Note: Descriptions are shown in the official language in which they were submitted.
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PREFORM EXTENDED FINISH FOR PROCESSING LIGHT WEIGHT
ECOLOGICALLY BENEFICIAL BOTTLES
PRIORITY
[0001] This application is a continuation in part of, and claims the
benefit of, U.S. Patent
Application Serial No. 15/013,141, entitled "Prefoiin Extended Finish For
Processing Light
Weight Ecologically Beneficial Bottles," filed February 2, 2016, which is a
continuation in part
of, and claims the benefit of, U.S. Patent Application Serial No. 14/590,705,
filed January 6, 2015,
which is a continuation of, and claims the benefit of, U.S. Patent Application
Serial No.
13/295,699, filed on November 14, 2011, which claims benefit to U.S.
Provisional Patent
Application Serial No. 61/413,167, filed November 12, 2010. Each of the
aforementioned
applications is incorporated by reference in its entirety into this
application.
FIELD
[0002] The field of the present disclosure generally relates to plastic
bottles and preforms.
More particularly, the field of the present disclosure relates to plastic
perfolins and bottles blown
from such preforms that are suitable for containing beverages and utilize less
resin such that they
are lighter in weight than conventional bottles.
BACKGROUND
[0003] Plastic containers have been used as a replacement for glass or
metal containers in the
packaging of beverages for several decades. The most common plastic used in
making beverage
containers today is polyethylene terephthalate (PET). Containers made of PET
are transparent,
thin walled, and have the ability to maintain their shape by withstanding the
force exerted on the
walls of the container by their contents. PET resins are also reasonably
priced and easy to process.
PET bottles are generally made by a process that includes the blow-molding of
plastic prefoims
which have been made by injection molding of the PET resin.
[0004] Advantages of plastic packaging include lighter weight and decreased
breakage as
compared to glass, and lower costs overall when taking both production and
transportation into
account. Although plastic packaging is lighter in weight than glass, there is
still great interest in
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creating the lightest possible plastic packaging so as to maximize the cost
savings in both
transportation and manufacturing by making and using containers that contain
less plastic.
SUMMARY
[0005] A new approach which relies on a general change in preform design
has been invented,
which significantly improves the ability to blow efficient, lightweight
bottles. The design
elegantly incorporates features for protecting critical dimensions of the
bottle and stabilizing the
production blowing process. These features may also utilize less resin while
achieving suitable
mechanical performance resulting in a reduction in the use of petroleum
products by the industry.
[0006] In accordance with embodiments disclosed herein, there is provided a
plastic preform
suitable for forming a bottle, and a bottle or container made from such a
preform. The preform
comprises a neck portion adapted to engage a closure and including a support
ring at its lowermost
point, the neck portion having a first wall thickness, and an elongated body
portion including a
generally cylindrical wall portion and an end cap. In some embodiments, the
upper segment of
the body portion adjacent to the support ring has a second wall thickness
substantially similar to
the first wall thickness and less than a third wall thickness in a lower
segment of the body portion.
Further embodiments may include one or more of the following features: the
second wall thickness
is about 25% to about 40% of the third wall thickness; the second wall
thickness is about 25% to
about 30% of the third wall thickness; the second wall thickness is about 0.7
mm to about 0.8 mm;
an axial length of the upper segment is about 25% or more of an axial length
of the neck portion;
and/or an axial length of the upper segment is about 25% to about 35% of an
axial length of the
neck portion. In other embodiments, the second wall thickness is thicker or
thinner than the first
wall thickness by 0.1 mm, 0.2 mm, 0.3 mm, or 0.4 mm. Containers or bottles
made from such
preforms are also disclosed herein.
[0007] In accordance with embodiments disclosed herein, there is provided a
plastic prefoim,
comprising a neck portion often including a support ring, wherein the neck
portion has a first wall
thickness, and a body portion including an elongated cylindrical wall having
upper, middle and
lower segments, wherein the middle segment has a second wall thickness and the
lower segment
of the body portion includes an end cap. In some embodiments, the upper
segment of the body
portion has a wall thickness substantially similar to the first wall thickness
and less than the second
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wall thickness and/or the axial length of the upper segment is about 25% or
more of the axial length
of the neck portion. Further embodiments may include one or more of the
following features: the
upper segment wall thickness is about 25% to about 40% of the second wall
thickness; the upper
segment wall thickness is about 25% to about 30% of the second wall thickness;
the upper segment
wall thickness is about 0.7 mm to about 0.8 mm; and/or an axial length of the
upper segment is
about 25% to about 35% of an axial length of the neck portion. In other
embodiments, the upper
segment wall thickness is thicker or thinner than the first wall thickness by
0.1 mm, 0.2 mm, 0.3
mm, or 0.4 mm. Containers or bottles made from such preforms are also
disclosed herein.
[0008] In an exemplary embodiment, a preform suitable for being blow-molded
to form a
container comprises a neck portion comprising an opening to an interior of the
preform; a tapered
portion comprising a smooth transition from a diameter of the neck portion to
a smaller diameter
of a cylindrical portion comprising an elongate member that extends to an end
cap; and a finish
disposed on the neck portion and configured to threadably receive a cap.
[0009] In another exemplary embodiment, the tapered portion comprises a
wall thickness that
smoothly transitions from a wall thickness of the neck portion to a relatively
greater wall thickness
of the cylindrical portion, the wall thickness of the tapered portion and the
wall thickness of the
cylindrical portion being suitable for being blow-molded into a predetermined
shape and size of
the container.
[0010] In another exemplary embodiment, the finish comprises one or more
threads configured
to rotatably engage with threads disposed within the cap. In another exemplary
embodiment, the
one or more threads each extends along a section of the circumference of the
neck portion. In
another exemplary embodiment, the one or more threads are spaced uniformly
around the
circumference of the neck portion. In another exemplary embodiment, adjacent
of the one or more
threads share an intervening valley configured to allow passage of a thread
disposed in the cap.
[0011] In another exemplary embodiment, the neck portion comprises a
plurality of internal
columns disposed within the opening and configured to impart a degree of
structural integrity to
the neck portion and reduce an amount of material comprising the preform. In
another exemplary
embodiment, the plurality of internal columns comprises three internal columns
that are positioned
at substantially 120-degree intervals around the circumference of the neck
portion.
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[0012] In another exemplary embodiment, the neck portion comprises one or
more exterior
columns configured to maintain a necessary degree of structural integrity of
the prefoun and reduce
the amount of material comprising the preform. In another exemplary
embodiment, the one or
more exterior columns are disposed uniformly around the perimeter of the neck
portion, each of
the exterior columns comprising a vertically aligned thicker region of the
neck portion. In another
exemplary embodiment, the one or more exterior columns are positioned in
locations around the
perimeter of the neck portion that coincide with the locations of internal
columns within the
opening of the neck portion. In another exemplary embodiment, the one or more
exterior columns
are positioned at specific intervals between the locations of internal columns
within the opening
of the neck portion. In another exemplary embodiment, adjacent exterior and
interior columns are
separated by 60-degree intervals around the circumference of the neck portion.
[0013] In another exemplary embodiment, the neck portion comprises a bevel
disposed at a
beginning of the opening and configured to enter into sliding contact with a
sealing flange of the
cap, the bevel being configured to compress the sealing flange to a
predetettnined degree, thereby
fainting a tight seal suitable to retain pressurized contents within the
container.
[0014] In an exemplary embodiment, a prefotin suitable for being blow-
molded to faun a
container comprises a neck portion comprising an opening to an interior of the
preforni; a body
portion comprising a tapered portion that smoothly transitions from the neck
portion to a
cylindrical portion and an end cap, the body portion comprising a wall
thickness suitable for being
blow-molded into a desired shape and size of the container; a finish disposed
on the neck portion
and configured to threadably receive a cap; a plurality of internal columns
disposed within the
opening; one or more exterior columns disposed around the perimeter of the
neck portion; and a
bevel disposed at a beginning of the opening and configured to receive a
sealing flange of the cap.
[0015] In another exemplary embodiment, the plurality of internal columns
and the one or
more exterior columns are configured to maintain a degree of structural
integrity of the neck
portion and reduce the amount of material required to foini the prefoim. In
another exemplary
embodiment, the tapered portion comprises a smooth transition from a diameter
and a wall
thickness of the neck portion to a relatively smaller diameter and a greater
wall thickness of the
cylindrical portion.
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[0016] In another exemplary embodiment, the finish comprises at least three
threads
configured to rotatably engage with threads disposed within the cap, and
wherein an intervening
valley is disposed between adjacent of the at least three threads and
configured to allow passage
of a thread disposed in the cap. In another exemplary embodiment, each of the
at least three threads
extends along a section of the circumference of the neck portion. In another
exemplary
embodiment, the section comprises substantially 144-degrees of the
circumference. In another
exemplary embodiment, the at least three threads are spaced unifomily around
the circumference
of the neck portion.
[0017] In an exemplary embodiment, a PET preform for fanning a heat-set
container
comprises: a cylindrical portion configured to be blow-molded into the heat-
set container; and a
neck portion that couples a finish with the cylindrical portion.
[0018] In another exemplary embodiment, the neck portion tapers from the
finish to a diameter
of the cylindrical portion. In another exemplary embodiment, a wall thickness
of the neck portion
smoothly transitions to a predetermined wall thickness of the cylindrical
portion. In another
exemplary embodiment, the predetemiined wall thickness is suitable for being
blow-molded into
the heat-set container. In another exemplary embodiment, the predeteimined
wall thickness is
configured for being blow-molded into a heat-set container suitable for
containing pressurized
contents. In another exemplary embodiment, the predeteimined wall thickness is
selected such
that the heat-set container may be configured to withstand nitrogen hot-
filling with pressurized
contents.
[0019] In another exemplary embodiment, the finish includes an opening to
an interior of the
cylindrical portion. In another exemplary embodiment, the finish is configured
to accommodate a
relatively large headspace suitable for nitrogen hot-filling the heat-set
container with pressurized
contents. In another exemplary embodiment, the finish includes at least one
thread configured to
rotatably engage with threads disposed in a cap. In another exemplary
embodiment, the opening
includes a bevel configured to receive a sealing flange disposed in a cap so
as to form a seal suitable
to retain pressurized contents within the heat-set container. In another
exemplary embodiment,
the at least one thread extends along a section of the circumference of the
finish. In another
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exemplary embodiment, the at last one thread includes three threads that are
unifoinily spaced
around the circumference of the finish.
[0020] In an exemplary embodiment, a PET preform for forming a heat-set
container
comprises: a cylindrical portion configured to be blow-molded into the heat-
set container; a neck
portion coupled with the cylindrical portion; and a finish disposed on the
neck portion and
including an opening to an interior of the cylindrical portion.
[0021] In another exemplary embodiment, the cylindrical portion includes a
wall thickness
that is suitable for being blow-molded into a heat-set container capable of
withstanding nitrogen
hot-filling of the container with pressurized contents.
[0022] In another exemplary embodiment, the neck portion tapers from a
diameter of the finish
to a diameter of the cylindrical portion. In another exemplary embodiment, a
wall thickness of the
neck portion transitions to a predetermined wall thickness of the cylindrical
portion. In another
exemplary embodiment, the predeteimined wall thickness is suitable for blow-
molding at least the
cylindrical portion into a heat-set container capable of withstanding nitrogen
hot-filling the heat-
set container with pressurized contents.
[0023] In another exemplary embodiment, the finish is configured to receive
a container cap
so as to retain pressurized contents within the heat-set container. In another
exemplary
embodiment, at least one thread is circumferentially disposed on the finish
and configured to
rotatably engage with threads disposed in the container cap. In another
exemplary embodiment,
the finish is configured to accommodate a headspace suitable for nitrogen hot-
filling the heat-set
container with pressurized contents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The drawings refer to embodiments of the present disclosure in
which:
[0025] Figure 1 illustrates a side plan view of an exemplary embodiment of
a preform suitable
for being blow-molded to folin a bottle, according to the present disclosure;
[0026] Figure 2A illustrates a cross-sectional view of an exemplary
prefolin without an
extended lightweight finish;
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[0027] Figure 2B illustrates a cross-sectional view of another exemplary
preform without an
extended lightweight finish;
[0028] Figure 2C illustrates a cross-sectional view of an exemplary
embodiment of a preform
in accordance with the present disclosure;
[0029] Figure 3 illustrates a cross-sectional view of a prefonn in the
cavity of a blow-molding
apparatus of the type that may be used to make a bottle or container,
according to the present
disclosure;
[0030] Figure 4 illustrates a side plan view of an exemplary embodiment of
a bottle or
container that has been blow-molded by way of the apparatus illustrated in
Fig. 3, according to the
present disclosure;
[0031] Figure5A illustrates a micro-CT slice of a neck and upper body of an
exemplary
preform as illustrated in Fig. 2A;
[0032] Figure 5B illustrates a micro-CT slice of the neck and upper body of
an exemplary
embodiment of a preform as is illustrated in Fig. 2C, in accordance with the
present disclosure;
[0033] Figure 6 illustrates a superimposition of micro-CT slices of an
exemplary preform as
illustrated in Fig. 5B and a bottle blown therefrom;
[0034] Figure 7A illustrates a side plan view of an exemplary embodiment of
a prefoim
suitable for being blow-molded to form a bottle in accordance with the present
disclosure;
[0035] Figure 7B illustrates a cross-sectional view of the preform
illustrated in Fig. 7A, taken
along a line 7B-7B, according to the present disclosure;
[0036] Figure 7C illustrates a cross-sectional view of the preform
illustrated in Fig. 7A, taken
along a line 7C-7C in accordance with the present disclosure;
[0037] Figure 8A illustrates a side plan view of an exemplary embodiment of
a neck portion
suitable for being incorporated into a preform, such as illustrated in Fig.
7A, in accordance with
the present disclosure;
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[0038] Figure 8B illustrates a cross-sectional view of the exemplary neck
portion illustrated in
Fig. 8A, taken along a line 8B-8B, according to the present disclosure;
[0039] Figure 8C illustrates a close up, detail view of a portion of the
cross-sectional view
illustrated in Fig. 8B, in accordance with the present disclosure;
[0040] Figure 9A illustrates a cross-sectional view of the exemplary neck
portion illustrated
in Fig. 8A, taken along a line 9A-9A, in accordance with the present
disclosure;
[0041] Figure 9B illustrates a close up, detail view of a cross-sectional
profile of threads
illustrated in Fig. 9A, in accordance with the present disclosure;
[0042] Figure 9C illustrates a close up, detail view of a cross-sectional
profile of a neck ring
illustrated in Fig. 9A, according to the present disclosure; and
[0043] Figure 9D illustrates a close up, detail view of a cross-sectional
profile of a support
ring illustrated in Fig. 9A, in accordance with the present disclosure.
[0044] While the present disclosure is subject to various modifications and
alternative forms,
specific embodiments thereof have been shown by way of example in the drawings
and will herein
be described in detail. The invention should be understood to not be limited
to the particular forms
disclosed, but on the contrary, the intention is to cover all modifications,
equivalents, and
alternatives falling within the spirit and scope of the present disclosure.
DETAILED DESCRIPTION
[0045] In the following description, numerous specific details are set
forth in order to provide
a thorough understanding of the present disclosure. It will be apparent,
however, to one of ordinary
skill in the art that the invention disclosed herein may be practiced without
these specific details.
In other instances, specific numeric references such as "first prefoim," may
be made. However,
the specific numeric reference should not be interpreted as a literal
sequential order but rather
interpreted that the "first preform" is different than a "second prefoint."
Thus, the specific details
set forth are merely exemplary. The specific details may be varied from and
still be contemplated
to be within the spirit and scope of the present disclosure. The term
"coupled" is defined as
meaning connected either directly to the component or indirectly to the
component through another
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component. Further, as used herein, the terms "about," "approximately," or
"substantially" for
any numerical values or ranges indicate a suitable dimensional tolerance that
allows the part or
collection of components to function for its intended purpose as described
herein.
[0046] Disclosed herein are articles, including preforms and containers,
which utilize less
plastic in their construction while maintaining the ease of processing and
excellent structural
properties associated with current commercial designs.
[0047] Figure 1 illustrates a side plan view of an exemplary embodiment of
a prefoitn 30
suitable for being blow-molded to form a bottle, according to the present
disclosure. The prefotm
is preferably made of material approved for contact with food and beverages
such as virgin PET
and can be of any of a wide variety of shapes and sizes. The preform shown in
Fig. 1 is of the type
which will faun a 12-16 oz. beverage bottle, but as will be understood by
those skilled in the art,
other preform configurations may be used depending upon the desired
configuration,
characteristics and use of the final article. The prefoun 30 may be made by
injection molding
methods including those that are well known in the art.
[0048] Figure 2A illustrates a cross-sectional view of an exemplary prefoun
30. The prefonn
30 has a neck portion 32 and a body portion 34, fonned monolithically (i.e.,
as a single, or unitary,
structure). Advantageously, the monolithic arrangement of the prefottn, when
blow-molded into
a bottle, provides greater dimensional stability and improved physical
properties in comparison to
a prefoun constructed of separate neck and body portions, which are bonded
together.
[0049] The neck portion 32 begins at an opening 36 to an interior of the
prefoun 30 and extends
to and includes a support ring 38. The neck portion 32 is further
characterized by the presence of
a structure for engaging a closure. In the illustrated embodiment, the
structure includes threads
40, which provide a means to fasten a cap to the bottle produced from the
preform 30. The
illustrated preform has a shorter overall neck area than most conventional
prefouns, which shorter
neck area may also be thinner than in conventional prefouns. The thickness of
the neck area 52A
is measured at the very top or between the threads or any other protruding
structures.
[0050] The body portion 34 comprises an elongated structure extending down
from the neck
portion 32 and culminating in an end cap 42. In some embodiments the body
portion 34 may be
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generally cylindrical, and the end cap 42 may be conical or frustoconical and
may also be
hemispherical, and the very terminus of the end cap may be flattened or
rounded. The preform
wall thickness 44 through most of the body portion 34 will depend upon the
overall size of the
preform 30 and the wall thickness and overall size of the resulting container.
The preform wall
thickness between 48A and 50A is slightly thinner than the wall thickness
throughout the straight
portion of the body portion, both of which are thicker than at 46A immediately
below the support
ring 38. A slight taper often below 0.01 mm may also be found from 50A to 44
to help with release
of the injected preform from the core during processing.
[0051] Figure 2B illustrates a cross-section of another embodiment of a
prior art preform 30.
The preform 30 has a neck portion 32 and a body portion 34. The neck portion
32 of the preform
is of an axial length as may be found in conventional preforms. Although the
thickness of the
upper segment or portion of the body portion 46B is of a similar thickness as
the neck portion 52B,
it is also substantially similar thickness or the same thickness as the
remainder of the body portion
of the preform (e.g. 44B, 50B). In contrast to the preform 30 illustrated in
Fig. 2B, the preform
illustrated in Fig. 2C is substantially thicker in the middle segment (e.g.
44C) of the body and in
the end cap 42 than in the upper segment (e.g. 46C) of the body portion, which
is of a similar
thickness or same thickness as the neck portion 52C. In other embodiments, the
upper segment of
the body portion (e.g. 46C) may be thinner than the neck portion 52C.
[0052] In contrast to the preform illustrated in Fig. 2A, the preform 30
illustrated in Fig. 2C
has a reduced thickness in the upper portion of the body portion 34 of the
preform below the
support ring 38, in that point 46C is substantially thinner than the
corresponding location 46A in
the prior art preform, 48C is of similar thickness to 46C which is much
thinner than 48A of the
prior art preform, and the thickness increases from point 48C to 50C, at which
point the body
portion 34 transitions into the straight portion of the preform having the
thickness 44C. Preforms
and containers blown from such preforms having such a thinned area at the
uppermost portion of
the body portion are sometimes referred to herein as having an "extended
finish." A further
illustration of this difference, in accordance with one embodiment, can be
seen in Fig. 5B and Fig.
6. Further, the prefoim 30 illustrated in Fig. 2C also has a shorter overall
neck area than most
conventional preforms. As will be appreciated, the shorter neck area may also
be thinner than in
conventional preforms.
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[0053] As compared to the prior art preform in Fig. 2A, the thickness at
46C is about 20-50%
of the thickness at 46A, the thickness at 48C is about 20-60% of the thickness
at 48A, and the
thickness at 50C is about 80-100% of the thickness at 50A. In one embodiment,
the thicknesses
of 46C and 48C differ by less than about 20%, including less than about 10%,
or they are
substantially the same thickness. As an example, for a preform used to fomi an
8 oz. bottle, the
thickness at 46C is about 0.7 mm, the thickness at 48C is about 0.8, and the
thickness at 50C is
about 2 mm. By means of comparison, for the prior art preform used to faun an
8 oz. bottle, the
thickness at 46A is about 1.5 mm the thickness at 48A is about 2 mm, and the
thickness at 50A is
about 2.5 mm. As another example, for a preform used to foim a 16.9 oz.
bottle, the thickness at
46C is about 0.7 mm, the thickness at 48C is about 1 mm, and the thickness at
50C is about 2.4
mm, compared to about 1.2 mm at 46A, about 1.8 mm at 48A, and about 2.4 mm at
50A in a prior
art preform. As another example, for a preform used to fottn a 33.8 oz.
bottle, the thickness at 46C
is about 0.75 mm, the thickness at 48C is about 1 mm, and the thickness at 50C
is about 2.6 mm,
compared to about 1.5 mm at 46A, about 1.9 mm at 48A, and about 2.7 mm at 50A
in a prior art
preform. The total weight of a preform used to form an 8 oz. bottle according
to Fig. 2C is about
7 grams as compared to about 12.5 grams for a preform according to Fig. 2A.
The total weight of
a preform used to farm a 16.9 oz. bottle according to Fig. 2C is about 8.5
grams as compared to
about 9.2 grams for a prefolln according to Fig. 2A. The total weight of a
prefomi used to faun a
33.8 oz. bottle according to Fig. 2C is about 18.3 grams as compared to about
26 grams for a
prefoim according to Fig. 2A. Using the information provided herein, one
skilled in the art can
prepare other sizes of prefomis that have similar characteristics to those
described herein. Also,
the dimensions in other useful embodiments of prefomis may vary from the above-
stated
dimensions by between substantially 0.1 mm and substantially 1 mm, inclusive.
[0054] In accordance with certain embodiments, the upper segment of the
body portion of the
preform, which is adjacent to the support ring, has a thickness that is
substantially similar to the
thickness 52C of the neck portion 32. In some such embodiments, the
thicknesses of the upper
segment and the neck portion 32 may differ by +/- 0 mm, 0.1 mm, 0.2 mm, 0.3
mm, or 0.4 mm.
In some such embodiments, the thicknesses of the upper segment and the neck
may differ by up
to 10%, up to 20%, or up to 30%. Accordingly, the thickness of the upper
segment of the body
portion of the preform may be substantially the same thickness, or it may be
either thicker or
thinner than the neck portion 52C. In accordance with other embodiments, the
thickness of the
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upper segment of the body portion 34 of the preform is less than that of a
middle or lower segment
of the body portion. In some such embodiments, the wall thickness of the upper
section is about
10% to about 40% of the thickness of the lower and/or middle section of the
body, including about
15% to about 40%, about 15% to about 30%, about 25% to about 35%, about 20% to
about 35%,
about 20% to about 30%, including about 12%, about 13%, about 17%, about 19%,
about 22%,
about 24%, about 27%, about 29%, about 31%, and about 33%, including ranges
bordered and
including the foregoing values. In some such embodiments, the wall thickness
of the upper
segment of the body is about 0.3 mm to about 0.9 mm, including about 0.3 mm to
about 0.5 mm,
about 0.4 mm to about 0.7 mm, about 0.5 mm to about 0.9 mm, about 0.7 mm to
about 0.8 mm,
including about 0.35 mm, about 0.45 mm, about 0.55 mm, about 0.65 mm, about
0.75 mm, and
about 0.85 mm, including ranges bordered and including the foregoing values.
In accordance with
other embodiments, the axial length of the upper segment measures about 20% or
more, including
about 25% or more of the axial length of the neck portion, including about 20%
to about 30%,
about 20% to about 35%, about 25% to about 30%, and about 25% to about 35% of
the axial length
of the neck portion. Preforms may include one or more or all of the features
described above.
[0055] After a prefotm, such as that depicted in Figs. 2A, 2B and 2C, is
prepared by injection
molding, the preform is subjected to a stretch blow-molding process. Referring
to Fig. 3, in this
process a preform 50 is placed in a mold 80 having a cavity corresponding to a
desired container
shape. The prefotm 50 is then heated and expanded by stretching such as by a
stretch rod inserted
into the center of the prefoun to push it to the end of the mold and by air
forced into the interior
of the preform 50 to fill the cavity within the mold 80, creating a container
82. The blow-molding
operation normally is restricted to the body portion 34 of the preform with
the neck portion 32,
including the support ring 38, retaining the original configuration as in the
preform.
[0056] When performing the stretch blow-molding process to create the
container, preforms
are conventionally loaded onto a spindle which engages the inner wall of the
neck portion of the
preform and facilitates transporting the preform into and through the stretch
blow-molding
machinery. Because of the extended neck finish in accordance with embodiments
described
herein, it may be beneficial to have the spindle extend into the inner wall of
the preform into the
region of the upper segment of the body portion, beyond the neck portion. In
some embodiments,
the spindle loads into the preform the full extent of the extended neck
finish. This may be
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accomplished by adjusting the depth to which the spindle loads and/or by
changing the spindle to
have sufficient length to extend the greater distance. The extended spindle
loading depth helps to
maintain the dimensions of the extended neck finish, especially in those
embodiments where the
extended neck finish is relatively thin such that the dimensional stability of
the lower part of the
extended neck finish and/or the lower part of the upper segment of the body
portion would
otherwise be at risk due to exposure to heating elements and/or elevated
temperatures in other
portions of the body during the stretch blow-molding process.
[0057] Figure 4 illustrates a side plan view of an exemplary embodiment of
a container 82 that
may be made by way of blow-molding the preform 50 of Fig. 3, or the preforms
30 illustrated in
Figs. 2A, 2B and 2C. The container 82 has a neck portion 32 and a body portion
34 corresponding
to the neck and body portions of the preforms 30 illustrated in Figs. 2A, 2B
and 2C. The neck
portion 32 is further characterized by the presence of threads 40 or other
closure engagement
means that provides a way to fasten a cap onto the container 82.
[0058] In preforms having neck finishes that are lighter in weight and
portions immediately
below the finish (uppermost portion of the body), such as those described
herein, the lighter weight
portions are more susceptible to damage or softening from the heat supplied to
the remainder of
the preform during blow-molding. Aggressive cooling of the finish was seen as
a way to enable
light weighting. Since not all machines cool identically or as effectively, it
was observed that to
properly blow the bottle, the finish would go through distortion. A short term
solution to prevent
distorting the finish was to limit heating of the preform below the support
ring 38. This left plastic
from the preform in the neck of the bottle. This is referred to as a "ring" in
the neck. While
unattractive and inefficient from a resin use perspective, such a decision
allowed the light weight
preform to continue to produce acceptable bottles.
[0059] Thus, a concept was conceived where the material normally placed in
the preform to
be stretched from directly below the support ring was removed and replaced
with a wall thickness
at the desired dimensions of the finished product. The distance of this bottle
"neck" was set by
the bottle design, but the new extended finish concept allows for some heating
and stretching. By
definition the design change also provides for a transition from fully blown
bottle to rigidly
retained threads across this zone. An extended finish is especially useful in
smaller finishes that
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are substantially shorter from the support ring to the top of the finish as
compared to prior finishes
that have considerable distance (up to 10 mm) from the threads to the base of
the support ring.
Such shorter finishes may also be thinner. This new design was also
discouraged because having
a thin area upstream of a thicker threaded area in an injection mold would be
difficult, if not
impossible, to mold properly since it would likely prevent resin from
completely filling the neck
finish under usual injection pressures. Thus injection limitations have
historically limited this
approach rather than mechanical perfoiniance. Accordingly, in some
embodiments, during the
injection molding process, the closing of the neck ring can be slightly
delayed to allow filling of
the small spaces before clamping it down to mold at least the neck and finish.
Minimal
experimentation is needed to determine the correct timing and amount of
polymer melt to ensure
complete filling of the neck and finish while minimizing flashing.
[0060] In addition to providing lighter weight preforms and bottles, the
extended finish
preforms disclosed herein, which may incorporate other lightweighting features
described herein
such as a shorter and/or thinner neck and/or thinner walls in the body
portion, can also have the
advantage of being produced using a lower cycle time in molding. Lower cycle
time increases the
number of preforms that can be made by a single piece of equipment in a day
and can lower the
total energy needed to produce a single preform, resulting in additional cost
savings to the
manufacturer.
[0061] It was also generally thought that a thicker support ring and larger
amounts of plastic
near that region (above in the finish and below at the uppermost portion of
the body) was needed
to absorb heat and prevent it from transferring into the finish. This has also
been shown by the
present applicant to be incorrect. It has been found that the thick ring of
plastic provides heat
storage and serves as a heat source during later bottle handling and
processing steps. Thinning the
region below the support ring, under this new perspective, provides resistance
to heat travelling up
to the finish in that this area can rapidly cool so that it is not a latent
heat source during later
operations. Since, in certain embodiments, this region does not need to be
stretched during blow-
molding, it does not need to be heated and the blow-molding procedure and
apparatus may be
adjusted such that the uppermost portion or upper segment of the
preform/container body (in the
area of the extended finish) is not heated, or heated very little as compared
to the bulk of the body
of the preform, as part the blow-molding process. This change is easy to
accommodate in modem
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equipment and makes the production process easier and more stable. For
example, the position of
the cooling rail or shims may be adjusted to provide greater protection from
heat for the extended
finish, the intensity of the heating element(s) may be adjusted, and/or the
position of the heating
element(s) may be adjusted. It should be noted that preforms having an
extended finish may be
blow-molded in conventional processes that actively heat the lower portion of
the extended finish
(i.e. the uppermost portion of the body), but such processes are generally
less effective in creating
consistently stable bottles during production.
[0062] The applicant has discovered that when the preform of Fig. 2A is
blown to farm a bottle
in a process that protects the extended finish from heating during blow-
molding as described
above, the thickness at 46A and 48A changes very little, with essentially all
of the wall portion of
the bottle being formed from the stretching of the wall around 50A and below.
This is shown in
Fig. 6 which presents a superimposition of cross-sections of a preform having
an extended finish
and a bottle blown therefrom. Accordingly, the wall thickness at the lower
segment of the neck
portion of the prefolin, including at 46C and 48C, is lessened as described
hereinabove to reduce
the amount of material needed to form the preform while still maintaining the
necessary degree of
structural integrity to allow for ease in blow-molding to fonti a container
that has sufficient
mechanical strength to withstand the forces exerted on it during formation,
filling, transportation
and use.
[0063] In accordance with some embodiments herein, the width of the support
ring may be
increased as compared to that in a standard shorter finish. Given that a 0.6
mm width to the support
ring (as in a standard shorter finish) provides forces upon a finger that are
considered to be within
the pain threshold for a finger, increasing the width may provide greater
comfort for the consumer.
Accordingly, a width of at least about 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2
mm, 2.2 mm,
2.4 mm, 2.6 mm or greater would provide greater comfort to the consumer when
opening the
closure. Alternatively or concomitantly, changes may be made to the cap
including by increasing
the apparent cap diameter such as by providing ribs on the tamper ring that
are of greater height
than the remaining cap. Other reasons to widen the ring include conveyor
handling, heat sink
properties of the ring, better feel when opening the container, greater
resistance to damage during
processing and transport. It should be noted that increasing the width of the
support ring is counter
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to lightweighting, such that it should be balanced with other considerations
when designing a
preform and container.
[0064] In some embodiments, in which it is desired for the container to be
heat-set, it is
preferred that the containers be blow-molded in accordance with processes
generally known for
heat set blow-molding, including, but not limited to, those which involve
orienting and heating in
the mold, and those which involve steps of blowing, relaxing and reblowing.
The mold 80 can
quickly cool the container during this process, especially with high heat
transfer material absorbing
heat from the container at a high rate.
[0065] In some embodiments, the blow-mold may be used to produce
crystalline neck finishes.
For example, the neck portion of the blow-mold and the body portion of the
blow-mold can
selectively control the temperature of the preform/container to achieve a
desired amount of
crystallization. Thus, the neck portion of the preform/container can be heated
and gradually
reduced in temperature to produce a desired amount of crystalline material.
[0066] In some embodiments, a PET preform may be configured for forming a
heat-set
container, such as by way of blow-molding the prefoun in accordance with
processes generally
known for heat-set blow-molding. The PET prefotm may be comprised of a
cylindrical portion
configured to be blow-molded into the heat-set container capable of
withstanding being nitrogen
hot-filled with pressurized contents. In some embodiments, a neck portion may
configured to
couple a finish with the cylindrical portion.
[0067] The finish generally includes an opening to an interior of the
cylindrical portion. In
some embodiments, the finish may be configured to accommodate a relatively
large headspace
suitable for nitrogen hot-filling the heat-set container with pressurized
contents. The finish may
include at least one thread that is circumferentially disposed on the finish
and configured to
rotatably engage with threads in a container cap so as to retain pressurized
contents within the
heat-set container.
[0068] In some embodiments, the neck portion of the PET preform may be
tapered from a
diameter of the finish to a diameter of the cylindrical portion. A wall
thickness of the neck portion
may be configured to transition to a predetermined wall thickness of the
cylindrical portion that is
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suitable for being blow-molded into the heat-set container. In some
embodiments, the
predetermined wall thickness may be suitable for blow-molding at least the
cylindrical portion into
a heat-set container capable of withstanding nitrogen hot-filling with
pressurized contents.
[0069] In some embodiments for preforms in which the neck finish is foimed
primarily of
PET, the preform may be heated to a temperature of preferably 80 C to 120 C,
with higher
temperatures being preferred for the heat-set embodiments, and given a brief
period of time to
equilibrate. After equilibration, the preform may be stretched to a length
approximating the length
of the final container. Following the stretching, pressurized air, such as
chilled food grade air,
may be forced into the preform which acts to expand the walls of the preform
to fit the mold in
which it rests, thus creating the container. Fluid may be circulated through
the mold so as to
rapidly cool the container contacting the interior surface. The temperature of
the chilled air for
stretching the preform and the temperature of the fluid cooling the mold may
be selected based on
the desired container finish, production time, and the like.
[0070] Figures 7A through 7C illustrate an exemplary embodiment of a
prefoini 90 suitable
for being blow-molded to form a bottle, such as the container 82, in
accordance with the present
disclosure. Similar to the prefoinis 30, 50, the preform 90 comprises a neck
portion 32 and a body
portion 34 that are monolithically fanned. The neck portion 32 begins at an
opening 36 to an
interior of the preform 90 and extends to a tapered portion 92 of the body
portion 34. The tapered
portion 92 comprises a smooth transition from a diameter of the neck portion
32 to a relatively
smaller diameter of a cylindrical 94 portion of the prefolin 90. The
cylindrical portion 94 is a
generally elongate member that extends to an end cap 42.
[0071] As best shown in Fig. 7B, a wall thickness of the cylindrical
portion 94 is substantially
unifolin throughout the cylindrical portion and the end cap 42. A wall
thickness of the tapered
portion 92, however, generally decreases from the wall thickness of the
cylindrical portion 94 to a
relatively thinner wall thickness of the neck portion 32. As discussed herein,
the wall thickness of
the cylindrical portion 94 is relatively greater than the wall thickness of
the neck portion 32 so as
to provide a wall thickness at the desired dimensions of a finished product
after being blow-molded
into the shape and size of a bottle, such as the container 82.
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[0072] As shown in Figs. 7B and 7C, the neck portion 32 may be
characterized by a plurality
of longitudinally oriented internal columns 96 within the opening 36. In the
illustrated
embodiment, the plurality of internal columns 96 comprises three internal
columns that are equally
spaced around the circumference of the neck portion 32. Thus, as shown in Fig.
7C, adjacent
internal columns 96 are positioned at substantially 120-degree intervals
around the circumference
of the neck portion 32. As will be appreciated, incorporating the plurality of
internal columns 96
into the neck portion 32 facilitates incorporating a wall thickness within the
neck portion that is
relatively thinner than conventional neck portions. Thus, the internal columns
96 facilitate a wall
thickness within the neck portion 32 of the preform 90 that reduces the amount
of material needed
to foini the prefoini 90 while still maintaining the necessary degree of
structural integrity to allow
for ease in blow-molding to foini a container that has suitable mechanical
strength to withstand
forces encountered during formation, filling, transportation, and use. It
should be understood,
however, that the number of internal columns 96 may be other than three, and
that the spacing
between adjacent internal columns 96 need not necessarily be uniform, nor
limited to 120-degree
intervals.
[0073] The neck portion 32 is further characterized by a presence of
threads 40 configured to
rotatably engage with similar threads disposed within a cap or other suitable
closure so as to
provide a way to seal contents within the container 82. In the embodiment
illustrated in Fig. 7A,
and as shown in greater detail in Figs. 8A-9D, each of the threads 40
generally extends along a
section of the circumference of the neck portion 32 and approaches a neck ring
98. Thus, when
the threads of a cap are engaged with the threads 40, and the cap is rotated
in a clockwise direction,
the cap advances toward the support ring 38. As best shown in Fig. 8A, the
threads 40 comprise
three threads that each begins at a thread start 102 and extends along a
substantially 144-degree
section of the neck portion 32. The thread start 102 is configured to guide
the thread 40 into a
space, or valley, between adjacent threads of the cap so as to threadably
engage the cap with the
neck portion 32, as described herein. Further, the threads 40 generally are
disposed adjacently to
one another and are spaced unifoirnly around the circumference of the neck
portion 32. In the
embodiment illustrated in Fig. 8A, the thread starts 102 of adjacent threads
40 are spaced at
substantially 120-degree intervals around the perimeter of the neck portion
32. As will be
appreciated, however, more or less than three threads 40 may be incorporated
into the neck portion
32 without deviating beyond the scope of the present disclosure.
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[0074] In some embodiments, one or more exterior columns 104 may be
incorporated into the
neck portion 32. Similar to the internal columns 96, described above, the
exterior columns 104
facilitate a wall thickness within the neck portion 32 of the prefoun 90 that
reduces the amount of
material needed to foun the prefonn while still maintaining a necessary degree
of structural
integrity, as described herein. Thus, the exterior columns 104 may be
incorporated into the neck
portion so as to promote ease in blow-molding to foun a container that has
suitable mechanical
strength to withstand forces encountered during foimation, filling,
transportation, and use
[0075] In the present embodiment, three exterior columns 104, each
comprising a vertically
aligned thicker portion of the neck portion 32, are disposed unifoimly around
the perimeter of the
neck portion, as best shown in Figs. 8B and 8C. In some embodiments, however,
other than three
exterior columns 104 may be disposed around the neck portion 32, such as, by
way of non-limiting
example, two exterior columns disposed on opposite sides of the neck portion
32, or four exterior
columns disposed at 90-degree intervals around the neck portion 32. Further,
the spacing between
adjacent exterior columns 104 need not be unifonn around the perimeter of the
neck portion, but
rather the exterior columns may be disposed at various intervals around the
neck portion.
[0076] Moreover, in some embodiments, the external columns 104 may be
positioned around
the perimeter of the neck portion 32 so as to coincide with the locations of
the internal columns
96. In such embodiments, therefore, the internal columns 96 may be positioned
directly beneath
the external columns 104. Alternatively, in some embodiments, the external
columns 104 may be
positioned at specific intervals between adjacent internal columns 96. For
example, adjacent
internal and external 96, 104 may be separated by 60-degree intervals.
Further, the internal and
external columns 96, 104 need not necessarily be positioned at the same
distance relative to the
opening 36. In the embodiment illustrated in Figs. 7A-9D, for example, the
external columns
104 are positioned above the neck ring 98, whereas the internal columns 96
generally extend from
the neck ring 98 into the tapered portion 92 of the prefoim 90, as best shown
in Fig. 7B. It should
be understood, therefore, that the internal and external columns 96, 104 may
be incorporated onto
the neck portion 32 in any configuration deemed suitable without deviating
beyond the spirit and
scope of the present disclosure.
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[0077] Figure 9A illustrates a cross-sectional view of the neck portion 32,
taken along a line
9A-9A of Fig. 8A. As described above, the neck portion 32 comprises a
generally cylindrical
member having an opening 36 suitable to provide access to an interior of the
container 82. A bevel
106 is disposed at the beginning of the opening 36. The bevel 106 is
configured to enter into
sliding contact with a sealing flange of a suitable cap so as to prevent
contents within the container
82 from leaking out of the container. In some embodiments, the bevel 106 may
compress the
sealing flange to a predetermined degree, thereby forming a tight seal
suitable to retain pressurized
contents within the container 82.
[0078] Figures 9B through 9D illustrate detailed close up views of portions
of the cross-
sectional view of Fig. 9A. A cross-sectional profile of the threads 40 is
illustrated in Fig. 9B. The
threads 40 generally extend outward from the neck portion 32 such that a
valley 108 is disposed
between adjacent threads. The cross-sectional profile of the threads 40 is
configured such that the
threads advantageously engage with similar threads disposed within a suitable
cap for sealing
contents within the container 82. As will be recognized by those skilled in
the art, the valley 108
is configured to allow passage of a thread disposed in the cap to pass between
adjacent threads 40
during tightening of the cap onto the neck portion 32, as described herein.
[0079] Figure 9C illustrates a close up view of the cross-sectional profile
of the neck ring 98.
As shown in Fig. 9C, the neck ring 98 comprises a rounded upper portion 112
and a substantially
flat lower portion 116. As will be appreciated, the rounded upper portion 112
facilitates passing a
tamper-evident ring portion of the cap over the neck ring 98 during assembly
of the cap onto the
container 82. The flat lower portion 116 is configured to retain the tamper-
evident ring positioned
below the neck ring 98 during loosening of the cap. For example, when the cap
is initially installed
onto the container 82 by a manufacturer, the tamper-evident ring easily passes
over the neck ring
98 due to the rounded upper portion 112. When an end-user later loosens the
cap, the flat lower
portion 116 retains the tamper-evident ring below the neck ring 98, causing
the tamper-evident
ring to break loose from the cap. Thus, the flat lower portion 116 of the neck
ring 98 and the
tamper-evident ring of the cap cooperate to indicate to the end-user that the
cap has not been
previously loosened after being installed by the manufacturer.
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[0080] Figure 9D illustrates a close up view of the cross-sectional profile
of the support ring
38. In the embodiment illustrated in Fig. 9D, the support ring 38 comprises a
substantially flat
lower surface 120. As will be recognized, the flat lower surface 120 of the
support ring 38
facilitates supporting the prefottn 90 in the mold 80 during the blow-molding
process described
above and illustrated in Fig. 3.
[0081] The articles described herein may be made from any suitable
thermoplastic material,
such as polyesters including polyethylene terephthalate (PET), polyolefins,
including
polypropylene and polyethylene, polycarbonate, polyamides, including nylons
(e.g. Nylon 6,
Nylon 66, MXD6), polystyrenes, epoxies, acrylics, copolymers, blends, grafted
polymers, and/or
modified polymers (monomers or portion thereof having another group as a side
group, e.g. olefin-
modified polyesters). These materials may be used alone or in conjunction with
each other. More
specific material examples include, but are not limited to, ethylene vinyl
alcohol copolymer
("EVOH"), ethylene vinyl acetate ("EVA"), ethylene acrylic acid ("EAA"),
linear low density
polyethylene ("LLDPE"), polyethylene 2,6- and 1,5-naphthalate (PEN),
polyethylene
terephthalate glycol (PETG), poly( cyclohexylenedimethylene terephthalate ),
polystryrene,
cycloolefin, copolymer, poly-4-methylpentene-1, poly( methyl methacrylate),
acrylonitrile,
polyvinyl chloride, polyvinylidine chloride, styrene acrylonitrile,
acrylonitrile-butadiene-styrene,
polyacetal, polybutylene terephthalate, ionomer, polysulfone, polytetra-
fluoroethylene,
polytetramethylene 1,2-dioxybenzoate and copolymers of ethylene terephthalate
and ethylene
isophthalate. In certain embodiments preferred materials may be virgin, pre-
consumer, post-
consumer, regrind, recycled, and/or combinations thereof.
[0082] In some embodiments polypropylene also refers to clarified
polypropylene. As used
herein, the term "clarified polypropylene" is a broad terni and is used in
accordance with its
ordinary meaning and may include, without limitation, a polypropylene that
includes nucleation
inhibitors and/or clarifying additives. Clarified polypropylene is a generally
transparent material
as compared to the homopolymer or block copolymer of polypropylene. The
inclusion of
nucleation inhibitors helps prevent and/or reduce crystallinity, which
contributes to the haziness
of polypropylene, within the polypropylene. Clarified polypropylene may be
purchased from
various sources such as Dow Chemical Co. Alternatively, nucleation inhibitors
may be added to
polypropylene.
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[0083] As used herein, "PET" includes, but is not limited to, modified PET
as well as PET
blended with other materials. One example of a modified PET is IP A-modified
PET, which refers
to PET in which the IPA content is preferably more than about 2% by weight,
including about 2-
10% IP A by weight, also including about 5-10% IP A by weight. In another
modified PET, an
additional comonomer, cylohexane dimethanol (CHDM) is added in significant
amounts (e.g.
approximately 40% by weight or more) to the PET mixture during manufacture of
the resin.
[0084] Additives may be included in articles herein to provide functional
properties to the
resulting containers. Such additives include those providing enhanced gas
barrier, UV protection,
scuff resistance, impact resistance and/or chemical resistance. Preferred
additives may be prepared
by methods known to those of skill in the art. For example, the additives may
be mixed directly
with a particular material, or they may be dissolved/dispersed separately and
then added to a
particular material. Additives are preferably present in an amount up to about
40% of the material,
also including up to about 30%, 20%, 10%, 5%, 2% and 1% by weight of the
material. In other
embodiments, additives are preferably present in an amount less than or equal
to 1% by weight,
preferred ranges of materials include, but are not limited to, about 0.01% to
about 1%, about 0.01%
to about 0.1%, and about 0.1% to about 1% by weight.
[0085] Another possible additive is microparticulate clay or graphene based
materials. These
materials comprise tiny, micron or sub-micron size (diameter), particles of
materials which
enhance the barrier and/or mechanical properties of a material by creating a
more tortuous path for
migrating gas molecules, e.g. oxygen or carbon dioxide, to take as they
permeate a material and/or
providing added stiffness. In preferred embodiments nanoparticulate material
is present in
amounts ranging from 0.05 to 1% by weight, including 0.1%, 0.5% by weight and
ranges
encompassing these amounts. One preferred microparticulate clay based product
is Cloisite0
available from Southern Clay Products. In certain embodiments preferred
nanoparticles comprise
monmorillonite that may be modified with a ternary or quaternary ammonium
salt. In further
embodiments, such particles comprise organoclays as described in U.S. Patent
No. 5,780,376,
the entire disclosure of which is hereby incorporated by reference and fauns
part of the disclosure
of this application. Other suitable organic and inorganic microparticulate
clay based or nano-sized
products may also be used. Both man-made and natural products are also
suitable.
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[0086] In some embodiments, the UV protection properties of the material
may be enhanced
by the addition of one or more additives. In a preferred embodiment, the UV
protection material
used provides UV protection up to about 350 rim or less, preferably about 3 70
nm or less, more
preferably about 400 nm or less. The UV protection material may be used as an
additive with
layers providing additional functionality or applied separately as a single
layer. Preferably
additives providing enhanced UV protection are present in the material from
about 0.05 to 20% by
weight, but also including about 0.1%, 0.5%, 1%, 2%, 3%, 5%, 10%, and 15% by
weight, and
ranges encompassing these amounts. Preferably the UV protection material is
added in a form that
is compatible with the other materials. In some embodiments, a preferred UV
protection material
comprises a polymer grafted or modified with a UV absorber that is added as a
concentrate. Other
preferred UV protection materials include, but are not limited to,
benzotriazoles, phenothiazines,
and azaphenothiazines. UV protection materials may be added during the melt
phase process prior
to use, e.g. prior to injection molding or extrusion. Suitable UV protection
materials are available
from Milliken, Ciba and Clariant.
[0087] While the invention has been described in terms of particular
variations and illustrative
figures, those of ordinary skill in the art will recognize that the invention
is not limited to the
variations or figures described. In addition, where methods and steps
described above indicate
certain events occurring in certain order, those of ordinary skill in the art
will recognize that the
ordering of certain steps may be modified and that such modifications are in
accordance with the
variations of the invention. Additionally, certain of the steps may be
performed concurrently in a
parallel process when possible, as well as performed sequentially as described
above. To the extent
there are variations of the invention, which are within the spirit of the
disclosure or equivalent to
the inventions found in the claims, it is the intent that this patent will
cover those variations as
well. Therefore, the present disclosure is to be understood as not limited by
the specific
embodiments described herein, but only by scope of the appended claims.
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