Note: Descriptions are shown in the official language in which they were submitted.
~55~Z~L3 12560
This lnvention relates to a plastic eo~tainer
having a reclosable fastener.
Generally, plastic containers which feature
reclosable fasteners are well known and are widely used
by consumers and industry. This popular use has provided
a strong impetus for the development of improved manufac-
turin~ equipment and methods for economical operations as
well as products which have appeal in the mar~etplace.
One prior ar~ method is described in the U.S.
Patent No. 3,846,209 to Howard. The method of joining
multiple stock components together as disclosed in this
: patent can result in frequent stock changes and thereby
reduce m~anufacturing efficiency.
Another prior art method is described by U.S.
- Reissue Patent Re. 29208 to Naito. This patent disclosed
a blown film die which defines both a tubular film and
`; ;- closure elements for the fastener. Such integral extru-
sion appears to have potential advantages, but it is
pointed out in U.S. Patent No. 3,848,035 to Behr that
- the integral extrusion is extremely difficul~ ~o carry
; out. The U.S~ Patent No. 3,338,284 to Ausnit also dis-
closes an integrally extruded sheet and fastener for a
container but does not consider any method or equipment
for producing the article~
The U.S. Patent No. 3,904,468 to Noguchi dis-
closes a method in which closure strips for a fastener
are freshly extruded onto a heated film and pressed into
the film with nip rolls. The U.S. Patent No. 3,462,332
to Goto discloses slot casting film onto a ehill roll
and extruding the closure strips of the fastener onto
2.
the ho~ film ~o connect them to the film. The ~.S.
Paten~ No. 4,101,355 to Ausnit discloses ronnecting
together prefabricated film and a prefa~ ated fastener
and the U.S. Patent No. 3,582,571 to Ausnit discloses
connecting a prefabricated preheated fastener ~o a
freshly ex~ruded iilm.
All of these patents present problems in manu-
facturing, such as twisting of the closure strips, or
positioning of the closure strips, or rate of operation
without distortions, or other problems which reducP speed
and increase costs.
, .
- -The instant invention overcomes these problems
~ by the implementation of a surprising method and appara-
: : ~ tus.
` ;~. A first principa:L embodiment of the invention
is an apparatus for produc:ing a pl~stic film connected
. , ,
o a pair of occludable closure serips, each having pro-
file and base portions; comprising feeding means for
supplying the closure strips; a rotatable casting cylindPr
having a pair of spaced apart circumferential grooves de-
fined therein; advancing means for advancing the closure
strips to the casting cylinder so that the respective
profile portions extend into the respective grooves; ex-
truding means for casting a plastic film onto the casting
cylinder so that the plastic film becomes connec~ed to
the base portions; urging means for pressing the plastic
film against the base portions; and cooling means for
receiving the combination of the plastic film and closure
strips to provide cooling.
Another embodiment of the invention features
12560
5~ Z~1 3
heating means for preheating the closure strips prior
to the closure strips contacting the casting cylinder.
Ano~her embodiment of the invention features
the cooling means comprising a chill roll.
A further embodiment of the invention features
the urging means comprising a cnill roll.
.. . Yet another embodiment of the invention fea-
tures the urging means comprising an air knife. An air knif~
is a known device in the form of an air blower having a
slotted nozzle for directing an airstream produced by
tke blower.
A second principal embodiment of the invention
is a metho~ for producing a plastic film connected to a
pair of occludable closure strips, each having profile
and base portions; comprising the steps of supplying the
closure strips; ad~ancing the closure strips to a rotat-
able cas~ing cylinder having a-pair of spaced apart cir-
cumferential grooves so that the respectiv~ profile
portions extend into the respective grooves; extruding
a plastic film onto the casting cylinder so that it be-
comes connected to the base portions; and thereafter
cooling the combination of the plastic film and closure
s~rips.
Another embodiment of the invention as set
forth in the second principal embodiment features the
step of preheating the closure s~rips beore the closure
strips are advanced to the casting cylinder.
Another embodiment is the further step of eli-
minating air entrapment between the plastic film and the
- 30 closure s~rips.
Further advantages of the invention will be
set forth in part in the following and in part will be
obvious therefrom without being specifically referred
to, the same being realized and attained as pointed out
in the claims hereof. :
For a fuller understanding of the nature and
objects of the invention, reference should be had to the
following detailed description, taken in connection with
the accompanying drawings, in which:
Fig. 1 is a diagrammatic elevational view of
one embodiment of the invention;
Fig. 2 is a sectional view along the line 2-2
of the casting cylinder of Fig. l;
Fig. 3 is another embodiment of a portion of
the invention of Fig. l; and
Fig. 4 is a further embodiment of a portion of
the invention of Fig. 1.
In carrying the invention into effect, several
embodiments ha~e been selected for illustration in the
accompanying drawings and for description in this speci-
fication, reference being had to the Figures.
In Fig. 1, occludable closure strips 6 and 7
which define a fastener 8 are supplied from a supply
source 9. The source 9 can be a roll of prefabricated
closure strips or an in-line operation which supplies
closure strips.
Reference is had to U. S. Patent 4,212,337 having
the same applicant and assignee as the instant application.
5.
,
~$~13
U S. Patent 4,212,337 discloses a preferred fastener
for the instant invention because the closure strips
are u-shaped channels.
A control roll 11 feeds the closure strips 6
and 7 to an optional heating means 12 for preheating the
base portions of the closure strips 6 and 7. The heating
means 12 can be a rotating heated roll as shown or a hot
air blower or the like. The closure strips 6 and 7 then
move to a rotating casting cylinder 13 which has a pair
of spaced apart circumferential grooves as can be seen
from Fig. 2. The temperature of the casting cylinder 13
depends on the resins used for the process. It is impor-
tant to avoid raising the temperature of the profile
portions to a level at which distortions can occur. The
temperature of the casting cylinders must be sufficlent
to achieve a good adhesion between the closure strips 6
and 7 and the plastic film 14.
The plastic film 14 is slot extruded from ex-
truding means 16 onto the casting cylinder 13 to become
connected to the closure strips 6 and 7.
Urging means such as roll 17 provides cooling
and lay-flat control and presses the plastic film 14
against the base portions of the closure strips 6 and 7.
A cooling means such as, chill roll 18 provides cooling
before the combination of the plastic film 14 and the
closure strips 6 and 7 is advanced for further operations
to produce a plastic container.
The roll 17 can be replaced or supplemented hy
an air knife 19 as shown in Fig. 3.
6.
'
~3
Fig. 4 shows a portion of the embodiment of
Fig. 1 with a suc~ion device 21 near the casting roll
13 and the extruding means 16. The suction device 21
is positioned to draw air away from the point that the
closure strips 6 and 7 contact the plastic film 14 in
order to minimize air entrapment. This improves the
bond between the closure strips 6 and 7 and the plastic
film 14.
I wish it to be understood that I do not
desire to be limited to the exact details for obvious
modifications will occur to a person skilled in the art.
; ~:
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