U.S. patent application number 12/065215 was filed with the patent office on 2009-03-12 for high-density polyethylene compositions, method of making the same, wire and cable jackets made therefrom, and method of making such wire and cable jackets.
Invention is credited to Chester J. Kmiec, William J. Michie, JR..
Application Number | 20090068429 12/065215 |
Document ID | / |
Family ID | 38596204 |
Filed Date | 2009-03-12 |
United States Patent
Application |
20090068429 |
Kind Code |
A1 |
Kmiec; Chester J. ; et
al. |
March 12, 2009 |
HIGH-DENSITY POLYETHYLENE COMPOSITIONS, METHOD OF MAKING THE SAME,
WIRE AND CABLE JACKETS MADE THEREFROM, AND METHOD OF MAKING SUCH
WIRE AND CABLE JACKETS
Abstract
The instant invention is a high-density polyethylene
composition, method of producing the same, wire and cable jackets
made therefrom, and method of making such wire and cable jackets.
The high-density polyethylene composition of the instant invention
includes a first component, and a second component. The first
component is a high molecular weight ethylene alpha-olefin
copolymer having a density in the range of 0.915 to 0.940
g/cm.sup.3, and a melt index (I.sub.21.6) in the range of 0.5 to 10
g/10 minutes. The second component is a low molecular weight
ethylene polymer having a density in the range of 0.965 to 0.980
g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes. The high-density polyethylene composition has a melt
index (I.sub.2) of at least 1, a density in the range of 0.950 to
0.960 g/cm.sup.3, and g' of equal or greater than 1. The method of
producing a high-density polyethylene composition includes the
following steps: (1) introducing ethylene, and one or more
alpha-olefin comonomers into a first reactor; (2) (co)polymerizing
the ethylene in the presence of one or more alpha-olefin comonomers
in the first reactor thereby producing a first component, wherein
the first component being a high molecular weight ethylene
alpha-olefin copolymer having a density in the range of 0.915 to
0.940 g/cm.sup.3, and a melt index (I.sub.21.6) in the range of 0.5
to 10 g/10 minutes; (3) introducing the first component and
additional ethylene into a second reactor; (4) polymerizing the
additional ethylene in the second reactor thereby producing a
second component, wherein the second component being a low
molecular weight ethylene polymer having a density in the range of
0.965 to 0.980 g/cm.sup.3, and a melt index (I.sub.2) in the range
of 50 to 1500 g/10 minutes; and (5) thereby producing the
high-density polyethylene composition, wherein the high-density
polyethylene composition having a melt index (I.sub.2) of at least
1, a density in the range of 0.950 to 0.960 g/cm.sup.3, and g' of
equal or greater than 1. The wire and cable jackets according to
instant invention comprise the above-described inventive
high-density polyethylene composition, and such wire and cable
jackets may be made via extrusion.
Inventors: |
Kmiec; Chester J.;
(Phillipsburg, NJ) ; Michie, JR.; William J.;
(Missouri City, TX) |
Correspondence
Address: |
The Dow Chemical Company
Intellectual Property Section, P.O. Box 1967
Midland
MI
48641-1967
US
|
Family ID: |
38596204 |
Appl. No.: |
12/065215 |
Filed: |
May 2, 2007 |
PCT Filed: |
May 2, 2007 |
PCT NO: |
PCT/US07/10796 |
371 Date: |
February 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60796809 |
May 2, 2006 |
|
|
|
Current U.S.
Class: |
428/218 ;
428/341 |
Current CPC
Class: |
Y10T 428/273 20150115;
C08L 23/0815 20130101; C08L 2203/10 20130101; C08L 23/08 20130101;
C08L 23/06 20130101; C08L 23/04 20130101; C08L 23/0815 20130101;
C08L 23/04 20130101; Y10T 428/24992 20150115; C08L 2666/06
20130101; C08L 23/06 20130101; C08L 2666/06 20130101; C08L 2666/06
20130101 |
Class at
Publication: |
428/218 ;
428/341 |
International
Class: |
B32B 27/08 20060101
B32B027/08; B32B 7/02 20060101 B32B007/02 |
Claims
1. A power or communication cable jacket comprising: an outer
sheath layer comprising: a high-density polyethylene composition
comprising: a first component, said first component being a high
molecular weight ethylene alpha-olefin copolymer having a density
in the range of 0.915 to 0.940 g/cm.sup.3, and a melt index
(I.sub.21.6) in the range of 0.5 to 10 g/10 minutes; and a second
component, said second component being a low molecular weight
ethylene polymer having a density in the range of 0.965 to 0.980
g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes; wherein said high-density polyethylene composition
having a melt index (I.sub.2) of at least 1 g/10 minutes, a density
in the range of 0.940 to 0.960 g/cm.sup.3, and g' of equal or
greater than 1.
2. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having a density
in the range of 0.950 to 0.960 g/cm.sup.3.
3. The power or communication cable jacket according to claim 1,
wherein said first component having a density in the range of 0.920
to 0.940 g/cm.sup.3.
4. The power or communication cable jacket according to claim 1,
wherein said power or communication cable jacket having an average
smoothness of equal or less than 18 micro-inches.
5. The power or communication cable jacket according to claim 1,
wherein said power or communication cable jacket having an average
surface smoothness of equal or less than 15 micro-inches.
6. The power or communication cable jacket according to claim 1,
wherein said power or communication cable jacket having shrink
on-wire after at least 24 hours of equal or less than 1.3
percent.
7. The power or communication cable jacket according to claim 1,
wherein said power or communication cable jacket having shrink back
off-wire after at least 24 hours of equal or less than 3.39
percent.
8. The power or communication cable jacket according to claim 1,
wherein said first component having a density in the range of 0.921
to 0.936 g/cm.sup.3.
9. The power or communication cable jacket according to claim 1,
wherein said first component having a melt index (I.sub.21.6) in
the range of 1 to 7 g/10 minutes.
10. The power or communication cable jacket according to claim 1,
wherein said first component having a melt index (I.sub.21.6) in
the range of 1.3 to 5 g/10 minutes.
11. The power or communication cable jacket according to claim 1,
wherein said second component having a density in the range of
0.970 to 0.975 g/cm.sup.3.
12. The power or communication cable jacket according to claim 1,
wherein said second component having a melt index (I.sub.2) in the
range of 100 to 1500 g/10 minutes.
13. The power or communication cable jacket according to claim 1,
wherein said second component having a melt index (I.sub.2) in the
range of 200 to 1500 g/10 minutes.
14. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having a melt
index (I.sub.2) in the range of 1 to 2 g/10 minutes.
15. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having a melt
index (I.sub.2) of at least 2 g/10 minutes.
16. The power or communication cable jacket according to claim 1,
wherein said first component having a molecular weight in the range
of 150,000 to 375,000.
17. The power or communication cable jacket according to claim 1,
wherein said second component having a molecular weight in the
range of 12,000 to 40,000.
18. The power or communication cable jacket according to claim 1,
wherein said first component having a density in the range of 0.921
to 0.936 g/cm.sup.3, and a melt index (I.sub.21.6) in the range of
1.3 to 5 g/10 minutes; wherein said second component having a
density in the range of 0.970 to 0.975 g/cm.sup.3, and a melt index
(I.sub.2) in the range of 200 to 1500 g/10 minutes.
19. The power or communication cable jacket according to claim 1,
wherein said first component being substantially free of any long
chain branching, and said second component being substantially free
of any long chain branching.
20. The power or communication cable jacket according to claim 14,
wherein said high-density polyethylene composition being
substantially free of any long chain branching.
21. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having a single
ATREF temperature peak, wherein said ATREF temperature peak having
a temperature peak maximum between 90.degree. C. to 105.degree. C.
wherein said high-density polyethylene composition having a
calculated high density fraction in the range of 20 percent to 50
percent, said calculated high density fraction being defined as
[(2).times.(the weight ratio of the high-density polyethylene that
elutes in ATREF-DV at temperatures greater than or equal to said
temperature peak maximum)], wherein said high-density polyethylene
composition having a relative minimum in the log of the relative
viscosity average molecular weight at about 90.degree. C. in
ATRF-DV; wherein said high-density polyethylene composition having
a regression slop of the log of the relative viscosity average
molecular weight versus the ATREF-DV viscosity versus temperature
plot of less than about 0, said elution temperature measured
between 70.degree. C. to 90.degree. C.
22. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having a
comonomer content in weight percent of equal or greater that
[(-228.41*density of said high-density polyethylene
composition)+219.36)]*[1(weight percent)/(g/cm.sup.3)], wherein the
density being measured in g/cm.sup.3.
23. The power or communication cable jacket according to claim 1,
wherein said high-density polyethylene composition having an ATREF
high-density fraction in percent of equal or less than
[(2750*density of the high-density polyethylene
composition)-2552.2]*[1(percent)/(g/cm.sup.3)], where the density
being measured in g/cm.sup.3.
24. A method of making a power or communication cable jacket
comprising the steps of: providing a high-density polyethylene
composition comprising; a first component, said first component
being a high molecular weight ethylene alpha-olefin copolymer
having a density in the range of 0.915 to 0.940 g/cm.sup.3, and a
melt index (I.sub.21.6) in the range of 0.5 to 10 g/10 minutes; and
a second component, said second component being a low molecular
weight ethylene polymer having a density in the range of 0.965 to
0.980 g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to
1500 g/10 minutes; wherein said high-density polyethylene
composition having a melt index (I.sub.2) of at least 1 .mu.l 0
minutes, a density in the range of 0.940 to 0.960 g/cm.sup.3, and
g' of equal or greater than 1; extruding said high-density
polyethylene composition over a power or communication cable;
thereby forming said power or communication cable jacket.
25. The method of making a power or communication cable jacket
composition according to claim 24, wherein said high-density
polyethylene composition being extruded over a power or
communication cable at a rate of at least 200 ft/minute.
26. The method of making a power or communication cable jacket
composition according to claim 25, wherein said power or
communication cable jacket having an average smoothness of equal or
less than 18 micro-inches.
27. The method of making a power or communication cable jacket
composition according to claim 25, wherein said power or
communication cable jacket having an average surface smoothness of
equal or less than 15 micro-inches.
28. The method of making a power or communication cable jacket
composition according to claim 25, wherein said power or
communication cable jacket having shrink on-wire after at least 24
hours of equal or less than 1.3 percent.
29. The power or communication cable jacket according to claim 25,
wherein said power or communication cable jacket having shrink back
off-wire after at least 24 hours of equal or less than 3.39
percent.
30. The method of making a power or communication cable jacket
composition according to claim 24, wherein said high-density
polyethylene composition being extruded over a power or
communication cable at a rate of at least 300 ft/minute.
31. The method of making a power or communication cable jacket
composition according to claim 30, wherein said power or
communication cable jacket having an average smoothness of equal or
less than 18 micro-inches.
32. The method of making a power or communication cable jacket
composition according to claim 30, wherein said power or
communication cable jacket having an average surface smoothness of
equal or less than 15 micro-inches.
33. The method of making a power or communication cable jacket
composition according to claim 30, wherein said power or
communication cable jacket having shrink on-wire after at least 24
hours of equal or less than 1.3 percent.
34. The power or communication cable jacket according to claim 30,
wherein said power or communication cable jacket having shrink back
off-wire after at least 24 hours of equal or less than 3.39
percent.
35. The method of making a power or communication cable jacket
composition according to claim 34, wherein said first component
having a density in the range of 0.920 to 0.940 g/cm.sup.3.
36. The method of making a power or communication cable jacket
composition according to claim 34, wherein said first component
having a density in the range of 0.921 to 0.936 g/cm.sup.3.
37. The method of making a power or communication cable jacket
composition according to claim 34, wherein said first component
having a melt index (I.sub.21.6) in the range of 1 to 7 g/10
minutes.
38. The method of making a power or communication cable jacket
composition according to claim 34, wherein said first component
having a melt index (I.sub.21.6) in the range of 1.3 to 5 g/10
minutes.
39. The method of making a power or communication cable jacket
composition according to claim 34, wherein said second component
having a density in the range of 0.970 to 0.975 g/cm.sup.3.
40. The method of making a power or communication cable jacket
composition according to claim 34, wherein said second component
having a melt index (I.sub.2) in the range of 100 to 1500 g/10
minutes.
41. The method of making a power or communication cable jacket
composition according to claim 34, wherein said second component
having a melt index (I.sub.2) in the range of 200 to 1500 g/10
minutes.
42. The method of making a power or communication cable jacket
according to claim 34, wherein said high-density polyethylene
composition having a melt index (I.sub.2) in the range of 1 to 2
g/10 minutes.
43. The method of making a power or communication cable jacket
according to claim 34, wherein said high-density polyethylene
composition having a melt index (I.sub.2) of at least 2 g/10
minutes.
44. The method of making a power or communication cable jacket
according to claim 34, wherein said first component having a
molecular weight in the range of 150,000 to 375,000.
45. The method of making a power or communication cable jacket
according to claim 34, wherein said second component having a
molecular weight in the range of 12,000 to 40,000.
46. The method of making a power or communication cable jacket
according to claim 34, wherein said first component having a
density in the range of 0.921 to 0.936 g/cm.sup.3, and a melt index
(I.sub.21.6) in the range of 1.3 to 5 g/10 minutes; wherein said
second component having a density in the range of 0.970 to 0.975
g/cm.sup.3, and a melt index (I.sub.2) in the range of 200 to 1500
g/10 minutes.
47. The method of making a power or communication cable jacket
according to claim 34, wherein said first component being
substantially free of any long chain branching, and said second
component being substantially free of any long chain branching.
48. The method of making a power or communication cable jacket
according to claim 47, wherein said high-density polyethylene
composition being substantially free of any long chain
branching.
49. The method of making a power or communication cable jacket
according to claim 34, wherein said high-density polyethylene
composition having a single ATREF temperature peak, wherein said
ATREF temperature peak having a temperature peak maximum between
90.degree. C. to 105.degree. C.; wherein said high-density
polyethylene composition having a calculated high density fraction
in the range of 20 percent to 50 percent, said calculated high
density fraction being defined as [(2)*(the weight ratio of the
high-density polyethylene that elutes in ATREF-DV at temperatures
grater than or equal to said temperature peak maximum)], wherein
said high-density polyethylene composition having a relative
minimum in the log of the relative viscosity average molecular
weight at about 90.degree. C. in ATRF-DV; wherein said high-density
polyethylene composition having a regression slop of the log of the
relative viscosity average molecular weight versus the ATREF-DV
viscosity versus temperature plot of less than about 0, said
elution temperature measured between 70.degree. C. to 90.degree.
C.
50. The method of making a power or communication cable jacket
according to claim 34, wherein said high-density polyethylene
composition having an ATREF high-density fraction in percent of
equal or less than [(2750*density of the high-density polyethylene
composition)-2552.2]*[1(percent)/(g/cm.sup.3)], where density is
measured in g/cm.sup.3.
51. The method of making a power or communication cable jacket
according to claim 34, wherein said high-density polyethylene
composition having a comonomer content in weight percent equal or
greater that [(-228.41*density of high-density polyethylene
composition)+219.36)]*[1(weight percent)/(g/cm.sup.3)], where
density is measured in g/cm.sup.3.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application claiming
priority from the U.S. Provisional Patent Application Ser. No.
60/796,809, filed on May 2, 2006 entitled "High-Density
Polyethylene Compositions and Method of Making the Same," the
teachings of which are herein as if reproduced in fill
hereinbelow.
FIELD OF INVENTION
[0002] The instant invention relates a high-density polyethylene
composition, method of producing the same, wire and cable jackets
made therefrom, and method of making such wire and cable
jackets.
BACKGROUND OF THE INVENTION
[0003] Cables, such as power or communication cables, typically
include an inner, which comprises a conducting element such as a
metal wire or a glass fiber, and one or more outer layers for
shielding and protecting purposes. The outermost layer of these
layers having mainly protective purpose is usually referred to as
the outer sheath or outer jacket.
[0004] The use of polymeric materials, such as polyolefins, to
manufacture outermost protective layers is generally known. In
particular, it is well known to produce outermost protective layers
from polyethylenes.
[0005] In general, the polymeric material used to manufacture cable
jackets should possess good processability, such as good extrusion
properties at broad processing temperature ranges. Furthermore,
such cable jackets should generally possess good mechanical
properties, such as good environmental stress crack resistance
(ESCR), high mechanical strength, high surface finish, and low
shrinkage.
[0006] Despite the research efforts in developing and improving
cable jackets, there is still a need for a polymeric composition
with improved processability and cable jackets made therefrom
having improved mechanical properties, such as improved
environmental stress crack resistance (ESCR), high mechanical
strength, high surface finish, and low shrinkage. The inventive
high-density polyethylene composition provides improved surface
smoothness, shrink-back and extrusion processing characteristics
without loss of other critical wire coating performance properties,
for example ESCR.
SUMMARY OF THE INVENTION
[0007] The instant invention is a high-density polyethylene
composition, method of producing the same, wire and cable jackets
made therefrom, and method of making such wire and cable jackets.
The high-density polyethylene composition of the instant invention
includes a first component, and a second component. The first
component is a high molecular weight ethylene alpha-olefin
copolymer having a density in the range of 0.915 to 0.940
g/cm.sup.3, and a melt index (I.sub.21.6) in the range of 0.5 to 10
g/10 minutes. The second component is a low molecular weight
ethylene polymer having a density in the range of 0.965 to 0.980
g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes. The high-density polyethylene composition has a melt
index (I.sub.2) of at least 1, a density in the range of 0.940 to
0.960 g/cm.sup.3, and g' of equal or greater than 1. The method of
producing a high-density polyethylene composition includes the
following steps: (1) introducing ethylene, and one or more
alpha-olefin comonomers into a first reactor; (2) (co)polymerizing
the ethylene in the presence of one or more alpha-olefin comonomers
in the first reactor thereby producing a first component, wherein
the first component being a high molecular weight ethylene
alpha-olefin copolymer having a density in the range of 0.915 to
0.940 g/cm.sup.3, and a melt index (I.sub.21.6) in the range of 0.5
to 10 g/10 minutes; (3) introducing the first component and
additional ethylene into a second reactor; (4) polymerizing the
additional ethylene in the second reactor thereby producing a
second component, wherein the second component being a low
molecular weight ethylene polymer having a density in the range of
0.965 to 0.980 g/cm.sup.3, and a melt index (I.sub.2) in the range
of 50 to 1500 g/110 minutes; and (5) thereby producing the
high-density polyethylene composition, wherein the high-density
polyethylene composition having a melt index (I.sub.2) of at least
1, a density in the range of 0.940 to 0.960 g/cm.sup.3, and g' of
equal or greater than 1. The wire and cable jackets according to
instant invention comprise the above-described inventive
high-density polyethylene composition, and such wire and cable
jackets may be made via extrusion process.
[0008] In one embodiment, the instant invention provides a
high-density polyethylene composition comprising a high molecular
weight polyethylene alpha-olefin copolymer having a density in the
range of 0.915 to 0.940 g/cm.sup.3, and a melt index (I.sub.21.6)
in the range of 0.5 to 10 g/10 minutes, and a low molecular weight
ethylene polymer having a density in the range of 0.965 to 0.980
g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes, wherein the inventive high-density polyethylene
composition having a melt index (I.sub.2) of at least 1 g/10
minutes, a density in the range of 0.940 to 0.960 g/cm.sup.3, and
g' of equal or greater than 1.
[0009] In an alternative embodiment, the instant invention further
provides a method for producing a high-density polyethylene
composition comprising the steps of: (1) introducing ethylene, and
one or more alpha-olefin comonomers into a first reactor; (2)
(co)polymerizing the ethylene in the presence of one or more
alpha-olefin comonomers in the first reactor thereby producing a
high molecular weight ethylene alpha-olefin copolymer having a
density in the range of 0.915 to 0.940 g/cm.sup.3, and a melt index
(I.sub.21) in the range of 0.5 to 10 g/10 minutes; (3) introducing
the high molecular weight ethylene alpha-olefin copolymer and
additional ethylene into a second reactor; (4) polymerizing the
additional ethylene in the second reactor thereby producing a low
molecular weight ethylene polymer having a density in the range of
0.965 to 0.980 g/cm.sup.3, and a melt index (I.sub.2) in the range
of 50 to 1500 g/10 minutes; and (5) thereby producing the
high-density polyethylene composition, wherein the high-density
polyethylene composition having a melt index (I.sub.2) of at least
1, a density in the range of 0.940 to 0.960 g/cm.sup.3, and g' of
equal or greater than 1.
[0010] In another alternative embodiment, the instant invention
provides wire and cable jackets comprising a high-density
polyethylene composition, wherein the high-density polyethylene
composition comprising a high molecular weight polyethylene
alpha-olefin copolymer having a density in the range of 0.915 to
0.940 g/cm.sup.3, and a melt index (I.sub.21.6) in the range of 0.5
to 10 g/10 minutes, and a low molecular weight ethylene polymer
having a density in the range of 0.965 to 0.980 g/cm.sup.3, and a
melt index (I.sub.2) in the range of 50 to 1500 g/10 minutes,
wherein the inventive high-density polyethylene composition having
a melt index (I.sub.2) of at least 1 g/10 minutes, a density in the
range of 0.940 to 0.960 g/cm.sup.3, and g' of equal or greater than
1.
[0011] In another alternative embodiment, the instant invention
provides a method of making wire and cable jackets comprising the
steps of: (1) providing a high-density polyethylene composition
comprising a high molecular weight ethylene alpha-olefin copolymer
having a density in the range of 0.915 to 0.940 g/cm.sup.3, and a
melt index (I.sub.21.6) in the range of 0.5 to 10 g/10 minutes; and
a low molecular weight ethylene polymer having a density in the
range of 0.965 to 0.980 g/cm.sup.3, and a melt index (I.sub.2) in
the range of 50 to 1500 g/10 minutes; wherein the high-density
polyethylene composition having a melt index (I.sub.2) of at least
1 g/10 minutes, a density in the range of 0.940 to 0.960
g/cm.sup.3, and g' of equal or greater than 1; (2) extruding said
high-density polyethylene composition over a power or communication
cable, and (3) thereby forming the power or communication cable
jacket.
[0012] In an alternative embodiment, the instant invention provides
a method for producing a high-density polyethylene composition,
method of producing the same, wire and cable jackets made
therefrom, and method of making such wire and cable jackets, in
accordance with any of the preceding embodiments except that the
high density polyethylene having a density in the range of 0.950 to
0.96 g/cm.sup.3.
[0013] In an alternative embodiment, the instant invention provides
a high-density polyethylene composition, method of producing the
same, wire and cable jackets made therefrom, and method of making
such wire and cable jackets, in accordance with any of the
preceding embodiments, except that the high molecular weight
polyethylene alpha-olefin copolymer having a density in the range
of 0.920 to 0.940 g/cm.sup.3.
[0014] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high molecular
weight polyethylene alpha-olefin copolymer having a density in the
range of 0.921 to 0.936 g/cm.sup.3.
[0015] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high molecular
weight polyethylene alpha-olefin copolymer having a melt index
(I.sub.21.6) in the range of 1 to 7 g/10 minutes.
[0016] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high molecular
weight polyethylene alpha-olefin copolymer having a melt index
(I.sub.21.6) in the range of 1.3 to 5 g/1 minutes.
[0017] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the low molecular
weight ethylene polymer having a density in the range of 0.970 to
0.975 g/cm.sup.3.
[0018] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the low molecular
weight ethylene polymer having a melt index (I.sub.2) in the range
of 100 to 1500 g/10 minutes.
[0019] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the low molecular
weight ethylene polymer having a melt index (I.sub.2) in the range
of 200 to 1500 g/10 minutes.
[0020] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high-density
polyethylene composition having a melt index (I.sub.2) in the range
of 1 to 2 g/10 minutes; or in the alternative, having a melt index
(I.sub.2) of at least 2 g/10 minutes.
[0021] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high molecular
weight ethylene alpha-olefin copolymer having a molecular weight in
the range of 150,000 to 375,000.
[0022] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the low molecular
weight ethylene polymer having a molecular weight in the range of
12,000 to 40,000.
[0023] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high molecular
weight polyethylene alpha-olefin copolymer having a density in the
range of 0.921 to 0.936 g/cm.sup.3, and a melt index (I.sub.21.6)
in the range of 1.3 to 5 g/10 minutes, and the low molecular weight
ethylene polymer having a density in the range of 0.970 to 0.975
g/cm.sup.3, and a melt index (I.sub.2) in the range of 200 to 1500
g/10 minutes.
[0024] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that both the high
molecular weight polyethylene alpha-olefin copolymer and the low
molecular weight ethylene polymer being substantially free of any
long chain branching.
[0025] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high-density
polyethylene composition being substantially free of any long chain
branching.
[0026] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high-density
polyethylene composition having a single ATREF temperature peak,
wherein the ATREF temperature peak having a temperature peak
maximum between 90.degree. C. to 105.degree. C.; and wherein the
high-density polyethylene composition having a calculated high
density fraction in the range of 20 percent to 50 percent, said
calculated high density fraction being defined as [(2).times.(the
weight ratio of the high-density polyethylene that elutes in
ATREF-DV at temperatures greater than or equal to the temperature
peak maximum)]; and wherein the high-density polyethylene
composition having a relative minimum in the log of the relative
viscosity average molecular weight at about 90.degree. C. in
ATRF-DV; and wherein the high-density polyethylene composition
having a regression slope of the log of the relative viscosity
average molecular weight versus the ATREF-DV viscosity v.
temperature plot of less than about 0, where the elution
temperature measured between 70.degree. C. to 90.degree. C.
[0027] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high-density
polyethylene composition having a comonomer content in weight
percent equal or greater that [(-228.41*density of high-density
polyethylene composition)+219.36)]*[1(weight
percent)/(g/cm.sup.3)], where density is measured in
g/cm.sup.3.
[0028] In another alternative embodiment, the instant invention
provides a high-density polyethylene composition, method of
producing the same, wire and cable jackets made therefrom, and
method of making such wire and cable jackets, in accordance with
any of the preceding embodiments, except that the high-density
polyethylene composition having an ATREF high-density fraction in
percent of equal or less than [(2750*density of the high-density
polyethylene composition)-2552.2]*[1(percent)/(g/cm.sup.3)], where
density is measured in g/cm.sup.3.
[0029] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that the high-density polyethylene composition
being extruded over a power or communication cable at a rate of at
least 200 ft/minute.
[0030] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having an average smoothness of
equal or less than 18 micro-inches.
[0031] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having an average surface
smoothness of equal or less than 15 micro-inches.
[0032] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having shrink on-wire after at
least 24 hours of equal or less than 1.3 percent.
[0033] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having shrink back off-wire after
at least 24 hours of equal or less than 3.39 percent.
[0034] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that the composition being extruded over a
power or communication cable at a rate of at least 300
ft/minute.
[0035] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having an average smoothness of
equal or less than 18 micro-inches.
[0036] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having an average surface
smoothness of equal or less than 15 micro-inches.
[0037] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having shrink on-wire after at
least 24 hours of equal or less than 1.3 percent.
[0038] In another alternative embodiment, the instant invention
provides wire and cable jackets and a method of making such wire
and cable jackets, in accordance with any of the preceding
embodiments, except that jacket having shrink back off-wire after
at least 24 hours of equal or less than 3.39 percent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] For the purpose of illustrating the instant invention, there
is shown in the drawings a form that is presently preferred; it
being understood, however, that this invention is not limited to
the precise arrangements and instrumentalities shown.
[0040] FIG. 1 is a graph illustrating the relationship between the
comonomer content and the density of the high-density polyethylene
composition of the instant invention;
[0041] FIG. 2 is a graph illustrating the relationship between high
density fraction measured via analytical temperature raising
elution fractionation analysis (ATREF) and density of the inventive
high-density polyethylene composition;
[0042] FIG. 3 is a graph illustrating the relationship between the
calculated high density fraction measured via analytical
temperature raising elution fractionation analysis (ATREF) and the
density of the high molecular weight polyethylene component of the
inventive high-density polyethylene composition; and
[0043] FIG. 4 illustrates how the calculated ATREF high-density
fraction of the high molecular weight polyethylene component of the
inventive Example 1 was determined.
DETAILED DESCRIPTION OF THE INVENTION
[0044] The high-density polyethylene composition of the instant
invention includes a first component, and a second component. The
first component is preferably a high molecular weight ethylene
alpha-olefin copolymer having a density in the range of 0.915 to
0.940 g/cm.sup.3, and a melt index (I.sub.21) of 0.5 to 10 g/10
minutes. The second component is preferably a low molecular weight
ethylene polymer having a density in the range of 0.965 to 0.980
g/cm.sup.3, and a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes. The high-density polyethylene composition has a melt
index (I.sub.2) of at least 1 g/10 minutes, a density in the range
of 0.950 to 0.960 g/cm.sup.3, and g' of equal or greater than 1.
The high-density polyethylene composition may further include
additional components, additives, or adjuvants. The high-density
polyethylene composition is a bimodal polymer, or in the
alternative, the high-density polyethylene is a multimodal
polymer.
[0045] The term "bimodal," as used herein, means that the molecular
weight distribution (MWD) in a Gel Permeation Chromatography (GPC)
curve exhibits two component polymers, for example, two peaks or
wherein one component polymer may even exist as a hump, shoulder,
or tail relative to the MWD of the other component polymer; or in
the alternative, for example, wherein the two components may have
only one single peak with no bumps, shoulders, or tails.
[0046] The term "multimodal" as used herein means that the MWD in a
GPC curve exhibits more than two component polymers, for example,
three or more peaks or wherein one component polymer may even exist
as a hump, shoulder, or tail, relative to the MWD of the other
component polymers; or in the alternative, wherein three or more
components may have only one single pick with no bumps, shoulders,
or tails.
[0047] The term "polymer" is used herein to indicate a homopolymer,
an interpolymer (or copolymer), or a terpolymer. The term
"polymer," as used herein, includes interpolymers, such as, for
example, those made by the copolymerization of ethylene with one or
more C.sub.3-C.sub.20 alpha-olefin(s).
[0048] The term "interpolymer," as used herein, refers to polymers
prepared by the polymerization of at least two different types of
monomers. The generic term interpolymer thus includes copolymers,
usually employed to refer to polymers prepared from two different
types of monomers, and polymers prepared from more than two
different types of monomers.
[0049] The term (co)polymerization, as used herein, refers to
polymerization of ethylene in the presence of one or more
alpha-olefin comonomers.
[0050] The first component is a polymer; for example, a polyolefin.
The first component is preferably be an ethylene polymer; for
example, first component is preferably a high molecular weight
ethylene alpha-olefin copolymer. The first component is
substantially free of any long chain branching. Substantially free
of any long chain branching, as used herein, refers to an ethylene
polymer preferably substituted with less than about 0.1 long chain
branch per 1000 total carbons, and more preferably, less than about
0.01 long chain branch per 1000 total carbons. The presence of long
chain branches is typically determined according to the methods
known in the art, such as gel permeation chromatography coupled
with low angle laser light scattering detector (GPC-LALLS) and gel
permeation chromatography coupled with a differential viscometer
detector (GPC-DV). The first component has a density in the range
of 0.915 to 0.940 g/cm.sup.3. All individual values and subranges
from 0.915 to 0.940 g/cm.sup.3 are included herein and disclosed
herein; for example, the first component has a density in the range
of 0.920 to 0.940 g/cm.sup.3, or in the alternative, the first
component has a density in the range of 0.921 to 0.936 g/cm.sup.3.
The first component has a melt index (I.sub.21.6) in the range of
0.5 to 10 g/10 minutes. All individual values and subranges from
0.5 to 10 g/10 minutes are included herein and disclosed herein;
for example, the first component has a melt index (I.sub.21.6) in
the range of 1 to 7 g/10 minutes, or in the alternative, the first
component has a melt index (I.sub.21.6) in the range of 1.3 to 5
g/10 minutes. The first component has molecular weight in the range
of 150,000 to 375,000. All individual values and subranges from
150,000 to 375,000 are included herein and disclosed herein; for
example, the first component has a molecular weight in the range of
175,000 to 375,000; or in the alternative, the first component has
a molecular weight in the range of 200,000 to 375,000. The first
component may comprise any amount of one or more alpha-olefin
copolymers; for example, the first component comprises about less
than 10 percent by weight of one or more alpha-olefin comonomers,
based on the weight of the first component. All individual values
and subranges less than 10 weight percent are included herein and
disclosed herein. The first component may comprise any amount of
ethylene; for example, the first component comprises at least about
90 percent by weight of ethylene, based on the weight of the first
component. All individual values and subranges above 90 weight
percent are included herein and disclosed herein; for example, the
first component comprises at least 95 percent by weight of
ethylene, based on the weight of the first component.
[0051] The alpha-olefin comonomers typically have no more than 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 alpha-olefin comonomers are preferably selected from the group
consisting of propylene, 1-butene, 1-hexene, and 1-octene, and more
preferably from the group consisting of 1-hexene and 1-octene.
[0052] The second component is a polymer; for example, a
polyolefin. The second component is preferably an ethylene polymer;
for example, second component is preferably a low molecular weight
ethylene homopolymer. The ethylene homopolymer may contain trace
amounts of contaminate comonomers, for example alpha-olefin
comonomers. The term ethylene homopolymer, as used herein, refers
to an ethylene polymer containing at least 99 percent by weight of
ethylene units. The second component is preferably substantially
free of any long chain branching. Substantially free of any long
chain branching, as used herein, refers to an ethylene polymer
preferably substituted with less than about 0.1 long chain branch
per 1000 total carbons, and more preferably, less than about 0.01
long chain branch per 1000 total carbons. The presence of long
chain branches is typically determined according to the methods
known in the art, as mentioned above. The second component has a
density in the range of 0.965 to 0.980 g/cm.sup.3. All individual
values and subranges from 0.965 to 0.980 g/cm.sup.3 are included
herein and disclosed herein; for example, the second component has
a density in the range of 0.970 to 0.975 g/cm.sup.3. The second
component has a melt index (I.sub.2) in the range of 50 to 1500
g/10 minutes. All individual values and subranges from 50 to 1500
g/10 minutes are included herein and disclosed herein; for example,
the second component has a melt index (I.sub.2) in the range of 200
to 1500 g/10 minutes; or in the alternative, the second component
has a melt index (I.sub.2) in the range of 500 to 1500 g/10
minutes. The second component has a molecular weight in the range
of 12,000 to 40,000. All individual values and subranges from
12,000 to 40,000 are included herein and disclosed herein; for
example, the second component has a molecular weight in the range
of 15,000 to 40,000; or in the alternative, the second component
has a molecular weight in the range of 20,000 to 40,000. The second
component comprises less than 1.00 percent by weight of one or more
alpha-olefin copolymers, based on the weight of the second
component. All individual values and subranges from less than 1.00
weight percent are included herein and disclosed herein; for
example, the second component may comprise 0.0001 to 1.00 percent
by weight of one or more alpha-olefin copolymers; the second
component may comprise 0.001 to 1.00 percent by weight of one or
more alpha-olefin copolymers. The second component comprises at
least about 99 percent by weight of ethylene, based on the weight
of the second component. All individual values and subranges from
99 to 100 weight percent are included herein and disclosed herein;
for example, the second component comprises 99.5 to 100 percent by
weight of ethylene, based on the weight of the second
component.
[0053] The high-density polyethylene composition has a density in
the range of 0.940 to 0.960 g/cm.sup.3. All individual values and
subranges from 0.940 to 0.960 g/cm.sup.3 are included herein and
disclosed herein; for example, the high-density polyethylene
composition has a density in the range of 0.950 to 0.960
g/cm.sup.3. The high-density polyethylene composition has a melt
index (I.sub.2) of at least 1 g/10 minutes. All individual values
and subranges equal or greater than 1 g/10 minutes are included
herein and disclosed herein; for example, the high-density
polyethylene composition has a melt index (I.sub.2) in the range of
1 to 2 g/10 minutes; or in the alternative, the high-density
polyethylene composition has a melt index (I.sub.2) of at least 2
g/10 minutes. The high-density polyethylene composition is
substantially free of any long chain branching. Substantially free
of any long chain branching, as used herein, refers to a
polyethylene composition preferably substituted with less than
about 0.1 long chain branch per 1000 total carbons, and more
preferably, less than about 0.01 long chain branch per 1000 total
carbons. The presence of long chain branches is typically
determined according to the methods known in the art, as mentioned
above. The high-density polyethylene composition has a molecular
weight distribution in the range of 6 to 25. All individual values
and subranges from 6 to 25 are included herein and disclosed
herein; for example, the high-density polyethylene composition has
a molecular weight distribution in the range of 7 to 20; or in the
alternative, the high-density polyethylene composition has a
molecular weight distribution in the range of 7 to 17. The term
molecular weight distribution or "MWD," as used herein, refers to
the ratio of weight average molecular weight (M.sub.w) to number
average molecular weight (M.sub.n), that is (M.sub.w/M.sub.n),
described in further details hereinbelow. The high-density
polyethylene composition has an environmental stress crack
resistance of at least 150 hours measured via ASTM D-1693,
Condition B, 10 percent Igepal, or preferably at least 200 hours
measured via ASTM D-1693, Condition B, 10% Igepal, or more
preferably, at least 250 hours measured via ASTM D-1693, Condition
B, 10 percent Igepal. In the alternative, the high-density
polyethylene composition has an environmental stress crack
resistance of at least 300 hours measured via ASTM D-1693,
Condition B, 100 percent Igepal, or preferably, at least 400 hours
measured via ASTM D-1693, Condition B, 100 percent Igepal, or more
preferably, at least 500 hours measured via ASTM D-1693, Condition
B, 100 percent Igepal. The high-density polyethylene composition
may comprise any amounts of first component, second component, or
combinations thereof. The high-density polyethylene composition
comprises 40 to 60 percent by weight of the first component, based
on the total weight of the first and second components. All
individual values and subranges from 40 to 60 weight percent are
included herein and disclosed herein; for example, the high-density
polyethylene composition comprises 42 to 55 percent by weight of
the first component, based on the total weight of first and second
components. The high-density polyethylene composition further
comprises 40 to 60 percent by weight of the second component, based
on the total weight of the first and second components. All
individual values and subranges from 40 to 60 weight percent are
included herein and disclosed herein; for example, the high-density
polyethylene composition further comprises 48 to 55 percent by
weight of the second component, based on the total weight of the
first and second components. Preferably, the high-density
polyethylene composition has a single ATREF temperature peak,
wherein the ATREF temperature peak having a temperature peak
maximum between 90.degree. C. to 105.degree. C., as described
hereinbelow in further details. The high-density polyethylene
composition further has a calculated high-density fraction in the
range of 20 percent to 50 percent. All individual values and
subranges from 20 percent to 50 percent are included herein and
disclosed herein. The calculated high-density fraction, as used
herein, refers to [(2).times.(the weight ratio of the high-density
polyethylene that elutes in ATREF-DV at temperatures greater than
or equal to the temperature peak maximum]. Additionally, the
high-density polyethylene composition has a relative minimum in the
log of the relative viscosity average molecular weight at about
90.degree. C. in ATRF-DV, and a regression slope of the log of the
relative viscosity average molecular weight versus the ATREF-DV
viscosity versus temperature plot of less than about 0, where the
elution temperature is measured between 70.degree. C. to 90.degree.
C.
[0054] The ATREF high-density fraction (percent) of the
polyethylene composition is calculated by integrating the area
under the curve from 86.degree. C. and higher as long as there is
no relative minimum in the curve. None of the inventive or
comparative samples measured and reported in the tables had a
relative minimum in the curve from 86.degree. C. and higher
temperatures.
[0055] The high-density polyethylene composition has a g' average
of equal or greater than 1 measured by triple detector gel
permeation chromatography (GPC), described in further details
herein below. g' is expressed as the ratio of intrinsic viscosity
of the instant high-density polyethylene composition to the
intrinsic viscosity of a linear polymer reference. If the g' is
equal or greater than 1 then the sample being analyzed is
considered linear, and if g' is less than 1, it is, then, by
definition a branched polymer as compared to a linear polymer.
However, current testing methods may be subject to errors in their
precision and accuracy; thus, proper steps must be taken into
account for such precision errors. Therefore, small deviations, for
example values of less than or equal to 0.012, from unity, that is
0.988 to 1.012, would still be defined as linear polymers. In the
alternative, small deviation, for example values of less than or
equal to 0.025, from unity, that is 0.975 to 1.025, would still be
defined as linear polymers.
[0056] Referring to FIG. 1, the high-density polyethylene
composition has an ATREF high-density fraction in percent of equal
or less than [(2750*density of the high-density polyethylene
composition)-2552.2]*[1(percent)/(g/cm.sup.3)], where density is
measured in g/cm.sup.3.
[0057] Referring to FIG. 2, the high-density polyethylene
composition has a comonomer content in weight percent equal or
greater that [(-228.41*density of high-density polyethylene
composition)+219.36)]*[1(weight percent)/(g/cm.sup.3)], where
density is measured in g/cm.sup.3.
[0058] Referring to FIG. 3, the calculated high density fraction in
percent is equal to [1107.4*(density of the high molecular weight
polyethylene component)-992.56]*[1(percent/(g/cm.sup.3).
[0059] Referring to FIG. 4, FIG. 4 illustrates the relationship
between the elution temperatures in .degree. C. and viscosity
average in Log[M.sub.V(g/Mole)].
[0060] The high-density polyethylene composition may further
include additional components such as other polymers, adjuvants,
and/or additives. Such adjuvants or additives include, but are not
limited to, antistatic agents, color enhancers, dyes, lubricants,
fillers, pigments, primary antioxidants, secondary antioxidants,
processing aids, UV stabilizers, nucleators, viscosity control
agents, tackifiers, anti-blocking agents, surfactants, extender
oils, metal deactivators, flame retardants, smoke suppressants, and
combinations thereof. The high-density polyethylene composition
compromises about less than 10 percent by the combined weight of
one or more additives, based on the weight of the high-density
polyethylene composition. All individual values and subranges from
about less than 10 weight percent are included herein and disclosed
herein; for example, the high-density polyethylene composition
comprises about less than 5 percent by the combined weight of one
or more additives, based on the weight of the high-density
polyethylene composition; or in the alternative, the high-density
polyethylene composition comprises about less than 1 percent by the
combined weight of one or more additives, based on the weight of
the high-density polyethylene composition; or in another
alternative, the high-density polyethylene composition may
compromise about less than 0.5 percent by the combined weight of
one or more additives, based on the weight of the high-density
polyethylene composition. Antioxidants, such as Irgafos.RTM. 168
and Irganox.RTM. 1010, are commonly used to protect the polymer
from thermal and/or oxidative degradation. Irganox.RTM. 1010 is
tetrakis (methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate),
which is commercially available from Ciba Geigy Inc. Irgafos.RTM.
168 is tris (2,4 di-tert-butylphenyl) phosphite, which is
commercially available from Ciba Geigy Inc.
[0061] The inventive high-density polyethylene composition may
further be blended with other polymers. Such other polymers are
generally known to a person of ordinary skill in the art. Blends
comprising the inventive high-density polyethylene composition is
formed via any conventional methods. For example, the selected
polymers are melt blended via a single or twin screw extruder, or a
mixer, for example a Banbury mixer, a Haake mixer, a Barbender
internal mixer.
[0062] In general, blends containing the inventive high-density
polyethylene composition comprises at least 40 percent by weight of
the inventive high-density polyethylene composition, based on the
total weight of the blend. All individual values and subranges in
the range of at least 40 weight percent are included herein and
disclosed herein; for example, the blend comprises at least 50
percent by weight of the inventive high-density polyethylene
composition, based on the total weight of the blend; or in the
alternative, the blend comprises at least 60 percent by weight of
the inventive high-density polyethylene composition, based on the
total weight of the blend; or in the alternative, the blend
comprises at least 70 percent by weight of the inventive
high-density polyethylene composition, based on the total weight of
the blend; or in the alternative, the blend comprises at least 80
percent by weight of the inventive high-density polyethylene
composition, based on the total weight of the blend; or in the
alternative, the blend comprises at least 90 percent by weight of
the inventive high-density polyethylene composition, based on the
total weight of the blend; or in the alternative, the blend
comprises at least 95 percent by weight of the inventive
high-density polyethylene composition, based on the total weight of
the blend; or in the alternative, the blend comprises at least
99.99 percent by weight of the inventive high-density polyethylene
composition, based on the total weight of the blend.
[0063] Different polymerization reactions and catalyst systems may
be employed to produce the inventive high-density polyethylene
composition. Typical transition metal catalyst systems used to
prepare the high-density polyethylene composition are
magnesium/titanium based catalyst systems, exemplified by the
catalyst system described in U.S. Pat. No. 4,302,565; vanadium
based catalyst systems, such as those described in U.S. Pat. No.
4,508,842; U.S. Pat. No. 5,332,793; U.S. Pat. No. 5,342,907; and
U.S. Pat. No. 5,410,003; and a metallocene catalyst system, such as
those described in U.S. Pat. No. 4,937,299; U.S. Pat. No.
5,317,036; and U.S. Pat. No. 5,527,752. Catalyst systems that use
molybdenum oxides on silica-alumina supports are also useful.
Preferred catalyst systems for preparing the components for the
inventive high-density polyethylene composition are Ziegler-Natta
catalyst systems and metallocene catalyst systems.
[0064] In some embodiments, preferred catalysts used in the process
to make the high-density polyethylene compositions are of the
magnesium/titanium type. In particular, for the gas phase
polymerizations, the catalyst is made from a precursor comprising
magnesium and titanium chlorides in an electron donor solvent. This
solution is often either deposited on a porous catalyst support, or
a filler is added, which, on subsequent spray drying, provides
additional mechanical strength to the particles. The solid
particles from either support methods are often slurried in a
diluent producing a high viscosity mixture, which is then used as
catalyst precursor. Exemplary catalyst types are described in U.S.
Pat. No. 6,187,866 and U.S. Pat. No. 5,290,745, the entire contents
of both of which are herein. Precipitated/crystallized catalyst
systems, such as those described in U.S. Pat. No. 6,511,935 and
U.S. Pat. No. 6,248,831, the entire contents of both of which are
herein, may also be used. Such catalysts may further be modified
with one precursor activator. Such further modifications are
described in US patent publication No.: US2006/0287445 A1.
[0065] Preferably the catalyst precursor has the formula
Mg.sub.dTi(OR).sub.eX.sub.f(ED).sub.g wherein R is an aliphatic or
aromatic hydrocarbon radical having 1 to 14 carbon atoms or COR'
wherein R' is a aliphatic or aromatic hydrocarbon radical having 1
to 14 carbon atoms; each OR group is the same or different; X is
independently chlorine, bromine or iodine; ED is an electron donor;
d is 0.5 to 56; e is 0, 1, or 2; f is 2 to 116; and g is >2 and
up to 1.5*d+3. It is prepared from a titanium compound, a magnesium
compound, and an electron donor.
[0066] The electron donor is an organic Lewis base, liquid at
temperatures in the range of 0.degree. C. to 200.degree. C., in
which the magnesium and titanium compounds are soluble. The
electron donor compounds are sometimes also referred to as Lewis
bases. The electron donor can be an alkyl ester of an aliphatic or
aromatic carboxylic acid, an aliphatic ketone, an aliphatic amine,
an aliphatic alcohol, an alkyl or cycloalkyl ether, or mixtures
thereof, each electron donor having 2 to 20 carbon atoms. Among
these electron donors, the preferred are alkyl and cycloalkyl
ethers having 2 to 20 carbon atoms; dialkyl, diaryl, and alkylaryl
ketones having 3 to 20 carbon atoms; and alkyl, alkoxy, and
alkylalkoxy esters of alkyl and aryl carboxylic acids having 2 to
20 carbon atoms. The most preferred electron donor is
tetrahydrofuran. Other examples of suitable electron donors are
methyl formate, ethyl acetate, butyl acetate, ethyl ether, dioxane,
di-n-propyl ether, dibutyl ether, ethanol, 1-butanol, ethyl
formate, methyl acetate, ethyl anisate, ethylene carbonate,
tetrahydropyran, and ethyl propionate.
[0067] While a large excess of electron donor may be used initially
to provide the reaction product of titanium compound and electron
donor, the final catalyst precursor contains approximately 1 to
approximately 20 moles of electron donor per mole of titanium
compound and preferably approximately 1 to approximately 10 moles
of electron donor per mole of titanium compound.
[0068] Since the catalyst will act as a template for the growth of
the polymer, it is essential that the catalyst precursor be
converted into a solid. It is also essential that the resultant
solid has the appropriate particle size and shape to produce
polymer particles with relatively narrow size distribution, low
amounts of fines and good fluidization characteristics. Although
this solution of Lewis Base, magnesium and titanium compounds may
be impregnated into a porous support and dried to form a solid
catalyst; it is preferred that the solution be converted into a
solid catalyst via spray drying. Each of these methods thus forms a
"supported catalyst precursor."
[0069] The spray dried catalyst product is then preferentially
placed into a mineral oil slurry. The viscosity of the hydrocarbon
slurry diluent is sufficiently low, so that the slurry can be
conveniently pumped through the pre-activation apparatus, and
eventually into the polymerization reactor. The catalyst is fed
using a slurry catalyst feeder. A progressive cavity pump, such as
a Moyno pump is typically used in commercial reaction systems,
while a dual piston syringe pump is typically used in pilot scale
reaction systems, where the catalyst flows are less than, or equal
to, 10 cm.sup.3/hour (2.78.times.10.sup.-9 m.sup.3/s) of
slurry.
[0070] A cocatalyst, or activator, is also fed to the reactor to
effect the polymerization. Complete activation by additional
cocatalyst is required to achieve full activity. The complete
activation normally occurs in the polymerization reactor, although
the techniques taught in EP 1,200,483 may also be used.
[0071] The cocatalysts, which are reducing agents, conventionally
used, are comprised of aluminum compounds, but compounds of
lithium, sodium and potassium, alkaline earth metals, as well as
compounds of other earth metals than aluminum are possible. The
compounds are usually hydrides, organometal or halide compounds.
Butyl lithium and dibutyl magnesium are examples of useful
compounds of other than aluminum.
[0072] An activator compound, which is generally used with any of
the titanium based catalyst precursors, can have the formula
AlR.sub.aX.sub.bH.sub.c, wherein each X is independently chlorine,
bromine, iodine, or OR'; each R and R' is independently a saturated
aliphatic hydrocarbon radical having 1 to 14 carbon atoms; b is 0
to 1.5; c is 0 or 1; and a+b+c=3. Preferred activators include
alkylaluminum mono- and dichlorides, wherein each alkyl radical has
1 to 6 carbon atoms and the trialkylaluminums. Examples are
diethylaluminum chloride and tri-n-hexylaluminum. About 0.10 to 10
moles, and preferably 0.15 to 2.5 moles, of activator are used per
mole of electron donor. The molar ratio of activator to titanium is
in the range from 1:1 to 10:1, and is preferably in the range from
2:1 to 5:1.
[0073] The hydrocarbyl aluminum cocatalyst can be represented by
the formula R.sub.3Al or R.sub.2AlX, wherein each R is
independently alkyl, cycloalkyl, aryl, or hydrogen; at least one R
is hydrocarbyl; and two or three R radicals can be joined to form a
heterocyclic structure. Each R, which is a hydrocarbyl radical, can
have 1 to 20 carbon atoms, and preferably has 1 to 10 carbon atoms.
X is a halogen, preferably chlorine, bromine, or iodine. Examples
of hydrocarbyl aluminum compounds are as follows:
triisobutylaluminum, tri-n-hexylaluminum, di-isobutyl-aluminum
hydride, dihexylaluminum hydride, di-isobutylhexylaluminum,
isobutyl dihexylaluminum, trimethylaluminum, triethylaluminum,
tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum,
trioctylaluminum, tridecylaluminum, tridodecylaluminum,
tribenzylaluminum, triphenylaluminum, trinaphthylaluminum,
tritolylaluminum, dibutylaluminum chloride, diethylaluminum
chloride, and ethylaluminum sesquichloride. The cocatalyst
compounds can also serve as activators and modifiers.
[0074] Activators can be added to the precursor either before
and/or during polymerization. In one procedure, the precursor is
fully activated before polymerization. In another procedure, the
precursor is partially activated before polymerization, and
activation is completed in the reactor. Where a modifier is used
instead of an activator, the modifiers are usually dissolved in an
organic solvent such as isopentane and, where a support is used,
impregnated into the support following impregnation of the titanium
compound or complex, after which the supported catalyst precursor
is dried. Otherwise, the modifier solution is added by itself
directly to the reactor. Modifiers are similar in chemical
structure and function to the activators as are cocatalysts. For
variations, see for example, U.S. Pat. No. 5,106,926, incorporated
herein by reference in its entirety. The cocatalyst is preferably
added separately neat or as a solution in an inert solvent, such as
isopentane, to the polymerization reactor at the same time as the
flow of ethylene is initiated.
[0075] In those embodiments that use a support, the precursor is
supported on an inorganic oxide support such as silica, aluminum
phosphate, alumina, silica/alumina mixtures, silica that has been
modified with an organoaluminum compound such as triethyl aluminum,
and silica modified with diethyl zinc. In some embodiments silica
is a preferred support. A typical support is a solid, particulate,
porous material essentially inert to the polymerization. It is used
as a dry powder having an average particle size of 10 to 250 .mu.m
and preferably 30 to 100 .mu.m; a surface area of at least 200
m.sup.2/g and preferably at least 250 m.sup.2/g; and a pore size of
at least 100.times.10.sup.-10 m and preferably at least
200.times.10.sup.-10 m. Generally, the amount of support used is
that which will provide 0.1 to 1.0 millimole of titanium per gram
of support and preferably 0.4 to 0.9 millimole of titanium per gram
of support. Impregnation of the above mentioned catalyst precursor
into a silica support can be accomplished by mixing the precursor
and silica gel in the electron donor solvent or other solvent
followed by solvent removal under reduced pressure. When a support
is not desired, the catalyst precursor can be used in liquid
form.
[0076] In another embodiment, metallocene catalysts, single-site
catalysts and constrained geometry catalysts may be used in the
practice of the invention. Generally, metallocene catalyst
compounds include half and full sandwich compounds having one or
more .pi.-bonded ligands including cyclopentadienyl-type structures
or other similar functioning structure such as pentadiene,
cyclooctatetraendiyl and imides. Typical compounds are generally
described as containing one or more ligands capable of .pi.-bonding
to a transition metal atom, usually, cyclopentadienyl derived
ligands or moieties, in combination with a transition metal
selected from Group 3 to 8, preferably 4, 5 or 6 or from the
lanthanide and actinide series of the Periodic Table of
Elements.
[0077] Exemplary of metallocene-type catalyst compounds are
described in, for example, U.S. Pat. Nos. 4,530,914; 4,871,705;
4,937,299; 5,017,714; 5,055,438; 5,096,867; 5,120,867; 5,124,418;
5,198,401; 5,210,352; 5,229,478; 5,264,405; 5,278,264; 5,278,119;
5,304,614; 5,324,800; 5,347,025; 5,350,723; 5,384,299; 5,391,790;
5,391,789; 5,399,636; 5,408,017; 5,491,207; 5,455,366; 5,534,473;
5,539,124; 5,554,775; 5,621,126; 5,684,098; 5,693,730; 5,698,634;
5,710,297; 5,712,354; 5,714,427; 5,714,555; 5,728,641; 5,728,839;
5,753,577; 5,767,209; 5,770,753 and 5,770,664; European
publications: EP-A-0 591 756; EP-A-0 520 732; EP-A-0 420 436;
EP-A-0 485 822; EP-A-0 485 823; EP-A-0 743 324; EP-A-0 518 092; and
PCT publications: WO 91/04257; WO 92/00333; WO 93/08221; WO
93/08199; WO 94/01471; WO 96/20233; WO 97/15582; WO 97/19959; WO
97/46567; WO 98/01455; WO 98/06759 and WO 98/011144. All of these
references are incorporated herein, in their entirety, by
reference.
[0078] Suitable catalysts for use herein, preferably include
constrained geometry catalysts as disclosed in U.S. Pat. Nos.
5,272,236 and 5,278,272, which are both incorporated, in their
entirety, by reference.
[0079] The monocyclopentadienyl transition metal olefin
polymerization catalysts taught in U.S. Pat. No. 5,026,798, the
teachings of which are incorporated herein by reference, are also
suitable as catalysts of the invention.
[0080] The foregoing catalysts may be further described as
comprising a metal coordination complex comprising a metal of
groups 3-10 or the Lanthanide series of the Periodic Table of the
Elements, and a delocalized .pi.-bonded moiety, substituted with a
constrain-inducing moiety. Such a complex has a constrained
geometry about the metal atom. The catalyst further comprises an
activating cocatalyst.
[0081] Any conventional ethylene homopolymerization or
(co)polymerization reactions may be employed to produce the
inventive high-density polyethylene composition. Such conventional
ethylene homopolymerization or (co)polymerization reactions
include, but are not limited to, gas phase polymerization, slurry
phase polymerization, liquid phase polymerization, and combinations
thereof using conventional reactors, for example gas phase
reactors, loop reactors, stirred tank reactors, and batch reactors
in series, or in series and parallel. The polymerization system of
the instant invention is a dual sequential polymerization system or
a multi-sequential polymerization system. Examples of dual
sequential polymerization system include, but are not limited to,
gas phase polymerization/gas phase polymerization; gas phase
polymerization/liquid phase polymerization; liquid phase
polymerization/gas phase polymerization; liquid phase
polymerization/liquid phase polymerization; slurry phase
polymerization/slurry phase polymerization; liquid phase
polymerization/slurry phase polymerization; slurry phase
polymerization/liquid phase polymerization; slurry phase
polymerization/gas phase polymerization; and gas phase
polymerization/slurry phase polymerization. The multi-sequential
polymerization systems includes at least three polymerization
reactions. The catalyst system, described above, may also be a
conventional catalyst system. The inventive high-density
polyethylene composition is preferably produced via a dual gas
phase polymerization process, for example gas phase
polymerization/gas phase polymerization; however, the instant
invention is not so limited, and any of the above combinations may
be employed.
[0082] In production, a dual sequential polymerization system
connected in series, as described above, may be used. The first
component, that is the high molecular weight ethylene polymer, can
be produced in the first stage of the dual sequential
polymerization system, and the second component, that is the low
molecular weight ethylene polymer, can be prepared in the second
stage of the dual sequential polymerization system. Alternatively,
the second component, that is the low molecular weight ethylene
polymer, can be made in the first stage of the dual sequential
polymerization system, and the first component, that is the high
molecular weight ethylene polymer, can be made in the second stage
of the dual sequential polymerization system.
[0083] For purposes of the present disclosure, the reactor, in
which the conditions are conducive to making the first component is
known as the first reactor. Alternatively, the reactor in which the
conditions are conducive to making the second component is known as
the second reactor.
[0084] In production, a catalyst system including a cocatalyst,
ethylene, one or more alpha-olefin comonomers, hydrogen, and
optionally inert gases and/or liquids, for example N.sub.2,
isopentane, and hexane, are continuously fed into a first reactor,
which is connected to a second reactor in series; the first
component/active catalyst mixture is then continuously transferred,
for example, in batches from the first reactor to the second
reactor. Ethylene, hydrogen, cocatalyst, and optionally inert gases
and/or liquids, for example N.sub.2, isopentane, hexane, are
continuously fed to the second reactor, and the final product, that
is the inventive high-density polyethylene composition, is
continuously removed, for example, in batches from the second
reactor. A preferred mode is to take batch quantities of first
component from the first reactor, and transfer these to the second
reactor using the differential pressure generated by a recycled gas
compression system. The inventive high-density polyethylene
composition is then transferred to a purge bin under inert
atmosphere conditions. Subsequently, the residual hydrocarbons are
removed, and moisture is introduced to reduce any residual aluminum
alkyls and any residual catalysts before the inventive high-density
polyethylene composition is exposed to oxygen. The inventive
high-density polyethylene composition is then transferred to an
extruder to be pelletized. Such pelletization techniques are
generally known. The inventive high-density polyethylene
composition may further be melt screened. Subsequent to the melting
process in the extruder, the molten composition is passed through
one or more active screens (positioned in series of more than one)
with each active screen having a micron retention size of from 2 to
400 (2 to 4.times.10.sup.-5 m), and preferably 2 to 300 (2 to
3.times.10.sup.-5 m), and most preferably 2 to 70 (2 to
7.times.10.sup.-6 m), at a mass flux of 5 to 100 lb/hr/in.sup.2
(1.0 to about 20 kg/s/m.sup.2). Such further melt screening is
disclosed in U.S. Pat. No. 6,485,662, which is incorporated herein
by reference to the extent that it discloses melt screening.
[0085] In an alternative production, a multi-sequential
polymerization system connected in series and parallel, as
described above, may be used. In one embodiment of the instant
invention, a catalyst system including a cocatalyst, ethylene, one
or more alpha-olefin comonomers, hydrogen, and optionally inert
gases and/or liquids, for example N.sub.2, isopentane, and hexane,
are continuously fed into a first reactor, which is connected to a
second reactor, wherein the second reactor is connected to a third
reactor in series; the first component/active catalyst mixture is
then continuously transferred, for example, in batches from the
first reactor to the second reactor, and then to the third reactor.
Ethylene, hydrogen, cocatalyst, and optionally inert gases and/or
liquids, for example N.sub.2, isopentane, and hexane, are
continuously fed to the second and third reactors, and the final
product, that is high-density polyethylene composition, is
continuously removed, for example, in batches from the third
reactor. A preferred mode is to take batch quantities of first
component from the first reactor, and transfer these to the second
reactor, and then take batches from the second reactor and transfer
these to the third reactor in series using the differential
pressure generated by a recycled gas compression system.
Alternatively, the first reactor may feed to both a second reactor
and a third reactor in parallel, and the product from first reactor
may be transferred to either second or third reactor. The
high-density polyethylene composition is then transferred to a
purge bin under inert atmosphere conditions. Subsequently, the
residual hydrocarbons are removed, and moisture may be introduced
to reduce any residual aluminum alkyls and any residual catalysts
before the polymer, that is the inventive high-density polyethylene
composition, is exposed to oxygen. The inventive high-density
polyethylene composition is then transferred to an extruder to be
pelletized. Such pelletization techniques are generally known. The
inventive high-density polyethylene composition may further be melt
screened. Subsequent to the melting process in the extruder, the
molten composition is passed through one or more active screens
(positioned in series of more than one) with each active screen
having a micron retention size of from 2 to 400 (2 to
4.times.10.sup.-5 m), and preferably 2 to 300 (2 to
3.times.10.sup.-5 m), and most preferably 2 to 70 (2 to
7.times.10.sup.-6 m), at a mass flux of 5 to 100 lb/hr/in.sup.2
(1.0 to about 20 kg/s/m.sup.2). Such further melt screening is
disclosed in U.S. Pat. No. 6,485,662, which is incorporated herein
by reference to the extent that it discloses melt screening.
[0086] In another alternative production, the inventive
high-density polyethylene composition may be produced from polymers
made in two independent reactors (each using the same or different
catalyst) with post reaction blending.
[0087] In application, the inventive high-density polyethylene
composition may be used to manufacture shaped articles. Such
articles may include, but are not limited to, power or
communication cable jackets, or power or communication cable
insulation products. Different methods may be employed to
manufacture articles such as power or communication cable jackets,
or power or communication cable insulation products. Suitable
conversion techniques include, but are not limited to, wire coating
via extrusion. Such techniques are generally well known.
[0088] In extrusion process, the high-density polyethylene
composition is applied on a conducting element, for example glass
fiber, copper wire, or cable core construction, via extrusion
process. The extruder is usually a conventional one using a
crosshead die, which provides the desired layer (wall or coating)
thickness. An example of an extruder, which can be used is the
single screw type modified with a crosshead die, cooling through
and continuous take-up equipment. A typical single screw type
extruder can be described as one having a hopper at its upstream
end and a die at its downstream end. The hopper feeds into the
barrel, which contains a screw. At the downstream end, between the
end of the screw and the die is a screen pack and a breaker plate.
The screw portion of the extruder is considered to be divided up
into three sections, the feed section, the compression section, and
the metering section, and multiple heating zones from the rear
heating zone to the front heating zone with the multiple sections
running from upstream to downstream. The length to diameter ratio
of the barrel is in the range of 16:1 to 30:1. Grooved barrel
extruders or twin screw extruders can also be employed in the wire
coating process. The jacketing extrusion can take place at
temperatures in the range of 160.degree. C. to about 260.degree.
C., and it is typically carried out at temperatures in the range of
180.degree. C. to 240.degree. C. The crosshead die distributes the
polymer melt in a flow channel such that the material exits with a
uniform velocity. The conducting elements, for example single
fiber, wire or core passes through the center of the crosshead, and
as it exits a uniform layer is circumferentially applied using
either pressure, or semi-pressure of tube-on tooling. Several
layers can be applied using a multiple crosshead. The cable is then
cooled in water trough sufficiently to prevent deformation of the
applied layer on the take-up reel. In cable jacketing applications,
the jacketing layer thickness can be about 20 to 100 mils with the
preferred range of about 30-80 mils. The line speeds can be equal
or greater than 150 ft/minute. All individual values and subranges
equal or greater than 150 ft/minute are included herein and
disclosed herein; for example, the line speeds can be equal or
greater than 200 ft/minute; or in the alternative, the line speeds
can be equal or greater than 300 ft/minute.
EXAMPLES
[0089] It is understood that the present invention is operable in
the absence of any component, which has not been specifically
disclosed. The following examples are provided in order to further
illustrate the invention and are not to be construed as
limiting.
[0090] The following examples illustrate that the inventive
high-density polyethylene composition has significant improvements
in processing, that is achieving significantly lower extrusion
pressures at both the breaker plate and the head. The inventive
high-density polyethylene composition further requires lower power
usage as shown by the extruder amperage. Additional significant
improvements were achieved in average surface smoothness. Improved
average surface smoothness is important because such improvements
provide for better aesthetic and customer satisfaction. Such
improvements further minimize diameter variations of the cable
jackets or installations. Where multiple extrusion layers are
involved, improved average surface smoothness can minimize the
defects at the internal interfaces. Not only did the unexpected
results of the instant invention show that inventive high-density
polyethylene composition had improved average surface smoothness,
but they have also exhibited lower shrinkage on both off-wire and
on-wire testing. Shrink-back occurs when the polymeric material
cools and the material shrinks inwards, thus exposing the end of
the metal conductor or core. Minimization of shrink-back allows for
ease of connectability by the cable installers. The following
examples show that inventive high-density polyethylene composition
possesses significant improvements over commercially available
bimodal resins as well as unimodal resins. The following examples
show that the inventive high-density polyethylene composition
possesses improved processability, smoother surface, and less
shrinkage than materials currently employed in these applications,
while maintaining at least an equal ESCR.
Inventive Samples Resins 1-6
[0091] Inventive Sample Resins 1-6 were prepared according to the
following procedures: a dual-sequential polymerization system, for
example a first gas phase reactor and a second gas phase reactor
operating in series, was provided. Ethylene, one or more
alpha-olefin comonomers, hydrogen, catalyst, for example
Ziegler-Natta catalyst, slurried in mineral oil, N.sub.2, and
isopentane were fed continuously into the first reactor.
Subsequently, a cocatalyst, for example triethylaluminum (TEAL),
was fed continuously into the first reactor to activate the
catalyst. The first polymerization reaction of the ethylene in the
presence of 1-hexene was carried out in the first reactor under the
conditions shown below in Table I thereby producing first
component-catalyst complex. The first component-catalyst complex
was continuously transferred to the second reactor. Additional,
ethylene, hydrogen, cocatalyst, for example TEAL, N.sub.2, and
isopentane were fed continuously into the second reactor. No
additional catalyst was added to the second reactor. The second
polymerization reaction of ethylene was carried out in the second
reactor under the conditions shown below in Table I thereby
producing the first component-catalyst-second component complex.
The first component-catalyst-second component complex was
continuously removed from the second reactor in batches into the
product chamber, where it was purged to remove residual
hydrocarbons, and then transferred to a fiberpak drum. The fiberpak
drum was continuously purged with humidified nitrogen. The polymer,
that is the inventive high-density polyethylene composition, was
further processed in a mixer/pelletizer. Additional additives, as
shown in Table III, were added to the polymer, that is the
inventive high-density polyethylene composition. The polymer, that
is the inventive high-density polyethylene composition, was melted
in the mixer, and additives were dispersed therein the polymer,
inventive high-density polyethylene composition, matrix. The
inventive high-density polyethylene composition was extruded
through a die plate, pelletized, and cooled. The Inventive Sample
Resins 1-6 were tested for their properties from pellets, or were
formed into testing plaques according to ASTM D-4703-00 and then
were tested for their properties. Such properties are shown in
Tables I and II, and FIGS. 1-4.
Inventive Examples 1a and 1b
[0092] The inventive high-density polyethylene composition, a
natural bimodal resin, was utilized to make the Inventive Examples
1a and 1b. The inventive high-density polyethylene composition was
applied onto 14AWG (1.6256 mm) copper wire with a targeted
thickness of 0.762 mm via extrusion process. The extruder was a
Davis-Standard wire line equipped with a 63.5 mm extruder, a 2.286
mm polyethylene metering screw, a 1.701 mm tip, and a 20/40/60/20
screen pack. The extrusion conditions are listed on Table IV. The
properties of the final cable jackets are also shown on Tables IV,
and V.
Comparative Examples A-D
[0093] Comparative Example A is a unimodal high-density
polyethylene, which is commercially available under the tradename
DGDL-3364 Natural from The Dow Chemical Company, USA. Comparative
Example B is a unimodal high-density polyethylene, which is
commercially available under the tradename DFNA-4518 natural from
The Dow Chemical Company, USA. Comparative Example C is bimodal
high-density polyethylene, which is commercially available under
the tradename DGDA 2490 Natural from The Dow Chemical Company, USA.
Comparative Example D is a bimodal high-density polyethylene, which
is commercially available under the tradename DGDA-1310 Natural
from The Dow Chemical Company, USA. Comparative Example A-D were
applied onto 14AWG (1.6256 mm) copper wire with a targeted
thickness of 0.762 mm via extrusion process. The extruder was a
Davis-Standard wire line equipped with a 63.5 mm extruder, a 2.286
mm polyethylene metering screw, a 1.701 mm tip, and a 20/40/60/20
screen pack. The extrusion conditions are listed on Table IV. The
properties of the final comparative cable jackets are also shown on
Tables IV and V.
Inventive Examples 1a-b Versus Comparative Examples A-D
[0094] The results shown on Tables IV and V are unexpected.
Inventive Examples 1a-b showed significantly lower extrusion
pressures at the breaker plate and the head at a line rate of 200
rpm than the Comparative Examples A, B, C, or D. Furthermore,
increasing the line rate by 50 percent to 300 rpm showed only a
marginal increase in pressures; however, the extrusion pressure was
still significantly lower than the Comparative Examples A, B, C, or
D, which were made at 200 rpm.
[0095] Additionally, extrusion amperage showed significantly less
power is required to process the inventive high-density
polyethylene composition even when the line rate was increased by
50 percent to 300 rpm.
[0096] The surface smoothness of Inventive Examples 1a-b, and
Comparative Examples A-D was measured according to ANSI 1995 via a
Surftest SV-400 Series 178 Surface Texture Measuring Instrument.
Wire sample was placed in a V-Block and the stylus (10 um) was
lowered down to a specific start position (approx. 1 gram force was
applied to wire). At a fixed rate of 2 mm/sec the stylus moved in
the transverse direction taking measurements. Four readings per
wire sample and four samples were tested which were then
averaged.
[0097] In addition, the shrink-back on-wire and off-wire was
measured. The shrink-back test was conducted by cutting 10 six inch
length samples from a wire sample 24 hours after extrusion. The
samples were then put on a tray which contains a layer of Talc. The
tray was then placed in an oven, which was set at a temperature of
115.degree. C. After four hours, the samples were then removed, and
allowed to cool to room temperature. The samples were then
measured, and then, the shrink-back was calculated in terms of
percentage difference from the initial six inch length. The 10
samples were then averaged. In on-wire shrinkage testing, the
copper wire was left in the test sample. In off-wire shrink-back
testing, the copper wire was removed prior to testing. The results
for the Inventive Examples 1a-b and Comparative Examples A-D are
shown in Tables IV and V.
[0098] Finally, surface average smoothness and shrink-back were
further improved when the line speed was increased by 50 percent to
300 rpm.
Inventive Example 2
[0099] The inventive high-density polyethylene composition was dry
blended with a 45 percent containing carbon black masterbatch,
which is commercially available under the tradename DFNA-0037 BN
from The Dow Chemical Company, to achieve a cable jacket comprising
2.5 percent by weight of carbon black based on the weight of the
compounded inventive high-density polyethylene composition. The
blend was applied onto 14AWG (1.6256 mm) copper wire with a
targeted thickness of 0.762 mm via extrusion process thereby
producing Inventive Example 2. The extruder was a Davis-Standard
wire line equipped with a 63.5 mm extruder, a 2.286 mm polyethylene
metering screw, a 1.701 mm tip, and a 20/40/60/20 screen pack. The
extrusion conditions are listed on Table VI. The properties of the
final cable jackets are also shown on Tables VI and VII.
Comparative Examples E1-G2
[0100] Comparative Examples E1-2 include a unimodal high-density
polyethylene, which was dry blended with a 45 percent containing
carbon black masterbatch, commercially available under the
tradename DFNA-0037 BN from The Dow Chemical Company, USA, to
achieve a cable jacket comprising 2.5 percent by weight of carbon
black based on the weight of the compounded unimodal high-density
polyethylene. Comparative Examples F1-2 include a bimodal
high-density polyethylene, commercially available under the
tradename DGDA 2490 Natural from The Dow Chemical Company, USA,
which was dry blended with a 45 percent containing carbon black
masterbatch, commercially available under the tradename DFNA-0037
BN from The Dow Chemical Company, USA, to achieve a cable jacket
comprising 2.5 percent by weight of carbon black based on the
weight of the compounded unimodal high-density polyethylene.
Comparative Examples G1-2 include a bimodal high-density
polyethylene, which is commercially available under the tradename
DGDA-1310 Natural from The Dow Chemical Company, which was dry
blended with a 45 percent containing carbon black masterbatch,
commercially available under the tradename DFNA-0037 BN from The
Dow Chemical Company, USA, to achieve a cable jacket comprising 2.5
percent by weight of carbon black based on the weight of the
compounded unimodal high-density polyethylene. The blends as
described above were applied onto 14AWG (1.6256 mm) copper wire
with a targeted thickness of 0.762 mm via extrusion process thereby
forming Comparative Examples E1-G2. The extruder was a
Davis-Standard wire line equipped with a 63.5 mm extruder, a 2.286
mm polyethylene metering screw, a 1.701 mm tip, and a 20/40/60/20
screen pack. The extrusion conditions are listed on Table VI. The
properties of the final comparative cable jackets are also shown on
Tables VI and VII.
Inventive Example 2 Versus Comparative Examples E1-G2
[0101] The results shown on Tables VI and VII are unexpected.
Inventive Example 2 showed significantly lower extrusion pressures
at the breaker plate and the head at a line rate of 200 rpm than
the Comparative Examples E1-G2. Furthermore, decreasing the line
rate by 50 percent to 100 rpm for the Comparative Examples E2, F2,
and G3 did not lower the extruder amperage to the level of Example
2.
[0102] The surface smoothness of Inventive Example 2, and
Comparative Examples E1-G2 was measured according to ANSI 1995 via
a Surftest SV-400 Series 178 Surface Texture Measuring Instrument.
Wire sample was placed in a V-Block and the stylus (10 um) was
lowered down to a specific start position (approx. 1 gram force was
applied to wire). At a fixed rate of 2 mm/sec the stylus moved in
the transverse direction taking measurements. Four readings per
wire sample and four samples were tested which were then
averaged.
[0103] In addition the shrink-back on-wire and off-wire was
measured. The shrink-back test was conducted by cutting 10 six inch
length samples from a wire sample 24 hours after extrusion. The
samples were then put on a tray which contains a layer of Talc. The
tray was then placed in an oven, which was set at a temperature of
115.degree. C. After four hours, the samples were then removed, and
allowed to cool to room temperature. The samples were then
measured, and then, the shrink-back was calculated in terms of
percentage difference from the initial six inch length. The 10
samples were then averaged. In on-wire shrinkage testing, the
copper wire was left in the test sample. In off-wire shrink-back
testing, the copper wire was removed prior to testing. The results
for the Inventive Example 2 and Comparative Examples E1-G2 are
shown in Table V.
Inventive Example 3
[0104] The inventive high-density polyethylene composition was dry
blended with a 45 percent containing carbon black masterbatch,
commercially available under the tradename DFNA-0037 BN from The
Dow Chemical Company, to achieve cable jacket comprising 2.5
percent by weight of carbon black based on the weight of the
compounded Inventive high-density polyethylene composition. The
blend was applied onto 14 AWG (1.6256 mm) copper wire with a
targeted thickness of 0.762 mm via extrusion process thereby
producing Inventive Example 3. The extruder was a Davis-Standard
wire line equipped with a 63.5 mm extruder, a 2.286 mm polyethylene
metering screw, a 1.701 mm tip, and a 20/40/60/20 screen pack. The
extrusion conditions are listed on Table VIII. The properties of
the final cable jackets are also shown on Table VIII.
Comparative Examples H-J
[0105] Comparative Example H is a high-density polyethylene jacket
compound, which is commercially available under the tradename
DGDA-6318 Black from The Dow Chemical Company, USA. Comparative
Example I is a black bimodal high-density polyethylene compound,
commercially available under the tradename Borstar HE6062 from
Borealis, Denmark. Comparative Example J is a black bimodal
high-density polyethylene jacket compound, which is commercially
available under the tradename DGDK-3479 Black from The Dow Chemical
Company, USA. Comparative Examples H-I were applied onto 14AWG
(1.6256 mm) copper wire with a targeted thickness of 0.762 mm via
extrusion process. The extruder was a Davis-Standard wire line
equipped with a 63.5 mm extruder, a 2.286 mm polyethylene metering
screw, a 1.701 mm tip, and a 20/40/60/20 screen pack. The extrusion
conditions are listed on Table VI. The properties of the final
comparative cable jackets are also shown on Table VI.
Inventive Example 3 Versus Comparative Examples H-J
[0106] The results shown on Table VIII are unexpected. Inventive
Example 3 showed significantly lower extrusion pressures at the
breaker plate and the head at a line rate of 200 rpm than the
Comparative Examples H-J.
[0107] The surface smoothness of Inventive Example 3, and
Comparative Examples H-J was measured according to ANSI 1995 via a
Surftest SV-400 Series 178 Surface Texture Measuring Instrument, as
described above.
[0108] In addition, the shrink-back on-wire and off-wire was
measured, as described above. The results for the Inventive Example
3 and Comparative Examples H-J are shown in Table VIII.
Test Methods
[0109] Unless otherwise noted, the values reported herein were
determined according to the following test methods.
[0110] Density (g/cm.sup.3) was measured according to ASTM-D
792-03, Method B, in isopropanol. Specimens were measured within 1
hour of molding after conditioning in the isopropanol bath at
23.degree. C. for 8 min to achieve thermal equilibrium prior to
measurement. The specimens were compression molded according to
ASTM D-4703-00 Annex A with a 5 min initial heating period at about
190.degree. C. and a 15.degree. C./min cooling rate per Procedure
C. The specimen was cooled to 45.degree. C. in the press with
continued cooling until "cool to the touch."
[0111] Melt index (I.sub.2) was measured at 190.degree. C. under a
load of 2.16 kg according to ASTM D-1238-03.
[0112] Melt index (I.sub.5) was measured at 190.degree. C. under a
load of 5.0 kg according to ASTM D-1238-03.
[0113] Melt index (I.sub.10) was measured at 190.degree. C. under a
load of 10.0 kg according to ASTM D-1238-03.
[0114] Melt index (I.sub.21.6) was measured at 190.degree. C. under
a load of 21.6 kg according to ASTM D-1238-03.
[0115] Weight average molecular weight (M.sub.w) and number average
molecular weight (M.sub.w) were determined according to methods
known in the art using conventional GPC, as described herein
below.
[0116] The molecular weight distributions of ethylene polymers were
determined by gel permeation chromatography (GPC). The
chromatographic system consisted of a Waters (Millford, Mass.)
150.degree. C. high temperature gel permeation chromatograph,
equipped with a Precision Detectors (Amherst, Mass.) 2-angle laser
light scattering detector Model 2040. The 15.degree. angle of the
light scattering detector was used for calculation purposes. Data
collection was performed using Viscotek TriSEC software version 3
and a 4-channel Viscotek Data Manager DM400. The system was
equipped with an on-line solvent degas device from Polymer
Laboratories. The carousel compartment was operated at 140.degree.
C. and the column compartment was operated at 150.degree. C. The
columns used were four Shodex HT 806M 300 mm, 13 .mu.m columns and
one Shodex HT803M 150 mm, 12 .mu.m column. 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
contained 200 .mu.g/g of butylated hydroxytoluene (BHT). Both
solvent sources were nitrogen sparged. Polyethylene samples were
stirred gently at 160.degree. C. for 4 hours. The injection volume
used was 200 microliters, and the flow rate was 0.67
milliliters/min. Calibration of the GPC column set was performed
with 21 narrow molecular weight distribution polystyrene standards,
with molecular weights ranging from 580 to 8,400,000 g/mol, which
were arranged in 6 "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/mol, and 0.05 grams in 50 milliliters of solvent
for molecular weights less than 1,000,000 g/mol. The polystyrene
standards were dissolved at 80.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 weights using the following
equation (as described in Williams and Ward, J. Polym. Sci., Polym.
Let., 6, 621 (1968)):
Mpolyethylene=A.times.(Mpolystyrene).sup.B,
where M is the molecular weight, A has a value of 0.41 and B is
equal to 1.0. The Systematic Approach for the determination of
multi-detector offsets was done in a manner consistent with that
published by Balke, Mourey, et al. (Mourey and Balke,
Chromatography Polym. Chpt 12, (1992) and Balke, Thitiratsakul,
Lew, Cheung, Mourey, Chromatography Polym. Chpt 13, (1992)),
optimizing dual detector log results from Dow broad polystyrene
1683 to the narrow standard column calibration results from the
narrow standards calibration curve using in-house software. The
molecular weight data for off-set determination was obtained in a
manner consistent with that published by Zimm (Zimm, B. H., J.
Chem. Phys., 16, 1099 (1948)) and Kratochvil (Kratochvil, P.,
Classical Light Scattering from Polymer Solutions, Elsevier,
Oxford, NY (1987)). The overall injected concentration used for the
determination of the molecular weight was obtained from the sample
refractive index area and the refractive index detector calibration
from a linear polyethylene homopolymer of 115,000 g/mol molecular
weight, which was measured in reference to NIST polyethylene
homopolymer standard 1475. The chromatographic concentrations were
assumed low enough to eliminate addressing 2.sup.nd Virial
coefficient effects (concentration effects on molecular weight).
Molecular weight calculations were performed using in-house
software. The calculation of the number-average molecular weight,
weight-average molecular weight, and z-average molecular weight
were made according to the following equations, assuming that the
refractometer signal is directly proportional to weight fraction.
The baseline-subtracted refractometer signal can be directly
substituted for weight fraction in the equations below. Note that
the molecular weight can be from the conventional calibration curve
or the absolute molecular weight from the light scattering to
refractometer ratio. An improved estimation of z-average molecular
weight, the baseline-subtracted light scattering signal can be
substituted for the product of weight average molecular weight and
weight fraction in equation (2) below:
a ) Mn _ = i Wf i i ( Wf i / M i ) b ) Mw _ = i ( Wf i * M i ) i Wf
i c ) Mz _ = i ( Wf i * M i 2 ) i ( Wf i * M i ) ( 2 )
##EQU00001##
[0117] Bimodality of distributions was characterized according to
the weight fraction of the highest temperature peak in temperature
rising elution fractionation (typically abbreviated as "TREF") data
as described, for example, in Wild et al., Journal of Polymer
Science, Poly. Phys. Ed., Vol. 20, p. 441 (1982), in U.S. Pat. No.
4,798,081 (Hazlitt et al.), or in U.S. Pat. No. 5,089,321 (Chum et
al.), the disclosures of all of which are incorporated herein by
reference. In analytical temperature rising elution fractionation
analysis (as described in U.S. Pat. No. 4,798,081 and abbreviated
herein as "ATREF"), the composition to be analyzed is dissolved in
a suitable hot solvent (for example, 1,2,4 trichlorobenzene), and
allowed to crystallized in a column containing an inert support
(for example, stainless steel shot) by slowly reducing the
temperature. The column was equipped with both an infra-red
detector and a differential viscometer (DV) detector. An ATREF-DV
chromatogram curve was then generated by eluting the crystallized
polymer sample from the column by slowly increasing the temperature
of the eluting solvent (1,2,4 trichlorobenzene). The ATREF-DV
method is described in further detail in WO 99/14271, the
disclosure of which is incorporated herein by reference.
[0118] High Density Fraction (percent) was measured via analytical
temperature rising elution fractionation analysis (as described in
U.S. Pat. No. 4,798,081 and abbreviated herein as "ATREF"), which
is described in further details hereinafter. Analytical temperature
rising elution fractionation (ATREF) analysis was conducted
according to the method described in U.S. Pat. No. 4,798,081 and
Wilde, L.; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.;
Determination of Branching Distributions in Polyethylene and
Ethylene Copolymers, J. Polym. Sci., 20, 441-455 (1982), which are
herein in their entirety. The composition to be analyzed was
dissolved in trichlorobenzene and allowed to crystallize in a
column containing an inert support (stainless steel shot) by slowly
reducing the temperature to 20.degree. C. at a cooling rate of
0.1.degree. C./min. The column was equipped with an infrared
detector. An ATREF chromatogram curve was then generated by eluting
the crystallized polymer sample from the column by slowly
increasing the temperature of the eluting solvent
(trichlorobenzene) from 20 to 120.degree. C. at a rate of
1.5.degree. C./min.
[0119] Branching distributions were determined via crystallization
analysis fractionation (CRYSTAF); described herein below.
Crystallization analysis fractionation (CRYSTAF) was conducted via
a CRYSTAF 200 unit commercially available from PolymerChar,
Valencia, Spain. The samples were dissolved in 1,2,4
trichlorobenzene at 160.degree. C. (0.66 mg/mL) for 1 hr and
stabilized at 95.degree. C. for 45 minutes. The sampling
temperatures ranged from 95 to 30.degree. C. at a cooling rate of
0.2.degree. C./min. An infrared detector was used to measure the
polymer solution concentrations. The cumulative soluble
concentration was measured as the polymer crystallizes while the
temperature was decreased. The analytical derivative of the
cumulative profile reflects the short chain branching distribution
of the polymer.
[0120] The CRYSTAF temperature peak and area are identified by the
peak analysis module included in the CRYSTAF Software (Version
2001.b, PolymerChar, Valencia, Spain). The CRYSTAF peak finding
routine identifies a temperature peak as a maximum in the dW/dT
curve and the area between the largest positive inflections on
either side of the identified peak in the derivative curve. To
calculate the CRYSTAF curve, the preferred processing parameters
are with a temperature limit of 70.degree. C. and with smoothing
parameters above the temperature limit of 0.1, and below the
temperature limit of 0.3.
[0121] Solubility Distribution Breadth Index (SDBI) is the
statistical value for the breadth of the CRYSTAF method which is
calculated based on the following formula:
SDBI=.intg.{square root over ((T-T.sub.w).sup.4w(T)dT)}{square root
over ((T-T.sub.w).sup.4w(T)dT)}
T.sub.w=.intg.Tw(T)dT
.intg.w(T)dT=1
wherein T is temperature, W is weight fraction, and T.sub.w weight
average temperature.
[0122] Long Chain Branching was determined according to the methods
known in the art, such as gel permeation chromatography coupled
with low angle laser light scattering detector (GPC-LALLS) and gel
permeation chromatography coupled with a differential viscometer
detector (GPC-DV).
[0123] Resin stiffness was characterized by measuring the Flexural
Modulus at 5 percent strain and Secant Modulii at 1 percent and 2
percent strain, and a test speed of 0.5 inch/min (13 mm/min)
according to ASTM D 790-99 Method B.
[0124] Tensile strength at yield and elongation at break were
measured according to ASTM D-638-03 employing Type IV Specimen at 2
inch/minute (50 mm/minute).
[0125] The environmental stress crack resistance (ESCR) was
measured according to ASTM-D 1693-01, Condition B. The
susceptibility of the resin to mechanical failure by cracking was
measured under constant strain conditions, and in the presence of a
crack accelerating agent such as soaps, wetting agents, etc.
Measurements were carried out on notched specimens, in a 10
percent, by volume, Igepal CO-630 (vendor Rhone-Poulec, NJ) aqueous
solution, maintained at 50.degree. C., and a 100 percent, by
volume, Igepal CO-630 (vendor Rhone-Poulec, NJ) aqueous solution,
maintained at 50.degree. C. The ESCR value was reported as
F.sub.50, the calculated 50 percent failure time from the
probability graph, and F.sub.0, where there are no failures in the
trial.
[0126] Short chain branching distribution and comonomer content was
measured using C.sub.13 NMR, as discussed in Randall, Rev.
Macromol. Chem. Chys., C29 (2&3), pp. 285-297, and in U.S. Pat.
No. 5,292,845, the disclosures of which are incorporated herein by
reference to the extent related to such measurement. The samples
were prepared by adding approximately 3 g of a 50/50 mixture of
tetrachloroethane-d2/orthodichlorobenzene that was 0.025M in
chromium acetylacetonate (relaxation agent) to 0.4 g sample in a 10
mm NMR tube. The samples were dissolved and homogenized by heating
the tube and its contents to 150.degree. C. The data was collected
using a JEOL Eclipse 400 MHz NMR spectrometer, corresponding to a
13C resonance frequency of 100.6 MHz. Acquisition parameters were
selected to ensure quantitative 13C data acquisition in the
presence of the relaxation agent. The data was acquired using gated
1H decoupling, 4000 transients per data file, a 4.7 sec relaxation
delay and 1.3 second acquisition time, a spectral width of 24,200
Hz and a file size of 64K data points, with the probe head heated
to 130.degree. C. The spectra were referenced to the methylene peak
at 30 ppm. The results were calculated according to ASTM method
D5017-91.
[0127] The resin rheology was measured on the ARES I (Advanced
Rheometric Expansion System) Rheometer. The ARES I was a strain
controlled rheometer. A rotary actuator (servomotor) applied shear
deformation in the form of strain to a sample. In response, the
sample generated torque, which was measured by the transducer.
Strain and torque were used to calculate dynamic mechanical
properties, such as modulus and viscosity. The viscoelastic
properties of the sample were measured in the melt using a 25 mm in
diameter parallel plate set up, at constant strain (5 percent) and
temperature (190.degree. C.) and N.sub.2 purge, and as a function
of varying frequency (0.01 to 500 s.sup.-1). The storage modulus,
loss modulus, tan delta, and complex viscosity of the resin were
determined using Rheometrics Orchestrator software (v. 6.5.8). The
viscosity ratio (0.1 rad*s.sup.-1/100 rad*s.sup.-1) was determined
to be the ratio of the viscosity measured at a shear rate of 0.1
rad/s to the viscosity measured at a shear rate of 100 rad/s.
[0128] Vinyl unsaturations were measured according to ASTM
D-6248-98.
[0129] Low shear rheological characterization is performed on a
Rheometrics SR5000 in stress controlled mode, using a 25 mm
parallel plates fixture. This type of geometry is preferred to cone
and plate because it requires only minimal squeezing flow during
sample loading, thus reducing residual stresses.
[0130] g' average was determined according to the following
procedure. The chromatographic system consisted of a Waters
(Millford, Mass.) 150.degree. C. high temperature chromatograph
equipped with a Precision Detectors (Amherst, Mass.) 2-angle laser
light scattering detector Model 2040, an IR4 infra-red detector
from Polymer Char (Valencia, Spain), and a Viscotek (Houston, Tex.)
150R 4-capillary viscometer. The 15-degree angle of the light
scattering detector was used for calculation purposes. Data
collection was performed using Viscotek TriSEC software version 3
and a 4-channel Viscotek Data Manager DM400. The system was
equipped with an on-line solvent degas device from Polymer
Laboratories. The carousel compartment was operated at 140.degree.
C. and the column compartment was operated at 150.degree. C. The
columns used were 4 20-micron mixed-bed light scattering "Mixed
A-LS" columns from Polymer Laboratories. 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
contained 200 ppm of butylated hydroxytoluene (BHT). Both solvent
sources were nitrogen sparged. Polyethylene samples were stirred
gently at 160 degrees Celsius for 4 hours. The injection volume
used was 200 microliters and the flow rate was 1
milliliters/minute.
[0131] 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, and were arranged
in 6 "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, and 0.05
grams in 50 milliliters of solvent for molecular weights less than
1,000,000. 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 weights using the following equation (as described in
Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621
(1968)).:
Mpolyethylene=A.times.(Mpolystyrene).sup.B
Where M is the molecular weight, A has a value of 0.43 and B is
equal to 1.0.
[0132] The Systematic Approach for the determination of
multi-detector offsets was done in a manner consistent with that
published by Balke, Mourey, et. al. (Mourey and Balke,
Chromatography Polym. Chpt 12, (1992)) (Balke, Thitiratsakul, Lew,
Cheung, Mourey, Chromatography Polym. Chpt 13, (1992)), optimizing
triple detector log (MW and IV) results from Dow Broad Polystyrene
1683 to the narrow standard column calibration results from the
narrow standards calibration curve using a software. The molecular
weight data for off-set determination was obtained in a manner
consistent with that published by Zimm (Zimm, B. H., J. Chem.
Phys., 16, 1099 (1948)) and Kratochvil (Kratochvil, P., Classical
Light Scattering from Polymer Solutions, Elsevier, Oxford, NY
(1987)). The overall injected concentration used for the
determination of the molecular weight was obtained from the sample
refractive index area and the refractive index detector calibration
from a linear polyethylene homopolymer of 115,000 molecular weight.
The chromatographic concentrations were assumed low enough to
eliminate addressing 2.sup.nd Virial coefficient effects
(concentration effects on molecular weight).
[0133] g' average was calculated for the samples as follow:
[0134] 1. The light scattering, viscosity, and concentration
detectors were calibrated with NBS 1475 homopolymer polyethylene
(or equivalent reference);
[0135] 2. The light scattering and viscometer detector offsets
relative to the concentration detector was corrected as described
in the calibration section;
[0136] 3. Baselines were subtracted from the light scattering,
viscometer, and concentration chromatograms and set integration
windows making certain to integrate all of the low molecular weight
retention volume range in the light scattering chromatogram that
were observable from the refractometer chromatogram;
[0137] 4. A linear homopolymer polyethylene Mark-Houwink reference
line was established by injecting a standard with a polydispersity
of at least 3.0, and the data file (from above calibration method),
was calculated and the intrinsic viscosity and molecular weight
from the mass constant corrected data for each chromatographic
slice was recorded;
[0138] 5. The HDPE sample of interest was injected and the data
file (from above calibration method), was calculated and the
intrinsic viscosity and molecular weight from the mass constant
corrected data for each chromatographic slice was recorded;
[0139] 6. The homopolymer linear reference intrinsic viscosity was
shifted by the following factor: IV=IV+1/(1+2*SCB/1,000 C*branch
point length) where IV is the intrinsic viscosity of the HDPE
sample of interest, SCB/1,000 C was determined from C13 NMR, and
the branch point length is 2 for butene, 4 for hexene, or 6 for
octene);
[0140] 7. g' average was calculated according to the following
equation.
g ' = j = WhereM > 40 , 000 HighestM [ c j .times. ( IV j IV Lj
) M ] + j = LowestM WhereM > 40 , 000 c j j = LowestM HighestM c
j ##EQU00002##
Where c is the concentration of the slice, IV is the intrinsic
viscosity of the HDPE, and IV.sub.L is the intrinsic viscosity of
the linear homopolymer polyethylene reference (corrected for SCB of
the HDPE sample of interest) at the same molecular weight (M). The
IV ratio was assumed to be one at molecular weights less than
40,000 to account for natural scatter in the light scattering
data.
[0141] Surface average smoothness was determined via a Surftest
SV-400 Series 178 Surface Texture Measuring Instrument according to
ANSI 1995. The wire sample was placed in a V-Block and the stylus
(10 um) was lowered down to a specific start position (approx. 1
gram force was applied to wire). At a fixed rate of 2 mm/sec the
stylus moved in the transverse direction taking measurements. Four
readings per wire sample and four samples were tested which are
then averaged.
[0142] The shrink-back on-wire and off-wire was determined
according to the following procedure. The shrink-back test was
conducted by cutting 10 six inch length samples from a wire sample
24 hours after extrusion. The samples were then put on a tray which
contains a layer of Talc. The tray was then placed in an oven,
which was set at a temperature of 115.degree. C. After four hours,
the samples were then removed, and allowed to cool to room
temperature. The samples were then measured, and then, the
shrink-back was calculated in terms of percentage difference from
the initial six inch length. The 10 samples were then averaged. In
on-wire shrinkage testing, the copper wire was left in the test
sample. In off-wire shrink-back testing, the copper wire was
removed prior to testing.
[0143] The present invention may be embodied in other forms without
departing from the spirit and the essential attributes thereof,
and, accordingly, reference should be made to the appended claims,
rather than to the foregoing specification, as indicating the scope
of the invention.
TABLE-US-00001 TABLE I Inventive Sample Resin No. 1 2 3 4 5 6
Co-Monomer Type 1-hexene 1-hexene 1-hexene 1-hexene 1-hexene
1-hexene Catalyst Ziegler-Natta Ziegler-Natta Ziegler-Natta
Ziegler-Natta Ziegler-Natta Ziegler-Natta Co-Catalyst 2.5% TEAL
2.5% TEAL 2.5% TEAL 2.5% TEAL 2.5% TEAL 2.5% TEAL 1.sup.st Reactor
Type Gas Phase Gas Phase Gas Phase Gas Phase Gas Phase Gas Phase
2.sup.nd Reactor Type Gas Phase Gas Phase Gas Phase Gas Phase Gas
Phase Gas Phase 1.sup.st Reaction Temperature (.degree. C.) 85 85
85 85 85 85 2.sup.nd Reaction Temperature (.degree. C.) 109.9 110
110 110 110 110 1.sup.st Reaction Pressure (psi) 349 349 349 349
348 348 2.sup.nd Reaction Pressure (psi) 403 405 405 402 404 394
1.sup.st Reactor C.sub.2 Partial Pressure (psi) 23.2 22.6 26.3 24.9
20.7 26.1 2.sup.nd Reactor C.sub.2 Partial Pressure (psi) 93.7 97.2
100.6 100.8 104.1 81.1 1.sup.st Reactor H.sub.2/C.sub.2 Molar Ratio
0.082 0.060 0.093 0.080 0.052 0.115 2.sup.nd Reactor
H.sub.2/C.sub.2 Molar Ratio 1.80 1.802 1.805 1.127 1.799 1.799
1.sup.st Reactor C.sub.6/C.sub.2 Molar Ratio 0.062 0.1049 0.0253
0.0635 0.0918 0.0463 2.sup.nd Reactor C.sub.6/C.sub.2 Molar Ratio
0.004 0.0051 0.0050 0.0036 0.0021 0.0029 Catalyst Feed Rate (cc/hr)
3.2 5.2 5.7 5.4 7.2 6 (First Reactor Only) 1.sup.st Reactor
Isopentane (Mole %) 8.6 8.7 8.0 7.4 7.4 8.8 2.sup.nd Reactor
Isopentane (Mole %) 4.0 4.4 3.5 2.8 2.6 3.4
TABLE-US-00002 TABLE II Inventive Sample Resin No. 1 2 3 4 5 6
Split (1.sup.st reactor/2.sup.nd reactor) 0.448/0.552 0.472/0.528
0.484/0.516 0.460/0.540 0.427/0.573 0.559/0.441 Cocatalyst Feed
Rate (cc/hr) (1.sup.st reactor/ 161/161 161/158 162/154 162/154
171/170 162/134 2.sup.nd reactor) Production Rate (lb/hr) (1.sup.st
reactor/2.sup.nd 24.0/21.3 24/21 24/21 24/23 25/27 25/17 reactor)
Bed Weight (lbs) (1.sup.st reactor/2.sup.nd reactor) 75.6/135.7
76/122 75/119 75/120 76/120 78/137 FBD (lb/ft.sup.3) (1.sup.st
reactor/2.sup.nd reactor) 11.1/16.3 11.1/16.4 11.7/17.4 11.3/16.5
11.1/17.0 11.6/16.4 Bed Volume (ft.sup.3) (1.sup.st
reactor/2.sup.nd reactor) 6.8/8.3 6.8/7.4 6.4/6.8 6.7/7.3 6.8/7.1
6.8/8.3 Residence Time (hr) (1.sup.st reactor/2.sup.nd reactor)
3.1/3.0 3.2/2.7 3.1/2.6 3.1/2.6 3.1/2.3 3.1/3.3 STY
(lb/hr/ft.sup.3) (1.sup.st reactor/2.sup.nd reactor) 3.5/2.6
3.5/2.8 3.7/3.1 3.6/3.2 3.6/3.8 3.7/2.0 Melt index (I.sub.21)
(1.sup.st Component) (~) (g/10 2.28 2.25 2.04 2.41 1.36 3.96
minutes) Density (1.sup.st Component) (~) (g/cm.sup.3) 0.9282
0.9221 0.9360 0.9292 0.9227 0.9336 Residual Ti (ppm) (1.sup.st
component/2.sup.nd component) 3.76/1.63 3.15/1.61 3.66/1.61
3.33/1.52 3.99/1.56 3.66/1.99 Residual Al (ppm) (1.sup.st
component/2.sup.nd component) 97.5/48.2 99.63/58.37 101.00/49.25
94.30/49.42 105.69/48.22 102.34/56.70 Al/Ti Molar Residual Ti (ppm)
(1.sup.st component/ 47.4/52.8 56/65 49/55 51/54 47/56 50/51
2.sup.nd component) Bulk Density (lb/ft.sup.3) Residual Ti (ppm)
(1.sup.st 17.8/25.0 16.7/24.1 20.1/25.6 17.6/24.5 17.0/24.8
18.3/24.8 component/2.sup.nd component) H-D Polyethylene
Composition Melt Index (I.sub.2) 1.48 1.46 1.39 1.66 1.31 1.58
(2.16 g/10 minutes) H-D Polyethylene Composition Melt Index
(I.sub.5) 5.89 5.99 4.96 6.06 5.69 5.58 (5.0 g/10 minutes) H-D
Polyethylene Composition Melt Index (I.sub.10) 26.3 23.5 20.1 20.6
23.5 19.6 (10.0 g/10 minutes) H-D Polyethylene Composition Melt
Index (I.sub.21.6) 139.7 162.0 133.6 108.6 179.5 108.0 (21.6 g/10
minutes) H-D Polyethylene Composition Melt Flow Ratio 94.2 111.0
96.5 65.3 137.1 68.5 (MI.sub.21/MI.sub.2) H-D Polyethylene
Composition Melt Flow Ratio 23.7 27.0 26.9 17.9 31.5 19.3
(MI.sub.21/MI.sub.5) H-D Polyethylene Composition Melt Flow Ratio
17.7 16.1 14.5 12.4 17.9 12.5 (MI.sub.10/MI.sub.2) H-D Polyethylene
Composition Density (g/cm.sup.3) 0.9548 0.9506 0.9591 0.9548 0.9546
0.955 ASTM Slow cooled C13 NMR Hexene Content (Weight Percent) 1.5
2.9 0.9 1.3 1.8 1.4 H-D Polyethylene Composition (M.sub.n) 8,125
8,920 9,310 14,500 10,500 11,700 H-D Polyethylene Composition
(M.sub.w) 124,600 133,300 135,000 136,000 130,400 133,000 H-D
Polyethylene Composition (M.sub.w/M.sub.n) 15.3 14.9 14.5 9.4 12.4
11.4 g' 1.007 -- -- -- -- -- Atref HD Fraction (%) 70.8 58.4 74.1
67.4 55.9 71 Calculated Atref HD Fraction (%) 36.8 28.9 43.3 36.7
27.7 41.3 Atref Purge fraction (%) 15.2 21.4 21 27.4 19.6 18.3
Atref SCBD Fraction (%) (27 to 86.degree. C.) 14 20.2 4.9 5.2 24.5
10.7 Atref MV average 58,100 53,800 63,000 63,400 49,400 56,700
Atref SCBD Mv 58,100 56,600 68,600 68,400 51,100 60,400 Atref Purge
Mv 58,050 43,600 41,800 46,700 42,750 40,200 Viscosity at 10 - 2
sec - 1 Shear Rate 11,580 13,700 12,900 11,200 17,000 11,200 (Pa S)
Viscosity at 10 + 2 sec - 1 Shear Rate 805 834 903 918 828 952 (Pa
S) Ratio 10 - 2/10 + 2 14.4 16.4 14.3 12.2 20.5 11.8 Tan Delta @ 10
- 2 7.6 6.98 7.61 8.1 5.67 8.51 Tan Delta @ 10 + 2 0.828 0.79 0.81
0.94 0.76 0.88 Rheotens Melt Strength (cN) 2.5 2.5 2.5 2.5 3 2.5
Rheotens Melt Strength (velocity mm/s) 212 200 210 205 170-200 225
Flexural Modulus (0.5 in/min) (psi) 218,000 187,000 243,000 217,000
221,000 236,000 Standard Deviation (+/-) 7,723 9,400 15,000 10,000
13,400 10,000 2% Secant Modulus (psi) 163,000 138,000 169,000
157,000 157,000 160,000 Standard Deviation (+/-) 3,470 5,660 3,300
6,900 1,900 4,400 1% Secant Modulus (psi) 193,500 164,000 203,000
186,400 188,000 193,000 Standard Deviation (+/-) 5,246 8,570 5,700
9,550 1,500 5,250 Tensile Properties (ave thickness, mils) Tensile
Strength (psi) 2,600 2,500 2,550 3,250 3,050 2,650 Standard
Deviation (+/-) 307 160 260 630 440 100 Elongation at Break (%) 510
480 720 720 630 740 Standard Deviation (+/-) 227 145 200 225 85
Yield Strength (psi) 3,535 3,048 3,750 3,500 3,600 3,600 Standard
Deviation (+/-) 135 160 150 140 220 105 Elongation at Yield (%)
3.44 3.89 3.58 3.68 3.36 3.67 Standard Deviation (+/-) 0.68 0.41
0.33 0.41 0.49 0.28 ESCR Test Data 50.degree. C.; 10% Igepal; 75
mil plaque, 12 mil F50 = F0 > F50 = F50 = F0 > F50 = slit
(F50 hours) 509 1,188 239.9 329.4 1,188 247.1 50.degree. C.; 100%
Igepal; 75 mil plaque, 12 mil F0 > F0 > F50 = F0 > F0 >
F0 > slit (F50 hours) 2,000 1,188 1,071 1,188 1,188 1,188
Extrudability Good -- -- -- -- --
TABLE-US-00003 TABLE III Inventive Sample Resin No. 1 2 3 4 5 6
Irganox 1076 (ppm) 0 0 0 0 0 0 Irganox 1010 (ppm) 420 536 465 486
481 412 Irgafos 168 Active (ppm) 353 366 393 360 363 268 Irgafos
168 Oxidized (ppm) 120 174 114 159 158 195 Irgafos 168 Total (ppm)
473 540 507 519 521 463
TABLE-US-00004 TABLE IV Inventive Inventive Comparative Comparative
Comparative Comparative Example 1a Example 1b Example A Example B
Example C Example D Temperature (.degree. F.) Zone 1 360 360 360
360 360 360 Zone 2 380 380 380 380 380 380 Zone 3 410 410 410 410
410 410 Zone 4 420 420 420 420 420 420 Zone 5 433 440 440 440 440
440 Head 422 422 422 422 422 422 Die 460 460 460 460 460 460 Melt
419 420 420 444 471 441 Pressure (psi) Zone 5 2590 2870 3790 5185
5055 4340 Breaker 2320 2580 3250 4795 5190 4000 Head 1730 1930 2440
3550 3700 2980 Screw Amps 24.4 28.5 32.6 44 48.8 38.2 Screw Speed
(rpm) 38.3 56.7 36.8 38.5 44.3 39.5 Line Speed (ft/min) 200 300 200
200 200 200 Extruder amps 24.4 28.5 32.6 44 48.8 38.2 Average
Surface Smoothness, (micro- 11.2 10.7 22.3 53.3 57.2 20.3 inch)
Shrink-back on-wire after 24 hrs (%) 1.09 0.81 1.41 1.95 1.82 1.33
Shrink-back off-wire after 24 hrs (%) 3.39 3.1 3.57 4.43 3.59
3.41
TABLE-US-00005 TABLE V Inventive Example 1a Comparative A
Comparative B Comparative C Comparative D Density (g/cm.sup.3)
0.9566 0.9485 0.9444 0.9504 0.9556 Melt Index (I.sub.2) g/10
minutes 1.746 0.790 0.162 0.076 0.306 Melt Index (I.sub.21.6) g/10
minutes 168.405 59.756 18.541 7.714 29.478 I.sub.21.6/I.sub.2 96 76
114 101 96 Shore D Hardness 61.0 59.1 58.8 60.1 61.4 Flexural
Modulus (psi) 97,613 72,884 66,196 79,042 87,923 1% Secant Modulus
(psi) 2''/min. 349,119 264,620 257,942 278,073 303,872 Tensile @
Yield (psi) 2''/min. 3,834 3,251 3,193 3,466 3,878 Tensile @ Break
2''/min. 3,834 3,251 4,055 5,255 4,410 Elongation (%) 2''/min. 627
642 759 711 780 ESCR 50.degree. C./10% Igepal Days to break 1/27
10/3 10/9 0 0 Dielectric Constant @ 1 MHz 2.292454 2.333211 2.33668
2.328488 2.349914 Dissipation Factor @ 1 MHz 0.000106 9.73E-05
0.000135 4.66E-05 9.32E-05 Low Temperature Brittleness
<-75.degree. C. <-75.degree. C. <-75.degree. C.
<-75.degree. C. <-75.degree. C.
TABLE-US-00006 TABLE VI Inventive Comparative Comparative
Comparative Comparative Comparative Comparative Example 2 E1 E2 F1
F2 G1 Example G2 Temperature (.degree. F.) Zone 1 360 360 360 360
360 360 360 Zone 2 380 380 380 380 380 380 380 Zone 3 410 410 410
410 410 410 410 Zone 4 420 420 420 420 420 420 420 Zone 5 440 440
440 440 440 440 440 Head 422 422 422 422 422 422 422 Die 460 460
460 460 460 460 460 Melt 420 445 426 473 441 441 424 Pressure (psi)
Zone 5 2620 5055 4130 5160 4630 4395 3665 Breaker 2290 4640 3690
5240 4630 4050 3315 Head 1730 3420 2760 3750 3280 2970 2450 Screw
Amps 24 42.6 32.9 48.7 40.5 38.7 30 Screw Speed (rpm) 37.6 38 18.5
49.3 20.7 39.3 19.4 Line Speed (ft/min) 200 200 100 200 100 200 100
Extruder amps 24 42.6 32.9 48.7 40.5 38.7 30 Average Surface 11
88.8 18.1 66.5 44.4 21.9 15.6 Smoothness, (micro-in) Shrink-back
on-wire 0.86 1.9 1.61 1.88 1.67 0.99 1.46 after 24 hrs (%)
Shrink-back off-wire 3.1 4.24 4.79 3.54 3.67 3.46 3.41 after 24 hrs
(%)
TABLE-US-00007 TABLE VII Inventive Example 2 Comparative H
Comparative J Comparative I Comparative G1 Density (g/cm.sup.3)
0.9702 0.9569 0.9566 0.9582 0.9677 Melt Index (I.sub.2) g/10
minutes 1.675 0.804 0.179 0.506 0.317 Melt Index (I.sub.21.6) g/10
minutes 155.926 62.804 23.143 40.642 30.125 I.sub.21.6/I.sub.2 93
78 129 80 95 Shore D Hardness 61.6 57.9 58.2 58.3 61.6 Flexural
Modulus (psi) 98,567 65,290 66,941 69,965 102,124 1% Secant Modulus
(psi) 2''/min. 239,147 150,399 202,437 173,593 274,186 Tensile @
Yield (psi) 2''/min. 4,133 3,121 3,032 3,119 3,949 Tensile @ Break
2''/min. 4,133 3,486 4,578 4,580 3,949 Elongation (%) 2''/min. 355
808 908 821 484 ESCR 50.degree. C./10% Igepal Days to break 0 10/6
1/24 0 0 Dielectric Constant @ 1 MHz 2.608686 2.561575 2.567739
2.573513 2.604177 Dissipation Factor @ 1 MHz 0.000236 0.000228
0.000224 0.000445 0.000261 Low Temperature Brittleness
<-75.degree. C. <-75.degree. C. <-75.degree. C.
<-75.degree. C. <-75.degree. C.
TABLE-US-00008 TABLE VIII Inventive Compara- Compara- Compara-
Example 3 tive H tive I tive J Temperature (.degree. F.) Zone 1 360
360 360 360 Zone 2 380 380 380 380 Zone 3 410 410 410 410 Zone 4
420 420 420 420 Zone 5 440 440 442 442 Head 422 422 422 422 Die 460
460 460 460 Melt 420 435 434 435 Pressure (psi) Zone 5 2620 3670
4450 3670 Breaker 2290 3140 3840 3140 Head 1730 2360 2820 2360
Screw Amps 24 31 36.8 31 Screw Speed (rpm) 37.6 35.2 36.5 35.2 Line
Speed (ft/min) 200 200 200 200 Extruder amps 24 31 32.3 41 Average
Surface 11 17.9 22.5 33.2 Smoothness, (micro-inch) Shrink-back
on-wire 0.86 1.38 1.54 2.4 after 24 hrs (%) Shrink-back off-wire
3.1 3.65 3.54 4.69 after 24 hrs (%)
* * * * *