Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MULTIPLE PLY WEB SUPPLY ROLL FOR FORM, FILL, SEAL PACKAGING
MACHINERY
CROSS-REFERENCE TO RELATED APPLICATION:
This application claims priority to U.S. Patent Application Serial No.
11/713,471 filed
on March 2, 2007, which is incorporated herein in its entirety and made a part
hereof.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT:
Not Applicable.
BACKGROUND OF THE INVENTION:
Technical Field
The present invention provides a roll of container sidewall material having a
first ply
and a second ply wound together about a common axis to fonn a stack of layers
along a
radius of the roll alternating between the frst ply and the second ply. The
roll can have a
leading edge of the first ply and the second ply fed into a vertical form,
fill and seal
machinery where the machinery forms a filled container having: (1) the first
ply and the
second ply forming a first wall of the container and an opposed second wall is
formed from a
different supply of material, or (2) the first ply and the second ply form
both opposed walls of
the container or (3) the first ply forms a first wall of the container and the
second ply forms
an opposed second wall of the container.
Background Art
Collapsible plastic bags are often used to store liquid products such as
chemicals, soft
drink syrup, wine, fruit juices, medical fluids and food condiments. For
certain applications
the plastic bags are typically housed in a corrugated paperboard box to aid in
the transporting,
handling and dispensing of the product. Such packaging systems are commonly
referred to
as "bag-in-box" packaging systems.
The plastic bags typically have sidewalls sealed along a peripheral seam to
define a
fluid containing chamber. A spout or a fitment provides access to the fluid
chamber for
filling and dispensing the product within the bag. Liquid filled containers
are often provided
using form, fill and seal equipment. The present invention provides a roll of
a multiple- ply
material for forming containers, a method for forming a spool of multiple-ply
material for use
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in packaging machinery, and a method for forming containers from such multiple-
ply
material.
These and other aspects and attributes of the present invention will be
discussed with
reference to the following drawings and accompanying specification.
BRIEF DESCRIPTION OF THE DRAWINGS:
FIG. I is a perspective view of a roll of container wall material having
consecutive
layers of a first ply and a second ply;
FIG. 2 is an end view of the roll of FIG. 1;
FIG. 3 is a schematic view of one method for forming the roll of FIG. 1 from a
first
preformed roll of the first ply and a second preformed roll of the second ply;
FIG. 4 is a schematic view of another method for forming the roll of FIG. I by
combining together extrudates or laminates of the first ply and the second
ply;
FIG. 5 is a schematic view of another method fer forming the roll of FIG. 1 by
combining an extrudate or laminate of the first ply and a second ply on a
preformed roll;
FIG. 6 is a schematic view of a vertical form, fill and seal machinery;
FIG. 7 is a side elevation view in vertical cross section of a fitment;
FIG 8 is a perspective view of a fluid container having a fitment on a planar
surface of
a wall of the container;
FIG. 9 is a perspective view of a fluid container having a fitment extending
through a
seam or end wall of the container;
FIG. 10 is a cross-sectional view of a multiple layer film structure; and
FIG. I 1 is a cross-sectional view of a monolayer film structure.
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DETAILED DESCRIPTION OF THE INVENTION:
While this invention is susceptible of embodiment in many different forms,
there is
shown in the drawings, and will be described herein in detail, specific
embodiments thereof
with the understanding that the present disclosure is to be considered as an
exemplification of
the principles of the invention and is not intended to limit the invention to
the specific
embodiments illustrated.
FIG. 1 shows a roll or spool 10 of material for fabricating a container using
packaging
machinery such as vertical form, fill and seal machinery. The roll 10 has a
longitudinal axis
12 about which the material 14 is wound. As shown in FIGS. 1 and 2, the roll
when viewed
along a radius, the first ply and the second ply form consecutive stacked
layers. The roll is
formed by placing a first ply of material 20 into surface contact with a
second ply 22 of
material and then winding both plies about the axis 12. FIG. 2 shows that the
first ply 20 and
the second ply 22 are coextensive and form stacked layers from the center of
the roll 26 to a
leading edge 28 of the roll. However, it is contemplated that either the first
ply or the second
ply could be used exclusively as a starter section at the center of the roll
or as an outer section
at the leading edge of the roll without departing from the invention. The
outer section could
be used to protect the roll from cosmetic or physical damage such as scratches
or punctures
and the like. Also, while the roll 10 shows two plies of material it is
contemplated additional
plies could be used such as three to ten plies without departing from the
scope of the present
invention. The material for fabricating the plies will be discussed in greater
detail below, but,
in short, can be selected from polymeric material, paper, and metal foil.
FIG. 3 shows one method of forming the roll 10 by drawing the first web of
material
from a roll 30 of preformed material and the second web of material from a
second roll 32 of
preformed material, positioning the first ply and the second ply to place
their respective
opposed lateral edges into registration with one another and then bringing a
planar surface 34
of the first ply into surface contact with the second ply and winding the
stacked plies about
the axis 12 to form roll 10. Thus, in one preferred form of the invention the
first ply is not
connected to the second ply. In another preferred form of the invention, the
first ply will be
connected to the second ply along one or both pairs of each of the plies
opposed lateral edges.
When both of each plies lateral edges are attached or connected to one another
the first ply
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and the second ply form a tube of material that is wound about the axis 12 to
form the roll 10.
The first ply can be connected to the second ply through any suitable
technique well known
in the art such as by inductive or conductive heat sealing, or welding, or by
using an
adhesive. The seal between the first ply and the second ply can be a permanent
seal or a peel
seal. A permanent seal is one that cannot be separated without damaging the
first ply or the
second ply. A peel seal is one that is meant to be separated by hand or
machine without
damaging the first ply or the second ply. Each of the plies of the tube of
material will have a
central planar surfaces extending between the lateral edges and one ply's
planar surface will
remain unattached to the other ply's planar surface. It is also contemplated
that the first ply
can be connected to the second ply in locations other than the lateral edges
and can form a
continuous line over a portion of the length of the plies or can be
intermittent lines or spots.
FIG. 4 shows an alternative method for forming the spool 10. In this
embodiment, the
first ply and the second ply 20, 22 are provided from equipment used to form
the material 40
such as an extrusion die, coextrusion die, lamination equipment, extrusion
lamination, blown
extrusion and the like and the first ply and the second ply are cooled,
quenched, set or
otherwise placed in a form suitable to be placed in surface contact with one
another and
wound into the roll 10.
FIG. 5 shows yet another alternative embodiment for forming the spool 10 which
is a
combination of the embodiments shown in FIGS. 3 and 4. In the embodiment shown
in FIG.
5, the first ply of material 20 is drawn from the preformed roll of material
30 and the second
ply of material is drawn from the material forming equipment 40.
FIG. 6 shows the use of the multiple-ply roll 10 of material for use in
package
forming machinery, and more particularly, in vertical form, fill, and seal
(VFFS) machinery
50 for making containers 51 with a liquid content in the range of about 5 to
20 liters. The
VFFS machinery 50 has a support 52 for one supply roll of film material 10 and
optionally a
second support 53 for a second supply roll of film material 10'. Guide rollers
or other support
structures are provided to support and guide a web of film drawn from the one
or both of the
supply rolls to direct the film material along a feed path. A fitment
attaching station 54 is
optionally provided in the feed path for attaching a fluid access member 60 to
a planar
surface of one of the webs of film material 14 drawn from the supply roll 10.
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FIG. 7 shows the fluid access member or fitment 60 has a generally cylindrical
wall
62 defming a fluid pathway 63 therein. The wall 62 extends axially from a
circular flange 64.
A cap 66 can be attached to the tube 62 with a set of mating threads 68
located on interfacing
portions of the cap and wall. In one prefeired form of the invention, a
generally circular hole
is cut through the web of material 14 and the tube 62 is inserted through the
hole and the
flange 64 is attached to a planar surface of the web of material 14 by heat
sealing or other
suitable attaching technique. The fitment 60 allows for access to a fluid
chamber of a
completed container from outside the container.
A film feed drive (not shown) is provided in the VFFS machinery 50 for
displacing
the film sheet or sheets along the feed path and through a pouch former 70. In
embodiments
utilizing two supply rolls of film 10 and 10' as shown, the two sheets of film
are brought into
the pouch forming section 70 where the two sheets of material are positioned
to place the
opposed lateral edges of each sheet of film material into registration with
one another and are
welded together by heat welding apparatus 72 to form a tube disposed about a
drop tube 74
having a liquid fill tube therein. A horizontally extending sealing apparatus
76 forms a
bottom seal for a pouch to be filled and a top seal for a filled pouch. A
severing apparatus 78
detaches the filled pouch from the pouch to be filled and the severed pouch
drops from the
container into an area adjacent the VFFS machinery 50 where the filled pouch
will be
prepared for shipping. FIG. 6 shows the filled containers 51 on an optional
conveyor belt 80
where the filled containers are moved to an area away from the machinery 51
where they will
be prepared for use or shipping. A support member (not shown) is provided to
support a
pouch while it is being filled to prevent the weight of the liquid in the
pouch from tensioning
the film at a time when the film experiences a loss of surface tension due to
heating of the
film by the horizontal sealing apparatus 76. The support apparatus also
constrains the pouch
being filled to prevent it from ballooning out during the filling cycle. The
support apparatus
has a discharge gate section to discharge the filled pouch after the
horizontal sealing cycle.
In embodiments using two separate rolls of film, as shown in FIG. 6, at least
one of
the rolls 10 or 10' will be the multiple-ply roll 10 described herein. The
second supply roll of
film 10' can be a multiple-ply roll having or a single ply roll. If the second
supply roll of
film 10' is a multiple-ply roll it can have the same number or a different
number of plies as
the first supply roll, it can have the same types of materials or different
materials as the first
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roll, it can have the same order of layers of material in the stack or a
different order of
materials in the stack and any combination of these variables.
In embodiments of VFFS machinery using a single roll of multiple ply film the
machinery can make both sidewalls of the multiple ply film or it can separate
the stack of
plies into a first ply or stack of plies and a second ply or stack of plies to
make a first sidewall
from the first ply or a stack of plies and a second sidewall from the second
ply or stack of
plies. In both embodiment the film material will either be folded or otherwise
positioned to
form a tubular web of material about the filling tube 74 and filled and sealed
as described
above in reference to FIG. 6.
The fluid filled into the container flows from a container 81 which is in
liquid flow
communication with the filling tube 74. Liquids that are commonly filled in
this fashion
using a VFFS machinery include wine, soft drink syrup concentrate, juices,
medical solutions
among numerous others.
FIGS. 8 and 9 show the filled container 51 having opposed walls 82 and 84
defining
the fluid chamber 86. The container 51 is shown having two opposed walls to
form a pillow
type container but it is contemplated that additional walls could be used to
form gussets or to
form a stand up container or the like as is well known to those skilled in the
art. The
container 51 is shown with the optional fitment 60 that provides fluid access
to the fluid
chamber 86 from outside the container 51. The fitment can be attached to the
planar surface
as described above in reference to FIG. 6, or it can be attached in a separate
operation. It is
also contemplated that the fitment could be modified to have a flange portion
extending
between the sidewalls of the container and being attached to both sidewalls
and having a
portion extending outside of the container as shown in FIG. 9.
Suitable fitments 60 are well known to those skilled in the art and include
fitments
having portions for dispensing wine or docking to a line of a soda fountain,
or that can be
poured from, can be accessed through a straw or that can be directly drank
from or that has a
recloseable tap or the like. These parts can be formed from polymeric
materials using
injection molding techniques or the like.
FIGS. 10 and 11 show respectively a multiple layer film structure 100 and a
monolayer film structure 102 that can be used to form a ply of the multiple-
ply rolls or
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single-ply rolls of material 10, 10' discussed above. The multiple layer
structure 100 can
have from 2 to 10 layers, for example, and is shown in FIG. 10 having three
layers. It should
be understood that the individual layers of the multiple layer structure are
attached or
connected from one lateral edge to the other unlike the multiple ply
structures material 14.
While tie layers are not shown, it is contemplated that tie layers may be
positioned between
layers to prevent delamination of the multiple layer structure or to provide
other physical
properties needed from the structure. The multiple layer structure and the
monolayer
structure can be formed using polymer forming techniques well known to those
skilled in the
art including extrusion, coextrusion, extrusion lamination, lamination, blown
extrusion and
the like. Suitable material for forming a layer of the film includes polymeric
material, paper
and metal foil.
Suitable polymeric material includes polyolefins, ethylene and lower alkyl
acrylate
copolymers, ethylene and lower alkyl substituted alkyl acrylate copolymers,
ethylene vinyl
acetate copolymers, polyimides, polysulfones, polycarbonates, polyethers,
polyetheramides,
polyetherimides, polystyrenes, ethylene vinyl alcohols, ethylene vinyl
acetates, polyvinyl
chlorides, polyvinyledine chlorides, polybutadienes, polyesters, polyamides,
polystyrenes and
styrene and hydrocarbon copolymers.
Suitable polyolefins include homopolymers and copolymers obtained by
polymerizing
alpha-olefins containing from 2 to 20 carbon atoms, and more preferably from 2
to 10
carbons. Therefore, suitable polyolefins include polymers and copolymers of
propylene,
ethylene, butene-1, pentene-1, 4-methyl-l-pentene, hexene-1, heptene-1, octene-
1, nonene-1
and decene-1. Most preferably the polyolefin is a homopolymer or copolymer of
propylene
or a homopolymer or copolymer of polyethylene.
Suitable homopolymers of polypropylene can have a stereochemistry of
amorphous,
isotactic, syndiotactic, atactic, hemiisotactic or stereoblock. In one
preferred form of the
invention the homopolymer of polypropylene is obtained using a single site
catalyst.
Suitable copolymers of propylene are obtained by polymerizing a propylene
monomer
with an a-olefin having from 2 to 20 carbons. In a more preferred form of the
invention, the
propylene is copolymerized with ethylene in an amount by weight from about 1%
to about
20%, more preferably from about 1% to about 10% and most preferably from 2% to
about
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5% by weight of the copolymer. The propylene and ethylene copolymers may be
random or
block copolymers. In a preferred form of the invention, the propylene
copolymer is obtained
using a single-site catalyst.
It is also possible to use a blend of polypropylene and a-olefm copolymers
wherein
the propylene copolymers can vary by the number of carbons in the a -olefin.
For example,
the present invention contemplates blends of propylene and a-olefm copolymers
wherein one
copolymer has a 2 carbon a-olefin and another copolymer has a 4 carbon a-
olefin. It is also
possible to use any combination of a-olefins from 2 to 20 carbons and more
preferably from
2 to 8 carbons. Accordingly, the present invention contemplates blends of
propylene and a-
olefin copolymers wherein a first and second a-olefins have the following
combination of
carbon numbers: 2 and 6, 2 and 8, 4 and 6, 4 and 8. It is also contemplated
using more than 2
polypropylene and a-olefin copolymers in the blend. Suitable polymers can be
obtained
using a catalloy procedure.
It may also be desirable to use a high melt strength polypropylene. High melt
strength
polypropylenes can be a homopolymer or copolymer of polypropylene having a
melt flow
index within the range of 10 grams/10 min. to 800 grams/10 min., more
preferably 30
grams/10 min. to 200 grams/10 min, or any range or combination of ranges
therein. High
melt strength polypropylenes are known to have free-end long chain branches of
propylene
units. Methods of preparing polypropylenes which exhibit a high melt strength
characteristic
have been described in U.S. Patent Nos. 4,916,198; 5,047,485; and 5,605,936
which are
incorporated herein by reference and made a part hereof. One such method
includes
irradiating a linear propylene polymer in an environment in which the active
oxygen
concentration is about 15% by volume with high energy ionization energy
radiation at a dose
of 1 to 10 megarads per minute for a period of time sufficient for a
substantial amount of
chain scission of the linear propylene polymer to occur but insufficient to
cause the material
to become gelatinous. The irradiation results in chain scission. The
subsequent
recombination of chain fragments results in the formation of new chains, as
well as joining
chain fragments to chains to form branches. This further results in the
desired free-end long
chain branched, high molecular weight, non-linear, propylene polymer material.
Radiation is
maintained until a significant amount of long chain branches form. The
material is then
treated to deactivate substantially all the free radicals present in the
irradiated material.
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High melt strength polypropylenes can also be obtained as described in U.S.
Patent
No. 5,416,169, which is incorporated in its entirety herein by reference and
made a part
hereof, when a specified organic peroxide (di-2-ethylhexyl peroxydicarbonate)
is reacted
with a polypropylene under specified conditions, followed by melt-kneading.
Such
polypropylenes are linear, crystalline polypropylenes having a branching
coefficient of
substantially 1, and, therefore, has no free end long-chain branching and will
have a intrinsic
viscosity of from about 2.5 dl/g to 10 dl/g.
Suitable homopolymers of ethylene include those having a density of greater
than
0.915 g/cc and includes low density polyethylene (LDPE), medium density
polyethylene
(MDPE) and high density polyethylene (HDPE).
Suitable copolymers of ethylene are obtained by polymerizing ethylene monomers
with an a-olefin having from 3 to 20 carbons, more preferably 3-10 carbons and
most
preferably from 4 to 8 carbons. It is also desirable for the copolymers of
ethylene to have a
density as measured by ASTM D-792 of less than about 0.915 g/cc and more
preferably less
than about 0.910 g/cc and even more preferably less than about 0.900 g/cc.
Such polymers
are oftentimes referred to as VLDPE (very low density polyethylene) or ULDPE
(ultra low
density polyethylene). Preferably the ethylene a-olefin copolymers are
produced using a
single site catalyst and even more preferably a metallocene catalyst system.
Single site
catalysts are believed to have a single, sterically and electronically
equivalent catalyst
position as opposed to the Ziegler-Natta type catalysts which are known to
have a mixture of
catalysts sites. Such single-site catalyzed ethylene a-olefins are sold by Dow
under the trade
name AFFINITY, DuPont Dow under the trademark ENGAGE and by Exxon under the
trade name EXACT. These copolymers shall sometimes be referred to herein as m-
ULDPE.
Suitable copolymers of ethylene also include ethylene and lower alkyl acrylate
copolymers, ethylene and lower alkyl substituted alkyl acrylate copolymers and
ethylene
vinyl acetate copolymers having a vinyl acetate content of from about 8% to
about 40% by
weight of the copolymer. The term "lower alkyl acrylates" refers to comonomers
having the
formula set forth in Diagram 1:
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tt
..~= .
f J -~u~s
uR.
Diagram 1
The R group refers to alkyls having from I to 17 carbons. Thus, the term
"lower alkyl
acrylates" includes but is not limited to methyl acrylate, ethyl acrylate,
butyl acrylate and the
like.
The term "alkyl substituted alkyl acrylates" refers to comonomers having the
formula
set forth in Diagram 2:
Rt
H2C.
Diagram 2.
Ri and R2 are alkyls having 1-17 carbons and can have the same number of
carbons or
have a different number of carbons. Thus, the term "alkyl substituted alkyl
acrylates"
includes but is not limited to methyl methacrylate, ethyl methacrylate, methyl
ethacrylate,
ethyl ethacrylate, butyl methacrylate, butyl ethacrylate and the like.
Suitable polybutadienes include the 1,2- and 1,4-addition products of 1,3-
butadiene
(these shall collectively be referred to as polybutadienes). In a more
preferred form of the
invention, the polymer is a 1,2-addition product of 1,3 butadiene (these shall
be referred to as
"1,2 polybutadienes"). In an even more preferred form of the invention, the
polymer of
interest is a syndiotactic 1,2-polybutadiene and even more preferably a low
crystallinity,
syndiotactic 1,2 polybutadiene. In a preferred form of the invention, the low
crystallinity,
syndiotactic 1,2 polybutadiene will have a crystallinity less than 50%, more
preferably less
than about 45%, even more preferably less than about 40%, even more preferably
the
crystallinity will be from about 13% to about 40%, and most preferably from
about 15% to
about 30%. In a preferred form of the invention, the low crystallinity,
syndiotactic 1,2
polybutadiene will have a melting point temperature measured in accordance
with ASTM D
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3418 from about 70 C to about 120 C. Suitable resins include those sold by JSR
(Japan
Synthetic Rubber) under the grade designations: JSR RB 810, JSR RB 820, and
JSR RB 830.
Suitable polyesters include polycondensation products of di-or polycarboxylic
acids
and di or poly hydroxy alcohols or alkylene oxides. In one preferred form of
the invention
the polyester is a polyethylene terephthalate (PET) or PET ethylene glycol
modified. In
another form of the invention, the polyester is a polyester ether. Suitable
polyester ethers are
obtained from reacting 1,4 cyclohexane dimethanol, 1,4 cyclohexane
dicarboxylic acid and
polytetramethylene glycol ether and shall be referred to generally as PCCE.
Suitable PCCE's
are sold by Eastman under the trade name ECDEL. Suitable polyesters further
include
polyester elastomers which are block copolymers of a hard crystalline segment
of
polybutylene terephthalate and a second segment of a soft (amorphous)
polyether glycols.
Such polyester elastomers are sold by Du Pont Chemical Company under the trade
name
HYTREL .
Suitable polyamides include those that result from a ring-opening reaction of
lactams
having from 4-12 carbons. This group of polyamides therefore includes nylon 6,
nylon 10
and nylon 12. Acceptable polyamides also include aliphatic polyamides
resulting from the
condensation reaction of di-amines having a carbon number within a range of 2-
13, aliphatic
polyamides resulting from a condensation reaction of di-acids having a carbon
number within
a range of 2-13, polyamides resulting from the condensation reaction of dimer
fatty acids, and
amide containing copolymers. Thus, suitable aliphatic polyamides include, for
example,
nylon 6,6 nylon 6,10 and dimer fatty acid polyamides.
The styrene of the polystyrene and the styrene and hydrocarbon copolymer
includes
styrene and the various substituted styrenes including alkyl substituted
styrene and halogen
substituted styrene. The alkyl group can contain from I to about 6 carbon
atoms. Specific
examples of substituted styrenes include alpha-methylstyrene, beta-
methylstyrene,
vinyltoluene, 3-methylstyrene, 4-methylstyrene, 4-isopropylstyrene, 2,4-
dimethylstyrene, o-
chlorostyrene, p-chlorostyrene, o-bromostyrene, 2-chloro-4-methylstyrene, etc.
Styrene is
the most preferred.
The hydrocarbon portion of the styrene and hydrocarbon copolymer includes
conjugated dienes. Conjugated dienes which may be utilized are those
containing from 4 to
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about 10 carbon atoms and more generally, from 4 to 6 carbon atoms. Examples
include 1,3-
butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl- 1,3-butadiene,
chloroprene, 1',3-
pentadiene, 1,3-hexadiene, etc. Mixtures of these conjugated dienes also may
be used such as
mixtures of butadiene and isoprene. The preferred conjugated dienes are
isoprene and 1,3-
butadiene.
The styrene and hydrocarbon copolymers can be block copolymers including di-
block, tri-block, multi-block, star block, and mixtures thereof. Specific
examples of diblock
copolymers include styrene-butadiene, styrene-isoprene, and the hydrogenated
derivatives
thereof. Examples of triblock polymers include styrene-butadiene-styrene,
styrene-isoprene-
styrene, alpha-methylstyrene-butadiene-alpha-methylstyrene, and alpha-
methylstyrene-
isoprene-alpha-methylstyrene and hydrogenated derivatives thereof.
The selective hydrogenation of the above block copolymers may be carried out
by a
variety of well known processes including hydrogenation in the presence of
such catalysts as
Raney nickel, noble metals such as platinum, palladium, etc., and soluble
transition metal
catalysts. Suitable hydrogenation processes which can be used are those
wherein the diene-
containing polymer or copolymer is dissolved in an inert hydrocarbon diluent
such as
cyclohexane and hydrogenated by reaction with hydrogen in the presence of a
soluble
hydrogenation catalyst. Such procedures are described in U.S. Patent Nos.
3,113,986 and
4,226,952, the disclosures of which are incorporated herein by reference and
made a part
hereo f.
Particularly useful hydrogenated block copolymers are the hydrogenated block
copolymers of styrene-isoprene-styrene, such as a styrene-(ethylene/propylene)-
styrene block
polymer. When a polystyrene-polybutadiene-polystyrene block copolymer is
hydrogenated,
the resulting product resembles a regular copolymer block of ethylene and 1-
butene (EB). As
noted above, when the conjugated diene employed is isoprene, the resulting
hydrogenated
product resembles a regular copolymer block of ethylene and propylene (EP).
One example
of a commercially available selectively hydrogenated is KRATON G-1652 which is
a
hydrogenated SBS triblock comprising 30% styrene end blocks and a midblock
equivalent is
a copolymer of ethylene and 1-butene (EB). This hydrogenated block copolymer
is often
referred to as SEBS. Kraton G-1657 is a blend of SEBS triblock and SBS diblock
which is
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also suitable. Other suitable SEBS or SIS copolymers are sold by Kurary under
the
tradename SEPTON and HYBRAR .
It may also be desirable to use graft modified styrene and hydrocarbon block
copolymers by grafting an alpha,beta-unsaturated monocarboxylic or
dicarboxylic acid
reagent onto the selectively hydrogenated block copolymers described above.
The block copolymers of the conjugated diene and the vinyl aromatic compound
are
grafted with an alpha,beta-unsaturated monocarboxylic or dicarboxylic acid
reagent. The
carboxylic acid reagents include carboxylic acids per se and their functional
derivatives such
as anhydrides, imides, metal salts, esters, etc., which are capable of being
grafted onto the
selectively hydrogenated block copolymer. The grafted polymer will usually
contain from
about 0.1 to about 20%, and preferably from about 0.1 to about 10% by weight
based on the
total weight of the block copolymer and the carboxylic acid reagent of the
grafted carboxylic
acid. Specific examples of useful monobasic carboxylic acids include acrylic
acid,
methacrylic acid, cinnamic acid, crotonic acid, acrylic anhydride, sodium
acrylate, calcium
acrylate and magnesium acrylate, etc. Examples of dicarboxylic acids and
useful derivatives
thereof include maleic acid, maleic anhydride, fumaric acid, mesaconic acid,
itaconic acid,
citraconic acid, itaconic anhydride, citraconic anhydride, monomethyl maleate,
monosodium
maleate, etc.
The styrene and hydrocarbon block copolymer can be modified with an oil such
as the
oil modified SEBS sold by the Shell Chemical Company under the product
designation
KRATON G2705.
It is also contemplated the layers can be formed from polymer blends of the
components described above.
In a preferred form of the invention, the multiple layer structure 100 will
have a first
solution contact layer 104 of a polyethylene, a second intermediate layer 106
of a polyamide
or an ethylene vinyl alcohol copolymer and an outer layer 108 of a polyamide
or an ethylene
vinyl alcohol copolymer. It is contemplated using tie layers (not shown) or
adhesives
between these layers. In a preferred form of the invention, the monolayer
structure will be a
polyethylene.
CA 02678365 2009-08-14
WO 2008/109054 PCT/US2008/002827
-14-
Also, in a most preferred form of the invention one of the first ply or the
second ply
will be fabricated from the multiple layer structure 100 and the other ply
will be formed from
the monolayer structure. In a most preferred form of the invention, one
container wall will be
formed from a two ply structure 20, 22 having the first ply 20 of a multiple
layer structure.
Even more preferably the multiple layer structure of ply 20 will have layers
stacked in an
order, from solution contact layer to outer layer, of
polyethylene/tie/ethylene vinyl alcohol or
polyamide/tie/ethylene vinyl alcohol or polyamide. The second ply 22 will be
of a
monolayer structure 102 and even more preferably of polyethylene. The opposed
wall of the
container will be formed from a monolayer structure and even more preferably a
polyethylene.
From the foregoing, it will be observed that numerous variations and
modifications
may be effected without departing from the spirit and scope of the invention.
It is to be
understood that no limitation with respect to the specific apparatus
illustrated herein is
intended or should be inferred. It is, of course, intended to cover by the
appended claims all
such modifications as fall within the scope of the claims
