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The present invention relates to a method of forming
thermoplastic tubular containers and, more specifically, to a
method for forming a head on a tubular sleeve to provide a neck
portion of a thermoplastic tubular container.
This application is related to co-pending Canada application
Serial No. 536,141 filed May 1, 1987, and entitled ~Method For
Producing Tubular Plastic Containers", in the names of George H.
Holoubek, John J. Rhoades, and George P. Whitaker, assigned to
the present assignee.
Thermoplastic tubular containers, especially collapsible or
squeezable containers, have continued to take over an increasing
share of the container market from metallic tubes. Such
thermoplastic tubular containers are extensively used in
packaging of cosmetics, medicinal preparations, shampoos and
other products. With the increased development of multilayer or
laminated tubes having oxygen barrier properties, that resist
oxygen permeation, ~urther increases in packaging of
pharmaceutical products and of foodstuffs in thermoplastic tubes
are occurring.
An advantageous method for forming such containers involves the
extruding of a hollow tube and then cutting the tube to desired
lengths and forming a head or neck portion to close one end of
the resulting tube. The other end is retained in an open
condition for filling the container with the goods to be
packaged, followed by sealing of the open end to provide an
integral sealed tubular container.
A known method for forming collapsible plastic tubes with neck
portions, known as the "Downs" process, is described in U.S.
3,047, 910. As described therein, thermoplastic tubular
containers are fabricated by placing a thermoplastic tubular
member, or hollow tube, into a forming collar and forcing a cut,
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molten disc into an open end of the tubular member. The latent
heat of the molten disc is sufficient to weld the peripheral edye
of the disc to the inner wall of the tubular member and thus form
an end closure for the tubular container. As described, pressure
is exerted through the interior of the tubular container to the
sealed end closure to shape the latter to a desired contour. The
preferred means for applying pressure to the sealed end closure
is through the use of a mandrel that is inserted through the open
end of the tubular member. Air pressure, or vacuum, are not
suggested for forming the contour of the sealed end closure,
although it is suggested that air under suitable pressure or a
reciprocable flat end mandrel may be admitted interiorly of the
tubing to assure that a flat end closure is not distorted upon
cooling and remains desirably flat.
While the above-described process has been suitable for forming
headed portions or necks on collapsible tubular containers,
complicated tooling is required to force the plastic dlsc to
conform to a mold cavity, necessitating high tooling costs and
subsequent upkeep. Also, with the use of compression molding of
the headed portions, massive hydraulic equipment is used, adding
to capital cost and maintenance costs. In addition, relatively
thick discs are needed where compression molding is used which
increases costs and adds to scrap produced. Not only are cost
considerations prevalent with the use of such a process, ~ut the
process is limited with respect to the type or shape of head
produced by such a compression molding system. Such a process is
not, for example, readily adaptable to formation of heads on
tubes where the heads have multiple orifices or complex/head
configurationsO
one modification of the above-described process for use in
forming multi-layer or laminated collapsible thermoplastic
tubular containers is described in U.S. 3,962,006. In that
process, a laminated film is used to form a thermoplastic sleeve
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having an impermeable layer and a molten disc also having an
impermeable layer is welded to the interior wall of the laminated
thermoplastic sleeve. A pressing operation is used to form a
head member on the tube, the pressing operation using a female
mold and a core which interiorly supports the laminated
thermoplastic sleeve.
The present invention provides an improved method for forming a
thermoplastic tubular container whereby a head can be readily
formed which has a predetermined complex head configuration.
The present invention also provides a method for forming a
thermoplastic tubular container that uses a molten disc to seal
the end of a tubular sleeve but does not require the massive
hydraulics presently used to compression mold a head on the tube.
The present invention also provides a method for forming a
thermoplastic tubular container that uses a molten disc to seal
the end of the tubular sleeve which enables the use of a thinner
shoulder, relative to compression molded heads, thus increasing
manufacturing speed, lowering material costs, and reducing scrap.
A method for forming a thermoplastic tubular container, wherein a
molten plastic disc is secured within the confines of an open end
of a hollow tubular element, with the latent head of the molten
disc welding the disc to the inner wall of the hollow tubular
element to seal the same, includes the use of an internal sealing
mandrel to seal only a shoulder thereof, and then forming the
thermoplastic disc, while still in a moldable state, to a mold
configuration. The internal sealing mandrel, having a sealing
head on the end thereof, is inserted into the other open end of
the hollow tubular member, the sealing head having a first
shoulder which traps the periphery of the disc between said first
shoulder and a second shoulder about the periphery of a mold
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cavity. Pressure on tha sealing mandrel is applied only to form
a seal of thermoplastic material between the first and second
shoulders, and forming of the thermoplastic disc, while in a
moldable state and while only the seal of thermoplastic is in
contac~ with the sealing head, is effected by either applying a
fluid pressure against the surface o-f the thermoplastic disc
confronting the sealing head, or applying a vacuum to the surface
of the thermoplastic disc opposit~ the surface thereof
confronting the sealing head, or both. So fonming of the disc,
while in a moldable state, causes the disc to conform to the
predetermined shape of a mold cavity to form a closed end wall on
the tubular container having said predetermined shape.
Thus according to one aspect thereof the present invention
provides a method of forming a thermoplastic tubular container
wherein a molten plastic disc is secured within the confines of
an open end of a hollow tubular element and allowing the latent
heat of the molten plastic disc to weld the peripheral edge of
the disc to the inner circumferential wall of the tubular element
to seal the same, the improvement wherein: An internal sealing
mandrel, having means for in~ecting a fluid therethrough, is
inserted into the other end of the hollow tubular member, the
internal sealing mandrel having a sealing head on the end
thereof, the sealing head having a first shoulder thereabout;
positioning the hollow tubular element and disc within a mold
cavity defining a predetermined shape, with a second shoulder
about the periphery of the mold cavity complementary with said
first shoulder; applying pressure on said sealing head to trap
the periphery of said thermoplastic disc only to form a seal of
thermoplastic material between said first and second shoulders,
such that only the portion of the thermoplastic disc not sealed
between said shoulders is subject to forming into the
predetermined shape of said mold cavity; and forming said portion
of said thermoplastic disc, not trapped between the complementary
first and second shoulders, by injecting a fluid through said
5369L
fluid injecting means of said internal sealing mandrel against
the surface of said disc confronting said intQrnal sealing
mandrel, while the same is in a moldable state, and while said
periphery of said thermoplastic disc is in contact with said
sealing head, to cause the same to conform in shape to the
predet~rmined shape of said mold cavity to form a closed end wall
on said thermoplastic tu~ular container having said predetermin~d
shape. Suitably said means for injecting fluid through said
internal sealing mandrel comprises an internal sealing mandrel
having a sealing head with an axial passageway therethrough, and
means communicating with said passageway to inject fluid
therethrough. Desirably said fluid is pressurized air. Suitably
said forming of said thermoplastic disc is effected by injecting
a fluid through said internal sealing mandrel, a vacuum is
applied to the surface of said disc oppQsits the surface
confronting said internal sealing mandrel. Desirably said fluid
is injected through said internal sealing mandrel at a pressure
of between about 5 to 140 pounds per square inch and said vacuum
is in an amount of betw~en 10 to 30 inches. Preferably sald
fluid is air.
In one embodiment of the present invention said hollow tubular
element and said disc comprise a laminate of a plurality of
layers of material. Suitably at least one of said layers is a
barrier material. Desirably said barrier material is comprised
of an oxygen imperrneable material.
In another aspect thereof the present invention provides in a
method of forming a thermo~lastic tubular container wherein a
molten plastic disc is secured within the confines of an open end
of a hollow tubular element and allowing the latent heat of the
molten plastic disc to weld the peripheral edge of the disc to
the inner circumferential wall of the tubular element to seal the
same, the improvement wherein: an internal sealing mandrel is
inserted into the other end of the hollow tubular memberr the
internal
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sealing mandrel having a sealing head on the endthereof,the
sealing head having a first shoulder thereabout; positioning the
hollow tubular element and disc within a mold cavity defining a
predetermined shape, with a second shoulder about the periphery
of the mold cavity complementary with said first shoulder;
applying pressure on said sealing head to trap the periphery of
said thermoplastic disc only to form a seal of thermoplastic
material between said first and second shoulders, such that only
the portion of the thermoplastic disc not sealed between said
shoulders is subject to forming into the predetermined shape of
said mold cavity; and forming said portion of said thermoplastic
disc, not trapped between the complementary first and second
shoulders, by applying a vacuum to the surface of said disc
opposite the surface confronting said internal sealing mandrel,
while the same is in a moldable state, and while said periphery
of said thermoplastic disc is in contact with said sealing head,
to cause the same to conform in shape to the predetermined shape
of said mold cavity to form a closed end wall on said
thermoplastic container having said predetermined shape.
Suitably said vacuum is in an amount of be-tween about 10 to 30
inches.
In a further aspect of the invention a method of forming a
thermoplastic tubular container wherein a molten plastic disc is
secured within the confines of an open end of a hollow tubular
element and allowing the latent heat of the molten plastic disc
to weld the peripheral edge of the disc to the inner
circumferential wall of the tubular element to seal the same, the
improvement wherein: an internal sealing mandrel is inserted
into the other end of the hollow tubular member, the internal
sealing mandrel having a sealing head on the end thereof, the
sealing head having a first shoulder thereabout; posi.tioning the
hollow tubular element and disc within a mold cavity defining a
predetermined shape, with a second shoulder about the periphery
of the mold cavity complementary with said first shoulder;
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applying pressure on said sealing head to trap the periphery of
said thermoplastic disc only to form a seal of thermoplastic
material between said first and second shoulders, such that only
the portion of the thermoplastic disc not sealed between said
shoulders is subject to forming into the predettermined shape of
said mold cavity; and applying a fluid pressure aga1nst the
surfacet of said disc confronting said internal sealing mandrel,
while at the same time applying a vacuum to the surface of said
disc opposite the surface confronting said internal sealing
lo mandrel, while the disc is in a moldable state, and while said
perlphery of said thermoplastic disc is in contact with said
sealing head, to cause said portion of said thermoplastic disc,
not trapped between the complementary first and second shoulders,
to conform in shape to the predetermined shape of said mold
cavity to form a closed end wall on said thermoplastic tubular
container having said predetermined shape.
The present invention will be further illustrated by way of the
accompanying drawings in which:
Figure 1, containing figures lA through lF, illustrate the
conventional process for formation of a head on a tubular element
by an internal forming mandrel, such as described in U.S.
3,0~7,910;
Figure 2 shows a sealing mandrel useable in the present method
within a hollow tubular element having one end, closed with a
disc, positioned ad~acent a mold cavity;
Figure 3 illustrates the application of pressure to the sealing
mandrel with insertion of the lower portion of the hollow tubular
element and the moldable disc within the mold cavity and
application of fluid pressure therein to form a head;
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Figure 4 shows a sealing mandrel within a hollow tubular element
having an end, closed with a disc, positioned adjacent a mold
cavity for use with application of a vacuum to form a head,
Figure 5 illustrates the application of pressure to the sealing
mandrel with insertion of the lower portion hollow tubular
element and the moldable disc with tne mold cavity and
application of a vacuum to form a head;
Figure 6 shows a sealing mandrel usable in the present method
within a hollow tubular element, having one end closed with a
disc~ positioned above a mold cavity prior to application of both
fluid pressure and vacuum to form a head;
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JUI`1-16-'~7 TUE 15:32 Irl: Pt~W f:l~`lD K PGH TEL NO: d,lZ 2~31 18Zl #042 P0~
j ~Lgure 7 illu~t~tes the applIcatIon of pressure to
¦the sea1in~ m~ndrel with insertion of the lower portion of t.h~
h~llow tubulAr el0men~ and the mold~ble di6c within ~he mold
l cavity and the appl~cation of both fluld pre~sure and vac~um
¦ thereto to form ~ head;
Fi8ure ~ shows a tubula~ ele~ent ~nd disc posi~Ioned
adjacent a mold cavity ~or fnrmnt~on ~f ~ ~ul~us head;
~ igu~e ~ illustrates ths applicatlon o~ fluid p~essure
l to ~orm a bul~o~s he~d;
¦Fi~ure 10 illus~rates a eont~in~r having ~ bulbous
he~d, formable by the present me~hod;
~i~ure ll ~llustrate~ the applicatLun o~ ~luid
pre~sure ~o form an ~ppllcaeor-type t~e~d a~cording to ~he
pr~sen~ method; ,
~igure 12 ill~strates a c~ntainer having an applicato~
head, f~rm~ble by t~e present method9
Figure 13 illus~ra~es the ~plic~tion of rluld pre~-
sure to form a novelty he~d in the ~hape o~ ~ clown's head
~ccordin~ to ~he p~esent method;
Figu~e 14 illustrates a ~ont~iner hAving ~ novelty
head, such as a clown's head~ formable by the p~esent method;
Fig~re 15 illustr~tes t~e Application of fluid
pres~ure to form ~ twi~t-of~ head ac~ordin~ to the present
method; and
: 25 Fi~ure 16 Illustr~tes ~ ~ont~iner h~ving A ~wist-off
hea~ or~a~1e by ~he present met~o~.
~t~
The present met~od is ~n improvemen~ Dv~r conventional
processes ~or formin~ a head ~r closed ~nd ~Ub~lhr container,
JuN~ iæ7 TUE 15:33 ID: PtIW ~NDI<P~H TEL NO: 412 281 18c1 ~ P09
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¦and enables the fo~-na~ion of un~onvention~l heads of vario~s
¦ shapes. A.s i~ known, conventional p~ocesse~, such ~s the "~o~ns"
pro~Qss described in U.S. 3,047,910 use ~he latent he~t of a
l molten the~oplastic dlsc to seal the per~phery of the disc to
the inner clrcumferential wall of a tube ~o close the end
~hereof. Figures 1~ throu~h lF illus~rate such a conventional
process. As illustrated therein, ~ hollow tubular element 1, or
~leeve, of ~ ther~oplastic m~terL~l is formed) such ~s by
l ext~uding a tube o~ rmoplastic m~terial and cutti~g desired
lengths~ as illustr~ed in Figure lA. The hollow tubular element
i5 then conveyed to a punch st~tion (~i~ure lB), havlng
punrhes 3, while suppor~ed on ~ formin~ mandrel 5 that has a
support membe~ 7, ~e~d portion ~, ~nd protruslon 11 ther~on~ The
l ~upported holLow tubular elemcnt is posit~oned above a molten
l strLp or fllm 13 of a ~hermoplas~ic materi~l suppor~ed on a ~ase
15. Upon aCtiV~tiQn a~ the pu~ch station, the punch 3, sucb as
: by lowerin~ ~he sa~e as lndic~ted by the arrow in Fi~ure i~,
mec~anic~lly cuts through the molten thermoplastic strLp 13~
forming #nd pickln~ up ~ circular ~lu~ or disc 17~ The molten
~hermoplastic disc 17 is then in con~act ~ith ~he bottom e~e of
the hollo~ tubul~r element 1, where the l~tent h~ad ~rom the
disc 17 ~hen p~rtlally melts t~e ma~lng edge of the hollow
tub~lflr element 1~ formlng a natural ~eld lg be~ween the
perip~eral ed~e 21 of the dlsc i7 and inner circ~mferenti~l w~11
Z5 73 o~ the tubulAr element 1 to seal t~ s~me (Figure lP1, to
pro~ide a preform 25 for sub.sequent ~orming. The preform 25
(~i~ure 1~) is then transpor~ed to ~ molding s~tlon where
hydraulic pressure i~ ap~lied ~o the ormin~ mandrel in a mold
fo~. As illust~a~ed in Fig~re lE, the preform ~5 supported by
~2~
forming mandrel 5, is positioned above a mold form 27 having a
cavity 29, with walls 31 thereabout. The mandrel 5, upon
pressure being applied thereto, as indicated by the arrow (Figure
1) compresses the molten disc 17 against the walls 31 of the
cavity 29 in the mold form 27, forciny the thermoplastic to
conform to a head 33 in the shape of the mold space between the
forming mandrel head 9 and the protrusion 11 and the walls 31 of
the mold cavity 29. The external tooling is constantly cooled so
that, as the formed disc 17 is compressed into the desired shape,
the thermoplastic "sets up", thus permanently forming the shape
of the thermoplastic tube head.
This prior art process, as illustrated in Figure 1 has
been very successful in formlng thermoplastic tubular containers,
but contains some drawbacks. The forming mandrel must be capable
of forcing the thermoplastic disc into the required shape and
thus limits the shapes that can be produced. Tooling costs and
subsequent upkeep costs are high, while manufacturing speeds are
not as high as are desirable. Massive hydraulic systems are also
required in order to provide the compression forces necessary to
mold the head. In addition, exotic shaped heads or novelty
shaped heads are not readily produced using such a compression
type forming mandrel.
By use of the present method, these disadvantages are
removed. The present method uses either fluid pressure, vacuum,
or a combination of fluid pressure and vacuum to form heads on
tubes where an internal sealing mandrel is used only to provide a
seal about the periphery of the head formed.
Referring now to Figures 2 and 3, one embodiment of the
present process is illustrated wherein fluid pressure alone
JU~ 16-i~7 TUE 1~,:34 ID: PMW Rl`ID K PEiH TEL NO: 41~ 2~1 1821 #048 Pll
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is used to form ~ head. A hollow tubular el~ment or sleeve 1 has
a rnolten ~is~ 17, with the peripheral edge 21 thereof welded to
the inn~r clrcumferen~ial wall 23 of t~le hollow tubul~,r mem~er,
and ~n internal sealing mandrel 35 i~ Inser~ed ~herein, ~he
intern~l se~ling m~ndrel 35 having a sealing head 37 on ~he end
th~reo~ said se~lin~ he~d havin~ a first shoulder 39 about th~
~;urfaee thereof con~rontlng s~id disc, and ~ conduit 41 thereon
which communic~es wlth ~ pAss~eway 43 that ext~n~s thro~lg~ the
sealing heatl 37. The hollo~ tub~llar element 1, wit~ t~e disc 17
still in ~ mol~ahle s~a~e, is positione~ adjacent ~ rnold form 27
which may be ~n integr~l Imit or formed of mating sections 27
and 27i~ havin~ a ::avity ~9, wl~h w~lls 31 About ~he cavity~
with one sectlorl h5 of the wall 31 ~lavlng a se~ond shoulder 47
thqt i9 complemen~ary with the first shoulder 39 on the se~lin~S
head 37 o~ the sealing mand~el 3~. A source of pressurized
fluid, such as ~ir 4~ is provide~ which cc~mm~nica~es ~ith the
~on{luit 41 of the s~aling m~ndrel throu~h lin~ 51. ~n forming c)f
a head 53 s as illustrated in Fi&ure 3, the holLow tubular
element 1 with disc 17 in a moldable st~te9 i~i positloned within
the mold ca~i~y 2~ of mold ~o~m ~7~ und pressiure is applied~ as
indicute~ by the das~led arrow, to the sealing head 35 only ~o
form a seal o~ thermoplastic material, indica~ed at 55, be~ween
the first shoulder 39 on the sealing he~d and the eomplemen~ary
second shoul~er 47 o the mold ca~ity wall. After formation vf
~he seal of ~hermoplastic material 55$ air ~rom the source 49 is
lnjec$ed throug~ t~e con~ui~ 41 o~ the sealing mandrel 35 whic~
forees ~e por~ion o~ the thermoplastic disc ~urrounded by
sealed por~ion 55, while s~ill in a moldable state, into cont~ct
wlth the exposed wsll 31 of ~he mold ~or~, such ~Yi the threuded
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JIJN~ ;S7 TUE i5:35 ID: PMW I~ND K PGH TEL I`10: 412 2æl 1821 ~048 PlZ
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¦form illus~ra~ed~ to form the head of the t~be produced~ The
¦lnjection of ~he air agains~ the ~her~oplas~ic dis~ thus cause~
the por~ion ~ereof, whloh is not between the co~plementary
! flrst and seeond sealing shoul~ers 3~ and 47 to c~nform In shnpe
S ¦ ~o the predetermined shape, such as the cylindrical thread-llke
shape illustrated~ to form a closed end wall on the thermo-
¦ plastic ~ub~lar container o~ a predetermined shape.
Ano~her embodiment of the present method is illus-
l trated in Fl~ures 4 and 5, whereln a vacuum is applied to the
dlsc 7 while in ~ mold~ble æea~el rather than the fluld pres~re
~ppl~c~tlon embodlment of Fi~ures 2 and 3. A$ illusera~ed, a
sealing mandrel 57, sim:la~ to sealin~ mandrel 35 is provlde~,
except ~hat the conduit or ~xtension may be a ~olld rod-llke
elemen~ 59 h~ving a sealin~ head ~1 on the ~nd the~eof. The
seal~ ng head 61 has ~ firs~ ~houlder 63 ~hereon about ~he
s~rf~e ~hereof confron~ing the diec 17. The hollow ~bula~
element 1, with the di.s~ ~7 still in ~ m~ld~ble state, is
positloned ad~acent a ~old fo~m 65, whic~ may be ~n lntegral
unl~ or for~ed of mating sec~ions ~5a ~nd 65b, that has a cavl~y
2~ 67 therein wlth walls 6~ abou~ the cavlty, an~ one seetion 71 of
~he wall 69 ~a~ing a second shoul~er 73 ~hat is complemen~ary
with the first shou~er 63 on the sealin~ he~d 61 of the seall~g
mandrel S7. The~ nold form 65, in ~he area surroun~ed 4y the
second sho~lder 73 thereof, has a plurality of apertu~es 75
t~erein whlch extend from ~he wall ~9 of t~e cavity 67 to the
exterior ~ur~ace 77 of th~ mold ~orm 65. A source of vac~um 7
15 pro~ide~ which com~unic~te~ with t~e plurality o~ ~pe~tu~es
75 by means of line 8~ ~nd br~nch line5 83. In formin~ oi the
¦ head 53 usin~ v~u~m, AS illustrated ;n ~i~ur~ 5~ ~h~ hollow
ll -10-
~L285~64
tubular element 1 with moldable disc 17 is positioned within the
mold cavity 67, and pressure is applied, as indicated by the
dashed arrow, to the sealing head 61 only to form a seal of
thermoplastic material, indicated as 85, between the first
shoulder 63 on the sealing head and the complementary second
shoulder 73 of the mold cavity wall. After formation of the seal
of thermoplastic material 85, a vacuum is applied from source 7g
and through line 81, branch lines 83, and apertures 75, which
draws the portion of the moldable thermoplastic disc, surrounded
by sealed portion 85, into contact with the exposed wall 69 of
the mold form, such as the thread form illustrated, to form the
head of the tube produced. The application of the vacuum causes
the portion of the disc that is not between the complementary
first and second sealing shoulders 63 and 73 to conform in shap
to the predetermined shape, to form a closed end wall on the
thermoplastic tubular container.
In the embodiment of the present invention illustrated
in Figures 6 and 7, the application of fluid pressure, such as
air, in combination with the application of a vacuum, to form a
head are used. A hollow tubular element 1, with the disc 17
welded to the inner circumferential wall thereof, has an internal
sealing mandrel 35 inserted therein, the sealing mandrel having a
sealing head 37 on the end thereof. The sealing mandrel has a
first shoulder 39 about the surface confronting the disc, and
conduit 41 therein communicating with passageway 43 that extends
through the sealing head 3. A source of air 49 communicates
through line Sl with conduit 41.
The hollow tubular element on sealing mandrel 35 is
positioned adjacent a mold form 65 having a cavity 67, with
~2853G4
walls 69 about the cavity. The sealing head 37 has a first
shoulder 39 about the surface thereof confronting the disc, while
the wall 69 of cavity 67 in the mold form 65 has a second
shoulder 73 that is complementary with the said first shoulder
39. The area of mold form 65 surrounded by second shoulder 73
has a plurality of aper-tures 75 therein, extending from wall 69
to the exterior surface 77 thereof, and a source of vacuum 79
communicates with said apertures 75 through line 81 and branch
lines 83.
Figure 7 illustrates formation of a threaded head using
both fluid pressure and vacuum. The hollow tubular element 1,
with disc 17 still in a moldable state, is positioned in mold
cavity 67, and pressure applied, as indicated by the dashed
arrow, to the sealing line 37 only to form a seal 87 of
thermoplastic material between first shoulder 39 on the sealing
head 37 and the complementary second shoulder 73 in the mold form
65. After the seal 87 is formed, vacuum ls applied through line
81, branch lines 83, and apertures 73 to the surface 89 of the
disc faciny the mold cavity wall 69, while at the same time, air
from source 49 is in~ected through the conduit 41 of the sealing
mandrel 35 against the surface 91 of the disc facing the sealing
head 37. Application o~ both vacuum to one side of the disc
surrounded by shoulder 73 and fluid pressure to the other side of
the disc surrounded by shoulder 39 forces that exposed area of
the disc to conform to the shape, such as the threaded head shape
illustrated.
As aforedescribed, the application of a fluid pressure,
application of a vacuum, or both are made while the
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JUN~ æ7 TUE 15:37 ICI: PMW fll`ll:` K PGH TEL NO: 41~! 2~31 1821 #04æ P15
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¦thermop~ ic dl6c is stilL in a moldable sta~e. The the~mo-
¦plastic m~teri~l of the dl~c is no longer In a p~rely molten
staee or above lts melting point after the l~ten~ heak ~hereof
l has welded the disc to the tubular ele~ent wall, but ~ust s~ill
¦ be above the ~lass ~ransition ~emperature of ths thermoplastic
¦ so tha~ the disç is soft an~ flexible ~nd moldable to the
deslred shape.
When ~he applicatlon of pressure is used ~o for~ the
l head, pressures between abou~ 5 to 140 pounds pe~ squ~re lnch
l are used. When a vac~um is applied to fo~m the head, a ~cuum o
about 10 to 30 i~c~e~ are used. The ~hermoplastio tub~lar
l container formed according ~o the present method will norm~lly
: ¦ have a ~bula~ wall section of between ~hout 0.010 to 0.040 inch
:: in wall thickness, while the head port~on ormed thereon w~llhs~e a thickne~s of abou~ 0.010 tG 0.080 inch in wall thickness.
The presen~ method is also usable to for~ thermo-
plastic contalners of lamina~ed or layer~d thermoplastic
maeerials. SLIC~ la~inates comprise layers o~ ~ the~moplastic
m~terlal an~ a barrier layer suc~ as aluminum ~oil, o~ ~he llke,
or lay~rs vf varient plastlc ~a~eria~s w~ieh may be ~o-ex~ruded
in layers to form a multi-layer thermopLastlc materl~l. In
formatlon of such lamin~ted tubula~ therm~plasti~ containers,
the tubular wall section and plast~ dlsc are formed fro~
laminated plastic materlal and then sealed to~ether an~ molded
as woul~ be a thermoplasti~ ~ub~lar ~ontainer of a single
thermoplas~lc material. Such a l~minate oi~ three layers, in the
disc and hollow ~ubular el~ment ~ would, for example have Inner
~nd o~er l~yers of a materi~l such as polyethylene, or other
thermoplastic; while An lnterme~i~te l~yer) such a~ an oxy~en
.
JUl`i-16 i'~'7 TUE 15:~ ID: PMW hl~lD K PGH TEL N0: 412 ~ 21 #04~ P16
2 ~ ~ 3 ~ ~
l-npermeable layer, would be o~ a polyamide su~ as nylon, or
ethylene polyvl~yl ~lcohol, or the llke- Or, a flve l~yer
~mpol~c c~uld be us~ ha~in~ successive layers of an outer
l thermopl~stlc resin, a~hesl~e, ln~erme~iate impermeable laye~,
¦ adhesive, and an inner ther~oplastic ~esin. The ~hermoplastlc
resin ~an colnprise polyeth~lene, polypropylene, a polyester such
AS polyetllylene t~rephthalate, or ~he like, while the i~er-
medlate i~permeable layer can ~omprise an oxygen i~permeable
l materinl such as nylon, ethylene poly~inyl alcohol, polyvinyl-
l idene chlori~e, or the like, wi~h the tw~ adheslv~ laycrs
supplied c~ bon~ the intermediate layer ~o each of ~he inne~ and
l outer layers.
¦ The productlon of ~arious embodimen~s of ~omplex heada
l that may be formed accordin~ to the present ~e~thod~ and not
lS l readily by the original Down's process, ls illustrated in
Fi~res 8 through 16.
Fi~ure6 8 ~hrough 10 ill~str~te for~ation of a
bulb-like head on a hollow ~bular eleme~ Figure 8 ~llus~ates
a hollow tu~ular element 1, with A welded di~ 17 secured
~here~o~ and Wi~ the sealing mandrel removed, positioned
adjacen~ a mold form 27, ~ormed of m~table mold form sec~lon~
~7~ and 27b. ~he mold cavi~y ~9 ;s in ~he for~ o~ a spherlcal
ravity. Fi~uPe 9 ill~strates the application of ~luid pressure
from the sealing mandrel 35, through conduit 41 t~at communa-
cates with passa~eway 43 in the sealing head 37, to form the
disc, while in a moldable ~ta~e~ into eonformity with the walls
31 of the mold cav~ ty 2g, ~o form a bulbous head 93 on the end
of tl-e hollow tubular e~ement ae illustrated ln ~i~ure 10. Such
a ~ulbous head would no~ readily ~ formed uslng a formlng
353~
mandrel since the same would not be able ko pass the constrictive
portion 95 between the tubular element 1 and the bulbous head 93.
Figures 11 and 12 illustrate formation of another
complex head embodiment according to the present method that is
in the form of an applicator head for application of ointments or
the like, over a larger area than would be provided by a single
tube outlet. The applicator head 97 has a plurality of
protrusions 99 through which orifices would be formed such that
the contents of the finished and packed tube would be ex~dable
through the plurality of apertures over a large surface area.
Figures 13 and 14 illustrate formation of a novelty
type head 101, in the shape of a clown's head, with a constricted
portion 103 forming a neck for the clown and wlth a cap 105,
later applied, covering the orifice (not shown) for dispersing
the product being in the form of a hat for the clown.
Figures 15 and 16 illustrate formation of a twist-off
or ampoule-like head 107 for a hollow tubular element, where a
very narrow constriction 109 is provided between the body of the
tubular contour 111 and a gripable head portlon 113. By grasping
the gripable head portion 113 and twisting the same, a break at
constrictive portion 109 would occur, with access to the contents
of the body 111 of the tubular contalner effected.
It should be noted that in Figures 8 through 16, the
application of fluid pressure is illustrated, while equally
effective would be the application of vacuum through a mold form,
as previously described, as well as application of both fluid
pressure and vacuum, as also previously described herein in
accordance with the present method.
- 15 -
JUI`I-16-'13~ TUE 15~ P;1W f~ilD K PGH TEL l~m: 4i2 Zæ1 1æ21 ~ 48 P18
I f~
~3~ii3~L
The pr~sent rnethod enable~ ~he produc~ion of complex
head desi~ns ~hat arç not: readily prod~ced usin~ compreæsion
moldln~ iAS ef~ecte~l Ln the prior art, wlll enable ~he use of a
l ~:hinner disc in the format~on of he~.~s on tubul~r elem~nts, and
s ¦ provides an efflci~nt and ~aonc~mical meAni for formlng he~ds vn
thermoplastic ~ubes.
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