U.S. patent application number 16/220571 was filed with the patent office on 2019-06-20 for bottle closure assembly including a polyethylene copolymer.
This patent application is currently assigned to NOVA Chemicals (International) S.A.. The applicant listed for this patent is NOVA Chemicals (International) S.A.. Invention is credited to Cliff Baar, Ian Gibbons, Amin Mirzadeh, Eric Vignola, XiaoChuan Wang.
Application Number | 20190185219 16/220571 |
Document ID | / |
Family ID | 65199439 |
Filed Date | 2019-06-20 |
View All Diagrams
United States Patent
Application |
20190185219 |
Kind Code |
A1 |
Wang; XiaoChuan ; et
al. |
June 20, 2019 |
BOTTLE CLOSURE ASSEMBLY INCLUDING A POLYETHYLENE COPOLYMER
Abstract
The present disclosure describes bottle closure assemblies which
are made at least in part with a polyethylene copolymer having good
organoleptic properties. The bottle closure assembly includes a cap
portion, an elongated tether portion, and a retaining means
portion. The retaining means portions engages a bottle neck or an
upper portion of a bottle. The elongated tether portion connects at
least one point on the cap portion to at least one point on the
retaining means portion so as to prevent loss of the cap portion
from a bottle.
Inventors: |
Wang; XiaoChuan; (Calgary,
CA) ; Gibbons; Ian; (Calgary, CA) ; Vignola;
Eric; (Airdrie, CA) ; Baar; Cliff; (Calgary,
CA) ; Mirzadeh; Amin; (Calgary, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOVA Chemicals (International) S.A. |
Fribourg |
|
CH |
|
|
Assignee: |
NOVA Chemicals (International)
S.A.
Fribourg
CH
|
Family ID: |
65199439 |
Appl. No.: |
16/220571 |
Filed: |
December 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62607610 |
Dec 19, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 55/16 20130101;
B29K 2023/065 20130101; B65D 2543/00296 20130101; B29K 2105/0094
20130101; B65D 41/34 20130101; B65D 2543/00537 20130101; B29L
2031/56 20130101; B65D 41/3428 20130101 |
International
Class: |
B65D 41/34 20060101
B65D041/34 |
Claims
1. A bottle closure assembly comprising: a cap portion, a tether
portion, and a retaining means portion, the cap portion being
molded to reversibly engage and cover a bottle opening, the
retaining means portion being molded to irreversibly engage a
bottle neck or an upper portion of a bottle, and wherein the tether
portion connects at least one point on the cap portion to at least
one point on the retaining means portion, wherein the cap portion,
optionally the tether portion, and optionally the retaining means
portion are made from a polyethylene copolymer having a density of
from 0.940 to 0.962 g/cm.sup.3, a melt index 12 of less than 1.5
g/10 min, an amount of terminal unsaturation of at least 0.45 per
1000 carbon atoms, fewer than 0.9 parts per million of titanium,
and fewer than 0.4 parts per million of chromium.
2. A bottle closure assembly comprising: a cap portion, an
elongated tether portion, and a retaining means portion, the cap
portion being molded to reversibly engage and cover a bottle
opening, the retaining means portion being molded to irreversibly
engage a bottle neck or an upper portion of a bottle, and the
elongated tether portion being molded to connect at least one point
on the cap portion to at least one point on the retaining means
portion, wherein the cap portion, optionally the elongated tether
portion, and optionally the retaining means portion are made from a
polyethylene copolymer having a density of from 0.940 to 0.962
g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an amount of
terminal unsaturation of at least 0.45 per 1000 carbon atoms, fewer
than 0.9 parts per million of titanium, and fewer than 0.4 parts
per million of chromium.
3. A bottle closure assembly comprising: an integrally molded: cap
portion, tether portion, and retaining means portion; the cap
portion being molded to reversibly engage and cover a bottle
opening, the retaining means portion being molded to irreversibly
engage a bottle neck or an upper portion of a bottle, and the
tether portion being molded to connect at least one point on the
cap portion to at least one point on the retaining means portion;
wherein the integrally molded: cap portion, tether portion, and
retaining means portion are made from a polyethylene copolymer
which has a density of from 0.940 to 0.962 g/cm.sup.3, a melt index
12 of less than 1.5 g/10 min, an amount of terminal unsaturation of
at least 0.45 per 1000 carbon atoms, fewer than 0.9 parts per
million of titanium, and fewer than 0.4 parts per million of
chromium.
4. A bottle closure assembly comprising: an integrally molded: cap
portion, elongated tether portion, and retaining means portion; the
cap portion being molded to reversibly engage and cover a bottle
opening, the retaining means portion being molded to irreversibly
engage a bottle neck or an upper portion of a bottle, and the
elongated tether portion being molded to connect at least one point
on the cap portion to at least one point on the retaining means
portion; wherein the integrally molded: cap portion, elongated
tether portion, and retaining means portion are made from a
polyethylene copolymer which has a density of from 0.940 to 0.962
g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an amount of
terminal unsaturation of at least 0.45 per 1000 carbon atoms, fewer
than 0.9 parts per million of titanium, and fewer than 0.4 parts
per million of chromium.
5. A bottle closure assembly comprising: an integrally molded: cap
portion, elongated tether portion, and retaining collar portion;
the cap portion being molded to reversibly engage and cover a
bottle opening, the retaining collar portion being molded to
irreversibly engage a bottle neck or an upper portion of a bottle,
and the elongated tether portion being molded to connect at least
one point on the cap portion to at least one point on the retaining
collar portion; wherein the integrally molded: cap portion,
elongated tether portion, and retaining collar portion are made
from a polyethylene copolymer which has a density of from 0.940 to
0.962 g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an
amount of terminal unsaturation of at least 0.45 per 1000 carbon
atoms, fewer than 0.9 parts per million of titanium, and fewer than
0.4 parts per million of chromium.
6. A bottle closure assembly comprising: a closure portion, an
elongated tether portion, and a retaining collar portion, the
closure portion being molded to reversibly engage and cover a
bottle opening, the elongated tether portion comprising a tether
strip which is frangibly connected along a portion of its upper
edge to a descending annular edge of the closure portion and which
is frangibly connected along a portion of its lower edge to an
upper annular edge of the retaining collar portion, the tether
strip being integrally formed with and connected at one end to at
least one point on the closure portion and integrally formed with
and connected at another end to at least one point on the retaining
collar portion, the frangible sections being breakable when the
closure portion is removed from a bottle opening, but where the
closure portion remains connected to the retaining collar via the
tether strip; wherein the cap portion, the elongated tether
portion, and the retaining collar portion are integrally molded
from a polyethylene copolymer which has a density of from 0.940 to
0.962 g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an
amount of terminal unsaturation of at least 0.45 per 1000 carbon
atoms, fewer than 0.9 parts per million of titanium, and fewer than
0.4 parts per million of chromium.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. Provisional Application No. 62/607,610, which was filed on
Dec. 19, 2017. The contents of U.S. Provisional Application No.
62/607,610 are incorporated herein by reference in their
entirety.
TECHNICAL FIELD
[0002] The present disclosure is directed to bottle closure
assemblies which are made at least in part with a polyethylene
copolymer. The bottle closure assembly includes a cap portion, a
tether portion, and a retaining means portion.
BACKGROUND
[0003] The manufacture of simple one-piece closures using
polyethylene compositions is well known to persons skilled in the
art.
[0004] Bottle closure systems and designs incorporating an
integrated tethering means, which secures a cap portion to a bottle
after the cap
[0005] has been removed from a bottle opening are also well known.
Such designs typically involve molding processes which present a
more complicated and longer flow path for a chosen plastic material
relative to simple one-piece closure designs. As such, it would be
beneficial to make tethered closure systems using a thermoplastic
material which shows good performance in molding applications,
especially those which involve longer and more tortuous flow paths
in a mold. It would also be advantageous to make a tethered closure
system using a material that has sufficient stress crack resistance
and flexibility, as the tethering portion would need to be both
strong enough to prevent loss of the cap portion once it has been
removed from a bottle opening, and flexible enough to allow the
tethering portion to be formed or bent into suitable closure system
designs.
SUMMARY
[0006] The present disclosure concerns bottle closure assemblies
including a cap portion, a tether portion, and a retaining means
portion. The bottle closure assembly can be made at least in part
from a polyethylene copolymer having good organoleptic
properties.
[0007] An embodiment of the present disclosure provides a bottle
closure assembly which includes a cap portion, a tether portion,
and a retaining means portion, the bottle closure assembly being
made at least in part from a polyethylene copolymer which has a
density of from 0.940 to 0.962 g/cm.sup.3, a melt index 12 of less
than 1.5 g/10 min, an amount of terminal unsaturation of at least
0.45 per 1000 carbon atoms, fewer than 0.9 parts per million of
titanium, and fewer than 0.4 parts per million of chromium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1A shows an embodiment of a bottle closure assembly
fitted to a bottle opening and in a "closed" or "sealed" position.
FIG. 1B shows an embodiment of a bottle closure assembly as a cap
portion is rotated in order to bring about its removal from a
bottle opening. FIG. 1C shows an embodiment of a bottle closure
assembly after a cap portion has been removed from a bottle
opening. FIG. 1C shows how an elongated tether portion connects at
least one point on a cap portion to at least one point on a
retaining collar portion once a cap portion has been removed from a
bottle opening.
[0009] FIG. 2A shows an embodiment of a bottle closure assembly
fitted over a bottle opening and before a cap portion has been
removed from a bottle. FIG. 2B shows an embodiment of a bottle
closure assembly after a cap portion has been removed from a bottle
opening. FIG. 2B also shows how an elongated tether portion
connects at least one point on a cap portion to at least one point
on a retaining collar portion once a cap portion has been removed
from a bottle opening, thereby preventing its loss.
[0010] FIG. 3A shows an embodiment of a bottle closure assembly.
FIG. 3B shows an embodiment of a bottle closure assembly after a
cap portion has been removed from a bottle opening. FIG. 3B also
shows how an elongated tether portion connects at least one point
on a cap portion to at least one point on a retaining collar
portion once a cap portion has been removed from a bottle opening,
thereby preventing its loss. FIG. 3C shows how an elongated tether
portion connects at least one point on a cap portion to at least
one point on a retaining collar portion once a cap portion has been
removed from a bottle opening. FIG. 3C further shows that a bottle
can be a carton, a container, or any other suitable containment
vessel which has or is fitted with an aperture or opening which can
be covered or sealed using a bottle closure assembly.
[0011] FIG. 4A shows an embodiment of a bottle closure assembly in
the absence of a bottle. The bottle closure assembly has a cap
portion, an elongated tether portion, and a retaining collar
portion. FIG. 4B shows an embodiment of a bottle closure assembly
fitted over a bottle opening and before a cap portion has been
removed from a bottle opening. FIG. 4C shows an embodiment of a
bottle closure assembly after a cap portion has been removed from a
bottle opening.
[0012] FIG. 5A shows an embodiment of a bottle closure assembly in
the absence of a bottle. FIG. 5B shows an embodiment of a bottle
closure assembly as a cap portion is rotated in order to bring
about its removal from a bottle opening.
[0013] FIG. 6A shows an embodiment of a bottle closure assembly
which fits over a bottle opening. FIG. 6B show an embodiment of a
bottle closure assembly after a cap portion has been removed from a
bottle opening. FIG. 6B shows how an elongated tether portion
connects at least one point on a cap portion to at least one point
on a retaining collar portion once a cap portion has been removed
from a bottle opening.
[0014] FIG. 7A shows an embodiment of a bottle closure assembly
fitted to a bottle opening and in a "closed" or "sealed" position.
FIG. 7B shows an embodiment of a bottle closure assembly after a
cap portion has been removed from a bottle opening. FIG. 7B shows
how an elongated tether portion connects at least one point on a
cap portion to at least one point on a retaining collar portion
once a cap portion has been removed from a bottle opening.
[0015] FIG. 8 shows a gel permeation chromatograph of the polymer
used in Example 3.
[0016] FIG. 9 shows a gel permeation chromatograph of the polymer
used in Example 4.
[0017] FIG. 10A shows a perspective view of a closure having a
tether proxy. FIG. 10B shows a front elevation view of a closure
having a tether proxy. In FIGS. 10A and 10B a tether proxy connects
a cap portion to a tamper evident band.
[0018] FIG. 11A shows a perspective view of a closure having a
tether proxy after much of the tamper evident band has been
removed. In FIG. 11A a tether proxy connects a cap portion to the
remaining section of the tamper evident band.
[0019] FIG. 11B shows a front elevation partial cross-sectional
schematic view of a closure having a tether proxy and being mounted
on a pre-form for shear deformation testing. Prior to mounting the
closure on the pre-form, much of the tamper evident band was
removed. The tether proxy connects a cap portion to the remaining
section of the tamper evident band. To measure shear deformation of
the tether proxy, the remaining section of the tamper evident band
is clamped in a stationary position to the pre-form, while the cap
portion is rotated within a torque tester, as shown.
[0020] FIG. 11C shows a side elevation partial cross-sectional
schematic view of a closure having a tether proxy and being mounted
on a pre-form for tear deformation testing. The tamper evident band
was deflected down and away from the cap portion, while leaving the
tether proxy intact. The tether proxy connects the cap portion to
the downwardly deflected tamper evident band. To measure tear
deformation of the tether proxy, the downwardly deflected tamper
evident band is clamped in a stationary position to the pre-form,
while the cap portion is rotated within a torque tester, as
shown.
[0021] FIGS. 12A and 12B show a perspective view and a front
elevation view respectively, of a tether proxy after much of the
cap portion and much of the tamper evident band have been removed.
To measure tensile deformation of the tether proxy, the remaining
section of the cap portion and the remaining section of the tamper
evident band are each clamped and then drawn apart in a vertical
direction, within a tensile tester, as shown.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0022] Any suitable bottle closure assembly design including a cap
portion or a closure portion, a tether portion, and a retaining
means portion is contemplated for use in the present disclosure, so
long as it is made at least in part using a polyethylene copolymer
as described herein. However, some specific non-limiting examples
of suitable bottle closure assemblies for use in the present
disclosure are disclosed in U.S. Pat. Nos. 3,904,062; 4,474,302;
4,557,393; 4,564,114; 4,573,602; 4,583,652; 4,805,792; 5,725,115;
8,443,994; 8,720,716; 9,493,283; and 9,776,779; U.S. Patent
Application Publication Nos. 2004/0016715 and 2008/0197135; U.S.
Design Pat. No. D593,856; and WO 2015/061834; all of which are
incorporated herein by reference. For further reference, some
bottle closure assembly designs which may be used in embodiments of
the present disclosure are shown in FIGS. 1-7.
[0023] An embodiment of the disclosure is a bottle closure assembly
including: a cap portion, a tether portion, and a retaining means
portion, the cap portion being molded to reversibly engage and
cover a bottle opening, the retaining means portion being molded to
irreversibly engage a bottle neck or an upper portion of a bottle,
and where the tether portion connects at least one point on the cap
portion to at least one point on the retaining means portion,
wherein the cap portion, optionally the tether portion, and
optionally the retaining means portion are made from a polyethylene
copolymer which has a density of from 0.940 to 0.962 g/cm.sup.3, a
melt index 12 of less than 1.5 g/10 min, an amount of terminal
unsaturation of at least 0.45 per 1000 carbon atoms, fewer than 0.9
parts per million of titanium, and fewer than 0.4 parts per million
of chromium.
[0024] An embodiment of the disclosure is a bottle closure assembly
including: a cap portion, an elongated tether portion, and a
retaining means portion, the cap portion being molded to reversibly
engage and cover a bottle opening, the retaining means portion
being molded to irreversibly engage a bottle neck or an upper
portion of a bottle, and the elongated tether portion being molded
to connect at least one point on the cap portion to at least one
point on the retaining means portion, wherein the cap portion,
optionally the elongated tether portion, and optionally the
retaining means portion are made from a polyethylene copolymer
which has a density of from 0.940 to 0.962 g/cm.sup.3, a melt index
12 of less than 1.5 g/10 min, an amount of terminal unsaturation of
at least 0.45 per 1000 carbon atoms, fewer than 0.9 parts per
million of titanium, and fewer than 0.4 parts per million of
chromium.
[0025] An embodiment of the disclosure is a bottle closure assembly
including an integrally molded: cap portion, tether portion, and
retaining means portion; the cap portion being molded to reversibly
engage and cover a bottle opening, the retaining means portion
being molded to irreversibly engage a bottle neck or an upper
portion of a bottle, and the tether portion being molded to connect
at least one point on the cap portion to at least one point on the
retaining means portion; wherein the integrally molded: cap
portion, tether portion, and retaining means portion are made from
a polyethylene copolymer which has a density of from 0.940 to 0.962
g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an amount of
terminal unsaturation of at least 0.45 per 1000 carbon atoms, fewer
than 0.9 parts per million of titanium, and fewer than 0.4 parts
per million of chromium.
[0026] An embodiment of the disclosure is a bottle closure assembly
including an integrally molded: cap portion, elongated tether
portion, and retaining means portion; the cap portion being molded
to reversibly engage and cover a bottle opening, the retaining
means portion being molded to irreversibly engage a bottle neck or
an upper portion of a bottle, and the elongated tether portion
being molded to connect at least one point on the cap portion to at
least one point on the retaining means portion; wherein the
integrally molded: cap portion, elongated tether portion, and
retaining means portion are made from a polyethylene copolymer
which has a density of from 0.940 to 0.962 g/cm.sup.3, a melt index
12 of less than 1.5 g/10 min, an amount of terminal unsaturation of
at least 0.45 per 1000 carbon atoms, fewer than 0.9 parts per
million of titanium, and fewer than 0.4 parts per million of
chromium.
[0027] An embodiment of the disclosure is a bottle closure assembly
including an integrally molded: cap portion, elongated tether
portion, and retaining collar portion; the cap portion being molded
to reversibly engage and cover a bottle opening, the retaining
collar portion being molded to irreversibly engage a bottle neck or
an upper portion of a bottle, and the elongated tether portion
being molded to connect at least one point on the cap portion to at
least one point on the retaining collar portion; wherein the
integrally molded: cap portion, elongated tether portion, and
retaining collar portion are made from a polyethylene copolymer
which has a density of from 0.940 to 0.962 g/cm.sup.3, a melt index
12 of less than 1.5 g/10 min, an amount of terminal unsaturation of
at least 0.45 per 1000 carbon atoms, fewer than 0.9 parts per
million of titanium, and fewer than 0.4 parts per million of
chromium.
[0028] An embodiment of the disclosure is a bottle closure assembly
including: a cap portion, an elongated tether portion, and a
retaining collar portion, the cap portion being molded to
reversibly engage and cover a bottle opening, the retaining collar
portion being molded to irreversibly engage a bottle neck or an
upper portion of a bottle, the elongated tether portion including a
tether strip which is frangibly connected along a portion of its
upper edge to a descending annular edge of the cap portion and
which is frangibly connected along a portion of its lower edge to
an upper annular edge of the retaining collar portion, the tether
strip being integrally formed with and connected at one end to at
least one point on the cap portion and integrally formed with and
connected at another end to at least one point on the retaining
collar portion, the frangible sections being breakable when the cap
portion is removed from a bottle opening, but where the cap portion
remains connected to the retaining collar portion via the tether
strip; wherein the cap portion, the elongated tether portion, and
the retaining collar portion are integrally molded from a
polyethylene copolymer which has a density of from 0.940 to 0.962
g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an amount of
terminal unsaturation of at least 0.45 per 1000 carbon atoms, fewer
than 0.9 parts per million of titanium, and fewer than 0.4 parts
per million of chromium.
[0029] An embodiment of the disclosure is a bottle closure assembly
including: a cap portion, an elongated tether portion, and a
retaining collar portion, the cap portion being molded to
reversibly engage and cover a bottle opening, the elongated tether
portion including a tether strip which is frangibly connected along
a portion of its upper edge to a descending annular edge of the cap
portion and which is frangibly connected along a portion of its
lower edge to an upper annular edge of the retaining collar
portion, the tether strip being integrally formed with and
connected at one end to at least one point on the cap portion and
integrally formed with and connected at another end to at least one
point on the retaining collar portion, the frangible sections being
breakable when the cap portion is removed from a bottle opening,
but where the cap portion remains connected to the retaining collar
via the tether strip; wherein the cap portion, the elongated tether
portion, and the retaining collar portion are integrally molded
from a polyethylene copolymer which has a density of from 0.940 to
0.962 g/cm.sup.3, a melt index 12 of less than 1.5 g/10 min, an
amount of terminal unsaturation of at least 0.45 per 1000 carbon
atoms, fewer than 0.9 parts per million of titanium, and fewer than
0.4 parts per million of chromium.
[0030] When integrally molded, the bottle closure assembly presents
long flow paths for a plastic material to fill during
manufacturing. In the present disclosure, the term "integrally
molded" means that that components referred to are molded in a
single continuous mold.
[0031] In some embodiments, the cap portion is molded to reversibly
engage and cover a bottle opening or aperture from which a liquid
or other type of foodstuffs can be dispensed and so is removable
therefrom.
[0032] In some embodiments, the retaining means portion, which in
some embodiments may be a retaining collar portion, is generally
not to be removed, or is not easily removable from a bottle and in
some embodiments, the retaining collar engages a bottle neck, or an
upper portion of a bottle.
[0033] In some embodiments, the tether portion, which in some
embodiments may be an elongated tether portion, connects at least
one point of the cap portion to at least one point on the retaining
means portion, so that when the cap portion is removed from a
bottle opening, the cap portion remains flexibly fixed to the
bottle via the tether portion, and the retaining means portion.
[0034] In the present disclosure, the terms "bottle", "container",
"jar", "carton", "pouch", "package", and the like may be used
interchangeably. That is, a "bottle closure assembly" may also be
considered a "container closure assembly", a "jar close assembly",
a "carton closure assembly", a "pouch closure assembly", a "package
closure assembly", and the like. A person skilled in the art will
understand that a "bottle closure assembly" as described in the
present disclosure can be used to close or seal a number of
different types of structural containers having different designs
and contours.
[0035] The terms "cap", "closure", "closure portion", "cap
portion", and the like, are used in the present disclosure to
connote any suitably shaped molded article for enclosing, sealing,
closing or covering etc., a suitably shaped opening, a suitably
molded aperture, an open necked structure, or the like used in
combination with a container, a bottle, a jar, and the like.
[0036] In an embodiment of the disclosure, the retaining means
portion can reversibly or irreversible engage a bottle neck, a
shoulder section of a bottle, or an upper portion of a bottle, or a
fitment (e.g., a fitment on a pouch or a carton).
[0037] In an embodiment of the disclosure, the retaining means
portion can also serve as a tamper evident band (TEB).
[0038] In the present disclosure, the term "bottle neck" should be
construed to mean a bottle neck per se but also any sort of similar
or functionally equivalent structure such as a spout, a spigot, a
fitment, or the like.
[0039] In an embodiment of the disclosure, the retaining means
portion is molded or shaped to reversibly or irreversible engage a
bottle neck, a shoulder section of a bottle, or an upper portion of
a bottle.
[0040] In an embodiment of the disclosure, the retaining means
portion is a retaining collar portion which reversibly or
irreversibly engages a bottle neck, a shoulder section of a bottle,
or an upper portion of a bottle.
[0041] In an embodiment of the disclosure, the retaining collar
portion is circularly or annularly shaped so as to reversibly or
irreversibly engage a bottle neck, a shoulder section of a bottle,
or an upper portion of a bottle.
[0042] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
means portion where the cap portion, the tether portion, and the
retaining means portion are all integrally molded in one piece.
[0043] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
collar portion where the cap portion, the tether portion, and the
retaining collar portion are all integrally molded in one
piece.
[0044] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining means portion where the cap portion, the elongated tether
portion, and the retaining means portion are all integrally molded
in one piece.
[0045] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining collar portion where the cap portion, the elongated
tether portion, and the retaining collar portion are all integrally
molded in one piece.
[0046] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
means portion where the cap portion, the tether portion, and the
retaining means portion are separately molded.
[0047] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
collar portion where the cap portion, the tether portion, and the
retaining collar portion are separately molded.
[0048] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining means portion where the cap portion, the elongated tether
portion, and the retaining means portion are separately molded.
[0049] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining collar portion where the cap portion, the elongated
tether portion, and the retaining collar portion are separately
molded.
[0050] In embodiments of the disclosure, when separately molded the
cap portion, the tether portion, and the retaining means portion
may be fixed together using any means known in the art. For
example, the cap portion, the tether portion, and the retaining
means portion may be glued together, or welded together using
applied heat, sonication, or other methods known in the art for
fusing plastic materials together.
[0051] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
means portion where the cap portion, the tether portion, and the
retaining means portion are made from the same or different
materials.
[0052] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, a tether portion, and a retaining
collar portion where the cap portion, the tether portion, and the
retaining collar portion are made from the same or different
materials.
[0053] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining means portion where the cap portion, the elongated tether
portion, and the retaining means portion are made from the same or
different materials.
[0054] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion, an elongated tether portion, and a
retaining collar portion where the cap portion, the elongated
tether portion, and the retaining collar portion are made from the
same or different materials.
[0055] In an embodiment of the present disclosure, the "tether
portion" is of sufficient length and/or has a design which allows
removal of a "cap portion" from a bottle opening while at the same
time preventing the loss of the cap portion by maintaining a
connection between the cap portion and a bottle, container, or the
like by forming a connection between at least one point on the cap
portion and at least one point on a "retaining means portion".
[0056] In an embodiment of the present disclosure, the tether
portion may be an "elongated tether portion", where "elongated"
means that the tether portion will have at least one dimension
(length) which is larger than at least one other dimension (width
or height/thickness) or vice versa. Or considered another way,
"elongated" means that the tether has a length which is greater
than its width and/or height/thickness.
[0057] In an embodiment of the present disclosure, the tether
portion will have dimensions (e.g., width and/or height/thickness)
which offer sufficient strength to prevent facile cleavage or
breakage of the tether when placed under stress or duress, such as
for example when the tether is subjected to bending or flexional
forces. For example, in an embodiment of the disclosure, the tether
will have sufficient width and/or height/thickness so as to prevent
facile breakage of the tether when masticated.
[0058] In an embodiment of the present disclosure, the "elongated
tether portion" is of sufficient length and/or has a design which
allows removal of a "cap portion" from a bottle opening while at
the same time preventing the loss of the cap portion by maintaining
a connection between the cap portion and a bottle, container, or
the like by forming a connection between at least one point on the
cap portion and at least one point on a "retaining means
portion".
[0059] In embodiments of the disclosure, the retaining means
portion may be a "retaining collar portion" which engages some
portion of a bottle neck or an upper portion of a bottle,
container, or the like.
[0060] In embodiments of the disclosure, the retaining means
portion may be a "retaining collar portion" which irreversibly
engages some portion of a bottle neck, a spout, a spigot, a fitment
on a pouch, or the like.
[0061] Alternatively, the retaining means portion may be a
"retaining collar portion" which engages a bottle neck, or an upper
portion of a bottle, container, or the like.
[0062] In an embodiment of the disclosure, the retaining collar
portion may rotatably engage a bottle neck, or upper portion of a
bottle, container, or the like.
[0063] In an embodiment of the disclosure, the retaining means
portion is a retaining collar portion which is molded to
irreversibly engage a bottle neck or an upper portion of a bottle,
container, or the like.
[0064] In an embodiment of the disclosure, the retaining collar
portion is annularly shaped or circularly shaped and can fit over
and engage a bottle neck or an upper portion of a bottle,
container, or the like.
[0065] The cap portion may be a single contiguous piece, or it may
itself include one or more cap portion structures.
[0066] The tether portion in the present disclosure need not serve
as a hinged connection between a cap portion and a retaining means
portion (such as for example a retaining collar portion), and the
tether portion need not include a hinged portion or area, but the
tether portion may in some embodiments of the disclosure include a
hinge and when present the hinge may be a so called "living
hinge".
[0067] In an embodiment of the disclosure, the elongated tether
portion has a length which is sufficient to allow the cap portion
of the bottle closure assembly to swing or hang out of the way of a
bottle opening, aperture, or the like so as not to interfere with
the dispensation of the bottle contents, while at the same time
tethering the cap portion to a bottle via the retaining means
portion.
[0068] The cap portion may itself be a screw cap which threadingly
engages a threaded system on a bottle neck, spigot, spout, valve,
fitment on a pouch, or the like. The cap portion may alternatively
be a snap cap which reversibly engages a bottle neck, spigot,
spout, or the like. The cap portion may also reversibly engage a
retaining collar portion in a snap fitting or in a complementary
arrangement of threaded structures. The cap portion may include a
first cap portion and a second cap portion, where the first cap
portion engages the second cap portion in a snap fitting, and the
second cap portion engages a bottle neck, or upper portion of a
bottle in a reversible or irreversible manner. For example, a
second cap portion may have a threaded structure which threadingly
engages a threaded system on a bottle neck. Alternatively, the
second cap portion may itself engage a bottle neck by any suitable
type of snap fitting. The cap portion may also include more than
two cap portions.
[0069] In an embodiment of the disclosure, the bottle closure
assembly includes a cap portion adapted to close an opening in a
bottle or the like by making a frictional engagement with the
opening.
[0070] In an embodiment of the disclosure, the cap portion has
internal threads which mate with external threads surrounding an
opening in a bottle, such as on a bottle neck, spigot, or spout for
example.
[0071] In an embodiment of the disclosure, the retaining collar
portion is adapted to cooperate with a shoulder or a flange on the
neck of a bottle or an upper portion of a bottle which is to be
sealed by the cap portion.
[0072] In an embodiment of the disclosure, the retaining collar
portion is annularly or cylindrically shaped and fits onto the neck
of a bottle and is coupled to the same, using any suitable coupling
means, such as a snap fitting, or a threaded engagement. In an
embodiment, the retaining collar portion is molded to snap fit onto
a bottle neck, bottle aperture, spigot, spout, or the like. In an
embodiment, the retaining collar portion may be threaded onto a
bottle neck, bottle aperture, spigot, spout, or the like. In an
embodiment the retaining collar portion may itself have an internal
threading system which mates with external threads on a bottle
neck, bottle aperture, spigot, spout, or the like. In an
embodiment, the retaining collar portion is dimensioned to be
engaged beneath a flange or shoulder molded into a bottle neck or
an upper portion of a bottle. For example, the retaining collar
portion may have an annular radial dimension which prevents it from
moving past an annular shoulder integrally molded into a bottle
neck or into an upper portion of a bottle. In this case the annular
outwardly extending shoulder on a bottle neck or on an upper
portion of a bottle acts as a camming surface which prevents
movement of the retaining collar toward a bottle opening. Such a
shoulder on a bottle could for example have a tapered outer annular
edge which allows the retaining collar portion to be slipped onto
the bottle in an irreversible manner. In an embodiment of the
disclosure, there may be outwardly extending annularly spaced
bosses or the like on a bottle neck or an upper portion of a
bottle, against which the retaining collar abuts to hold it on to a
bottle neck, bottle aperture, spigot, spout, or the like. Persons
skilled in the art will appreciate that other means could be used
to secure the retaining collar portion to a bottle neck, the upper
portion of a bottle, a spout, spigot, and the like.
[0073] In an embodiment of the disclosure, the elongated tether
portion includes a connecting strip having a first end connected to
a least one point of the closure portion and a second end connected
to at least one point of the retaining collar portion, a lower edge
and an upper edge, wherein when the cap portion is fitted on to a
bottle opening, the connecting strip at least partially encircles a
bottle neck, spout, or the like between the cap portion and the
retaining collar portion, and where at least a portion of the upper
edge of the connecting strip is frangibly connected to a lower edge
of the cap portion, and where at least a portion of the lower edge
of the connecting strip is frangibly connected to an upper edge of
the retaining collar portion, and where when the cap portion is
removed from a bottle opening by breaking the frangible connections
between the cap portion, the connecting strip and the retaining
collar portion, the cap portion remains secured to retaining collar
portion and the bottle via the connecting strip.
[0074] In an embodiment, the elongated tether portion is a
cylindrically adapted connecting strip which at least partially
encircles a bottle neck, spout, or the like and is located between
the cap portion and the retaining collar portion prior to removal
of the cap portion form a bottle opening.
[0075] In an embodiment, the elongated tether portion has a first
end which is connected to at least one point on the cap portion and
a second end which is connected to at least one point on the
retaining collar portion.
[0076] In an embodiment, the cap portion, the elongated tether
portion, and the retaining collar portion are integrally molded so
that the elongated tether portion has a first end which is
connected to at least one point on the cap portion and a second end
which is connected to at least one point on the retaining
collar.
[0077] In an embodiment, the cap portion, the elongated tether
portion, and the retaining collar portion are integrally molded so
that the elongated tether portion has a first end which is
connected to at least one point on the cap portion and a second end
which is connected to at least one point on the retaining collar
portion, and wherein the elongated tether portion has an upper edge
and a lower edge, where at least a portion of the upper edge is
frangibly connected to a lower edge of the cap portion, and at
least a portion of the lower edge is frangibly connected to an
upper edge of the retaining collar portion, the frangibly connected
portions being breakable when the closure is removed from a bottle
opening.
[0078] In an embodiment of the disclosure, the frangible
connections or frangibly connected portions are regularly or
irregularly spaced molded sections (e.g., pins) having a dimension
suitably small to allow facile breakage.
[0079] Frangible connections or frangibly connected portions can
also be thought of as defining a weakening line along which the
elongated tethering portion can be separated from the cap portion
and the retaining collar portion. Such weakening lines can be
generally defined as open sections alternating with bridging
sections, where the bridging sections have a dimension suitably
small to allow facile breakage. Alternatively, the weakening lines
are defined by lines of plastic which have been made thin enough to
break under stress.
[0080] In an embodiment of the disclosure, a single piece of a
molded plastic having a suitable shape, is purposely weakened (by
for example, regular or irregularly spaced cuts) along
predetermined lines to define a cap portion, an elongated tether
portion, and a retaining collar portion, wherein the cap portion is
shaped to reversibly engage and cover a bottle opening, the
retaining means portion is shaped to irreversibly engage a bottle
neck or an upper portion of a bottle, and where the elongated
tether portion connects at least one point on the cap portion to at
least one point on the retaining means portion.
[0081] In an embodiment of the disclosure, the bottle closure
assembly includes an upper cap portion, an intermediate elongate
tethering portion, and a lower retaining collar portion, where the
intermediate elongate tethering portion has a first end permanently
connected to at least one point of the upper cap portion and a
second end permanently connected to at least one point on the lower
retaining collar portion, wherein the intermediate elongate
tethering portion is partially joined to a lower annular edge of
the upper cap portion along a first peripheral weakening line and
the intermediate elongate tethering portion is partially joined to
an upper annular edge of the lower retaining collar portion along a
second peripheral weakening line, wherein removal of the upper cap
portion from a bottle separates the upper cap portion from the
intermediate elongate tethering portion along the first peripheral
weakening line and separates the lower retaining collar portion
from the intermediate elongate tethering portion along the second
weakening line, while maintaining a linkage between the upper cap
portion and the lower retaining collar portion through the
intermediate elongate tethering portion.
[0082] In an embodiment of the disclosure, and with reference to
FIGS. 1A-1C, the bottle closure assembly includes: an upper cap
portion, 1 dimensioned to reversibly cover and close a bottle
opening, a lower retaining collar portion, 10 dimensioned to
irreversibly engage a bottle neck, or an upper portion of a bottle,
and an elongated tether portion, 5 being dimensioned as a strip
which at least partially encircles a bottle neck between the upper
cap portion and the lower retaining collar portion, the strip
including a first end, a second end, an upper edge and a lower
edge, the upper edge of which is in part contiguous with the upper
cap portion, the lower edge of which is in part contiguous with the
lower retaining collar portion, whereby removal of the upper cap
portion from a bottle (by for example rotation about a threaded
system on the bottle neck) separates the elongated tether portion
from the upper cap portion and the lower retaining collar portion,
while at the same leaving the upper cap portion attached to the
lower retaining collar via the elongated tether portion.
[0083] In an embodiment of the disclosure, and with reference to
FIGS. 2A and 2B, the bottle closure assembly includes: an upper cap
portion, 1 dimensioned to reversibly cover and close a bottle
opening, 2 a lower retaining collar portion, 10 dimensioned to
irreversibly engage a bottle neck, 3 or an upper portion of a
bottle, and an elongated tether portion, 5 being dimensioned as a
strip which at least partially encircles a bottle neck between the
upper cap portion and the lower retaining collar portion, the strip
including a first end, 6 a second end, 7 an upper edge, 11 and a
lower edge, 12, the upper edge of which is in part frangibly
attached, 8 to the upper cap portion, and in part contiguous with
the upper cap portion, the lower edge of which is in part frangibly
attached, 9 to the lower retaining collar portion and in part
contiguous with the lower retaining collar portion, whereby removal
of the upper cap portion from a bottle will rupture the frangible
attachments while leaving the upper cap portion attached to the
lower retaining collar portion via the elongated tether portion. In
an embodiment and with reference to FIG. 2B, the bottle opening may
have peripheral threads, 15 which engage threads on the inside of
the cap portion.
[0084] In an embodiment of the disclosure, and with reference to
FIGS. 3A-3C, the bottle closure assembly includes: an upper cap
portion, 1 dimensioned to reversibly cover and close a bottle
opening, 2, a lower retaining collar portion, 10 dimensioned to
irreversibly engage a bottle neck, 3 or an upper portion of a
bottle, and an elongated tether portion, 5 being dimensioned as a
strip which at least partially encircles a bottle neck between the
upper cap portion and the lower retaining collar portion, the strip
having a first end, 6 a second end, 7 an upper edge, and a lower
edge, the upper edge of which is in part frangibly attached to the
upper cap portion by frangible elements, 20 (such as for example
breakable pins), and in part contiguous with the upper cap portion,
the lower edge of which is in part frangibly attached to the lower
retaining collar portion by frangible elements, 20 (such as for
example breakable pins) and in part contiguous with the lower
retaining collar portion, whereby removal of the upper cap portion
from a bottle opening will rupture the frangible attachments while
leaving the upper cap portion attached to the lower retaining
collar portion via the elongated tether portion, 5. In an
embodiment and with reference to FIG. 3B, the bottle neck and
opening may have peripheral threads, 15 which engage threads on the
inside of the cap portion.
[0085] In an embodiment of the disclosure, and with reference to
FIGS. 4A-4C, the bottle closure assembly includes a cap portion, 1,
an elongated tether portion, 5, and a retaining collar portion,
10.
[0086] In an embodiment of the disclosure, and with reference to
FIGS. 5A and 5B, the bottle closure assembly includes: a cap
portion, 1 a tether portion, 5 and a retaining means portion, 10
the cap portion being molded to reversibly engage and cover a
bottle opening, the retaining means portion being molded to
irreversibly engage a bottle neck or an upper portion of a bottle,
18 and the tether portion being molded to connect at least one
point on the cap portion to at least one point on the retaining
means portion, the cap portion and the retaining collar portion
extending coaxially with each other, the tether portion including a
tabbed tether strip which is integrally formed with and secured at
its respective ends (6 and 7) to the cap portion and the retaining
collar portion, the tether strip being joined to the cap portion
and the retaining collar along a preselected length of the tether
strip to be manually separated from the cap portion and the
retaining collar portion by frangible elements, 20 of a preselected
thickness to permit the elongated tether strip to be manually
separated from the cap portion and the retaining collar portion
along the pre-selected length, the tether strip being of such
length so as to permit the cap portion to be removed from a bottle
opening while at the same remaining attached to the bottle via the
tether strip and the retaining collar. In an embodiment and as
shown in FIG. 5B, a cap portion may have a circular top wall, 16
and a descending annular side wall 17.
[0087] In an embodiment of the disclosure, the bottle closure
assembly includes: a cap portion having a top wall and a side wall,
an elongated tether portion, and a retaining collar portion, the
cap portion being molded to reversibly engage and cover a bottle
opening, the retaining collar portion being annular and being
molded to irreversibly engage a ridge or flange on a bottle neck or
on an upper portion of a bottle, and the elongated tether portion
being integrally molded with the cap portion and the retaining
collar portion to connect at least one point on the cap side wall
to at least one point on the retaining collar portion, wherein the
elongated tether portion runs between the cap side wall and the
retaining collar portion along the circumference of the cap portion
when the cap portion is on a bottle and the elongated tether
portion connects at least one point on the cap side wall to at
least one point on the retaining collar portion when the cap
portion is removed from a bottle.
[0088] In an embodiment of the disclosure, and with reference to
FIGS. 6A and 6B, the bottle closure assembly includes an upper cap
portion, 1, an opening, 2, an intermediate elongate tethering
portion, 5 and a lower retaining collar portion, 10 where the
intermediate elongate tethering portion has a first end permanently
connected to at least one point of the upper cap portion and a
second end permanently connected to at least one point on the lower
retaining collar portion, wherein the intermediate elongate
tethering portion is partially joined to a lower annular edge of
the upper cap portion along a first peripheral weakening line
defined by perforations, 25 and the intermediate elongate tethering
portion is partially joined to an upper annular edge of said lower
retaining collar portion along a second peripheral weakening line
defined by perforations, 25 wherein removal of the upper cap
portion from a bottle separates the upper cap portion from the
tethering portion along the first peripheral weakening line and
separates the lower retaining collar portion from the tethering
portion along the second weakening line, while maintaining a
linkage between the upper cap portion and the lower retaining
collar portion through the intermediate elongated tethering
portion.
[0089] In an embodiment of the disclosure, and with reference to
FIGS. 6A and 6B, a bottle neck 3, may have an annular groove 28,
which presents a flange onto which the cap portion, 1 may
reversibly engage in a snap fit arrangement. In an embodiment and
with reference to FIGS. 6A and 6B a bottle neck may have an
outwardly extended annular flange, 29 which prevents a retaining
collar portion, 10 from being removed from a bottle neck.
[0090] In an embodiment of the disclosure, and with reference to
FIGS. 7A and 7B, the bottle closure assembly includes a cap
portion, 1, an elongated tether portion, 5, and a retaining collar
portion, 10. The elongated tether portion connects at least one
point of the cap portion at a first end, 6 to at least one point of
the retaining collar portion at a second end, 7. The elongated
tether portion may be further joined to the cap portion along a
frangible connection 8. The elongated tether portion may be further
joined to the retaining collar portion along a frangible connection
9. Separation of the cap portion from the elongated tether portion
along a frangible connection 8 along with separation of the
retaining collar portion from the elongated tether portion along a
frangible connection 9, allows removal of the cap portion from a
bottle opening while at the same time securing it to the bottle via
the elongated tether portion, and the retaining collar portion.
[0091] In an embodiment of the disclosure, the bottle closure
assembly includes: a cap portion, the cap portion being dimensioned
to cover and close a bottle opening, a retaining collar portion,
and an elongated tether portion which forms an elastic connection
between at least one point on the cap portion and at least one
point on the retaining collar portion.
[0092] In an embodiment of the disclosure, the retaining means
portion is integrally molded into a bottle, container, or the
like.
[0093] In an embodiment of the disclosure, the retaining collar
portion is integrally molded into a bottle, container, or the
like.
[0094] In an embodiment of the disclosure, the tether portion fixes
the cap portion to the retaining collar portion which remains
secured to the bottle, making it difficult to separate the cap
portion from the bottle, thereby preventing its loss, while at the
same time allowing rotation of the cap portion for facile removal
and replacement of the same from and onto a bottle opening.
[0095] In an embodiment of the present disclosure, the bottle
closure assembly is made in part or in full using a polyethylene
copolymer which has a density of from 0.940 to 0.962 g/cm.sup.3, a
melt index 12 of less than 1.5 g/10 min, an amount of terminal
unsaturation of at least 0.45 per 1000 carbon atoms, fewer than 0.9
parts per million of titanium, and fewer than 0.4 parts per million
of chromium.
[0096] In an embodiment of the disclosure, the cap portion,
optionally the tether portion, and optionally the retaining collar
portion are made from a polyethylene copolymer which has a density
of from 0.940 to 0.962 g/cm.sup.3, a melt index 12 of less than 1.5
g/10 min, an amount of terminal unsaturation of at least 0.45 per
1000 carbon atoms, fewer than 0.9 parts per million of titanium,
and fewer than 0.4 parts per million of chromium.
[0097] In an embodiment of the disclosure, the cap portion, the
tether portion, and the retaining collar portion are all integrally
molded from a polyethylene copolymer which has a density of from
0.940 to 0.962 g/cm.sup.3, a melt index 12 of less than 1.5 g/10
min, an amount of terminal unsaturation of at least 0.45 per 1000
carbon atoms, fewer than 0.9 parts per million of titanium, and
fewer than 0.4 parts per million of chromium.
[0098] Suitable polyethylene copolymers for use in the manufacture
of part or all of the bottle closure assembly are described in more
detail below.
[0099] As used herein, the term "homopolymer" is meant to convey
its conventional meaning, that the polymer is prepared using only
ethylene as a deliberately added polymerizable monomer.
[0100] By the term "ethylene copolymer" or "polyethylene
copolymer", it is meant that the product polymer is the product of
a polymerization process, where ethylene and one or more than one
comonomer were deliberately added or was deliberately present as
polymerizable olefins.
The Polyethylene Copolymer
[0101] In an embodiment of the present disclosure, the polyethylene
copolymer has a density of from 0.940 to 0.962 g/cm.sup.3 or falls
within any narrower range within this range, or is any number
within this range. For example, in further embodiments of the
present disclosure the polyethylene copolymer has a density of from
0.945 to 0.960 g/cm.sup.3, from 0.947 to 0.960 g/cm.sup.3, or from
0.947 to 0.959 g/cm.sup.3, or from 0.949 to 0.959 g/cm.sup.3
[0102] In an embodiment of the disclosure, the polyethylene
copolymer has a melt index, 12 as determined according to ASTM
D1238 (2.16 kg/190.degree. C.) of less than about 1.5 g/10 min, or
less than 1.25 g/10 min, or less than about 1.0 g/10 min, or less
than 0.75 g/10 min, or less than about 0.5 g/10 min. In further
embodiments of the disclosure, the polyethylene copolymer has a
melt index, 12 as determined according to ASTM D1238 (2.16
kg/190.degree. C.) of from 0.01 to 1.5 g/10 min, or from about 0.1
to about 1.5 g/10 min, or from about 0.1 to about 1.25 g/10 min, or
from about 0.1 to about 1.0 g/10 min, or from about 0.1 to about
0.8 g/10 min, or from 0.2 to about 1.0 g/10 min, or from about 0.2
to about 0.8 g/10 min.
[0103] In an embodiment of the present disclosure, the polyethylene
copolymer has a unimodal profile in a gel permeation chromatograph
obtained according to the method of ASTM D6474-99. In an embodiment
of the present disclosure, the polyethylene copolymer has a bimodal
profile in a gel permeation chromatograph obtained according to the
method of ASTM D6474-99. In an embodiment of the present
disclosure, the polyethylene copolymer has a multimodal profile in
a gel permeation chromatograph obtained according to the method of
ASTM D6474-99.
[0104] The term "unimodal", as used herein, means there will be
only one significant peak or maximum evident in the GPC-curve. A
unimodal profile includes a broad unimodal profile. Alternatively,
the term "unimodal" connotes the presence of a single maxima in a
molecular weight distribution curve generated according to the
method of ASTM D6474-99. In contrast, by the term "bimodal" it is
meant that there will be a secondary peak or shoulder evident in a
GPC-curve which represents a higher or lower molecular weight
component (i.e. the molecular weight distribution, can be said to
have two maxima in a molecular weight distribution curve).
Alternatively, the term "bimodal" connotes the presence of two
maxima in a molecular weight distribution curve generated according
to the method of ASTM D6474-99. The term "multi-modal" denotes the
presence of two or more maxima, including peaks or shoulders in a
molecular weight distribution curve generated according to the
method of ASTM D6474-99.
[0105] In an embodiment of the present disclosure, the polyethylene
copolymer is a polyethylene copolymer having a conventional or
normal comonomer distribution. By the term "normal comonomer
distribution" it is meant that the proportion of comonomer (and
hence side chain branching) decreases with increasing molecular
weight. Such a normal comonomer distribution can be measured using
well known methods such as for example gel permeation
chromatography with Fourier Transform Infra-Red detection.
[0106] In an embodiment of the disclosure, the polyethylene
copolymer is neither a post reactor melt blend nor a post reactor
dry blend. That is, in an embodiment of the disclosure, the
polyethylene copolymer is not the product of melt blending or dry
blending two different polymer compositions outside of a
polymerization reactor.
[0107] In an embodiment of the disclosure, the polyethylene
copolymer is not a blend of two or more different polymer
compositions made in one or more than one polymerization reactor
using two or more different polymerization catalysts.
[0108] In an embodiment of the present disclosure, the polyethylene
copolymer has an ESCR Condition B (10% IGEPAL.RTM. CO-630) of at
least about 1 hour.
[0109] IGEPAL.RTM. CO-630 is a polyoxyethylene (9) nonylphenylether
which has an average M.sub.n of 617 and the structure below and is
available from SIGMA-ALDRICH.RTM..
##STR00001##
[0110] In an embodiment of the present disclosure, the polyethylene
copolymer has an ESCR Condition B (10% IGEPAL.RTM. CO-630) of from
at least about 10 hours (hrs).
[0111] In an embodiment of the present disclosure, the polyethylene
copolymer has an ESCR Condition B (10% IGEPAL.RTM. CO-630) of from
at least about 20 hours.
[0112] In an embodiment of the present disclosure, the polyethylene
copolymer has an ESCR Condition B (10% IGEPAL.RTM. CO-630) of from
about 1 to about 100 hours.
[0113] In an embodiment of the present disclosure, the polyethylene
copolymer has an ESCR Condition B (10% IGEPAL.RTM. CO-630) of from
about 10 to about 100 hours. In an embodiment of the present
disclosure, the polyethylene copolymer has an ESCR Condition B (10%
IGEPAL.RTM. CO-630) of from about 10 to about 75 hours.
[0114] In an embodiment of the disclosure, the polyethylene
copolymer has a weight average molecular weight (M.sub.w) from
about 90,000 to about 300,000 (g/mol). In other embodiments of the
disclosure the polyethylene copolymer has a weight average
molecular weight (M.sub.w) from about 90,000, to about 250,000, or
from about 90,000 to about 225,000, or from about 90,000 to about
200,000, or from about 100,000 to about 300,000, or from about
100,000 to about 250,000, or from about 110,000 to about 225,000,
or from about 125,000 to about 200,000, or from about 125,000 to
about 190,000.
[0115] In an embodiment of the disclosure, the polyethylene
copolymer has a molecular weight distribution (M.sub.w/M.sub.n) of
from about 5.0 to about 16.0. In further embodiments of the
disclosure, the polyethylene copolymer has a molecular weight
distribution (M.sub.w/M.sub.n) of from about 6.0 to about 15.0, or
from about 6.5 to about 14.0, or from about 6.5 to about 13.5.
[0116] In an embodiment of the disclosure, the polyethylene
copolymer has an amount of terminal unsaturation of at least 0.35
per 1000 carbons (or per carbon atom), or at least 0.40 per 1000
carbons, or at least 0.45 per 1000 carbons, or greater than 0.45
per 1000 carbons, or at least 0.50 per 1000 carbons, or greater
than 0.50 per 1000 carbons, or at least 0.55 per 1000 carbons, or
greater than 0.55 per thousand carbons, or at least 0.60 per 1000
carbons, or greater than 0.60 per 1000 carbons, or at least 0.65
per 1000 carbons, or greater than 0.65 per 1000 carbons, or at
least 0.70 per 1000 carbons, or greater than 0.70 per thousand
carbons.
[0117] In an embodiment of the disclosure, the polyethylene
copolymer has a total amount of unsaturation (which includes
internal, side chain, and terminal unsaturation) of at least 0.40
per 1000 carbons (or per carbon atom), or at least 0.45 per 1000
carbons, or at least 0.50 per 1000 carbons, or greater than 0.50
per 1000 carbons, or at least 0.55 per 1000 carbons, or greater
than 0.55 per 1000 carbons, or at least 0.60 per 1000 carbons, or
greater than 0.60 per thousand carbons, or at least 0.65 per 1000
carbons, or greater than 0.65 per 1000 carbons, or at least 0.70
per 1000 carbons, or greater than 0.70 per 1000 carbons, or at
least 0.75 per 1000 carbons, or greater than 0.75 per 1000
carbons.
[0118] Suitable alpha olefin comonomers for polymerization with
ethylene to make the polyethylene copolymer include 1-butene,
1-hexene, and 1-octene.
[0119] In an embodiment of the disclosure, the polyethylene
copolymer includes from about 0.1 to about 5 weight %, in some
cases less than about 3 weight %, in other instances less than
about 1.5 weight % of an alpha olefin chosen from 1-butene,
1-hexene, 1-octene, and mixtures thereof.
[0120] In an embodiment of the disclosure, the polyethylene
copolymer includes polymerized ethylene and 1-butene.
[0121] Examples of polyethylene copolymers which are useful in the
present disclosure include by way of non-limiting example,
SCLAIR.RTM. 17A, and SCLAIR.RTM. 58A, each of which is commercially
available from NOVA CHEMICALS.RTM..
[0122] In an embodiment of the disclosure, the polyethylene
copolymers suitable for use in the present disclosure may be
prepared using conventional polymerization processes, non-limiting
examples of which include gas phase, slurry and solution phase
polymerization processes. Such processes are well known to those
skilled in the art.
[0123] In an embodiment of the disclosure, the polyethylene
copolymers may be prepared using conventional catalysts. Some
non-limiting examples of conventional catalysts include chrome
based catalysts and Ziegler-Natta catalysts. Such catalysts are
well known to those skilled in the art.
[0124] Solution and slurry polymerization processes are generally
conducted in the presence of an inert hydrocarbon solvent/diluent,
such for example, a C.sub.4-12 hydrocarbon which may be
unsubstituted or substituted by a C.sub.1-4 alkyl group, such as,
butane, pentane, hexane, heptane, octane, cyclohexane,
methylcyclohexane, or hydrogenated naphtha. A non-limiting example
of a commercial solvent is ISOPAR.RTM. E (C.sub.8-12 aliphatic
solvent, Exxon Chemical Co.). The monomers are dissolved in the
solvent/diluent.
[0125] A slurry polymerization process may be conducted at
temperatures from about 20.degree. C. to about 180.degree. C., or
from 80.degree. C. to about 150.degree. C., and the polyethylene
polymer being made is insoluble in the liquid hydrocarbon
diluent.
[0126] A solution polymerization process may be conducted at
temperatures of from about 180.degree. C. to about 250.degree. C.,
or from about 180.degree. C. to about 230.degree. C., and the
polyethylene polymer being made is soluble in the liquid
hydrocarbon phase (e.g., the solvent).
[0127] A gas phase polymerization process can be carried out in
either a fluidized bed or a stirred bed reactor. A gas phase
polymerization typically involves a gaseous mixture including from
about 0 to about 15 mole % of hydrogen, from about 0 to about 30
mole % of one or more C.sub.3-8 alpha-olefins, from about 15 to
about 100 mole % of ethylene, and from about 0 to about 75 mole %
of an inert gas at a temperature from about 50.degree. C. to about
120.degree. C., or from about 75.degree. C. to about 110.degree.
C.
[0128] Suitable alpha olefins which may be polymerized with
ethylene in the case of a polyethylene copolymer are C.sub.3-8
alpha olefins such as one or more of 1-butene, 1-hexene, and
1-octene.
[0129] In an embodiment of the disclosure, the polyethylene
copolymer is prepared by contacting ethylene and optionally an
alpha-olefin with a polymerization catalyst under solution
polymerization conditions.
[0130] In an embodiment of the disclosure, the polyethylene
copolymer is made in a single polymerization reactor using only one
polymerization catalyst.
[0131] In an embodiment of the disclosure, the polyethylene
copolymer is made in a multiple (i.e. two or more) polymerization
reactors using only one polymerization catalyst.
[0132] In an embodiment of the disclosure, the polyethylene
copolymer is made in a single solution polymerization reactor using
only one polymerization catalyst.
[0133] In an embodiment of the disclosure, the polyethylene
copolymer is made in multiple (i.e. two or more) solution
polymerization reactors using only one polymerization catalyst.
[0134] In an embodiment of the disclosure, the polyethylene
copolymer is made in a single solution polymerization reactor using
only one polymerization catalyst, and the polymerization catalyst
is a Ziegler-Natta catalyst.
[0135] In an embodiment of the disclosure, the polyethylene
copolymer is made in multiple (i.e. two or more) solution
polymerization reactors using only one polymerization catalyst, and
the polymerization catalyst is a Ziegler-Natta catalyst.
[0136] In an embodiment of the disclosure, the polyethylene
copolymer is made with a Ziegler-Natta polymerization catalyst.
[0137] In an embodiment of the disclosure, the polyethylene
copolymer is made in a solution polymerization process using a
Ziegler-Natta catalyst.
[0138] The term "Ziegler-Natta" catalyst is well known to those
skilled in the art and is used herein to convey its conventional
meaning. A Zielger-Natta catalyst may be supported or
unsupported.
[0139] By way of non-limiting example, Ziegler-Natta catalysts
include at least one transition metal compound of a transition
metal selected from groups 3, 4, or 5 of the Periodic Table (using
IUPAC nomenclature) and an organoaluminum component that is defined
by the formula:
Al(X').sub.a(OR).sub.b(R).sub.c
wherein: X' is a halide (for example chlorine); OR is an alkoxy or
aryloxy group; R is a hydrocarbyl (for example an alkyl having from
1 to 10 carbon atoms); and a, b, or c are each 0, 1, 2, or 3 with
the provisos, a+b+c=3 and b+c.gtoreq.1. As will be appreciated by
those skilled in the art of ethylene polymerization, conventional
Ziegler-Natta catalysts may also incorporate additional components
such as an electron donor or support materials. For example, an
amine electron donor or a magnesium compound or a magnesium alkyl
such as butyl ethyl magnesium and a halide source (for example a
chloride such as tertiary butyl chloride) and which may form a
support matrix (such as MgCl.sub.2 or chloride deficient MgCl.sub.2
both of which are well known in the art). Ziegler-Natta catalyst
components may be combined off-line or they may be combined in-line
on route to a polymerization zone or they may be combined directly
within a polymerization reactor zone. Ziegler-Natta catalysts may
also be "tempered" (i.e. heat treated) prior to being introduced to
a reactor (again, using techniques which are well known to those
skilled in the art and published in the literature).
[0140] In an embodiment of the disclosure, the polyethylene
copolymer has less than 1.5 ppm, or less than 1.3 ppm, or
.ltoreq.1.0 ppm, or .ltoreq.0.9 ppm, or .ltoreq.0.8, or less than
0.8 ppm, or .ltoreq.0.75 ppm, or less than 0.50 ppm of titanium
(Ti) present.
[0141] In an embodiment of the disclosure, the polyethylene
copolymer has less than 1.5 ppm, or less than 1.3 ppm, or
.ltoreq.1.0 ppm, or .ltoreq.0.9 ppm, or .ltoreq.0.8 ppm, or
.ltoreq.0.75, or .ltoreq.0.60 ppm of aluminum (Al) present.
[0142] In an embodiment of the disclosure, the polyethylene
copolymer has less than 0.5 ppm, or less than 0.4 ppm, or
.ltoreq.0.3 ppm, or .ltoreq.0.2 ppm, or .ltoreq.0.15 ppm, or
.ltoreq.0.1 ppm, of chlorine (CI) present.
[0143] In an embodiment of the disclosure, the polyethylene
copolymer has less than 4.0 ppm, or less than 3.0 ppm, or
.ltoreq.2.5 ppm, or .ltoreq.2.0 ppm, of magnesium (Mg) present.
[0144] In an embodiment of the disclosure, the polyethylene
copolymer includes one or more nucleating agents.
[0145] In an embodiment of the disclosure, the polyethylene
copolymer includes a nucleating agent or a mixture of nucleating
agents.
[0146] The polyethylene copolymer may be compounded or dry-blended
either by a manufacturer or a converter (e.g., the company
converting the resin pellets into the final product). The
compounded or dry-blended polyethylene copolymers may contain
fillers, pigments and other additives. Typically, fillers are inert
additives, such as, clay, talc, TiO.sub.2 and calcium carbonate,
which may be added to the polyolefin copolymer in amounts from
about 0 weight % up to about 50 weight %, in some cases, less than
30 weight % of fillers are added. The compounded or dry-blended
polyethylene copolymers may contain antioxidants, heat and light
stabilizers, such as, combinations of one or more of hindered
phenols, phosphates, phosphites and phosphonites, typically, in
amounts of less than about 0.5 weight % based on the weight of the
polyethylene polymer. Pigments may also be added to the
polyethylene copolymers in small amounts. Non-limiting examples of
pigments include carbon black, phthalocyanine blue, Congo red,
titanium yellow, etc.
[0147] The polyethylene copolymers may contain a nucleating agent
or a mixture of nucleating agents in amounts of from about 5 parts
per million (ppm) to about 10,000 ppm based on the weight of the
polyethylene polymer. The nucleating agent may be chosen from
dibenzylidene sorbitol, di(p-methylbenzylidene) sorbitol,
di(o-methylbenzylidene) sorbitol, di(p-ethylbenzylidene) sorbitol,
bis(3,4-dimethylbenzylidene) sorbitol, bis(3,4-diethylbenzylidene)
sorbitol and bis(trimethylbenzylidene) sorbitol. One commercially
available nucleating agent is bis(3,4-dimethylbenzylidene)
sorbitol.
[0148] Optionally, additives can be added to the polyethylene
copolymer. Additives can be added to the polyethylene copolymer
during an extrusion or compounding step, but other suitable known
methods will be apparent to a person skilled in the art. The
additives can be added as is or as part of a separate polymer
component added during an extrusion or compounding step. Suitable
additives are known in the art and include but are not-limited to
antioxidants, phosphites and phosphonites, nitrones, antacids, UV
light stabilizers, UV absorbers, metal deactivators, dyes, fillers
and reinforcing agents, nano-scale organic or inorganic materials,
antistatic agents, lubricating agents such as calcium stearates,
slip additives such as erucimide and behenamide, and nucleating
agents (including nucleators, pigments or any other chemicals which
may provide a nucleating effect to the polyethylene copolymer). The
additives that can be optionally added are typically added in
amount of up to 20 weight percent (wt %).
[0149] One or more nucleating agent(s) may be introduced into the
polyethylene copolymer by kneading a mixture of the polymer,
usually in powder or pellet form, with the nucleating agent, which
may be utilized alone or in the form of a concentrate containing
further additives such as stabilizers, pigments, antistatics, UV
stabilizers and fillers. It may be a material which is wetted or
absorbed by the polymer, which may be insoluble in the polymer and
which may have a melting point higher than that of the polymer, and
it may be homogeneously dispersible in the polymer melt in as fine
a form as possible (1 to 10 .mu.m). Compounds known to have a
nucleating capacity for polyolefins include salts of aliphatic
monobasic or dibasic acids or arylalkyl acids, such as sodium
succinate, or aluminum phenylacetate; and alkali metal or aluminum
salts of aromatic or alicyclic carboxylic acids such as sodium
.beta.-naphthoate, or sodium benzoate.
[0150] Examples of nucleating agents which are commercially
available and which may be added to the polyethylene copolymer are
dibenzylidene sorbital esters (such as the products sold under the
trademark Millad 3988.TM. by Milliken Chemical and IRGACLEAR.RTM.
by Ciba Specialty Chemicals). Further examples of nucleating agents
which may added to the polyethylene copolymer include the cyclic
organic structures disclosed in U.S. Pat. No. 5,981,636 (and salts
thereof, such as disodium bicyclo [2.2.1] heptene dicarboxylate);
the saturated versions of the structures disclosed in U.S. Pat. No.
5,981,636 (as disclosed in U.S. Pat. No. 6,465,551; Zhao et al., to
Milliken); the salts of certain cyclic dicarboxylic acids having a
hexahydrophtalic acid structure (or "HHPA" structure) as disclosed
in U.S. Pat. No. 6,599,971 (Dotson et al., to Milliken); and
phosphate esters, such as those disclosed in U.S. Pat. No.
5,342,868 and those sold under the trade names NA-11 and NA-21 by
Asahi Denka Kogyo, cyclic dicarboxylates and the salts thereof,
such as the divalent metal or metalloid salts, (for example,
calcium salts) of the HHPA structures disclosed in U.S. Pat. No.
6,599,971. For clarity, the HHPA structure generally includes a
ring structure with six carbon atoms in the ring and two carboxylic
acid groups which are substituents on adjacent atoms of the ring
structure. The other four carbon atoms in the ring may be
substituted, as disclosed in U.S. Pat. No. 6,599,971. An example is
1,2-cyclohexanedicarboxylicacid, calcium salt (CAS registry number
491589-22-1). Still further examples of nucleating agents which may
added to the polyethylene copolymer include those disclosed in
WO2015042561, WO2015042563, WO2015042562 and WO 2011050042.
[0151] Many of the above described nucleating agents may be
difficult to mix with the polyethylene copolymer that is being
nucleated and it is known to use dispersion aids, such as, for
example, zinc stearate, to mitigate this problem.
[0152] In an embodiment of the disclosure, the nucleating agents
are well dispersed in the polyethylene copolymer.
[0153] In an embodiment of the disclosure, the amount of nucleating
agent used is comparatively small--from 5 to 3000 parts by million
per weight (based on the weight of the polyethylene copolymer) so
it will be appreciated by those skilled in the art that some care
is taken to ensure that the nucleating agent is well dispersed. In
an embodiment of the disclosure, the nucleating agent is added in
finely divided form (less than 50 microns, for example less than 10
microns) to the polyethylene copolymer to facilitate mixing. In
some embodiments, this type of "physical blend" (i.e., a mixture of
the nucleating agent and the resin in solid form) may be preferable
to the use of a "masterbatch" of the nucleator (where the term
"masterbatch" refers to the practice of first melt mixing the
additive--the nucleator, in this case--with a small amount of the
polyethylene copolymer resin--then melt mixing the "masterbatch"
with the remaining bulk of the polyethylene copolymer resin).
[0154] In an embodiment of the disclosure, an additive such as
nucleating agent may be added to the polyethylene copolymer by way
of a "masterbatch", where the term "masterbatch" refers to the
practice of first melt mixing the additive (e.g., a nucleator) with
a small amount of the polyethylene copolymer, followed by melt
mixing the "masterbatch" with the remaining bulk of the
polyethylene copolymer.
[0155] In an embodiment of the disclosure, the polyethylene
copolymer further includes a nucleating agent or a mixture of
nucleating agents.
[0156] Since the polyethylene composition is used in bottle closure
assemblies typically used for food contact applications, the
additive package should meet the appropriate food regulations, such
as, the FDA regulations in the United States.
[0157] In an embodiment of the disclosure, the polyethylene
copolymer described above is used in the formation of molded
articles. For example, articles formed by continuous compression
molding and injection molding are contemplated. Such articles
include, for example, bottle closure assemblies, caps, hinged caps,
screw caps, closures and hinged closures for bottles.
[0158] The polyethylene copolymers described above are used in the
formation of bottle closure assemblies. For example, bottle closure
assemblies formed in part on in whole by compression molding and/or
injection molding are contemplated.
[0159] In one embodiment, the bottle closure assembly includes the
polyethylene copolymer described above has good organoleptic
properties. The bottle closure assemblies are well suited for
sealing bottles, containers, and the like, for examples bottles
that may contain drinkable water, and other foodstuffs, including
but not limited to liquids that are pressurized (e.g., carbonated
beverages or appropriately pressurized drinkable liquids). The
bottle closure assemblies may also be used for sealing bottles
containing drinkable water or non-carbonated beverages (e.g.,
juice). Other applications include bottle closure assemblies for
bottles and containers containing foodstuffs, such as for example
ketchup bottles and the like.
[0160] The bottle closure assemblies of the current disclosure can
be made according to any known method, including for example
injection molding and compression molding techniques that are well
known to persons skilled in the art. Hence, in an embodiment of the
disclosure, a bottle closure assembly including polyethylene
copolymer (defined above) is prepared with a process including at
least one compression molding step and/or at least one injection
molding step.
[0161] Further non-limiting details of the disclosure are provided
in the following examples. The examples are presented for the
purpose of illustrating selected embodiments of this disclosure, it
being understood that the examples presented do not limit the
claims presented.
Examples
[0162] Melt indexes, I.sub.2,I.sub.5,I.sub.6 and I.sub.21 for the
polyethylene copolymer were measured according to ASTM D1238 (when
conducted at 190.degree. C., using a 2.16 kg, a 5 kg, a 6.48 kg and
a 21 kg weight respectively).
[0163] M.sub.n, M.sub.w, and M.sub.z (g/mol) were determined by
high temperature Gel Permeation Chromatography with differential
refractive index detection using universal calibration (e.g.,
ASTM-D6474-99). GPC data was obtained using an instrument sold
under the trade name "Waters 150c", with 1,2,4-trichlorobenzene as
the mobile phase at 140.degree. C. The samples were prepared by
dissolving the polymer in this solvent and were run without
filtration. Molecular weights are expressed as polyethylene
equivalents with a relative standard deviation of 2.9% for the
number average molecular weight ("M.sub.n") and 5.0% for the weight
average molecular weight ("M.sub.w"). The molecular weight
distribution (MWD) is the weight average molecular weight divided
by the number average molecular weight, M.sub.w/M.sub.n. The
z-average molecular weight distribution is M.sub.z/M.sub.n. Polymer
sample solutions (1 to 2 mg/mL) were prepared by heating the
polymer in 1,2,4-trichlorobenzene (TCB) and rotating on a wheel for
4 hours at 150.degree. C. in an oven. The antioxidant
2,6-di-tert-butyl-4-methylphenol (BHT) was added to the mixture in
order to stabilize the polymer against oxidative degradation. The
BHT concentration was 250 ppm. Sample solutions were
chromatographed at 140.degree. C. on a PL 220 high-temperature
chromatography unit equipped with four Shodex columns (HT803,
HT804, HT805 and HT806) using TCB as the mobile phase with a flow
rate of 1.0 mL/minute, with a differential refractive index (DRI)
as the concentration detector. BHT was added to the mobile phase at
a concentration of 250 ppm to protect the columns from oxidative
degradation. The sample injection volume was 200 mL. The raw data
were processed with CIRRUS.RTM. GPC software. The columns were
calibrated with narrow distribution polystyrene standards. The
polystyrene molecular weights were converted to polyethylene
molecular weights using the Mark-Houwink equation, as described in
the ASTM standard test method D6474.
[0164] Primary melting peak (.degree. C.), heat of fusion (J/g) and
crystallinity (%) was determined using differential scanning
calorimetry (DSC) as follows: the instrument was first calibrated
with indium; after the calibration, a polymer specimen is
equilibrated at 0.degree. C. and then the temperature was increased
to 200.degree. C. at a heating rate of 10.degree. C./min; the melt
was then kept isothermally at 200.degree. C. for five minutes; the
melt was then cooled to 0.degree. C. at a cooling rate of
10.degree. C./min and kept at 0.degree. C. for five minutes; the
specimen was then heated to 200.degree. C. at a heating rate of
10.degree. C./min. The DSC Tm, heat of fusion and crystallinity are
reported from the 2.sup.nd heating cycle.
[0165] The short chain branch frequency (SCB per 1000 carbon atoms)
of the polyethylene copolymer was determined by Fourier Transform
Infrared Spectroscopy (FTIR) as per the ASTM D6645-01 method. A
Thermo NICOLET.RTM. 750 Magna-IR Spectrophotometer equipped with
OMNIC.RTM. version 7.2a software was used for the measurements.
Unsaturations in the polyethylene copolymer (terminal, side chain
and internal) were also determined by Fourier Transform Infrared
Spectroscopy (FTIR) as per ASTM D3124-98. Comonomer content can
also be measured using .sup.13C NMR techniques as discussed in
Randall, Rev. Macromol. Chem. Phys., C29 (2&3), p 285; U.S.
Pat. No. 5,292,845 and WO 2005/121239.
[0166] Polyethylene copolymer density (g/cm.sup.3) was measured
according to ASTM D792.
[0167] Hexane extractables were determined according to ASTM
D5227.
[0168] To determine CDBI(50), a solubility distribution curve is
first generated for the polyethylene copolymer. This is
accomplished using data acquired from the TREF technique. This
solubility distribution curve is a plot of the weight fraction of
the copolymer that is solubilized as a function of temperature.
This is converted to a cumulative distribution curve of weight
fraction versus comonomer content, from which the CDBI(50) is
determined by establishing the weight percentage of a copolymer
sample that has a comonomer content within 50% of the median
comonomer content on each side of the median (See WO 93/03093 and
U.S. Pat. No. 5,376,439). The CDBI(25) is determined by
establishing the weight percentage of a copolymer sample that has a
comonomer content within 25% of the median comonomer content on
each side of the median
[0169] The temperature rising elution fractionation (TREF) method
used herein was as follows. Polymer samples (50 to 150 mg) were
introduced into the reactor vessel of a crystallization-TREF unit
(Polymer Char). The reactor vessel was filled with 20 to 40 ml
1,2,4-trichlorobenzene (TCB), and heated to the desired dissolution
temperature (e.g., 150.degree. C.) for 1 to 3 hours. The solution
(0.5 to 1.5 ml) was then loaded into the TREF column filled with
stainless steel beads. After equilibration at a given stabilization
temperature (e.g., 110.degree. C.) for 30 to 45 minutes, the
polymer solution was allowed to crystallize with a temperature drop
from the stabilization temperature to 30.degree. C. (0.1 or
0.2.degree. C./minute). After equilibrating at 30.degree. C. for 30
minutes, the crystallized sample was eluted with TCB (0.5 or 0.75
mL/minute) with a temperature ramp from 30.degree. C. to the
stabilization temperature (0.25 or 1.0.degree. C./minute). The TREF
column was cleaned at the end of the run for 30 minutes at the
dissolution temperature. The data were processed using Polymer Char
software, Excel spreadsheet and TREF software developed
in-house.
[0170] High temperature GPC equipped with an online FTIR detector
(GPC-FTIR) was used to measure the comonomer content as the
function of molecular weight.
[0171] Plaques molded from the polyethylene copolymers were tested
according to the following ASTM methods: Bent Strip Environmental
Stress Crack Resistance (ESCR) at Condition B at 10% and 100%
IGEPAL.RTM. CO-630 at 50.degree. C., ASTM D1693; notched Izod
impact properties, ASTM D256; Flexural Properties, ASTM D790;
Tensile properties, ASTM D638; Vicat softening point, ASTM D1525;
Heat deflection temperature, ASTM D648.
[0172] The polymer used in Example 1 is a polyethylene
ethylene/1-hexene copolymer and has a density of 0.957 g/cm.sup.3,
a melt index 12 of 0.46 g/10 min and is commercially available from
EXXONMOBIL.RTM. as EXXONMOBIL.RTM. HPDE HD 9856B.
[0173] The polymer used in Example 2 is a polyethylene copolymer
made with a chromium-based polymerization catalyst in a gas phase
polymerization process. The Example 2 polymer is an
ethylene/1-hexene copolymer and has a density of 0.949 g/cm.sup.3,
a melt index 12 of 0.40 g/10 min and is commercially available from
NOVA CHEMICALS.RTM. as NOVAPOL.RTM. HF-Y450-A.
[0174] The polymer used in Example 3 is a polyethylene copolymer
made with a Ziegler-Natta catalyst in a solution polymerization
process. The Example 3 polymer is an ethylene/1-butene copolymer,
and has a density of 0.950 g/cm.sup.3, a melt index 12 of 0.45 g/10
min and is commercially available from NOVA CHEMICALS.RTM. as
SCLAIR.RTM. 17A. A GPC profile for the polymer of Example 3 is
shown in FIG. 8.
[0175] The polymer used in Example 4 is a polyethylene copolymer
made with a Ziegler-Natta catalyst in a solution polymerization
process. The Example 4 polymer is an ethylene/1-butene copolymer,
and has a density of 0.957 g/cm.sup.3, a melt index 12 of 0.41 g/10
min and is commercially available from NOVA CHEMICALS.RTM. as
SCLAIR.RTM. 58A. A GPC profile for the polymer of Example 4 is
shown in FIG. 9.
[0176] Further data for each of the polymers used in Examples 1-4
is provided in Table 1 together with their plaque data.
TABLE-US-00001 TABLE 1 Polymer and Plaque Properties Example No. 1
2 3 4 Density (g/cm.sup.3) 0.957 0.949 0.950 0.957 Melt Index
I.sub.2 0.46 0.40 0.45 0.41 (g/10 min) Melt Flow Ratio
(I.sub.21/I.sub.2) 93.8 83.9 96.7 Stress Exponent 1.89 1.78 1.86
M.sub.n 13959 14344 17949 13786 M.sub.w 146950 122544 165205 160821
M.sub.z 875145 602266 938029 911830 Polydispersity Index
(M.sub.w/M.sub.n) 10.53 8.54 9.20 11.67 M.sub.z/M.sub.w 5.96 4.91
5.68 5.67 Branch Frequency - FTIR (uncorrected for chain end
--CH.sub.3) Uncorrected SCB/1000 C <0.5 2.7 1.2 <0.5
Uncorrected comonomer content <0.1 0.5 0.2 <0.1 (mol %)
Internal unsaturation (/1000 C) 0.050 0.070 0.040 Side chain
unsaturation (/1000 C) 0.110 0.040 0.020 Terminal unsaturation
(/1000 C) 1.130 0.800 0.730 Total unsaturation 1.29 0.910 0.790
Comonomer ID 1-hexene 1-hexene 1-butene 1-butene TREF CDBI.sub.50
(%) 66.8 58.3 70.8 69.1 TREF CDBI.sub.25 (%) 46.6 36.2 58.3 60 DSC
Primary Melting Peak (.degree. C.) 131.61 128.47 129.74 132.23 Heat
of Fusion (J/g) 219.2 194.00 207.40 210.10 Crystallinity (%) 75.57
66.89 71.51 72.46 Environmental Stress Crack Resistance ESCR Cond.
A at 100% (hrs) 151 -- -- -- ESCR Cond. B at 100% (hrs) -- >1154
93 44 ESCR Cond. B at 10% (hrs) 66 73 44 26 Flexural Properties
(Plaques) Flex Secant Mod. 2% (MPa) 928 951 1165 Impact Properties
(Plaques) Izod Impact (ft-lb/in) 2.50 1.40 1.90 Other properties
Hexane Extractables (%) 0.57 0.85 0.53 VICAT Soft. Pt. (.degree.
C.) - Plaque 124.7 126.2 129.1 Heat Deflection Temp. [.degree. C.]
@ 66 PSI 64.7 62 72.9
Neutron Activation Analysis (NAA)
[0177] Neutron Activation Analysis, hereafter NAA, was used to
determine catalyst residues in ethylene polymers and was performed
as follows. A radiation vial (composed of ultrapure polyethylene, 7
mL internal volume) was filled with a polyethylene polymer product
sample and the sample weight was recorded. Using a pneumatic
transfer system the sample was placed inside a SLOWPOKE.RTM.
nuclear reactor (Atomic Energy of Canada Limited, Ottawa, Ontario,
Canada) and irradiated for 30 to 600 seconds for short half-life
elements (e.g., Ti, V, Al, Mg, and Cl) or 3 to 5 hours for long
half-life elements (e.g., Zr, Hf, Cr, Fe and Ni). The average
thermal neutron flux within the reactor was
5.times.10.sup.11/cm.sup.2/s. After irradiation, samples were
withdrawn from the reactor and aged, allowing the radioactivity to
decay; short half-life elements were aged for 300 seconds or long
half-life elements were aged for several days. After aging, the
gamma-ray spectrum of the sample was recorded using a germanium
semiconductor gamma-ray detector (ORTEC.RTM. model GEM55185,
Advanced Measurement Technology Inc., Oak Ridge, Tenn., USA) and a
multichannel analyzer (ORTEC model DSPEC Pro). The amount of each
element in the sample was calculated from the gamma-ray spectrum
and recorded in parts per million relative to the total weight of
the polymer sample. The N.A.A. system was calibrated with Specpure
standards (1000 ppm solutions of the desired element (greater than
99% pure)). One mL of solutions (elements of interest) were
pipetted onto a 15 mm.times.800 mm rectangular paper filter and air
dried. The filter paper was then placed in a 1.4 mL polyethylene
irradiation vial and analyzed by the N.A.A. system. Standards are
used to determine the sensitivity of the N.A.A. procedure (in
counts/.mu.g). The results of NAA analysis (i.e. catalyst residue
levels in ppm, present in the polymer based on the weight of the
polymer) for Examples 2-4 are given in Table 2.
TABLE-US-00002 TABLE 2 NAA of Polyethylene Polymers Example No. 2 3
4 Cr (ppm) 0.72 <0.1 <0.2 Al (ppm) 1.1 0.92 0.74 Cl (ppm)
0.19 0.06 0.05 Mg (ppm) <2 <2 <2 Ti (ppm) 0.45 0.32
0.46
Evaluation of Organoleptics/Water Taste Testing
[0178] Caps made from the polymer of Example 1 were used for the
water taste testing outlined below. The caps were 2.5 g with a
surface area of 48.26 cm.sup.2. 20 caps were used to give a total
surface area of 965 cm.sup.2. Plaque specimens were prepared, and
then cut to a predetermined size, for testing the polymers used in
Examples 2 and 3.
[0179] For the polymers of Examples 2 and 3, a melt was prepared
from polymer pellets by using a Brabender compounder at a melt
temperature of 170.degree. C. and rpm of 100. Next, 145 g of the
melted polymer was pressed into a compression molded plaque having
the dimensions 10 inches by 10 inches and a 75 mil thickness. The
plaque was wrapped in aluminum foil and stored in the freezer.
Plaques were trimmed to a size of less than 24 cm by 21 cm to give
a total surface area of 965 cm.sup.2 and then cut into 6 pieces so
that the pieces could be placed in a Mason jar. The 6 plaque pieces
obtained in this manner for each of Examples 2 and 3, as well as
the 20 caps for Example 1 were placed in clean Mason jars which
were then filled with approximately 1 liter of bottled spring water
(REAL CANADIAN Natural Spring Water.TM.). Each jar was sealed with
a piece of aluminum foil and a lid. For use as a control, bottled
spring water was also added to a Mason jar in the absence of
polymer plaque pieces or caps. Each of the jars (including the
control) was placed in a 60.degree. C. water bath for 4 hours. The
jars were then removed from the bath and the plaques or caps were
removed from the jars. The jars were resealed and all the jars were
left to cool to room temperature. Water samples for the taste panel
were prepared by pouring the above sample water from each of the
jars into separate 2 ounce polystyrene sample cups, each with an
identifying code attached to it. For each water sample, a randomly
generated 3 digit code was used to ensure the tasting was a blind
tasting where panelists were not given information about the water
samples they were tasting. Each panelist was provided with an
instruction sheet that explains how to conduct the taste test.
Before the test, the palate is cleansed with an unsalted cracker.
Up to six water samples, including a control, were tasted by each
panelist. The same water samples were tasted by each panelist. The
water samples were presented in one of four different orders. The
panelists ranked each water sample on the following scale to
provide a "water taste testing score": 7=Completely Acceptable (no
flavor or taste detected); 6=Moderately Acceptable; 5=Slightly
Acceptable; 4=Neither Acceptable nor Unacceptable; 3=Slightly
Unacceptable; 2=Moderately Unacceptable; 1=Completely Unacceptable.
If a panelist does not detect the control, by assigning the control
a score of 5 or higher, the results from that panelist were not
included in the final statistical analysis. The results are
analyzed using analysis of variance and an average water taste
testing score is reported for each water sample as shown in Table
3.
TABLE-US-00003 TABLE 3 Organoleptics (Water Taste Testing Score)
Example No. Control (spring water stored 1 2 3 in glass jar) Taste
Panel Rating - average water 3.3 2.9 6 6.7 taste testing score
Taste Panel Rating - standard error 0.44 0.48 0.3 0.09
[0180] As can be seen from the data in Table 3, each of the water
samples containing caps made from the resin of Example 1 or plaque
material made from the resin of Example 2 had poor performance
using the water taste testing procedure. In contrast, the water
samples containing plaque material made from the resin of Example
3, had a performance just below that of the control sample,
consistent with very good organoleptic properties for this
material. Good organoleptic properties are desirable when making a
bottle closure or a cap portion of a bottle closure assembly when
they are not used in combination with a liner. This is because the
closure or cap portion may come in direct contact with consumable
liquid or foodstuffs held within the bottle, container, or the
like, which the closure or cap portion (of a bottle closure
assembly) is sealing.
[0181] A comparison of Table 3 with the catalyst component residue
data in Table 2, is consistent with the fact that when higher
levels of catalyst residue remain in a polyethylene polymer it
leads to poorer organoleptic properties. Compare for example, the
catalyst residues present in Example 2, with the catalyst residues
present in Example 3. Example 2 has 0.72 ppm or chromium present,
an aluminum residue level of greater than 1 ppm, and 0.19 ppm of
chlorine. In contrast, Example 3 has negligible amounts of chromium
present, less than 1 ppm of aluminum and 0.06 ppm of chlorine
present. For similar reasons, a person skilled in the art would
expect Example 4 to have good organoleptic properties, as it has
low levels of catalyst residues present. In contrast, the poor
taste testing performance of Example 1, indicates that there may be
significant levels of catalyst component residues present.
[0182] For end use applications, especially those which may come in
contact with foodstuff it may be desirable to employ products
having lower levels of catalyst component residues. Lower catalyst
residues may lead to better organoleptic properties and help
preserve the original taste and odor of the packaged contents.
[0183] The polyethylene copolymers described above can be used in
the formation of bottle closure assemblies. For example, bottle
closure assemblies formed in part on in whole by compression
molding and/or injection molding are contemplated.
[0184] In one embodiment, the bottle closure assembly includes the
polyethylene copolymers described above and has good organoleptic
properties. Hence the bottle closure assemblies are well suited for
sealing bottles, containers, and the like, for example bottles that
may contain drinkable water, and other foodstuffs, including but
not limited to liquids that are pressurized or non-pressurized.
[0185] In an embodiment of the disclosure, a bottle closure
assembly including a polyethylene copolymer defined as above is
prepared with a process including at least one compression molding
step and/or at least one injection molding step.
Preparation of a Tether Proxy for Deformation Testing
[0186] In order to provide a proxy of a tether portion which can be
analyzed under conditions of shear, tear and tensile deformation, a
closure (see FIGS. 10A and 10B) was compression molded as described
below and then a tamper evident band, 10* (a proxy for a retaining
means portion, 10) was formed by folding in and cutting the bottom
circular edge of the closure using a folding/slitting machine with
a modified blade, so that a tamper evident band (10*) which was
joined to the cap portion (1) by several narrow ("pin" like)
connecting sections (marked by the frangible line, 9 in FIGS. 10A
and 10B) and one larger continuous section (i.e. continuous with a
portion of the cap portion side wall), with the larger continuous
section serving as a proxy for a tether (the area marked as 40 in
FIGS. 10A and 10B). The larger continuous section or "tether proxy"
section was designed to have an arcuate length of 6 mm. The "tether
proxy" section had a cross-sectional width (or thickness) of 0.6 mm
as determined by the dimensions of the closure mold used for the
compression molding process (see below). The "tether proxy"
section, or simply "tether proxy" 40 was then subjected to shear
and tear deformations and to tensile deformation using a toque
tester unit and tensile tester unit respectively (see below).
Method of Making a Closure by Compression Molding
[0187] A SACMI Compression molding machine (model CCM24SB) and a
PCO (plastic closure only) 1881 carbonated soft drink (CSD) closure
mold was used to prepare the closures. Depending on material
density, melt index (12) and chosen plug size, the closure weight
varied between 2.15 g and 2.45 grams, with the process conditions
adjusted to target a closure having a weight of about 2.3 grams.
During the closure preparation process, the overall closure
dimensions, such as, for the example, the closure diameter and the
closure height were measured and maintained within desired
"quality-controlled" specifications. Closures with poor circularity
or with significant deformation away from the pre-defined
specifications were rejected by an automatic vision system
installed on the compression molding machine. Once the closure had
been compression molded, a tamper evident band, inclusive of one
larger continuous section (a proxy for a tether portion) was cut
into the closure bottom edge using a folding/slitting machine
fitted with a modified blade. Both experimental and simulated data
confirmed that 99% of any closure weight differences were due to
differences in the top panel thickness (of the cap portion, see
FIG. 10A) for each of the compression molded closures. For example,
in the closures prepared by compression molding, the top panel
thickness values of closures having a weight ranging from 2.15
grams to 2.45 grams were found to be slightly different, but each
of the closure side wall thicknesses were found to be identical. As
a result, any small differences in the compression molded cap
weight were expected to have no impact on the dimensions of the
tamper evident band or the tether proxy section (see above): in
each case, the tether proxy had an arcuate length of 6 mm and a
cross-sectional thickness of 0.6 mm.
[0188] Type 1 closures were compression molded from an
ethylene/1-butene copolymer (Example 4), having a density of 0.957
g/cm.sup.3, a melt index 12 of 0.41 g/10 min and which is
commercially available from NOVA CHEMICALS.RTM. as SCLAIR.RTM.
58A.
[0189] Type 2 closures (Comparative) were compression molded from a
unimodal polyethylene copolymer of ethylene and 1-butene having a
melt index 12 of 32 g/10 min, a density of 0.951 g/cm.sup.3, and a
molecular weight distribution, M.sub.w/M.sub.n of 2.88, and which
is made using a Ziegler-Natta catalyst in a solution olefin
polymerization process. This resin is commercially available from
NOVA CHEMICALS.RTM. as SCLAIR.RTM. 2712.
[0190] The compression molding conditions used to make each closure
type are provided in Table 4.
TABLE-US-00004 TABLE 4 Compression Molding Processing Conditions
Closure Type No. 2 1 (Comparative) Closure Weight (g) 2.3 2.39 BT1
Temp (.degree. C.) 168 163 BT2 Temp (.degree. C.) 170 164 BT3 Temp
(.degree. C.) 174 163 BT4 Temp (.degree. C.) 175 161 BT6 Temp
(.degree. C.) 175 170 BT7 Temp (.degree. C.) 185 187 BT8 Temp
(.degree. C.) 185 184 BT9 Temp (.degree. C.) 185 184 BT15 Temp
(.degree. C.) 175 170 BT16 Temp (.degree. C.) 174 165 BT17 Temp
(.degree. C.) 182 174 Metering Pump Set Press 50 50 (bar) Metering
Pump Actual Press 50 50 1 (bar) IN Metering Pump Actual Press 146
30.6 2 (bar) OUT Pump Speed (%) 59 57 Hydraulic Operating Temp 45
46 (.degree. C.) Punch Cooling BT18 (.degree. C.) 20 20 Cavity
Cooling BT19 (.degree. C.) 20 20 Ausiliari Cooling BT20 (.degree.
C.) 30 30
Shear Deformation of a Tether Proxy
[0191] A TMS 5000 Torque Tester unit manufactured by Steinfurth was
used to carry out the tether proxy shear deformation testing. The
unit was adjusted to operate in "removal torque mode". A closure
having a tether proxy section (area 40 in FIGS. 10A and 10B) with a
6 mm arcuate length and a 0.6 mm cross-sectional width connecting a
cap portion (1) to a tamper evident band 10* (a proxy for a
retaining means portion, 10) and suitable for mating with a PCO
1881 bottle finish was employed. Prior to testing, the tamper
evident band (10*) was unfolded and then almost entirely removed,
by cutting through the tamper evident band at a distance of
approximately 2 mm from each end of the tether proxy section. The
remaining portion of the tamper evident band (as shown in FIGS. 11A
and 11B) then, includes the tether proxy section having an arcuate
length of 6 mm, and a further 2 mm arcuate length section on either
side of the tether proxy section, all of which has a cross
sectional width of 0.6 mm. Adding 2 mm to either side of the tether
proxy section provides a larger surface area to grip when carrying
out the shear deformation testing. In order to support the closure
for testing in the Torque Tester unit, a modified tubular preform
was used (item 45 in FIG. 11B). The tubular pre-form 45 was made of
polyethylene terephthalate and was modified to have smooth outer
walls. Following this, a brass rod (50), having a diameter which
fit snuggly within the preform (45) was inserted as a plug to
afford rigidity to the pre-form and to prevent its deformation
during testing. Next, the closure was placed on top of the pre-form
and the remaining section of the tamper evident band (10*) was
clamped to the preform using vice grips. The closure and preform
were then mounted within the Torque Tester. The cap portion (1) was
gripped from above within a suitably designed chuck and rotated at
a removal torque speed of 0.8 rpm, relative to the clamped section
of the tamper evident band, using the Torque Tester. The shear
strength of the tether proxy (40) is defined as the maximum torque
(in inches.pounds) required to separate the cap portion (1) from
the remaining section of the tamper evident band section (10*) by
breaking the tether proxy (40). The reported shear strength in
Table 5 is the average of at least 5 such shear deformation
tests.
Tear Deformation of a Tether Proxy
[0192] A TMS 5000 Torque Tester unit manufactured by Steinfurth was
used to carry out the tether proxy shear deformation testing. The
unit was adjusted to operate in "removal torque mode". A closure
having a tether proxy section (area 40 in FIGS. 10A and 10B) with a
6 mm arcuate length and a 0.6 mm cross-sectional width connecting a
cap portion (1) to a tamper evident band 10* (a proxy for a
retaining means portion, 10) and suitable for mating with a PCO
1881 bottle finish was employed. In order to support the closure
for testing in the Torque Tester unit, a modified tubular pre-form
was used (item 45 in FIG. 11C). The tubular pre-form 45 was made of
polyethylene terephthalate and was modified to have smooth outer
walls. Following this, a brass rod (50), having a diameter which
fit snuggly within the pre-form (45) was inserted as a plug to
afford rigidity to the pre-form and to prevent its deformation
during testing. Next, the closure was placed on top of the preform.
Prior to testing, the tamper evident band (10*) was deflected
downward (on the opposite side of the tether proxy section) and
away from the cap portion (1) as is shown in FIG. 11C. The downward
deflection breaks all the narrow pin sections (the frangible line 9
in FIGS. 10A and 10B) joining the top edge of the tamper evident
band to the lower edge of the cap portion while leaving the larger
continuous section, the tether proxy section (40), intact. The
tamper evident band (10*) is deflected downward and away from the
cap portion (1) until the top edge of the tamper evident band makes
an angle with the lower edge of the cap portion of about 27
degrees, while the tether portion remains intact along its 6 mm
arcuate length (see FIG. 11C). The tamper evident band (10*) was
then clamped to the pre-form in this downwardly deflected position
using vice grips. The closure and pre-form were then mounted within
the Torque Tester. The cap portion (1) was gripped from above
within a suitably designed chuck and rotated at a removal torque
speed of 0.8 rpm, relative to the clamped tamper evident band
(10*), using the Torque Tester. The tear strength of the tether
proxy (40) is defined as the maximum torque (in inches.pounds)
required to separate the cap portion (1) from the downwardly
deflected tamper evident band (10*) by breaking the tether proxy
(40). The reported tear strength in Table 5 is the average of at
least 5 such tear deformation tests.
Tensile Deformation of a Tether Proxy
[0193] Tensile deformation tests were performed using a tensile
machine (an Instron 4204 universal tester, with a 1 KN (225 lbf)
capacity load cell) with the crosshead velocity set at 50 mm/min. A
closure having a tether proxy section (area 40 in FIGS. 10A and
10B) with a 6 mm arcuate length and a 0.6 mm cross-sectional width
connecting a cap portion (1) to a tamper evident band 10* (a proxy
for a retaining means portion, 10) and suitable for mating with a
PCO 1881 bottle finish was employed. Prior to testing, the tamper
evident band (10*) was unfolded and then almost entirely removed,
by cutting through the tamper evident band at a distance of
approximately 2 mm from each end of the tether proxy section (see
FIGS. 11A, 12A and 12B). The remaining portion of the tamper
evident band (as shown in FIGS. 11A, 12A and 12B) then, includes
the tether proxy section having an arcuate length of 6 mm, and a
further 2 mm arcuate length section on either side of the tether
proxy section, all of which has a cross sectional width of 0.6 mm.
Adding 2 mm to either side of the tether proxy section provides a
larger surface area to grip when carrying out the tensile
deformation testing. For the tensile deformation test, most of the
cap portion (1) was similarly cut away, leaving only a section of
the cap portion side wall connected to the what was left of the
tamper evident band (see FIGS. 12A and 12B). This "cut away"
section of the closure was then mounted in the tensile tester, with
the remaining cap portion side wall and the remaining tamper
evident band each being secured with 0.5-inch wide steel serrated
grips at a 0.25-inch grip separation. During the tensile testing,
the remaining section of the cap portion (1) and the remaining
section of the tamper evident band (10*) were drawn apart
vertically. The tensile strength of the tether proxy (40) is
defined as the maximum load (in grams.force, gf) required to
separate the remaining cap portion (1) from the remaining tamper
evident band section (10*) by breaking the tether proxy (40). The
reported tensile strength in Table 5 is the average of at least 5
such tensile deformation tests.
TABLE-US-00005 TABLE 5 Average Shear, Tear and Tensile Deformation
of a Tether Proxy Closure Type No. 2 1 (Comparative) Shear Strength
11.96 9.43 (inches pounds) Tear Strength 11.56 9.18 (inches pounds)
Tensile Strength 16448 12800 (grams force)
[0194] A person skilled in the art will recognize from the data
provided in Table 5, that a tether proxy made using a polyethylene
copolymer according to the current disclosure may have a relatively
good ability to resist shear, tear and tensile deformations
(relative to a comparative tether proxy made from a unimodal
polyethylene copolymer of ethylene and 1-butene, SCLAIR.RTM. 2712).
The data thus provides further evidence that the polyethylene
copolymers described herein may be useful in the production of
bottle closure assemblies, by preventing facile separation of a cap
portion from a retaining means portion or from a bottle, and by
generally helping to prevent loss or disassociation of a cap
portion (a potential plastic waste stream) from a bottle, where the
cap portion could otherwise contribute to environmental waste
concerns.
[0195] The present disclosure has been described with reference to
certain details of particular embodiments thereof. It is not
intended that such details be regarded as limitations upon the
scope of the disclosure except insofar as and to the extent that
they are included in the accompanying claims.
* * * * *