Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a method and apparatus for
the preparation of multilayer laminates from -thermoplastic
materials.
In accordance with themethod of this invention improv~
ed laminates are readily prepared by pro~iding a pluralit~
of adjacent streams of thermoplastic material in conticJuous
relationship to each other, altering the cross~sectional
configuration of the plurality of streams by reducing the
dimension of the stream perpendicular to interfaces between
the individual streams and increasing the dimension in a
direction transverse to the direction of flow and generally
parallel to the interfaces of the streams.
The method of the invention is advantageously carried
out with the apparatus of this invention which comprises in
cooperative combination a housing defining a paSSaCJeway, the
passageway having an en-trance and an exit, the entrance having
a first axis and a second axis, the exit having a first axis
and a second axis , the first axes of the entrance and the exit
~ being coplanar and the second axes of the entrance and the
exit being coplanar, the first and second axes of the entrance
and the exi-t being disposea generally normal to each other,
the first axis of the entrance being the major axis and the
second axis th.e minor axis, the fi.rst axis of the exit being
the minor a.xis and the second axis of the exit being the major
axis, the passageway being so constructed and arranged so as
t~ permit streamlineflowof a fluid therein and the length of
the first axis of the major entrance being substantially great-
er than that of the first axis of the exit.
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As will be described in detail hereinafter, the
invention provides a method of preparing a sheet of thermo-
plastic resinous materials by extruding in an extrusion appa-
ratus wherein the materials are arranged as a pluralit~ of
laminae having major surfaces generally parallel to the major
surfaces of the resultant sheet. The steps of the method com-
prise; (a) providing by extruding in an extrusion apparatus a
plurality of closel~ adjacent flowing streams of diverse
: thermoplastic materials in a heat plastified condition in con-
tiguous relationship to each other, each stream having gener-
ally planar surfaces which are generally parallel, (b) altering
the cross-sectional configuration of th~ plurality of flowing
streams by reducing the dimension of the stream in a direction
generally perpendicular to interfaces between the individual
streams, and (c) inc~easing the dimension of the stream in a
direction transverse to the direction of flow and generally
parallel to the interface of the streams to form a sheet-like
configuration having a plurality of layers wherein the layer
interfaces are in generally parallel relationship to each other
and to major surfaces of the sheet-like configuration.
In a different aspect, the invention described herein
provides a method for preparing a sheet of thermoplastic
resinous materials wherein the materials are arranged as a
plurality of laminae, the sheet and the laminae having major
surfaces which are generally parallel to the major surface of
the resultant sheet. The steps of the method comprise:
extruding at least a first heat plastified synthetic resinous
material and a second heat plastified synthetic resinous
material to provide first and second heat plastified resinous
streams, each stream being of diverse material; subdividing
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the first and second streams into first and second substreams,
interdigitating the first and second substrearns to form a
stream having an elongate cross-sectional configura~ion, the
configura~ion having a first side, a second side, a first edge
and a second edge, the substreams having generally planar
interfaces and the substreams extending from the first side to
the second side of the cross-sectional configuration; deforming
the stream by forcing the edge portions into generally adjacent
relationship and the side portions into remote relationship,
thereby forming a stream having a generally elongat~
cross-sectional configuration having sides corresponding to the
edges of the interdigitated substreams and edges corrasponding
to the sides of the interdigitated substreams, subsequently
¦ extruding, and; cooling the deformed stream to form a laminate
sheet of synthetic resinous thermoplastic materials having
major surfaces generally parallel to the major surfaces of the
extruded stream.
Thus, in accordance with a broad aspect of the
invention, there is provided a method of preparing a sheet of
thermoplastic resinous materials wherein the materials are
arranged as a plurality of laminae having major surfaces
generally parallel to the major surfaces oE the resultant
sheet, characterized by (a) providing a plurality of closely
adjacent streams of diverse thermoplastic materials in a heat
plastified condition in contiguous relationship to each other,
(b) altering the cross-sectional configuration of the plurality
of streams by reducing the dimension of the streams in a
direction generally perpendicu~ar to interfaces between the
individual streams and (c) increasing the dimension of the
streams in a direction transverse to the direction of flow and
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gene~ally parallel to the interface of the streams to form a
sheet-like configuration.
In accordance with another broad aspect of the inven-
tion there is provided apparatus for preparing laminates of
thermoplastic resinous materials characterized hy a housing
defining at least one cavity therein and adapted to receive at
least a first and second heat plastified thermoplastic stream,
means to distri.bute the streams into a plurality of smaller
streams, the smaller streams being in generally alternate
arrangement with smaller streams from the first stream being in
alternating arrangement with the smaller streams from the
. second stream, the housing defining a passageway, the passage-
way having an entrance and an exit, the entrance having a first
axis and a second axis, the exit having a first axis and a
second axis, the first axes of the entrance and the exit being
coplanar and the second axes of the entrance and the exit being
I coplanar, the first and second axes of the entrance and the
exit being disposed generally normal to each other, the first
axis of the entrance being the major axis and the second axis
- 20 the minor axis~ the first axis of the exit being the minor axis
and the second axis of the exit being the major axis, the
passageway being constructed and arranged to permit streamline
flow of a fluid therein and the length of the first axis of the
major entrance being substantially greater than that of the
first axis of the exit.
In accordance with another broad aspect of the inven-
tion there is provided an extrusion apparatus for extruding
laminated plastic products; said extrusion apparatus including
an extrusion die defining a flow path for fluid products and
1 30 having a thin elongated discharge orifice comprising, a first
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conduit passageway having one end adapted to be connected to a
first extruder, a second conduit passageway having one end
adapted to be connected to a second extruder; said first and
second conduit passageways communicating with said flow path;
whereby materials flowing from said first and second conduit
passageways are laminarly joined under pressure before extru-
sion through said discharge orifice; said flow path having a
divergent portion toward said discharge orifice, whereby said
laminarly joined extruded materials are lateral].y extended
prior to discharge from said discharge orifice.
The invention will become more apparent from the
following specification when taken in connection with the
drawing wherein:
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Figure 1 is a schematic representation of a simplified
appara~us in accordance with the invention showing an enlarged
section of the product thereo~;
Figure 2 is a sectional view through a distribution
manifold of ~he appara~us of Figure l;
Figure 3 shows a view of a distribution block employed
in the manifold;
Figure 4 is a schematic isome~ric representa~ion of a
transition piece as utilized in the appara~us of Figure l;
Figure 5 is an alternate configuration of a transition
piece;
Figure 6 is an alternate embodiment of a manifold and
Figure 7 is a view of a portion of a feed port block
for use in the manifold of Figure 6.
In Figure 1 there is illustrated an apparatus in
accordance with the inven~ion generally designated by ~he ref-
erence numeral 10. The apparatus comprises ~n cooperative
combination a first extruder 11, a second extruder 12, a dis-
tribution manifold 13, in full communication with the extruder
11 by means of the eonduit 15 and in communication with the
extruder 12 by means of the conduit 16. A transition piece 17
having an inlet or first opening ~8 and a second or outlet open-
ing 19 is in communication with the discharge of the manifold
13. A laminated film 20 issues from the discharge opening 19
Adjacent ~he opening 19 are cooling means 22 which reduce the
temperature of the laminate film or sheet 20 to a temperature
below the thermoplastic temperature thereof. The film or sheet
20 is wound onto a takeup means or roll 23. An enlarged portion
of 20a of the film 20 is shown d~pic~ing a plurality of laminae
25 and 26 of material from the extruders 11 and 12 9 respectively.
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In Figure 2 there is illustraked a sectlonal view o~
the mani~old 13. The manifold 13 comprises a ~irst maJor
passageway 30 in communica~ion with the conduit 15, a second
major passageway 31 in communlcation with the condu.it 16 ~not
shown), an extrusion slot or orifice 33, and a diskribution
block 35. The distribution block 35 defines a plurality o~
passageways 36 and a plurality o~ passagewa~s 37, The passage-
ways 36 provide communication between the ~irst major passage-
way 30 and the exkr~sion ori~ice 33. The passageways 37 provide
commun~cation between th~ second ma~or passageway 31 and the
exkrusion ori~ice 33. The passageways 36 and 37 are so ¢ons-
: tructed and arranged that the~ alternate in the distribution
block and provide interdigi~ated ætreams o~ the material ~lowing
from the ~irst and second ma~or passageway~ 31 to ~he extrusion
ori~ices 33.
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~ In Fig~re 3 a front par~ial view of the distribution
i block 35 is ~hown illus~rating the relationship between the
~ passagewa~s or channels 36 and 37 illus~ra~ing th~ interdl~ltated
;` discharge o~ the thermoplastic materials,
In Figure 4 there is lllustrated an isomekric repre-
sentation of a transition piece 17 having an inlet opening 18
and an outlet opening 19. A passageway 40 provides full communi-
cation between the inlet and outlet opening and permits stream-
line ~low o~ a liquid ~rom the opening 18 to the opening 19
without rotation of the ~low lamina, The ~nlet openlng 18 has
a ~irst or maJor axis a and a second or minor axis b. The out-
~ let opening 19 has a ~irst axis a' and a second axis b'. The
,~ ~ axes a and a' are generally coplanar and the axes b and b' are
~,` generally coplanar. The transition piece o~ Flgure 4 is an
exponential transition piece o~ constank cross-sectional area
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wherein its length is arbitrarlly selected and the central
portlon has a square cross-section having a length 1~ b and h
are the deslred width and hei~ht of one of the openings. The
equation of the outline of ~he trans~tion section such as is
seen in Figure 1 if a z axis is assumed to run vertically is
z~ h (h) / . The equation .~or a line drawn cen~rally khrou~h
the conduit and correspondlng to the outline in a plane 90 ~o
the observed plane of Figure 1 is~ y= ~h (~) . The exponen
tlal transltion section is particularly advantageou~ and bene-
ficlal if uni~orm flow rate within the transitlon piece ls to
be maintained For many purpo~es a kransition piece such as is
illustrated in Flgure 5 is adequate. A transition piece of
Figure 5 generally designated b~ the re~erence numeral 45 com-
prises a hou~ing 46 de~ining an inlet passage 47J an outlet
passage 48 and an internal interconnectlng channel 49 so cons-
tru¢ted and arranged ~o as to permit sub~tantially streamlined
flow of material entering the passageway 47 and being discharged
~rom the opening 48.
In Flgure 6 there is illustrated an alternate con~i~u
ration of a manif'old generally designated by ~he reference numer-
al 55 The manifold 55 comprises a housing or body 56 hav~n~
deflned thereLn an exkrusion orifice 57, ~irst, second and third
ma~or passageways 58~ 59 and 60 respectively, which are in
communication with thermoplastic material supply conduits 61,
62, and 63J respectively. A distribution block 65 is dlsposed
within ~he body 56 and defines a plurality of passageways 66
providing communicatlon between the first ma~or passageway 58
and the extrusion aperature 57, a plurality o~ passagewa~s 67
providing commu~ication between the ma~or pas~ag~way 59 and
the extrusion opening 57, a plurality o~ passageways 68 prov-ld-
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ing communication between the third maJor passageway 60 and the
extrusion orifice 67. The passagewa~s 66, 67 and 68 are
alternately arranged in the distri'~ution block 65.
In Figure 7 a front view of a portion o~ the distri-
bution block 65 is shown depicting the relationshlp between the
passageways 66, 67 and 68, Each o~ the passageways terminate
in an opening ~ubstantially commensurate with the width of the
extrusion passage 57. The embod~ment of Figure 6 is particularly
advanta~eous when it is desired ~o prepare a laminate having
three ¢omponents and a plurality of layers.
In operation o~ the apparatus ~n-accordance wlth the
invention thermoplast~c re~nous materlal in a hea~ plastified
condition is extru~ed from the extruders ll and 12, passed into
the mani~old 13 to the pas~ageways 30 and 31 respecti~ely. The
heat plastified material from the passageway 30 flows to the
extrusion orifice 33 by way of passageway 36. ~he material
~rom the extruder 12 ~lows into a pa~sageway 31 a~d is discharged
lnto the passageway 33 in interdigitating relationship with the
materlal ~rom the extruder ll. Thus a striped sheet or stream
is formed wherein the diverse mater-lals extend from one major
~ur~ace to the opposlte ma~or surface. On passing into the
tran~ition section the extruded sheet in ef~ect is squeezed or
reduced ~in width) and expanded in a direction corresponding
to its thickness u~til on emerging ~rom the outlet the portion
o~ the sheet originally representing the edge is now a ma~or
surface or the width and that which had heretofore been the
thickness of the sheet is now the width. As the transition
~` piece permits linear or streamline flow, the various component~
~ are repositioned in such a manner that a num~er of thi~ layers
' 3 o~ material in the form o~ a compo~ite sheet are obtained with-
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out the necessity o~ employing a plurality o~ slot dies. The
relative thickness of the various layers is readily controlled
by varying the quantity of ma~erial provided to the manifold
by the extruders, Thus it is possible to have the various
materials present in the deslred proportion. Due to the realtive-
ly large size Or the various ~eed por~s def~ned in the distribu-
- tion block3 control of the thickness of the varlous layers is
readily accomplished without the necessity o~ maintaining the
extremely high dimensional tolerances that are necessary when
conventional ~ilm and sheetlng dies are utilized to prepare
laminates, The embodiment o~ Figures 6 and 7 are readily utll-
ized by employing the required number o~ streams of thermo-
plastic resinous material to provide the desired laminate.
Employing an apparatus generally ~imilar to the appara-
tus 10 of Figure 1, equal quantities o~ polyskyrene and poly-
methyl methacrylate are extruded at a rate o~ about 15 pounds
(6,8 kgs) per hour into a sheet about 4 inches (10 cm) in wldth
and about 1/8 inch (3.2 mm~ ln thickne~s. The sheet consi~ted
of 125 layers alternately o~ polystyrene and polym~thyl methacry~
~ late, On microscopic examination) the layers were determined
to be substantlall~ parallel to the sur~aces o~ the sheet and
o~ uniform thickness. The resultant sheet was more ~lexible
and had higher impact resistance than a like sheet of polystyrene
or polymethyl methacrylate.
~5 The foregoing example is repeated employing polystyrene
in combination with a gr~ntlnted nylo~. Slmilar results were
obtained. Beneficial laminates are also prepared ln accordance
with the inventlon employing, for example, polypropylene~
polyvinylchloride, polypropylene-polystyrene, ethyl cellulose-
polystyrene, polyethylene-polystyrene, polypropylene-polyethylene
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and polyvinylchloride copolymer of vinyl chloride and vlnylidenechloride. As is evident the relative thicknesses o~ the like
material are proportional to the amount o~ material issuing
~rom the appropriate passageway or ~eed port in the die. Thus,
by varying the dimensions o~ the feed ports, heavier or thicker
layers may be employed at desired locations within the ~ilm.
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