition has a melt
viscosity ratio, Eta*0.1/Eta*100, in the range from 2.2 to 7.0. For
example, the number average molecular weight can be from a lower
limit of 2.2, 2.3, 2.4 or 2.5, to an upper limit of 6.0, 6.2, 6.5,
or 7.0.
[0035] In one embodiment, the ethylene-based polymer is an
ethylene/.alpha.-olefin interpolymer, and further an
ethylene/.alpha.-olefin copolymer.
[0036] In one embodiment, the first ethylene-based polymer is an
ethylene/.alpha.-olefin interpolymer, and further an
ethylene/.alpha.-olefin copolymer.
[0037] In one embodiment, the a-olefin has less than, or equal to,
20 carbon atoms. For example, the .alpha.-olefin comonomers may
preferably have 3 to 10 carbon atoms, and more preferably 3 to 8
carbon atoms. Exemplary .alpha.-olefin comonomers include, but are
not limited to, propylene, 1-butene, 1-pentene, 1-hexene,
1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene.
The one or more .alpha.-olefin comonomers may, for example, be
selected from the group consisting of propylene, 1-butene,
1-hexene, and 1-octene; or in the alternative, from the group
consisting of 1-butene, 1-hexene and 1-octene, and further 1-hexene
and 1-octene.
[0038] In one embodiment, the ethylene-based polymer, or first
ethylene-based polymer, has a molecular weight distribution
(M.sub.w/M.sub.n; as determined by conv. GPC) in the range from 1.5
to 4.0, for example, from 1.5 to 3.5, or from 2.0 to 3.0. For
example, the molecular weight distribution (M.sub.w/M.sub.n) can be
from a lower limit of 1.5, 1.7, 2.0, 2.1, or 2.2, to an upper limit
of 2.5, 2.6, 2.8, 3.0, 3.5, or 4.0.
[0039] In one embodiment, the first composition further comprises a
second ethylene-based polymer. In a further embodiment, the second
ethylene-based polymer is an ethylene/.alpha.-olefin interpolymer,
and further an ethylene/.alpha.-olefin copolymer, or a LDPE.
[0040] In one embodiment, the .alpha.-olefin has less than, or
equal to, 20 carbon atoms. For example, the .alpha.-olefin
comonomers may preferably have 3 to 10 carbon atoms, and more
preferably 3 to 8 carbon atoms. Exemplary .alpha.-olefin comonomers
include, but are not limited to, propylene, 1-butene, 1-pentene,
1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and
4-methyl-1-pentene. The one or more .alpha.-olefin comonomers may,
for example, be selected from the group consisting of propylene,
1-butene, 1-hexene, and 1-octene; or in the alternative, from the
group consisting of 1-butene, 1-hexene and 1-octene, and further
1-hexene and 1-octene.
[0041] In one embodiment, the second ethylene-based polymer is a
heterogeneously branched ethylene/.alpha.-olefin interpolymer, and
further a heterogeneously branched ethylene/.alpha.-olefin
copolymer. Heterogeneously branched ethylene/a-olefin interpolymers
and copolymers are typically produced using Ziegler/Natta type
catalyst system, and have more comonomer distributed in the lower
molecular weight molecules of the polymer.
[0042] In one embodiment, the second ethylene-based polymer has a
molecular weight distribution (M.sub.w/M.sub.n) in the range from
3.0 to 5.0, for example from 3.2 to 4.6. For example, the molecular
weight distribution (M.sub.w/M.sub.n) can be from a lower limit of
3.2, 3.3, 3.5, 3.7, or 3.9, to an upper limit of 4.6, 4.7, 4.8,
4.9, or 5.0.
[0043] In one embodiment, the composition comprises from 50 to 80
wt %, or from 50 to 85 wt %, or from 50 to 90 wt %, or from 50 to
95 wt % of the first composition, based on the weight of the
composition.
[0044] In one embodiment, the composition comprises greater than,
or equal to, 80 wt %, or greater than, or equal to, 85 wt %, or
greater than, or equal to, 90 wt %, or greater than, or equal to,
95 wt %, or greater than, or equal to 98 wt % of the first
composition, based on the weight of the composition.
[0045] In one embodiment, the composition further comprises another
polymer. In a further embodiment, the polymer is selected from the
following: a LLDPE, a VLDPE (a very low density polyethylene), a
MDPE, a LDPE, a HDPE, a HMWHDPE (a high molecular weight HDPE), a
propylene-based polymer, a polyolefin plastomer, a polyolefin
elastomer, an olefin block copolymer, an ethylene vinyl acetate, an
ethylene acrylic acid, an ethylene methacrylic acid, an ethylene
methyl acrylate, an ethylene ethyl acrylate, an ethylene butyl
acrylate, a polyisobutylene, a maleic anhydride-grafted polyolefin,
an ionomer of any of the foregoing, or a combination thereof.
[0046] In one embodiment, the composition further comprises a LDPE.
In a further embodiment, the LDPE is present in an amount from 5 to
50 wt %, further from 10 to 40 wt %, further from 15 to 30 wt %,
based on the weight of the composition. In a further embodiment,
the LDPE has a density from 0.915 to 0.930 g/cc, and a melt index
(I2) from 0.15 to 30 g/10 min, further from 0.25 to 20 g/10
min.
[0047] In one embodiment, the composition further comprises one or
more additives.
[0048] The invention also provides an article comprising at least
one component formed from an inventive composition as described
herein. In a further embodiment, the article is a film.
[0049] In some embodiments, the present invention relates to a
breathable film formed from any of the inventive compositions as
described herein. In some embodiments, a first composition (formed
from an inventive composition described herein) in the breathable
film may have an MWCDI value less than, or equal to 10.0. In some
embodiments, the first composition used in the breathable film has
a density of 0.910 to 0.950 g/cm.sup.3 and/or a melt index (I2) of
0.5 to 30 g/10 minutes. The first composition used in the
breathable film, in some embodiments, has a density of 0.915 to
0.940 g/cm.sup.3. In some embodiments where the breathable film is
a cast film, the melt index can be from 0.8 to 15 g/10 minutes, or
from 1.5 to 5 g/10 minutes. In some embodiments where the
breathable film is a blown film, the melt index can be from 0.7 to
1.5 g/10 minutes.
[0050] In some embodiments, the breathable film further comprises
40 to 65 percent by weight of a mineral filler (e.g.,
CaCO.sub.3).
[0051] A breathable film, in some embodiments, has a basis weight
of 10 to 20 g/m.sup.2, or of 12 to 20 g/m.sup.2, or of 8 to 18
g/m.sup.2.
[0052] In some embodiments, the breathable film is a monolayer
film. The breathable film, in some embodiments, is a multilayer
film. In some embodiments, the breathabe film comprises up to 7
layers or, in the case of microlayer films, could comprise greater
than 15 or 25 layers.
[0053] In some embodiments, a first layer of the breathable film
can comprise, in addition to an inventive composition, a second
polymer, wherein the second polymer is selected from the following:
a LLDPE, a VLDPE, a LDPE, a MDPE, a HDPE, a HMWHDPE, a
propylene-based polymer, a polyolefin plastomer, a polyolefin
elastomer, an olefin block copolymer, an ethylene vinyl acetate, an
ethylene acrylic acid, an ethylene methacrylic acid, an ethylene
methyl acrylate, an ethylene ethyl acrylate, an ethylene butyl
acrylate, a polyisobutylene, a maleic anhydride-grafted polyolefin,
an ionomer of any of the foregoing, or a combination thereof.
[0054] In some embodiments where the breathable film is a
multilayer film, the film can further comprise a second layer,
wherein the second layer comprises a polymer selected from the
following: the inventive composition, a LLDPE, a VLDPE (a very low
density polyethylene), a MDPE, a LDPE, a HDPE, a HMWHDPE (a high
molecular weight HDPE), a propylene-based polymer, a polyolefin
plastomer, a polyolefin elastomer, an olefin block copolymer, an
ethylene vinyl acetate, an ethylene acrylic acid, an ethylene
methacrylic acid, an ethylene methyl acrylate, an ethylene ethyl
acrylate, an ethylene butyl acrylate, an isobutylene, a maleic
anhydride-grafted polyolefin, an ionomer of any of the foregoing,
or a combination thereof.
[0055] The breathable film, in some embodiments, comprises at least
30 weight percent of any of the inventive compositions disclosed
herein. In some embodiments, the breathable film comprises up to 60
weight percent of any of the inventive compositions disclosed
herein. The breathable film, in some embodiments, comprises from 40
to 60 weight percent of an inventive composition, or from 45 to 55
weight percent of an inventive composition.
[0056] In some embodiments, a breathable film exhibits a water
vapor transmission rate of at least 100 g/m.sup.2-day-atm and up to
10,000 g/m.sup.2-day-atm, preferably from 500 g/m.sup.2-day-atm to
10,000 g/m.sup.2-day-atm, or from 1,000 to 6,000 g/m.sup.2-day-atm,
or from 1,500 to 6,000 g/m.sup.2-day-atm.
[0057] The breathable film, in some embodiments, exhibits a
hydrohead of at least 60 cm as measured by EN 20811.
[0058] In some embodiments, the breathable film is oriented in at
least the machine direction.
[0059] Some embodiments of the present invention relate to
laminates comprising a breathable film as disclosed herein. In some
such embodiments, the laminate may further comprise a non-woven
material. Some embodiments of the present invention relate to an
article comprising a laminate as disclosed herein.
[0060] Some embodiments of the present invention relate to an
article comprising a breathable film as disclosed herein.
Non-limiting examples of such articles can include backsheets for
baby diapers, training pants, adult incontinence products,
breathable barrier surgical gowns, housewrap, and filtration
products.
Polymerization
[0061] Polymerization processes include, but are not limited to,
solution polymerization processes, using one or more conventional
reactors, e.g., loop reactors, isothermal reactors, adiabatic
reactors, stirred tank reactors, autoclave reactors in parallel,
series, and/or any combinations thereof. The ethylene based polymer
compositions may, for example, be produced via solution phase
polymerization processes, using one or more loop reactors,
adiabatic reactors, and combinations thereof.
[0062] In general, the solution phase polymerization process occurs
in one or more well mixed reactors, such as one or more loop
reactors and/or one or more adiabatic reactors at a temperature in
the range from 115 to 250.degree. C.; for example, from 135 to
200.degree. C., and at pressures in the range of from 300 to 1000
psig, for example, from 450 to 750 psig.
[0063] In one embodiment, the ethylene based polymer composition
(e.g., the first composition of claim 1) may be produced in two
loop reactors in series configuration, the first reactor
temperature is in the range from 115 to 200.degree. C., for
example, from 135 to 165.degree. C., and the second reactor
temperature is in the range from 150 to 210.degree. C., for
example, from 185 to 200.degree. C. In another embodiment, the
ethylene based polymer composition may be produced in a single
reactor, and the reactor temperature is in the range from 115 to
200.degree. C., for example from 130 to 190.degree. C. The
residence time in a solution phase polymerization process is
typically in the range from 2 to 40 minutes, for example from 5 to
20 minutes. Ethylene, solvent, one or more catalyst systems,
optionally one or more cocatalysts, and optionally one or more
comonomers, are fed continuously to one or more reactors. Exemplary
solvents include, but are not limited to, isoparaffins. For
example, such solvents are commercially available under the name
ISOPAR E from ExxonMobil Chemical. The resultant mixture of the
ethylene based polymer composition and solvent is then removed from
the reactor or reactors, and the ethylene based polymer composition
is isolated. Solvent is typically recovered via a solvent recovery
unit, i.e., heat exchangers and separator vessel, and the solvent
is then recycled back into the polymerization system.
[0064] In one embodiment, the ethylene based polymer composition
may be produced, via a solution polymerization process, in a dual
reactor system, for example a dual loop reactor system, wherein
ethylene, and optionally one or more a-olefins, are polymerized in
the presence of one or more catalyst systems, in one reactor, to
produce a first ethylene-based polymer, and ethylene, and
optionally one or more .alpha.-olefins, are polymerized in the
presence of one or more catalyst systems, in a second reactor, to
produce a second ethylene-based polymer. Additionally, one or more
cocatalysts may be present.
[0065] In another embodiment, the ethylene based polymer
composition may be produced via a solution polymerization process,
in a single reactor system, for example, a single loop reactor
system, wherein ethylene, and optionally one or more
.alpha.-olefins, are polymerized in the presence of one or more
catalyst systems. Additionally, one or more cocatalysts may be
present.
[0066] As discussed above, the invention provides a process to form
a composition comprising at least two ethylene-based polymers, said
process comprising the following:
[0067] polymerizing ethylene, and optionally at least one
comonomer, in solution, in the presence of a catalyst system
comprising a metal-ligand complex of Structure I, to form a first
ethylene-based polymer; and
[0068] polymerizing ethylene, and optionally at least one
comonomer, in the presence of a catalyst system comprising a
Ziegler/Natta catalyst, to form a second ethylene-based polymer;
and wherein Structure I is as follows:
##STR00001##
wherein:
[0069] M is titanium, zirconium, or hafnium, each, independently,
being in a formal oxidation state of +2, +3, or +4; and
[0070] n is an integer from 0 to 3, and wherein when n is 0, X is
absent; and
[0071] each X, independently, is a monodentate ligand that is
neutral, monoanionic, or dianionic; or two Xs are taken together to
form a bidentate ligand that is neutral, monoanionic, or dianionic;
and
[0072] X and n are chosen, in such a way, that the metal-ligand
complex of formula (I) is, overall, neutral; and
[0073] each Z, independently, is O, S,
N(C.sub.1-C.sub.40)hydrocarbyl, or P(C.sub.1-C.sub.40)hydrocarbyl;
and
[0074] wherein the Z-L-Z fragment is comprised of formula (1):
##STR00002##
[0075] R.sup.1through R.sup.16 are each, independently, selected
from the group consisting of the following:
a substituted or unsubstituted (C.sub.1-C.sub.40)hydrocarbyl, a
substituted or unsubstituted (C.sub.1-C.sub.40)heterohydrocarbyl,
Si(R.sup.C).sub.3, Ge(R.sup.C).sub.3, P(R.sup.P).sub.2,
N(R.sup.N).sub.2, OR.sup.C, SR.sup.C, NO.sub.2, CN, CF.sub.3,
R.sup.CS(O)--, R.sup.CS(O).sub.2--, (R.sup.C).sub.2C.dbd.N--,
R.sup.CC(O)O--, R.sup.CC(O)O--, R.sup.CC(O)N(R)--,
(R.sup.C).sub.2NC(O)--, halogen atom, hydrogen atom; and wherein
each R.sup.C is independently a (C1-C30)hydrocarbyl; R.sup.P is a
(C1-C30)hydrocarbyl; and R.sup.N is a (C1-C30)hydrocarbyl; and
[0076] wherein, optionally, two or more R groups (from R.sup.1
through R.sup.16) can combine together into one or more ring
structures, with such ring structures each, independently, having
from 3 to 50 atoms in the ring, excluding any hydrogen atom.
[0077] An inventive process may comprise a combination of two or
more embodiments as described herein.
[0078] In one embodiment, said process comprises polymerizing
ethylene, and optionally at least one .alpha.-olefin, in solution,
in the presence of a catalyst system comprising a metal-ligand
complex of Structure I, to form a first ethylene-based polymer; and
polymerizing ethylene, and optionally at least one .alpha.-olefin,
in the presence of a catalyst system comprising a Ziegler/Natta
catalyst, to form a second ethylene-based polymer. In a further
embodiment, each .alpha.-olefin is independently a C1-C8
.alpha.-olefin.
[0079] In one embodiment, optionally, two or more R groups from
R.sup.9 through R.sup.13, or R.sup.4 through R.sup.8 can combine
together into one or more ring structures, with such ring
structures each, independently, having from 3 to 50 atoms in the
ring, excluding any hydrogen atom.
[0080] In one embodiment, M is hafnium.
[0081] In one embodiment, R.sup.3 and R.sup.14 are each
independently an alkyl, and further a C1-C3 alkyl, and further
methyl.
[0082] In one embodiment, R.sup.1 and R.sup.16 are each as
follows:
##STR00003##
[0083] In one embodiment, each of the aryl, heteroaryl,
hydrocarbyl, heterohydrocarbyl, Si(R.sup.C).sub.3,
Ge(R.sup.C).sub.3, P(R.sup.P).sub.2, N(R.sup.N).sub.2, OR.sup.C,
SR.sup.C, R.sup.CS(O)--, R.sup.CS(O).sub.2--,
(R.sup.C).sub.2C.dbd.N--, R.sup.CC(O)O--, R.sup.COC(O)--,
R.sup.CC(O)N(R)--, (R.sup.C).sub.2NC(O)--, hydrocarbylene, and
heterohydrocarbylene groups, independently, is unsubstituted or
substituted with one or more R.sup.S substituents; and each R.sup.S
independently is a halogen atom, polyfluoro substitution, perfluoro
substitution, unsubstituted (C.sub.1-C.sub.18)alkyl, F.sub.3C--,
FCH.sub.2O--, F.sub.2HCO--, F.sub.3CO--, R.sub.3Si--, R.sub.3Ge--,
RO--, RS--, RS(O)--, RS(O).sub.2--, R.sub.2P--, R.sub.2N--,
R.sub.2C.dbd.N--, NC--, RC(O)O--, ROC(O)--, RC(O)N(R)--, or
R.sub.2NC(O)--, or two of the R.sup.S are taken together to form an
unsubstituted (C.sub.1-C.sub.18)alkylene, wherein each R
independently is an unsubstituted (C.sub.1-C.sub.18)alkyl.
[0084] In one embodiment, two or more of R.sup.1 through R.sup.16
do not combine to form one or more ring structures.
[0085] In one embodiment, the catalyst system suitable for
producing the first ethylene/.alpha.-olefin interpolymer is a
catalyst system comprising
bis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethy-
l)-methylene-1,2-cyclohexanediylhafnium (IV) dimethyl, represented
by the following Structure IA:
##STR00004##
[0086] The Ziegler/Natta catalysts suitable for use in the
invention are typical supported, Ziegler-type catalysts, which are
particularly useful at the high polymerization temperatures of the
solution process. Examples of such compositions are those derived
from organomagnesium compounds, alkyl halides or aluminum halides
or hydrogen chloride, and a transition metal compound. Examples of
such catalysts are described in U.S. Pat. Nos. 4,612,300;
4,314,912; and 4,547,475; the teachings of which are incorporated
herein by reference.
[0087] Particularly suitable organomagnesium compounds include, for
example, hydrocarbon soluble dihydrocarbylmagnesium, such as the
magnesium dialkyls and the magnesium diaryls. Exemplary suitable
magnesium dialkyls include, particularly,
n-butyl-sec-butylmagnesium, diisopropylmagnesium,
di-n-hexylmagnesium, isopropyl-n-butyl-magnesium,
ethyl-n-hexyl-magnesium, ethyl-n-butylmagnesium,
di-n-octylmagnesium, and others, wherein the alkyl has from 1 to 20
carbon atoms. Exemplary suitable magnesium diaryls include
diphenylmagnesium, dibenzylmagnesium and ditolylmagnesium. Suitable
organomagnesium compounds include alkyl and aryl magnesium
alkoxides and aryloxides and aryl and alkyl magnesium halides, with
the halogen-free organomagnesium compounds being more
desirable.
[0088] Halide sources include active non-metallic halides, metallic
halides, and hydrogen chloride. Suitable non-metallic halides are
represented by the formula R'X, wherein R' is hydrogen or an active
monovalent organic radical, and X is a halogen. Particularly
suitable non-metallic halides include, for example, hydrogen
halides and active organic halides, such as t-alkyl halides, allyl
halides, benzyl halides and other active hydrocarbyl halides. By an
active organic halide is meant a hydrocarbyl halide that contains a
labile halogen at least as active, i.e., as easily lost to another
compound, as the halogen of sec-butyl chloride, preferably as
active as t-butyl chloride. In addition to the organic monohalides,
it is understood that organic dihalides, trihalides and other
polyhalides that are active, as defined hereinbefore, are also
suitably employed. Examples of preferred active non-metallic
halides, include hydrogen chloride, hydrogen bromide, t-butyl
chloride, t-amyl bromide, allyl chloride, benzyl chloride, crotyl
chloride, methylvinyl carbinyl chloride, a-phenylethyl bromide,
diphenyl methyl chloride, and the like. Most preferred are hydrogen
chloride, t-butyl chloride, allyl chloride and benzyl chloride.
[0089] Suitable metallic halides include those represented by the
formula MRy-a Xa, wherein: M is a metal of Groups IIB, IIIA or IVA
of Mendeleev's periodic Table of Elements; R is a monovalent
organic radical; X is a halogen; y has a value corresponding to the
valence of M; and "a" has a value from 1 to y. Preferred metallic
halides are aluminum halides of the formula AlR.sub.3-aX.sub.a,
wherein each R is independently hydrocarbyl, such as alkyl; X is a
halogen; and "a" is a number from 1 to 3. Most preferred are
alkylaluminum halides, such as ethylaluminum sesquichloride,
diethylaluminum chloride, ethylaluminum dichloride, and
diethylaluminum bromide, with ethylaluminum dichloride being
especially preferred. Alternatively, a metal halide, such as
aluminum trichloride, or a combination of aluminum trichloride with
an alkyl aluminum halide, or a trialkyl aluminum compound may be
suitably employed.
[0090] Any of the conventional Ziegler-Natta transition metal
compounds can be usefully employed, as the transition metal
component in preparing the supported catalyst component. Typically,
the transition metal component is a compound of a Group IVB, VB, or
VIB metal. The transition metal component is generally, represented
by the formulas: TrX'.sub.4-q (OR1)q, TrX'.sub.4-q (R2)q,
VOX'.sub.3 and VO(OR).sub.3.
[0091] Tr is a Group IVB, VB, or VIB metal, preferably a Group IVB
or VB metal, preferably titanium, vanadium or zirconium; q is 0 or
a number equal to, or less than, 4; X' is a halogen, and R1 is an
alkyl group, aryl group or cycloalkyl group having from 1 to 20
carbon atoms; and R2 is an alkyl group, aryl group, aralkyl group,
substituted aralkyls, and the like.
[0092] The aryl, aralkyls and substituted aralkys contain 1 to 20
carbon atoms, preferably 1 to 10 carbon atoms. When the transition
metal compound contains a hydrocarbyl group, R2, being an alkyl,
cycloalkyl, aryl, or aralkyl group, the hydrocarbyl group will
preferably not contain an H atom in the position beta to the metal
carbon bond. Illustrative, but non-limiting, examples of aralkyl
groups are methyl, neopentyl, 2,2-dimethylbutyl, 2,2-dimethylhexyl;
aryl groups such as benzyl; cycloalkyl groups such as 1-norbornyl.
Mixtures of these transition metal compounds can be employed if
desired.
[0093] Illustrative examples of the transition metal compounds
include TiCl.sub.4, TiBr.sub.4, Ti(OC.sub.2H.sub.5).sub.3Cl,
Ti(OC.sub.2H.sub.5)Cl.sub.3, Ti(OC.sub.4H.sub.9).sub.3Cl ,
Ti(OC.sub.3H.sub.7).sub.2Cl .sub.0.2,
Ti(OC.sub.6H.sup.13).sub.2Cl.sub.2,
Ti(OC.sub.8H.sub.17).sub.2Br.sub.2, and
Ti(OC.sub.12H.sub.25)Cl.sub.3, Ti(O-iC.sub.3H.sub.7).sub.4, and
Ti(O-nC.sub.4H.sub.9).sub.4. Illustrative examples of vanadium
compounds include VCl.sub.4, VOCl.sub.3, VO(OC.sub.2H.sub.5).sub.3,
and VO(OC.sub.4H.sub.9).sub.3. Illustrative examples of zirconium
compounds include ZrCl.sub.4, ZrCl.sub.3(OC.sub.2H.sub.5),
ZrCl.sub.2(OC.sub.2H.sub.5).sub.2, ZrCl(OC.sub.2H.sub.5).sub.3,
Zr(OC.sub.2H.sub.5).sub.4, ZrCl.sub.3(OC.sub.4H.sub.9),
ZrCl.sub.2(OC.sub.4H.sub.9).sub.2, and ZrCl
(OC.sub.4H.sub.9).sub.3.
[0094] An inorganic oxide support may be used in the preparation of
the catalyst, and the support may be any particulate oxide, or
mixed oxide which has been thermally or chemically dehydrated, such
that it is substantially free of adsorbed moisture. See U.S. Pat.
Nos. 4,612,300; 4,314,912; and 4,547,475; the teachings of which
are incorporated herein by reference.
[0095] In one embodiment, the composition comprises a MWCDI value
greater than 0.9.
[0096] In one embodiment, the composition comprises a melt index
ratio (I10/I2) that meets the following equation:
I10/I2.gtoreq.7.0-1.2.times.log(I2).
[0097] The composition may comprise one embodiment, or a
combination of two or more embodiments, as listed above for the
"first composition."
[0098] An inventive process may comprise a combination of two or
more embodiments described herein.
Co-Catalyst Component
[0099] The above described catalyst systems can be rendered
catalytically active by contacting it to, or combining it with, the
activating co-catalyst, or by using an activating technique, such
as those known in the art, for use with metal-based olefin
polymerization reactions. Suitable activating co-catalysts, for use
herein, include alkyl aluminums; polymeric or oligomeric alumoxanes
(also known as aluminoxanes); neutral Lewis acids; and
non-polymeric, non-coordinating, ion-forming compounds (including
the use of such compounds under oxidizing conditions). A suitable
activating technique is bulk electrolysis. Combinations of one or
more of the foregoing activating co-catalysts and techniques are
also contemplated. The term "alkyl aluminum" means a monoalkyl
aluminum dihydride or monoalkylaluminum dihalide, a dialkyl
aluminum hydride or dialkyl aluminum halide, or a trialkylaluminum.
Aluminoxanes and their preparations are known at, for example, U.S.
Pat. No. 6,103,657. Examples of preferred polymeric or oligomeric
alumoxanes are methylalumoxane, triisobutylaluminum-modified
methylalumoxane, and isobutylalumoxane.
[0100] Exemplary Lewis acid activating co-catalysts are Group 13
metal compounds containing from 1 to 3 hydrocarbyl substituents as
described herein. In some embodiments, exemplary Group 13 metal
compounds are tri(hydrocarbyl)-substituted-aluminum or
tri(hydrocarbyl)-boron compounds. In some other embodiments,
exemplary Group 13 metal compounds are
tri(hydrocarbyl)-substituted-aluminum or tri(hydrocarbyl)-boron
compounds are tri((C.sub.1-C.sub.10)alkyl)aluminum or
tri((C.sub.6-C.sub.18)aryl)boron compounds and halogenated
(including perhalogenated) derivatives thereof. In some other
embodiments, exemplary Group 13 metal compounds are
tris(fluoro-substituted phenyl)boranes, in other embodiments,
tris(pentafluorophenyl)borane. In some embodiments, the activating
co-catalyst is a tris((C.sub.1-C.sub.20)hydrocarbyl) borate (e.g.,
trityl tetrafluoroborate) or a
tri((C.sub.1-C.sub.20)hydrocarbyl)ammonium
tetra((C.sub.1-C.sub.20)hydrocarbyl)borane (e.g.,
bis(octadecyl)methylammonium tetrakis(pentafluorophenyl)borane). As
used herein, the term "ammonium" means a nitrogen cation that is a
((C.sub.1-C.sub.20)hydrocarbyl).sub.4N.sup.+, a
((C.sub.1-C.sub.20)hydrocarbyl).sub.3N(H)+, a
((C.sub.1-C.sub.20)hydrocarbyl).sub.2N(H).sub.2.sup.+,
(C.sub.1-C.sub.20)hydrocarbylN(H).sub.3.sup.+, or N(H).sub.4.sup.+,
wherein each (C.sub.1-C.sub.20)hydrocarbyl may be the same or
different.
[0101] Exemplary combinations of neutral Lewis acid activating
co-catalysts include mixtures comprising a combination of a
tri((C.sub.1-C.sub.4)alkyl)aluminum and a halogenated
tri((C.sub.6-C.sub.18)aryl)boron compound, especially a
tris(pentafluorophenyl)borane. Other exemplary embodiments are
combinations of such neutral Lewis acid mixtures with a polymeric
or oligomeric alumoxane, and combinations of a single neutral Lewis
acid, especially tris(pentafluorophenyl)borane with a polymeric or
oligomeric alumoxane. Exemplary embodiments ratios of numbers of
moles of (metal-ligand complex):(tris(pentafluoro-phenylborane):
(alumoxane) [e.g., (Group 4 metal-ligand
complex):(tris(pentafluoro-phenylborane):(alumoxane)] are from
1:1:1 to 1:10:30, other exemplary embodiments are from 1:1:1.5 to
1:5:10.
[0102] Many activating co-catalysts and activating techniques have
been previously taught, with respect to different metal-ligand
complexes, in the following U.S. patents: U.S. Pat. No. 5,064,802;
U.S. Pat. No. 5,153,157; U.S. Pat, No. 5,296,433; U.S. Pat. No.
5,321,106; U.S. Pat. No. 5,350,723; U.S. Pat. No. 5,425,872; U.S.
Pat. No. 5,625,087; U.S. Pat. No. 5,721,185; U.S. Pat. No.
5,783,512; U.S. Pat. No. 5,883,204; U.S. Pat. No. 5,919,983; U.S.
Pat. No. 6,696,379; and U.S. Pat. No. 7,163,907. Examples of
suitable hydrocarbyloxides are disclosed in U.S. Pat. No.
5,296,433. Examples of suitable Bronsted acid salts for addition
polymerization catalysts are disclosed in U.S. Pat. No. 5,064,802;
U.S. Pat. No. 5,919,983; U.S. 5,783,512. Examples of suitable salts
of a cationic oxidizing agent and a non-coordinating, compatible
anion, as activating co-catalysts for addition polymerization
catalysts, are disclosed in U.S. Pat. No.5,321,106. Examples of
suitable carbenium salts as activating co-catalysts for addition
polymerization catalysts are disclosed in U.S. Pat. No. 5,350,723.
Examples of suitable silylium salts, as activating co-catalysts for
addition polymerization catalysts, are disclosed in U.S. Pat. No.
5,625,087. Examples of suitable complexes of alcohols, mercaptans,
silanols, and oximes with tris(pentafluorophenyl)borane are
disclosed in U.S. Pat. No. 5,296,433. Some of these catalysts are
also described in a portion of U.S. Pat. No. 6,515,155 B1,
beginning at column 50, at line 39, and going through column 56, at
line 55, only the portion of which is incorporated by reference
herein.
[0103] In some embodiments, the above described catalyst systems
can be activated to form an active catalyst composition by
combination with one or more cocatalyst, such as 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. Exemplary suitable
cocatalysts include, but are not limited to, modified methyl
aluminoxane (MMAO), bis(hydrogenated tallow alkyl)methyl,
tetrakis(pentafluorophenyl)borate(1-) amine, triethyl aluminum
(TEA), and any combinations thereof.
[0104] In some embodiments, one or more of the foregoing activating
co-catalysts are used in combination with each other. In one
embodiment, a combination of a mixture of a
tri((C.sub.1-C.sub.4)hydrocarbyl)aluminum,
tri((C.sub.1-C.sub.4)hydrocarbyl)borane, or an ammonium borate with
an oligomeric or polymeric alumoxane compound, can be used.
Additives, Additional Polymers and Applications
[0105] An inventive composition may comprise one or more additives.
Additives include, but are not limited to, antistatic agents, color
enhancers, dyes, lubricants, fillers (for example,TiO.sub.2 or
CaCO.sub.3), opacifiers, nucleators, processing aids, pigments,
primary anti-oxidants, secondary anti-oxidants, UV stabilizers,
anti-blocks, slip agents, tackifiers, fire retardants,
anti-microbial agents, odor reducer agents, anti-fungal agents, and
combinations thereof. In some embodiments, an inventive composition
may comprise from about 0.001 to about 10 percent by the combined
weight of such additives, based on the weight of the composition
including such additives.
[0106] In breathable film applications (e.g., diaper, training
pants, and adult incontinence backsheet films, surgical gowns,
protective clothing, housewrap, etc.), large amounts of
CaCO.sub.3,or other mineral fillers, may be incorporated as a
filler to increase WVTR and other properties related to
breathability. For example, in some embodiments, a breathable film
can comprise at least 20% by weight CaCO.sub.3, or at least 30% by
weight CaCO.sub.3, or at least 40% by weight CaCO.sub.3 based on
the total weight of the film. In some embodiments, a breathable
film can comprise up to 70% by weight CaCO.sub.3, or up to 65% by
weight CaCO.sub.3, or up to 60% by weight CaCO.sub.3 based on the
total weight of the film. A breathable film, in some embodiments
can comprise from 20% to 70% by weight CaCO.sub.3, or from 30% to
70% by weight CaCO.sub.3, or from 40% to 65% by weight CaCO.sub.3,
or from 40% to 60% by weight CaCO.sub.3 based on the total weight
of the film.
[0107] An inventive composition may further comprise one or more
other polymers. For example one or more other ethylene-based
polymers (such polymers differ in one or more properties from the
ethylene-based polymer of the first composition and the second
ethylene-based polymer; i.e., density, melt index, comonomer, Mn,
Mw, and/or MWD), or one or more propylene-based polymers, or
combinations thereof.
[0108] Inventive compositions can be blended with other polymers to
provide a resin in some embodiments. Non-limiting examples of other
polymers that can blended with one or more inventive compositions
include a LLDPE, a VLDPE, a LDPE, a MDPE, a HDPE, a HMWHDPE, a
propylene-based polymer, a polyolefin plastomer, a polyolefin
elastomer, an olefin block copolymer, an ethylene vinyl acetate, an
ethylene acrylic acid, an ethylene methacrylic acid, an ethylene
methyl acrylate, an ethylene ethyl acrylate, an ethylene butyl
acrylate, a polyisobutylene, a maleic anhydride-grafted polyolefin,
an ionomer of any of the foregoing, or a combination thereof. Such
compositions may be blended via any method, known to a person of
ordinary skill in the art, including, but not limited to, dry
blending, and melt blending via any suitable equipment, for
example, an extruder. The resin further comprises a mineral filler,
such as CaCO.sub.3, to enable the microporous morphology and
breathability that results from stretching the film comprising the
resin. As noted in "The Role of Calcium Carbonate in Microporous
Film Applications" by Deeba Ansara, Allison Calhoun, and Paul
Merriman, PMA124PL, November 2001: "[Typically] stearic acid coated
CaCO3 is used to enable free-flowing CaCO.sub.3, that is easier to
handle, compound, and disperse in the polymer. This coating results
in a hydrophobic particle. The orientation process creates
microvoids where the polymer separates from the calcium carbonate
particles." Thus, in some embodiments using CaCO.sub.3 as a mineral
filler, the CaCO.sub.3 can be coated with stearic acid. In some
embodiments, the resin may comprise 45-80% CaCO.sub.3 by weight
based on the weight of the compound. In some such embodiments, the
resin can provide a good dispersion of the CaCO.sub.3 and can then
be let down with other resins to provide a breathable film having a
desired CaCO.sub.3 concentration (e.g., 45-60% by weight
CaCO.sub.3).
[0109] In some embodiments, the present invention relates to a
breathable film formed from any of the inventive compositions as
described herein. In some embodiments, the breathable film is a
monolayer film. The breathable film, in some embodiments, is a
multilayer film. Breathable films can be formed from inventive
compositions using methods and equipment well-known to those of
skill in the art. For example, breathable films can be produced via
a blown or cast film extrusion process and then stretched/oriented
in a semi-solid state below the melting point of the polymer or
polymer blend.
[0110] The amount of the inventive composition to use in breathable
films of the present invention can depend on a number of factors
including, for example, whether the film is a monolayer or
multilayer film, the other layers in the film if it is a multilayer
film, the desired properties of the film, the end use application
of the film, the desired properties of the film, the equipment
available to manufacture the film, and others. A breathable film of
the present invention, in some embodiments, comprises at least 20
percent by weight of the inventive composition, or at least 30
percent by weight of the inventive composition, or at least 40
percent by weight of the inventive composition.
[0111] In embodiments where the breathable film comprises a
multilayer film, the number of layers in the film can depend on a
number of factors including, for example, the desired properties of
the film, the desired thickness of the film, the content of the
other layers of the film, whether any of the layers in the film are
to be foamed, the end use application of the film, the equipment
available to manufacture the film, and others. A multilayer
breathable film can comprise up to 2, 3, 4, 5, 6, 7, 8, 9, 10, or
11 layers in various embodiments.
[0112] The inventive composition, in some embodiments, can be used
in more than one layer of the film. Other layers within a
multilayer film of the present invention can comprise, in various
embodiments, a polymer selected from the following: the inventive
composition, a LLDPE, a VLDPE (a very low density polyethylene), a
MDPE, a LDPE, a HDPE, a HMWHDPE (a high molecular weight HDPE), a
propylene-based polymer, a polyolefin plastomer, a polyolefin
elastomer, an olefin block copolymer, an ethylene vinyl acetate, an
ethylene acrylic acid, an ethylene methacrylic acid, an ethylene
methyl acrylate, an ethylene ethyl acrylate, an ethylene butyl
acrylate, an isobutylene, a maleic anhydride-grafted polyolefin, an
ionomer of any of the foregoing, or a combination thereof. In some
embodiments, a multilayer film of the present invention can
comprise one or more tie layers known to those of skill in the
art.
[0113] Breathable films can be coextrusions comprising two or more
layers in some embodiments. Common film structures include, for
example, a/b/a structures, a/b/c structures and others. Individual
layers within a film structure can be 1% to 99% of the multilayer
film based on the total weight of the film. Exemplary
configurations include 10%/80%/10%, 20%/60%/20%, 1%/98%/1%, and
others. Breathable films that are coextruded can be advantageous in
some applications as they can, in some embodiments, achieve better
bonding (e.g. thermal, adhesive, or ultrasonic) between the
breathable film and another substrate, impart stiffness, and/or
provide different haptics. In such multi-layer films, one or more
of the additional layers (in addition to the layer comprising an
inventive composition) can comprise a polymer selected from the
following: an inventive composition, a LLDPE, a VLDPE, a LDPE, a
MDPE, a HDPE, a HMWHDPE, a propylene-based polymer, a polyolefin
plastomer, a polyolefin elastomer, an olefin block copolymer, an
ethylene vinyl acetate, an ethylene acrylic acid, an ethylene
methacrylic acid, an ethylene methyl acrylate, an ethylene ethyl
acrylate, an ethylene butyl acrylate, a polyisobutylene, a maleic
anhydride-grafted polyolefin, an ionomer of any of the foregoing,
or combinations thereof.
[0114] As noted above, after formation of the film (e.g., via blown
or cast film extrusion processes), the film is then stretched or
oriented. Often, the film is heated prior to the stretching step to
a temperature above its glass transition temperature, but below its
melt temperature, such that it is stretched in a semi-solid state.
Stretch methods include orientation in the machine direction or the
use of ring rolling or intermeshing gears. In machine direction
orientation (MDO), the film can then be heated via contact with
heated rollers prior to being stretched between sets of rollers as
is known to those of skill in the art. See, e.g., P. C. Wu et al.,
"Novel Microporous Films and Their Composites," Journal of
Engineered Fibers and Fabrics, Vol. 2, Issue 1, 49-59 (2007). The
film is typically stretched between driven rollers whereby pairs of
consecutive rollers are driven at progressively higher speeds to
induce stretching (see, e.g., Wu et al., p. 53 at FIG. 7). Films
are typically stretched from 1.5 to 5.times. their original length
depending upon the properties desired. Higher levels of stretch
impart larger pore sizes and higher levels of breathability in the
film. Higher stretch can also impart splittiness or low tear
properties in the film. Processability or stretch window is
measured in terms of the minimum amount of stretch needed to create
a uniformly stretched film without the haze variations, often
referred to as tiger striping, to the maximum amount of stretch
that a film can withstand without creating pinholes or breaks in
the web. Films with a larger stretch window can enable a wider
range of performance properties and can be more resistant to
pinholing and web breaks.
[0115] In orientation by ring rolling or with intermeshing gears
(IMG), the film may also be heated to a temperature below its
melting point via contact with heated rolls. The film is stretched
between intermeshing rings or gears. The degree of stretching is
controlled by the depth of engagement of an individual ring gear or
ring relative to the adjacent ring(s) or gear(s). Such techniques
are generally known to those of skill in the art. For example, U.S.
Pat. Nos. 4,116,892 and 4,153,751, which are incorporated herein by
reference, provide additional information about ring rolling
processes.
[0116] In both MDO and IMG processes, the films can be annealed
after the stretching process. In some embodiments, the films can be
stretched in 1 direction, such as with MDO or a single IMG step, of
either machine direction stretching or cross direction stretching.
Films can be stretched in two directions in series such as MDO
followed by an IMG step to stretch in the cross direction. Another
alternative is stretching in the machine direction via IMG followed
by cross direction stretching via IMG. Yet another means of
multi-direction stretching is via a tentering process.
[0117] Breathable films can have basis weights ranging from 8 to 24
grams per square meter or in the alternative, from 10 to 20
g/m.sup.2 or in the alternative, from 12-18 g/m.sup.2. The basis
weight of the breathable film can depend on a number of factors
including the desired properties of the film, the end use
application of the film, the equipment available to manufacture the
film, the cost allowed by the application, and other factors.
[0118] In some embodiments, a breathable film of the present
invention can exhibit a water vapor transmission rate of at least
100 g/m.sup.2-day-atm when measured in accordance with ASTM D-6701.
A breathable film of the present invention, in some embodiments,
can exhibit a water vapor transmission rate of at least 100
g/m.sup.2-day-atm and up to 10,000 g/m.sup.2-day-atm when measured
in accordance with ASTM D-6701. In some embodiments, a breathable
film of the present invention can exhibit a water vapor
transmission rate of at least 500 g/m.sup.2-day-atm and up to
10,000 g/m.sup.2-day-atm when measured in accordance with ASTM
D-6701. A breathable film of the present invention, in some
embodiments, can exhibit a water vapor transmission rate of at
least 1,000 g/m.sup.2-day-atm and up to 6,000 g/m.sup.2-day-atm
when measured in accordance with ASTM D-6701. A breathable film of
the present invention, in some embodiments, can exhibit a water
vapor transmission rate of at least 1,500 g/m.sup.2-day-atm and up
to 6,000 g/m.sup.2-day-atm when measured in accordance with ASTM
D-6701.
[0119] In some embodiments, a breathable film of the present
invention can exhibit a hydrohead of at least 60 cm as measured by
EN 20811.
[0120] It is also contemplated that a breathable film may comprise
additional layers, either coextruded, or as a laminate. These
layers may be selected to provide additional functionality, for
example, layers to provide extra strength, adhesion to another
substrate such as a non-woven, and/or aesthetic properties such as
feel or appearance.
[0121] Some embodiments of the present invention relate to
laminates comprising one or more breathable films of the present
invention. For example, breathable films of the present invention
can be used in film/non-woven laminates. Typical non-wovens for use
in such laminates can be spunlaid, airlaid, carded webs, or
composities thereof. Typical non-woven composites for use in
laminates with a breathable film of the present invention include
three beams of spunbond, (e.g., S/S/S), a
spunbond/meltblown/spunbond composite (e.g., S/M/S), and others.
Common methods for joining the film to the non-wovens include, for
example, bonded hot melt adhesive lamination, ultra-sonic bonding,
and thermal bonding through a calendar or nip roll.
[0122] The present invention also relates to articles comprising at
least one component formed from an inventive composition. The
component can be, for example, a breathable film or film laminate.
Such components can be used in disposable hygiene and medical
products as liquid impermeable but breathable layers. Examples of
articles comprising such breathable films or film laminates include
diapers, training pants, feminine hygiene products, adult
incontinence products, medical drapes, medical gowns, surgical
suits, and others. In articles such as diaper, training pants,
feminine hygiene products, and adult incontinence products, a
breathable film or film laminate is also often referred to as a
backsheet. In medical products, a breathable film or film laminate
are often referred to as the "barrier layer" as the breathable film
or film laminate can prevent contamination from a health care
worker to a patient and vice versa. Breathable films can be
incorporated into such articles using techniques known to those of
skill in the art based on the teachings herein.
DEFINITIONS
[0123] Unless stated to the contrary, implicit from the context, or
customary in the art, all parts and percents are based on weight,
and all test methods are current as of the filing date of this
disclosure.
[0124] The term "composition," as used herein, includes material(s)
which comprise the composition, as well as reaction products and
decomposition products formed from the materials of the
composition.
[0125] The term "comprising," and derivatives thereof, is not
intended to exclude the presence of any additional component, step
or procedure, whether or not the same is disclosed herein. In order
to avoid any doubt, all compositions claimed herein through use of
the term "comprising" may include any additional additive,
adjuvant, or compound, whether polymeric or otherwise, unless
stated to the contrary. In contrast, 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.
[0126] 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 trace amounts of
impurities can be incorporated into the polymer structure), and the
term interpolymer as defined hereinafter. Trace amounts of
impurities may be incorporated into and/or within the polymer.
[0127] The term "interpolymer," as used herein, refers to a polymer
prepared by the polymerization of at least two different types of
monomers. The generic term interpolymer thus 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.
[0128] The term, "olefin-based polymer," as used herein, refers to
a polymer that comprises, in polymerized form, a majority amount of
olefin monomer, for example ethylene or propylene (based on the
weight of the polymer), and optionally may comprise at least one
polymerized comonomer.
[0129] The term, "ethylene-based polymer," as used herein, refers
to a polymer that comprises a majority amount of polymerized
ethylene monomer (based on the total weight of the polymer), and
optionally may comprise at least one polymerized comonomer.
[0130] The term, "ethylene/.alpha.-olefin interpolymer," as used
herein, refers to an interpolymer that comprises, in polymerized
form, a majority amount of ethylene monomer (based on the weight of
the interpolymer), and at least one .alpha.-olefin.
[0131] The term, "ethylene/.alpha.-olefin copolymer," as used
herein, refers to a copolymer that comprises, in polymerized form,
a majority amount of ethylene monomer (based on the weight of the
copolymer), and an .alpha.-olefin, as the only two monomer
types.
[0132] The term "propylene-based polymer," as used herein, refers
to a polymer that comprises, in polymerized form, a majority amount
of propylene monomer (based on the total weight of the polymer) and
optionally may comprise at least one polymerized comonomer.
TEST METHODS
Melt Index
[0133] Melt indices I.sub.2 (or I2) and I.sub.10 (or I10) were
measured in accordance to ASTM D-1238 (method B) at 190.degree. C.
and at 2.16 kg and 10 kg load, respectively. Their values are
reported in g/10 min.
Density
[0134] Samples for density measurement were prepared according to
ASTM D4703. Measurements were made, according to ASTM D792, Method
B, within one hour of sample pressing.
Dynamic Shear Rheology
[0135] Each sample was compression-molded into "3 mm thick.times.25
mm diameter" circular plaque, at 177.degree. C., for five minutes,
under 10 MPa pressure, in air. The sample was then taken out of the
press and placed on a counter top to cool.
[0136] Constant temperature, frequency sweep measurements were
performed on an ARES strain controlled rheometer (TA Instruments),
equipped with 25 mm parallel plates, under a nitrogen purge. For
each measurement, the rheometer was thermally equilibrated, for at
least 30 minutes, prior to zeroing the gap. The sample disk was
placed on the plate, and allowed to melt for five minutes at
190.degree. C. The plates were then closed to 2 mm, the sample
trimmed, 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 from 0.1 to 100 rad/s, at five points per decade
interval. The strain amplitude was constant at 10%. The stress
response was analyzed in terms of amplitude and phase, from which
the storage modulus (G'), loss modulus (G''), complex modulus (G*),
dynamic viscosity (.eta.*or Eta*), and tan .delta.(or tan delta)
were calculated.
Conventional Gel Permeation Chromatography (conv. GPC)
[0137] A GPC-IR high temperature chromatographic system from
PolymerChar (Valencia, Spain), was equipped with a Precision
Detectors (Amherst, MA), 2-angle laser light scattering detector
Model 2040, an IR5 infra-red detector and a 4-capillary viscometer,
both from PolymerChar. Data collection was performed using
PolymerChar Instrument Control software and data collection
interface. The system was equipped with an on-line, solvent degas
device and pumping system from Agilent Technologies (Santa Clara,
Calif.).
[0138] Injection temperature was controlled at 150 degrees Celsius.
The columns used, were three, 10-micron "Mixed-B" columns from
Polymer Laboratories (Shropshire, UK). The solvent used was
1,2,4-trichlorobenzene. The samples were prepared at a
concentration of "0.1 grams of polymer in 50 milliliters of
solvent." The chromatographic solvent and the sample preparation
solvent each contained "200 ppm of butylated hydroxytoluene (BHT)."
Both solvent sources were nitrogen sparged. Ethylene-based polymer
samples were stirred gently at 160 degrees Celsius for three hours.
The injection volume was "200 microliters,` and the flow rate was
"1 milliliters/minute." The GPC column set was calibrated by
running 21 "narrow molecular weight distribution" polystyrene
standards. The molecular weight (MW) of the standards ranges from
580 to 8,400,000 g/mole, and the standards were contained in six
"cocktail" mixtures. Each standard mixture had at least a decade of
separation between individual molecular weights. The standard
mixtures were purchased from Polymer Laboratories. The polystyrene
standards were prepared at "0.025 g in 50 mL of solvent" for
molecular weights equal to, or greater than, 1,000,000 g/mole, and
at "0.050 g in 50 mL of solvent" for molecular weights less than
1,000,000 g/mole.
[0139] The polystyrene standards were dissolved at 80.degree. C.,
with gentle agitation, for 30 minutes. The narrow standards
mixtures were run first, and in order of decreasing "highest
molecular weight component," to minimize degradation. The
polystyrene standard peak molecular weights were converted to
polyethylene molecular weight using Equation 1 (as described in
Williams and Ward, J. Polym. Sci., Polym. Letters, 6, 621
(1968)):
Mpolyethylene=A.times.(Mpolystyrene).sup.B (Eqn. 1),
where M is the molecular weight, A is equal to 0.4316 and B is
equal to 1.0.
[0140] Number-average molecular weight (Mn(conv gpc)), weight
average molecular weight (Mw-conv gpc), and z-average molecular
weight (Mz(conv gpc)) were calculated according to Equations 2-4
below.
Mn ( conv gpc ) = i = RV integration start i = RV integration end (
IR measurement channel i ) i = RV integration start i = RV
integration end ( IR measurement channel i M PE i ) ( Eqn . 2 ) Mw
( conv gpc ) = i = RV integration start i = RV integration end ( M
PE i IR measurement channel i ) i = RV integration start i = RV
integration end ( IR measurement channel i ) ( Eqn . 3 ) Mz ( conv
gpc ) = i = RV integration start i = RV integration end ( M PE i 2
IR measurement channel i ) i = RV integration start i = RV
integration end ( M PE i IR measurement channel i ) ( Eqn . 4 )
##EQU00001##
[0141] In Equations 2-4, the RV is column retention volume
(linearly-spaced), collected at "1 point per second," the IR is the
baseline-subtracted IR detector signal, in Volts, from the IR5
measurement channel of the GPC instrument, and M.sub.PE is the
polyethylene-equivalent MW determined from Equation 1. Data
calculation were performed using "GPC One software (version
2.013H)" from PolymerChar.
Creep Zero Shear Viscosity Measurement Method
[0142] Zero-shear viscosities were obtained via creep tests, which
were 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 was set to test
temperature for at least 30 minutes, prior to zeroing the fixtures.
At the testing temperature, a compression molded sample disk was
inserted between the plates, and allowed to come to equilibrium for
five minutes. The upper plate was then lowered down to 50 .mu.m
(instrument setting) above the desired testing gap (1.5 mm). Any
superfluous material was trimmed off, and the upper plate was
lowered to the desired gap. Measurements were done under nitrogen
purging, at a flow rate of 5 L/min. The default creep time was set
for two hours. Each sample was compression-molded into a "2 mm
thick x 25 mm diameter" circular plaque, at 177.degree. C., for
five minutes, under 10 MPa pressure, in air. The sample was then
taken out of the press and placed on a counter top to cool.
[0143] A constant low shear stress of 20 Pa was applied for all of
the samples, to ensure that the steady state shear rate was low
enough to be in the Newtonian region. The resulting steady state
shear rates were in the range from 10.sup.-3 to 10.sup.-4 s.sup.-1
for the samples in this study. Steady state was 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) was creep
compliance and t was creep time. If the slope of the linear
regression was greater than 0.97, steady state was considered to be
reached, then the creep test was stopped. In all cases in this
study, the slope meets the criterion within one hour. The steady
state shear rate was 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. was strain. The
zero-shear viscosity was determined from the ratio of the applied
stress to the steady state shear rate.
[0144] In order to determine if the sample was degraded during the
creep test, a small amplitude oscillatory shear test was conducted
before, and after, the creep test, on the same specimen from 0.1 to
100 rad/s. The complex viscosity values of the two tests were
compared. If the difference of the viscosity values, at 0.1 rad/s,
was greater than 5%, the sample was considered to have degraded
during the creep test, and the result was discarded.
[0145] Zero-Shear Viscosity Ratio (ZSVR) is defined as the ratio of
the zero-shear viscosity (ZSV) of the branched polyethylene
material to the ZSV of a linear polyethylene material (see ANTEC
proceeding below) at the equivalent weight average molecular weight
(Mw(conv gpc)), according to the following Equation 5:
Z S V R = .eta. 0 B .eta. 0 L = .eta. 0 B 2.29 - 15 M w ( conv gpc
) 3.65 . ( Eqn . 5 ) ##EQU00002##
[0146] The ZSV value was obtained from creep test, at 190.degree.
C., via the method described above. The Mw(conv gpc) value was
determined by the conventional GPC method (Equation 3), as
discussed above. The correlation between ZSV of linear polyethylene
and its Mw(conv gpc) was established based on a series of linear
polyethylene reference materials. A description for the ZSV-Mw
relationship can be found in the ANTEC proceeding: Karjala et al.,
Detection of Low Levels of Long-chain Branching in Polyolefins,
Annual Technical Conference--Society of Plastics Engineers (2008),
66th 887-891.
.sup.1H NMR Method
[0147] A stock solution (3.26 g) was added to "0.133 g of the
polymer sample" in 10 mm NMR tube. The stock solution was a mixture
of tetrachloroethane-d.sub.2 (TCE) and perchloroethylene (50:50,
w:w) with 0.001M Cr.sup.3+. The solution in the tube was purged
with N.sub.2, for 5 minutes, to reduce the amount of oxygen. The
capped sample tube was left at room temperature, overnight, to
swell the polymer sample. The sample was dissolved at 110.degree.
C. with periodic vortex mixing. The samples were free of the
additives that may contribute to unsaturation, for example, slip
agents such as erucamide. Each .sup.1H NMR analysis was run with a
10 mm cryoprobe, at 120.degree. C., on Bruker AVANCE 400 MHz
spectrometer.
[0148] Two experiments were run to get the unsaturation: the
control and the double presaturation experiments. For the control
experiment, the data was processed with an exponential window
function with LB=1 Hz, and the baseline was corrected from 7 to -2
ppm. The signal from residual .sup.1H of TCE was set to 100, and
the integral I.sub.total from -0.5 to 3 ppm was used as the signal
from whole polymer in the control experiment. The "number of
CH.sub.2 group, NCH.sub.2," in the polymer was calculated as
follows in Equation 1A:
NCH.sub.2=I.sub.total/2 (Eqn. 1A).
[0149] For the double presaturation experiment, the data was
processed with an exponential window function with LB=1 Hz, and the
baseline was corrected from about 6.6 to 4.5 ppm. The signal from
residual .sup.1H of TCE was set to 100, and the corresponding
integrals for unsaturations (I.sub.vinylene, I.sub.trisubstituted,
I.sub.vinyl and I.sub.vinylidene) were integrated. It is well known
to use NMR spectroscopic methods for determining polyethylene
unsaturation, for example, see Busico, V., et al., Macromolecules,
2005, 38, 6988. The number of unsaturation unit for vinylene,
trisubstituted, vinyl and vinylidene were calculated as
follows:
N.sub.vinylene=I.sub.vinylene/2 (Eqn. 2A),
N.sub.trisubstituted=I.sub.trisubstitute (Eqn. .sup.3A),
N.sub.vinyl=I.sub.vinyl/2 (Eqn. 4A),
N.sub.vinylidene=I.sub.vinylidene/2 (Eqn. 5A).
[0150] The unsaturation units per 1,000 carbons, all polymer
carbons including backbone carbons and branch carbons, were
calculated as follows:
N.sub.vinylene/1000C=(N.sub.vinylene/NCH.sub.2)*1,000 (Eqn.
6A),
N.sub.trisubstituted/1,000C=(N.sub.trisubstituted/NCH.sub.2)*1,000
(Eqn. 7A),
N.sub.vinyl/1,000C=(N.sub.vinyl/NCH.sub.2)*1,000 (Eqn. 8A),
N.sub.vinylidene/1,000C=(N.sub.vinylidene/NCH.sub.2)*1,000 (Eqn.
9A),
[0151] The chemical shift reference was set at 6.0 ppm for the
.sup.1H signal from residual proton from TCE-d2. The control was
run with ZG pulse, NS=4, DS=12, SWH=10,000 Hz, AQ=1.64s, D1=14s.
The double presaturation experiment was run with a modified pulse
sequence, with O1P=1.354 ppm, O2P=0.960 ppm, PL9 =57 db, PL21=70
db, NS=100, DS=4, SWH=10,000 Hz, AQ=1.64s, D1=1 s (where D1 is the
presaturation time), D13=13s. Only the vinyl levels were reported
in Table 2 below.
.sup.13C NMR Method
[0152] Samples are prepared by adding approximately 3g of a 50/50
mixture of tetra-chloroethane-d2/orthodichlorobenzene, containing
0.025 M Cr(AcAc).sub.3, to a "0.25 g polymer sample" in a 10 mm NMR
tube. Oxygen is removed from the sample by purging the tube
headspace with nitrogen. The samples are 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 is
visually inspected to ensure homogeneity.
[0153] All data are collected using a Bruker 400 MHz spectrometer.
The data is acquired using a 6 second pulse repetition delay,
90-degree flip angles, and inverse gated decoupling with a sample
temperature of 120.degree. C. All measurements are made on
non-spinning samples in locked mode. Samples are allowed to
thermally equilibrate for 7 minutes prior to data acquisition. The
13C NMR chemical shifts were internally referenced to the EEE triad
at 30.0 ppm.
[0154] C13 NMR Comonomer Content: It is well known to use NMR
spectroscopic methods for determining polymer composition. ASTM D
5017-96; J. C. Randall et al., in "NMR and Macromolecules" ACS
Symposium series 247; J. C. Randall, Ed., Am. Chem. Soc.,
Washington, D.C., 1984, Ch. 9; and J. C. Randall in "Polymer
Sequence Determination", Academic Press, New York (1977) provide
general methods of polymer analysis by NMR spectroscopy.
Molecular Weighted Comonomer Distribution Index (MWCDI)
[0155] A GPC-IR, high temperature chromatographic system from
PolymerChar (Valencia, Spain) was equipped with a Precision
Detectors' (Amherst, Mass.) 2-angle laser light scattering detector
Model 2040, and an IR5 infra-red detector (GPC-IR) and a
4-capillary viscometer, both from PolymerChar. The "15-degree
angle" of the light scattering detector was used for calculation
purposes. Data collection was performed using PolymerChar
Instrument Control software and data collection interface. The
system was equipped with an on-line, solvent degas device and
pumping system from Agilent Technologies (Santa Clara, Calif.).
[0156] Injection temperature was controlled at 150 degrees Celsius.
The columns used, were four, 20-micron "Mixed-A" light scattering
columns from Polymer Laboratories (Shropshire, UK). The solvent was
1,2,4-trichlorobenzene. The samples were prepared at a
concentration of "0.1 grams of polymer in 50 milliliters of
solvent." The chromatographic solvent and the sample preparation
solvent each contained "200 ppm of butylated hydroxytoluene (BHT)."
Both solvent sources were nitrogen sparged. Ethylene-based polymer
samples were stirred gently, at 160 degrees Celsius, for three
hours. The injection volume was "200 microliters," and the flow
rate was "1 milliliters/minute."
[0157] 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/mole. These
standards were arranged in six "cocktail" mixtures, with at least a
decade of separation between individual molecular weights. The
standards were purchased from Polymer Laboratories (Shropshire UK).
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/mole, and at "0.050 grams in 50 milliliters of
solvent" for molecular weights less than 1,000,000 g/mole. The
polystyrene standards were dissolved at 80 degrees Celsius, with
gentle agitation, for 30 minutes. The narrow standards mixtures
were run first, and in order of decreasing "highest molecular
weight component," to minimize degradation. The polystyrene
standard peak molecular weights were converted to polyethylene
molecular weights using Equation 1B (as described in Williams and
Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)):
Mpolyethylene=A.times.(Mpolystyrene).sup.B (Eqn. 1B),
where M is the molecular weight, A has a value of approximately
0.40 and B is equal to 1.0. The A value was adjusted between 0.385
and 0.425 (depending upon specific column-set efficiency), such
that NBS 1475A (NIST) linear polyethylene weight-average molecular
weight corresponded to 52,000 g/mole, as calculated by Equation 3B,
below:
Mn ( LALS gpc ) = i = RV integration start i = RV integration end (
IR measurement channel i ) i = RV integration start i = RV
integration end ( IR measurement channel i M PE i ) ( Eqn . 2 B )
Mw ( LALS gpc ) = i = RV integration start i = RV integration end (
M PE i IR measurement channel i ) i = RV integration start i = RV
integration end ( IR measurement channel i ) ( Eqn . 3 B )
##EQU00003##
[0158] In Equations 2B and 3B, RV is column retention volume
(linearly-spaced), collected at "1 point per second." The IR is the
baseline-subtracted IR detector signal, in Volts, from the
measurement channel of the GPC instrument, and the M.sub.PE is the
polyethylene-equivalent MW determined from Equation 1B. Data
calculation were performed using "GPC One software (version
2.013H)" from PolymerChar.
[0159] A calibration for the IR5 detector ratios was performed
using at least ten ethylene-based polymer standards (polyethylene
homopolymer and ethylene/octene copolymers; narrow molecular weight
distribution and homogeneous comonomer distribution) of known short
chain branching (SCB) frequency (measured by the .sup.13C NMR
Method, as discussed above), ranging from homopolymer (0 SCB/1000
total C) to approximately 50 SCB/1000 total C, where total
C=carbons in backbone+carbons in branches. Each standard had a
weight-average molecular weight from 36,000 g/mole to 126,000
g/mole, as determined by the GPC-LALS processing method described
above. Each standard had a molecular weight distribution (Mw/Mn)
from 2.0 to 2.5, as determined by the GPC-LALS processing method
described above. Polymer properties for the SCB standards are shown
in Table A.
TABLE-US-00001 TABLE A "SCB" Standards SCB/1000 Wt % Comonomer IR5
Area ratio Total C Mw Mw/Mn 23.1 0.2411 28.9 37,300 2.22 14.0
0.2152 17.5 36,000 2.19 0.0 0.1809 0.0 38,400 2.20 35.9 0.2708 44.9
42,200 2.18 5.4 0.1959 6.8 37,400 2.16 8.6 0.2043 10.8 36,800 2.20
39.2 0.2770 49.0 125,600 2.22 1.1 0.1810 1.4 107,000 2.09 14.3
0.2161 17.9 103,600 2.20 9.4 0.2031 11.8 103,200 2.26
[0160] The "IR5 Area Ratio (or "IR5.sub.Methyl Channel
Area/IR5.sub.Measurement Channel Area")" of "the
baseline-subtracted area response of the IR5 methyl channel sensor"
to "the baseline-subtracted area response of IR5 measurement
channel sensor" (standard filters and filter wheel as supplied by
PolymerChar: Part Number IR5_FWM01 included as part of the GPC-IR
instrument) was calculated for each of the "SCB" standards. A
linear fit of the SCB frequency versus the "IR5 Area Ratio" was
constructed in the form of the following Equation 4B:
SCB/1000 total C=A.sub.0+[A.sub.1.times.(IR5.sub.Methyl Channel
Area/IR5.sub.Measurement Channel Area)] (Eqn. 4B),
where A.sub.0 is the "SCB/1000 total C" intercept at an "IR5 Area
Ratio" of zero, and A.sub.1 is the slope of the "SCB/1000 total C"
versus "IR5 Area Ratio" and represents the increase in the
"SCB/1000 total C" as a function of "IR5 Area Ratio."
[0161] A series of "linear baseline-subtracted chromatographic
heights" for the chromatogram generated by the "IR5 methyl channel
sensor" was established as a function of column elution volume, to
generate a baseline-corrected chromatogram (methyl channel). A
series of "linear baseline-subtracted chromatographic heights" for
the chromatogram generated by the "IR5 measurement channel" was
established as a function of column elution volume, to generate a
base-line-corrected chromatogram (measurement channel).
[0162] The "IR5 Height Ratio" of "the baseline-corrected
chromatogram (methyl channel)" to "the baseline-corrected
chromatogram (measurement channel)" was calculated at each column
elution volume index (each equally-spaced index, representing 1
data point per second at 1 ml/min elution) across the sample
integration bounds. The "IR5 Height Ratio" was multiplied by the
coefficient A.sub.1, and the coefficient A.sub.0 was added to this
result, to produce the predicted SCB frequency of the sample. The
result was converted into mole percent comonomer, as follows in
Equation 5B:
Mole Percent
Comonomer={SCB.sub.f/[SCB.sub.f+((1000-SCB.sub.f*Length of
comonomer)/2)]}*100 (Eqn. 5B),
where "SCB.sub.f" is the "SCB per 1000 total C" and the "Length of
comonomer"=8 for octene, 6 for hexene, and so forth.
[0163] Each elution volume index was converted to a molecular
weight value (Mw.sub.i) using the method of Williams and Ward
(described above; Eqn. 1B). The "Mole Percent Comonomer (y axis)"
was plotted as a function of Log(Mw.sub.i), and the slope was
calculated between Mw.sub.i of 15,000 and Mw.sub.i of 150,000
g/mole (end group corrections on chain ends were omitted for this
calculation). An EXCEL linear regression was used to calculate the
slope between, and including, Mw.sub.i from 15,000 to 150,000
g/mole. This slope is defined as the molecular weighted comonomer
distribution index (MWCDI=Molecular Weighted Comonomer Distribution
Index).
Representative Determination of MWCDI (Inventive First Composition
2)
[0164] A plot of the measured "SCB per 1000 total C (=SCB.sub.f)"
versus the observed "IR5 Area Ratio" of the SCB standards was
generated (see FIG. 1), and the intercept (A.sub.0) and slope
(A.sub.1) were determined. Here, A.sub.0=-90.246 SCB/1000 total C;
and A.sub.1=499.32 SCB/1000 total C.
[0165] The "IR5 Height Ratio" was determined for Inventive Example
2 (see integration shown in
[0166] FIG. 2). This height ratio (IR5 Height Ratio of Inventive
Example 2) was multiplied by the coefficient A.sub.1, and the
coefficient A.sub.0 was added to this result, to produce the
predicted SCB frequency of this example, at each elution volume
index, as described above (A.sub.0=-90.246 SCB/1000 total C; and
A.sub.1=499.32 SCB/1000 total C). The SCB.sub.f was plotted as a
function of polyethylene-equivalent molecular weight, as determined
using Equation 1B, as discussed above. See FIG. 3 (Log Mwi used as
the x-axis).
[0167] The SCB.sub.f was converted into "Mole Percent Comonomer"
via Equation 5B. The "Mole Percent Comonomer" was plotted as a
function of polyethylene-equivalent molecular weight, as determined
using Equation 1B, as discussed above. See FIG. 4 (Log Mwi used as
the x-axis). A linear fit was from Mwi of 15,000 g/mole to Mwi of
150,000 g/mole, yielding a slope of "2.27 mole percent comonomer x
mole/g." Thus, the MWCDI=2.27. An EXCEL linear regression was used
to calculate the slope between, and including, Mwi from 15,000 to
150,000 g/mole.
Film Testing Conditions
[0168] The following physical properties were measured on the films
produced (see experimental section).
[0169] 45.degree. Gloss: ASTM D-2457.
[0170] Clarity: ASTM: D-1746.
ASTM D1003 Total Haze
[0171] Samples measured for internal haze and overall (total) haze
were sampled and prepared according to ASTM D1003. Internal haze
was obtained via refractive index matching using mineral oil on
both sides of the films. A Hazeguard Plus (BYK-Gardner USA;
Columbia, MD.) was used for testing. Surface haze was determined as
the difference between total haze and internal haze. The total haze
was reported as the average of five measurements.
ASTM D1922 MD (Machine Direction) and CD (Cross Direction)
Elmendorf Tear Type B
[0172] The Elmendorf Tear test determines the average force to
propagate tearing through a specified length of plastic film or non
rigid sheeting, after the tear has been started, using an
Elmendorf-type tearing tester.
[0173] After film production from the sample to be tested, the film
was conditioned for at least 40 hours at 23.degree. C.
(+/-2.degree. C.) and 50% R. H (+/-5), as per ASTM standards.
Standard testing conditions were 23.degree. C. (+/-2.degree. C.)
and 50% R. H (+/-5), as per ASTM standards.
[0174] The force, in grams, required to propagate tearing across a
film or sheeting specimen was measured using a precisely calibrated
pendulum device. In the test, acting by gravity, the pendulum swung
through an arc, tearing the specimen from a precut slit. The
specimen was held on one side by the pendulum and on the other side
by a stationary member. The loss in energy by the pendulum was
indicated by a pointer or by an electronic scale. The scale
indication was a function of the force required to tear the
specimen.
[0175] The sample specimen geometry used in the Elmendorf tear test
was the `constant radius geometry` as specified in ASTM D1922.
Testing is typically carried out on specimens that have been cut
from both the film MD and CD directions. Prior to testing, the film
specimen thickness was measured at the sample center. A total of 15
specimens per film direction were tested, and the average tear
strength and average thickness reported. The average tear strength
was normalized to the average thickness.
ASTM D882 MD and CD, 1% and 2% Secant Modulus, Tensile Strength,
and Break Strain
[0176] The film MD (Machine Direction) and CD (Cross Direction)
secant modulus and tensile break strength (or tensile strength)
were measured with an Instron universal tester according to ASTM
D882-10. The reported secant modulus value was the average of five
measurements. The tensile break strength was determined using five
film samples in each direction, with each sample being "1
inch.times.6 inches" in size. The break strength is the tensile
load or force required to rupture or break a given material. It is
measured as pounds of force for each square inch (psi). The break
strain is the strain at which the material breaks and is measured
as length at break divided by original length multiplied by 100
(%).
Puncture Strength
[0177] The Puncture test determines the resistance of a film to the
penetration of a probe at a standard low rate, a single test
velocity. The puncture test method is based on ASTM D5748. After
film production, the film was conditioned for at least 40 hours at
23.degree. C. (+/-2.degree. C.) and 50% R. H (+/-5), as per ASTM
standards. Standard testing conditions were 23.degree. C.
(+/-2.degree. C.) and 50% R. H (+/-5), as per ASTM standards.
Puncture was measured on a tensile testing machine. Square
specimens were cut from a sheet to a size of "6 inches by 6
inches." The specimen was clamped in a "4 inch diameter" circular
specimen holder, and a puncture probe was pushed into the centre of
the clamped film at a cross head speed of 10 inches/minute. The
internal test method follows ASTM D5748, with one modification. It
deviated from the ASTM D5748 method, in that the probe used was a
"0.5 inch diameter" polished steel ball on a "0.25 inch" support
rod (rather than the 0.75 inch diameter, pear shaped probe
specified in D5748).
[0178] There was a "7.7 inch" maximum travel length to prevent
damage to the test fixture. There was no gauge length; prior to
testing, the probe is as close as possible to, but not touching the
specimen.
[0179] A single thickness measurement was made in the centre of the
specimen. For each specimen, the maximum force, the force at break,
the penetration distance, and the energy to break were determined.
A total of five specimens were tested to determine an average
puncture value. The puncture probe was cleaned using a "Kim-wipe"
after each specimen.
ASTM D1709 Dart Drop
[0180] The film Dart Drop test determines the energy that causes a
plastic film to fail, under specified conditions of impact by a
free falling dart. The test result is the energy, expressed in
terms of the weight of the missile falling from a specified height,
which would result in the failure of 50% of the specimens
tested.
[0181] After the film was produced, it was conditioned for at least
40 hours at 23.degree. C. (+/-2.degree. C.) and 50% R. H (+/-5), as
per ASTM standards. Standard testing conditions are 23.degree. C.
(+/-2.degree. C.) and 50% R. H (+/-5), as per ASTM standards.
[0182] The test result was reported as either by Method A, which
uses a 1.5'' diameter dart head and 26'' drop height, or by Method
B, which uses a 2'' diameter dart head and 60'' drop height. The
sample thickness was measured at the sample center, and the sample
then clamped by an annular specimen holder with an inside diameter
of 5 inches. The dart was loaded above the center of the sample,
and released by either a pneumatic or electromagnetic
mechanism.
[0183] Testing was carried out according to the `staircase` method.
If the sample failed, a new sample was tested with the weight of
the dart reduced by a known and fixed amount. If the sample did not
fail, a new sample was tested with the weight of the dart increased
by a known amount. After 20 specimens had been tested, the number
of failures was determined. If this number was 10, then the test is
complete. If the number was less than 10, then the testing
continued, until 10 failures had been recorded. If the number was
greater than 10, testing continued, until the total of non-failures
was 10. The Dart Drop strength was determined from these data, as
per ASTM D1709, and expressed in grams, as either the Dart Drop
Impact of Type A or Type B. In some cases, the sample Dart Drop
Impact strength may lie between A and B. In these cases, it was not
possible to obtain a quantitative dart value.
Water Vapor Transmission Rate (WVTR)
[0184] Water Vapor Transmission Rate (or WVTR) is the absolute
transmission rate. WVTR was determined according to ASTM D-6701 and
is reported in units of g/m.sup.2.sub./day.
EXAMPLES
[0185] The following examples illustrate the present invention, but
are not intended to limit the scope of the invention.
Example 1
Inventive First Compositions 1, 2 and 3
[0186] Inventive first compositions 1, 2 and 3, each contain two
ethylene-octene copolymers. Each composition was prepared, via
solution polymerization, in a dual series loop reactor system
according to U.S. Pat. No. 5,977,251 (see FIG. 2 of this patent),
in the presence of a first catalyst system, as described below, in
the first reactor, and a second catalyst system, as described
below, in the second reactor.
[0187] The first catalyst system comprised a
bis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethy-
l)-methylene-1,2-cyclohexanediylhafnium (IV) dimethyl, represented
by the following formula (CAT 1):
##STR00005##
[0188] The molar ratios of the metal of CAT 1, added to the
polymerization reactor, in-situ, to that of Cocat1 (modified methyl
aluminoxane), or Cocat2 (bis(hydrogenated tallow alkyl)methyl,
tetrakis(pentafluorophenyl)borate(1-) amine), are shown in Table
1.
[0189] The second catalyst system comprised a Ziegler-Natta type
catalyst (CAT 2). The heterogeneous Ziegler-Natta type
catalyst-premix was prepared substantially according to U.S. Pat.
No. 4,612,300, by sequentially adding to a volume of ISOPAR E, a
slurry of anhydrous magnesium chloride in ISOPAR E, a solution of
EtAlCl.sub.2 in heptane, and a solution of Ti(O-iPr).sub.4 in
heptane, to yield a composition containing a magnesium
concentration of 0.20M, and a ratio of Mg/Al/Ti of 40/12.5/3. An
aliquot of this composition was further diluted with ISOPAR-E to
yield a final concentration of 500 ppm Ti in the slurry. While
being fed to, and prior to entry into, the polymerization reactor,
the catalyst premix was contacted with a dilute solution of
Et.sub.3Al, in themolar Al to Ti ratio specified in Table 1, to
give the active catalyst.
[0190] The polymerization conditions for the inventive first
compositions 1, 2 and 3 are reported in Table 1. As seen in Table
1, Cocat. 1 (modified methyl aluminoxane (MMAO)); and Cocat. 2
(bis(hydrogenated tallow alkyl)methyl,
tetrakis(pentafluorophenyl)borate(1-) amine) were each used as a
cocatalyst for CAT 1. Additional properties of the inventive
compositions 1, 2 and 3 were measured, and are reported in Table 2.
The GPC MWD profiles, and corresponding comonomer distribution
overlays, are shown in FIGS. 8-10. Each polymer composition was
stabilized with minor (ppm) amounts of stabilizers.
Comparative First Compositions A and B
[0191] Comparative compositions A and B, each contain two
ethylene-octene copolymers, and each was prepared, via solution
polymerization, in a dual loop reactor system, in the presence of a
first catalyst system, as described below, in the first reactor,
and a second catalyst system, as described below, in the second
reactor. The first catalyst system comprised titanium,
[N--(1,1-dimethylethyl)-1,1-dimethyl-1-[(1,2,3,3a,8a-.eta.)-1,5,6,7-tetra-
hydro-2-methyl-s-indacen-1-yl]silanaminato(2-)-.kappa.N][(1,2,3,4-.eta.)-1-
,3-pentadiene]-(CAT 3, a constrained geometry catalyst). The second
catalyst system comprised the Ziegler-Natta premix (CAT 2), as
discussed above.
[0192] The polymerization conditions for comparative compositions A
and B are reported in Table 1. As seen in Table 1, Cocat. 1
(modified methyl aluminoxane (MMAO)) and Cocat. 2 (bis(hydrogenated
tallow alkyl)methyl, tetrakis(pentafluorophenyl)borate(1-) amine)
were each used as cocatalyst for CAT 3. Additional properties of
the comparative compositions A and B were measured, and are
reported in Table 2. The GPC MWD profiles, and corresponding
comonomer distribution overlays, are shown in FIGS. 8 and 9. Each
polymer composition was stabilized with minor (ppm) amounts of
stabilizers.
Comparative C (First Composition)
[0193] Comparative C is an ethylene-hexene copolymer composition,
commercially available under the commercial designation EXCEED
1018CA from EXXONMOBIL Chemical Company, and having a density of
approximately 0.918 g/cm.sup.3, a melt index (I.sub.2 or I2),
measured at 190.degree. C. and 2.16 kg, of approximately 1.0 g/10
minutes. Additional properties of the comparative example C were
measured, and are reported in Table 2. The GPC MWD profile, and
corresponding comonomer distribution overlay, is shown in FIG.
8.
Comparative D (First Composition)
[0194] Comparative D is an ethylene-octene copolymer composition,
provided by The Dow Chemical Company, under the commercial
designation ELITE 5230G, and having a density of approximately
0.916 g/cm.sup.3, a melt index (I.sub.2 or I2), measured at
190.degree. C. and 2.16 kg, of approximately 4.0 g/10 minutes.
Additional properties of the comparative example D were measured,
and are reported in Table 2. The GPC MWD profile, and corresponding
comonomer distribution overlay, is shown in FIG. 10.
TABLE-US-00002 TABLE 1 Polymerization Conditions (Rx1 = reactor 1;
Rx2 = reactor 2) Sample # Units Inv. First 1 Inv. First 2 Inv.
First 3 Comp. First A Comp. First B Reactor Configuration Dual
Series Dual Series Dual Series Dual Series Dual Series Comonomer
1-octene 1-octene 1-octene 1-octene 1-octene REACTOR FEEDS First
Reactor Total Solvent lb/hr 1122 1057 1177 958 1061 Flow First
Reactor Total Ethylene lb/hr 190 175 269 184 187 Flow First Reactor
Total lb/hr 74 48 118 97 58 Comonomer Flow First Reactor Hydrogen
Feed SCCM 6827 5017 22848 525 857 Flow Second Reactor Total Solvent
lb/hr 384 451 421 494 561 Flow Second Reactor Total lb/hr 173 204
155 182 216 Ethylene Flow Second Reactor Total lb/hr 12 8 22 50 17
Comonomer Flow Second Reactor Hydrogen SCCM 298 99 100 2446 3829
Feed Flow REACTION First Reactor Control .degree. C. 140 150 143
145 135 Temperature First Reactor Ethylene % 86.7 90.5 72.7 69.4
77.7 Conversion First Reactor Viscosity cP 2400 2315 824 891 1318
Second Reactor Control .degree. C. 195 195 190 190 195 Temperature
Second Reactor Ethylene % 87.1 86 87.8 89.2 88.8 Conversion Second
Reactor Viscosity cP 869 876 264 892 848 CATALYST First Reactor
Catalyst type CAT 1 CAT 1 CAT 1 CAT 3 CAT 3 First Reactor Catalyst
g 3,681,068 2,333,579 481,051 2,984,071 2,653,724 Efficiency
polymer per g catalyst metal First Reactor Cocatalyst Ratio 1.3 1.8
1.2 1.2 1.5 (Cocat. 2) to Catalyst Metal Molar Ratio First Reactor
Cocatalyst Ratio 20 100 5 15 25 (Cocat. 1) to Catalyst Metal Molar
Ratio Second Reactor Catalyst g 404,385 469,511 176,500 561,063
390,994 Efficiency polymer per g catalyst metal Second Reactor Al
to Ti Ratio 4.0 4.0 1.2 4.0 4.0 Molar Ratio * solvent = ISOPAR
E
TABLE-US-00003 TABLE 2 Properties of Inventive and Comparative
Compositions Comp. Comp. Comp. Comp. Unit Inv. First 1 Inv. First 2
Inv. First 3 First A First B First C First D Density g/cc 0.9174
0.9245 0.9148 0.9162 0.9253 0.9191 0.9158 I.sub.2 g/10 min 0.83
0.87 3.91 0.93 0.80 0.95 4.05 I.sub.10/I.sub.2 7.7 8.0 7.3 8.2 8.4
6.0 7.0 7.0 - 7.1 7.1 6.3 7.0 7.1 7.0 6.3 1.2 .times. log(I2) Mn
(conv.gpc) g/mol 32,973 33,580 20,244 33,950 34,626 45,645 26,355
Mw (conv.gpc) 117,553 117,172 78,820 111,621 112,688 109,931 76,118
Mz (conv.gpc) 270,191 277,755 186,520 258,547 254,301 197,425
155,254 Mw/Mn 3.57 3.49 3.89 3.29 3.25 2.41 2.89 (conv.gpc) Mz/Mw
2.30 2.37 2.37 2.32 2.26 1.80 2.04 (conv.gpc) Eta* (0.1 rad/s) Pa s
9,496 11,231 1,997 10,342 11,929 6,975 2,057 Eta* (1.0 rad/s) Pa s
7,693 8,455 1,920 7,313 7,942 6,472 1,908 Eta* (10 rad/s) Pa s
4,706 4,977 1,527 4,337 4,586 5,071 1,473 Eta* (100 rad/s) Pa s
1,778 1,893 792 1,769 1,873 2,415 834 Eta* 0.1/ 5.34 5.93 2.52 5.85
6.37 2.89 2.47 Eta* 100 Eta zero Pa s 11,210 13,947 2,142 12,994
15,661 7,748 2,176 MWCDI 2.64 2.27 1.56 0.65 0.79 -0.06 -0.54
Vinyls Per 1000 134 179 115 157 148 69 56 total Carbons ZSVR 1.53
1.92 1.25 2.13 2.49 1.35 1.45
Example 2
Inventive Compositions 4 and 5
[0195] Inventive compositions 4 and 5 each contain an
ethylene-octene copolymer. Inventive compositions 4 and 5 were
prepared in the same manner and using the same catalyst system as
inventive compositions 1-3, with the exception of the
polymerization conditions which are reported in Table 3.
TABLE-US-00004 TABLE 3 Polymerization Conditions (Rx1 = reactor 1;
Rx2 = reactor 2) Sample # Units Inv. Comp. 4 Inv. Comp. 5 Reactor
Configuration Dual Series Dual Series Comonomer 1-octene 1-octene
REACTOR FEEDS First Reactor Total Solvent lb/hr 1323 957 Flow First
Reactor Total Ethylene lb/hr 228 200 Flow First Reactor Total lb/hr
86 71 Comonomer Flow First Reactor Hydrogen Feed SCCM 6379 4578
Flow Second Reactor Total Solvent lb/hr 525 464 Flow Second Reactor
Total lb/hr 201 211 Ethylene Flow Second Reactor Total lb/hr 12 13
Comonomer Flow Second Reactor Hydrogen SCCM 4392 2233 Feed Flow
REACTION First Reactor Control .degree. C. 165 165 Temperature
First Reactor Ethylene % 89.0 92.0 Conversion First Reactor
Viscosity cP 402 1121 Second Reactor Control .degree. C. 195 195
Temperature Second Reactor Ethylene % 86.2 84.7 Conversion Second
Reactor Viscosity cP 219 524.7 CATALYST First Reactor Catalyst type
CAT 1 CAT 1 First Reactor Catalyst g 617060 1204000 Efficiency
polymer per g catalyst metal First Reactor Cocatalyst Ratio 1.2 1.2
(Cocat. 2) to Catalyst Metal Molar Ratio First Reactor Cocatalyst
Ratio 18.0 50.0 (Cocat. 1) to Catalyst Metal Molar Ratio Second
Reactor Catalyst g 354157 422627 Efficiency polymer per g catalyst
metal Second Reactor Al to Ti Ratio 4.0 4.0 Molar Ratio * solvent =
ISOPAR E
[0196] A breathable film was formed from Inventive Composition 4.
Inventive Composition 4 was compounded using a Farrel continuous
mixer with underwater pelletization. The amounts of the components
that were compounded into pellets are shown in Table 4:
TABLE-US-00005 TABLE 4 Component Weight Percent Inventive
Composition 4 50% Calcium Carbonate 45% LDPE 5%
The Calcium Carbonate was Imerys FilmLink.RTM. 500, which is
commercially available from Imerys Carbonates. The LDPE was DOW.TM.
LDPE 640I, which is commercially available from The Dow Chemical
Company.
[0197] Films were fabricated on a 5 layer Egan Davis Standard
coextrusion cast film line. The cast line consisted of three 21/2''
and two 2'' 30:1 L/D Egan Davis Standard MAC extruders which are
air cooled. All extruders had moderate work DSB (Davis Standard
Barrier) type screws. Equipment specifications included a Cloeren 5
layer dual plane feed block and a Cloeren 36'' Epich II autogage
5.1 die. The primary chill roll had a matte finish and was 40''
outer diameter (O.D.).times.40'' long with a 30-40 RMS surface
finish for improved release characteristics. The secondary chill
roll was 20'' O.D..times.40'' long with a 2-4 RMS surface for
improved web tracking. Both the primary and secondary chill rolls
had chilled water circulating through them to provide quenching. A
Scantech X-ray gauge sensor for gauge thickness and automatic gauge
control was available if needed. Films were fabricated at following
conditions: Melt temperature=400.degree. F.; Temperature profile
(B1 300.degree. F.,
[0198] B2 400.degree. F., B3-5 400.degree. F., Screen 400.degree.
F., Adaptor 400.degree. F., Die all zones 400.degree. F.),
Throughput rate=200-270 lb/hr, Chill roll temperature=70.degree.
F., Cast roll temperature=70.degree. F., Air knife=7.4'' H.sub.2O,
Vacuum box=OFF, Die gap=20-25 mil, and Air gap=4''.
[0199] Each film was oriented using a Machine Direction Orientation
(MDO) System, such as those available from Marshall and Williams
Plastics and Parkinson Technologies, Inc. The film was oriented in
the machine direction using a series of rollers at the same or
different speeds to impart orientation. The film roll width on the
feed roller was 24 inches with a thickness of 2.0 mil. The rollers
were kept at the following temperatures: preheat roller 1
(165.degree. F.), preheat roller 2 (165.degree. F.), slow draw
roller (185.degree. F.), fast draw roller (175.degree. F.), anneal
roller (165.degree. F.) and cold roller (140.degree. F.). The speed
of the slow draw roll was 5.1 feet per minute, and the speed of the
fast draw roll was 19.1 feet per minute to provide a draw ratio of
3.75. The exit width of the film roll was 21.6 inches with a
thickness of 0.7-0.8 mil. The temperature profile used in the MDO
System is shown in Table 5:
TABLE-US-00006 TABLE 5 Preheat 1 Preheat 2 Slow Draw Fast Draw
Anneal Cool 165.degree. F. 165.degree. F. 185.degree. F.
175.degree. F. 165.degree. F. 140.degree. F.
[0200] Various film properties of the oriented film were measured.
The number of samples, average values, and standard deviations are
shown in Table 6:
TABLE-US-00007 TABLE 6 # of Average .+-. Property Samples Std. Dev.
Elmendorf Tear, Machine Direction (gram 15 3.6 .+-. 1.2 force)
Elmendor Tear, Cross Direction (gram force) 15 525 .+-. 81 Break
Stress, Machine Direction (psi) 5 4835 .+-. 1993 Break Stress,
Cross Direction (psi) 5 954 .+-. 41 Break Strain, Machine Direction
(%) 5 51 .+-. 9 Break Strain, Cross Direction (%) 5 493 .+-. 25
Puncture Strength (ft*lb/in.sup.3) 5 7.6 .+-. 1.9 WVTR
(g/m.sup.2/day) 2 2350 .+-. 44
Example 3
[0201] The stretch windows of Inventive Composition 4 and
DOWLEX.TM. 2047G Polyethylene resin (commercially available from
The Dow Chemical Company) were determined using MDO conditions as
described above with modification of the roll temperatures as shown
in Table 7:
TABLE-US-00008 TABLE 7 Preheat 1 Preheat 2 Slow Draw Fast Draw
Anneal Cool 165.degree. F. 185.degree. F. 205.degree. F.
195.degree. F. 165.degree. F. 140.degree. F.
The stretch windows are shown in Table 8:
TABLE-US-00009 TABLE 8 Resin Minimum Draw Ratio Maximum Draw Ratio
Inventive Composition 4 3.25 5.75 DOWLEX .TM. 2047G 3.50 5.25
The minimum draw ratio was the draw ratio where haze variations
(tiger striping) were visually absent from the film, and the
maximum draw ratio was the draw ratio where pinholes or breaks in
the film web were observed.
Example 4
Inventive Compositions 6 and 7
[0202] Inventive compositions 6 and 7 each contain an
ethylene-octene copolymer. Inventive compositions 6 and 7 were
prepared in the same manner and using the same catalyst system as
inventive compositions 1-3, with the exception of the
polymerization conditions which are reported in Table 9.
TABLE-US-00010 TABLE 9 Polymerization Conditions (Rx1 = reactor 1;
Rx2 = reactor 2) Sample # Units Inv. Comp. 6 Inv. Comp. 7 Reactor
Configuration Dual Series Dual Series Comonomer 1-octene 1-octene
REACTOR FEEDS First Reactor Total Solvent lb/hr 965 724 Flow First
Reactor Total Ethylene lb/hr 201 151 Flow First Reactor Total lb/hr
49 23 Comonomer Flow First Reactor Hydrogen Feed SCCM 6092 4057
Flow Second Reactor Total Solvent lb/hr 492 641 Flow Second Reactor
Total lb/hr 223 291 Ethylene Flow Second Reactor Total lb/hr 10 8
Comonomer Flow Second Reactor Hydrogen SCCM 1786 4002 Feed Flow
REACTION First Reactor Control .degree. C. 160 160 Temperature
First Reactor Ethylene % 91.6 93.0 Conversion First Reactor
Viscosity cP 1620 2186 Second Reactor Control .degree. C. 195 195
Temperature Second Reactor Ethylene % 85.8 88.3 Conversion Second
Reactor Viscosity cP 579.2 775.7 CATALYST First Reactor Catalyst
type CAT 1 CAT 1 First Reactor Catalyst g 2610844 2461080
Efficiency polymer per g catalyst metal First Reactor Cocatalyst
Ratio 1.3 1.2 (Cocat. 2) to Catalyst Metal Molar Ratio First
Reactor Cocatalyst Ratio 50.0 50.0 (Cocat. 1) to Catalyst Metal
Molar Ratio Second Reactor Catalyst g 622016 741104 Efficiency
polymer per g catalyst metal Second Reactor Al to Ti Ratio 4.0 4.0
Molar Ratio
[0203] Properties of the Inventive Compositions were measured, and
are reported in Table 10.
TABLE-US-00011 TABLE 10 Properties of Inventive Compositions Unit
Inv. Comp. 6 Inv. Comp. 7 Density g/cc 0.9244 0.9351 I.sub.2 g/10
min 2.31 2.61 I.sub.10/I.sub.2 7.5 7.5 7.0 - 6.6 6.5 1.2 .times.
log(I2) Mn (conv. gpc) g/mol 30,905 29,269 Mw (conv. gpc) g/mol
93,984 88,988 Mz (conv. gpc) g/mol 223,635 204,901 Mw/Mn 3.04 3.04
(conv. gpc) Mz/Mw 2.38 2.30 (conv. gpc) Eta* (0.1 rad/s) Pa s 3,876
3,308 Eta* (1.0 rad/s) Pa s 3,356 2,869 Eta* (10 rad/s) Pa s 2,337
2,028 Eta* (100 rad/s) Pa s 1,107 1,000 Eta*0.1/ 3.50 3.31 Eta*100
MWCDI 1.80 1.23
Breathable films can be formed from Inventive Compositions 6 and
7.
* * * * *