U.S. patent application number 10/869260 was filed with the patent office on 2004-11-11 for method for anchoring an elastomer into a thermoplastic during injection molding.
This patent application is currently assigned to Spotless Plastics Pty. Ltd.. Invention is credited to Olk, Olaf, Pena, Ralph H..
Application Number | 20040222254 10/869260 |
Document ID | / |
Family ID | 22323967 |
Filed Date | 2004-11-11 |
United States Patent
Application |
20040222254 |
Kind Code |
A1 |
Olk, Olaf ; et al. |
November 11, 2004 |
Method for anchoring an elastomer into a thermoplastic during
injection molding
Abstract
A molded plastic garment hanger constituted from first and
second plastic materials which are fused and mechanically bonded to
form a composite garment hanger. A coinjected plastic member formed
of the second plastic material is molded into the plastic body
member formed of the first plastic material, and is secured thereto
by a plume of the second plastic material of the coinjected plastic
member which is formed as the second plastic material is coinjected
and breaches the surface of the first plastic material of the
molded plastic body member which is not completely set and
hardened, such that the plume of the second plastic material
extends into and is secured and anchored into the first plastic
material. A method and apparatus for co-injection molding of
plastic materials for the formation of the plastic garment hanger
construction are also disclosed.
Inventors: |
Olk, Olaf; (Hauppauge,
NY) ; Pena, Ralph H.; (Fletcher, NC) |
Correspondence
Address: |
SCULLY SCOTT MURPHY & PRESSER, PC
400 GARDEN CITY PLAZA
GARDEN CITY
NY
11530
|
Assignee: |
Spotless Plastics Pty. Ltd.
Victoria
AU
|
Family ID: |
22323967 |
Appl. No.: |
10/869260 |
Filed: |
June 16, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10869260 |
Jun 16, 2004 |
|
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10108775 |
Mar 28, 2002 |
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6772923 |
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Current U.S.
Class: |
223/85 |
Current CPC
Class: |
B29C 45/1676 20130101;
B29C 45/1635 20130101; B29C 45/1657 20130101; B29C 2045/1668
20130101; A47G 25/30 20130101; B29L 2031/735 20130101 |
Class at
Publication: |
223/085 |
International
Class: |
A41D 027/22 |
Claims
1-9. (Cancelled).
10. A method of coinjection molding a composite plastic garment
hanger formed of first and second plastic materials, comprising:
positioning a retractable mold curve in a first position in a
garment hanger mold cavity of a garment hanger mold to define a
first mold cavity, the surface of the retractable mold core
defining a pattern to create a pattern within the first mold
cavity; injecting a first plastic material into the first mold
cavity to form a molded plastic body member of the composite
plastic garment hanger; cooling and partially setting the first
plastic material; retracting the retractable mold core to a second
position in the mold cavity to define, in combination with the
first plastic material, a second mold cavity; injecting a second
plastic material into the second mold cavity to form a second
portion of the composite plastic garment hanger, wherein when the
second plastic material is injected into the second mold cavity,
the pressurized second plastic material breaches the surface of the
partially set and hardened first plastic material of the plastic
body member and forms a plume of the second plastic material which
extends into and displaces the relatively unset and not hardened
first plastic material to anchor and secure the plume of the second
plastic material into the first plastic material.
11. The method of claim 10, wherein the mold cavity defines an
enlarged volume portion of the plastic garment hanger in a position
adjacent to the retractable core, and following cooling and
partially setting of the first plastic material, the surfaces of
the first plastic material are partial set and hardened, but the
first plastic material in the enlarged volume portion remains
relatively unset and not hardened, and when the second plastic
material is injected into the second mold cavity, the pressurized
second plastic material breaches the surface of the partially set
and hardened first plastic material and forms a plume of the second
plastic material which extends into and displaces the relatively
unset and not hardened first plastic material in the enlarged
volume portion, to anchor and secure the plume of the second
plastic material into the first plastic material in the enlarged
volume portion.
12. The method of claim 10, wherein the retractable mold core
defines a pattern of transversely extending ribs which mold
transversely extending bottom ribs defined in the bottom of the
recess when it is in the first position, and mold transversely
extending top ribs of the non-slip strip when it is in the second
position.
13. The method of claim 12, wherein the pattern of transversely
extending ribs does not include any undercuts in the pattern.
14. The method of claim 10, wherein the first plastic material is
injected through one or more primary injection inlets into the
garment hanger mold, during which a projection on the retractable
mold core covers and seals off a second injection inlet, through
which the second plastic material forming the non-slip strip is
subsequently injected.
15. The method of claim 14, wherein the projection on the
retractable mold core is positioned on one side of the rectangular
recess near the center of the length thereof, and extends
downwardly into one side upper edge to form a generally
rectangularly shaped access aperture on one side of and near the
center of the length of the rectangular recess, to allow the second
plastic material to be injected through the second injection inlet
and through the access aperture to form the non-slip strip after
the retractable mold core is retracted to the second position.
16. The method of claim 10, wherein the garment hanger mold
includes first and second symmetrical mold members, each of which
form one half of the garment hanger mold cavity.
17. The method of claim 10, wherein the retractable mold core is
translatable between the first and second positions by a linear
actuator.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to coinjected composite
garment hangers, and more particularly pertains to a molded plastic
garment hanger constituted from two different plastic materials
which are coinjected to form a composite garment hanger. Moreover,
the subject invention also relates to a novel method for
co-injection molding of plastic materials for the formation of a
composite plastic garment hanger.
BACKGROUND OF THE INVENTION
[0002] In the garment manufacturing and retail industry, plastic
garment hangers are widely employed for the purpose of shipping and
displaying garments. The plastic garment hangers are frequently of
the inexpensive ship-on type whereby the garment is shipped from
the manufacturer or wholesaler to the retailer while suspended from
the hanger. Generally, such garment hangers are inexpensive
single-piece or unitary molded plastic structures which are adapted
to be either discarded at the time of sale, or returned to the
garment manufacturer, or provided to a customer free of charge in
conjunction with the purchase of the garment suspended
therefrom.
[0003] Garment hangers of that type may be simply constructed as
molded plastic structures incorporating a unitary plastic or
separate metal central hook portion adapted to be suspended from a
suitable support, such as a garment rack or the like, with a hanger
body having arms extending in opposite directions from the base of
the hook portion so as to facilitate a garment to be suspended
therefrom. When needed for a specific use, the opposite or distal
ends of the body portion or arms may be formed with suitable grip
slots or clip members to enable the attachment of various kinds of
garments thereto, such as underwear, slips, brassieres, multiple
garments, and the like.
[0004] The prior art also includes garment hangers for coats,
blazers and other heavier garments which are fitted with pads or
rubber strips along the shoulder portions thereof, or non-slip
adhesive coatings on the pants bar to assist in retaining the
garment on the hanger.
[0005] U.S. Pat. No. 4,655,867 to Berkovits discloses a garment
hanger having a non-slip strip of resilient material adhesively
secured to the shoulder portions of the hanger.
[0006] U.S. Pat. No. 4,606,482 to McHugh discloses a rod-type
garment hanger having a preformed sleeve of non-slip protective
material which is slipped over the rod portions of the hanger to
assist in retaining a garment on the hanger.
[0007] U.S. Pat. No. 4,058,241 to Craig discloses a tightly braided
cover which is plaited around the periphery of a garment hanger to
provide protection for the garment and to prevent garment slippage
from the hanger.
[0008] U.S. Pat. No. 5,020,705 to Garrison discloses a garment
clamping hanger which has garment gripping pads molded of a
synthetic rubber which has a high coefficient of friction when
firmly pressed against a fabric and avoids marking or adhering to
the fabric of a garment.
[0009] Some prior art garment hangers, such as Garrison U.S. Pat.
No. 5,020,705, have incorporated a coating of particles of high
friction material such as rubber to improve the garment gripping
capabilities thereof. Hangers using high friction gripping pads
have experienced several problems. Functionally, one of the major
problems has been that of delamination of the gripping pad from the
hanger. This problem becomes more acute when the hangers are used
for heavy garments and even more so when the hanger is intended for
repeated reuse or for transportation where it has to sustain the
additional strain of repeated, abrupt, vertical movements often
experienced in transit.
[0010] Another factor which has materially restricted their use is
cost. Making the hanger in two separate operations, that is, first
assembling or molding the hanger body and later bonding the garment
gripping pads to the body involves labor costs which are not
acceptable in the highly competitive hanger manufacturing business.
Another factor has been the problem of developing a pad which will
provide the necessary gripping function and, at same time, have
sufficient body durability and strength to withstand the rigors and
demands of commercial usage. Past experience has indicated that
rubber pads, either natural or synthetic, which have the required
frictional gripping ability are not structurally capable of
withstanding either repeated or rough usage. Heretofore, when the
material had durability, it lacked the necessary frictional
characteristics and vice versa.
[0011] The prior art also discloses numerous kinds of apparatus and
methods for molding two-component plastic materials by a two-step
or co-injection process. However, these have not been specifically
applied to the production of two-component or composite plastic
garment hangers of the types considered herein.
[0012] U.S. Pat. No. 4,416,602 to Neumeister discloses an injection
molding apparatus for manufacturing articles from different types
of plastic materials, in which a first plastic material is injected
into a mold to form a frame member or the like, and thereafter
subsequent to cooling and solidifying of the molten plastic
material, a second plastic material is injected into the cavity of
the mold so as to form an insert within an aperture of the frame
member provided by the first plastic material, thereby fusing the
plastic materials and forming a mechanical bond therebetween.
[0013] In U.S. Pat. No. 5,020,705 to Garrison, garment gripping
pads of hanger clips are molded substantially simultaneously with
the hanger so as to chemically bond with the material of the
hanger. The hanger is molded with the front and rear jaws of the
clip in an open position. When the mold is closed each cavity in
which a pad is to be formed is occupied by a cam. While the cams
are occupying the cavities for the pads, the hanger forming resin
is injected into the mold to fill the entire mold except for the
spaces occupied by the cams. After the resin has sufficiently set,
the cams occupying the pad forming cavities are withdrawn
(upwardly) and the resin to form the pads is injected through an
opening 27. To avoid resin migration, the opening is very small and
a tab gate 47 is provided between the parting line and the opening
such that when the hanger is ejected from the mold, the resin is
sheared by the tab gate from the resin remaining in the
conduit.
[0014] Similar types of molding apparatus and methods are disclosed
in various patent publications, representative of which are U.S.
Pat. No. 4,711,621 to Schomblond disclosing a mold for producing
composite bodies from different plastic materials, U.S. Pat. No.
4,335,068 to Hemery, and U.S. Pat. No. 3,577,596 to Bullard et
al.
SUMMARY OF THE INVENTION
[0015] The present invention relates to coinjected composite
plastic hangers, and a method of coinjection of the composite
plastic hangers. Various desirable attributes for hangers may be
created in a coinjected composite plastic hanger which are not
available to a hanger molded from a single plastic. The composite
plastic hanger can be formed with plastic coinjected members such
as integrally molded non-slip portions to retain garments on the
hangers.
[0016] The second plastic material for the plastic coinjected
member which is molded into the basic hanger structure is generally
produced in the same mold for producing the basic hanger structure
through a co-injection method, which is performed subsequent to the
initial molding and cooling of the basic hanger structure so as to
cause the plastic coinjected member to fuse and bond with the
contacting surfaces of the plastic material for the basic hanger
structure. This bond may be a mechanical bond, a plastic molded
bond, a fusion bond or a combination thereof, depending on the
plastics selected, and the relative injection, set and cool cycles
and times of the coinjection machine. This imparts a versatility to
the construction and utilization of such garment hangers inasmuch
as a single mold with a movable core can be employed for forming
the entire composite plastic garment hanger construction, and the
mold may be modified with regard to the formation of the plastic
coinjected member.
[0017] For this purpose, the subject invention also contemplates a
two-step molding procedure or, in essence, a co-injection plastic
molding method whereby plastic materials of different types and/or
colors may be readily employed so as to have a first plastic
material of a specified type and color form the basic hanger
structure, cooled to some extent within the mold so as to at least
partially solidify. Thereafter, a mold core is movable into a
position which uncovers an injection inlet for a further or second
plastic material which may be a different color and/or material
type, and through which the second plastic material is coinjected
to form the plastic coinjected member with a plume of the second
plastic material which extends into and is fused and bonded with
the plastic material of the basic hanger structure so as to provide
a permanent connection therebetween.
[0018] The present invention also provides a coinjected garment
hanger having a non-slip plastic material which is molded and
bonded to the shoulder portions of the hanger to prevent slippage
of a garment from the hanger.
[0019] Another object of the present invention is to provide a
coinjected composite plastic garment hanger which incorporates a
non-slip insert consisting of a second plastic material that is
softer and more adherent and stickier than the garment hanger body,
which insert is fused to the basic hanger structure so as to form a
fused plastic and mechanical bond with the first plastic material
constituting the basic garment hanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The foregoing and other objects of the invention may now be
more readily ascertained from the following detailed description of
preferred embodiments thereof, taken in conjunction with the
accompanying drawings, in which:
[0021] FIG. 1 illustrates a side elevational view of a composite
coinjected garment hanger pursuant to the present invention which
has a molded plastic body incorporating non-slip plastic inserts in
the shoulder portions thereof.
[0022] FIG. 2 illustrates a more detailed view of one half of the
coinjected garment hanger of FIG. 1, with the second half of the
garment hanger being generally a complementary mirror image of the
first half shown in FIG. 2.
[0023] FIG. 3 is a top plan view of the end of the non-slip insert
formed on the left projecting arm of the coinjected garment hanger
of FIGS. 1 and 2.
[0024] FIG. 4 is a cross sectional view of the hanger arm and
garment gripping pad taken along sectional arrows 4-4 in FIG.
2.
[0025] FIG. 5 is a cross sectional view of an alternative
embodiment of a hanger arm and garment gripping pad pursuant to the
present invention.
[0026] FIG. 6 illustrates a fragmentary schematic plan view of a
mold cavity for forming a composite coinjected plastic garment
hanger pursuant to the invention with a movable mold cote in a
first operative position.
[0027] FIG. 7 illustrates a view similar to FIG. 6 showing the mold
cavity with the movable mold core in a second operative position
for forming the composite coinjected plastic garment hanger of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring to the drawings in detail, FIG. 1 illustrates a
side elevational view of a composite coinjected plastic garment
hanger 10 constructed pursuant to the present invention. FIG. 2
illustrates a more detailed view of one half of the composite
coinjected garment hanger of FIG. 1, with the second half of the
garment hanger being generally a complementary mirror image of the
first half shown in FIG. 2. FIG. 3 is a top plan view of the end of
the non-slip plastic insert formed on the left projecting arm of
the garment hanger of FIGS. 1 and 2, and FIG. 4 is a sectional view
of the hanger arm and garment gripping non-slip plastic insert
taken along sectional arrows 4-4 in FIG. 2.
[0029] FIG. 1 illustrates a side elevational view of a composite
coinjected plastic garment hanger 10 incorporating non-slip plastic
inserts 30 on each shoulder of the hanger. The composite hanger has
a molded plastic body portion and a centrally located metal hook 12
arranged to suspend the hanger from a hanger support bar or the
like. The molded plastic body extends outwardly and downwardly from
the lower end of the hook member with outwardly extending arms 18,
20. Each of the arms 18, 20 has an integrally molded non-slip
plastic insert layer 30 which forms the upper top portion of the
shoulder of each of the hanger arms 18, 20.
[0030] The garment hanger 10 includes a central metal hook portion
12 which is theadedly engaged into an upwardly extending
cylindrical neck 14 defined in a central portion 16 of the hanger
body, and further includes a pair of coplanar oppositely extending
arms 18 and 20 for suspending one or more garments, as is well
known in the art. Each arm defines near the central top thereof a
longitudinally extending recess 22 having a central upper opening
24, the function of which is to receive therein straps or other
components of a garment to assist in supporting a garment on the
hanger, as is well known in the art. The distal ends of each of the
arms 18 and 20 may, if desired, be equipped with suitable garment
gripping or clip structures, for example as disclosed in U.S. Pat.
No. 4,623,079 to Tendrup et al., or alternatively may be of a
simple rounded end configuration to merely permit the hanging
suspension of a garment rather than fastening the garment to the
hanger. In an alternate embodiment, the central hook portion can be
integrally molded of plastic with the hanger body, as is well known
in the art.
[0031] The body of the garment hanger is generally strengthened and
reinforced by a wide flange 26 which extends across the thickness
of and generally around the outer perimeter of the garment hanger.
The flange 26 extends upwardly in a rounded fashion at the
hook-supporting neck 14, and extends around the central
hook-supporting section 16 of the hanger, and further extends
around the perimeter of each arm 18, 20 and around the perimeter of
each garment-receiving longitudinal recess 22. The central portion
of the garment hanger extending between the upper and lower flanges
26 is formed by a centrally positioned, relatively thin, vertically
extending web 28, as best shown in FIG. 4. The top and bottom wide
flanges 26 and the thin central web 28 form a construction similar
to an I beam, as best shown in FIG. 4, which provides structural
strength for the hanger and support for a garment.
[0032] In alternative embodiments, the body of the garment hanger
could have alternative cross section constructions, such as an M
shaped cross section as illustrated in FIG. 5, or some other
reinforcing structural cross section such as a C shaped cross
section.
[0033] The garment hanger includes a garment gripping non-slip
plastic insert or pad 30 which is molded into and mechanically and
fusedly bonded into the top of each end of the oppositely directed
shoulder portions of the arms 18, 20. The garment gripping pads 30
are co-injected of a second plastic material with the primary
plastic material which forms the basic hanger body structure of the
garment hanger. The garment gripping pads 30 are formed of a softer
and more resilient and adherent second plastic material than the
first primary plastic material, such that a-garment supported on
the garment gripping pads is more frictionally and resistively
gripped by, and less likely to slip or slide relative to, the
garment gripping pads.
[0034] FIGS. 2, 3 and 4 taken together illustrate the shape and
nature of each garment gripping pad 30 and its interrelationship
with the hanger arm 18, 20. Each garment gripping pad 30 includes a
number, e.g. 8, of spaced, transversely extending ribs 32 which are
designed to increase the garment gripping ability of the garment
gripping pad. Each transversely extending rib 32 defines a
generally semicircular shaped top, as illustrated in FIGS. 1 and 2,
although other shapes are also possible in alternative embodiments,
with a criteria being that the shape of the top should not include
any undercuts, for reasons explained below in relation to the
co-injection process by which the garment hanger is produced. The
garment gripping pad 30 extends across most of the width of the top
of the hanger arm, as illustrated in FIGS. 3 and 4, and is molded
to fit within a generally curved (along the direction of curvature
of each arm) rectangular shaped recess 34, having spaced side upper
edges 35, and defined within the top of the end of the hanger arm,
with the garment gripping pad projecting slightly above the
rectangular recess, as shown in FIGS. 1, 2 and 4.
[0035] The bottom of the rectangular recess 34 defines a number,
e.g. 8, of spaced, transversely extending ribs 36 projecting
upwardly from the bottom of the recess which are identical to the
number of spaced, transversely extending ribs 36 defined in the top
of the garment gripping pad, for reasons explained below with
respect the co-extrusion molding process used to produce the
garment hanger. The transversely extending ribs 36 in the bottom of
the recess also function to increase the surface area in the bottom
of the recess which contacts the second plastic material of the
co-injected garment gripping pad to increase the surface area of
the fused plastic and mechanical bond between the garment gripping
pad 30 and the main plastic structure of the garment hanger.
[0036] A unique feature of the present invention is the presence of
a plume 40 of the second plastic material of the garment gripping
pad 30, as shown best in FIGS. 2 and 3, which extends from the
inner end of the garment gripping pad into the first plastic
material forming the main body structure of the garment hanger and
which assists in anchoring and securing the garment gripping pad 30
into the main body structure of the garment hanger.
[0037] The outer end of the longitudinally extending recess 22
formed near the top center of the arm 18, 20 defines a somewhat
enlarged volume portion 42 where the flange 26 forming the top of
the longitudinally extending recess 22 joins the flange 26 forming
the bottom of the longitudinally extending recess 22 adjacent to
the inner end of the coinjected garment gripping pad. During
molding of the main plastic body member, the surfaces of the first
plastic material are partially set and hardened, and the first
plastic material in the enlarged volume portion remains relatively
unset and not completely hardened. Subsequently, during molding of
the second plastic material forming the garment gripping pad 30,
the coinjected and pressurized second plastic material breaches the
surface of the partially set and hardened first plastic material at
the enlarged volume portion and forms a plume of the second plastic
material which extends into and displaces the relatively unset and
not hardened first plastic material in the enlarged volume portion
to anchor and secure the plume of the second plastic material into
the first plastic material in the enlarged volume portion.
[0038] The entire composite coinjected hanger structure can be
molded in a co-injection mold 60 as shown diagrammatically in FIGS.
6 and 7 of the drawings. The co-injection mold 60 includes first
and second symmetrical mold members 61 which are joined along the
planes of FIGS. 6 and 7, and each of the first and second mold
members 61 forms and molds one half of a mold cavity 62 which is
shaped in the general shape of the garment hanger 10 body as
described above. The plastic mold 60 is also equipped with a
movable mold core 64 positioned between the first and second mold
members, which is translatable between first and second positions,
illustrated respectively in FIGS. 6 and 7, by a linear actuator 66,
which can be a pneumatic or hydraulic reciprocating piston and
cylinder. The movable mold core 64 is initially positioned in the
position shown in FIG. 6 when the first plastic material in a
molten state is injected therein so as to form the basic hanger
body structure, including the curved rectangular recess 34, having
the spaced side upper edges 35, and the transversely spaced,
upwardly extending ribs 36 defined on the bottom of the rectangular
recess 34. During the first step of the molding operation, the
first plastic material is injected through one or more primary
injection inlets, as is well known in the art, to form the major
portion of the garment hanger body structure, during which a
downwardly extending square or rectangularly shaped projection 68
of the movable mold core 64 covers and seals off a second injection
inlet 70, through which the second plastic material forming the
garment gripping pad is subsequently injected.
[0039] The projection 68 is positioned on one side of the
rectangular recess 34 and near the center of the length thereof,
and extends downwardly into one side upper edge 35 to form a
generally square or rectangularly shaped small access aperture 72,
FIG. 2, on one side of and near the center of the length of the
rectangular recess, the function of which is to allow the second
plastic material forming the garment gripping pad to be injected
through the second injection inlet 70 and through the aperture 72
to form the garment gripping pad after the movable mold core has
been retracted to the position of FIG. 7.
[0040] After the plastic from the primary source feeder has
completely filled the mold cavity 62, a second mold cycle is begun
in which the movable mold core 64 is withdrawn from the position of
FIG. 6 to the position of FIG. 7, which allows a second plastic
material to be injected through the second injection inlet 70 and
through the aperture 72 and into the expanded mold cavity formed by
retraction of the mold core from the position of FIG. 6 to the
position of FIG. 7. To prevent wasted plastic material which is
environmentally disadvantageous, in a preferred embodiment the
conduit extending to the injection inlet 70 is a hot runner rather
than a tunnel gate and conventional runner. The residence time of
the movable core 64 within is dependent upon the type of plastics
being used, the operating temperatures, the cycle time, and the
type of bond desired between the insert and the plastic hanger
body. After the second plastic material fills the expanded mold
cavity, the mold 60 is cooled, the side mold members 61, 61 are
separated, and the newly formed hanger is ejected from mold cavity
by means of ejector pins (not shown).
[0041] After the first molding step is completed with regard to the
injection of the first plastic material into the mold cavity 62 for
the main hanger body structure, the mold core 64 is linearly
displaced and retracted by the linear actuator 66 to the position
as shown in FIG. 7. The retracted mold core 64 preferably closes
off the injection inlet(s) for the first plastic material and
simultaneously uncovers the injection inlet 70 for the second
plastic material, and the second plastic material is then
coinjected into the mold cavity through the second injection inlet
70 and the access aperture 72. The second plastic material fills
the expanded mold cavity void formed within the mold cavity when
the mold core 64 is fully retracted to the position of FIG. 7 to
produce the garment gripping pad 30.
[0042] The movable mold core 64 molds the transversely extending
top ribs 32 of the garment gripping pad 30 when it is in the
position shown in FIG. 7, and also molds the transversely extending
bottom ribs 36 defined in the bottom of the recess 34 when it is in
the position shown in FIG. 6, which is why the pattern of the
transversely extending ribs 32 is substantially identical to the
pattern of the transversely extending ribs 36. The pattern of
transversely extending ribs is provided to enhance the ability of
the garment gripping pad to grip and secure garments thereto, but
also functions to enhance the mechanical and fused plastic
securement of the garment gripping pad 30 to the main body of the
garment hanger, by providing an irregular mechanical pattern with
increased surface area to provide an increased mechanical and fused
plastic bond between the two plastic materials.
[0043] The movable mold core 64 must be able to move freely between
its extended and retracted positions, and for that reason, the
pattern of transversely extending ribs does not include any
undercuts in the pattern.
[0044] A typical co-injection process for forming a garment hanger
as illustrated herein has an overall cycle time of 20 seconds,
during which a plastic material forming the main structure of the
garment hanger, which can be a KR01-KR03 grade K-resin, as is
commercially available from Phillips, is typically injected at a
temperature of 400 degrees F. and a pressure of 800 psi to form the
main body structure of the garment hanger. Thereafter, the movable
mold core 64 is moved and retracted to uncover the second injection
inlet 70 to allow co-injection of the second overmold material
forming the garment gripping pad. The second overmold material
might typically be DUPX-35445, Grade 1010, or Chevron 2205, and is
typically injected at a temperature of 250-300 degrees F. and a
pressure of 800 psi during a 1-2 second injection time to form the
garment gripping pad, with a typical overall cycle time to form the
coinjected garment hanger of 20 seconds.
[0045] One specific co-injection process for forming a garment
hanger with a plume as shown in FIGS. 2 and 3 had an overall cycle
time of 15.12 seconds, during which a first plastic material
forming the main structure of the garment hanger, KR03, as is
commercially available from KResin, was injected at a temperature
of 360 degrees F. and a pressure of 1320 psi to form the main body
structure of the garment hanger. Thereafter, the mold was cooled
for a period of 10 seconds, after which the movable mold core 64
was retracted to allow co-injection of the second overmold material
forming the garment gripping pad. The second overmold material
VA8.18 EVA, as is commercially available from Matrix Polymers, was
injected at a temperature of 440.degree. degrees F. and a pressure
of 727 psi to form the garment gripping pad.
[0046] Commercially available equipment has been specifically
adapted to mold the composite hanger of the present invention. An
adapted Nissei 150 ton injection molding machine was used to inject
the primary material comprising the hanger body and an adapted
injection cylinder from a Boy 10 injection molding machine was used
to inject the secondary material comprising the non-slip layer.
[0047] The primary material used in this instance is a combination
of Dow styrene grades 693 and 478. The secondary material is a D
grade material available from Shell Oils which has a trade name of
Kraton. The melt temperature of the Kraton is about
600.quadrature.F., plus or minus 50.quadrature.F. The size of the
second injection orifice is about 0.062 inches in diameter,
however, this size will vary with the design of the hanger and the
second material type.
[0048] The mold is cooled during setting periods of the
co-injection process to reduce the overall cycle time and speed
production. However, after injection of the first plastic material
forming the main structure of the garment hanger body, the first
plastic material in the interior of the enlarged volume portion 38,
formed at the junction of the top and bottom flanges 26 of the
garment-receiving slot 22 adjacent to the inner end of the
rectangular recess 34, does not cool and set completely because of
the rather large volume defined at that junction. The subsequent
pressurized co-injection of the second plastic material causes the
pressurized second plastic material to breach the surface of the
first plastic material at the location of the enlarged volume
portion 38, to form a plume 40 of the second plastic material which
displaces and bonds to the not completely set first plastic
material inside the enlarged volume portion. The injected plume 40
of the second plastic material in the large volume portion of the
first plastic material expands to a larger diameter and volume then
the breach entry passageway and serves to anchor and bond the
garment gripping pad to the main body of the garment hanger.
[0049] The bond between the non-slip garment gripping pad and the
main body of the garment hanger is a combination of a fused plastic
bond and a mechanical bond, and is supplemented by the bond between
the plume and the first plastic material in which the plume is
embedded. The factors which determine the type of bond include the
chemical compatibility of the plastics involved, the melting and
fusing temperatures of the respective plastics involved, the
temperatures at which the plastics are injected into the respective
mold cavities, the temperature at which the cavity is maintained,
and the respective dwell time between the injection of the first
plastic and the removal of the mold insert and the injection of the
second plastic. By adjusting the parameters of the process, one may
achieve a mechanical bond, a plastic molded bond, or a wholly fused
bond wherein the surface layers of the plastics have intermixed
with each other.
[0050] From the foregoing illustrations it is readily apparent that
the present invention is directed to an extremely simple composite
garment hanger construction, preferably produced in a coinjection
mold in a simple two step process which requires a minimum amount
of effort and expenditure, while being versatile in its
applications due to the specific structural aspects of the members.
No costly hand labor is required to affix the non-slip strips to
the shoulders of the hangers, which is accomplished in a single
molding operation.
[0051] The plastic materials which can be employed with the molding
operation in order to produce the inventive composite molded
plastic hanger may include, but are not limited to, plastic
materials such as polystyrene, SAN, ABS, PPO, nylon, polypropylene,
polyethylene, PET, polycarbonates, acrylics, K resin, and PVC among
others, each being provided with specific coloration in conformance
with the specific demands of the customer. When it is desired to
mold composite hangers with the non-slip inserts, polypropylene and
polyethylene primary materials may be combined with ethylene vinyl
acetate, low density polyethylene, or thermoplastic elastomers for
the non-slip layer. Alternately, if polystyrene, ABS or SAN primary
materials are desired, they may be combined with ethylene vinyl
acetate, PVC, thermoplastic elastomers or thermoplastic rubbers.
Other materials suitable for the primary body construction such as
PVC, PC, PMMA or a mixture of a polystyrene with one of the
foregoing primary materials may be used with EVA, PVC,
thermoplastic elastomers or thermoplastic rubbers and the non-slip
insert material.
[0052] In one preferred embodiment, styrene or polypropylene is
used as the primary material with a softer material (such as a
thermoplastic rubber including, but not limited to, Kraton) used
for the insert. In another embodiment a harder material can used as
the insert including, but not limited to, polyethylene with a
propylene membrane.
[0053] More particularly, when a chemical bond is desired, it is
preferable to use styrene main as the primary material with styrene
or polypropylene main as the primary material with EVA/PP mix. When
a chemical and mechanical bond is desired, it is preferable to use
styrene main as the primary material with styrene rubber. When a
mechanical bond is desired, it is preferable to use polypropylene
main as the primary material with polyethylene.
[0054] While there have been shown and described what are
considered to be the preferred embodiments of the invention, it
will, of course, be understood that various modifications and
changes in form or detail can readily be made without departing
from the spirit of the invention. It is therefore intended that the
invention not be limited to the exact form and detail herein shown
and described nor to anything less than the whole of the invention
herein disclosed as hereinafter claimed.
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