U.S. patent application number 14/979838 was filed with the patent office on 2016-04-21 for techniques to mold parts with injection-formed aperture in gate area.
The applicant listed for this patent is Kortec, Inc.. Invention is credited to Paul M. Swenson.
Application Number | 20160107350 14/979838 |
Document ID | / |
Family ID | 51528318 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160107350 |
Kind Code |
A1 |
Swenson; Paul M. |
April 21, 2016 |
TECHNIQUES TO MOLD PARTS WITH INJECTION-FORMED APERTURE IN GATE
AREA
Abstract
Methods and systems for co-extruding multiple polymeric material
flow streams into a mold cavity to produce a molded plastic article
having an injection-formed aperture in gate region of the article
are disclosed herein. A method includes providing a valve pin
having a distal portion with a first diameter and a mid-portion
with a second diameter smaller than the first diameter and
providing a mold defining a cavity corresponding to a shape of a
resulting molded plastic article. The mold has a recess aligned
with a gate region of the mold, extending into the mold and
configured to receive the distal portion of the valve pin when the
distal portion of the valve pin extends beyond the gate region. The
method includes advancing the distal portion of the valve pin into
the recess until the mid-portion of the valve pin at least
partially extends into the gate region, thereby establishing a flow
path for a combined polymeric stream into the cavity at the gate
region for forming a molded plastic article having at least one
layer of a first polymeric material and at least one layer of a
second polymeric material. The method also includes withdrawing the
mid-portion of the valve pin from the gate region, thereby forming
an injection-molded aperture in the resulting molded plastic
article at the gate region.
Inventors: |
Swenson; Paul M.; (South
Hamilton, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kortec, Inc. |
Rowley |
MA |
US |
|
|
Family ID: |
51528318 |
Appl. No.: |
14/979838 |
Filed: |
December 28, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13827293 |
Mar 14, 2013 |
9221204 |
|
|
14979838 |
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Current U.S.
Class: |
428/35.7 ;
264/241 |
Current CPC
Class: |
B65D 85/8043 20130101;
B32B 2250/03 20130101; Y10T 428/139 20150115; Y10T 428/1393
20150115; B32B 2439/70 20130101; Y10T 428/1383 20150115; Y10T
428/1379 20150115; B29L 2031/712 20130101; B32B 27/08 20130101;
B32B 2307/74 20130101; B32B 2323/10 20130101; B32B 2323/04
20130101; Y10T 428/13 20150115; B32B 2329/00 20130101; B32B 1/02
20130101; B32B 3/28 20130101; B32B 2307/7248 20130101; B32B
2250/246 20130101; B65D 35/08 20130101; B32B 2250/40 20130101; B29C
45/231 20130101; B32B 27/365 20130101; B32B 2250/02 20130101; B32B
2250/44 20130101; B32B 27/36 20130101; B32B 27/306 20130101; B32B
2250/24 20130101; B32B 2307/7244 20130101; Y10T 428/24322 20150115;
B29C 45/1603 20130101; B32B 3/30 20130101; B29C 2045/2882 20130101;
B29C 2045/2862 20130101; B32B 1/08 20130101; B32B 3/02 20130101;
B32B 3/266 20130101; B29C 45/7613 20130101; B32B 2307/7246
20130101; B32B 2439/00 20130101; B29L 2009/00 20130101; B32B 27/32
20130101; B32B 27/34 20130101; B29C 45/2896 20130101; B32B 1/04
20130101 |
International
Class: |
B29C 45/16 20060101
B29C045/16; B32B 3/26 20060101 B32B003/26; B32B 1/02 20060101
B32B001/02; B29C 45/23 20060101 B29C045/23; B29C 45/28 20060101
B29C045/28 |
Claims
1. A co-injection-molded plastic article comprising: a sidewall
portion including: outer layer comprising a first polymeric
material; an inner layer comprising the first polymeric material;
and an interior layer disposed between the outer layer and the
inner layer; an aperture formed by co-injection molding at a gate
region of the article; and a shoulder portion disposed between the
sidewall portion and the gate region, wherein the interior layer of
the sidewall portion extends into the shoulder portion.
2. A co-injection-molded plastic article comprising: a sidewall
portion including: outer layer comprising a first polymeric
material; an inner layer comprising the first polymeric material;
and an interior layer disposed between the outer layer and the
inner layer; an aperture formed by co-injection molding at a gate
region of the article; a first sealing surface; and a second
sealing surface; wherein the interior layer extends through a
portion of the article between the first sealing surface and the
second sealing surface.
3. A non-transitory computer-readable medium storing computer
executable instructions for producing a co-injection-molded plastic
article using a system including a valve pin having a distal
portion with a first diameter and a mid-portion with a second
diameter smaller than the first diameter, a mold defining a cavity
corresponding to a shape of the resulting molded plastic article,
the mold having a recess aligned with a gate region of the mold,
extending into the mold and configured to receive the distal
portion of the valve pin when the distal portion of the valve pin
extends beyond the gate region, and an injection nozzle, the
instructions including instructions for: forming a combined
polymeric stream in the injection nozzle, the combined polymeric
stream comprising a first polymeric material and a second polymeric
material; advancing the distal portion of the valve pin into the
recess until the mid-portion of the valve pin at least partially
extends into the gate region of the mold, thereby establishing a
flow for the combined polymeric stream into the cavity at the gate
region for forming a molded plastic article having at least one
layer of the first polymeric material and at least one layer of the
second polymeric material; and withdrawing the mid-portion of the
valve pin from the gate region, thereby forming an aperture in the
molded plastic article at the gate region.
4. The computer-readable medium of claim 3, wherein the
instructions further include instructions for heating the
mid-portion of the valve pin.
5. The computer-readable medium of claim 3, wherein an outer stream
of the first polymeric material encases an interior stream of the
second polymeric material in the combined polymeric stream.
6. The computer-readable medium of claim 3, wherein the cavity
defines a sidewall portion and wherein the flow of combined
polymeric flow stream into the sidewall portion forms an inner
layer of the first polymeric material, an outer layer of the first
polymeric material, and an interior layer of the second polymeric
material between the inner layer and the outer layer.
7. The computer-readable medium of claim 6, wherein the interior
layer is a barrier layer or a scavenger layer.
8. The computer-readable medium of claim 6, wherein the interior
layer terminates proximate to the aperture.
9. The computer-readable medium of claim 6, wherein the article has
a sealable portion and wherein the interior layer terminates
proximate to the sealable portion.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation under 35 U.S.C.
.sctn.120 of U.S. patent application Ser. No. 13/827,293, filed
Mar. 14, 2013, the entire contents of which is incorporated herein
by reference.
FIELD
[0002] Example embodiments are directed to methods and systems for
forming multi-layer plastic articles, such as containers used to
hold food, beverages, pharmaceuticals and nutraceuticals. In
particular, example embodiments relate to methods and systems for
co-injection molding multi-layer plastic articles that include an
aperture formed in a gate region of the container.
BACKGROUND
[0003] Multi-layer plastic articles are often used as containers to
hold, food, beverages, pharmaceuticals, and nutraceuticals. Some
multi-layer plastic articles are commonly made from materials such
as polyethylene (PET) and polypropylene (PP). Articles made from
PET and PP resist environmental degradation, and are reasonably
durable, watertight, and economically produced. However, plastic
materials such as PET and PP are gas (e.g., oxygen, nitrogen, etc.)
permeable. For applications in which gas permeability is
undesirable, for example, containers for food products, medicines
and products that degrade upon gas permeation into or out of the
container, a plastic article of PET or PP may include an interior
layer of a barrier material or a gas scavenger material, such as
ethylene vinyl alcohol (EVOH), between skin layers of PET or
PP.
[0004] Molded plastic articles, such as containers for food,
beverages, pharmaceuticals, nutraceuticals, etc., often have an
open end used to fill the container with product. Some plastic
containers also have an aperture, away from the open end. For
example, some cartridges for single serve coffee machines have a
multi-layer plastic body including an open top portion through
which the container is filled with ground coffee and a smaller
aperture in a bottom portion through which brewed coffee is
dispensed. Such plastic bodies for single serve coffee machines are
commonly made by first thermoforming the plastic body with a wide
top portion, aligning the thermoformed article with a mechanical
punch, and mechanically punching out the smaller aperture in a
bottom portion. The additional separate cutting or punching step
increases the complexity of the production process. Further, in
applications where the accuracy or precision of the position of the
aperture, or of the diameter of the aperture is important,
sufficient accuracy or precision may be difficult to achieve with a
punch process or a cutting process.
[0005] Other plastic containers including an open end portion and
an aperture formed in a different portion of the container may
commonly be formed or molded in separate pieces that are then
joined together. For example, a plastic container for tooth paste
(e.g., a tooth paste tube), may have a thin-walled tail end portion
that is initially open to be filled with tooth paste before being
sealed, and a thick-walled head end portion with a small aperture
for dispensing the tooth paste. Such a container is commonly made
by forming the thin-walled tail end portion, separately forming the
thick-walled head end portion, and then joining the two pieces
together.
SUMMARY
[0006] Example embodiments described herein include, but are not
limited to, a method of co-extruding a plurality of polymeric
material streams to produce a molded plastic article with a molded
aperture in a gate region, a system for co-extruding a plurality of
polymeric material streams to produce a molded plastic article with
a molded aperture in a gate region, and a co-injection molded
multilayer article having a molded aperture in a gate region.
[0007] An embodiment includes a method of co-extruding a plurality
of polymeric material streams to produce a molded plastic article.
The method includes providing a valve pin having a distal portion
with a first diameter and a mid-portion with a second diameter
smaller than the first diameter. The method also includes providing
a mold defining a cavity corresponding to a shape of a resulting
molded plastic article. The mold has a recess aligned with a gate
region of the mold, that extends into the mold and is configured to
receive the distal portion of the valve pin when the distal portion
of the valve pin extends beyond the gate region. The method further
includes forming a combined polymeric stream in an injection
nozzle, the combined polymeric stream including a first polymeric
material and a second polymeric material. The method also includes
advancing the distal portion of the valve pin into the recess until
the mid-portion of the valve pin at least partially extends into
the gate region, thereby establishing a flow path for the combined
polymeric stream into the cavity at the gate region. The flow of
the combined polymeric stream into the cavity at the gate region
forms a molded plastic article having at least one layer of the
first polymeric material and at least one layer of the second
polymeric material. The method also includes withdrawing the
mid-portion of the valve pin from the gate region, thereby forming
an injection-molded aperture in the resulting molded plastic
article at the gate region.
[0008] In some embodiments, the aperture coincides with the distal
portion of the valve pin. In some embodiments, an outer stream of
the first polymeric material encases an interior stream of the
second polymeric material in the combined polymeric stream.
[0009] In some embodiments, the cavity includes a sidewall portion
and the flow of combined polymeric flow stream into the sidewall
portion forms an inner layer of the first polymeric material, an
outer layer of the first polymeric material, and an interior layer
of the second polymeric material between the inner layer and the
outer layer. In some embodiments, the interior layer may be a
barrier layer or a scavenger layer. The interior layer may extend
from the sidewall portion into the shoulder portion. The interior
layer may terminate in the shoulder portion in some embodiments.
The interior layer may terminate proximate to the aperture. In some
embodiments, the article has a sealable portion and the interior
layer terminates proximate to the sealable portion. In some
embodiments, the article has a sealing surface and the interior
layer terminates proximate to the sealing surface.
[0010] An embodiment includes a system for co-extruding a plurality
of polymeric material streams to form at least one molded plastic
article having multiple plastic layers and an injection-formed
aperture proximal to a gate region of the molded plastic article.
The system includes a first material source to supply a first
polymeric material for use in forming at least one layer of a
molded plastic article and a second material source to supply a
second polymeric material for use in forming at least one layer of
the molded plastic article. The system also includes an injection
nozzle including a valve pin having a distal portion with a first
diameter and a mid-portion with a second diameter smaller than the
first diameter. The system includes a mold defining a cavity
corresponding to a shape of a resulting molded plastic article, the
mold including a recess aligned with the valve pin and proximal to
the nozzle. The recess of the mold is configured to receive the
distal portion of the valve pin when the valve pin is advanced into
the recess until the mid-portion of the valve pin at least
partially extends into the gate region. The injection nozzle has an
egress part capable of communicating with the cavity to inject a
combined polymeric stream including the first polymeric material
and the second polymeric material into the cavity. The system also
includes a first flow channel configured to distribute the first
polymeric material from the first material source to the nozzle and
a second flow channel configured to distribute the second polymeric
material from the second material source to the nozzle.
[0011] In some embodiments, the nozzle is configured to form the
combined polymeric stream including an inner stream and an outer
stream of the first polymeric material encasing an interior stream
of the second polymeric material. In some embodiments, the nozzle
is configured to heat a mid-portion of the valve pin.
[0012] An embodiment includes a non-transitory computer-readable
medium storing computer-executable instructions for producing a
co-injection-molded plastic article using systems and/or methods
described herein.
[0013] An embodiment includes a co-injection-molded plastic article
with a sidewall portion having an outer layer and an inner layer
including a first polymeric material, and an interior layer
including a second polymeric material disposed between the outer
layer and the inner layer. The article also includes an aperture
formed by co-injection molding at a gate region of the article and
a shoulder portion disposed between the sidewall portion and the
gate region with the interior layer of the sidewall portion
extending into the shoulder portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The drawings are intended to illustrate the teachings taught
herein and are not intended to show relative sizes and dimensions,
or to limit the scope of examples or embodiments. In the drawings,
the same numbers are used throughout the drawings to reference like
features and components of like function.
[0015] FIG. 1 is schematic cross-sectional view of a co-injection
molding system for producing one or more multi-layer molded plastic
articles, each having a molded aperture formed in a gate region of
the article, in accordance with various embodiments.
[0016] FIG. 2 schematically depicts a cross section-view of the
nozzle and of one of the mold cavities of FIG. 1.
[0017] FIG. 3 is a flow chart schematically depicting a method of
co-extruding a plurality of polymeric plastic material streams to
produce a multi-layer molded plastic article having a molded
aperture in a gate region of the article, in accordance with
various embodiments.
[0018] FIG. 4 is a detail view of the nozzle and the mold cavity of
FIG. 2 showing a distal portion of a valve pin extending into a
recess of the mold.
[0019] FIG. 5 is a detail view showing a mid-portion of a valve pin
extending into a gate region of the cavity and a combined polymeric
plastic stream entering the cavity.
[0020] FIG. 6 is detail view after the cavity is substantially
filled with the injected co-polymer stream.
[0021] FIG. 7 is a detail view as a distal portion of the valve pin
is being withdrawn from the cavity forming a molded aperture at the
gate region.
[0022] FIG. 8 schematically illustrates a cross-sectional view of
the resulting co-injection-molded plastic article having a molded
aperture at the gate region of the article.
[0023] FIG. 9 schematically illustrates a cross-sectional view of
the co-injection-molded plastic article of FIG. 8 in use as a
container, in accordance with some embodiments.
[0024] FIG. 10 schematically illustrates a cross-sectional detail
view of a variation of the container of FIG. 9 having an external
seal at a first end portion of the container, in accordance with
some embodiments.
[0025] FIG. 11 schematically illustrates a cross-sectional view of
another co-injection-molded plastic article in use as a container,
in accordance with some embodiments.
[0026] FIG. 12 schematically illustrates a cross-sectional detail
view of a variation of the container of FIG. 11 having a barrier
layer that terminates in a shoulder portion of the container, in
accordance with some embodiments.
[0027] FIG. 13 schematically depicts an exemplary nozzle assembly
suitable for practicing embodiments taught herein.
[0028] FIG. 14 schematically illustrates an exemplary computing
environment suitable for practicing exemplary embodiments taught
herein.
DETAILED DESCRIPTION
[0029] Example embodiments include methods and systems for
co-extruding a plurality of polymeric material streams to produce a
molded plastic article having multiple layers and a molded aperture
formed in a gate region of the article. Such methods simplify a
production process by producing the plastic article and the formed
aperture in the same injection-molding process, in comparison with
processes in which an aperture is punched out after an article is
formed, and in comparison with processes in which different
portions of the article are formed separately and then joined
together.
[0030] Exemplary systems and methods employ an injection nozzle
with a valve pin having a distal portion with a larger diameter
than that of a mid-portion of the valve pin. Exemplary systems and
methods also employ a mold having a cavity and a recess aligned
with a gate region of the cavity, extending into the mold and
configured to receive the distal portion of the valve pin. In use,
the distal portion of the valve pin is advanced into the recess and
the mid-portion of the valve pin extends at least partially into
the gate region of the cavity thereby establishing a flow path for
the combined polymeric stream into the cavity for forming a molded
plastic article. After the cavity is filled or substantially
filled, the valve pin is withdrawn from the recess and cavity. More
specifically, the mid-portion of the valve pin is withdrawn from
the gate region, thereby stopping the flow of the combined
polymeric flow stream into the cavity, and the distal portion of
the valve pin is withdrawn from the recess through the gate region
of the cavity, thereby forming a molded aperture in a region of a
resulting molded plastic article corresponding to the gate region
of the cavity.
[0031] FIG. 1 illustrates a system 1000 suitable for practicing
exemplary embodiments. Co-injection molding system 1000 is
configured to co-inject at least two polymeric plastic material
streams into a mold cavity to produce one or more articles each
having multiple co-injected plastic layers and a molded aperture in
a gate region of the article. Co-injection molding system 1000
includes a first material source 1200, a second material source
1400. First material source 1200 supplies a first polymeric
material for use in forming at least one layer of a resulting
molded plastic article. Second material source 1400 supplies a
second polymeric material for use in forming at least one layer of
the resulting molded plastic article. System 1000 co-injects
multiple streams (e.g., an inner stream, an outer stream, and an
interior stream) to form multiple layers of a resulting article.
Materials suitable for use with embodiments of the invention
include, but are not limited to, polymer-based materials such as,
polyethylene terephthalate (PET), ethylene vinyl alcohol (EVOH),
MXD6 nylon, polypropylene (PP), and polycarbonates (PC). In many
embodiments, the inner and outer streams are the same polymeric
material. For example, in some embodiments, the inner and outer
streams which form inner and outer layers are PET, while an
interior stream used to form an interior layer is a material chosen
to enhance the overall performance of the resulting article, or to
reduce the cost of the resulting article. For example, one or more
interior streams for interior layers may include one or more of a
barrier material (MXD6 Nylon or EVOH), an oxygen scavenging
material, a recycled material, or other performance-enhancing or
cost-reducing material. The type of material used for the interior
layer/stream is often different from the type of material used for
the inner and outer layers/streams.
[0032] System 1000 may also include a manifold 1600 for delivery of
polymeric material. In some embodiments, a manifold may consist of
separate manifolds for each polymeric material. Co-injection
molding system 1000 further includes nozzle assemblies 18A, 18B,
18C, 18D and mold 2400. Mold 2400 defines gates 20A, 20B, 20C, 20D,
cavities 22A, 22B, 22C, 22D, and recesses 23A, 23B, 23C, 23D. In
FIG. 1, each nozzle assembly (18A, 18B, 18C, and 18D) has a
corresponding gate, cavity, and recess. For example, nozzle
assembly 18A corresponds to gate 20A, cavity 22A, and recess 23A.
Further details regarding the recesses 23A-23D are provided below
with respect to FIGS. 2, and 4-8.
[0033] A first polymeric material is extruded from first material
source 1200 and a second polymeric material is extruded from second
material source 1400. System 1000 includes a first flow channel
1610 of manifold 1600 configured to distribute the first polymeric
material to one or more of nozzles 18A-18D, and a second flow
channel 1620 of manifold 1600 configured to distribute the second
polymeric material to one or more of nozzles 18A-18D. First
polymeric material and second polymeric material combine into a
co-polymeric stream in nozzles 18A-18D, which is injected into mold
cavities 22A, 22B, 22C, 22D for molding resulting articles. In
nozzles 18A-18D, the first and second polymeric streams are
combined to form an annular combined polymeric stream such that the
second polymeric material forms an interior core stream in the
combined polymeric stream while the first polymeric material forms
the inner and outer streams in the combined stream. The inner and
outer streams encase the interior core stream as the annular
combined polymeric stream is injected from the nozzle. Methods for
co-injecting multiple polymeric materials to form plastic articles
with multiple layers of different materials are generally known,
such as described in U.S. Pat. No. 6,908,581 and the documents
incorporated therein, each of which is also incorporated by
reference herein in its entirety. Further details regarding how a
combined polymeric plastic stream is produced in the injection
nozzle are provided in the description of FIG. 12 below.
[0034] Although system 1000 is depicted including four nozzle
assemblies and a mold that defines four gates (20A-20D), four
cavities (22A-22D), and four recesses (23A-23D) for forming four
plastic articles simultaneously, one of ordinary skill in the art
will appreciate that other embodiments may include different
numbers of nozzle assemblies, gates, cavities and recesses for
forming different numbers of plastic articles simultaneously. For
example, embodiments may include one, two, three, four, or more
than four sets of nozzle assemblies, gates, cavities and recesses.
Example embodiments for large scale production systems may include
more sets of nozzle assemblies, gates, cavities and recesses (e.g.,
64 or more sets).
[0035] FIG. 2 schematically illustrates a nozzle 18, which may be
referred to as a nozzle assembly, and the mold 2400 that defines at
least one cavity 22 corresponding to a shape of a resulting plastic
article. Mold 2400 also defines a corresponding gate 20, through
which a combined polymeric plastic stream 70 produced by nozzle 18
flows into cavity 22. A region of cavity 22 proximal to gate 20 is
referred to as a gate region 21 of the cavity.
[0036] Nozzle assembly 18 includes a nozzle body 36, a nozzle tip
38, and a valve pin 42. Nozzle tip 38 includes an output portion 39
(also referred to as an egress part of the nozzle) capable of
communicating with cavity 22 to inject combined polymeric plastic
stream 70 into cavity 22. In some embodiments, the nozzle tip 38
may be separated from the gate 20 of the mold 2400 by a gap 29
(e.g., a 1.5 mm separation between the output portion 39 of the
cavity and the gate 20 of the mold). After the first molding cycle,
much of the gap 29 is filled with polymer material (e.g., a skin
material) as shown. The gap 29 filled with polymer insulates the
nozzle tip 38 from the first mold portion 2400a, thereby reducing
the conduction of heat from the relatively hot nozzle tip 38 to the
relatively cold first mold portion 2400a. However, the nozzle body
36 and the first mold portion 2400a may form a metal to metal seal
28 (e.g., that contains the polymer material in the gap 29).
[0037] Valve pin 42 controls flow of combined polymeric plastic
stream 70 from output portion 39 into cavity 20 through gate 20.
Valve pin 42 includes a distal portion 42a having a first diameter
D.sub.1, a mid-portion 42b having a second diameter D.sub.2 smaller
than the first diameter, and a proximal portion 42c having a third
diameter D.sub.3 (see also FIG. 4). In FIG. 2, distal portion 42a
of the valve pin is shown blocking a flow of combined polymer
stream 70 from nozzle assembly 18 into gate 20.
[0038] Mold 2400 also includes a recess 23 that is aligned with
gate 20. Recess 23 is configured to receive distal portion 42a when
valve pin 42 is advanced into mold 2400 such that mid-portion 42a
extends at least partially into gate region 21, (see FIGS.
5-7).
[0039] As shown, mold 2400 may include a first mold portion 2400a
and a second mold portion 2400b. A co-injection molded article
produced by system 1000 may be released from mold 2400 by
separating second mold portion 2400b from first mold portion 2400b.
Recess 23 extends into the second mold portion 2400b. In some
embodiments, recess 23 may extend through or substantially through
second mold portion 2400b. In other embodiments, a recess may
extend only partially through second mold portion 2400b. In some
embodiments, cavity 22 may have a shoulder portion 24 for molding a
shoulder portion of the resulting article, a sidewall portion 25
for molding a sidewall portion of the resulting article, and a
distal portion 26 for forming a distal portion of the resulting
article.
[0040] The flow chart in FIG. 3 schematically depicts a method 300
of co-extruding a plurality of polymeric material streams to
produce a molded plastic article having an aperture formed in a
gate region of the article. For illustrative purposes, the method
is described with reference to exemplary system 1000; however, in
other embodiments, the method may be implemented using other
suitable systems. In step 310, valve pin 42 having distal portion
42a with first diameter D.sub.1 and mid-portion with second
diameter D.sub.2 smaller than the first diameter is provided. As
illustrated in FIG. 2, valve pin 42 may be provided as part of
injection nozzle 18 (also referred to as nozzle assembly 18). In
some embodiments, diameter D.sub.1 of distal portion 42a is about
the same as a diameter D.sub.3 of an aperture of a tip 38 of the
nozzle. As illustrated in FIG. 4, positioning valve pin distal
portion 42a in the aperture of nozzle tip 38 may prevent a
polymeric material stream from exiting through an output portion 39
of nozzle tip 38.
[0041] Step 320 includes providing mold 2400 defining cavity 22
corresponding to a shape of a resulting plastic article. Mold 2400
has recess 23 aligned with gate 20 of mold 2400, extending into
mold 2400, and configured to receive valve pin distal portion 42a
when distal portion 42a extends beyond gate region 21. FIG. 4 shows
injection nozzle 18 in contact with mold 2400 with the distal
portion 42a of the valve pin extending beyond gate region 21 and
into recess 23. The valve pin includes an aperture forming region
42d in the valve pin distal portion 42a.
[0042] In step 330, a combined polymer plastic stream 70, which
includes a first polymeric material 72 and a second polymeric
material 74, is formed in injection nozzle 18. In FIGS. 1 and 4-7,
first polymeric material 72 is indicated with dots and in FIGS. 1
and 5-7 second polymeric material 74 is indicated with solid
shading for illustrative purposes. One of skill in the art will
recognize that either or both of first polymeric material 72 and
second polymeric material 74 may have an appearance that is
translucent, transparent, opaque, uniform, non-uniform, or any
combination of the aforementioned.
[0043] In step 340, distal portion 42a of the valve pin is advanced
into recess 23 until mid-portion 42b of the valve pin at least
partially extends into gate region 21 of cavity 22. As illustrated
in FIG. 5, a flow path for the combined polymer stream 70 into
cavity 23 is established when valve pin mid-portion 42b at least
partially extends into gate region 21. Combined polymer stream 70
enters cavity 22 by flowing between a surface of cavity 22 at gate
20 and a surface of valve pin mid-portion 42b. In some embodiments,
at least a portion of valve pin mid-portion 42b is heated to
facilitate flow of combined polymer stream 70 past mid-portion 42b
and into cavity 22. During injection into the cavity, the valve pin
mid-portion 42b should be at an elevated temperature with respect
to the cavity 2400 (e.g., at a temperature near the polymer
temperature in the nozzle) to facilitate flow of polymer past the
mid-portion 42b when filling the cavity. For example, if the
polymer temperature in the nozzle is 230.degree. C., the
temperature of the valve pin mid-portion may be at least
200.degree. C. In many embodiments, valve pin mid-portion 42b has a
higher temperature than the aperture forming portion 42d of the
valve pin while combined polymeric stream 70 is being injected into
cavity 22. In many embodiments, valve pin mid-portion 42b is heated
by conductive heat transfer from nozzle tip 38 and by heat transfer
from the flowing combined polymer stream 70. In some embodiments,
valve pin 42 may be heated by electrical heating elements embedded
or attached to the valve pin 42.
[0044] As illustrated in FIG. 5, a leading edge 70a of the combined
polymeric stream may include only one polymeric material with a
leading edge 74a of the second material portion behind a leading
edge of the first material portion 72a. As illustrated in FIG. 6,
in some embodiments, after combined polymer stream 70 enters cavity
22 and substantially fills cavity 22, combined polymer stream 70
may become a stream including the first material 72, but not second
material 74 creating a trailing edge 74b of the first material
stream.
[0045] After mold 2400 has been filled or substantially filed with
the combined polymer stream, as shown in FIG. 6, the injected
combined polymer material 70 begins to cool and set. As shown in
FIG. 7, before the injected combined polymer material 70 fully
sets, valve pin distal portion 42a is partially withdrawn from
recess 23 and into gate region 21 of mold 2400 forming an aperture
120 at gate region 21 of the resulting molded plastic article 110
(see step 350 of FIG. 3). As illustrated in FIG. 7, formed aperture
120 coincides with the aperture forming region 42d of the valve
pin.
[0046] After the valve pin distal portion 32a is partially
withdrawn from recess 23 into gate region 21, the aperture forming
region 42d of the valve pin must reach an average temperature below
the solidification temperature of the polymer stream to form the
aperture. For example, in some embodiments, the aperture forming
region 42d may need to reach an average temperature of no more than
10.degree. C. to 100.degree. C. above the temperature of mold 2400.
In some embodiments having inner and outer layers of PP, the
temperature of the aperture forming region 42d may reach as high as
between 20.degree. C. to 40.degree. C. below the melting
temperature of PP when forming the aperture.
[0047] In some embodiments, at least some of distal portion 42a
(e.g., aperture forming region 42d) is cooled before being
withdrawn and/or is cooled while being withdrawn. In some
embodiments, valve pin distal portion 42a is cooled by contact with
mold portion 2400b during injection of polymer into the cavity as
shown in FIGS. 5 and 6. A separation (labeled L.sub.3) between the
higher temperature valve pin mid-portion 42b, which is in contact
with the flowing polymer stream 70, and the lower temperature
aperture forming portion 42d, which is in contact with the mold
2400, helps to maintain the temperature difference between the
valve pin mid-portion 42b and the aperture forming region 42d.
Increasing the size of the separation L.sub.3 makes the temperature
difference easier to maintain, but it increases the distance that
the valve pin 42 must be withdrawn from the injection position to
form the aperture.
[0048] As shown in FIG. 5 during injection, the aperture forming
region 42d is cooled by heat flowing laterally into the mold
portion 2400b as indicated by arrows A.sub.1, and by heat flowing
along the valve pin and then laterally into the mold portion 2400b
as indicated by arrows A.sub.2. The extension (labeled L.sub.2) of
the valve pin distal portion 42a beyond the aperture forming region
42d aids in conducting heat away from the aperture forming region
42d. In some embodiments, the valve pin distal portion 42a may have
a beveled distal end 42e to aid in aligning the distal portion 42a
with the recess 23. The total length of the distal end portion 42a
is labeled L.sub.1 herein.
[0049] As shown in FIG. 7, the heat absorbed by the aperture
forming region 42d during forming of the aperture of the molded
article must be transferred to the mold 2400b, 2400a to maintain
the temperature of the aperture forming region 42d in a suitable
temperature range (e.g., 10.degree. C. to 100.degree. C. above the
temperature of mold 2400). While the aperture is being formed, heat
flows from the aperture forming region 42d along the valve pin 42
away from the nozzle and laterally outward through contact with the
mold portion 2400b as indicated by arrows A.sub.2, and flows along
the valve pin toward the nozzle and laterally outward through
contact with the mold portion 2400a as indicated by arrows
A.sub.3.
[0050] The lengths L.sub.1, L.sub.2, L.sub.3, the diametrical
clearance (too small to be shown) between the valve pin distal
portion 42a and the diameters of recess 23 and of gate 20, the
thickness of the polymer in the aperture region h.sub.a, and the
temperature of the polymer in the aperture region will affect the
heat absorbed by the aperture forming region 42d during step 350.
The required time for the aperture forming region 42d to return to
the desired temperature range is also affected by the same
variables. These variables may be adjusted to shorten the time
required for aperture formation and to achieve an acceptable
overall cycle time. After aperture forming region 42 reaches the
desired temperature range and the aperture is formed, the valve pin
42 may return to the position shown in FIG. 4, the mold opens and
the plastic article is ejected from the mold (e.g., mechanically or
pneumatically).
[0051] FIG. 8 shows resulting plastic article 110 after the cavity
has been filled, the valve pin distal portion has been withdrawn
from the gate region of the cavity forming molded aperture 120, and
resulting plastic article 110 has been released from the mold.
Resulting plastic article 110 includes a sidewall portion 132,
molded aperture 120 in a gate region 121 of the article, and a
shoulder portion 130 disposed between sidewall portion 132 and gate
region 121. As illustrated in FIG. 8, resulting plastic article 110
may include an inner layer 170 and an outer layer 172 of the first
polymeric material, which together generally conform to the desired
end shape of the final container or article, accounting for
manufacturing requirements (e.g., thermal expansion/contraction) as
is known. In some embodiments, the inner layer 170 and the outer
layer 172 may be referred to as the skin of the article. The second
polymeric material forms interior layer 174, which may be referred
to as a "core layer," disposed between inner layer 170 and outer
layer 172. Interior layer 174 may be a barrier layer, a gas
scavenging layer, and/or a desiccant layer. For example, a gas
barrier material of interior layer 174 may be EVOH or other
suitable materials, which are known or may become known, that
sufficiently prevent gases, for example, oxygen, from permeating
through the article, i.e., from the outside to the inside and vice
versa. Though PET, PP and EVOH are commonly used materials, it
should be understood what other suitable materials may be used, and
that the various embodiments are suitable for use with other
polymeric materials.
[0052] Resulting article 110 has a first end portion 112, which
includes a gate region 121, and an injection-molded aperture 120,
and a second end portion 114. In some embodiments, the second end
portion of the article may include a sealing surface. For example,
second end portion 114 of article 110 includes a flange 134 with a
sealing surface 135. In different embodiments, various types of
sealing surfaces may be employed (e.g. surfaces configured for
heat-sealing and crimping, threaded surfaces, etc.). In different
embodiments, the second end portion of the article may have a
structure other than a flange (e.g., an open end tube to be welded
closed such as a toothpaste tube). Various methods may be used for
sealing the sealing surface 135 (e.g., heat-sealing, crimping,
threading, and other known methods).
[0053] The amount that the interior layer extends through the
article varies for different embodiments. In some embodiments the
interior layer may not extend throughout the article. For example,
in article 110 of FIG. 8, interior layer 174 extends from sidewall
portion 132 to shoulder portion 130 and terminates in the shoulder
portion at 174b before gate region 121. Interior layer 174 also
extends from sidewall portion 132 to flange 134 and terminates at
174a without extending to an edge of flange 134. In some
embodiments, an interior layer may extend through the shoulder
portion and into the gate region(e.g., see FIGS. 10 and 11
described below) or may terminate in the sidewall portion.
[0054] Throughout the figures, thicknesses are exaggerated for
illustrative purposes. For example, a thickness of sidewall portion
25 of cavity 23 is exaggerated in FIGS. 1 and 4-7. In FIGS. 7 and
8, a thickness of sidewall portion 132 of resulting plastic article
110 is exaggerated. As another example, thicknesses of inner layer
170 outer layer 172 and interior layer 174 are exaggerated in FIGS.
7 and 8. Further, relative thicknesses are not representative. For
example, in FIGS. 7 and 8, the thickness of interior layer 174 is
exaggerated relative to thicknesses of inner layer 170 and outer
layer 172.
[0055] In some embodiments, a resulting plastic article may be
configured for use as a container (e.g., for containing food,
beverages, pharmaceutical, nutraceuticals and/or other
gas-sensitive products). For example, FIG. 9 shows plastic article
110 incorporated into a container 210 for storing a food (e.g.,
ground coffee beans). Container 210 may include a first seal 212
that seals the first end portion 112 of the article. Container 210
may include a second seal 214 that seals the second end portion 114
of the article on sealing surface 135. Various methods may be used
for sealing the sealing surface 135 (e.g., heat-sealing, crimping,
threading, and other known methods). First seal 212, second seal
214, and sidewall portion 110, enclose a sealed container volume
216 for storing a product.
[0056] Substantially all of the surface area of the article exposed
to the product may include an interior layer. As used herein, the
term "substantially" or "substantially fully" means 95%-100%
coverage of the interior layer across the entire surface area of
the article exposed to the container volume for storing product. As
illustrated in FIG. 9, interior layer 174 need not extend to an
edge of flange 134 or to gate region 121 because those portions of
the article 110 are separated from the container volume 216 for
storing product by the first seal 212 and by the second seal 214
respectively.
[0057] FIG. 10 shows a variation of the container 210 that includes
a smaller first seal 212' for the first end, which is external to
the aperture 120. In this embodiment, the core layer 174' extends
through the shoulder portion 130' of the article and terminates
174b' closer to the aperture 220', specifically within a diameter
of the external first seal 212', which is disposed on a sealing
surface 136'. The external first seal 212' and the extended core
layer 174' effectively seal the first end of the article. In some
embodiments, the external first seal 212' is punctured or removed
prior to use.
[0058] A container may include additional functional features, some
of which are illustrated by the container 210 of FIG. 9. For
example, container 210 may include a filter 217 for filtering a
product (e.g., for filtering coffee when water or steam is injected
into dry coffee held in container volume 216 through second seal
214). Container 210 may include a piercing element 218 configured
to pierce first seal 212 when first seal 212 bulges due to
increasing internal pressure in container volume 216.
[0059] FIG. 11 depicts another container including a plastic
article formed in accordance with various embodiments. A container
405 (e.g., a tube for toothpaste, ointment, or other viscous
product) includes a multilayer co-injection-molded plastic article
410 formed with a first end portion 412 including a gate region 421
having an injection-molded aperture 420, and a second end portion
414 that is initially open to permit filling container 405 with
product. Plastic article 410 includes an inner layer 470 and an
outer layer 472 of a first polymeric material, which may be
referred to as skin layers. An interior layer 474 including a
second polymeric material is disposed between inner layer 470 and
outer layer 472. Second polymeric material may be a barrier
material, an oxygen scavenging material, a recycled material,
and/or other performance-enhancing or cost-reducing material.
[0060] The container may include one or more seals for sealing a
first end portion and/or a second end portion of the container. For
example, container 405 includes a first seal 415 on a sealing
surface 436 for sealing injection-formed aperture 420 of first end
portion 412 of the container. Container 405 also includes a second
seal 415 in a sealing surface 435 for sealing the initially open
second end portion 414 of the container. The first seal and the
second seal may be any suitable seal including, but not limited to,
a heat seal, a crimp seal, an adhesive seal, a foil seal, a plug,
etc. For example, first seal 415 is a foil seal adhered to gate
region 421 and second seal 417 is a heat/crimp seal. First seal
415, second seal 417, sidewall portion 432, shoulder portion 430,
and gate region 421 form a sealed volume 416 for enclosing a
product. For an inner layer 470 and an outer layer 472 of a
relatively gas permeable polymer, such as PP or PE, it may be
desirable for the interior layer 474 to extend through the shoulder
portion 430 and terminate proximal to the aperture seal 415 as
shown in FIG. 11.
[0061] As shown in FIG. 12, an interior layer 474' of the second
material need not extend throughout portions of article 410 exposed
to sealed volume 416 for relatively gas impermeable polymers such
as PET. FIG. 12 depicts a variation of the container 410 in which
the interior layer 474' terminates in the shoulder portion 430' of
the article. In some embodiments including a less gas permeable
skin material (e.g., PET), the shoulder portion 430' of the article
has a substantially larger wall thickness T.sub.1 than that of the
sidewall portion T.sub.2, and the larger wall thickness provides a
sufficient barrier to prevent gas permeation in the shoulder
portion 430' of the article.
[0062] FIG. 13 illustrates an exemplary nozzle assembly suitable
for practicing embodiments taught herein. Nozzle assembly 18
includes an inner combining means 30, a middle combining means 32,
and an outer combining means 34. Nozzle assembly 18 further
includes nozzle body 36 and nozzle tip 38. Inner combining means
30, middle combining means 32, outer combining means 34, nozzle
body 36, and nozzle tip 38 cooperatively combine to form a number
of conical, annular, and axial passages and channels in nozzle
assembly 18. The nozzle assembly 18 is well suited for use in a
co-injecting system, for example system 1000, for forming a plastic
object having two or more layers.
[0063] Inner combining means 30 includes a first inlet 46 to
receive a first polymeric material 64, such as a skin material
(i.e., inner and outer layer material), and a second inlet 44 to
receive a second polymeric material 66, such as a core material
(i.e., interior layer material). The inner combining means 30
further includes a through bore 40 configured to receive a valve
pin 42. The through bore 40 extends through the middle combining
means 32, and through a portion of the outer combining means 34 to
allow the valve pin 42 to move in an axial direction along a
longitudinal axis of the nozzle assembly 18. Through bore 40 has an
inner wall diameter that varies along a central longitudinal axis
of the nozzle assembly 18. Valve pin 42 is movable in an axial
direction along the central longitudinal axis of nozzle assembly 18
to assist in controlling the flow of the first polymeric material
64 and second polymeric material 66 through nozzle assembly 18 and
into mold 24.
[0064] Middle combining means 32 cooperatively engages with the
inner combining means 30 form a portion of the plurality of annular
flow channels in nozzle assembly 18. Middle combining means 32
receives from channel 37 the first polymeric material 64 and
receives from channel 41 the second polymeric material 66 to
manipulate the flow of each of the polymeric materials through a
plurality of annular fluid carrying passages or channels. The flow
manipulation carried out by middle combining means 32 initiates the
creation of an outer material stream 58 and an inner material
stream 56 that together encapsulate an interior material stream
60.
[0065] The middle combining means 32 when coupled with the inner
combining means 30 forms a wrapped-coat-hanger die 31 that
circumferentially extends around the through bore 40 and valve pin
42. Wrapped-coat-hanger die 31 provides annular fluid flow passage
48 with a uniform melt distribution of the first polymeric material
64. Annular fluid flow passage 48 channels an annular flow stream
of the inner material stream 56 into stream combination area 54
through an orifice.
[0066] Outer combining means 34 cooperatively engages with middle
combining means 32 to form one or more fluid carrying passages or
channels to manipulate the second polymeric material 66 forming an
interior layer of the resulting plastic object. The outer combining
means 34 when coupled with the middle combining means 32 forms a
wrapped-coat-hanger die 33 that circumferentially extends around
inner material stream 56, through bore 40, and valve pin 42.
Wrapped-coat-hanger die 33 provides conical fluid flow passage 52
with a uniform melt distribution of the second polymeric material
66. Conical flow passage 52 feeds an annular stream of the second
polymeric material 66 into stream combination area 54 through
another orifice.
[0067] The outer combining means 34 cooperatively engages with
nozzle body 36. The outer combining means 34 when coupled with the
nozzle body 36 forms wrapped-coat-hanger die 35 that
circumferentially extends around the interior layer stream 52, the
inner layer stream 56, the through bore 40, and the valve pin 42.
Wrapped-coat-hanger die 35 provides radial fluid flow passage 50
with a uniform melt distribution of the first polymeric material
64. Radial fluid flow passage 50 feeds stream combination area 54
with a flow of first polymeric material 64 through an orifice. The
first polymeric material 64 fed into the stream combination area 54
through the orifice forms the outer layer of a resulting molded
object.
[0068] Fluid flow passages 48, 50, and 52 feed stream combination
area 54 with the outer material stream 58, the inner material
stream 56, and the interior material stream 60. A portion of the
nozzle tip 38, a portion of the outer combining means 34, a portion
of the middle combining means 32, and a portion of the valve pin
42, in combination form the stream combination area 54. Stream
combination area 54 combines in a simultaneous or near simultaneous
manner the outer material stream 58 received from the fluid flow
passage 50, the inner material stream 56 received from the fluid
flow passage 48, and the interior material stream 60 received from
the fluid flow passage 52 to form annular output stream.
[0069] The channels, bores and passageways of the inner combining
means 30, the middle combining means 32 and the outer combining
means 34 and more specifically the channels, bores and passageways
associated with the formation and the flow of inner and outer layer
material in the nozzle assembly 18 may be sized, defined, adapted
and configured to control or produce a desired volumetric flow
ratio as discussed above. In this manner, the valve pin 42 may
remain in a fixed position and does not need to be moved to control
or form a particular volumetric flow ratio. In other words, the
nozzle assembly 18 has a channel configuration and structure to
output a desired or selected volumetric flow ratio without the need
of an associated controller or microprocessor. In some exemplary
embodiments, the valve pin 42 may be controlled by a controller or
microprocessor to control the volumetric flow ratio.
[0070] The annular output stream 49 flows from the stream
combination area 54 through fluid flow passage 62 to output portion
39 of nozzle assembly 18. Fluid flow passage 62 has an annular
inner passage that radially extends about through bore 40 and
axially extends from the stream combination area 54 to the output
portion 39. The output portion 39 communicates with a gate of a
mold, such as one of gates 20A-20D.
[0071] As explained above, by advancing a mid-portion of the valve
pin 42b into a gate region of a mold cavity allowing a co-polymer
stream to fill the cavity, and then withdrawing the valve pin
distal portion 42a from a recess of the mold through the gate
region of the mold cavity after the mold is filled or substantially
filled, an injection-molded aperture is produced in a gate region
of the resulting article. As illustrated in FIG. 13, the same valve
pin 42 may be used to produce an article without an aperture in the
gate region by withdrawing the valve pin 42 to allow a co-polymer
stream to exit the output portion, as opposed to advancing the
valve pin.
[0072] The annular output stream 49 formed by the stream
combination area 54 has an outer annular skin layer and an inner
annular skin layer formed of the first polymeric material 64, and
an interior or core annular layer formed of the second polymeric
material 66. The inner and outer skin layers of the first polymeric
material 64 may each have a substantially like cross sectional area
as the materials flow through the fluid flow passage 62 to the
output portion 39. Typical ratios of inner to outer volumetric flow
rate are between 80:20 and 20:80. The exact ratio is chosen to
locate the interior layer at the desire position within the wall of
the molded article. The inner and outer skin layers of the first
polymeric material 64 encapsulate the interior layer of the second
polymeric material 66, which forms a core portion of a resulting
plastic object. Upon injection from the nozzle assembly 18, the
combined polymeric stream 49, includes an interior stream that
flows along concentric or annular streamlines between the inner and
outer polymeric streams.
[0073] FIG. 14 illustrates an exemplary computing environment
suitable for practicing exemplary embodiments taught herein. The
environment may include a co-injection control device 900 coupled,
wired, wirelessly or a hybrid of wired and wirelessly, to
co-injection system 1000. The co-injection control device 900 is
programmable to implement executable Flow Control Code 950 for
forming a barrier layer and/or scavenger layer. Co-injection
control device 900 includes one or more computer-readable media for
storing one or more computer-executable instructions or software
for implementing exemplary embodiments. The computer-readable media
may include, but are not limited to, one or more types of hardware
memory, non-transitory tangible media, etc. For example, memory 906
included in the co-injection control device 900 may store
computer-executable instructions or software, e.g., instructions
for implementing and processing every module of the executable Flow
Control Code 950. Co-injection control device 900 also includes
processor 902 and, one or more processor(s) 902' for executing
software stored in the memory 906, and other programs for
controlling system hardware. Processor 902 and processor(s) 902'
each can be a single core processor or multiple core (904 and 904')
processor.
[0074] Virtualization may be employed in co-injection control
device 900 so that infrastructure and resources in the computing
device can be shared dynamically. Virtualized processors may also
be used with the executable Flow Control Code 950 and other
software in storage 916. A virtual machine 914 may be provided to
handle a process running on multiple processors so that the process
appears to be using only one computing resource rather than
multiple. Multiple virtual machines can also be used with one
processor.
[0075] Memory 906 may include a computer system memory or random
access memory, such as DRAM, SRAM, EDO RAM, etc. Memory 906 may
include other types of memory as well, or combinations thereof.
[0076] A user may interact with co-injection control device 900
through a visual display device 922, such as a computer monitor,
which may display the user interfaces 924 or any other interface.
The visual display device 922 may also display other aspects or
elements of exemplary embodiments, e.g., materials databases,
production information, etc. Co-injection control device 900 may
include other I/O devices such a keyboard or a multi-point touch
interface 908 and a pointing device 910, for example a mouse, for
receiving input from a user. The keyboard 908 and the pointing
device 910 may be connected to the visual display device 922.
Co-injection control device 900 may include other suitable
conventional I/O peripherals. Co-injection control device 900 may
further include a storage device 916, such as a hard-drive, CD-ROM,
or other non-transitory computer readable media, for storing an
operating system 918 and other related software, and for storing
executable Flow Control Code 950.
[0077] Co-injection control device 900 may include a network
interface 912 to interface to a Local Area Network (LAN), Wide Area
Network (WAN) or the Internet through a variety of connections
including, but not limited to, standard telephone lines, LAN or WAN
links (e.g., 802.11, T1, T3, 56kb, X.25), broadband connections
(e.g., ISDN, Frame Relay, ATM), wireless connections, controller
area network (CAN), or some combination of any or all of the above.
The network interface 912 may include a built-in network adapter,
network interface card, PCMCIA network card, card bus network
adapter, wireless network adapter, USB network adapter, modem or
any other device suitable for interfacing authorization computing
device 900 to any type of network capable of communication and
performing the operations described herein. Moreover, co-injection
control device 900 may be any computer system such as a
workstation, desktop computer, server, laptop, handheld computer or
other form of computing or telecommunications device that is
capable of communication and that has sufficient processor power
and memory capacity to perform the operations described herein.
[0078] Co-injection control device 900 can be running any operating
system such as any of the versions of the Microsoft.RTM.
Windows.RTM. operating systems, the different releases of the Unix
and Linux operating systems, any version of the MacOS.RTM. for
Macintosh computers, any embedded operating system, any real-time
operating system, any open source operating system, any proprietary
operating system, any operating systems for mobile computing
devices, or any other operating system capable of running on the
computing device and performing the operations described herein.
The operating system may be running in native mode or emulated
mode.
[0079] Flow Control Code 950 includes executable code executable by
the processor 902 to control the co-injection system 1000 to
control a position of the valve pin 42 for controlling flow of the
co-polymer stream into the mold cavity and forming an aperture in a
gate region of a resulting multi-layer plastic article. The
executable code executable by the processor 902 may also control a
temperature of at least portions of the gate pin 42, and control a
temperature of at least portions of the mold 2400. The executable
code may be executable by the processor 902 to selectively control
a volumetric flow volume of the inner and outer polymeric streams,
control a position of the interior core material stream relative to
a velocity flow front of the combined polymeric stream, and control
extrusion start time of the interior core stream relative to the
extrusion start time of the inner and outer polymeric streams.
Co-injection systems taught herein facilitate the co-injection
molding of container such as food or beverage containers.
[0080] As may be recognized by those of ordinary skill in the
pertinent art based on the teachings herein, numerous changes and
modifications may be made to the above-described and other
embodiments of the present disclosure without departing from the
spirit of the invention as defined in the appended claims.
Accordingly, this detailed description of embodiments is to be
taken in an illustrative, as opposed to a limiting, sense. Those
skilled in the art will recognize, or be able to ascertain using no
more than routine experimentation, many equivalents to the specific
embodiments of the described herein. Such equivalents are intended
to be encompassed by the following claims.
* * * * *