Note: Descriptions are shown in the official language in which they were submitted.
WO93/06159 PCT/US92/080~
2 1 1 o ~ ~ ~
BARRIER FILM
BACKGROU~D
l.Field of the Invention
The present invention relates to thermopla~tic
S films and film forming compositions; ~ore particularly
the present invention re~ates to film forming
compositions comprising polychlorotrifluoroethylene and
f~lms formed therefrom where such filmc feature
improved water vapor transmission barrier properties.
2.Description of the Prior Art
As will certainly be appreciated by tho~e
conversant with the art a wide of thermoplastic resins
~;~ are presently known. Article~ formed from such
thermoplastic resins, i.e., shaped profil~s, plates,
sheets, films, complex article~, all which feature
physical and chemical property ch~acteristics which
~ are directly related to thermoplastic resin from which
;~ they are formed. Films formed from thermoplastic
resins feature chemical and physical char~cteristics
which are directly related to the thermoplastic resin
which they are formed.
Important physical characteristics of films which
are of great interest to the art include the
permeability of the film and its consequent resis~ance
to the transmission of gases, aromas, and~or vapors
such as water vapor. Such properties are especially
important in tha film art as films Are often utilized
in applications wherein such properties are critical;
one example of which include~ the use of films as a
packaging material for foodstuf~s or medicamants. A
further application is the utilization of such films
~ ~ .
WO93/06159 PCT/US92/08~
211~925
- 2 -
and/or composite films comprising two or more layers of
two or more films forming for use in bags, as a
wrapping material, or alternately for formed containers
In applications such as those latter described, it is
highly desirable to utilize two or more films to form a
multilayered film structure which provides structural
integrity, low vapor or gas transmission, and good
formability.
While there-are films presently known to the art
provide useful structures, there remain6 a continuing
need in the art for further improvemants in films and
film structures, particularly those which provide a
film structure featuring low water vapor transmission,
and good physical characteristics.
SU~ARY
According to one aspect of thQ present invention,
there is provided an improved film structure comprising
a poly(chlorotrifluoroethyl~ne) (hereinafter sometimes
interchangeably referred to as ~PCTFE~) film which
features low water vapor transmission and good physical
strength.
In a still further aspect of the pre~ent
invention, there is provided an improved PCTFE film
which pro~ides improved resi~tance to ~hQ transmission
of water vapor at film thicknesses ~reviously
unavailable to art prior to the presant invention.
In a still further aspect of the present
invention, there is provided an improved PCTFE film
having a thickness up to about 15 mils which features
improved water vapor transmission rate properties.
In a further aspect of tha pre~ent invention,
there is provided a film structure comprising at least
one layer of a high barrier PCTFE film which may be
used in the construction of a multi-layer film
W093/06159 PCT/US92/08~
2 S
structure which optionally may be permanently deformed
to form an article.
In a yet further aspect of the present invention,
there is provided a film structure comprising at least
one layer of a high barrier PCTFE film which may be
laminated with at least one further film of a
dissimilar composition, wherein the structure is a
multilayered thermoformed article which is especially
useful as a packaging container for medicaments or
pharmaceutical compositions.
These and yet further aspects of the present
invention will become more apparent with reference to
the following description of the present invention.
,
DESCRIPTION OF INVENrION AND THE PREF~RRED EMBODIMENTS
The present invention provide~ a
poly(chlorotrifluoroethylene) PCTFE film with improved
w~ter vapor barrier properties over other PCFTE films
known to the art. The PCTFE film t~ught herein may be
a single film structure or in the alternàtive, the
PCTFE film aa taught in the present invention may be
utilized in forming a multi-l~yer film structure
wherein the PCTFE film comprises at least a single
layer of a multi layer film. Such films as taught
hRrein may ~e utilized in the formation o~ articles
whic~ include the filmæ according to the present
invention. Contemplated among these ~rticles include
bags, sheeting used for wrapping ~rticles, or thermo-
formed containers such as receptacles for foodstuffs,
medicaments, pharmaceutical compositions, as well as
o~her compositions and materials.
In accordance with the present invention, there
are pFovided multi-layer film constructions which
comprise at least one film layer formed from a PCTFE
:
~ 35 film forming resin wherein said film forming resin
WO93/06lS9 PCT/US92/08
2 11 ~9~ 4 -
exhibits prior to its formation as a film a number
average molecular weight "M~" of less than about
1,000,000, preferably and less than or equal to about
800,000 and which PCTFE film forme~ therefrom exhibits
improved b~rrier properties. A PCTFE film forming
resins having a number ~verage molecular weight of
about 750,000 or less is most particularly preferred.
The number aver~ge molecular weight of the PCTFE film
forming resin may be determined in accordance with
conventional techniques, for example by determining the
intrinsic viscosity, "~' of a sample of t~e PCTFE resin
;~ in a solvent such as 2,5-dichlorobenzotrifluoride
wherein the intrinsic viscosity of the sample may be
correlated to the Mn by the relationship:
t~] - 6.15 x 10-s(Nn)0 74.
Such a method is more fully described in Encyclopedia
of Polymer Science ~nd Engineering, (c) 1985, Volume 3,
-~ - published by John Wiley & Sons, at p~ge 476.
The film forming resins used to form the multi-
layer film constructions provided by the present
invention may also be alternately be characterized in
accordance with the specifications outlined in ASTM-D
1430-81 which proYides the "zero strength time" or
interchangeably referred to as the n ZST" of the film.
Briefly, ASTM-D 1430-81 utilizes a co~pre ~ion molded
test sample form~d of the PCTFE resin having dimensions
of about 1.6~m by 4.8 mm by 50 mm, and which h~s dual
"v" shaped notches in the center; the sample is
suspended from one end with a 7.5 g weight suspended to
the other, lower end in an oven at 250C. The ZST
value is the time in seconds after which the sample
breaks. The ZST value is known to reasonably correlate
to the molecular weight of the resin used to form the
test sample. In the practice of the pre~ent invention,
the PCTFE film forming resin exhibits prior to its
: ~
W093/06t~9 PCT/US92/08~
2~18~2~
formation as a film said PCTFE film forming exhibits a
zero strength time of less ~han about 200, preferably
less than or equal to or about 180, and most preferably
less than or equal to about 150.
S The PCTFE film forming film to be ultimately used
in the multi-layer films are formed from a PCTFE film
forming having the qualities described immediately
above. Conventional methods may be utilized or
modified to produce a suitable film forming resin. Such
processes include bulk polymerization via the
utilization of one or more peroxides as an intiating
system; aqueous suspension polymerization with redox-
initiator systems which include one or more alkali
m~tal persulfates as an oxidant, one or more alk~li
metal bisulfites as activators, ~nd ~etal salts as
accelerators; emulsion polymerization utilizing
fluorocarbon and chlorofluorocarbon emulsifiers are
also known. The molecular weight of the PCTFE film
forming resin produced ~ay be controlled by variance of
the reactor temperature and presaure, as well as the
reaction time in order to produce suitable PCTFE film
forming resinO
By way of example, one suitable process, a
reduction-oxida~ion type reaction, ~ompri es the steps
of charging a sufficient quantity of the starting
reactant PCTFE to a glass lined, jack~ted, stirred
sealable ~eactor which is capable of oper~ting at least
to pressures of about 200 psig~ I~ is preferred that
the reactor include a cooling ~acket or other cooling
means which is capable to withdraw heat from the
reactor during the production process and there~y
provide a means of temperature contxol during the
- reaction of the contents of the reactor.
The reaction system requires the use of an
initiator/catalyst system to produce the PCTFE film
WO93~0615g PCT/US92/0~K~
2 ~ ~8~ 6 -
forming resin from chlortrifluoroethylene monomer.
Such an intitiator/catalyst system comprises reduction,
oxidation and acceleration constituents wherein the
oxidation constituents provide free radicals for the
initiation of the polymerization of the CTFE. By way
of example, suitable reduction constituents include one
or more chemicals selected from the group which
includes; an alkali metal bisulfate and alkali metal
persulfate. Suitable oxidation constituents include
one or more chemicals selected from the group which
includes: hydrogen peroxide, and various metallic
per~ulfates, including sodium persulfate and potassium
persulfate, as well as amoonium pQrsulrite. Suitable
acceleration constituents include one or more cnemicals
s d ected from the group which includes: variable
valence metal sults such as ferrous sulphate, silver
nltrate as well as copper sulfate. Varying ratios of
these constituents may be used; i.e. the ratio of the
oxidation to the reduction constit-uents may be varied
from`l:~ to 3:1~ and the acti~ator may be included in
amounts to comprise to 1000 parts per million (nppmn?
as well as greater ~mounts.
Other processes and systems suitable for the
production of PCTFE film forming and copolymer resins
are described in U.S. Patent Nos. 2,705,706; 2,700,622;
2,~89,241; 2,569,524; 2,783,219; 2,820,026; 3,640,985;
3,671,510; 3,642,754; 3,632,847; 3,014,01. The control
., ~, ~, .
of the reaction conditions leads to the producion of
PCTFEIfi}m forming resins which ar~ wlthin the
specified ranqe of suitable ZST values.
It is contemplated that the PCTFE film forming
resin may include minor amounts, i.e. generally up to
1%~by weight of an ethylene compound containing
fluoride, including: fluorinated ~-olefins, such as
~hexafluoropropyl= e, hexafluoroi-obutylene, vinylidene
W093/06159 PCT/US92/08~
21~8925
fluoride, tetrafluoroethylene, chlorotrifluoroethylene;
fluorinated ethers such as perfluoroalkyl vinyl ethers
such as perfluoropropyl vinyl ether; perfluoroalkyl
ethylenes such as perfluorobutyl ethylene, and the
like.
The PCTFE film forming compositions which are
readily proce~sable are formed into films in accordance
with any conventionally known technique. By way of
illustration and by way of limitation these include the
extrusion of the film-forming co~position through a
flat die to form a fIat cast film, or extruding the
film through a circular die and inflating the annulus
of the fiim formed thereby to form a blown film, or by
casting or otherwise forming a billet from the film
f-osming eompo ition and thereafter skiving the billet
to~form a~fil~, as wQll a~ oth~s mQthods. Of theSe,
th-~p oduction of the film by means of a flat die and
sub-èquent casting are to be generally preferred. In
accordance with this method, the post extrusion
conditions of the fil~-for~ing co~pos$tion may be more
ade~uately controlled in accordancQ with the process
b~ing tau~ht herein. Nonetheloss, it is to bQ
und~rstood the alternate methods ~ay also be utilized
in accordance with the process being taught herein.
In accordance with the preferred embodiment, the
film forming composition is provided to an extruder
whereupon the PCTFE film forming is plastificated by
the action of heat and mechanical motions supplied by
the extruder and extruder scr~w. The pIastificated
film forming composition i5 then ~orc~d through the
film-forming ~lit of a flat die to form a film,
typically having a thickness of between about 0.01 and
lS mils thick, and preferably and most preferably
between about 0.1 and 10 mils thick. T~ereafter, the
35~ ~extruded film-forming composition is contacted with a
~ __~
WO93/~159 PCT/US92/08~
21 ~ ~ 9 8 -
casting roll whereupon the film is quiekly cooled,
quenching the erystallization of the PCTFE.
In aceordance with the present invention, the
proeess of forming films from the PC~FE film-forming
eomposition ineludes the n~ees~ary proee~s step of
rapidly eooling the extruded $ilm. Whereas in
eonventional film forming operations, a eonventional
easting roll temperature is typieally in the range of
between about 250-C and 290-C, it has been surprisingly
found by the present inventors that when the
temperature of the easting roll i~ within the range of
between about l50-C and 210-C, and maintained at a
temperature within this range, the easting roll
temperature as~ures that the rapid quenehing of;the
PC$FE film whieh exit~ the extruder ~t a temperature
of between about 500-C and 600-C oeeurs due to tfie
sudden ehange in temperature drop.
The inventor~ have al~o realized in the present
invention that the u5e of a PCTFE eomprising film
having the range of number average moleeular weights or
the zero strength time value~ outlined ~bove provides a
PCTFE film forming eomposition whieh i8 readily
proees~ble in aeeordanee with eonventional film
for~ing ~eth~ds to produee a fil~ eompr~sinq
essentially no add~tional eomonomer~ or other
eonstituent~ whieh reduee the ultimate barrier
eharacteristies of the PCTFE eomprising film.
The inventors of the pre~ent invention have also
1~ realized that the film formed from tha PCTFE film
forming eompositions deseribed above exhibits excellent
barrier eharaeteri~ties, partieularly barrier to water
vapor. Films aeeording to the present invention
exhibit a water vapor transmission rate of up to 0.03
grams of water/lO0 square inehes over ~4 hours at 100F
and 100% relative humidity for a l mil thiekness;
' '::
WO93/~159 PCT/USs2/08~
_ g _ .
preferable the films according to the invention exhibit
a water vapor transmis~ion rate of up to about 0.025
grams of water/100 s~uare inche~ over 24 hours at 100F
and 100% relative humidity for a 1 mil thickness; most
s preferable the films according to th~ invention exhibit
a water vapor tran~mi~ion rate o~ up to about 0.020
gram~ of water/100 ~quare inches over 24 hours at 100F
and 100% relative humidity for a 1 mil thickness.
While not wishing to be bound by any theory, it is
believed that such improved barrier properties are a
consequence of the absenca of large ~ounts of
additional comonomers, particularly the ab~ence of
conventional comonomer~ in excess of amount~ of 1% by
weight o~ a PCTFE film for-ing re~in which are used in
~: 15 con~unction with PCTFE polyuers, p~rticularly
vinylidine fluoride and/or tetrafluorosthylene w~ich
reduce the barrier propertie~ of a PCTFE film, and
further, due to the hi~hly cry~talline nature of the
PCTFE film formed from the PCTFE described above in
~ 20 accordance with the proce~s ~teps outlined above~ The
: inventors have attained excellent results with the
preferred composition~ ~ccording to the pre~ent
invention, wherein thQ film forming resin composition
consi~t~ e~entially of a h~mopoly~ar resin of P~TFE
and no additional comonomers.
The formation of the fil~ from the PCTFE
composition taught b~ th~ pre~ent invention by means of
a conventional film casting technigues are generally to
be preferred as such production method~ allow for the
formation of films which are ultimatQly useful for
forming one layer of a multi-layered film structure.
As will be realized by those skilled in the art, films
herein having improved water vapor barrier properties
may be combined with one or ~ore other films featuring
-; 35 of the desirable characteristics, i.e., physical
:
, ~ ,
=..
WO 93~K159 PCI'/US92/08064
392S - lo -
strength, thermo-formability, color, appearance, in
forming an article.
Exemplary films which may be used in conjunction
with the PCTFE films of the present invention to form
multi-layer film structures or alternately known to the
art as film laminates include one or more of the
following films or film forming compo3itionC
acrylonitrile butadiene-~tyren~,
rubber modified acrylonitrile methyl acrylate
copolymer,
cellulostic films including cellulos~ acetate,
cellulose triacetate,
cellulose acetata butyrate,
celluio~e propionate,
ethyl cellulose,
cellophane,
fluoropl~tic f-ilms including
ethylenechlorotrifluoroethylenQ copolymer (ECTFE),
ethylenetetrafluoroethylene copolymer ~ETFE),
fluorinated ethylene-propylene copolymer (FEP),
perfluoroalkoxy (PFA),
polychlorotri~luoroethylQ~e copoly~r~ (PCTFE),
polytQtrafluoroethyl~ne (P$7FE~
polyvinylfluorids (PVF),
poly~inylidene fluoride (PVDF),
iono~er ~
polyamid~ f~lms including unoriented, mono~xially
oriented, or biaxially films, including films including
nylon~6, nylon 12 as well as polyamide copolymers and
blends of each of the above,
polybutylene,
polycarbonate (PC),
polyalkylene terephthalate, including,
polybutylene terepthalate (PBT),
WOg3/06159 PCT/US92/OX~
21~92S
11 --
polyethylene terephthalate (PET), as well as films
comprisinq polyester copoly~er, particularly those
copolymers comprising polyethylene-terephthalate
with at leas~ one additional comonomer, including
but not li~ited to tho~e known to th~ art as "PET-
G" films and co D arcially markated und~d the n~me
KODAR~ by the Ea~tman ~odak Co.,
polyethyl~nQ ~nd polyethylen~ copolym~r fil~s including
low density polyethylene (LDPE),
m~dium d~nsity polyethylene (NDPE),
high density polyethylene ~HDPE~,
ultr~high mole~ular weight polyethylene (UHMWPE),
ethylene-vinyl acat~te ~opolymers ~EVA),
` polyimide films,
polymethylmethacrylate films, (both ~tandard" and
¦ ~type A")
polym~thylpant~ne,
polypropylene (PP) films including ca3t, unori nted,
monoaxially ori~nt~d, or bi~xially oriented,
polystyrsne,
polyureathane,
polyvinyl chloride (PVC),
sulfone poly~r film t
v~nyl chlor~d~-~cet~te copoly~er,
vinylidene chlorld~ vinyl chlor~d~ fil~,
vinyl nitrilQ rubber ~lloy films, a~ well a~ others not
particul~rly not~d here.
The PCTFE co~pri~ing fil~s of the present
' inven~ion are be co~bined wit~ ~u~h other films in
accordance with conventional mzth~ds, including
coextrusion of the film~ to ~orm a la~inar f~lm
structure, or by lamination of the fil~ into a l~minar
film structure, with or without the use of a
composition which acts to form a "tie layer~ between
` 35 the PCTFE comprising film and the other film or films
:~
WO93/06l59 PCT/US92/08~
~ ~ 5 9 ~ 12
used to form the laminar film structure. Such
compositions which act as "tie layers" may be any of
those conventionally known and used, a~ well as other
materials which provide adhe~ion of the PCTFE
comprising ~ilm with at least one other film to form a
laminar film structure. Of these methods, lamination
of the polytrichloroethylene films is preferred, a~
`~ such offers the widest range of laminar film
structures.
In one embodiment, the PCTFE comprising film
taught herein may be incorporated into a multi-layered
film structure ~uch as may be achieved by the
lamination of the PCTFE comprising fil~ with one or
more ther oplactic films which are ther~oforoable.
~ 15 Particularly, polyvinyl chlorid~ and polyethylene
`'A`~ t r-pthalate filos and copolyesters comprising
polyethylenQ terephthalte may be mentioned h~re. The
ben ficial feature of the two or more fil~s may be
optimized to provide a suitabl~ packaging container.
~; 20 ay way of example, a PCTFE compri~ing film may
~ contribute excellent vapor barrier characteristics and
-~ when combined with a PVC fil~ or alternatively a
polyethylene terephthalate film which provides good
, ~
` phy~ical strength characteristics, a packaging
structure prov~ding the benef~ts of both such the
films, good water vapor transmission barrier properties
and good physical strength, may bQ produced. Further,
in ~uch a packaging container, the PCTFE co~prising
,~ film may be oriented to contain and contact the
material, such as a foodstuff or medicament, w~ile the
~ PVC or polyethylene terepth~late may form the outer
-~ layer of the laminated and th-rmoformed film ~tructure.
The P FE fi}ms may be laminated to other
polymeric films in accordance with any suit~ble
6."~
.o~
j~
W093/~1~9 PCT/U592/OX~
2 i l ~ 9 2 ~
- 13 -
technique which includes the conventionally known
techniques of extrusion lamination wherein the two or
more films are coextruded and the extruded films are
combined to form a multi-layer film ~tructure; by
S adhesive lamination where two or more films which have
been formed by any technique ~re provided with an
intermediate layer of an adhesive ~ateri~l or
con~tituent which forms a ~tie layer~ to thereby
produce the multilayer film.
The films, whether comprising a single layer of
the PCTFE comprising f~lm for~ing composition or a
~ulti-layer film, may optionally be ~tretched or
~; oriented in:any direction if 80 desired. In such a
~tretching operation, the fil~ may bo stretched in
. ~: 15 either the direction coincident with the direction of
OV_ nt of the filo being withdrawn from the ca~ting
roll, al~o referred to in the art a~ the ~machine
`direction~, or in a direction which is perpendicular to
: the machine direction~ and referred to in the art as
; 20 the "transver~e direction~, or in both the machine
` direction and the transverse direction. Tt is to be
understood th~t in embodiments where the PCTFE
comprising film taught herein i~ to b~ u~ed in a
multilayer film structure, that les~ than all of the
film~ within a multilayer ~tructure which ar~ used to
produce such a structure may be oriented, such as might
be accomplished by the lamination of an oriented PCTFE
comprising film to an unoriQnted PVC film by the use of
an intermediate tie layer, as well as the reverse oase,
~;: 30 wherein an unoriented PCTFE comprising fi.l~ i8
minated to an orientod PVC film. Further, it is to
be appreciated that film~ may b~ sub~octed to
orientation re~ulting from a stamping or ~olding
process wherein the film is heated and deformed into a
'~
`' :: ~ '
WOg3/06159 PCT/US92/08~
~ ~ ~L () 9 ~J i
- 14 -
three dimensional structure; the regions of the film
which are defor~ed undergo orientation
The multi-layer f ilm8 formed by any of the above
methods ~ay ulti~ately be of any thickness desired and
includ~s tho~ which have thickn~sse~ le8i than 100
mil~ A~ i~ known to the art, a ~ 8 a co~on unit
equivalent to 0 001 inch and i8 typically used to
;~ de~cribe fil~ th~cknesse~ Preferably, the fil~s have
a thickn~ss in the range of about 0 01 ~1 and about 10
mils; most pr~ferably the films have a thickness of
between about 0 01 ~il~ and 1 0 ~il8. While ~uch
thickn~-es ar- pr-f rred à~ providing a readily
flexible fil~, it is to be understood that other film
th$ckne~se- ~ay be produced to ~atisfy a particular
5~ need and~yet fall wlthin the present invQntion's scope;
sUch thlckn s~e~ which are conte~plated include plates,
; thlck fil~s, and sheets which are not readily fl~xible
at roo~ t~perature (approx 20 deg C)
The fiI~s taYght ~n the pre~nt invention are
particularly usQful ror~rorning packaging or containers
structures which requir- low water vapor trans~ission
prop~rties The~e may be ca~t article~ or th~r~o-
form~d articles such as those which ~ay bQ formed from
a ~ilm or sheQt of the film-forming composition which
25 iB "stamped~ by hot di~, by a ~vacuu~ drawingn, a
technigue al50 known a~ ~e~bossinq~ wherein a film or
~ t of th~ fil~-forming composition i~ defor~ed by
'7'`~ the u~e of a vacuum, tand optionally ~ay be al80
.
simultaneou~ly mechanically deformQd1 thereby
effectively deforming the film into a tbrQQ-dimensional
;~ shape In a preferred method, the film or shQet
comprising the PCTFE film~is for~ed by pres~ure
forming the fil~ by the u~e of a heated die wherein the
fil~ i~ contacted~with`a he~ted die ~nd under the
3~5~ ~inflù-nce of~beat and pres~ure, defor~ed to for~ a
W093/06159 PCT/US92/OX~
- 15 ~ 92S
three-dimensional shape. An alternative packaging
structure within which the present film-forming
composition may b2 used are pouches or bags which may
be formed from two pieces or sheets o$ films which are
S ~oined to one another 80 to form a containment space
between the two sheets or films suit~ble for the
containment of solid~, liquids and/or gases. The film-
forming compositions may also be used to form a
storage vessels or containment vessels, therefrom i.e.,
jars, bottles, and the like which may be sealable,
wherein the film-forming composition taught by the
instant specification may form at least one layer of
the ~aid structure.
- one particularly useful article ar~ packaging
materials asfioci~ted with medicaments and
~ pharoac~utical compositions which are provided in
; either a pill, capelet or capsule form. Such a
packaging structure is known to the art as a ~blister~
pack. ~lister packs conventionally comprise at least
two elements, a first sheet of a thermo-formed multi-
layer fîlm which has been stamped with at least one,
but more generally a plurality of indentations which
form "receptaclesn. Such indentation~ extend out of
the plane of the film (which may be generally be
con~idered to be two-dimensional) to form a three-
dimension~l shape. Such shapes form individual
re~eptacle~ ~re ~uited for th~ retention o~ a pill,
cap~ule, or capelet. A furthsr, second s~alant sheet
is generally layered in reqister with the fil~ sheet
which seals the individual re~OEptacle~ form~d within
the first sheet and containing the pharmaceutical
composition. Typically, the ~econd sealant sheet is a
metallic sheet sucb as aluminum foil or metallized film
which provides good strength and low water ~por
transmission and/or odor permeability. Further, a use
:~
~ .
~::
WOg3/06159 PCT/US92/08~
9~ 16 -
of a metal or metallized sheet as the sealant sheet may
be desirable as such materials being substantially
opaque provide a backing with the f irst sheet
containing the indentations and a rapid means of visual
inspection by which it may be readily determined which
of the contents of the receptacles have been removed
from the said packaging structure. In an alternative,
such a second sealant sheet may be a sheet comprised of
a fibrous material such as a paper product, or of a
; lo polymeric film or sheet which may or may not be colored
or which alternately may or may not be opague.
The content~ of the receptacles which are retained
within a receptacle of a multi-layer film sheet and a
seal~nt sheet ~ay be removed by forcing the contents
tbrough tbe seal~nt sheet so to burst the sealant sheet
nd allow tbe removal of the content~, or tbe sealant
sbeet may be at least partially peeled so to separate
,
the multi-layer film sheet from the sealant sheet and
; allow access to the contents.
The film~ of the pre~ent invention may be imparted
~ wit~ à conventional coloring agent or a dye or pigment
- ~ so to impart a color to the l~minat~d film structures,
or alternately to render the f~lm structures
substantially opaque. Any conventional coloring agent
or a dye or p~g~ent which is appropriate for use in the
~ilms may be us~d. It may be desirable in particular
a~pects to provide a coloring agent to one of the films
forming the laminated film structure, by way of example
I to the PVC, PET or polyethyl~na copolymer film with a
coloring agent, which may be selected to act aa a
filter to block the tran~mi~sion of particular
radiowave frequQncies, particularly those within the
visible, ultraviolet and infrared spectrum bands which
~if transmitted to the material such a~ a pharmaceutical
'~ 35 composition, medicament or foodstuff contained within a
,~
.. ,~
.,~:
W093/06~59 PCT/U~92/08~
- 17 - 2 1 1 ~ ~ 2 ~
structure formed from the laminated film structures
taught within would act to degrade th~ said materia~.
In addition to the blister pack ~heet which is
used to provide a structure for the packaging and
retention of medicaments and pharmaceutical
compos~tions, it is also to be understood that such a
blister pack provided by the pre~ent invention may be
used for the containment of other edible compo~itions,
such as foodstuffs (including liquid~ or gelatinous
materials), as well as composition~ or articles which
are not normally edible. Examples of such materials
include, but are not limited to any ~rticle or
composition which may be benefici~lly stored in a
structure aæ taught herein, such a~ paints~ dyes, inks,
liquid slurries, agueou~ slurr~eQ, or any article of
:~ - manufacture which may comprise one or more of ~uch
materials. Further it should be recognized that the
multi-layer film may be t~ermoform~d into a container,
such as a gla~, cup, bowl, dish, or other vèssel
suitabl~ for the containment of an ~dible or imbibable
co~position, i.~., foodstuffs, medicam~nts,
ph~rmaceutical compos~tion~ or alt~rnat~ly, an inedible
composition, i.e. article~ of manufacture, liquids,
slurrie~, g~latinou~ composit~ons, ~uch ~8 are
pre~ntly known a~ a ~singlQ u~e container~. In one
~uch Qmbodi~ent of such con~tructions, ~t i8
conte~pl~ted that a film di~similar to ~he PCTF~
compr~sing fil~ taught herein would be in contact with
the edible or imbibable composition, while th~ PCTFE
compri ing film would be used a~ a further layer of the
thermofor~ed article. For ex~mple, one ~uch article
may be formed from a multilayer film comprising a
polyethylene terephthalate film layered in register
wi_h the PCTFE comprising film of the present invention
wherein the multilayer film is deformed to form an
,
~:
WOg3/06159 PCT/US92/08
2 ~ ?~5 - 18 -
arti~le such as a small cup ~o that the interior of the
cup which is to ultimately contact the foodstuff to be
retained in the cup contacts the polyethylene
terephthalate film. In an alternative embodiment, the
S PCTFE comprising film of the present invention u~ed in
forming a multil~yer film may al80 be used to form an
article such that the PCTFE-comprising film will
ultimately contact the foodstuff, or pharmaceutical
composition or medicament which is placed in the said
10 Cup.
The determination of the physical characteristics
of the films may be determined using any commonly known
testing procedure, including the protocols defined by
; the American Society of Testing M~teri~ls, including
but not limited to those design.~ted under the protocols
~; ` of ASTM D 882-83 ~St~nd rd Testing Nethods for Tensile
` Properties of Thin Plastic Sheetingn. PrefQrably, the
ples are ev~luated in both thQ machine direction and
the transver~e directions. In accordance with the
protocol of the ASTN D 882-83 tests, the ten~ile
modulus is reported in unit~ of pounds per square inch,
p~in, the ten~ile yi~ld ~trength is reported in units
i~
` ~ of psi, the yi~ld elongation i~ reported in units of
percent ~, the ultimate t~nsil~ strength is reported
in units of p~i, and the ulti~ate ten~ile elongation is
reported in units of ~ and the Elemendorf Tear Strength
reported in terms of gram8. The direction of the
test measurement was relative to the direction of the
film with ~MD" indicative o$ machine direction
orientation, and "TDI indicative of transverse
direction~ orientation. The barrier characteristics
of the film samples were run on s~mple sheetfi of 100
square inches at 100F and 100% relative humidity on a
Mocon Permatran Model W600 testing device in order to
determine the amount of water which permeated the film;
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ynD~ohlD PCT/US92/08~
- 19 - 21 i8 g~ 5
units for this value are (grams of water x mil of film
thickness/100 inch2/day).
The invention i~ more Qa6ily understood by
reference to specific embodiment~ which are
representative examples according to the teachings of
the instant invention. It mu8t be understood however,
that the specific embodiments discu~ed herein are
provided only for the purpose of illustration, and not
by way of limitation, and it is to be further
under~tood that th- invention my be practiced otherwise
than specific~lly described and yet be within the
inventive acope.
I "~
I ' :~
Fila sa~ples were producod of PCTFE films in
accordance with the de~cription dQ~cribed herein, as
wall as plural ~ilm~ which wer produc~d from PCTFE
copolymers, including those which comprised ~inor
~;1 amounts of either vinylidine ~luoride or
~ 20 tetr~fluoroethyleno which ara known to the art. The
.;~ fil~s were te~ted for their water vapor txan~ ion
~ rates, "WVTR~ on th8 Mocon P~rmatran Model W600 tester
; and their physical char~cter~ tics in accordance with
th~ t~sting protocol of ASTM D 882-83.
- 25 The f~lm~ were produced in accordanc~ with the
~ollowing general proce~sing conditions: the (or
copolymer in tha case o~ the comp~r~tiv~ axampl~s) was
provided to the faed inlet of a 3 1/2 inch extruder
with a general purpo~e mixing screw having a length to
diameter ratio, ~L/D" o~ 24/1. The feed ~nlet was
about 560F, and the extruder was maintain~d at a
temperature o~ approximately 550~ ~cros~ the length of
the barrel. The pressure in the extruder was about
4000 psi. The extruder was operated to produce
i~ 35 approximately 80 lbs/hours of the composition; the
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~Dg3~061Sg PCT/US92/08~
~ 9~ 5 - 20 -
serew rotational speed was approximately 18 rpm. The
extrudate exiting the extruder was then foreed into a
conventionl film forming die head of the "eoathangerN
type, whieh had a die gap of 0.035 inehe~ (35 mils),
5 and a width of about 40 inche~. The di~ head was
~aintained at a temperature of 620-F; the rate of film
produetion or ~line ~peed" was approxi~ately 65
feet/min. The extruded film wa~ eontaeted with a
; easting roll whose temperature was maintained at
10 approx. 150F, or ~s is noted in some instanees at
about 270-F. A film having a final width of about 40
inehe~, and a thiekness of approximately 0.5 mil was
produeed therefrom. The partieular film eompositions
~ .
are shown on Table 1, a~ounts of tetrafluoroethylene
15 ~(~TFE~) and/or vinylidine fluoride (~V~2~) whieh were
used as eomono~ers are listed with their respeetive
; w~ight pereentages of eaeh for re~peetive film forming
eompositions, as well as the ZST value~ for eaeh
eomposition. Barrier eharaeteri~ties of these film
20 eomposition~ are shown on Table 2, and phy~ieal
:
~ properties of the film eomposition~ are shown on Table
;~ 3.
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As may be seen from Table 1, the film compositions
of the comparative examples Cl through C6 included
amounts of comonomers in the composition of the film
S forming resin. The film compositions according to
examples 1 - 6 consisted of a homopolymer resin
comprising no additional comonomers as are included in
the compositions of the comp~rative ex~mples Cl-C6.
The films formed in Examples Cl-C6~ 1-2 had a film
thickness of O.S mil and films 3-6 had a film thickness
of 0.6 mil; values on Table 2 for 1 mil thick films are
-~ normalized for that thickness from the values for the
0.5 mil film samples. All of the films were tested
using the Mocon Permatran Model W600 testing device at
100F for WVTR value~.
.~
'-~ The results of the physical testing of the film as
~`
;~ sumnarized on Table 3 show improvements of the
inventive co~positions over films of the prior ~rt; the
~ films of Examples 1-6 illustrate increased barrier to
"~ 20 water resistance in films comprising no comonomers
`~ while simultaneously preserving good physical
propertieE . The inventors had also found that the
films of C1-C4 ea~ibited very poor ~ oformability as
opposed to the films of 1-6 which were readily
th@rmoformable.
It will be appreciated ~hat the instant
specif ications and examples set f ort~ herein are by way
of illustration and not limitation, and that varioùs
~ modifications and changes may be m~de without departing
¦~ 30 from the spirit and scope of the present invention,
whose limitations are bounded only by the append~nt
clai~s.
